DOI: 10.5061/dryad.6wwpzgmw7
title: LTREB: Yaha Tinda Elk Project

description: The Ya Ha Tinda Elk project is now amongst the longest running elk
 research project in the world.  Initiated in 2000, the Ya Ha
 Tinda elk project is the result of a collaboration between University of
 Alberta, University of Montana, Parks Canada, and Alberta Environment and
 Parks, Fish and Wildlife Division.  While early studies in the
 late 1970’s and early 1980’s lead by Dr. Luigi Morgantini laid the
 foundation for our latter studies (Morgantini and Hudson 1988), there was
 a ~ 20-year gap in active research on Alberta’s most important elk
 population.  Initiated at first because of questions regarding
 the changing migratory dynamics of the migratory Ya Ha Tinda elk
 population, the project has since evolved into North America’s longest
 running wild, free-ranging elk research projects focused on fundamental
 and applied research. The Ya Ha Tinda is one of Alberta’s most pristine
 montane rough fescue winter ranges and elk which provides the habitat
 foundation for one of Canada’s most iconic and largest
 populations.  The Ya Ha Tinda elk population is also a
 transboundary system, with annual elk migratory cycles that have spanned
 two provinces (elk have migrated into Yoho National Park, British
 Columbia), two land management regimes including Banff National Park,
 Provincial Forest Land Use Zones, and Provincial multiple use
 zones.  Ya Ha Tinda is also managed as a premier bull elk harvest
 area that provides much sought-after hunting opportunities to residents
 and guided hunters alike.  Meaning mountain prairie in the Stoney
 Sioux language, Ya Ha Tinda has long been important to First Nation
 communities for hunting and traditional land use practices.  And
 the region is also home to recovered populations of grizzly bears, wolves,
 and other large mammal predator-prey species, including for the first time
 in over a century – Plains bison. In this transboundary setting, our
 long-term research has contributed directly to enhancing interagency
 cooperation and management of this important elk population. Our long-term
 studies have documented dramatic changes in migratory behavior and
 population dynamics arising from this complex landscape of gradients in
 carnivore densities, habitat productivity, and differences in land
 management practices. Over the last 30-40 years migrant to resident ratios
 have substantially decreased from 12:1 (1977-1987, (Morgantini and Hudson
 1988)), 3:1 in the early 2000’s (Hebblewhite et al. 2006), to more
 recently a ratio closer to 1:1 (Berg 2019).  Early studies in the
 2000’s demonstrated that migratory elk moving west into BNP experienced
 much higher forage quality which translated to higher calf 8-month old
 weights and higher pregnancy rates (Hebblewhite et al. 2008). 
 Yet western migrants also experienced reduced predation risk from wolves,
 but higher risk from grizzly bear predation (Hebblewhite and Merrill 2007,
 MacAulay 2019). Resident elk remaining year-round near Ya Ha Tinda, in
 contrast, experienced lower forage quality, but, compensated for this by
 reducing predation risk by seeking out fine-scale predation risk refugia
 surrounding human development at the Ya Ha Tinda (Hebblewhite and Merrill
 2009, Robinson et al. 2010). Commensurate with these shifts in the
 migratory dynamics of this population have been correspondingly
 significant population shifts and changes (Hebblewhite et al. 2006,
 Killeen et al. 2015, Berg 2019).  In the last decade, a new
 migratory strategy has emerged with female elk now undertaking an eastward
 migration into Provincial multiple use lands in and adjacent to the 2001
 Dogrib fire (Killeen et al. 2015). Long-term research revealed individual
 elk are making density-dependent switches in migratory behavior, evidently
 to seek out these new beneficial areas (Eggeman et al. 2016). In 2013 –
 2017, we lead a neonate calf survival research component to understand
 spatial variation in calf survival (Berg 2019).  Calf survival
 and cow:calf ratios have indicated that calf survival of elk migrating
 east on to industrial forest experienced higher calf survival. In January
 2019, Jodi Berg defended her PhD thesis on elk calf survival, and her
 thesis details are provided in our publications section below. This new
 migratory behavior has seemingly stabilized the Ya Ha Tinda elk
 population, which has fluctuated between 400 – 600 elk now for almost a
 decade. Our long-term predator-prey research shows, however, that this
 stabilization is not likely a result of wolf or grizzly bear predation
 stabilizing the population at low density (Hebblewhite et al. 2018).
 Instead, our research suggests that migratory behavior itself may be
 providing escape from low densities (Hebblewhite et al. 2018).
description: We analyzed 18 years of
 demographic and migratory data from the Ya Ha Tinda elk population in and
 adjacent to Banff National Park (BNP), Alberta, Canada. The winter range
 is the Parks Canada-owned Ya Ha Tinda Ranch where ~100 - 180 horses are
 boarded during winter for use in the National Parks. The Ya Ha Tinda elk
 population has been studied since 1972 (Morgantini et al. 1988), with
 Global Positioning System (GPS) radiocollared individuals starting in
 2001. From 1972 the population size grew from 800 in the early 70’s,
 reached a peak of 2200 elk in the mid 1990’s, and then has declined and
 stabilized around 500 elk since 2010. The winter range of the Ya Ha Tinda
 elk population is a rough fescue (Fesctuca campestris) grassland which
 covers 20 km2. In winter, Chinooks (warm air and high winds) clear snow
 from the grassland acting as a refuge for ungulates. The summer range
 consists of three distinct areas used by 3 different migratory tactics, 1)
 residents who remain year-round on the rough fescue grassland, 2) eastern
 migrants which migrate to the eastern foothills that experience logging
 and oil and gas extraction, and 3) western migrants- migrate into BNP
 living in alpine or subalpine ecotypes (Fig. 1). Each summer range has
 different levels of forage quality and predation risk by human and
 non-human predators (Hebblewhite and Merrill 2009). This population is
 hunted in the provincial portions of their range and treaty First Nations
 harvest can occur year-round for males and females. For more details, see
 (Hebblewhite et al. 2006). <i>Aerial count data
 [YHT_MinimumCountWinterElkSurveys.csv]</i>— Elk count data were
 collected annually by Parks Canada or Alberta Environment and Parks
 Biologists on the winter range in January-March, based on helicopter (most
 commonly a Bell 206 Long Ranger) availability and ideal survey conditions
 (full snow cover). Aerial surveys were not conducted in 2015 and 2018.
 Because these surveys were not repeated within a year, nor were
 sightability parameters estimated, we assume that the counts from the
 aerial surveys are an index of the true population size but represent a
 minimum population count. To align our estimates of the aerial surveys
 with our population count data and ratio data which is also collected in
 February and Mark, we estimated our total population size and cow: calf
 ratios 2 months prior to the model anniversary on 1 June. <i>Calf: cow ratio data
 [YHT_CalfCowRatioData.csv]</i>— We conducted ground-based surveys
 during the months of February- March. During these surveys we collected
 sex and age ratio data of observed elk groups. We estimated the cow: calf
 ratio by summing the total number of observed calves divided by the total
 number of observed cows (Hurley et al. 2011). The calf to female variance
 was calculated following the methods of Cochran (1977). The error rate
 associated with determining yearling and adult females is very high and
 thus the denominator included both adult and yearling females.
 <i>Survival data
 [YHT_AdultFemaleSurvivalDataRaw.csv;
 YHT_AdultFemaleSurvivalRate.csv]</i>— We captured and radio-collared
 adult female elk in late winter (February-March) from 2001-2018. In the
 early years of the study (2001-2012), female captures were conducted using
 baited corral traps and aerial net-gunning. After 2013, all female elk
 were captured using ground-darting from horseback. Female elk were fitted
 with a Global Positioning System (GPS) and/or a Very High Frequency (VHF)
 collar to provide location and mortality data. All elk were captured and
 handled using techniques approved by the University of Montana IACUC
 (AUP-MH004-16). Trained personnel determined cause of death as soon as
 mortality of a collared elk was detected (on average within 5.2 days (SE=
 8.0), from Hebblewhite and Merrill (2011)) using consistent criteria (Alt
 and Eckert 2017). We used a modified Kaplan Meier- non-parametric survival
 model to estimate adult survival. Monthly survival was estimated using a
 Bayesian, generalized-linear mixed-effect model with a random effect for
 migratory tactic: year and a fixed effect for migratory tactic. These
 monthly survival estimates were multiplied to obtain a yearly survival
 estimate for each tactic<i>
 (YHT_AdultFemaleSurvivalRate.csv)</i>. The raw data provided has an
 indicator of the state of the animal indicating if the observation
 resulted in the elk being alive was alive (1) or dead (2-
 unknown/natural/other,3-wolf, 4 grizzly bear, 5 cougar, 6 human
 caused). <i>Calf survival data
 [YHT_CowCalfObsData.csv]:</i> Calf survival was estimated using
 cow-calf resight of marked female elk. Individual female elk were observed
 multiple times (x̄=3) between 1 July and 1 April with the presence or
 absence of a calf being recorded for each occasion. Monthly survival rates
 were estimated using a modified Cormack-Jolly-Seber model where all
 observed individuals were assumed to have a calf at the first occasion. If
 a calf was seen with a marked female it was recorded as alive and if it
 was not observed with a marked female it was recorded as
 unobserved.