Biodiversity Guide - The Intertwine

egional conservation strategybiodiversity guideChapter 5 Fish and Wildlife of the Regionmost severely affected. The decreasing acreage ofoak habitats, grasslands, and shrublands raisesconcern for local populations of northern alligatorlizard, southern alligator lizard, racer, andring-necked snake.Furthermore, all of the region’s reptile speciesare affected by collection for pets, road mortality,predation by non-native species, and disturbancethat interferes with basking and nesting. Gartersnakes and alligator lizards are particularly susceptibleto predation by house cats, as they oftenlive in wood piles or house foundations. Vehiclescause mortality, particularly when reptiles movebetween basking, breeding, and overwinteringsites. Gopher snakes are mistaken for rattlesnakesand killed. Disturbance by hikers, unleasheddogs, bikers, and rock climbers can limit criticallyimportant basking time for many reptiles. Thesecretive behavior of the ring-necked snake andrubber boa makes it difficult to understand factorsthat could threaten their populations.Climate change models forecast earlier runoff ofrivers, drying of ponds, and warming temperatures.Although many snake and lizard speciesmay not be affected by these changes, the moreaquatic species would be. The native turtleswould lose productive summer habitat, includingshallows with aquatic vegetation that are criticalfor hatchlings and small juveniles. If ponds dryearly and strand frog tadpoles, both habitat anda major food resource for common garter snakesand western terrestrial garter snakes would belost. Warmer temperatures may skew sex ratiosin turtle populations because gender is determinedby nest temperature during early stagesof egg development.Conservation Strategy Species: Habitat Needs,Threats, and OpportunitiesThe Oregon Conservation Strategy and Washington’sComprehensive Wildlife ConservationStrategy designate four reptiles as species ofconcern: western pond turtle (in both states),western painted turtle (in Oregon), and the racerand the gopher snake (in Washington, PugetTrough only) (see Appendix E). Both turtlespecies live in ponds, lakes, and slow-movingstream channels. Within aquatic habitats, thesespecies need logs and other sites for basking,which is critical to thermoregulation for effectiveforaging and the production of eggs. However,these turtles also require nearby, sparsely vegetatedupland areas for nesting, such as grasslands,oak savanna, or openings in riparian forests. Inaddition, the western pond turtle winters in oakor riparian woodlands. Both of the snake speciesoccur in grassland habitats and require communalwinter den sites.Both turtle species have suffered from thefilling and draining of wetlands for agricultureand development. Remaining aquatic habitats aredegraded by pesticides and pollutants. Invasivereed canarygrass has choked many open-watersites, while exotic blackberry species shadenesting sites and hamper movement on land.Non-native turtles compete with native speciesand infect them with diseases and parasites.Non-native fish and American bullfrogs preyon turtle hatchlings and small juveniles, andunleashed dogs kill and disturb adults. Raccoonsand coyotes, albeit native species, are at relativelyhigh densities in urban areas; these animals preyon turtles and dig up nests to eat their eggs. Atmany western pond turtles sites there is little orno successful nesting or recruitment of juvenilesinto the population, so the population consistsmostly of adults. When female turtles are nestingor moving to and from nesting habitats, they areparticularly vulnerable to predation, disturbance,vehicle mortality, and illegal capture for pets.Both the racer and the gopher snake have lostgrassland habitats in the Portland-Vancouverregion and are vulnerable to road mortality andagricultural and landscaping practices. In addition,gopher snakes and occasionally juvenileracers are killed because of their resemblance topoisonous rattlesnakes.Priority Conservation and Restoration Strategiesn Continue to restore aquatic and upland habitats(includes enhancing water quality), especiallyat important areas for native turtle, i.e., SauvieIsland, the Columbia Slough, and other naturalareas along all rivers in the region. High-quality,appropriate connecting corridors and wildlifecrossings are important for reptiles and amphibiansbecause these animals generally do not movevery fast or very far.n Provide key habitat features for reptiles, such aslarge logs for turtle basking (both now and in thefuture), various sizes of woody debris (i.e., logsand smaller debris), and rocky outcrops.n Control invasive species.n Educate the public about area closures toprotect turtle nesting, controlling dogs, the needto restrict raccoon and coyote access to pet foodand garbage, and the importance of leaving nativeturtles in the wild and pets in captivity; this latterpoint may need to be backed up with regulationsand enforcement.Current Activities and ProgramsConservation assessments and strategies forreptiles in the region have focused on nativeturtle species (see “For More Information”).Conservation assessments for the western paintedturtle and western pond turtle in Oregon werecompleted in 2009, and the Washington Departmentof Fish and Wildlife wrote a state recoveryplan for the western pond turtle in 1999. Seattle’sWoodland Park Zoo, the Washington Departmentof Fish and Wildlife, the U.S. Forest Service,and the Oregon Zoo developed a program forwild-caught hatchling pond turtles to be raisedin captivity and released when large enough toavoid most predation. Since 1990, more than1,500 pond turtles have been reared in zoos andreleased into the wild.The Lower Willamette Valley Turtle WorkingGroup and the Western Pond Turtle RecoveryProject are partnerships among local, county, andstate jurisdictions and nonprofit groups. Theyhave shared goals of implementing conservationassessments and recovery plans and sponsoringresearch into limiting factors.Besides efforts for reptiles designated asconservation strategy species in the OregonConservation Strategy and Washington’s ComprehensiveWildlife Conservation Strategy, a primaryobjective is to keep currently common speciesfrom becoming rare. Educational efforts shouldfocus on protecting known nesting and overwinteringsites, re-creating such habitats, reducinginvasive species, providing rocks and logs forbasking and cover, and controlling domestic catsand dogs. Another key is educating the public toleave native turtles, snakes, and lizards in the wildand refrain from releasing non-native reptiles tothe wild.Questions, Unresolved Issues, and Data GapsAppendix H includes a list of current researchneeds by species. In addition to general habitatand range information, data on the impacts ofdiseases spread or introduced by invasive species,impacts of predators, and population genetics forthe region’s native turtles and lesser known snakesand lizards would greatly increase our ability tomanage local reptile populations. To accuratelygauge current threats to native reptile populations,an overall focus is needed on increasingthe body of knowledge of basic life history, rangeextents, and habitat.92 93