Christine A. Bishop

Effectiveness of Short-Distance Translocation and its Effects on Western Rattlesnakes

Abstract Short-distance translocation (SDT) is commonly used to mitigate snake–human interactions, yet little is known about its effectiveness or its effects on behavior and welfare of snakes. Between April 2004 and October 2005, we evaluated SDT as a conservation and management tool by investigating how 500-m SDT affected spatial ecology, body condition, and behavior of western rattlesnakes (Crotalus oreganus) surgically implanted with radiotransmitters in a field study near Osoyoos, British Columbia, Canada. Of 14 rattlesnakes subjected to SDT, 12 (85.7%) returned on ≥1 occasion (range 1–7 times) to the general area they were removed from. Rattlesnakes that underwent SDT showed an increase in total distance moved over an active season compared to non-translocated snakes, but there was no evidence to suggest SDT had an effect on activity range size. There was no evidence to suggest SDT affected body condition, behavior, or mortality rates. Short-distance translocation to high-quality undisturbed habitats was unsuccessful as a long-term solution to snake–human conflict because most translocated snakes returned to conflict areas within a short time (x̄ = 19.9 ± 8.7 days). However, SDT may be an effective short-term tool to manage snake–human conflict in areas where human presence is seasonal or short-lived if careful attention is paid to species-specific biological needs, habitat quality at the release site, and the location of the release site in relation to conflict areas.

Wildlife Ecotoxicology: Forensic Approaches

This introductory chapter provides an overview of the book and some discussion of the emergent themes. The nature of forensic ecotoxicology is considered, and a definition proposed. We reflect on the experiences of some authors in trying to translate scientific evidence of toxicant effects into regulatory or non-regulatory action. We further examine the problem of bias in data interpretation, and consider some of the dispute resolution processes discussed by the various authors.

Hatching success and pesticide exposures in amphibians living in agricultural habitats of the South Okanagan Valley, British Columbia, Canada (2004-2006).

In 2004 to 2006, in the Okanagan Valley, British Columbia, Canada, we measured pesticides, water chemistry, and hatching success of Great Basin spadefoot (Spea intermontana), Pacific treefrog (Pseudacris regilla), Western toad (Bufo boreas), and Columbia spotted frog (Rana luteiventris). Predator-proof cages containing Gosner Stage 4 eggs were placed in ponds in nonagricultural reference sites in conventionally sprayed and organic orchards. Seventeen pesticides were detected in ponds in sprayed orchards but occurred at low concentrations (ng/L) except for diazinon (1,410 ng/L). Chloride, sulfate, conductivity, nitrate, and phosphorus showed significant differences among sites. Spadefoot mean hatching success ranged from 0 to 92% among sprayed orchards, whereas the range was 48 to 98.6% among organic orchards and 51 to 95.5% among reference sites. Mean hatching success for Pacific treefrog was 22.1 to 76.1% among sprayed orchards, whereas the range was 83.4 to 97.1% among reference sites. Although sample sizes were small and replication was low, we found that trends in hatching success of eggs of Western toad and Columbia spotted frogs were consistent with the other species. Variables that correlated negatively with amphibian hatching success included 12 pesticides and seven water chemistry parameters. However, stepwise regression found that, in 2005, atrazine accounted for 79% of the variation in spadefoot hatching success and, in 2006, atrazine, total nitrate, and chlorpyrifos accounted for 80%. For Pacific treefrog there were no significant correlations with pesticide concentrations; rather, hatching success correlated with water chemistry parameters. The present study also emphasizes the variability in species sensitivity and importance of incorporating water chemistry into the interpretation of water quality for amphibians.

Relative abundance, age structure, and body size in mudpuppy populations in southwestern Ontario

ABSTRACT Little is known of mudpuppy (Necturus maculosus) population structure and ecology; some populations in the Great Lakes are thought to be in decline. Mudpuppies are the obligate hosts for the mudpuppy mussel (Simpsonaias ambigua), a species that is endangered in Canada and in many Great Lakes states. We surveyed mudpuppies from the Sydenham River, the only known Canadian locality of the mudpuppy mussel, in order to generate information on relative density, deformity rates and population age/size structure and used this information to compare them to known mudpuppy populations from Great Lakes sites in the Detroit River, Lake St. Clair and Long Point in Lake Erie. Deformity rates were elevated at some sites in the Sydenham River. The relative density of mudpuppies in the Sydenham River was lower than that of other Great Lakes sites and their age was skewed towards younger individuals. Although at lower densities than at other Great Lakes sites, the mudpuppy population in the Sydenham River appears stable and is showing signs of recruitment which bodes well for the future of the mudpuppy mussel population of the river.

Habitat Characterization of Breeding Territories of the Western Yellow-Breasted Chat in the South Okanagan, British Columbia, Canada

Abstract From 2002 to 2007 we measured breeding territory, nest patch, and nest shrub characteristics for Yellow-breasted Chats (Icteria virens auricollis) in the northern edge of their distribution in British Columbia, Canada. Surveys were done at 94 breeding territories, 238 nest patches, 246 nest shrubs, and at random locations for comparison. Habitat selection by chats was not random, and territories were selected for specific vegetation characteristics. Chat breeding territories were located in lower elevation riparian zones consisting mainly of dense shrubs and early successional water-tolerant trees, with the dominant shrub species being wild rose (Rosa spp.). Chats nested in 12 plant species and 72% of nests were within wild rose, which was also the dominant species in 5 m and 11.3 m radius nest patch plots centered at the nest shrub. Based on georeferenced locations of male chat singing or perching locations, chat breeding territories were on average 0.37 ha (s  =  0.27 ha) in size (n  =  66).

Contaminant concentrations and biomarkers in 21-day old Herring Gulls (Larus argentatus) and Double-crested Cormorants (Phalacrocorax auritus) from eastern Lake Ontario, and from Hamilton Harbour in western Lake Ontario in 1989 and 1990

This study measured concentrations of polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, trace metals and biochemical markers of contaminant exposure and potential toxicity (plasma and hepatic retinol, hepatic retinyl palmitate, ethoxyresorufin O-deethylase, hepatic porphyrins) in 21 day-old Herring Gull (Larus argentatus) and Double-crested Cormorant (Phalacrocorax auritus) chicks. The chicks were collected from breeding colonies at Hamilton Harbour, an industrialized site in western Lake Ontario, and at Snake and Pigeon Islands in eastern Lake Ontario in 1989 and 1990. The polycyclic aromatic hydrocarbons, benzo[a]pyrene and naphthalene, were detected in bile and concentrations were higher in both species, but particularly in Cormorants, at Hamilton Harbour in comparison to eastern Lake Ontario. Ethoxyresorufin O-deethylase activity correlated positively with polyaromatic hydrocarbon exposure in Cormorants. At Hamilton Harbour, Cormorants had significantly greater liver to body weight ratios, increased hepatic ethoxyresorufin O-deethylase activities and elevated plasma retinol concentrations compared to those from eastern Lake Ontario. Liver concentrations of selected polychlorinated biphenyl congeners were generally low (<2 ug g−1 w.wt) in birds from both areas but Hamilton Harbour Herring Gulls had mean concentrations that were significantly higher than eastern Lake Ontario Gulls, while Cormorants had low and similar polychlorinated biphenyl concentrations between sites. Trace metal levels did not vary substantially between sites for either species.

The Rocky Mountain Arsenal: From Environmental Catastrophe to Urban Wildlife Refuge

In 1942, the US Army purchased 70 km2 near Denver, Colorado, to construct the Rocky Mountain Arsenal, where they manufactured chemical and incendiary weapons (mustard, lewisite, napalm) in support of the war effort. After World War II, Shell Oil and its predecessors manufactured pesticides, insecticides, and herbicides at the Arsenal, and the Army manufactured and then decommissioned Sarin (GB) nerve agent. The industrial manufacturing was concentrated near the center of the site, with many square kilometers of undeveloped land providing a buffer from urban Denver. Millions of liters of liquid wastes, including cyclodiene pesticides, such as dieldrin, aldrin, and endrin, were disposed of in open basins, pits, and trenches on the site. Cyclodiene pesticides impact the central nervous system of exposed biota, causing disorientation, emaciation, and eventually death. Thousands of wildlife mortalities were documented at the site, including an estimate of 20,000 duck deaths over a 10-year period in the 1950s, and over 1,800 waterfowl deaths in one basin alone between 1981 and 1987. After manufacturing ceased in the 1980s, the Army, Shell, the US Environmental Protection Agency, and the State of Colorado endeavored to address the contamination and the Arsenal’s future land use. In 1992, the USA passed the Rocky Mountain Arsenal National Wildlife Refuge Act to create wildlife habitat from uncontaminated and remediated areas and reduce risk of exposure to humans. Many aspects of the cleanup were based on pesticide risks to wildlife, and the parties rarely reached agreement on cleanup thresholds and the amount of area requiring remediation. Ultimately, in 2010, after nearly 30 years of investigation and cleanup efforts and over

The influence of water quality on the embryonic survivorship of the Oregon spotted frog (Rana pretiosa) in British Columbia, Canada.

2 billion, “significant environmental cleanup” was completed. Millions of metric tons of toxic sludges and soils had been placed in hazardous waste landfills, and millions of metric tons more were buried in place and capped. The refuge now comprises approximately 6,000 ha, roughly the size of Manhattan. The cleanup process was contentious, resulting in multiple lawsuits, which is not a model that the authors recommend. Although contamination at the Arsenal likely is still present and should continue to be evaluated, the refuge will be an important protected oasis of wildlife habitat in the midst of the Denver urban sprawl.

Conservation of herpetofauna in northern landscapes: Threats and challenges from a Canadian perspective

In Canada, the Oregon spotted frog (Rana pretiosa) is a critically endangered species with only three known populations and an estimated breeding population of less than 400 located in isolated sites in the extreme south-west corner of British Columbia. Floating Nitex cages were used to assess embryonic survivorship in two populations of Oregon spotted frogs from 2002-2005. One population, near Aldergrove, BC experienced declines in population size while the other population, at Maria Slough, increased during the period 1997-2001. During embryo development, we measured trace metals, nutrients and physical parameters in the water at each site. These were used to test the hypothesis that water quality parameters were correlated with embryonic survivorship. During the study period in the declining population at Aldergrove R. pretiosa bred at two distinct sub sites (A and B) located 500 m apart within the wetland. Mean embryonic survivorship varied from 9% to 36% at sub site A and from 78% to 88% at sub site B whereas in the population in Maria Slough, the mean embryonic survivorship varied from 77% to 84%. Sulphate was the only water chemistry variable that differed significantly between the two study sites and was the highest at Maria Slough. A weak significant positive correlation was found between chloride and embryonic survivorship and conductivity and embryonic survivorship. A multiple regression model found conductivity was the only significant variable. We concluded that natural water chemistry conditions of low chloride and consequently low conductivity may be contributing to low embryonic survivorship in the population of R. pretiosa at MD Aldergrove, BC.