DOI: 10.5061/dryad.95930
title: Data from: Migration in geographic and ecological space by a large herbivore

description: Partial migration, when only part of the population migrates seasonally
 while the other part remains resident on the shared range, is the most
 common form of migration in ungulates. Migration is often defined by
 spatial separation of seasonal ranges and consequently, classification of
 individuals as migrants or residents is usually only based on geographic
 criteria. However, the underlying mechanism for migration is hypothesized
 to be movement in response to spatiotemporal resource variability and
 thus, migrants are assumed to travel an ‘ecological distance’ or shift
 their realized ecological niches. While ecological and geographic
 distances should be related, their relationship may depend on landscape
 heterogeneity. Here, we tested the utility of ecological niche theory to
 both classify migratory individuals and to understand the underlying
 ecological factors for migratory behavior. We developed an integrative
 approach combining measures in geographic and ecological niche space and
 used this to classify and explain migratory behavior of 71 annual roe deer
 (Capreolus capreolus) movement trajectories in five European study areas.
 Firstly, to assess the utility of the ecological distance concept for
 classifying migratory behavior, we tested whether roe deer sought the same
 ecological conditions year-round or moved to different ecological
 conditions by measuring the annual ecological distance travelled and the
 seasonal niche overlap using multivariate statistics. Comparing methods to
 classify migrants and residents based on geographic and ecological niche
 space, we found that migratory roe deer switched between seasons both in
 geographic and in ecological dimensions. Secondly, we tested which
 seasonal ecological factors separated resident from migrant niches using
 discriminant analysis and which broad-scale determinants (e.g.,
 spatiotemporal forage variation and population density) predicted
 migration probability using generalized linear models. Our results
 indicated that factors describing forage and topographic variability
 discriminated seasonal migrant from resident niches. Determinants for
 predicting migration probability included the temporal variation
 (seasonality) and also the spatial variability of forage patches. Lastly,
 we also found suggestive evidence for a positive relationship between
 population density and migration probability. By applying the ecological
 niche concept to the study of partial migration in ungulates, our work
 underlines that partial migration is a form of behavioral plasticity.
description: Roe deer location
 dataThis dataset contains
 location data of roe deer collected with global positioning system (GPS)
 collars in five European study areas. The fields include: ‘animal_id’
 (unique individual identifier in the dataset), ‘year’ (year the GPS
 location was taken), ‘month’ (month the GPS location was taken), ‘day’
 (day the GPS location was taken), ‘lat’ and ‘long’ (roe deer locations
 expressed as latitude and longitude) and ‘sa’ (the study area id, which
 corresponds to the same study area acronyms used in the
 paper).RoedeerData_EM.csv