| Abstract/Description or Keywords |
A preliminary reconnaissance-level study of the western toad (Anaxyrus boreas) was conducted at Fish/Bear Lakes from May 3 - October 15, 2015. The study area is partly on Crown land, with three large parcels of private land that occupy major toad habitat areas and migration routes. Highway 31A and the Wagon Road recreation trail are the two public motorized corridors through the study area. The study was funded by the small grant program of the Fish and Wildlife Compensation Program (FWCP), with some supplemental support from the Valhalla Wilderness Society. A choice was made to spread the small budget to cover field sampling throughout the spring-to-fall toad season as part of the pilot study. This resulted in the best preliminary results possible but with small sample sizes such as for adult toad mortality surveys. A high level of coordination and excellent cooperation was experienced with the BC Ministry of Transportation and Infrastructure (MoTI) and BC Ministry of Forests, Lands and Natural Resources Operations (MFLNRO) – FWCP section. Opportunistic public education occurred throughout the study, including a large interpretive sign and hand-outs at the Fish Lake rest stop. The largest land owner was contacted and appraised of the project throughout the study period. The owner of the other two private parcels will be contacted in 2016. The Fish/Bear Lake study design and implementation benefitted from the research and helpful input of biologists involved with the FWCP western toad project at Summit Lake. Jakob Dulisse was an advisor to our study and carried out the breeding site surveys at Fish Lake. Our main 2015 field findings were as follows: _ Our study confirmed that western toads in our study area have the same three traditional migrations as reported at Summit Lake (Dulisse 2015) and elsewhere: adult spring migration to breeding lake, post-breeding dispersal away from lake and large toadlet (metamorph) summer migrations to terrestrial habitat. Adults migrated at night while toadlets migrated during the day. Toadlet migrations in 2015 appeared correlated to summer rain events as previously observed in 2014. _ Fish Lake was identified to be a major western toad breeding lake of likely regional significance; with lesser breeding at Bear Lake. Toadlets were on average small and approximately one-half the size of toadlets reported at Summit Lake. Toad and toadlet numbers were impossible to estimate but in early May adult toads were very numerous in Fish Lake and later in the summer toadlets would number in the hundreds of thousands. _ Adult Breeding: When the study commenced on May 6 the lake ice had already melted and high numbers of adults were observed in Fish Lake. Studying the lake surface with binoculars at twilight confirmed a very high level of adult crepuscular activity not observable during the day. Adults in amplexus (breeding position) and egg laying was already underway. Surveys on May 13 identified three main breeding/egg mass areas at Fish Lake along the north and west shore. This data would appear to fit the pattern with that reported in the scientific literature of an “explosive” breeding strategy at communal breeding sites where large numbers of adults aggregate over a 1- or 2-week period. In this case the first two weeks of May would appear to the prime migration and breeding time. _ Adult toad migration on Highway 31A: Twenty-seven segments for live and dead adult toads were established along 2.3 km of Highway 31A from the east end of Fish Lake to just beyond the west end of Bear Lake. Thirteen night-time walking or drive-by surveys recorded a total of 133 live adult toads crossing the highway between May 6 and July 19, 2015. Of the four sub-areas, the majority of live adults (N = 115) were found on highway segments 1-2 to 11-12 along the north side of Fish Lake, with smaller numbers elsewhere. The highest road counts of live adults were between May 6 and May 16, 2015, when an average of five counts showed 21.6 live adult toads/night survey. For the latter part of May, three counts showed a drop to 5.3 adult live toads/night survey. Counts in June and until July 19 showed only a small amount of adult toad night-time activity in relation to Highway 31A. _ Adult toad mortality on across Highway 31A: Between May 6 and October 14, 2015, a total of 34 daytime walking and drive-by surveys were made to locate adult toads dead on the road (DOR) along the 2.3 km transect on Highway 31A. During this period, we documented a total mortality of 45 adult toads: 17 females, 7 males and 21 unidentified. As to be expected, the highest total traffic mortality recorded (34) for the spring period and overall survey season was on the north side of Fish Lake, where the most live adult toads were also recorded crossing. The highest number of dead toads also corresponded fairly well with the segments where the highest number of migrating adults were counted. Of the 45 adult toad deaths recorded, the highest number (26) was during the first two weeks of May, corresponding to the period of the highest number of adults recorded crossing Highway 31A. After this, mortality dropped off considerably, corresponding well with the cessation of the breeding season. _ Timing of tadpole-toadlet metamorphosis and staging areas: Metamorphosis from tadpole to toadlet appeared to commence around July 15 and continue for approximately one month. Tens of thousands of toadlets staged in large aggregations, mostly at the three main breeding sites 1, 2, and 3 at Fish Lake. These sites are characterized by a shallow shoreline with some emergent vegetation and dense shoreline shrub or low vegetation cover. _ Toadlet migrations: Toadlet migrations from Fish Lake were observed to occur in daytime and to stage from the three main breeding/aggregation sites, with each having a different migratory route. Timing of migration may have been synchronous from each of the staging areas, for example, when mass movement was triggered by rain events during hot weather; or perhaps by persistent wet and cold weather later in the season when the need to migrate to the uplands to hibernate would have been more urgent for later developing metamorphs. The one-month metamorphosis period would help explain why we recorded at least 4 different migration events by toadlets away from Fish lake. _ Some toadlet migrations away from Fish Lake did not cross Highway 31A. Where they did cross the pavement, primarily at the breeding area 1 (Fish Lake rest stop – segment 1-2) and once at breeding area 2 (segment 4-5), the daytime migration events coincided with the high daily level of tourism traffic, resulting in considerable but unmeasured mortality. _ The 4 toadlet migration events at the Breeding Area 1 (Fish Lake rest stop) were July 20, July 27-28, August 5-12 and August 24. All toadlets had disappeared from the staging are by August 30. Pathways of the four migrations away from the rest stop did not vary in July, but in August varied in subtle but significant ways that will eventually have some relevance to any proposed mortality mitigation measures. During July, the metamorphs travelled en mass east through the rest area (when tourists were often present) and then crossed the highway northeast. Toadlets during the two smaller migration events in mid- and late August tended to travel more eastward and not cross Highway 31A at the rest stop. _ Breeding Area 2 (middle lake) toadlets, despite high aggregations, had only one documented migration event north across the highway on July 27. Other than this date, even when Breeding Area 1 (rest stop) toadlets were migrating en mass across the highway in 2014 and 2015, no middle lake toadlets were observed on the highway. This needs to be more carefully monitored in 2016. _ Breeding Area 3 (west end of lake) had the largest number of toadlets that migrated mostly to the west and south-west through the large wetland/shrub zone and on an ATV road, with only a few appearing to move north across highway 31A. Migration events occurred on July 27-28, and from August 15-16 to perhaps August 24. All migration events here appeared to be over by August 30. Migration events may have occurred on July 20, and the August 15-16 one may have started as early as August 5. All toadlet activity here occurred on private land. _ Overall highway mortality to migrating adults and toadlets in 2015 was considered to be an important conservation concern. Experimental mitigation: With the assistance of Summit Lake toad biologists, we used our preliminary research results to study feasible ways to mitigate the population threat from the road kills, such as culverts and underpasses. This included an experimental directional fence with a temporary wooden bridge to test if migrant Fish Lake toadlets would cross under the nearby Goat Creek highway bridge. We found they did. Some ad hoc bucketing of toadlets was done and we found some locals coming and doing this on their own. Recommendations: The study team recommends at least another two years of research that expands surveys to Bear Lake and peripheral transect areas, continued coordination with MoTI and FWCP-MFLNRO, continued high level of public education, and greater coordination with surrounding landowners and adjacent rail-to-trail managers. The team also recommends working with MFLNRO-FWCP on a conservation plan to address all issues related to the toads, including protection of core wetland and core terrestrial habitats, recreational motorized impacts, private land, logging, and others. |
