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File: Grasslands Southern Interior
ms h ecosyste in britis columbia t riskt risk aa grasslands of the southern interior grasslands cover less than one percent of british columbia s land area ministry of sustainable ...

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                                                                                 MS
                                                                                  H
                                                                        ECOSYSTE
                                                                         IN BRITIS
                                                                         COLUMBIA
                                                                                T RISKT RISK
                                                                              AA
                                                                     Grasslands
                                                                              of the
                                                                        Southern
                                                                           Interior
                                                                                Grasslands 
                                                                             cover less than 
                                                                             one percent of
                                                                         British Columbia’s
                                                                                land area.
             Ministry of Sustainable Resource Management
             Ministry of Water, Land and Air Protection
                                                            plants can go unnoticed, and reversing       of cheatgrass may result in too fre-
                                                            such changes can be difficult. People        quent, too intense fires in some 
                                                            often recreate in grasslands, without        valley-bottom grasslands.
                                                            realizing that the fragile, easily dis-
               Why are grasslands of the                    turbed crust of lichens, mosses, and         What are they?
               southern interior at risk?                   algae (known as a microbiotic crust),           rasslands of the southern interior are
                 n the hot, dry regions of the southern     soils, and plants are easily damaged by         semi-arid ecosystems dominated by
                 interior of British Columbia lie grass-    both motorized vehicles and mountain            bunchgrasses, shrubs, and non-grass
                 lands dominated by bunchgrasses,           bikes.A single track can become an              plants known as forbs. Grasslands
                                                                                                         G
               Iwildflowers, and dryland shrubs.            erosion site, become weed infested, and      occur in the hottest, driest valleys,
               Grasslands were naturally limited in         invite further traffic. Expansion of         including the Okanagan, Thompson,
               extent when European settlement began        urban and suburban populations also          Nicola, Fraser, Chilcotin, Kettle, and
               in the mid-1800s, and significant areas      brings more pets and recreation, which       Kootenay, and represent the northern
               of grasslands have been lost since that      can in turn negatively affect grasslands     extent of grasslands that once dominat-
               time. Today, grasslands cover less than      and the creatures reliant on them.           ed what are now agricultural fields of the
               one percent of British Columbia’s land          Southern Interior grasslands have a       Great Basin in the United States.
               area and are one of Canada’s most            long history of intensive livestock graz-       These valleys lie in the rainshadow
               endangered ecosystems. Scattered grass-      ing,which reduced many low-elevation         of the Coast, Cascade, or Columbia
               lands also occur in coastal, central, and    and gently sloping grasslands to little      mountains, where winters are cool or
               northern British Columbia; these grass-      more than bare soil in the early 1900s.      cold with relatively little snow.Valley
               lands are also threatened but have differ-   Many grasslands have partially or whol-      heating and a flow of warm air from 
               ent ecological characteristics from          Grasslands          ly recovered through     the Great Basin result in hot,dry sum-
               those in the southern interior.                                  carefully managed        mers. In this semi-arid environment,
                  The warm climate and dra-                 are the most        livestock grazing.       long summer droughts can prevent 
               matic setting of grassland ecosys-           valuable to         However, unman-          tree seedlings from establishing. Most
               tems has long attracted human                                    aged livestock graz-     grasses, however, are well-adapted to
               habitation, and today the loss of            biodiversity,       ing has degraded or      capturing limited moisture.The shape
               grasslands is evidenced by exten-            the most            prevented the recov-     of bunchgrasses funnels moisture to 
               sive vineyards,orchards,hay fields,                              ery of other grass-      a vast network of fine roots that are 
               human settlements, and commer-               fragile to          lands by exposing        particularly effective at capturing mois-
               cial and industrial developments             disturbances. mineral soil, dam-             ture near the soil surface. Bunchgrasses
               in southern interior valleys.About                               aging bunchgrasses,      survive drought by actively growing
               one-third of the grasslands area in                              and promoting the        only during spring and late autumn.
               the Okanagan Basin and Boundary              invasion of introduced plant species.           Although bunchgrasses characterize
               District has been lost to development;          Historically, natural fires main-         grasslands, some shrubs and a great
               the North Okanagan has lost nearly           tained grasslands on moister sites and       diversity of forbs also occur. In spring,
               half of its native grasslands. Ongoing       at higher elevations by preventing trees     moist soils bring the first flush of
               population growth will add increasing        from establishing. For about a century,      blooms of easily overlooked sage-
               pressures to remaining grasslands. Most      fire has been largely excluded from          brush buttercup and yellow bells,
               of the losses and adverse effects are to     grasslands through fire suppression,         which are soon followed by the bright
               valley-bottom ecosystems, which are          cessation of burning by aboriginal  pink and yellow splashes of bitterroot
               the most valuable to biodiversity, the       peoples, and removal of fine fuels           and arrow-leaved balsamroot. The
               most fragile to disturbances, and the        through domestic grazing. Subsequent         sequence of flowering continues until
               slowest to recover.                          forest invasion has reduced some             the hot, dry months of summer,
                  Many remaining grasslands have            Cariboo-Chilcotin grasslands by more         when the flashy colours of flowers are
               been invaded by introduced plants            than 30 percent since 1962. Although         replaced by the subtle beauty of tawny
               such as knapweed,sulphur cinquefoil,         not well documented, significant areas       tones and textures of dormant grasses
               and cheatgrass. Since grassland species      of many other grasslands have also           and plants. Fall brings the wind-polli-
               are subtly different and often poorly        been lost. Ironically, as has happened       nated flowers of big sagebrush and
               known,changes from native to foreign         in the United States, the introduction       rabbit-brush shrubs. This diversity of
                                                                                                                         and site conditions, including aspect                                      mo
                                                                                                                         and slope. In general, moisture, forb                                      val
                                                                                                                         diversity, productivity, and plant and                                     Co
                                                                                                                         litter cover increase with elevation,                                      gre
                                                                                                                         while microbiotic crust cover and diver-                                   pe
                                                                                                                         sity decrease.                                                             ext
                                                                                                                             Valley-bottoms are the hottest and                                     clim
                                                                                                                         driest areas, and are commonly domi-
                                                                                                                         nated by dryland shrubs with widely                                        ing
                                                                                                                         spaced bunchgrasses such as blue-                                          sta
                                                                                                                         bunch wheatgrass and needle-and-                                           tio
                                                                                                                         thread grass, scattered forbs such as                                      are
                                                                                                                         prickly pear cactus, and a diverse                                         10
                                                                                                                         microbiotic crust. These grasslands are                                    ha
                                                                                                                         the most sensitive to disturbance, and                                     fir
                                                                                                                         have been the most affected to date by                                     fue
                                                                                                                         livestock, invasive plants, and develop-                                   en
                                                                                                                         ment.Middle slopes of valleys are usu-                                     lin
                                                                                                                         ally dominated by bunchgrasses with a                                      the
                                                                                                                         wider diversity of forbs; scattered areas                                  in 
                                                                                                                         of shrub-steppe also occur.                                                an
                                                                                                                             At the upper edges of valleys and                                      thi
                                                                                                                         on adjacent plateaus, slightly cooler                                      tim
                                                                                                                         and moister climates result in condi-                                      D
                                                                                                                         tions favourable for both forests and                                      ex
                                                                                                                         grasslands. Here, frequent low-inten-                                      to 
                                                                                                                         sity fires likely played a key role in                                     lan
                                                                                                                         maintaining grasslands in a mosaic                                         ele
                                                                                                                         with open forests. With fire exclusion,                                    mo
                                                                                                                         many of these grassland areas have
                 plant species is paralleled by a diver-                 Southern interior grasslands include            been invaded by trees and are shrink-                                      tle
                 sity of mammals, birds, amphibians,                 ecosystems dominated by bunchgrasses,               ing rapidly. When undisturbed, these                                       ye
                 reptiles, and insects that are adapted              and ecosystems dominated by dryland                 grasslands are dominated by rough or                                       lan
                 to and depend on grassland eco-                     A careful              shrubs such as sage-         Idaho fescue in southern valleys, and                                      ste
                 systems for food, shelter, and                                             brush or antelope-           by porcupine grass in the Cariboo-                                         of
                 breeding sites.                                     look reveals           brush with grasses           Chilcotin. They have a wide diversity                                      th
                     Underneath the more obvious                     a tiny                 and forbs. These             of forbs, although their microbiotic                                       tio
                 plants of undisturbed grasslands                                           shrub-dominated              crusts are often less diverse and less                                     int
                 lies a fragile, easily disturbed crust of           world of               ecosystems are some-         continuous because thicker litter lay-
                 lichens, mosses, and algae known                    lichens and            times referred to as         ers limit their development.                                               W
                 as a microbiotic crust. A careful                                          shrub-steppe. Both                                                                                      co
                 hands-and-knees look reveals a                      miniature              livestock grazing and        What is their history?
                 tiny world of lichens and minia-                    mosses.                fire exclusion have             n British Columbia, southern interior
                 ture mosses, many of which reveal                                          likely resulted in the          grasslands are ancient communities
                 their brightest colours only after a rain-          conversion of some bunchgrass-                         that probably became established from                                   G
                 fall. This crust binds the soil together in         dominated areas to shrub-steppe.                    Ithe south about 10 000 years ago as the                                   geo
                 an irregular surface that enables soils to              Grasslands exhibit distinct ecologi-            Pleistocene glaciers were melting. Dur-                                    ern
                 better capture moisture, prevents wind              cal trends associated with moisture                 ing a warm climatic period from about                                      sm
                 and water erosion, and provides some                and temperature gradients, which                    9000 to 4700 years ago, species from the                                   are
                 nitrogen to grassland plants.                       are in turn related to elevation changes            arid Great Basin west of the Rockies                                       hig
               moved northward into the hot, dry                                                       Why are they important?
               valley bottoms of southern British         Range of southern interior grasslands.          rasslands have a wide range of
               Columbia.Grasslands covered a much                                                         important values, one of which is
               greater area during this warm climatic                                                     their intrinsic value – they are an
               period, but shrunk to their current                                                     Gessential part of British Columbia’s
               extent about 4000 years ago when the                                                    and North America’s unique biodiver-
               climate became moister and cooler.                                                      sity and natural heritage. Grasslands
                  Fire was historically a strong shap-                                                 are naturally rare and have been sub-
               ing influence in grasslands. Fires,                                                     stantially reduced by human activities.
               started both by lightning and tradi-                                                    All of us are reliant on the ecosystem
               tional burning by aboriginal peoples,                                                   services that grasslands provide,
               are estimated to have occurred every                                                    including the safe capture, storage, fil-
               10 to 20 years. Most grassland plants                                                   tration, and release of water and clean
               have structures that are able to survive   of grasslands are privately owned, 10       air. Grasslands provide places for recre-
               fires moving through the fine grass        percent are within Indian Reserves,         ation, education, eco-tourism, ranch-
               fuels and thrive on the flush of nutri-    and less than half are on Crown land.       ing, and hunting. Healthy grasslands
               ents released by burning. Tree seed-       Of publicly owned grasslands, about         with dense grass are more resistant to
               lings were able to establish only where    90 percent are under grazing tenures.       invasion of non-native plants and pro-
               there was more moisture or             Fire was           Just over three-quarters     vide more forage and wildlife habitat
               in an unusually moist year,                               of private land grass-       than degraded grasslands. Grasslands
               and most did not acquire               historically  lands lie within the Agri-        are important to aboriginal peoples,for
               thick, fire-resistant bark in          a strong           cultural Land Reserve.       harvest of bitterroot, balsamroot, and
               time to survive the next fire.                               Only a small percent-     other plants found in grasslands.Grass-
               During the past 140 years,fire         shaping            age of our grasslands are    lands provide a scenic backdrop for
               exclusion has allowed trees            influence in protected – Eight per-             many communities and are places to
               to invade and shrink grass-                               cent lie within Crown        enjoy nature and observe wildlife.
               lands, especially at higher            grasslands.        protected areas, and         The warm climate and aesthetic values
               elevations and on cooler,                                 non-government con-          of grasslands have contributed to
               moister sites.                             servation organizations have pur-           increased real estate values in many 
                  Grasslands have been grazed by cat-     chased less than one percent of pri-        valleys – ironically this has increased 
               tle, horses, and sheep for the last 140    vately held grasslands for protection.      the threats to the beauty and bio-
               years. Human populations in grass-         Larger grassland protected areas            diversity that has attracted people to
               land-dominated valleys have increased      include Lac du Bois Grasslands Pro-         live there.
               steadily since the mid 1800s. Both         tected Area near Kamloops, South               Many of the values of grassland
               of these factors have played a role in     Okanagan Grasslands Protected Area          landscapes lie in the diversity of eco-
               the present condition and distribu-        west of Oliver and Osoyoos,and Churn        systems that occur there, including
               tion of British Columbia’s southern        Creek Protected Area west of the            woodlands, old forests, wetlands,
               interior grasslands.                       Fraser River from Clinton.                  riparian areas, aspen copses, cliffs,
                                                              Nearly all grassland and shrub-         rock and talus. Most of these ecosys-
               What is their                              steppe natural plant communities are        tems are also considered threatened
               conservation status?                       considered at risk. Presently, 15 of        or endangered, and together this
                  rasslands in the southern interior      these plant communities have been           diverse mosaic of ecosystems within
                  occupy less than one percent  blue-listed (special concern) or red-                 the grassland environment provides
                  (662 872 ha) of British Columbia’s      listed (endangered); evaluations for        habitat for a wide diversity of plants,
               Gland area. Because grasslands are         other grassland plant communities           mammals, birds, reptiles, amphib-
               geographically restricted to hot south-    are pending. Many other plant com-          ians, and invertebrates.
               ern interior valleys and occupy a very     munities associated with grassland             Although grasslands cover a very
               small portion of British Columbia’s land   landscapes, such as wetlands, aspen         small portion of British Columbia’s
               area, these ecosystems are considered      copses, and woodlands, are also             land area, they provide habitat for
               highly endangered.More than 40 percent     endangered.                                 more than one-third of the province’s
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...Ms h ecosyste in britis columbia t riskt risk aa grasslands of the southern interior cover less than one percent british s land area ministry sustainable resource management water and air protection plants can go unnoticed reversing cheatgrass may result too fre such changes be difficult people quent intense fires some often recreate without valley bottom realizing that fragile easily dis why are turbed crust lichens mosses what they at algae known as a microbiotic rasslands n hot dry regions soils damaged by semi arid ecosystems dominated lie grass both motorized vehicles mountain bunchgrasses shrubs non lands bikes single track become an forbs g iwildflowers dryland erosion site weed infested occur hottest driest valleys were naturally limited invite further traffic expansion including okanagan thompson extent when european settlement began urban suburban populations also nicola fraser chilcotin kettle mid significant areas brings more pets recreation which kootenay represent norther...

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