Causes and Consequences of Woody Plant Encroachment: Will Meadow Edge Burns Alter Elk Habitat Selection?
Areas once dominated by grassland have experienced increases in establishment rates of woody species largely due to fire suppression. The removal of fine fuels by herbivores can prolong fire return intervals and decrease blaze intensity, as well as provide openings in the grassland canopy for shrub or tree establishment. These disturbances are frequently cited as drivers of community change and woody plant encroachment in grasslands. Within the montane ecoregion, fescue provides nutritional winter forage for the Ya Ha Tinda elk herd, one of the largest elk populations in Alberta. The Ya Ha Tinda has not burned since 1936 (historical frequency being less than 50 years), and likely invasion of shrubs and trees has likely shifted the herbaceous species composition away from a fescue grassland community (Willoughby 2001, Bailey and Wroe 1974). Large scale changes in plant communities can be detected using remote sensing, and are well complimented by ground sampling (Sankey et al. 2006). Using a series of aerial photos integrated into a GIS, I wish to determine a) if the amount of grassland has declined over time, b) if this rate of decline is constant throughout the Red Deer River drainage, and c) what factors influence grassland conversion at the local (eg-aspect, elevation) or more global (fire, grazing, climate) level between areas in the Red Deer River drainage over time. I will also examine shifts in understory species composition in areas experiencing encroachment. As low grazing intensities may result in lower rates of encroachment , will assess elk habitat selection in response to burning along the Ya Ha Tinda meadow edge. It is possible that burning the forest adjacent to the Ya Ha Tinda will attract elk to high quality herbaceous matter. I will determine whether this management technique is capable of temporarily reducing grazing pressure on the fescue grassland during the critical spring growth period.
M.Sc. Student: Lindsay Glines
Project Completion: 2010
Funding: University of Alberta, ACA
Wolf Summer Predation Dynamics
This project will investigate summer kill rates and composition of wolves (Canis lupus) in west-central Alberta. The vast majority of studies on large carnivore predation, including kill rates and composition, have been based on winter studies. Because large carnivores that rely on ungulates as prey often show a preference for juveniles, kill rates may be both higher and more variable during the summer season than during the rest of the year which may lead to underestimates of the total annual predation rate. This study will be the first to present detailed empirical data on kill rates and prey selection by wolves in a multi-prey system during the summer (May-September) as obtained by applying modern Globa Positioning System collar techniques on individual wolves in North America.
M.Sc. Student: Peter Knamiller
Project Completion: 2010
Funding: University of Alberta, ACA, SCI-NAC, APOS, Minister’s Special License Program, The Wild Sheep Foundation, FNAWS–Alberta Chapter, FNAWS–Eastern Chapter, Alberta SRD, Alberta Fish and Game Association, ACCRU, Alberta Trapper’s Association
Border Deer Study
The Border Deer Study (BDS) is a multi-year project with the goal of linking scientific knowledge with wildlife management, particularly in the realm of chronic wasting disease (CWD). This study will help identify the potential epidemiological risk of CWD entering and spreading into Alberta along portions of the Saskatchewan border. The immediate focus of this research is on deer herds in wildlife management unit (WMU) 234 where we believe the disease is present in local deer that move seasonally from summer ranges in Saskatchewan to winter concentrations in Alberta. Research in this area will complement a similar study underway in the Saskatchewan Landing area of Saskatchewan.
The short-term objectives of the BDS are to define white-tailed ( Odocoileus virginianus ) and mule ( O. hemionus ) deer population units at risk, quantify their seasonal movement patterns, and examine potential exchange rates among populations. Long-term objectives include modeling potential disease spread and evaluating alternative population management actions that will prevent or reduce the rate of spread of CWD in or into Alberta.
Deer Movement and Disease Spread
The primary goal of my research is to identify potential corridors for CWD spread into Alberta from Saskatchewan . To do this I will create a model that mimics deer dispersal. I will identify those locations from the GPS collar data that reflect dispersal like behaviour. I will use these dispersal locations to create a step selection function that can evaluate the relative likelihood of a deer using one route for dispersal versus other alternatives. By running iterations that imitate deer dispersal I can find potential corridors for CWD spread.
A secondary goal is to compare and contrast deer habitat selection within and outside of a home range. I can do this because by creating the step selection function I will have an understanding of what environmental factors are important to deer outside of their home ranges. I have already created a resource selection function as part of a previous project that models within home range deer habitat selection in the same area. When I compare these two models I should gain a better understanding of differences in deer habitat selection within and outside of a home range.
M.Sc. Student: Barry Norbert
Project Completion: 2011
Funding: Alberta PRION Institute, University of Alberta, Alberta SRD, Alberta AFRD, Saskatchewan Environment, University of Saskatchewan, APOS, ACA, AIF, ACCRU
Epidemiological Modelling of Chronic Wasting Disease (CWD)
CWD studies have focused more on what factors influence spatial patterns of CWD prevalence than its temporal emergence. With my collaborators, we use Saskatchewan (SK) hunter-harvest data from south-western SK to identify factors associated with early spatio-temporal spread, and use these factors to build a model that predicts early disease spread in recently infected areas across the border in Alberta (AB). We apply a new strategy using time-to-event modelling, similar to that used in survival analysis, where the Cox proportional hazard ( CPH ) forms the basis of our model. Our objective was to predict the probability of harvesting at least one CWD-positive deer in a spatial unit (cell), at a given point in time (year), based on: (1) previous year’s known disease distribution among cells, (2) current (and previous) year’s demographic characteristics of harvest in a cell, (3) deer demographic and habitat factors of a cell, and (4) current year’s sampling intensity (number harvested deer tested for CWD) in a cell. This work has implications for future disease spread in SK and AB with regard to guiding additional disease surveillance in these areas.
My second research objective is to adapt a spatially explicit, individual-based model that has been used for investigating raccoon rabies spread (e.g. see Rees et al. 2008a) and use this model to test hypotheses about how deer ecology and CWD control strategies will affect disease spread. The flexible structure of the model enables testing of factors hypothesised to affect animal movements and gene flow, and hence, the flow of infectious disease spread.
Post-doctoral fellow: Erin Rees
Project Completion: 2009
Funding: University of Alberta, Alberta PRION Institute
Landscape Structure and Deer Distribution: Implications for Contact Rates and CWD
Chronic wasting disease (CWD) is a fatal, contagious prion disease of cervids that has been detected in white-tailed and mule deer in east-central Alberta. I am studying factors affecting contact rates between white-tailed and mule deer in Alberta, which are a primary driver of disease transmission. Contact rates are believed to be influenced by deer density, but landscape features that concentrate deer into specific patches may also play a role. My work addresses two aspects of this problem: 1) I am evaluating alternative aerial survey designs that will maximize precision in deer population estimates at large scales; and 2) Identifying patterns of deer distribution at scales relevant to CWD transmission, and determining how they are affected by overall density as well as landscape features.
M.Sc. Students: Tom Habib
Project Completion: 2009
Funding: Alberta PRION Institute, University of Alberta, Alberta SRD, Alberta AFRD, Saskatchewan Environment, University of Saskatchewan, APOS, ACA, AIF, ACCRU
Implications of Spatial Heterogeneity on Wolf Attach Rates, Hunting Path Placement and Kill Location
Traditional predator-prey models assume that interactions between species occur in fine-grained, homogeneous settings. However, in natural systems, communities exist in spatially heterogeneous environments. Previous work has shown that predator responses to landscape and prey heterogeneity can alter the predicted attack rate-prey density relationship and create variable predation rates across space. This can vastly alter predator-prey dynamics, often resulting in increased persistence of communities.
The first objective of my Master’s thesis is to identify how spatial heterogeneity of landscape and prey influence the attack rates of wolves (Canis lupus) in a natural setting. Using GPS-collared wolves and time-to-event models, we will evaluate how exposure to a variety of characteristics along discrete hunt paths influence the attack rates on small-(deer) and large-bodied (elk, moose, horse) prey. Secondly, we will examine the role of landscape and prey characteristics at scales reflecting two processes of predation: where wolves select to hunt and where wolves kill within discrete hunting paths. My thesis work will identify whether characteristics that influence attack rates of wolves translate to increased abundance of kills across the landscape. We will further identify certain landscape and prey characteristics that influence attack rates, hunting path placement, and the ability to kill within hunt paths. Lastly, we will provide insight into mechanisms behind deviations from expected attack rate-prey density relationships and variability surrounding functional response curves.
M.S.c. Student: Heather McPhee
Project Completion: 2009
Funding: University of Alberta, ACA
Spatial Distribution and Anti-predator Behaviour of Migrant and Resident Elk on the Ya Ha Tinda Winter Range
This project will be comparing the spatial distribution, and anti-predator behaviour of the migrant and resident portions of a partially migratory elk (Cervus elaphus) herd on the Ya Ha Tinda (YHT) winter range in AB, Canada. Over the past 30 years the migratory portion of this herd has been declining with an increasing proportion of the population remaining on the YHT winter range for the entire year. The main goal of this project is to determine the mechanism driving the shift in the migrant to resident ratio within this herd. More specifically, this study will determine if migrant and resident elk (1) are spatially segregated on the YHT winter range and exposed to different levels of predation risk and forage quality, and (2) exhibit different strategies for trading off foraging and predator avoidance.
M.S.c. Student: Barry Robinson
Project Completion: 2009
Funding: University of Alberta, NSERC, Alberta Sport & Rec
A Behavioural Approach to Modeling the Trade-off between Risk and Reward: Elk Use of Cutblocks in Alberta
Forest ecosystems have historically undergone secondary succession due to natural disturbances such as fires. Recently the forestry industry and the creation of forestry harvest units (hereafter cutblocks) have surpassed fire as the major disturbance on the landscape in the central east slopes of Alberta. Cutblocks result in a reorganization of herbaceous and shrub species composition and abundance. The succession of ungulate forage abundance and composition, in particular, is strongly influenced by the age of the cutblock (time since felling) providing valuable foraging opportunities for resident elk. The foraging opportunities afforded by the creation of cutblocks vary in time and space creating a heterogeneous landscape within which elk forage. Here I quantify the successional trends in ungulate forage (both abundance and quality) in relation to management practices (site preparation and patch retention) for cutblocks located in the central east slopes of Alberta.
Ph.D. Student: Darcy Visscher
Project Completion : 2009
Funding: University of Alberta, NSERC Industrial
Woody Plant Encroachment Into Grasslands Within The Red Deer River Drainage, Alberta
grasslands play a key role in supporting wintering elk in the Rocky Mountains of Alberta. To document change in grassland extent and patch sizes. I analyzed repeat aerial photography at 4 sites in the upper Red Deer River (RDR) drainage between 1952 and 2003. Grassland extent declined 47+12% and coniferous forest increased 39+10%. The rate of grassland loss differed between sites (West Lakes (WL) > Tyrrell flats (TY) ~ Scotch camp (SC)); Ya Ha Tinda (YHT) increased slightly due to shrub mowing. Grassland patch size increased on average, but decreased in WL as larger patches fragmented. From 100-m transects along grassland-shrub-forest ecotones, I found differences in herbaceous biomass and richness between cover types but site specific changes with distance to woody cover were variable. Therefore, the forage base within the upper RDR drainage
M.Sc. Student:Lindsay Glines
Project Completion: 2012
Funding: University of Alberta, ACA, Parks Canada, NSERC
Seasonal Wolf Predation in a Multi-Prey System in West-Central Alberta
As reintroduced and recolonizing wolf populations expand across North America, they have the potential to reduce ungulate populations and alter prey community structure by influencing adult mortality and recruitment rates. Estimating annual wolf kill rates and composition is important for assessing the impact of wolves on their prey and managing wolf-ungulate dynamics. To date most studies have focused on kill rates of wolves in winter or single-ungulate dominated systems. I explored intra- and inter-seasonal variations in kill rates and prey composition of wolves in a multi-prey ungulate population. I used a combination of high intensity GPS tracking of wolves to locate wolf-killed, adult prey and auxiliary scat analysis to estimate neonate prey killed. I found wolves in summer selected for neonate prey of all species with deer comprising the greatest proportion of both adult and neonate prey. Consequently, summer kill rates (0.21 ungulates/ adult wolf/day) were among the highest (~1.5-2.5 times) reported in the literature on summer wolf predation and were 2.5 times higher than winter rates (0.08+0.02),when wolves killed a greater diversity of predominately adult prey. Average summer biomass consumption rates (4.22+0.36 kg/adult equivalent wolf/day) were lower than in winter (7.93+4.08), when wolves were less food limited due to reduced pack size likely resulting from high wolf harvest rates, this was reflected in their seasonal body masses. Seasonal differences in kill rates between summer and winter would have lead to significant underestimates (~29%) of annual kill rates when based on winter information only.
M.Sc. Student: Peter Knamiller
Project Completion: 2011
Funding: University of Alberta, ACA, SCI-NAC, APOS, Minister’s Special License Program, The Wild Sheep Foundation, FNAWS–Alberta Chapter, FNAWS–Eastern Chapter, Alberta SRD, Alberta Fish and Game Association, ACCRU, Alberta Trapper’s Association
Ecology and Management of White-tailed Deer and Mule Deer of East-Central Alberta in Relation to Chronic Wasting Disease
Chronic wasting disease (CWD) is a fatal pathogen affecting white-tailed and mule deer in east-central Alberta, and I addressed two current limitations of CWD management. First, to improve precision and accuracy of density estimates obtained from aerial surveys, I evaluated alternative survey designs and developed a model to correct for undetected deer due to low snow cover, small group sizes, and deer inactivity. Surveys stratified by resource selection functions showed the greatest improvement in precision compared to currently employed designs. Second, I addressed how density and landscape features affect contact rates among deer, a major component of CWD transmission. Contact rates increased as a saturating function of density, and were highest in regions where deer habitat was limited. My results will allow managers to better plan and evaluate management actions such as herd reductions, and underscore the need for developing spatially-explicit models to understand CWD spread in heterogeneous environments.
M.Sc. Students: Tom Habib
Project Completion: 2010
Funding: Alberta PRION Institute, University of Alberta, Alberta SRD, Alberta AFRD, Saskatchewan Environment, University of Saskatchewan, APOS, ACA, AIF, ACCRU
Targeting The Detection Of Chronic Wasting Disease Using The Hunter Harvestduring Early Phases Of An Outbreak In Saskatchewan, Canada
Abstract: Chronic wasting disease (CWD) is a fatal disease of North American cervids that was first detected in a wild, hunter-shot deer in Saskatchewan along the border with Alberta in Canada in 2000.Spatially explicit models for assessing factors affecting disease detection are needed to guide surveillance and control programs. Spatio-temporal patterns in CWD prevalence can be complicated by variation in individual infection probability and sampling biases. We assessed hunter harvest data of mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) during the early phases of an outbreak in Saskatchewan (i.e., 2002 to 2007) for targeting the detection of CWD by defining (1) where to look, and (2) how much effort to use. First, we accounted for known demographic heterogeneities in infection to model the probability, PE, that a harvested deer was infected with CWD given characteristics of the harvest location. Second, in areas where infected deer were harvested we modelled the probability, PD, of the hunter harvest re-detecting CWD within sample units of varying size (9-54 km2) given the demographics of harvested deer and time since first detection in the study area. Heterogeneities in host infection were consistent with those reported elsewhere: mule deer 3.7 times > white-tailed deer, males 1.8 times > females, and quadratically related to age in both sexes. PE increased with number of years since the first detection in our study area (2002) and proximity to known disease sources, and also varied with distance to the South Saskatchewan River and small creek drainages, terrain ruggedness, and extent of agriculture lands within a 3 km radius of the harvest. The majority (75%) of new CWD-positive deer from our sample were found within 20 km of infected deer harvested in the previous year, while approximately 10% were greater than 40 km. PD modelled at 18 km2 was best supported, but for all scales, PD depended on the number of harvested deer and time since the first infected deer was harvested. Within an 18 km2 sampling unit, there was an 80% probability of detecting a CWD-positive deer with 16 harvested deer five years after the initial infected harvest. Identifying where and how much to sample to detect CWD can improve targeted surveillance programs early in the outbreak of the disease when based on hunter harvest.
Post-doctoral fellow: Dr. Erin Rees
Project Completion: 2009
Funding: University of Alberta, Alberta PRION Institute
M.S.c. Student: Heather McPhee
Project Completion: 2009
Funding: University of Alberta, ACA
Foraging-Predator Avoidance Trade-Offs Made By Migrant And Resident Elk On Their Sympatric Winter Range
Migratory behaviour of the Ya Ha Tinda (YHT) elk population is diminishing while the number of residents remaining on the YHT winter range year-round is increasing. Previous research addressing the fitness consequences of each migratory strategy assumed there was no advantage to either segment when they shared the YHT winter range. In testing this assumption, I found no spatial segregation of migrant and resident home-ranges during winter. Both groups were exposed to similar forage resources and residents were exposed to higher night-time, but not day-time predation risk. Residents were better than migrants at reducing the foraging costs of vigilance and increased vigilance in areas of high wolf predation risk, but not near human activity because of habituation. Migrants were not habituated to humans and exhibited more constant vigilance regardless of spatial variations in risk. My results do not support the previous assumption. Instead, I found residents may be at an advantage on the winter range while forage is abundant and no snow is present.
M.Sc. Student: Barry Robinson
Project Completion: 2009
Funding: University of Alberta, NSERC, Alberta Sport & Rec
A Behavioural Approach to Modeling the Trade-off between Risk and Reward: Elk Use of Cutblocks in Alberta
Forest ecosystems have historically undergone secondary succession due to natural disturbances such as fires. Recently the forestry industry and the creation of forestry harvest units (hereafter cutblocks) have surpassed fire as the major disturbance on the landscape in the central east slopes of Alberta. Cutblocks result in a reorganization of herbaceous and shrub species composition and abundance. The succession of ungulate forage abundance and composition, in particular, is strongly influenced by the age of the cutblock (time since felling) providing valuable foraging opportunities for resident elk. The foraging opportunities afforded by the creation of cutblocks vary in time and space creating a heterogeneous landscape within which elk forage. Here I quantify the successional trends in ungulate forage (both abundance and quality) in relation to management practices (site preparation and patch retention) for cutblocks located in the central east slopes of Alberta.
Ph.D. Student: Darcy Visscher
Project Completion : 2010
Funding: University of Alberta, NSERC Industrial
Estimating Winter Carrying Capacity for Bison in Wood Buffalo National Park
Bison (bison bison) in the Peace-Athabasca Delta (PAD) of Wood Buffalo National Park have been fewer than the neighbouring Hay Camp since the late 1990s despite being greater in the 1970-80s. I compared the winter nutritional carrying capacity (K) of the PAD to the Hay Camp, assuming varying snow depth and forage preferences, to determine whether K was restricting in the PAD. I sampled plant cover and biomass to estimate forage availability and quality within five vegetation types, and estimated K for the extent of these types. The PAD had more biomass of preferred species, Carex atherodesand Calamagrostis spp., than the Hay Camp, resulting in 4 to 12 times the K of the Hay Camp. I simulated the effect of non-native plants on K assuming a 65% average reduction in preferred forage. Non-natives were more widespread and abundant in the PAD, but did not reduce K below that of Hay Camp.
Ph.D. Student: Stephan Hamilton
Project Completion :
Funding: University of Alberta, NSERC Industrial