Effects of Relatedness on Spatial Distribution of Bobcats
Allison Reid, Warnell School of Forest Resources
Robert J. Warren, Warnell School of Forest Resources
Mike Conner, Joseph W. Jones Ecological Research Center
Relatives may benefit from each others fitness by way of shared genes, a phenomenon termed inclusive fitness (Hamilton 1964). Because of inclusive fitness, relatedness can impact social behavior (Hamilton 1964), and thereby has the potential to affect social structure and spatial distributions. Thus, kinship information among individuals may aid in explaining behavior toward one another (Ralls et al. 2001).
Several recent studies have examined relatedness along with spatial distribution and/or social structure in populations of black bears (Ursus americanus) (Schenk et al. 1998), gray wolves (Canis lupus) (Smith et al. 1997), African wild dogs (Lycaon pictus) (Girman et al. 1997), coatis (Nasua narica) (Gompper et al. 1998), banner-tailed kangaroo rats (Dipodomys spectabilis) (Winters and Waser 2003), kit foxes (Vulpes macrotis mutica) (Ralls et al. 2001), and raccoons (Procyon lotor) (Ratnayeke et al. 2002), all of which are either social and/or philopatric (young remain within or close to their natal area, see Ratnayeke et al. 2002). However, few studies of this nature have examined solitary, non-philopatric mammals. Only one study has examined the relationship between kinship and spatial distribution in a solitary felid, the bobcat (Lynx rufus), but preliminary results were inconclusive (Janecka, personal communication), leaving opportunity for further investigation.
Bobcats are apex predators in most of their range, particularly the forested ecosystems of the Southeast (Conner et al. 1999). Apex predators suppress medium-sized omnivores (hereafter mesopredator) populations, and the presence of apex predators prevent population explosions of mesopredators (Rogers and Caro 1998, Courchamp et al. 1999, Crooks and Soule 1999). By regulating mesopredator populations, apex predators increase prey survival (Rogers and Caro 1998, Courchamp et al. 1999, Crooks and Soule 1999). Thus, management of bobcats as top predators is vital to the proper management of other species (Conner et al. 1999). Equally significant to management, in 1975 bobcats were listed under Appendix II of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) (Anderson 1987, Conner et al. 1992, Woolf and Hubert 1998). This meant that before permitting export, member countries had to demonstrate that international trade would not be a detriment to bobcat survival (Woolf and Hubert 1998). In the U.S., each state is responsible under CITES for maintaining sustainable bobcat harvest (Anderson 1987). Therefore, an understanding of bobcat ecology is of value in making management decisions (Conner et al. 1992).
Because of the dearth of current knowledge on kinship and spatial organization in this species and its possible importance to bobcat management, this study will examine the relationship between kinship and spatial distribution in bobcats at the Joseph W. Jones Ecological Research Center in Baker County, Georgia, a longleaf pine/wiregrass ecosystem. Using telemetry data of bobcats at Ichauway and tissue samples from collared and newly trapped bobcats, DNA analysis will be utilized to determine relatedness between individuals, and the resulting kinship data will be compared to spatial organization of the bobcat populations. This research will also investigate levels of heterozygosity in harvested bobcat populations, using bobcats collected in a predator removal study.
An integrative study of social and reproductive systems in Northern Bobwhite (Colinus virginianus): a non-migratory, avian species bearing precocial young
Brant C. Faircloth, Warnell School of Forest Resources
John P. Carroll, Warnell School of Forest Resources
William E. Palmer, Tall Timbers Research Station
Large-scale, contemporary studies of social and reproductive systems of nonmigratory, avian species with precocial offspring are scarce. However, mating systems in these orders range from purported monogamy to exploded lekking, and parental investment strategies extend from mound incubation with no parental care to bi-parental care extending from birth to sexual maturation. The scarcity of reproductive and social system information among these species creates a gap in the study of breeding systems, both among avian species, specifically, and all organisms, generally. We propose the philopatric, non-migratory, and sedentary nature of many of these species creates the potential for these breeding systems to be driven by kin selection and elements of cooperative breeding. Therefore, study of non-migratory, precocial species is essential to filling the gaps with respect to the collective scientific knowledge of breeding systems, social systems, kin selection, and cooperative breeding.
In order to overcome barriers inhibiting prior study of these systems among non-migratory, precocial birds, two goals must be accomplished. First, integration of data sources and techniques from several fields must occur to allow objective collection and analysis of data. Second, the use of an abundant, easy to capture, model species is necessary to allow the efficient sampling of individuals and satisfactory sample sizes.
We will conduct our investigation by integrating data from molecular lab techniques (microsatellite analysis and genetic sex determination) with field data collected through radio-location and spatial data present in a geographical information system. We will investigate these systems by selecting the Northern bobwhite (Colinus virginianus), a non-migratory, gallinaceous species bearing precocial young, as our model species.
Our research objectives are to determine: the composition of Northern bobwhite social groups, the genetic relatedness within and between these groups and others on the landscape, and the temporal and spatial aspects of individual movements between and philopatry of social groups. We will also examine factors affecting reproduction in our model species by: observing the pairing of mates and the operational sex ratio throughout the breeding season; inferring parentage of individual offspring; assessing rates of extra-pair copulation, post-hatch brood amalgamation, and intraspecific nest parasitism; genetically determining the sex ratio of neonatal offspring; and assessing the influence of female condition on offspring sex ratio. Finally, we will combine our field and laboratory observations to: examine the effects of social group composition on demographic parameters, investigate the effect of offspring sex ratio on operational sex ratio, investigate the effect of operation sex ratio on reproductive strategies, and determine the mating system of the model species.
Ecology and Conservation Genetics of Mottled Ducks on Managed Wetlands
Guo-Jing Weng, Warnell School of Forest Resources
Sara H. Schweitzer, Warnell School of Forest Resources
Mottled ducks (Anas fulvigula) were introduced to the Santee River Delta and the ACE (Ashepoo, Combahee, and Edisto Rivers) Basin, South Carolina from Texas, Louisiana, and Florida during 1975-1982 for hunting opportunities. Released birds have established several local populations along the South Carolina and Georgia coasts. Dispersal of mottled ducks from South Carolina and Georgia is of great concern to ornithologists because of efforts to maintain the Florida mottled duck (A. f. fulvigula) as a distinct population. Our objectives are to study the life history, behavior, habitat selection, and population structure of South Carolina-Georgia mottled ducks and to detect gene flow (if any) between Florida and South Carolina-Georgia mottled duck populations. Study sites include Bear Island Wildlife Management Area (WMA) and Savannah Corps of Engineers Confined Disposal Facilities in South Carolina, and Savannah National Wildlife Refuge and Altamaha WMA in Georgia. Mottled ducks seldom used water deeper than 12 cm. Submerged plants and aquatic invertebrate abundance did not appear to be associated with habitat use of mottled ducks. All broods over 2 weeks of age survived to fledge. Ducks from hunters' harvest and feather samples from wildlife management agencies have been collected for genetic analysis. Microsatellite DNA will be used to investigate the level of gene flow within South Carolina-Georgia populations and among populations from Texas, Louisiana, Florida, South Carolina, and Georgia. The results of the genetic analysis will aid management policy and hunting regulations on mottled ducks.
Development of Methods for Monitoring and Assessing Population Status of Black Bears in Central Georgia
Jamie Skvarla, Warnell School of Forest Resources
Michael J. Conroy, Georgia Cooperative Fish and Wildlife Research Unit
The distribution of black bears (Ursus americanus) in the state of Georgia can be classified into three populations with an unknown amount of connectivity between the north, the south near the Okefenokee swamp, and the central portion of the state. The Ocmulgee River drain and its tributaries supports a unique population of black bears in central Georgia. This population is known to occupy large forested areas in portions of Bibb, Houston, Twiggs, Bleckley, and Pulaski Counties, an area of approximately 300" km2. Oaky Woods and Ocmulgee Wildlife Management Areas (WMA's) are likely the "core" area of suitable habitat for black bears in central Georgia with densities decreasing significantly as distance from large unfragmented forested area increases. The population density and status of black bears is currently unknown for this area.
The objectives of our study are to estimate population parameters (abundance, survival, and reproduction) and construct models for predicting viability and to assess the impacts of alternative harvest and habitat management policies.
Abundance will be estimated using a variety of mark-recapture markers (physical captures, camera "trapping", and genetic markers). Bears are physically captured on or near the WMA's and uniquely marked, fitted with radio-transmitters, and released into the population for recapture. Barbed-wire enclosures, or hair snares, are systematically placed on the WMA's for collection of hair. Hair samples will be analyzed using DNA from 8 microsatellite markers to determine individual identification. Additionally, digital cameras are randomly placed in conjunction with hair snares to monitor captures from marked and unmarked bears. Survival and reproduction will be estimated using data from radiotelemetry, den visits, physiological measures, and other approaches.