The following is a slightly edited version of a plenary address delivered at the Western Section annual meeting in January 2009. The plenary theme was “The view from the future: wildlife management challenges and opportunities of the next 100 years.” Key references are listed at the end of the address. Readers will also be interested in the Winter 2009 (Vol. 3, No. 4) issue of The Wildlife Professional, which contains a special section on the preparation and training of future wildlife professionals.
Recent assessment of pronghorn (Antilocapra americana) translocations and urban development projects has revived interest in the legacy of pronghorn in California. These issues are of increased public concern, especially development projects that impact scarce native grassland – habitat for the few remaining herds in southern California. Therefore, the scientific and popular literature for pronghorn in California was investigated with an objective of making this data readily available for concerned sources. More than 125 reports from 1769 (Bolton 1927, Crisby 2003) to 2009 were located. Although pronghorn were historically abundant in California, few remain today, and these are predominantly located on northeastern rangelands. The impact of insidious civilization developments appears deleterious to herds experiencing perilously low numbers south of San Francisco. The plight of these wild herds is apparently tied to the perpetuation of native grassland abundant with forbs. There is concern that if pronghorn are to remain a heritage on southern rangelands of the “Golden State,” that native grasslands need to be perpetuated in healthy condition – then it may be feasible to perpetuate native pronghorn populations.
Diurnal live trapping in desert environments requires thermal protection from high temperature extremes. However, internal trap temperatures under cardboard shades have not been reported in the literature. We tested 3 shade designs commonly used by biologists during diurnal trapping: two A-frame designs with different cardboard colors, brown and white, and a cardboard box tube. Trap shade treatments were tested from 21 April to 7 July 2007 with temperatures (°C) recorded hourly with a datalogger. There was no difference in internal trap temperatures between the shade configurations when ambient air temperatures reached approximately 30°C, but as the trapping season progressed, residual heat stored in the desert landscape led to higher internal live trap temperatures. TransacTions of The WesTern secTion of The Wildlife socieTy 44:1-3
There is a signifi cant need to determine the current status of the San Joaquin kit fox in the northern extent of its range. The last peer-reviewed account of this question was addressed in 1993. Here we report our fi ndings of an extensive literature review of the San Joaquin kit fox in the northern range and status conclusions extrapolated from these reviews. Possible reasons for lack of a robust kit fox population in the northern range may include lack of the preferred Heteromyid prey item, higher predatory pressures, and lack of new immigrant foxes from southern core populations. Various characteristics lead to this prediction; namely, the fox occurs at a high trophic level, ex- hibits a low population density, has a relatively slow life history, and utilizes a small geographic range isolated from larger populations. Other risk factors can be accounted for by anthropogenic activities that have an effect on the fox irrespective of the fox's ecology, charactering the northern range as a sink population for the San Joaquin kit fox and susceptible to localized extirpation. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 43:27-36; 2007
Our analyses of the kit fox sighting elements in the California Natural Diversity Database and other data suggest the possible misidentifi cation of coyote pups as kit fox. During the summer months, coyote pups look remarkably similar to adult kit foxes; both have black-tipped tails and large ears relative to the body size. As coyote pups grow, there is a period of time where the pup weight approximates that of an adult kit fox. With an average weight increase of about 0.31 kg/week, coyote pups are ~2 kg during June, July, and August. During this time, juvenile coyotes superfi cially resemble kit foxes during spotlighting sessions, and it may be challenging for biologists to differentiate coyote pups from kit foxes at a time when both are present on the landscape. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 43:37-42; 2007
Invasive vertebrate pests together with overabundant native species cause significant economic and environmental damage in the Australian rangelands. Access to artificial watering points, created for the pastoral industry, has been a major factor in the spread and survival of these pests. Existing methods of controlling watering points are mechanical and cannot discriminate between target species. This paper describes an intelligent system of controlling watering points based on machine vision technology. Initial test results clearly demonstrate proof of concept for machine vision in this application. These initial experiments were carried out as part of a 3-year project using machine vision software to manage all large vertebrates in the Australian rangelands. Concurrent work is testing the use of automated gates and innovative laneway and enclosure design. The system will have application in any habitat throughout the world where a resource is limited and can be enclosed for the management of livestock or wildlife.
Western populations of fisher ( Martes pennanti) recently were designated by the U.S. Fish and Wildlife Service to be a distinct population segmen t meriting listing under the federal Endangered Spe cies Act. Disease was noted in the designation as a pot ential issue affecting fishers, and this study prov ides information on exposures of a fisher population in the Hoopa Valley Indian Reservation to pathogens in northwestern California. Of 31 fishers sampled bet we n December 2004 and March 2005, 1 (3%) had been exposed previously to canine distemper virus ( CDV) and 13 (42%) had been exposed to canine parvovirus (CPV) . Although little is known about disease in fishers, both viruses can be transmitted via fecal contamination and other means, and CDV causes high rates of mortality in other mustelids. We recommend disinfecting traps and handling equipment b tween captures to minimize risks of spreading pathogens to fishers and other carnivores. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 42:40–46; 2006
We compiled and analyzed data from 1987 to 2004 on feral pig (Sus scrofa) population indices affected by control methods at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai`i. These population data included annual sign surveys, the number of pigs removed from fenced management units, and age and reproductive status from necropsies. There was an even sex ratio (1 female:1.02 males) within the population and within age classes. Boars lived to 60 months while sows lived to 48 months. Pregnancy occurred throughout the annual cycle, but lactation peaked in April– June. Reproductive rates also increased with age, peaking at 2–4 years in sows. We reconstructed the standing population within a 2,024-ha closed unit to examine demographic processes. We estimated that annual removal of >41–43% of the population was necessary to affect a decline. Annual sign surveys showed a strong and sustained decline in pig activity after 1997 relative to unmanaged areas. When compared with staff or public hunting, snaring was the most efficient control method. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 42:53–67; 2006
The Alameda whipsnake (Masticophis lateralis euryxanthus) is a threatened subspecies for which recovery to non-threatened status is a goal. Information on the whipsnake’s natural history is currently limited and efforts are underway to identify habitat requirements that may contribute to the recovery of this snake. From publicly available data and our own observations, we determined that the Alameda whipsnake has been observed in a very wide range of habitat types, which is contrary to that currently documented. We believe that this information can be used to assist recovery of this subspecies. Increased knowledge of more varied habitat use by Alameda whipsnakes may increase the possibility of the preservation of available adjacent habitats and facilitate connectivity between patches of core habitat. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 41:21-25; 2005
Nest predation can greatly affect reproductive success of waterfowl. We studied factors influencing duck-nest predation near Humboldt Bay in northern California by testing the prediction that measurements of nest concealment and nest location should differ between successful and depredated artificial nests. We ran a priori hypothesized logistic regression models to evaluate the effects of nest concealment and nest location variables on the fate of all nests, and, for depredated nests, on the type of egg loss. The best-fit model for nest fate included lateral cover and study site variables. Among depredated nests, the best-fit model for the type of egg loss (broken or removed) included vertical cover, study site, and broad habitat. Best-fit models for nest fate and type of egg loss did not include local vegetation, distance to trail, or distance to water. Our results suggest that nest concealment influenced both the likelihood of nest predation and the type of predator to which a nest is vulnerable. We recommend that managers work to maximize opportunities for nest concealment and researchers determine locally important predators in future study designs. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 41:11–20; 2005
The California Wildlife Habitat Relationships (CWHR) system includes a habitat classification system and habitat suitability models for the approximately 650 species of terrestrial vertebrates that use these habitats. We created a computer model for grouping these species into guilds based on how the habitat suitability of forest-dwelling wildlife is predicted by CWHR to respond to changes in average tree diameter and percent forest canopy cover. We found that the largest bird guilds in Sierran mixed conifer habitat were: (1) species for which reproductive and cover habitat quality improved as average tree size increased; (2) species for which foraging habitat quality worsened as forest canopy cover increased; and (3) generalist species that showed no substantial change in habitat quality with respect to a particular life function as average tree size or forest canopy cover increased. We found that the predicted responses by the guilds from the model were generally consistent with several published lists enumerating species’ sensitivities to habitat changes comparable to that modeled for the guilds. In conclusion, we suggest that our model may provide a useful tool for elucidating general biodiversity patterns in cumulative impacts and landscape resource assessments. TRANSACTIONS OF THE WESTERN SECTION OF THE WILDLIFE SOCIETY 41:1-10; 2005
A series of case studies conducted in Colorado, Arizona, and Utah have shown that vegetative regeneration of declining aspen (Populus tremuloides Michx.) can be initiated through manipulations that provide three critical elements defined as the aspen regeneration triangle: 1) hormonal stimulation, 2) proper growth environment, and 3) sucker protection. Results of the studies used to formulate this treatment model are presented along with recommendations for innovative treatments to restore aspen in landscapes where it is rare or in decline. Soils and site productivity, competition from other plants, and the potential impact of browsing animals upon new regeneration should all be considered. Choosing a course of action depends upon a careful evaluation of the size, vigor, age, and successional status of candidate aspen clones. Treatments may include doing nothing, removal of existing aspen trees, removal of competing vegetation, prescribed burning, mechanical root stimulation, and browse protection.
Total nonstructural carbohydrate (TNC percent dry weight) of various tissues was monitored overwinter in four aspen (Populus tremuloides Michx.) clones in central Colorado. Midwinter TNC was highest in root phloem, followed by bark, small roots, root xylem and stem sapwood respectively. Photosynthates were not immediately translocated to roots with the onset of dormancy, but persisted in bark, possibly due to photosynthetic activity, throughout the fall before being transferred to root phloem tissue in mid to late winter. Small roots and woody tissue do not appear to play a significant role in carbohydrate storage. These TNC allocation patterns may help explain seasonal aspen herbivory, particularly the stripping of bark by deer, elk and moose in winter.
