of the Ph.D. thesis Autor: Jan Matějů Name: Sociality and ecology in ground squirrels (tribe Marmotini) Ground-dwelling squirrels are parafyletic group of rodents from the family Sciuridae (tribes Marmotini and Xerini). Ground-dwelling squirrels are semi-fossorial inhabitants of treeless biotopes. They share most aspects of general biology. They usually breed once a year, have exclusively diurnal activity and are omnivorous. On the contrary, ground-dwelling squirrels display different levels of sociality, which makes them an ideal model to study different ecological aspects connected with evolution of sociality. The first part of the Ph.D. thesis is focused on the relationship between sociality and sexual size dimorphism and relative and absolute size of brain. At first, supposing that different levels of sociality are connected with differences in intensity of sexual selection acting on males, we tested association between sociality and sexual size dimorphism as well as association between sexual size dimorphism and body size - so called Rensch rule. Next, we tested correlation between sociality and relative brain size. In agreement with the Social brain hypothesis, we assumed that e.g. solitarily living species should have smaller relative brain size than species living in stable pairs. We found...

Utah prairie dogs (Cynomys parvidens) have been extirpated in 90% of their historical range. Because most of the population occurs on private land, this threatened species is continually in conflict with landowners. The Utah Division of Wildlife Resources has been relocating prairie dogs from private to public land since the 1970s, but relocations have been largely unsuccessful due to high mortality. Prairie dogs are highly social animals, but they are usually relocated without regard to their family group (coterie). I hypothesized that relocating Utah prairie dogs with their social structure intact may positively affect their survival rates and behavior. Utah prairie dogs were relocated from the golf course in Cedar City, Utah to two prepared sites near Bryce Canyon National Park, Utah in 2010 and 2011. Trapped animals were individually marked, and released at the new sites. Prairie dogs were relocated as coteries, or in a control group as randomly trapped individuals. To compare the two sites, vegetation transects were established at each site to document differences in composition and structure. Two months after relocation, traps were set to recapture released animals. Activity budgets were collected prior to, and following, relocation. Activity data were also collected on wild prairie dog populations for comparison. The best predictor of survival and recapture rate was the animal’s weight at initial capture. Larger animals had higher survival, but lower recapture rates. More research is needed to determine if this is due to better body condition, older animals having more experience, or both. Analysis showed no evidence of an advantage to relocating Utah prairie dogs by coteries. There was no benefit to survival, and no difference in behavior between coterie and control relocation strategies. Relocated animals behaved differently from non-relocated prairie dogs. While still significantly different, relocated individuals behaved more like wild prairie dogs than the animals at the urban source population. The vegetation at the two sites was significantly different. One site had significantly less grass cover, more invasive plant cover, and rockier soils. The sites also had different soil structures, which affect burrowing, and long-term retention rates. More research is needed to determine how site selection influences long-term success of a relocation site.

The black-tailed prairie dog (Cynomys ludovicianus) has experienced dramatic declines over much of its historical range due to habitat loss, plague, poisonings, and shootings. Many populations now occur as isolated genetic relicts. A multiple locus genetic profile was obtained using microsatellite analyses of six polymorphic nucleotide repeats from 319 black-tailed prairie dogs collected from 16 colonies throughout the state of Texas. This assessment revealed that existing populations have sufficient variation at all six loci to verify the usefulness of this approach as a primary genetic tool in conservation and preservation. The data reveals regional-dependent frequency patterns as well as support for founder/bottleneck effects for several of the 16 sites. Although the prairie dog population in Texas as a whole may appear genetically diverse, considerable genetic divergence has already occurred among the subpopulations (FST = 0.164). Isolation by distance is supported by genic differentiation analysis (P < 0.001) and pairwise correlation analysis between genetic distance and geographic distance (P < 0.001). Prairie dogs from six (COC, LUBA, LUBC, LUBD, LUBE, and TAR) of the original 16 sites have been relocated or exterminated, or were in the process of being relocated. Results indicated the following colonies (COT, DAL, HOW, and HUD) are of sufficient size and possess ample genetic diversity to be characterized as candidate foundation populations for future preservation efforts. The proximity of small colonies (< 20 hectares) such as HEMB, LUBB, and PEC, to other colonies should be examined to determine if they are isolated or part of a metapopulation. Colonies (HAR, HEMA, and SCH) with low genetic diversity would be ideal candidates for supplementation. Alternatively, these colonies could be relocated or blended with other similar but genetically distinct colonies. Baselines for healthy, pet prairie dog hematology and blood chemistries were also established. Results signify that data gathered from pet prairie dog blood analyses should be referenced against hematology and blood chemistry baselines established using pet prairie dog subjects.

Master of Science / Department of Biology / Jack F. Cully, Jr. / Black-tailed prairie dogs (Cynomys ludovicianus) are a species of management and conservation concern. Prairie dogs have lost both habitat and occupied area due to plague, which is caused by the bacterium Yersinia pestis, pest control, and habitat conversion to agricultural land. Our goals were to estimate survival rates and dispersal rates, and to compare methods for estimating abundance of black-tailed prairie dogs for both management and conservation. We trapped black-tailed prairie dogs at four small National Parks from April 2009 through August 2011. Prairie dogs were trapped and marked for two trapping sessions per year in order to estimate seasonal rates of apparent survival. Apparent survival rates were estimated using the package RMark in R to construct models for program MARK. We found estimates to vary according to field site, sex, year, and season (summer or winter). Possible reasons for the differences in survivorship among sites could be presence of disease, quality of forage, predation, or frequency of dispersal. Visual counts were also conducted each trapping session beginning in April of 2010 to estimate abundance. Mark-recapture, mark-resight, and visual counts were compared to determine which method would be the most effective for estimating abundance of prairie dogs. We found mark-resight to produce the most precise estimates of abundance. While it costs more money to conduct a mark-resight estimate than visual counts because of repeated sessions, they produced significantly different results from one another 75% of the time, which was especially apparent on sites that had some form of visual barriers such as tall vegetation and uneven ground. However, if further information is needed in terms of sex ratios, age ratios, or the exact number of prairie dogs, then mark-recapture is the only method that can be used. Land managers need to address the level of accuracy needed, topography, and vegetation height before choosing which sampling method is best for the prairie dog towns in question. Finally, we looked at rates of intercolony and intracolony dispersal by placing 149 VHF collars and 6 GPS collars on prairie dogs at three colonies. Intracolony dispersal was also monitored through visual observation and trapping records over the three years of the study. We found 23 intracolony and eight intercolony dispersal events. Combined, these three studies offer insight not only into monitoring of prairie dog populations but also potential influence by plague both within and among colonies of prairie dogs.

The Utah prairie dog (Cynomys parvidens) was listed by the U.S. Fish and Wildlife Service as an endangered species in 1973 because of range-wide population declines. The species was reclassified as threatened in 1984 because of population increases on private lands. Habitat fragmentation coupled with a lack of suitable habitat has impeded species recovery. Desired species habitat conditions include 0-8% shrub cover, 12-40% cool-season grass cover, and 1-10% perennial forb cover. Cool-season grasses are critical for Utah prairie dogs because of high spring energy requirements. Past research suggested that reducing shrub cover may increase cover of desired grasses and forbs. From 2008-2010, I evaluated the effects of high intensity fall sheep grazing and low application of herbicide (tebuthiuron) as tools to reduce shrub cover and enhance grass and forb cover on the Awapa Plateau Utah prairie dog recovery area in south-central Utah. I placed 1700 ewes in 4 ha stratified and randomly selected plots until >70% vegetation utilization was achieved. Five additional randomly-selected plots were treated with tebuthiuron at a rate of ~1.68 kg/ha. Percent cover of grass, forbs, and shrubs was recorded on treatments and paired control plots in June 2009 and 2010 to determine treatment vegetation responses. I also affixed 22 juvenile Utah prairie dogs with radio transmitters to determine if over-winter survival differed relative to treatment. Live shrub cover was lower on grazed plots in year 1 (P<0.001) and in year 2 (P=0.015). Dead shrub cover in grazed plots was higher in year 1 (P<0.001). Grazed plots exhibited increased forb cover from year 1 (P=0.104) to year 2 (P=0.008). Live shrub cover was lower in herbicide plots in year 2 (P=0.002). Dead shrub cover in herbicide plots was higher in year 2 (P=0.006). Tebuthiuron and grazed plots exhibited a reduction in shrub height (P=0.010, P=0.026, respectively). Tebuthiron plots exhibited less grass cover (P=0.034). Intensive sheep grazing and a low application of tebuthiuron reduced both shrub cover and vertical structure, but failed to increase the percent of grass cover when compared to the control plots. All plots exhibited reduced grass cover in 2010 in response to below normal precipitation. However, percent grass cover was higher on the grazed plots. It is possible that low inherent site productivity in combination with below normal average precipitation compromised treatment effects. Because of radio transmitter failure, I was not able to obtain survival data after hibernation. Prairie dog counts and weights did not differ by treatment type. If climate change reduces overall precipitation on the Awapa Plateau, recovery of the Utah prairie dog on this site will be problematic.

No description available.

One of the three largest systems of black-tailed prairie dog (BTPD) colonies is located in northwestern Chihuahua, Mexico. During the last two decades, the area occupied by these colonies has been highly reduced and fragmented. Previous studies suggested that agriculture, poisoning, cattle overgrazing and shrub encroachment could be the factors responsible for such declines. However, the severe drought occurring in the region between 1994 and 2004 has not been considered in this equation. Because these populations occur in arid regions at the southern edge of the species range, they could be especially sensitive to changes in plant productivity. Furthermore, fragmentation of colonies may accelerate population declines due to size and isolation effects. In this study, I analyzed species-habitat relationships at different spatial and temporal scales to understand the causes of recent declines of BTPDs in northwestern Chihuahua. The most severe loss of colony area and most local extinctions occurred between 1988 and 2000, but most likely before 1997. Extinction of colonies before 2000 mostly occurred at small and isolated colonies in low-productivity areas. The coincidence of greatest area decline with the occurrence of most intense drought suggests a prominent role of drought in the population collapse. Overall, patterns of BTPD occurrence and abundance in Chihuahua are greatly influenced by spatial and temporal variation in forage cover. Although BTPDs were more likely to occur in open areas with short vegetation, increased forage cover positively predicted occurrence. High levels of forage cover during the dry season were positively related with BTPD density, juvenile production and population rate of change, but forage cover during the preceding rainy season was a negative predictor of demographic indices. High plant productivity during humid periods seems to have negative impacts on BTPD populations, presumably because the rapid plant growth reduces visibility and predator detection by BTPDs. The most influential landscape variable was the effective isolation of colonies. Although increased isolation may reduce the probability of occurrence at a given site, highly isolated locations may support high population densities. Contrary to my original predictions, I did not detect significant impacts of human-related factors on BTPD distribution and abundance. / Ecology