On this side of the fence: Functional responses to linear landscape features shape the home range of large herbivores

1. Understanding the consequences of global change for animal movement is
a major issue for conservation and management. In particular, habitat
fragmentation generates increased densities of linear landscape features
that can impede movements. 2. While the influence of these features on
animal movements has been intensively investigated, they may also play a
key role at broader spatial scales (e.g. the home range scale) as
resources, cover from predators/humans, corridors/barriers, or landmarks.
How space use respond to varying densities of linear features has been
mostly overlooked in large herbivores, in contrast to studies done on
predators. Focusing on large herbivores should provide additional insights
to understand how animals solve the trade-off between energy acquisition
and mortality risk. 3. Here, we investigated the role of anthropogenic
(roads and tracks) and natural (ridges, valley bottoms and forest edges)
linear features on home range features in five large herbivores. We
analysed an extensive GPS monitoring data base of 696 individuals across
nine populations, ranging from mountain areas mostly divided by natural
features to lowlands that were highly fragmented by anthropogenic
features. 4. Nearly all of the linear features studied were found at the
home range periphery, suggesting that large herbivores primarily use them
as landmarks to delimit their home range. In contrast, for mountain
species, ridges often occurred in the core range, probably related to
their functional role in terms of resources and refuge. When the density
of linear features was high, they no longer occurred predominantly at the
home range periphery, but instead were found across much of the home
range. We suggest that, in highly fragmented landscapes, large herbivores
are constrained by the costs of memorising the spatial location of key
features, and by the requirement for a minimum area to satisfy their vital
needs. 5. These patterns were mostly consistent in both males and females
and across species, suggesting that linear features have a preponderant
influence on how large herbivores perceive and use the landscape.