Slender Bush-clover (Lespedeza virginica) in Ontario - Ontario Recovery Strategy Series

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Slender Bush-clover (Lespedeza virginica) in Ontario - Ontario Recovery Strategy Series
Photo: Allen Woodliffe

                                                         Slender Bush-clover
                                                         (Lespedeza virginica) in Ontario

                                                         Ontario Recovery
                                                         Strategy Series
                                                         Recovery strategy prepared under the Endangered Species Act, 2007

                                                         2013

                         Ministry of Natural Resources
Slender Bush-clover (Lespedeza virginica) in Ontario - Ontario Recovery Strategy Series
About the Ontario Recovery Strategy Series
This series presents the collection of recovery strategies that are prepared or adopted
as advice to the Province of Ontario on the recommended approach to recover
species at risk. The Province ensures the preparation of recovery strategies to meet
its commitments to recover species at risk under the Endangered Species Act
(ESA) and the Accord for the Protection of Species at Risk in Canada.

What is recovery?                                               What’s next?
Recovery of species at risk is the process by which the         Nine months after the completion of a recovery strategy
decline of an endangered, threatened, or extirpated             a government response statement will be published
species is arrested or reversed, and threats are                which summarizes the actions that the Government of
removed or reduced to improve the likelihood of a               Ontario intends to take in response to the strategy.
species’ persistence in the wild.                               The implementation of recovery strategies depends on
                                                                the continued cooperation and actions of government
                                                                agencies, individuals, communities, land users, and
What is a recovery strategy?                                    conservationists.
Under the ESA a recovery strategy provides the best
available scientific knowledge on what is required to
                                                                For more information
achieve recovery of a species. A recovery strategy
outlines the habitat needs and the threats to the               To learn more about species at risk recovery in Ontario,
survival and recovery of the species. It also makes             please visit the Ministry of Natural Resources Species at
recommendations on the objectives for protection and            Risk webpage at: www.ontario.ca/speciesatrisk
recovery, the approaches to achieve those objectives,
and the area that should be considered in the
development of a habitat regulation. Sections 11 to 15
of the ESA outline the required content and timelines
for developing recovery strategies published in this
series.
Recovery strategies are required to be prepared for
endangered and threatened species within one or two
years respectively of the species being added to the
Species at Risk in Ontario list. There is a transition period
of five years (until June 30, 2013) to develop recovery
strategies for those species listed as endangered or
threatened in the schedules of the ESA. Recovery
strategies are required to be prepared for extirpated
species only if reintroduction is considered feasible.
Slender Bush-clover (Lespedeza virginica) in Ontario - Ontario Recovery Strategy Series
Recovery Strategy for the Slender Bush-clover in Ontario

RECOMMENDED CITATION
Jones, J. 2013. Recovery Strategy for the Slender Bush-clover (Lespedeza virginica) in
Ontario. Ontario Recovery Strategy Series. Prepared for the Ontario Ministry of Natural
Resources, Peterborough, Ontario. vi + 26 pp.

Cover illustration: Slender Bush-clover at Ojibway Prairie by Karen Cedar.
This photo may not be reproduced separately from this recovery strategy without
permission of the photographer.

© Queen’s Printer for Ontario, 2013
ISBN 978-4606-3063-1(PDF)

Content (excluding the cover illustration) may be used without permission, with
appropriate credit to the source.

Cette publication hautement spécialisée Recovery strategies prepared under the
Endangered Species Act, 2007, n’est disponible qu’en Anglais en vertu du Règlement
411/97 qui en exempte l’application de la Loi sur les services en français. Pour obtenir
de l’aide en français, veuillez communiquer avec Pamela Wesley au ministère des
Richesses naturelles au 705-755-5217.

                                               i
Recovery Strategy for the Slender Bush-clover in Ontario

AUTHORS
Judith Jones, Winter Spider Eco-Consulting, Sheguiandah, Ontario

ACKNOWLEDGMENTS
The Committee on the Status of Endangered Wildlife in Canada is thanked for providing
information from the 6-month interim 2012 status report. Thanks to Sam Brinker and
Mike Oldham for providing additional information on habitat; to P. Allen Woodliffe for the
photo in Figure 1 and for information from past field work; to Paul Pratt for providing
data from the Ojibway Nature Centre; and to Karen Cedar of the Ojibway Nature Centre
for providing the cover photo.

                                               ii
Recovery Strategy for the Slender Bush-clover in Ontario

DECLARATION
The recovery strategy for the Slender Bush-clover was developed in accordance with
the requirements of the Endangered Species Act, 2007 (ESA). This recovery strategy
has been prepared as advice to the Government of Ontario, other responsible
jurisdictions and the many different constituencies that may be involved in recovering
the species.

The recovery strategy does not necessarily represent the views of all of the individuals
who provided advice or contributed to its preparation, or the official positions of the
organizations with which the individuals are associated.

The goals, objectives and recovery approaches identified in the strategy are based on
the best available knowledge and are subject to revision as new information becomes
available. Implementation of this strategy is subject to appropriations, priorities and
budgetary constraints of the participating jurisdictions and organizations.

Success in the recovery of this species depends on the commitment and cooperation of
many different constituencies that will be involved in implementing the directions set out
in this strategy.

RESPONSIBLE JURISDICTIONS
Ontario Ministry of Natural Resources
Environment Canada – Canadian Wildlife Service, Ontario

                                               iii
Recovery Strategy for the Slender Bush-clover in Ontario

EXECUTIVE SUMMARY
Slender Bush-clover (Lespedeza virginica) is listed as endangered under Ontario’s
Endangered Species Act, 2007 and on Schedule 1 of the federal Species at Risk Act. It
is a perennial herb in the Pea Family with pink flowers and many narrow leaves
crowded on upright stems. The seeds can remain viable for decades and can pass
unharmed through the gut of an animal.

In Canada, Slender Bush-clover is present only in Ojibway Park and possibly at
Tallgrass Heritage Park and Black Oak Heritage Park, all part of the Ojibway Prairie
Complex in the City of Windsor, Ontario. Collectively, these three sites comprise a
single population. The species has not been seen at Tallgrass Park since 1997 or at
Black Oak Park since 1993. It is unknown whether the seed bank is still viable at these
locations. Plants growing above ground were seen at Ojibway Park in 2011.

In Ontario, Slender Bush-clover is extremely limited by a lack of suitable habitat. In this
province, the species is restricted to dry-mesic tallgrass prairie relicts with patches of
exposed sandy soil. It requires full sun and open ground and does not tolerate dense
shade or competition from surrounding vegetation. Some type of disturbance is needed
to create open soil. Historically, this was probably fire or periodic drought. Existing
habitat is highly fragmented into small patches that are isolated from one another by
distances of hundreds of metres or more. Disturbance factors are also needed to
disrupt the seed coat to improve germination.

Slender Bush-clover may be limited by some aspects of its reproductive biology. First,
the relatively short growing season in Ontario might cause lower seed productivity than
is found in populations in the southern part of the species' range. Second, factors
responsible for breaking seed dormancy (such as fire, abrasion by sand, ingestion by
herbivores) might be lacking at extant sites. Finally, the small, isolated Canadian
population of Slender Bush-clover is at risk of being destroyed by a single stochastic
event, such as a flood or wind storm.

The most serious threat to Slender Bush-clover is alteration of the natural disturbance
regime (e.g., suppression of natural wildfire), which allows natural succession to
proceed, resulting in habitat degradation or loss. Invasive species are another threat in
need of urgent attention. All-terrain vehicle and dirt bike use are no longer threats.

The recovery goal is to maintain the abundance and distribution of growing plants of
Slender Bush-clover at Ojibway Park at current or greater levels by reducing threats,
and if the species is extant in the seed bank at the other two subpopulations, to
increase the number of growing plants present there to pre-1995 levels. The protection
and recovery objectives are to:
    1. maintain or improve habitat suitability at the three existing sites;
    2. reduce presence of invasive species at the three existing sites;
    3. fill knowledge gaps; and
    4. increase population size and extent if deemed feasible.

                                                iv
Recovery Strategy for the Slender Bush-clover in Ontario

It is recommended that a habitat regulation cover all three Windsor sites and that at
Ojibway Park the entire opening where the species occurs plus a protective zone of 50
m around the outside of the opening be prescribed. A definition of "opening" is given in
the body of the text. At Tallgrass and Black Oak Heritage Parks it is recommended that
a 50 m zone around the former area of live plants be prescribed as habitat to protect the
seed bank and allow disturbance to occur even though live plants have not been seen
in recent years. It is recommended that the Tallgrass and Black Oak sites be
prescribed for 50 years unless live, growing plants of Slender Bush-clover re-emerge in
which case habitat would remain prescribed beyond this time. It is recommended that
restoration populations be regulated if they are planted within the three parks where the
species is endangered and in natural vegetation but not in garden beds.

                                               v
Recovery Strategy for the Slender Bush-clover in Ontario

TABLE OF CONTENTS
RECOMMENDED CITATION ........................................................................................... i
AUTHORS ....................................................................................................................... ii
ACKNOWLEDGMENTS .................................................................................................. ii
DECLARATION ............................................................................................................... iii
RESPONSIBLE JURISDICTIONS .................................................................................. iii
EXECUTIVE SUMMARY.................................................................................................iv
1.0   BACKGROUND INFORMATION .......................................................................... 1
  1.1   Species Assessment and Classification ............................................................ 1
  1.2   Species Description and Biology....................................................................... 1
  1.3   Distribution, Abundance and Population Trends ............................................... 4
  1.4   Habitat Needs ................................................................................................... 7
  1.5   Limiting Factors ................................................................................................. 8
  1.6   Threats to Survival and Recovery ..................................................................... 9
  1.7   Knowledge Gaps............................................................................................. 10
  1.8   Recovery Actions Completed or Underway..................................................... 11
2.0   RECOVERY ....................................................................................................... 13
  2.1   Recovery Goal ................................................................................................ 13
  2.2   Protection and Recovery Objectives ............................................................... 13
  2.3   Approaches to Recovery ................................................................................. 14
  2.4   Area for Consideration in Developing a Habitat Regulation ............................ 17
GLOSSARY .................................................................................................................. 21
REFERENCES .............................................................................................................. 23

LIST OF FIGURES
Figure 1. Flowering clusters of Slender Bush-clover ...................................................... 2
Figure 2. Historical and current distribution of Slender Bush-clover in Ontario. ............. 5

LIST OF TABLES
Table 1. Conservation ranking for Slender Bush-clover. ................................................ 5
Table 2. Abundance of Slender Bush-clover at the Ojibway Park site............................ 6
Table 3. Protection and recovery objectives................................................................. 13
Table 4. Approaches to recovery of the Slender Bush-clover in Ontario. ..................... 14

                                                                vi
Recovery Strategy
                                S        for th
                                              he Slender Bu
                                                          ush-clover in O
                                                                        Ontario

 1.0    BACKGR
             ROUND IN
                    NFORMAT
                          TION

1.1    Species
       S       Assessme
               A      ent and Classifica
                              C        ation

COMMO
    ON NAME: Slender Bush-clover
                     B         r

SCIENT
     TIFIC NAME
              E: Lespede
                       eza virginica

SARO List
      L Classificcation: End
                           dangered (wwithin Tallgrrass Prairie
                                                              e Heritage P
                                                                         Park, Ojibw
                                                                                   way
Park and
       d Black Oak Heritage Park in the
                                      e City of Winndsor)

SARO List
     L History: Endangere
                        ed (2008), Endangere
                                           ed – Regula
                                                     ated (2004)

COSEW
    WIC Assessment History: Endang
                                 gered (2000
                                           0, 1986)

SARA Schedule
     S        1: Endangere
                         ed

CONSERVATION STATUS RANKINGS:
                    R       :
        GRANNK: G5            NRANK: N
                                     N1                                       SRANK: S1

The glosssary provid
                   des definitio
                               ons for the abbreviatio
                                                     ons above a
                                                               and for othe
                                                                          er technical
terms in this recove
                   ery strategy
                              y.

1.2    Species
       S       Descriptio
               D        on and Biiology
Species Description
Slender Bush-clove    er (Lespede
                                eza virginicca (L.) Britto
                                                         on) is a pere  ennial herb
                                                                                  b in the Legume
or Pea Family
        F        (Fabbaceae). The upright hairy
                                             h     stemss, 30 to 100  0 cm tall, arrise from a
woody rhizome and     d sometimees branch near
                                            n    the top p. Numerou    us narrow, tthree-parte ed
leaves thhat are stroongly ascennding (pointting up) gro ow from the  e main stem m on short (1
cm) stalks, giving th he stem a crowded,
                                 c         sppike-like proofile. In latte summer, small, purp   ple
to pink pea-like
        p         flow
                     wers, 4 to 7 mm acros  ss, are prodduced in sho   ort clusters in the axilss of
the leaves (Figure 1). Two typ   pes of floweers are prod duced: thosse that ope  en and have  e
showy petals,
        p        and those that are
                                 a smallerr, remain clo   osed, and a  are self-ferttile. Follow
                                                                                               wing
pollinatio
         on, a flat, oval-shaped
                     o          d pod 4-7 mm
                                           m in diame    eter contain ning one se eed is produ uced
from botth types of flowers
                      f       (Cle
                                 ewell 1966, Gleason a   and Cronqu   uist 1991).

Slender Bush-clove  er may be distinguishe
                               d           ed from oth er species of Bush-clo  over that ha
                                                                                          ave
upright stems
        s       and purple-colooured petalss by the folllowing charracteristics::
    narrow, strap-shaped le    eaves (not oval shape ed);
    le eaves some  ewhat hairyy (but not de
                                           ensely velvvety);
    numerous, non-opening
                    n           g flowers present (mo ore than justt a few pressent), and
    flowers with open corolllas on shorrt stalks or sitting direcctly on the sstem (not oon
       sttalks nearly
                    y the length
                               h of leaves).

                                                  1
Recovery Strategy for the Slender Bush-clover in Ontario

Figure 1. Flowering clusters of Slender Bush-clover showing both the showy and the
non-opening flowers. (Photo: P.A. Woodliffe. This photo may not be reproduced
separately from this document without permission of the photographer.)

Species Biology
Slender Bush-clover is a perennial that comes up each year from underground woody
rhizomes. Clewell (1964) counted the annual growth rings on rhizomes of Hairy Bush-
clover (L. hirta) and Wand-like Bush-clover (L. intermedia) in southern Indiana and
found plants lived up to 13 to 17 years, which may give an indication of the potential life
span of the growing plants of Slender Bush-clover as well. Like other plants in the
Legume family, Slender Bush-clover has nitrogen-fixing bacteria in nodules on the
rhizome (Yao et al. 2002). This symbiotic association enables Slender Bush-clover to
grow in nitrogen-poor soils.

In Ontario, Slender Bush-clover flowers in August and September and produces both
open (chastogamous) flowers and closed (cleistogamous) flowers that self-pollinate.
Both kinds of flowers produce viable seed. The ratio of the different flower types
produced may change in response to different environmental conditions or stresses
(Clewell 1964, Schutzenhofer 2007). More closed flowers are produced when plants
are stressed. These flowers have smaller petals and no nectar and require less energy
to produce. Thus, they may be a smaller energy investment that guarantees
reproduction when conditions are less than optimal.

The open flowers of Slender Bush-clover are likely pollinated by a variety of insect

                                                2
Recovery Strategy for the Slender Bush-clover in Ontario

species, with bees, butterflies, and moths probably being the main pollinators (Pratt
1986). Clewell (1966) observed honeybees and several types of bumblebees on bush-
clovers in Indiana. Simpson (1999) removed competing species in plots to see if
Slender Bush-clover was limited by pollination. In the first year, she found an increase
in insect visits but no increase in seed-set and concluded that pollination was already
above a threshold level for seed set. In the second year, she found a stronger
correlation between insect visits and amount of seed set because overall visitation was
low. This suggests that Slender Bush-clover can be limited by pollination depending on
conditions for pollinators in any given year.

Both the showy and non-opening flowers of Slender Bush-clover produce viable seeds.
However, seeds of non-opening flowers have slightly lower viability (Schutzenhofer
2007). Schutzenhofer (2007) examined the effects of herbivory on the production of
both types of flowers and found that herbivory resulted in an increase in the ratio of non-
opening flowers over showy flowers. Since seeds of non-opening flowers have lower
viability, this change in ratio may have consequences for overall reproductive success.
No significant difference was found in germination rates between seeds produced from
showy flowers and those of non-opening flowers, but rates for both types of seeds were
low. No analysis has been done that would take into consideration any benefit provided
if herbivory results in increased seed dispersal distances or improved seed germination
rates. It can be speculated that the amount of herbivory within a patch, as well as the
parts of the plant eaten, may make a difference.

The seeds of Slender Bush-clover have a hard, impervious seed coat that permits them
to pass unharmed through animal digestive systems and to remain viable in the soil for
long periods of time. The seed coat must be scarified or disrupted in some way before
germination can occur. Passage through an animal gut may improve germination for
seeds of Slender Bush-clover. Blocksome (2006) found improved germination rates for
seeds of Chinese Bush-clover (L. juncea var. sericea) after passage through the gut of
quail. Clewell (1966) reported a 100% germination rate for seeds of Slender Bush-
clover manually scarified with a scalpel versus 0% for seed that was not scarified. As
well, Clewell (1966) successfully germinated seeds taken from a 54-year-old herbarium
specimen, showing that under some conditions seeds may remain viable for many
decades. The actual time that Slender Bush-clover seeds can remain viable outdoors in
soil is unknown. If seeds do not pass through an animal gut, some other natural
process may be needed to disrupt the seed coat. It can be speculated that fire or
possibly abrasion by sand may provide this function.

At the Ontario location for Slender Bush-clover, in the Ojibway Prairie Complex in the
City of Windsor, a number of animals and birds are present that may eat the seeds of
Slender Bush-clover, including White-tailed Deer (Odocoileus virginianus), Northern
Bobwhite (Colinus virginianus), Wild Turkey (Meleagris gallopavo) and Mourning Dove
(Zenaida macroura), as well as many small mammals such as mice and rats (Pratt
1986, Blocksome 2006, Ojibway Nature Centre 2012). The seed of Slender Bush-
clover may be dispersed by animals if eaten and expelled in feces at another location.
It is not known whether animals are the main dispersal vector of Slender Bush-clover,

                                                3
Recovery Strategy
                                S        for th
                                              he Slender Bu
                                                          ush-clover in O
                                                                        Ontario

but some other spe ecies of bus
                              sh-clovers are
                                           a dispersed primarilyy by animals (Blockso      ome
2006). The
        T likeliho ood of the seed
                              s     of Slen
                                          nder Bush-cclover passsing through    h the gut ra
                                                                                           ather
than being broken down durin  ng digestionn is not knowwn, but it iss possible that an animmal
may be both a seed  d predator and an occ casional disspersal vecttor. There may be a
trade-offf between having
                   h       a se
                              eed that is an
                                          a attractivee food sourrce to anima   al vectors a
                                                                                           and
losing so
        ome seed tot animal diigestion. If not eaten, the fruits oof Slender B Bush-cloverr
stay on the plant th
                   hrough the fall
                               f and win  nter, eventu
                                                     ually falling and openin  ng to releasse
the seedd (Clewell 1966).
                   1

Several ecological processes must occur for successsful germination. The           ese include e
suitable disturbanc ce to exposee mineral soils (ground   d fires, scra
                                                                      aping, etc.) and action  ns
that scarify or disru
                    upt the seedd coat (fire, passage th  hrough an a animal gut, being rubb   bed
by sand, etc.) as well
                   w as suitable moisturre condition     ns. In contrrolled garde en trials in
Indiana, Clewell (19 966) found plants of Hairy
                                            H      and WWand-like Bush-clover were able tto
reach maturity
       m         and bear seed in the first year after g  germination n, but foundd seedlings in
natural populations
        p           s either didn
                                n't flower in the first ye
                                                         ear or floweered but pro oduced few
seeds. It is unknow wn whetherr flowering in i the first yyear is posssible for Sle
                                                                                  ender Bush  h-
        n Ontario. The
clover in            T species  s also is abble to sprea ad from sho ort, undergro ound stolon ns or
from fraggments of the
                     t woody rhizome
                                r         (Clewell 1964  4). The pre esence of underground     d
woody rhizomes, a hard seed coat, and the    t ability to o spread froom fragments are
adaptations that alllow Slender Bush-clov   ver to survivve the fire oor other dissturbance th hat is
requiredd to create and
                     a maintain suitable habitat.

Slender Bush-clove  er appears to be a pooor competito or and growws best when not crow  wded
by otherr vegetation
                   n. In a stud
                              dy of severaal species oof bush-clovver growing g on both
eroded and
         a non-ero  oded soils, Slender Buush-clover g grew taller and had increased yie  eld
(dried biiomass), inc
                    creased winnter surviva
                                          al and grea ter survivall of seedling
                                                                              gs in plots tthat
were we eeded to redduce comp petition rega
                                          ardless of ssoil type (Ha
                                                                  arris and Drrew 1943).

1.3    Distributio
       D         on, Abun
                        ndance an
                                nd Popula
                                        ation Tre
                                                ends
In Canada, Slender Bush-clov    ver has beeen documen  nted only in
                                                                  n southwesttern Ontario  o
(Figure 2).
         2 In the United
                    U       State
                                es, Slenderr Bush-clovver is found in 26 state es, and in
northernn Mexico it is
                     i present in the state of Nuevo L Leon. Table e 1 shows tthe state orr
provinciaal conservaation rankin
                               ngs (S ranks s) for Slend
                                                       der Bush-clover (NaturreServe 20   012).
The spe ecies is not consideredd rare within
                                           n the core oof its Midwe
                                                                  estern range but is ran nked
rare in northern
        n         are
                    eas. In adddition, Slend
                                           der Bush-cllover is legaally listed a
                                                                               as threateneed in
New Hampshire an    nd Wisconsin. Globally, the speccies is considered secu     ure and ran
                                                                                          nked
G5 (NatureServe 2012).
                   2

                                                  4
Recovery Strategy for the Slender Bush-clover in Ontario

Figure 2. Historical and current distribution of Slender Bush-clover in Ontario.
 Solid circle: extant population consisting of three subpopulations in the Ojibway Prairie
Complex in the City of Windsor. Open circle: historical record from the Leamington area
not seen since 1892.

Table 1. Conservation ranking for Slender Bush-clover by state or province
(NatureServe 2012).

State or Provincial Conservation Rank   States with this rank
Critically imperilled (S1)              New Hampshire, Ontario
Imperilled (S2)                         Wisconsin
Possibly vulnerable (S3?)               New York
Apparently secure (S4)                  Iowa, Virginia, West Virginia
Secure (S5)                             Delaware, Kentucky, New Jersey, North Carolina
Not ranked (SNR)                        Alabama, Arkansas, Connecticut, District of Columbia, Florida,
                                        Georgia, Illinois, Indiana, Kansas, Louisiana, Maryland,
                                        Massachusetts, Michigan, Mississippi, Missouri, Ohio,
                                        Oklahoma, Pennsylvania, Rhode Island, South Carolina,
                                        Tennessee, Texas;
                                        Mexico: Nuevo Leon

                                                   5
Recovery Strategy for the Slender Bush-clover in Ontario

In Ontario, Slender Bush-clover is present only in the Ojibway Prairie Complex in the
City of Windsor. In that area, the species has been documented from three sites,
Tallgrass Heritage Park, Black Oak Heritage Park, and Ojibway Park, all of which
qualify as subpopulations of a single population or occurrence according to the criteria
used by the Natural Heritage Information Centre (NHIC 2012)1. All three sites are in
parks managed by the City of Windsor, Department of Parks and Recreation.

The species was first discovered at Tallgrass Heritage Park in 1977. Plants were
observed there in 1978, 1979, 1982, 1984 and 1997 but were not found in 2000 or 2011
(NHIC 2012). Abundance was not documented except in 1984 when approximately 150
plants were reported. In 2000, the site was reported to be too shaded-in and dense with
understory vegetation (NHIC 2012), and the loss of the Slender Bush-clover plants at
this site has been attributed to natural succession (COSEWIC 2012a).

In 1993, a single Slender Bush-clover plant was observed in Black Oak Heritage Park
along a walking trail. The site was visited in 1997 and 2011 but the species was not
found and may have been destroyed by all-terrain vehicles (ATVs) (COSEWIC 2000,
COSEWIC 2012a).

In 1979, Slender Bush-clover was discovered at Ojibway Park. The plants were not
found in 1984 for the first COSEWIC status report (Pratt 1986) but were observed and
documented in 1986, 1997, 2000 and 2011 (COSEWIC 2000, NHIC 2012). Abundance
of Slender Bush-clover at this site is shown in Table 2.

Table 2. Abundance of Slender Bush-clover at the Ojibway Park site (NHIC 2012)

Date                                Abundance                           Observers
1979                                ~50 plants                          P.D. Pratt
1984                                0                                   P.D. Pratt
1986                                "a few"                             M.J. Oldham
1997                                160                                 K. Cedar
2000                                >24                                 D. Jacobs, P.D. Pratt, P.A.
                                                                        Woodliffe & K. Cedar
2011                                165                                 S.R. Brinker, M.J. Oldham, C.D.
                                                                        Jones

Due to Slender Bush-clover's long-lived seed viability, it is possible the species may be
extant in the seed bank and could potentially reoccur at any of the three sites in the
Ojibway Prairie Complex even though live plants of Slender Bush-clover have only been
seen in recent years at the Ojibway Park site. Therefore, all three sites must still be
considered extant locations.

Only generalized conclusions can be made about population trends because the
populations have not been consistently observed, but overall there appears to be a

1
  All patches that occur within 1 km of each other are considered to belong to the same population or
occurrence. Patches at greater distance may also be included if there is no significant break or change in
the habitat. See NHIC (2012) for a detailed definition of occurrence.

                                                    6
Recovery Strategy
                               S        for th
                                             he Slender Bu
                                                         ush-clover in O
                                                                       Ontario

decline in
        i populatio
                  on size in th
                              he last 25 years.
                                         y       The loss of the plants at thhe Tallgrasss
Heritage
       e Park site, from 150 plants
                              p      in 1984 to 8 plannts in 1997
                                                                7 to 0 in 20111, likely du
                                                                                         ue to
successsion (COSE EWIC 2000)), is certainlly a decline
                                                     e. The loss of the plannts at Blackk
Oak Herritage Park, probably from
                              f    ATVs, is another decline. A  At the Ojibw
                                                                           way Park sitte,
the data
       a show man             ons and an overall slig ht increase
                  ny fluctuatio                                 e from the pprevious hig gh of
160 in 1997 to 165 in 2011 (NNHIC 2012).. However,, generally, the trend in the last 2   25
years in Ontario ap
                  ppears to bee one of deecline and ppossibly the
                                                                e loss of site
                                                                             es.

Historica
        ally, Slende
                   er Bush-clov ver was alsso present iin the Leammington area, where it was
collected
        d by Macou un in 1892 (NHIC
                                (      20122). Howeve  er, the popu ulation therre has neveer
been rellocated desspite many focused se  earches. Th  he area is nnow heavilyy urbanized  d or
converteed to agricu
                   ulture (Prattt 1986). In addition, th
                                                       here is a hisstorical report of Slend
                                                                                           der
Bush-cloover from th
                   he Niagara Region ma    ade by W. S Scott in 18996; howeve  er, the reporrt is
not backked up by a collected specimen
                                s          and
                                           a the reco  ord is considered likely an error
(COSEW  WIC 2000).

1.4    Habitat
       H       Ne
                eeds
In Canada, Slender Bush-clov   ver is restric
                                            cted to dry--mesic tallg
                                                                   grass prairie
                                                                               e relicts with
                                                                                            h
patches of exposed  d sandy soiil. In 2011, the Ontario  o habitat w
                                                                   was reported d to be sanddy
openings in oak wo oods with Little Blueste em (Schiza achyrium sccoparium), C  Crown Vetcch
(Securig
       gera varia), Black Oak (Quercus velutina),
                                            v          C
                                                       Canadian Tiick-Trefoil ((Desmodium   m
canaden nse), Feather Three-aw  wn (Aristidaa purpurasccens), Densse Blazing Star (Liatriss
spicata), and Spottted Knapwe  eed (Centau  urea stoebe  e) (NHIC 20 012). The Ecological
Land Claassification
                   n (ELC) veg getation typee (Lee et al. 1998) of tthe current Ontario
location is describe
                   ed as Dry Black
                               B      Oak Tallgrass
                                           T          Saavannah (T TPS1-1) (P.A A. Woodlifffe,
pers. comm. 2012) or possibly   y Dry Blackk Oak Tallgrrass Woodland (TPW 1-1) at the
sites wh
       here vegetation cover hash increas  sed and clo osed in mosst of the ope en area. AAs
the speccies occupiees the open n patches within
                                           w      these e vegetationn communitty types, it ccan
be assumed that DryD Tallgrass Prairie (T  TPO1-1) wo   ould also prrovide suitable habitat..
The speecies requirees full sun and
                                a open ground
                                           g        for e
                                                        establishme ent of seedllings and does
not appeear to be abble to grow in dense shade or witthstand eve    en moderatte levels of
competittion from suurrounding vegetation (Pratt 1986    6, COSEW WIC 2000). The openin    ng at
Ojibwayy Park wherre the speciies currently occurs is approxima    ately .33 ha.

The requ uirement foor open soil indicates that some tyype of distu urbance (su  uch as fire,
periodic drought orr anthropogenic disturb   bance) is neeeded for mmaintenancce of suitable
habitat conditions.
         c            Without it, the open ground
                                            g       wou uld be expected to beccome coverred
with thattch from a build-up
                     b        of leaves and d organic m aterials andd to fill in w
                                                                                 with vegetation
from nattural succes ssion, becooming unsuitable for S  Slender Bussh-clover. H   Historically,,
bare groound probab  bly resulted
                                d from fire but
                                            b now like  ely comes m mainly from  m other typees of
disturbance. Pratt (1986) repo   orts that at the Tallgra
                                                        ass Heritagee Park site,, Slender B  Bush-
clover plants were located in ana area where the gro    ound was sccraped. He    e adds that
1948 airr photos sho ow an open n trail a few
                                            w metres ea ast of where
                                                                   e the plantss were locatted,
so the trrail may also have previously provided some     e disturbance. Howevver, he also    o

                                                 7
Recovery Strategy
                               S        for th
                                             he Slender Bu
                                                         ush-clover in O
                                                                       Ontario

reports that
        t    spring fires burned through the area in 1978, 1980  0 and 1983 and occurrred
within 10
        00 m of thee population
                              n in 1976, 1977 and 19984, so it iss possible th
                                                                             hat fire help
                                                                                         ped
maintainn the opennness of the area during
                                         g the time t hat the habbitat remain
                                                                            ned suitablee.

The freqquency at which
                    w     disturbance is re equired, or tthe time peeriod over wwhich the
habitat may
        m becom    me too heav vily vegetateed to be suitable, is un nknown. Acccording to   o
Pratt (19
        986), the sccrape at Tallgrass Herritage Park probably da     ated from a around 1958,
and was s therefore roughly 26 years old in 1986. Be     etween 197  75 and 1986  6, Pratt
observed little appaarent chang ge in the sitte, indicatin
                                                         ng a very sloow rate of ssuccession,
especiallly in the ce
                    entre of the scraped arrea, during that nine-yyear period. This was also
a periodd in which fire and humman disturba  ance were occurring ssporadicallyy. By 1997,
there waas almost non open min  neral soil prresent (COS  SEWIC 200  00) and onlly eight Slender
Bush-cloover plants were found  d. Thus, it appears the   e habitat beecame sign  nificantly
degrade ed in the 13 years betw ween 1984 and 1997. It can be sspeculated that fire or
disturbance may be   e needed every
                               e      3 to 13 years, an  nd probablyy closer to the more
frequentt end of thaat range since plants had nearly d   disappeared  d after 13 yyears.

Optimal habitat for Slender Bu    ush-clover contains
                                              c        a sspecific asssociation off prairie forbs
(Pratt 19  986), but sppecies composition in the habitat has probab   bly changed somewha     at in
the last 25 years, possibly
                       p       indicating an overall
                                              o      degradation. P  Pratt (1986)) listed 12
species frequently associated with Slend     der Bush-cloover and 12  2 rare speccies (based on
Argus an    nd White 19 977, 1982 and
                                  a 1983, and a Argus a  and Keddy 1984) that were found       d
within 1 m of Slend    der Bush-clo
                                  over. Of these, only twwo of the foormer frequuent associa   ates
and only   y three of th
                       he former ra
                                  are speciess were pressent in 2011 1 (COSEWIC 2012a).
Still, it is
           s possible th
                       hat some of
                                 o this differe
                                              ence may bbe due to th he reduction n in the num mber
of sites as a well.

COSEW   WIC (2012a)) listed 34 plant
                               p     speciees growing within 1 m of Slender Bush-clove     er
during fieldwork in Septemberr of 2011. Most
                                           M     are prrairie-obliga
                                                                   ates or speccies of old
fields. One
        O of these e, Dense Bllazing Star (Liatris spiicata) is fedderally and provinciallyy
listed as
        s Threateneed, and threee are listed
                                           d as rare in Ontario: AArrow Feath her Three-awn
(Aristida
        a purpurasccens – S1), Tall Coreopsis (Coreo   opsis tripterris—S2), annd Round-
fruited Panic
        P     Grasss (Dicanthelium sphae  erocarpon— —S3) (COSE    EWIC 2012  2b, NHIC 20  012).

        gan, Slende
In Michig           er Bush-cloover is found in 17 cou  unties in habitats that iinclude dry
open wo oods (espec cially oak), prairies, sh
                                            hores, fieldss, railroad b
                                                                     banks and oopen hills
(Voss 19985, Reznic cek et al. 20
                                011). It is unknown
                                            u          w
                                                       why the speccies occurss in more
locations
        s and in a wider
                    w      range
                               e of habitatss in Michiga an than in OOntario. Th
                                                                               hroughout itts
global ra
        ange, the species is no ot restricted
                                            d to sandy ssoils, and inn some staates the speecies
is found at latitudes
                    s more norttherly than Windsor.

1.5    Limiting
       L        Factors
                F
In Ontarrio, Slenderr Bush-clover is extremmely limitedd by a lack o
                                                                   of suitable habitat. Off the
hundredds of square e kilometres
                               s of tallgras
                                           ss prairie annd savannaah documen   nted in earlly

                                                 8
Recovery Strategy
                               S        for th
                                             he Slender Bu
                                                         ush-clover in O
                                                                       Ontario

settleme ent times, only
                     o     about 2100
                                 2     ha or 0.5%
                                              0    rema ains, with the majority llost to
agricultuural use and d residentia
                                 al developmment (Bakow  wsky and R Riley 1994).. Today, appart
from thee Ojibway Prairie
                     P       Complex and arreas on Wa   alpole Islandd, most rem
                                                                               mnant patchhes
are sma all (less thann 2 ha) andd isolated. Natural
                                              N       eco
                                                        ological proocesses, such as the
occurren nce of wildffire, are sev
                                 verely comp promised inn such small patches. Suitable
prairie habitat
        h        for Slender
                     S        Bussh-clover is highly frag
                                                        gmented intto small pattches that a
                                                                                          are
isolated from one another
                     a         by distances
                                  d         of
                                             o hundredss of metres or more. T  This probabbly
limits the
         e ability of Slender
                      S        Bush-clover too expand innto new are eas (COSEW    WIC 2000).

Mature fruiting
        f        plan
                    nts of Slendder Bush-cloover producce only a fe
                                                                  ew hundred  d seeds, wh hich
may redduce the rep productive capacity
                                 c        of the speciess (COSEWWIC 2000). In addition,,
these seeeds require e scarification before they
                                            t    can geerminate annd the natural factors
which hiistorically may
                    m have prrovided this  s process (ssuch as fire
                                                                  e, specific tyypes of animal
vectors, etc.) may now
                    n    be unc common or no longer o  occur. Low w reproducttive capacity is
not an in
        nherent limitation in the genus sin nce some sspecies of bbush-cloverrs, such as
Silky Bu
       ush-clover (Lespedeza    a cuneata) are
                                            a invasive e on rangelland (Blockksome 2006   6).

It is posssible that th
                      he climate of
                                  o Ontario, the
                                             t northerrn part of thhe species rrange, mayy be
a limitatiion to Slendder Bush-cllover. The species flo owers at thee end of the e summer aand
must set seed befo    ore the end of the grow
                                            wing season  n. This time frame is sshorter in
Ontario than it is in the core of the specie es' range in
                                                        n the centraal Midwest, and probab  bly
occasion nally resultss in low or lost
                                  l    seed se
                                             et in years when there e is early fro
                                                                                 ost or snow
                                                                                           wfall.

Finally, the
         t populattion of Slender Bush-c clover in Caanada is very small and isolated a  and
thus at risk
        r of being g destroyedd by a single stochastic event, su uch as a floood or wind
storm. A severe sttorm wiped out a popu  ulation that had been p planted in LLambton Co ounty
as part of
         o an experrimental res
                              storation (R
                                         R. Ludolph, pers. comm  m. 2012). A single eve  ent
could remove the entire
                  e      popullation, espe
                                         ecially since
                                                     e the live pllants curren
                                                                             ntly occupyy an
area of only
         o   9 by 4 m (COSEW  WIC 2012a).

1.6    Threats
       T       to
                o Surviva
                        al and Rec
                                 covery

Observe ed Threats
Altered Disturbance
         D           e Regime
The mos  st serious current
                    c       threat to Slender Bush-clo over is degrradation or loss of hab   bitat
from fire
        e suppressio on or otherr changes too the naturaal disturban
                                                                   nce regime. Without
disturbance of som me type, nattural succes ssion takess place and open areas fill in with
vegetation, coverin ng up the oppen ground required fo  or germinattion and groowth. Slender
Bush-clo over does not
                    n compete    e well with surroundingg vegetatioon, so the in
                                                                               ncreased co   over
of other plants is a serious detriment thatt can ultimaately lead too a complette decline a  and
         he population. Degrad
loss of th                       dation of ha
                                            abitat contin
                                                        nues to be an active th hreat despiite
all three locations for
                    f the spec  cies being in protectedd, managed  d parks. Th he filling in o
                                                                                             of
vegetation is likely the main faactor responsible for thhe lack of g
                                                                   growing plants and
possible            e Tallgrass Heritage Park populattion (COSE
        e loss of the                                              EWIC 2012a   a).

                                                 9
Recovery Strategy
                                S        for th
                                              he Slender Bu
                                                          ush-clover in O
                                                                        Ontario

       c burning is conducted within the Ojibway Prrairie Comp
Periodic                                                           plex and all three sitess for
Slender Bush-clove  er have bee en burned occasionally
                                            o           y in the passt with enouugh intensitty to
remove leaf litter and blacken soil. Howe   ever, the fre
                                                        equency off burns has been low in
Ojibwayy Park and Tallgrass
                    T          Prairie Herita
                                            age Park (P P.D. Pratt, p
                                                                    pers. comm m. 2012).
Whetherr due to loww intensity, low frequen ncy or a coombination, it appears that the
burning done was insufficient
                    i            to maintain
                                           n the habitaat at the Talllgrass and Black Oakk
Park site
        es. Lack off fire or othe
                                er disturbannce contributes to hab bitat loss byy allowing a
build-up of leaves and
                    a organic   c materials (dead plan nts and grasss) to coverr patches o of
exposed d soil.

Invasivee Species
Crown Vetch
        V     (Secu urigera variia), Autumn
                                          n Olive (Ela eagnus um
                                                               mbellata) an nd Spotted
Knapwe  eed (Centau urea stoebee ssp. micraanthos) are
                                                     e present wiithin 1 m off Slender Bush-
clover plants (COS SEWIC 2012    2a). These
                                          e non-native          have the capacity to
                                                      e species h
spread quickly,
         q       take over open ground and eliminatte most othe  er surroundding plant
species.. None of these species is mentioned by Prratt (1986) o  or COSEW  WIC (2000),
indicatin
        ng that theirr presence is a recent occurrencee.

Crown Vetch
        V        formss a low grouund cover that carpetss open sand     d. Because   e it spreadss
quickly and
         a has ten    nacious roo ots, it is freq
                                                quently plan
                                                           nted in highhway constrruction projects
to preveent erosion. According    g to COSEW    WIC (2012a a), in 2011 tthis speciess had alrea   ady
succeed ded in covering up mos      st of the oppen sand paatches in thhe small pra  airie remnant
where Slender
        S          Bus
                     sh-clover is found. Spotted Knap      pweed is kn nown to be h   highly invassive
due to itts allelopathhic effects (secreting
                                   (            to
                                                 oxins from its roots intto the soil). It was liste
                                                                                                  ed as
rare in th
         he vicinity of
                      o the Slend  der Bush-clover plantss. Autumn Olive is a fa      ast-growing g
woody species
        s          thatt is presentt in the habitat. It has the capacitty to grow ttall and sha   ade
out shorrter plants.

Historica
        al threats
In the pa
        ast, ATV an nd dirt bike use occurrred near the    e Canadiann Slender Bush-clover
subpopu ulations (Prratt 1986). All-terrain vehicle
                                             v         usee can be a tthreat if it da
                                                                                    amages or
breaks plants
        p       and causes
                     c       rutting and dissplacement of soil. Ho    owever, distturbance fro om
ATVs prrobably also  o contribute
                                ed to mainta  aining the e exposed gro ound the sp  pecies
requiress. All terrain
                     n vehicles and
                                a dirt bike   es are no lo onger permmitted in the protected
parks wh here Slender Bush-clo  over occurs  s. This has eliminated the threat of damage      e to
Slender Bush-clove   er plants bu
                                ut it has also removed a factor tha    at helped to o maintain
suitable habitat in the
                     t absence   e of naturall disturbancce. Reinsta  ating ATV u  use is certainly
not reco
       ommended, but the iss    sue is mentioned here to show that light leve       els of some
                                                                                              e
types off human dis sturbance may
                                m be bene     eficial, altho
                                                           ough strikin
                                                                      ng the corre  ect balance
                                                                                              e
where no harm is done
                    d      may be
                                b difficult.

1.7    Knowledg
       K      ge Gaps
Whetherr Slender Bush-clover
                 B           is still pres
                                         sent and via
                                                    able in the sseed bank at Tallgrasss
and Blac
       ck Oak Herritage Parks
                            s is a knowledge gap tthat must b  be filled in o
                                                                            order to kno
                                                                                       ow if

                                                  10
Recovery Strategy
                               S        for th
                                             he Slender Bu
                                                         ush-clover in O
                                                                       Ontario

these tw
       wo sites (wh  here live Sleender Bush  h-clover plants have no  ot been see
                                                                                 en recently) still
require recovery
        r           effforts. In ad
                                  ddition, the processes needed to allow Slender Bush-
clover plants to be successfully re-establlished from the seed b      bank are noot known.
Researcch to fill these gaps ge   enerally requires takingg soil coress and germiinating all
seeds present in a controlled environmen      nt.

Many otther knowle edge gaps need
                               n     to be filled
                                           f      to guid
                                                        de recoveryy for the Ojjibway Parkk
occurren
       nce and possibly for th he other twoo sites. These include  e limited unnderstanding of:
    thhe viability of
                    o the occurrence;
    thhe frequenc cy and intennsity of burning that co ould be benneficial for h
                                                                                habitat
      maintenance
      m             e and improovement;
    productivity (i.e., amount of seed sets and effe   ects of wea
                                                                  ather);
    seed viability y and germmination rate
                                          es;
    genetic uniq  queness and d possible effects
                                           e        of in
                                                        nbreeding;
    availability of
                   o pollinators and degre ee of reliannce on self-fertilization versus cro
                                                                                          oss-
      pollination;
    current rates  s and distan
                               nces of seeed dispersa  al and availa
                                                                   ability of an
                                                                               nimal vectorrs;
      and
    thhe severity of the threaat from inva
                                          asive specie  es as well a
                                                                   as the mechanism of tthe
      th
       hreat (e.g., shading, coompeting foor pollinatorrs, allelopathy, etc.).

The locaation and heealth of any y transplantted occurre
                                                       ences would
                                                                 d also be useful to kno
                                                                                       ow
to assistt with poten
                    ntial future restorations
                                 r          s.

1.8    Recovery
       R        Actions Completed or Underway

All subpopulations of Slender Bush-clove  er are within n parks tha
                                                                  at are manaaged by thee City
of Windssor. No mo otorized vehhicles are allowed,
                                          a         so the threat oof damaged d or broken
                                                                                        n
plants and habitat degradation
                    d          n from ATV Vs and dirt bbikes has bbeen eliminaated. In
addition, controlled
                   d burning is done in Ojibway Parkk, Tallgrass Prairie Heritage Parkk,
Ojibwayy Prairie Pro
                   ovincial Natture Reservve, and Sprring Garden   n Natural Area, althoug
                                                                                         gh
the frequ
        uency and intensity off burning in Slender Bu  ush-clover habitat probbably needs to
be adjussted to ensuure burning
                              g actually coontributes tto the on-gooing mainteenance of
suitable habitat andd possibly provides
                               p         ne
                                          ew areas foor colonizatiion. Invasivve Crown
Vetch annd Autumn Olive have  e been remo  oved period dically by hand at the Ojibway Pa ark
Slender Bush-clove er site (P.D. Pratt, pers
                                           s. comm. 22012).

In 2005, the Tallgra ass Recove ery Team produced the   e draft Natiional Recovvery Strateg  gy
for Tallg
        grass Comm  munities of Southern
                                  S         Ontario
                                            O       and Associated  d Species a at Risk
(Ambros se and Waldron 2005)). The overrall goal of tthe plan wa  as to recove  er, reconstrruct,
and conserve a rep  presentative e network of
                                            o tallgrass communitie  es, along wwith the full
complem ment of plan nt and animmal species that inhabiit these diveerse ecolog gical
commun  nities. This strategy co  overed 1388 plant speccies and 45
                                                                  5 animal spe  ecies that a are
rare or at
        a risk, all off which are restricted to
                                             t or assocciated with ttallgrass eccosystems.
Slender Bush-clove   er is one off these speccies. While
                                                       e most recoovery effortss have sincce

                                                11
Recovery Strategy for the Slender Bush-clover in Ontario

shifted to working on species individually, this plan brought a lot of attention to the
benefits of recovering the ecosystem as a whole in order to improve the situation for
many species together. There are still several multi-species recovery plans being
developed and implemented from this group of species.

From 1985 to at least the mid-1990s, Slender Bush-clover was grown in gardens at the
Ojibway Nature Centre using seeds from the Tallgrass Park site (COSEWIC 2000, R.
Ludolph, pers. comm. 2012). The plants were planted out by the Rural Lambton
Stewardship Network as part of restoration work in the historical range of tallgrass
prairie. However, the main location where plants were successfully growing was
destroyed in a storm and information on any other locations has been lost. The species
is reportedly easy to grow and is good for attracting wildlife (R. Ludolph, pers. comm.
2012). A few plants still survive in the garden at the nature centre (P.D. Pratt, pers.
comm. 2012).

The Ojibway Prairie Complex, which consists of several parks, has been well studied
and botanized, so the area is well known and has been searched intensively without
finding additional sites for Slender Bush-clover. Furthermore, many other Ontario
prairie sites have also been well studied and searched for species at risk, and Slender
Bush-clover has not been found. This includes Walpole Island (Walpole Island Heritage
Centre 2006). The species also has not been found during new field work in the
corridor of the Detroit River International Crossing (Canada-U.S.-Ontario-Michigan
Border Transportation Partnership 2009), in which several new populations of other
species at risk have been discovered (G.E. Waldron, pers. comm. 2010, P.A. Woodliffe,
pers. comm. 2010). Thus, it is rather unlikely that additional populations of Slender
Bush-clover will be found.

                                               12
Recovery Strategy
                                 S        for th
                                               he Slender Bu
                                                           ush-clover in O
                                                                         Ontario

2.0     RECOVER
        R     RY

2.1     Recovery
        R        Goal

The reco overy goal is to mainta
                               ain the abundance and  d distributio
                                                                  on of growinng plants off
Slender Bush-clove er at Ojibwaay Park at current
                                          c       or g
                                                     greater leve els by reduccing threatss,
and if the species is extant in the seed ba
                                          ank at the oother two subpopulatio  ons, to
increasee the numbe er of growin
                               ng plants present therre to pre-19995 levels.

Rationalle for Recov very Goal
First, two of three known
                    k        subp
                                populations s of Slenderr Bush-clovver appear tto have bee en
lost to habitat degraadation. Th herefore, re
                                            ecovery mu ust focus onn maintaininng the last
remainin ng location where live,, growing plants of thee species arre present. Second, th  he
known historical
         h         dis
                     stribution off Slender Bush-clover
                                            B           r in Canadaa includes oonly the
Ojibway y Prairie Complex in Windsor
                               W         and a site nearr Leamingto on where th he species has
not been n seen sincce 1892. Th  herefore, re                      maintaining the current
                                            ecovery willl focus on m
distribution in the Ojibway
                    O         Pra
                                airie Comple ex. Finally,, whether th
                                                                    here is a via
                                                                                able seed bbank
of Slendder Bush-clo over has too be determined before  e recovery ccan be con nsidered forr
Tallgrass and Black  k Oak Herittage Parks..

Given thhe small population siz  ze and extre emely limite
                                                         ed distributtion, it is unlikely that
recovery y will ever result
                     r      in dow
                                 wnlisting off this specie
                                                         es. Still, ha
                                                                     alting habitaat loss may
result in stable or even
                     e     somew what expanded popula    ations which h might req quire less
attentionn to ensure their persisstence.

2.2     Protection
        P        n and Rec
                         covery Objectives
                                O        s
To meett the recoveery goal, the
                               e protection
                                          n and recovvery objectiives for Sle
                                                                            ender Bush--
clover are as follow
                   ws:

Table 3. Protection
                  n and recov
                            very objectives

  No.   Protection
        P          or Recovery Ob
                                bjective
   1    Maintain
        M        or im
                     mprove habita
                                 at suitability att the three ex isting sites.

   2    Reduce
        R      prese
                   ence of invasive species att the three exxisting sites.

   3    Fill
        F knowledge
                  e gaps.

   4    Increase popu
                    ulation size an
                                  nd extent if de
                                                eemed feasib
                                                           ble.

Note tha
       at the know  wledge gap regarding the seed ba  ank must be
                                                                e filled (Objective 3)
before itt will be kno
                     own if Objec
                                ctives 1, 2, and 4 shou
                                                      uld be applied to the T
                                                                            Tallgrass an
                                                                                       nd
Black Oak Heritage   e Park sites
                                s.

                                                      13
Recov
                                                   very Strategy for the
                                                                     t Slender Bush
                                                                                  h-clover in Ontarioo

2
2.3     Appro
            oaches to Re
                       ecovery
T
Table 4. Appro
             oaches to reco
                          overy of the Slender Bush-clover in Ontario
                                                                    o.

                                                                                                                         Threats or
       Relative      Relative        Recovery
                                                                      Approach
                                                                      A        to Recovery                             K
                                                                                                                       Knowledge Gaps
                                                                                                                                    s
       Priority     Timeframe         Theme
                                                                                                                         Addressed
      1. Maintain
                n or improve habitat suitability at the three existing sites.
        Critical    Short-term Management
                               M                     1.1 Assess type of habitat improv vement actions thhat are  Habita
                                                                                                                       at degradation orr loss
                               and                       needed and appropriate for each
                                                                                      e     of the three ssites.
                               Stewardship
                               S                         These may include burning, cutting
                                                                                       c       back vegeetation,
                                                         scraping, rak
                                                                     king or other actio
                                                                                       ons.
        Critical    Short-term Management
                               M                     1.2 Assess potential positive or negative
                                                                                      n        impacts oon       Habita
                                                                                                                       at degradation orr loss
                               and                       other rare sp
                                                                     pecies present in the same habitatt from
                               Stewardship
                               S                         habitat impro                 f Slender Bush -
                                                                     ovement actions for
                                                         clover.
        Critical      Ongoing     Management
                                  M                  1.3 Plan and exe ecute appropriate
                                                                                      e actions to improove      Habita
                                                                                                                       at degradation orr loss
                                  and                    habitat at ea
                                                                     ach site.
                                  Stewardship
                                  S                      -- Search forr partners and vo
                                                                                      olunteers to help w
                                                                                                        with
                                                         labour.
      Necessary       Ongoing     Monitoring
                                  M          and     1.4 Monitor resu
                                                                    ults of 1.3.                                 Habita
                                                                                                                       at degradation orr loss
                                  Assessment
                                  A
      Necessary       Ongoing     Management
                                  M               1.5 Based on 1..4, plan next actio
                                                                                   ons. Consider                 Habita
                                                                                                                       at degradation orr loss
                                  and stewardship     frequency an
                                                                 nd intensity at wh
                                                                                  hich action is requuired.
      2. Reduce
              e presence of inva
                               asive species at the
                                                t three existing sites.
      Critical      Short-term    Management
                                  M                  2.1 Assess best method to reduc   ce presence of thee        Invasiive species
                                  and                    invasive spe ecies for each of the three sites. C
                                                                                                         Consult
                                  Stewardship
                                  S                      current litera
                                                                      ature for best mannagement practicces.
      Critical      Short-term    Management
                                  M                  2.2 Assess potential positive or negative
                                                                                      n        impacts oof       Invasiive species
                                  and                    invasive speecies removal on other
                                                                                       o    rare speciees
                                  Stewardship
                                  S                      present in the same habitat.

                                                                           14
Recovery Strategy for the Slender Bush-clover in Ontario

                                                                                                              Threats or
 Relative     Relative       Recovery
                                                             Approach to Recovery                           Knowledge Gaps
 Priority    Timeframe        Theme
                                                                                                              Addressed
Critical     Short-term   Management        2.3 Plan and execute appropriate actions to reduce         Invasive species
                          and                   invasive species presence.
                          Stewardship           -- Search for partners and volunteers to help with
                                                labour.
Necessary     Ongoing     Monitoring and    2.4 Monitor effects of 2.3.                                Invasive species
                          Assessment
Necessary     Ongoing     Management        2.5 Based on 2.4, plan next actions. Consider frequency  Invasive species
                          and                   and intensity at which action is required.
                          Stewardship
3. Fill knowledge gaps.
Critical     Ongoing      Research          3.1 Plan and conduct research on seed bank of Slender      Whether a viable seed bank
                                                Bush-clover.                                            is present
                                                -- Search for partners to conduct research.            How to bring Slender Bush-
                                                                                                        clover back from seed bank
Beneficial   Long-term    Research          3.2 Plan and conduct research on other knowledge           Population viability and
                                                gaps as funding and partners become available.          productivity
                                                                                                       Seed viability and
                                                                                                        germination
                                                                                                       Genetics
                                                                                                       Pollinators
                                                                                                       Dispersal rates and
                                                                                                        distances
                                                                                                       Severity of threats
                                                                                                       Location and health of
                                                                                                        transplanted populations
4. Increase population size and extent if deemed feasible.
Necessary    Long-term    Management        4.1 Establish new populations as feasible to prevent       All threats
                                                extirpation of the species due to stochastic events
                                                and as a precaution in case of failure to manage
                                                current threats.

                                                                 15
Recovery Strategy for the Slender Bush-clover in Ontario

                                                                                                         Threats or
 Relative     Relative     Recovery
                                                        Approach to Recovery                           Knowledge Gaps
 Priority    Timeframe      Theme
                                                                                                         Addressed
Beneficial   Long-term   Management     4.2 Pending outcome of 1.4, conduct recovery actions to  Limiting factor: small
                                            increase presence of Slender Bush-clover at all       population.
                                            three sites.
Beneficial   Long-term   Management     4.3 Pending outcome of 3.1, conduct recovery actions to  Limiting factor: small
                                            increase presence of Slender Bush-clover from seed    population.
                                            bank.

                                                            16
Recovery Strategy
                               S        for th
                                             he Slender Bu
                                                         ush-clover in O
                                                                       Ontario

Narrative to Support Approach   hes to Recoovery
All recovvery actions for Slender Bush-cloover need to o be carefu
                                                                 ully assesse ed and plannned
before being
       b       carried out. This
                               s is to ensure that actio
                                                       ons do not harm the e  existing smaall
population of Slend der Bush-clover or any y of the othe
                                                       er species at risk or ra
                                                                              are speciess that
are pressent in the same
                     s     habita
                                at.

Howeve er, most other species present wo   ould probab                         onal clearing
                                                       bly benefit ffrom additio
and opeening up of the habitat (P.D. Prattt, pers. commm. 2012, S  S.R. Brinker, pers. com mm.
2012), and
        a staff at Ojibway Prrairie are already takin  ng care to p
                                                                  protect fire-ssensitive
species at risk during burning (P.D. Prattt, pers. commm. 2012). However, best
manage ement practtices (BMPs s) for invasive-speciess control alsso need to be conside   ered
during re
        ecovery woork to keep invasives from being ffavoured byy habitat cle    earing. To
prevent spreading the invasivees, it is like
                                           ely that seve
                                                       eral types oof recovery actions wo ould
need to be done in combinatio on (for exam  mple, burning followed  d by herbiciide use, or
clipping of shrubs followed
                   f        by burning).

Althoughh the Canadian popula    ation is veryy small, witth recovery actions, the prognosiss for
Slender Bush-clove  er could be very positive. In Illino  ois, efforts tto recover a similar
species,, Prairie Bush-clover (L Lespedeza  a leptostachhya—threattened in the    e U.S.), havve
includedd the use off fire, herbic
                                 cide and gra azing by bisson to redu uce compettition from
grasses and other plants. Pre    eliminary annalyses sho  ow these tre  eatments hhave resulteed in
an increase in seed dling production, an increase in n   number of in   ndividuals o
                                                                                   overall, and
                                                                                              d in
plants th
        hat are morre robust (P P. Vitt, pers.. comm. 20012, Chicag   go Botanic G Garden 201 12).

As a preecaution, it would
                     w      be beneficial to
                                           o establish ssome plantings of Slen  nder Bush-
clover in
        n locations separate
                     s         fro
                                 om the currrent patch tto ensure th
                                                                   hat the spe ecies is not
extirpate
        ed in case of
                    o an accide  ental event, such as a storm. Th he few plantts in the gaarden
bed at th
        he Ojibway Nature Ce    entre could be augmen  nted to ensuure a stable e garden
population. Slende  er Bush-clover is listed
                                           d on Schedule 1 of the  e ESA as en  ndangered only
within Olibway
       O         Parkk, Black Oaak Heritagee Park and T Tallgrass H
                                                                  Heritage Park, so the
plants would
       w      not haave legal prrotection els
                                            sewhere. T  Therefore, it might be advisable tto
establish
        h an additioonal restoraation populaation somew where within one of th hese parks to
ensure the
        t plants would
                    w      be prrotected. Relocation
                                           R           o
                                                       of the restorration sites where the
species was plante  ed in Lambtton County would also  o be beneficcial to see iff any restorred
populations of Slen nder Bush-c clover havee survived.

2.4    Area
       A    for Considera
                C       ation in Developin
                                 D       ng a Habiitat Regulation

Under thhe ESA, a recovery
                   r          strrategy mus st include a recommen   ndation to th
                                                                                he Minister of
Natural Resources on the area that shou     uld be consiidered in de eveloping a habitat
regulatio
        on. A habita
                   at regulation n is a legal instrumentt that presccribes an arrea that willl be
protecte
       ed as the haabitat of the
                               e species. The
                                            T recomm    mendation p  provided beelow by thee
author will
       w be one of  o many sou   urces cons sidered by th
                                                        he Ministerr when deve  eloping the
habitat regulation
        r          for
                   fo this spec cies.

                                                17
Recovery Strategy for the Slender Bush-clover in Ontario

In establishing the area to be prescribed as habitat in a regulation, several
considerations need to be mentioned.

First, although seeds of Slender Bush-clover are known to remain viable for decades, it
is unknown whether Slender Bush-clover is still viable in the seed bank at the Black Oak
and Tallgrass Heritage Park sites. Therefore, it is recommended that all sites where
Slender Bush-clover has been observed in the Ojibway Prairie Complex come under a
habitat regulation even if no live plants are present, until this knowledge gap is filled or
until a 50-year time limitation has passed (see #4 below).

Second, the habitat of Slender Bush-clover must have periodic disturbance in order to
remain suitable. This disturbance may come from several different types of activities or
processes including some types of human usage. Therefore, it is recommended that
legal regulation and protection of habitat should not cause the exclusion of all human
activities from the regulated area.

Third, the current habitat of Slender Bush-clover occurs within the recognizable ELC
types, Dry Black Oak Tallgrass Savannah or Dry Black Oak Tallgrass Woodland.
However, suitable habitat is only some small open patches within the savannah or
woodland matrix, so the habitat required is much smaller than the entire ELC vegetation
type polygon. Thus, ELC vegetation type is not a precise enough guide to prescribe
habitat.

Finally, although dispersal habitat is an important consideration for recovery, for Slender
Bush-clover it is not possible to base the size of the habitat to be prescribed on
dispersal distances. Dispersal in animal or bird feces is unpredictable, and the
distances covered by these vectors may be quite large, even on the order of kilometres.

Therefore, it is recommended that habitat be prescribed as follows:

1) At Ojibway Park, where live Slender Bush-clover plants continue to be observed, it is
recommended that the regulated habitat include the entire opening in which the plants
occur, as well as a protective zone of 50 m around the outside of the open area,
including any disturbed, human-made components such as scraped areas since light
soil disturbance may be helpful to the species. Should any suitable openings extend
beyond the 50 m, it is suggested that all of this open area also be prescribed. For this
prescription, "open" or "opening" may be defined as the area in which total tree cover is
less than 25 percent, with ground dominated (greater than 50%) by herbaceous plants,
shrubs or exposed soil, and not shaded by trees. These criteria are consistent with the
ELC characteristics of tallgrass prairie and cultural meadow (Lee et al. 1998). The
boundaries of the opening at Ojibway Park would be the point at which tree cover
becomes continuous and the ground too shaded. The exact boundary line of the
Ojibway Park opening is probably best assessed and mapped in the field.

A distance of 50 m has been shown to provide a minimum critical function zone for the
maintenance of microhabitat properties, such as light, temperature, litter moisture, vapor

                                               18
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