DOI: 10.5061/dryad.80gb5mknj
title: Individual variation creates diverse migratory portfolios in native populations of a mountain ungulate

description: Ecological theory and empirical studies have demonstrated population‐level
 demographic benefits resulting from a diversity of migratory behaviors
 with important implications for ecology, conservation, and evolution of
 migratory organisms. Nevertheless, evaluation of migratory portfolios
 (i.e., the variation in migratory behaviors across space and time among
 individuals within populations) has received relatively little attention
 in migratory ungulates, where research has focused largely on the
 dichotomous behaviors (e.g., resident and migrant) of partially migratory
 populations. Using GPS data from 361 female bighorn sheep (Ovis
 canadensis) across 17 (restored = 4,
 augmented = 6, native = 7) populations
 in Montana and Wyoming, USA, we: 1) characterized migratory portfolios
 based on behavioral and spatial migratory characteristics, and 2)
 evaluated the relative influence of landscape attributes and management
 histories on migratory diversity. Native populations, which had been
 extant on the landscape for many generations, had more diverse migratory
 portfolios, higher behavioral switching rates, reduced seasonal range
 fidelity, and broad dispersion of individuals across summer and winter
 ranges. In contrast, restored populations with an abbreviated history on
 the landscape were largely non‐migratory with a narrow portfolio of
 migratory behaviors, less behavioral switching, higher fidelity to
 seasonal ranges, and less dispersion on summer and winter ranges.
 Augmented populations were more variable and contained characteristics of
 both native and restored populations. Differences in migratory diversity
 among populations were associated with management histories (e.g.,
 restored, augmented, or native). Landscape characteristics such as the
 duration and regularity of green‐up, human landscape alterations,
 topography, and snow gradients were not strongly associated with migratory
 diversity. We suggest a two‐pronged approach to restoring migratory
 portfolios in ungulates that first develops behavior‐specific habitat
 models and then places individuals with known migratory behaviors into
 unoccupied areas in an effort to bolster migratory portfolios in restored
 populations, potentially with synergistic benefits associated with
 variation among individuals and resulting portfolio effects. Management
 efforts to restore diverse migratory portfolios may increase the
 abundance, resilience, and long‐term viability of ungulate populations.
description: Elevation and geographic distances between individuals core
 seasonal ranges These data represent the elevational
 and geographic distances between individual core seasonal ranges of
 bighorn sheep from 17 populations across MT and WY. The IndID field is an
 individual ID, which has a different format in each population. The State
 field denotes the state (MT, WY) where the population was located. The
 population name is shown in the HuntUnit field. Note, populations have
 been aggregated as described in Appendix S1. Origin denotes the restored,
 augmented, or native classification as described in the methods section of
 the paper’s main text. The elevational difference between individual
 seasonal range centroids (in meters) is shown in the EleDistM column. The
 geographic distance between individual seasonal range centroids is shown
 in the GeoDistKM column.