DOI: 10.5061/dryad.18931zd68
title: Elk resource selection and indicator species analysis

description: Resource selection by animals varies depending on spatial and temporal
 context, thus it is important to account for these factors when conducting
 studies that examine this behavior relative to the availability and
 distribution of resources.  Many resource selection studies
 combine fine-scale animal location data obtained using Global Positioning
 System (GPS) technology and coarse-scale, remotely sensed, spatial layers.
 Fewer studies combine fine-scale animal location data with vegetation data
 collected in the field, which can identify important fine-scale drivers of
 resource selection. Understanding fine-scale resource selection of
 ungulates inhabiting regions dominated by closed-canopy forests may
 provide important information regarding management actions that improve
 habitat quality. From April 2021–August 2022, we conducted vegetation
 surveys at locations (n = 1,294) used by 39 GPS-collared elk (Cervus
 canadensis) and at paired random locations (n = 2,509) available to elk.
 We used conditional logistic regressions to compare seasonal (spring,
 summer, fall, winter) vegetation characteristics between used and
 available locations. We also conducted a species indicator analysis to
 compare plant species found at used and available locations during peak
 foraging periods (dawn/dusk). Regardless of season, the probability of use
 by elk increased as tree basal area (m2/ha) decreased, and the presence of
 herbaceous plants increased. Clovers (Trifolium spp.)
 were indicators of locations used by elk during primary foraging
 periods regardless of season. Other plants that were indicators of
 locations used by elk during at least one season included purple-crown
 vetch (Securigera varia), bird’s foot-trefoil (Lotus corniculatus), and
 black medick (Medicago lupulina). This research highlights the importance
 of managed openings, ecotones, and other communities characterized by
 reduced tree cover and increased herbaceous plants to meet the foraging
 needs of elk in landscapes dominated by closed-canopy forests. Creating
 and maintaining managed herbaceous openings and restoring open-forest
 communities will likely facilitate elk population growth and expansion.
description: # Elk resource selection and indicator species analysis
 [https://doi.org/10.5061/dryad.18931zd68](https://doi.org/10.5061/dryad.18931zd68) ## Description of the data and file structure We completed 3803 vegetation surveys at 1294 used and 2509 available locations from 39 individuals (23 females; 16 males) across four seasons from April 2021 – August 2022. Vegetation surveys included collecting information on basal area and herbaceous and woody plant species from five 1m^2 quadrants at each sampling location. Elk resource selection at elk used and available locations were analyzed with conditional logistic regressions for each season. Additionally, to determine indicator species of herbaceous plants and woody stems &lt;0.5 m found in 1 m^2 quadrants at locations used by elk and areas available but unused during foraging periods (hereafter referred to as site groups), the diagnostic index IndVal from package indicspecies (Dufrene and Legendre 2009) was calculated to assess species association between site groups. ### Files and variables #### File: Fall\_RSF.csv, Spring\_RSF.csv, Summer\_RSF.csv, Winter\_RSF.csv **Description:**  ##### Variables * animal_ID: individual elk ID * pointvegid: name of sampling location  * pointstatus: identifying if sampling location is a used (1) or available (0) sampling location. * season: season vegetation survey was conducted in * NEAR_DIST: distance to forest-open ecotone (m) * clid: ID of paired used and available sampling locations  * Forb: Presence of forbs (1= present, 0 = absent) * Graminoid: Presence of graminoids (1= present, 0 = absent) * sex: male or female elk * basalarea_m2_ha: basal area per m2/ha * log_mast: logged term for basal area of mast producing trees (m2/ha) * NEAR_scale: Scaled variable distance to forest-open ecotone * log_mast_scale: Scaled variable "log_mast" * label: used or available locations * log_total_ba: logged variable- total basal area (m2/ha) * log_totalbascale: logged variable NEAR_scale * CON_DIST: Distance to mixed/evergreen forest ecotone (m) * CON_DISTscale: scaled variable "CON_DIST" * log_scale: logged variable "log_total_ba" #### File: spring\_indicator.csv, summer\_indicator.csv, fall\_indicator.csv, winter\_indicator.csv **Description:**  ##### Variables * pointvegid: name of sampling location  * species: species of plant found in quadrant * Family: family of plant found in quadrant * Genus: genus of plant found in quadrant * Species_epithet:species epithet * type:catogorizing plants into forb, graminoid, woody vegetation variables * season:season data was collected in * Center: Plants found in center quadrant * N: Plants found in north quadrant * E: Plants found in east quadrant * S: Plants found in south quadrant * W: Plants found in west quadrant * pointstatus: used or available location * sex: male or female elk * behavior: foraging period * grouped_sp: plants grouped into family, genus, or species * total: mean abundance of plants in quadrant ## Version changes  **Oct-2024:** Corrected a mislabel in pointvegID/sex for elk 21033 and 20252 in summer_rsf.csv ## Code/software R 4.1.1 was used for the analysis of this data.  Detailed scripts are included as R Markdown files.