Large carnivore population review for the Kootenay Region

Transcription

1 Large carnivore population review for the Kootenay Region Garth Mowat Senior Wildlife Biologist BC Ministry of Environment, Kootenay Region Suite 41, 333 Victoria St., Nelson British Columbia, V1L 4K3, Canada Ph. (25) FAX (25) September 25, 27 The objective of this review was to collate existing data for large carnivores in the Kootenay Region of BC including long-term management data such as kill levels and hunter success. The focus was to document changes in population size in the past 3 decades and where possible review density. The review is meant to provide wildlife and habitat managers with an up to date summary of population status and also to demonstrate to other interested readers the current level of population knowledge for this suite of species. The Kootenay Region The landscape of the Kootenays has changed dramatically over the last century. The human population grew quickly during the late 18 s and early 19 s but has only increased from 16, to 125, between 1986 and 25. Large scale loss of forest is commonly reported around the later 18 s to the early 19 s due to both fires and land clearing for settlement and agriculture (The state of British Columbia s Forests ). Re-growth of these forests was a longer term event but probably had no less impact than the aforestation event. The amount of land in early seral forest (1-8 years) has decreased in interior BC since 1957 while the amount of forest >8 years old has increased. This increase in the amount of mid-seral forest increased in concert with large scale commercial forestry and can be attributed to the aging of forest that burned or was cut before 1957 and, the onset of professional firefighting which has reduced the recruitment of early forest. Presumably, the amount of very old forest decreased during this period. The amount of non-forested land such as grasslands, meadows, and early seral burns is likely much less than historically (Braumandl et a. 1994). The number of roads probably increased slowly before the second world war while road density increased rapidly after the war (see McLellan 199 for an example from the Flathead Valley in the southeast corner of the region). Presumably livestock densities increased through this period as well. Annual variation in weather probably affects energy balance for bears due to their reliance on plant matter in spring and mast and fruit in summer and fall which may have important consequences on survival. Mattson et al. (1992) show that human-caused grizzly bear mortality is much higher during years of low white-bark pine seed production (Fellicetti et al. 23). Presumably, there is a similar effect during years of berry crop failures. Precipitation has increased over the past century in the central Kootenays, however snow appears to declining while rain increases. 1

2 Wildlife use and management prior to the 197 s greatly influenced wildlife populations. Caribou populations had declined markedly since the previous century (Russell 1974, Spalding 2). In contrast, moose, elk, and white-tailed deer increased in distribution and abundance through the last century (Demarchi et al. 1992, Shackleton 23). Predators were persecuted heavily during the first half of the last century. By about 196 many large and small predators were at low abundance and only changes in both management and public attitudes allowed recovery. Methods I summarized all available population data for carnivores in the Kootenay Region that had not been previously analyzed. Hunter kill statistics are collected through hunter questionnaires in BC which are distributed annually via mail following the close of the hunting season and through compulsory inspection and reporting. Questionnaire return rate is about 7% (John Thornton, personal communication). Hunters are asked for information on the number of animals they killed and the time they spent hunting each species. Hunter success and effort per kill (often termed catch per unit effort or CPUE) were calculated from summaries of the hunter questionnaire data by area of interest. Reporting of wolf kill by trappers has been required since at least the 198 s and since 1975, cougar and grizzly bears killed by hunters have been inspected and marked by a representative of the provincial government. This compulsory reporting ensures all legally killed animals are recorded and ancillary data are collected on location, size, age, and sex. Most cougar and grizzly bears killed for control reasons or killed illegally and recovered are also recorded in this database. Hence the compulsory inspection database is a comprehensive database regarding mortality of the species. Median age is presented as an index of population change because it has been shown to better correlate to population decline than mean age in bears (Harris and Metzgar 1984). Linear or polynomial regression lines are fit to many of the time series data to show trend. These are not a thorough analysis of trend because usually lines were fit to yearly means, not raw data, and annual sample size often varied markedly. I summarized growing season rainfall in order to compare this with trends in bear populations and mortality. Results and Discussion Cougar Hunter harvest is managed by sub-region wide quotas on the female kill which have been adjusted from time to time. Annual bag limits were one cougar in the East Kootenay and two in the West Kootenay. Until 26, the hunting season ran from September to the end of February in the East and to the end of March in the West; few cougar were killed before November and most are killed by hunters using trailing dogs. In the bag limit was set to one and the season ending date to the end of February for the entire Kootenays. In addition sub-regional quotas were set for three parts of the Region and were slightly reduced 2

3 for some areas. Hunter may pursue cougars with dogs after the annual quota is reached (until Feb. 28) as long as they do not carry a gun and have a valid hunting license. About 4 cougars were killed per year by hunters between 1976 and 1992 in the Kootenay Region. Most cougar are killed in the south half of the Region and the greatest number are killed in Management Unit 4-3 (Fig. C1). During the 199 s this number rose to a peak of 167 and has since declined to just higher than pre-1993 levels (Fig. C2). The number of cougar killed during problem interactions with people may provide a rough index of cougar population size and these numbers roughly mirror the hunter kill data (Fig. C2). Hunter success was highest in 1997 but has since declined to levels similar to pre1993 (Fig. C3). Resident hunter effort/kill has increased since 1997 (Fig. C4) where hunter effort per kill was calculated by dividing the total kill by the total time hunters spent in the field. Effort changed little through 2, except for 1997 when effort per kill was very low, but appears to have increased since then. Hunter success and effort/kill for non-resident hunters was variable (Fig. C3 and C4) which was likely due to the low sample size until the mid 199 s; success for non-residents has not changed since The age of hunter killed cougars has declined since 199 (Fig. C5-C6). The size of male hunter killed cougars has also decreased since 199 (Fig. C5). Resident and non-residents kill cougars of similar age (F r = 4.2 years, n = 278, SD = 2.56; F nr = = 4.2 years, n = 69, SD = 2.45; M r = 3.7 years, n = 257, SD = 2.69; M nr = 3.7 years, n = 91, SD = 2.71). 3

4 Fig. C1. Cougar hunting kill locations in the Kootenay Region between

5 Total hunter kills Female hunter kills Male hunter kills Problem kills Fig. C2. The number of cougar killed in the Kootenay Region, based on compulsory reporting resident hunters non-resident hunters Hunter sucess (%) Fig. C3. Hunter success for cougar in the Kootenay Region of southeast BC,

6 8 7 resident hunters non-resident hunters 6 Hunter days/kill Fig. C4. Hunter effort per kill for cougar in the Kootenay Region of southeast BC, skull length R 2 =

7 Fig. C5. The average male skull length of hunter-killed cougars in the Kootenay Region between The trend line depicts a linear regression and fit is shown by the R 2 value. Sample size varied from 4-22 among years A. East Kootenay B. West Kootenay 7 7 Age in years R 2 =.68 Age in years R 2 = Fig. C6. The median (dark bar) and mean (gray square) age of male hunter killed cougars in the Kootenay Region Error bars are a one standard deviation. Lines depict linear regressions on medians and fit is shown by the R-squared value. The West Kootenay included Management Units 4-3 to 4-6 and 4-2 because they were hypothesized to have higher kill rates than other areas in the East Kootenay. The median age of male cougar killed was similar in the east and west Kootenays even though hunting regulations were more liberal in the West Kootenays (Fig.C6). Finer scale examination of the heavily harvested Management Units such as 4-3 all showed similar trends in male age. Kill data suggest that cougar numbers were comparatively low in the 198 s, increased through the 199 s and have since decreased again. Success and effort from resident hunters would suggest numbers have declined since about 2 and this trend may be ongoing. The number of females killed has declined since 23 which could indicate hunters are more carefully targeting male cougar. Alternatively, this data supports the possibility that hunting kill has been unsustainable which has reduced the number of female cougar in the Region. The current level of male harvest could in part be supported by immigration of sub-adults from surrounding jurisdictions or Regions because sub-adult males commonly disperse while females rarely do (Hornocker et al. 197). This alternative is supported by the decreasing age and size of hunter killed males which is expected if a greater proportion of the kill are immigrants. Low cougar numbers in the 197s may be due to previous predator control efforts and the lack of management controls during the 196 s to 198 s. The end of predator control and more restrictive management should have allowed cougar populations to increase during the 198 s but numbers appeared static until the early 199 s. Deer and elk numbers were high during this period (Wilson and Morley 25). The possible decline in cougar numbers followed a major decline in deer and elk numbers in the 199 s. Ungulate numbers have since recovered to near pre1995 levels but there is no evidence for a recovery in cougar numbers. Current levels of harvest are probably holding cougar populations at levels below 7

8 carrying capacity alternatively, like in the 198 s there may be a substantial time lag (i.e. 1 years) between prey increase and cougar numerical response. Is the current population trend for cougars declining, stable, or increasing? This question cannot be answered from harvest data alone for many reasons including regulation changes which confound data analysis, and, cougar hunters do not necessarily want to kill a cougar every year so the number of cougars killed is influenced by the number of people recruited into the sport. Hunting dogs are expensive and so the number of new recruits is probably influenced by economic factors. The stable hunter success and effort for non-resident hunters since 1997, who presumably all would like to kill a cougar, suggests cougar numbers are currently stable in the Kootenay Region. Numbers killed, and success rate and CPUE data for resident hunters suggest a declining population which is supported by on-going decreases in age of hunter killed males. However, decreasing age also occurs in an increasing population and seasoned resident hunters many be less motivated to kill cougar because they already have trophies from previous years which supports the hypothesis that cougar numbers are currently stable. Research in the southwest corner of the Region documented a population decline between and more stable growth to 23 (Lambert et al. 26) which supports the non-resident data above. The main cause for the decline was high adult mortality from hunting. Clarke (23) suggested that immigration from Washington was rescuing this study population in the South Selkirk Mountains south of Nelson. Age ratio data from an unhunted area of the East Kootenay suggested an increasing population during (Spreadbury et al. 1996). This study shows that at least some cougar populations likely began increasing before that suggested by the mortality data (Figs. C4-C5). Available data are somewhat contradictory but cougar populations in the Kootenays are probably stable or declining slowly and, harvest is at least partly maintained by immigration from surrounding areas. The liberal cougar hunting regulations and lower number of cougar being killed currently, compared to the 199 s, suggests that cougar numbers are below carrying capacity and this level is presumably being maintained by hunting. Spreadbury et al. (1996) presented cougar densities in an unhunted portion of the Fording River area of the East Kootenay of cougars/1 km 2 during winters This density is over double that documented by Lambert et al (26) in the Pend d Oreille Valley in the WK. Ungulate biomass was likely much lower in the West Kootenay study area. Cougars in mountainous areas such as the Kootenays have different ranges among seasons (Clarke 23) making it difficult to extrapolate densities because some areas of the landscape will likely be devoid of cougars at different times of the year. Late summer or fall densities would likely be most useful for extrapolation because cougar are most widespread during this season but, there are not enough measures of cougar density to predict population size for the Region. Wolves Current wolf management includes a 9 month hunting season and no closed season in the East Kootenay Trench and an annual bag limit of two animals per hunter. The trapping season is 5.5 months long with no bag limit. The trapping and hunting season are unlikely to 8

9 have limited kill levels over the past 3 years however reporting has changed during that time and may have had a larger influence on data. The number of wolves killed was low during the 198 s. The kill increased during the 199 s, peaked in 1996, and declined until 1999 (Fig. W1). The kill increased to a second peak in 22 and has again declined until 24. Forty-three percent of the wolves killed since 199 were females. Recent survey work in the West Kootenay suggests there are >34 wolves in the Columbia Trench north of Revelstoke (Gaynor et al. 27). There are at least 3 resident wolves in the Central Selkirk Mountains between Slocan and Trout Lakes while wolves are patchy and probably do not number much more than 13 in the South Selkirk Mountains. Wolf numbers have likely increased over the recent past (Gaynor et al. 27). No other population data exist for wolves in the Kootenay Region HUNTER KILL TRAPPING KILL TOTAL WOLF KILL Fig. W1. The recorded number of wolves killed in the Kootenay Region of BC, Each year ends on March 31. Wolf numbers were low throughout British Columbia in the 196 s due to bounty hunting and organized predator control (Tompa 1983). Tompa (1983) reports that wolves were close to extinction in southeast BC by Similar reductions occurred in Alberta (Gunson 1992). Management changes through the early 197 s allowed wolves to recover throughout BC and Alberta and the harvest data for the Kootenay Region grossly document this recovery. Wolf numbers appear to have recovered first in areas with higher moose numbers. Wolves are still rare in much of the West Kootenay, especially the southern portion. The lack of recovery in the West Kootenay may be due to excessive snow depths or the relative lack of moose. The recent increase in moose numbers north or Revelstoke and the consequent increase in wolf sightings in that area would suggest that prey levels influence recovery more than snow depth. Moose numbers are increasing in the southern part of the West Kootenay (Robinson 27) and wolves appear to following (Gaynor et al. 27). The recovery in wolf numbers is broad in scale. Numbers have recovered in Montana, Idaho and Wyoming from near extirpation up to the late 198 s to greater than 1 animals today (Sime et al. 26). The recovery in Wyoming was aided by a transplant into Yellowstone 9

10 National Park but packs became established in northern Montana in the early 198 s from the Flathead area of BC. (B. McLellan personal communication) and recently in Idaho. These animals presumably immigrated from southern BC and Alberta (Sime et al. 26, T. Laysar, pers. comm.). Black bears The black bear hunting season is liberal with a spring and fall season totaling nearly 6 months and an annual bag limit of two. Juvenile bears and their accompanying parents are protected from hunting; no bear in a family group may be legally hunted. In 1993 regulations necessitated hunters to use the meat of killed black bears while previously it was necessary to use either the hide or the meat; this change in utilization standard may have reduced hunter effort. The number of black bears killed by hunters in the Kootenays has declined since the 198s to present (Fig. B1), but this reduction is modest and the certainty of the decline is somewhat masked by the yearly variation in kills. The cause may be population decline but could also be related to declining hunter interest. It must also be noted that these data are based on hunter questionnaire, not compulsory inspection, and hence are likely more variable than grizzly bear or cougar kill data. The number of black bears killed for control reasons was highly variable during the 1 years for which data were available (Fig. B2). Control kills are usually less than half the number of hunter killed bears but recorded control kills have nearly equaled hunter harvest in some years (e.g. 1998). Transplanting black bears was phased out during the 199 s. More recent data are not summarized by wildlife management regions but the data confirm continued variation in problem kills. This variability is likely related to food availability within years, which appears strongly influenced by yearly weather patterns. The influence of population size on the problem kill data could be masked by annual weather. Hunter success data and hunter effort per kill suggest a decline in population size through the 198s and little change following that period to the present (Fig. B3). Alternatively the decline in hunter success may be due to the increase in the average age of the forest in the Kootenays which would make hunting more difficult. Forest succession and the increase in grizzly bear numbers may also explain the suggested decline in black bear numbers. There may have been modest declines in black bear numbers in the last three decades but a major decline in numbers is unlikely. More certain conclusions are not possible with current data. 1

11 R 2 = Fig. B1. The number of black bears killed by hunters in the Kootenay Region, KILLED RELOCATED Fig. B2. The number of problem black bears killed in the Kootenay Region,

12 45 4 CPUE Hunter success 1 9 Hunter days/kill Fig. B3. Hunter success (the proportion of hunters that killed a bear) and catch per effort (days per kill) by resident hunters for black bears in the Kootenay Region, Population size has been estimated for only one area in the Kootenays (Reynolds 22, Boulanger 23). The study was in the upper Columbia River area nearly centered on the town of Golden. The population estimate for this 496 km 2 area was 342 (CI ) which generated a density of 83 (CI 71-13) bears per 1 km 2. Using a tighter grid in 1997 with fewer captures near the edge of the grid and thus greater chance of violating geographic closure, Boulanger (23) estimated 42 bears/1 km 2 (SE=.19, CI=4-48). Both are relatively low densities for black bears but this area contained considerable rock, ice, human settlement and grizzly bears, which were not accounted for when deriving density. Miller et al. (1997) and Mowat et al. (25) both concluded that black bears occur at higher densities in low elevation densely forested areas compared to more rugged mountainous areas, likely because competition with grizzly bears is greater in upper elevation areas where there are few trees to provide refuge from grizzly bear aggression (Apps et al. 26). A summary of published data also suggested that black bear density was higher in areas with higher rainfall (Mowat et al. 25). These observations likely apply in the Kootenay Region as well. Predicting population size for black bears in the Kootenay Region would be very uncertain given the paucity of data on density in habitats similar to the Kootenays. There are, however, numerous hair samples of bears incidentally captured during grizzly bear population censuses that could be used to estimate black bear numbers as was done with the Upper Columbia River data Hunter success (%) Grizzly bears Population size is managed by grizzly bear population units (GBPUs) in British Columbia (Fig. G1). Hunting is managed by quota which is calculated by GBPU. There are 16 GBPUs in the Kootenay Region and 4 units have been closed to hunting for several years. Grizzly bear hunting has been regulated by Limited Entry Hunting since 1976 when compulsory inspection of all bears that are killed began. All bears over 1 year of age that are killed in a 12

13 unit are counted against the allowable harvest, including problem kills. A hunter can lawfully kill one grizzly bear per year in BC. Hunting season runs from April 1 to June 5 and there is no fall hunting season for grizzly bears in the Kootenay Region. Hunters are requested to shoot male bears although gender can be difficult to ascertain in the field. It is illegal to shoot a bear in a family unit and this regulation protects both juvenile and yearling cubs and their female parent. Even with Limited Entry Hunting the hunter kill of grizzly bears has varied considerably since 1976 (Fig. G3). The long-term average number killed per year was 55 while the average kill after 21 (a single year when there was no hunting of grizzly bears) was 47, suggesting a slight decrease in kill recently. It is interesting to note that the hunter kill in 1996 was almost double the long-term average even though the harvest was managed by Limited Entry. In the East Kootenay, grizzly bears tend to be killed by hunters throughout the population units while, in the north and west portion of the region bears kill locations are often grouped into a few spots in each unit (Fig. G1). Kill locations are probably grouped in the higher snow areas of the region because many areas are still snow covered during the hunting season leaving few locations available for hunting. Few hunter or control kills occurred in Provincial Parks likely because most parks are unroaded areas at high elevations where hunters are not likely to hunt grizzly bears. The number of grizzly bears killed for control reasons (either by a Conservation Officer or citizen who felt the bear was a threat to life or property) averaged 12.6 between 199 and 25 (Fig. G4). Problem kills averaged 19% of the grizzly bears known to have been killed each year. Control kills occur most often near human centers except for the South Rockies and Flathead units where control kills are more numerous than other parts of the Region and are found throughout both units (Fig. G2). Most control kills that are not close to human population centers are by citizens during the autumn hunting season. There was no apparent relationship between summer rainfall and the number of grizzly bears killed for control reasons. However, the number of bears killed for control reasons is also influenced by the closure of dumps and other large food sources which may obscure relationships to natural food resources. The single largest number of problem bears killed was in 1995, the year following the closure of the Revelstoke dump (Proctor and Neumier 1996), other dumps were also closed during the 199 s which likely contributed to a larger number of problem bears killed than previously. 13

14 Fig. G1. The location of grizzly bear hunter kills in the Kootenay Region

15 Fig. G2. The location of grizzly bear control kills in the Kootenay Region

16 1 9 8 All hunter kills Non-resident hunters Resident hunters Number bears killed Fig. G3. The number of grizzly bears killed by hunters in the Kootenay Region of British Columbia, Females Males Total Fig. G4. The number of grizzly bears killed for control reasons in Region

17 Since 1976 females have composed 33% of the kill. Resident hunters tend to kill more females (35%) compared to non-resident hunters (27%). The proportion of females in the kill varies among years and both resident and non-resident hunters regularly kill greater than 3% females, which is the current maximum in the provincial harvest policy (Fig. G5). It is much less likely that female kill will exceed 3% in any GBPU when averaged over the newly adopted allocation period of 5 years. Hunter success has increased since 198 suggesting that either grizzly bear numbers have increased or hunters have become more efficient, perhaps due to improved access (Fig. G6-G7). The average age of grizzly bears killed by hunters was 7.9 (n = 743, SD = 4.95) years with little difference between sexes (males = 7.7, females = 8.3). Non resident hunters kill bears that are about a year older than resident hunters (F r = 8. years, n = 168, SD = 5.14; F nr = = 9. years, n = 71, SD = 5.39; M r = 7.4 years, n = 359, SD = 4.65; M nr = 8.6 years, n = 143, SD = 5.12). Bears killed for control reasons average 5.6 years (n = 6, SD = 5.53), more than two years younger than hunter killed bears. 6 5 Percent females in kill Non-resident hunters Resident hunters Fig. G5. The female proportion of the grizzly bear kill in the Kootenay Region. The line at 3 shows the female proportion of the harvest that is the maximum target in the current grizzly bear harvest policy. 17

18 8 7 Resident hunters Non-resident hunters Percent successful hunters R 2 =.44 R 2 = Fig. G6. Hunter success by resident and non-resident hunters for grizzly bears in the Kootenay Region, Lines are second-order polynomials fitted to these points Resident hunters Non-resident hunters 6 Hunter days per kill R 2 =.26 1 R 2 = Fig. G7. Catch per effort (days per kill) by resident and non-resident hunters for grizzly bears in the Kootenay Region, Lines are second-order polynomials fitted to these points

19 A closer look at the harvest and age data may suggest where grizzly bears might be increasing or decreasing in number. Data are too few to analyze by GBPU in most cases except for the presentation of simple means across time (Table G1). I grouped MU's based on human density assuming that human density would be related to historical declines in abundance and current harvest pressure. The area north of Highway 1 (MU's 4-36 to 4-4), the area south of Hwy 1 (MU's 4-27 to 4-34), and the southern Rocky Mountains (MU's 4-1, 4-2, 4-21 to 4-25, & 4-35) I considered secure grizzly bear populations. The southern portion of the Central Selkirk mountains (MU's 4-15 to 4-18) and the South Purcell mountains (MU's 4-5, 4-6, 4-19, 4-2, & 4-26) I considered insecure populations. The Monashee (MU 4-32) and Spillimacheen (MU 4-34) units may also be less secure populations because they border insecure populations. Hunter success (Fig. G8-G9) and the age of males bears killed by hunters (Fig. G11) has increased in the northern portion of the Region and all of the Rocky Mountains while the proportion of males in the kill has does not appear to have changed (Fig. G1). These data suggest an increase in grizzly bear population size since about 199. In contrast, hunter success does not appear to have increased in the southern Purcells (Fig. G9) and it may have declined for guided hunters (Table G1). Nor has hunter success increased in the south Central Selkirk Ranges (Fig. G8). The proportion of males in the kill has increased in these units since 1976 while the median age of males in the kill has not increased measurably (Fig. G1). The mean age of male bears killed in secure areas of the Kootenay Region between 1976 to 25 was 8.4 year (n = 378, SD = 4.93, Med = 7) while that in the south central Selkirks and Purcells was 6.6 years (n = 79, SD = 3.57, Med = 6). These data do not support an increase in population size in the south central Selkirks or Southern Purcell mountains. The south Central Selkirk and Southern Purcell management units are probably the least secure hunted populations in the Kootenay Region. The Monashee (4-32) and Spillamacheen (4-34) units border the insecure areas described above and I examined data for these areas for signs of population change. In the Monashee unit resident hunter success may have increased while non-resident success is similar to other secure units (Table G2). Hunter success was lower in the Spillamacheen unit than in other secure areas to the north and west and more similar to the southern Rocky Mountains (Table G2). I combined data from the south Central Selkirk and Purcell units in the age and sex ratio analyses and the increase in the male proportion of the kill appeared less when these two units were grouped with the other secure units (Fig. G1). Similarly, the age of hunted male bears appears to increase when these two units were included with the other insecure units (Fig. G11). These data suggest that grizzly bear populations have increased in the Monashee and Spillamacheen units, similar to other units in the region. Hunter success for residents was low in the both the Granby and South Selkirk units before they were closed to hunting (Table G2). 19

20 Table G1. Grizzly bear hunter success for 5 areas of the Kootenay Region. The areas in shaded grey and italic font are considered less secure populations than the others (see text). Area Date Resident hunter success (%) North of Hwy 1 North of Hwy 1 South of Hwy 1 South of Hwy 1 southern Central Selkirks southern Central Selkirks South Purcells South Purcells South Rockies South Rockies Resident hunter days/kill Nonresident hunter success (%) Non-resident hunter days/kill

21 Table G2. Grizzly bear hunter success for 4 Grizzly Bear Population Units in the Kootenay Region. GBPU Date Resident hunter success (%) Spillamacheen (MU 4-34) Spillamacheen (MU 4-34) Monashees (MU 4-32) Monashees (MU 4-32) Granby-Kettle MU s 4-9 & 4-14) South Selkirks MU s 4-7 & 4-8) Resident hunter days/kill Nonresident hunter success (%) Non-resident hunter days/kill

22 Fig. G8. Grizzly bear hunter success for three large areas in the West Kootenay: the area north of Highway 1 (MU's 4-36 to 4-4), the area south of Hwy 1 labeled Northern Monashees, Selkirks & Purcells (MU's 4-27 to 4-34), and the southern portion of the Central Selkirk Mountains (MU's 4-15 to 4-18). Hunter success has increased in the northern two areas but not in the southern portion of the Central Selkirk Mountains. Figure G9. Grizzly bear hunter success for two large areas in the East Kootenay: the South Purcell Mountains (MU's 4-5, 4-6, 4-19, 4-2, & 4-26), and the Southern Rocky Mountains (MU's 4-1, 4-2, 4-21 to 4-25, & 4-35). Success has increased in the southern Rockies but does not appear to have increased in the South Purcells. 22

23 Fig G1. The proportion of males in the combined resident and non-resident hunter kill in all MU's that are considered secure, those that may considered insecure (4-5, 4-6, 4-15 to 4-2, 4-26, 4-32 and 4-34) and those that are the least secure (the above units minus 4-32 and 4-34). The proportion of males in the harvest has not changed in secure grizzly bear populations but it may have increased recently in insecure populations. 23

24 18 A. Secure areas Median age in years R 2 = B. Insecure areas Median age in years R 2 = C. Most insecure areas Median age in years R 2 = Fig. G11. Median ages for male grizzly bears in: A) all MU's that are considered secure, B) those that may considered insecure (4-5, 4-6, 4-15 to 4-2, 4-26, 4-32 and 4-34) and C) those that are the least secure (the above units minus 4-32 and 4-34). Secure units are all 24

25 hunted units except those mentioned above. Trend lines were fit using linear regression. Error bars are one standard deviation. Hunter success data suggest that there has been an increase in the grizzly bear population in the Kootenay Region since the late 197's, which is supported by a single empirical study in the southeast corner of the Region. McLellan and Hovey (1996) documented an increasing grizzly bear population in the Flathead area in the southeast portion of the Region between 1979 and Subsequent data suggests population growth has stabilized (B. McLellan, personal communication). The increase in average age of males bears would suggest a reduction in kill rate, which allowed the population to get older. However, the increase in age may also be explained by the fact non-resident hunters have killed a greater proportion of the bears over time (Fig. G12), given that non-resident hunters tend to kill older bears than resident hunters. However, the population south of Hwy. 1 was largely hunted by resident hunters and hunter success increased in this (Fig. G8), as in other areas where the grizzly population appears secure. Anecdotal evidence suggests an increase in bear numbers in many parts of the Region over the last 2-3 decades. Proportion bears killed by non-resident hunters (%) R 2 = Fig. G12. The proportion of grizzly bears killed by non-resident hunters in the Kootenay Region, The South Selkirk and Yahk units are continuous with populations in the United States where the species is considered endangered. Three units (Kettle-Granby, South Selkirks, and Yahk) are closed because the resident population is thought to be less than 1 or, well below carrying capacity. This has been demonstrated in the Kettle-Granby unit. The population estimate in 1997 from a DNA-based inventory in part of the unit was 38 (CI 26-84; 25

26 Boulanger et al. 22). Although, grizzly bears do occur outside this study area in this unit, anecdotal evidence would suggest they are few (Gyug 1997). This summary is over 1 years old and there is some anecdotal evidence suggesting grizzly bears are expanding their range to the south in this unit. Radio-telemetry based work suggested a population size below 1 for the South Selkirk Mountains, including the US portion, during the 198 s (Weilgus et al. 1994) and subsequent analyses have suggested an approximately stable population since that time (Wakkinen and Kasworm 24). Recent inventory results and extrapolation to the entire Canadian portion of this unit estimate population size at 58 (95% CI = 5-7). Population genetic analyses of this and surrounding populations demonstrated demographic isolation of the South Selkirk population (Proctor et al. 25) over a very approximate period of 6 years (M. Proctor, personal communication). Radiotelemetry work principally in the United States suggested a declining population in the Yahk GBPU (Wakkinen and Kasworm 24). While the Canadian portion of this population may not be declining, a recent population estimate for this unit is only 2 bears in the Yahk unit in Canada with no more than double that number in the United States. There has been no hunting in these closed units for 1 or more years but control kills are more common in these units than in many units to the north (Table G3, Fig. G2), probably because the human population is greater in the southern units. The Yahk unit is at the greatest conservation risk of any GBPU in the Kootenay Region. Hunting quotas in the South Purcell unit were set at half the level of the rest of the Kootenay Region in order to promote movement and recovery into the Yahk unit. Grizzly bear densities currently decrease from north to south in the Purcell Mountains (Proctor et al. 27) and the Yahk unit has lowest grizzly bear density in the Kootenay Region (Mowat et al. 25). Similarly, grizzly bear numbers were low in the Valhalla Unit, south of Valhalla Park (Mowat and Strobeck 1998, Mowat et al. 25) which precipitated the closure of this unit in 21. Bear densities would appear normal in Valhalla Park and to the North (Mowat and Strobeck 1998). These authors also detected few bears south of Kokanee Glacier Park in the Central Selkirk unit. Density was judged to be below carrying capacity in the Monashee unit in the late 199's and the unit was closed to hunting. There is no information on grizzly bears numbers from this unit. Hunting has since resumed on the Kootenay side but not on the Okanagan side of the unit. 26

27 Table G3. Hunting closures and total recorded human caused mortality for grizzly bears in five threatened grizzly bear populations in the Kootenay Region. GBPU Year closed Known mortality Known mortality Approximate population size Granby-Kettle 198 s on South Selkirks 1991, 1995 on Yahk 1976 on Valhalla 21 on Monashee The portion of this unit in the Okanagan Region remains closed to hunting. 2 This includes mortality in the Kootenay Region only. Several early studies of grizzly bear population density were done in the Kootenays before the mid199's and, after this period a number of genetic-based inventories were done. Density varies from 25-5 bears/1 km 2 and density was lower in the south part of the Region, presumably due to the greater human density (Mattson and Merrill 22, Mowat et al. 25). Dryer areas, such as the Rocky Mountain east slopes, or areas with little relief, such as the boreal forest, support lower bear densities (Mowat et al. 25). Population density was low near Golden but this is likely because the study area centered on the town of Golden where there are few grizzly bears (Boulanger et al. 24). A survey in the Central Selkirk Mountains suggested density was less than half in the southern portion of the study area where human density was much higher but habitat was similar (Mowat et al. 25). Population size in the Purcell Range appears to increase from south to north and this is likely due to the influence of human-caused mortality as well as habitat (Proctor et al. 27). Observed population size in the Purcell Range was much lower than a habitat based extrapolation. Recent population estimates north of Highway 1 in the Rocky Mountains and foothills of Alberta generated densities of about 5 bears/1 km 2 which precipitated a complete hunting closure in Alberta (Boulanger et al. 25a and b); these densities are also lower than predicted based on habitat quality and the differences between predicted and observed mortality were likely due to human impacts. In 23 a statistical model was used to predict population size for all grizzly bear populations in the Region to facilitate calculation of hunting quotas (Mowat et al. 24). This model has since been revised and the revised version was used to generate the most recent population predictions for the Region. Where available, inventory data were used to calculate quotas directly but the population estimates for the Elk and Flathead valleys may be lower than the true number. Early interpretations of the data from the Elk Valley generated a tentative population estimate of 65 bears; alternate interpretations of the data suggest the population size could be individuals (Boulanger 21). Subsequent hair and live-trapping in the south portion of this unit indirectly supported the larger estimates (Clayton Apps, personal communication). Recent fieldwork during summer 26 also suggests a larger population size (G, Mowat and L. DeGroot, unpublished data). The field based population estimate for the Flathead unit was also considered to be low based on anecdotal observations from hunters and researchers (B. McLellan, personal communication). 27

28 The current estimate of grizzly bear population size for the Kootenay Region is 2348 (Table G4) which is based on a combination of field based estimates and extrapolations. Kill rates for most hunted units are less than 3% of the current population estimate or extrapolation. Given observed levels of unreported mortality (McLellan et al. 1999), total recent mortality was likely less than 5% for all hunted units except the South Rockies and South Purcell units. The southern portion of the South Purcell unit was closed to hunting beginning 27 because human caused mortality exceeded sustainable levels; however much of this mortality was problem kills. The high mortality rate in the South Rockies unit is due to the large number of problem kills and possibly a low population estimate. A field based inventory project was begun in the South Rockies unit in 26 to monitor the impact of harvest on this population and reduce debate about harvest management. Harvest rate was slightly higher in the Flathead unit than other hunted units and a field based inventory is planned for this unit in summer 27 which should also help resolve issues around population size and sustainable kill levels. Kill levels are also modest for the populations that are closed to hunting but the southernmost populations have higher kill rates and it is possible that kill levels are not sustainable given the small and partially isolated nature of these populations. The Yahk, South Purcell and Kettle-Granby populations are of greatest conservation concern because known kill levels approach sustainable levels and unrecorded mortality may be high given the large number of human residents in these areas. Reducing problem mortality is likely the biggest challenge to conserving grizzly bears in the south portion of the Region. 28

29 Table G4. Grizzly bear mortality for Grizzly Bear Population Units in the Kootenay Region of BC during 22 to 26. The year previous (21) to this analysis there was no grizzly bear hunting in the Kootenay Region. GBPU Central Monashee Problem kills in past 5 years Hunter kills in past 5 years Average annual kills Population size Kill rate Reference for population estimate Mowat et al. 24; model revised 26 Central Purcell Proctor et al. 27 Central Rockies Mowat et al. 24; model revised 26 Central Selkirk Mowat et al. 25 Columbia- Shuswap - East Mowat et al. 24; model revised 26 Flathead Boulanger 21 Kettle-Granby Boulanger et al. 22; with subjective extrapolation North Purcell Mowat et al. 24; model revised 26 North Selkirk Mowat et al. 24; model revised 26 Rockies Park Ranges Mowat et al. 24; model revised 26 South Purcell Proctor et al. 27 South Rockies Boulanger et al. 22; with subjective extrapolation South Selkirk Proctor et al. 27 Spillamacheen Mowat et al. 24; model revised 26 Yahk Proctor et al. 27 Valhalla Mowat et al. 25 Kootenay Region Population extrapolation for

30 Literature Cited Apps, C. D., McLellan, B. N. and Woods, J. G. 26. Landscape partitioning and spatial inferences of competition between black and grizzly bears. Ecography 29: Boulanger, J. Estimates of black bear population size using DNA based mark-recapture, Upper Columbia River, British Columbia, Canada Report prepared for Mount Revelstoke and Glacier National Parks, Parks Canada, Revelstoke, BC. Boulanger, J., White, G. C., McLellan, B. N., Woods, J., Proctor, M., & Himmer, S. 22. A meta-analysis of grizzly bear DNA mark-recapture projects in British Columbia, Canada. Ursus 13: Boulanger, J., McLellan, B.N., Woods, J., Proctor, M.F., and Strobeck, C. 24. Sampling design and bias in DNA based capture-mark-recapture population and density estimates of grizzly bears. Journal of Wildlife Management 68: Boulanger, J.,G. Stenhouse, M. Proctor, S. Himmer, D, Paetkau, and J. Cranston. 25a. 24 Population inventory and density estimates for the Alberta 3B and 4B grizzly bear management area. Report Prepared for Alberta Sustainable Resource Development, Fish and Wildlife Division. Boulanger, J.,G. Stenhouse, G. MacHutchon, M. Proctor, S. Himmer, D, Paetkau, and J. Cranston. 25b. Grizzly Bear Population and Density Estimates for the 25 Alberta Unit 4 Management Area Inventory. Report Prepared for Alberta Sustainable Resource Development, Fish and Wildlife Division. Braumandl, T., D. Gayton and R. Stewart, Ecosystem Maintenance Burning Evaluation and Research (Ember) Pilot Project, Nelson Forest Region Clarke, R. 23. Characteristics of a hunted population of cougar in the south Selkirk Mountains of British Columbia. Final Report, Columbia Basin Fish and Wildlife Compensation Program, Nelson, BC. Felicetti, L.A., Schwartz, C.C., Rye, R.O., Haroldson, M.A., Gunther, K.A., Phillips, D.L., and Robbins, C.T. 23. Use of sulfur and nitrogen stable isotopes to determine the importance of whitebark pine nuts to Yellowstone grizzly bears. Can. J. Zool. 81: Gaynor, C, H. Van Ord, G. Mowat. 27. Predator Surveys within Kootenay Region Mountain Caribou Recovery Areas. Report for Ministry of Environment, Nelson, BC. Gunson, J. R Historical and present management of wolves in Alberta. Wildlife Society Bulletin 2: Gyug, L. W Assessment of grizzly bear populations, habitats and timber harvest mitigation strategies in the Boundary Forest District. Report prepared for BC Ministry of Environment, Penticton, BC. Harris, R. B. and L. H. Metzgar Harvest age structures as indicators of decline in small populations of grizzly bears. International Conference on Bear Research and Management 7: Hornocker, M An analysis of mountain lion predation upon mule deer and elk in the Idaho Primitive Area. Wildlife Monographs pp. Lambert, C. M. S., R. B. Weilgus, H. S. Robinson, D. D. Katnik, H. S. Cruickshank, R. Clarke, and J. Almack. 26. cougar population dynamics and viability in the Pacific Northwest. Journal of Wildlife Management 7:

31 Mattson, D. J., B. M. Blanchard, and R. R. Knight Yellowstone grizzly bear mortality, human habituation, and whitebark pine seed crops. Journal of Wildlife Management 56: Matson, D. J. and Merrill, T. 22. Extirpations of Grizzly Bears in the Contiguous United States, Conservation Biology 16: McLellan, B.N. 1989: Dynamics of a grizzly bear population during a period of industrial resource extraction. I. Density and age-sex composition. Canadian Journal of Zoology 67: McLellan, B. N Relationships between human industrial activity and grizzly bears. Int. Conf. Bear Res. And Manage. 8: McLellan, B.N., and Hovey, F.W. 1996: Estimating population growth of grizzly bears from the Flathead River drainage using computer simulations of reproduction and survival rates. Canadian Journal of Zoology 74: McLellan, B.N., Hovey, F.W., Mace, R.D., Woods, J.G., Carney, D.W., Gibeau, M.L., Wakkinen, W.L. & Kasworm, W.F. 1999: Rates and causes of mortality of grizzly bears in the interior mountains of British Columbia, Alberta, Montana, Washington, and Idaho. Journal of Wildlife Management 63: Miller, S.D., White, G.C., Sellers, R.A., Reynolds, H.V., Schoen, J.W., Titus, K., Barnes, V.G. Jr., Smith, R.B., Nelson, R.R., Ballard, W.B., and Schwartz, C.C Brown and black bear density estimation in Alaska using radiotelemetry and replicated markresight techniques. Wildl. Monogr. No Mowat, G. and C. Strobeck. 2. Estimating population size of grizzly bears using hair capture, DNA profiling, and mark-recapture analysis. Journal of Wildlife Management. 64: Mowat, G., D.C. Heard, and T. Gaines. 24. Predicting Grizzly Bear (Ursus arctos) densities in British Columbia using a multiple regression model. Progress Report. B.C. Ministry of Water, Lands and Air Pollution, Victoria, B.C. Available at: wlapwww.gov.bc.ca/wld/documents/gb_predicting_densities.pdf Mowat, G., D. C. Heard, D. R. Seip, K. G. Poole, G. Stenhouse and D. W. Paetkau. 25. Grizzly and black bear densities in the interior mountains of North America. Wildlife Biology 11: Poole, K. G. and G. Mowat. 22. Alberta furbearer harvest data analysis. Alberta Species at Risk Report No. 31, Alberta Fish and Wildlife Division, Edmonton. Proctor, M. and L. Neumeier Bear handling as a result of bear-human interaction in the Revelstoke, British Columbia are during Report for Ministry of Water, Lands, and Air Protection, Nelson, BC. Proctor, M.F., B.N. McLellan, C. Strobeck, and R.M.R. Barclay. 25. Genetic analysis reveals demographic fragmentation of grizzly bears yielding vulnerably small populations. Proceedings of the Royal Society Bulletin: 1-8. Proctor, M., J. Boulanger, S. Nielsen, C. Servheen, W. Kasworm, T. Radant, and D. Paetkau. 27. Abundance and density of Central Purcell, South Purcell, Yahk, and South Selkirk grizzly bear population units in southeast British Columbia. Report for BC Ministry of Environment, Nelson and Victoria, BC. Reynolds, C. K. 22. Upper Columbia River region black bears A DNA mark-recapture study. M. SC. Thesis, University of Alberta, Edmonton. 31