Water availability in temperate ecosystems – an emerging driver of large mammals activity and space-use in the era of global warming

Increasing temperatures and drought frequencies have caused significant water deficits and a rising water crisis
in many regions worldwide. Water scarcity has a negative impact on many aspects of human activity (e.g.,
agriculture, industry and energy production) and functioning of natural ecosystems (biodiversity loss, species
range shifts, more frequent fires and insect outbreaks). Water scarcity is also a challenge that needs to be
addressed in Europe, where droughts have become more frequent in recent years and their severity is predicted
to increase in the future. Importantly, the problem of drought and water scarcity is not only limited to southern
regions of Europe, but it also applies to Central and Eastern Europe. As a consequence, temperate mammals
are increasingly exposed to water shortage, which can negatively affect their reproductive performance and
survival. In addition, competition for limited water resources can lead to interspecific interactions which may
cause changes in trophic cascades. Therefore, understanding the influence of water availability on ecology and
behaviour of large mammals from temperate zone is crucial to understand the effect of on-going and future
climate change.
Studies linking water availability with different aspects of large mammal ecology and behaviour have been
conducted almost exclusively in arid and semi-arid ecosystems, where water availability has been one of the
most important factors affecting large mammal distribution, interspecific interactions and survival. Yet, little
is known about this relationship for mammals occurring in temperate ecosystems. In Central Europe, recent
summer droughts caused the highest water storage deficit in the history of the long-term climatology but the
consequences of these events for large mammals are largely unknown. Because the ability of large mammals
from temperate climates to adapt to prolonged water shortage may be limited, the impact of the drought can
be even greater than in mammals from arid ecosystems. Therefore, there is an urgent need to understand how
water availability influences large mammals in temperate ecosystems.
The main aim of the proposed project is to describe the ecological consequences of the water availability
for large mammals in temperate ecosystems. We plan to explore this problem by using data on the distribution
of large mammals in the Polish part of Białowieża Forest (BF; NE Poland), which were already collected in
previous projects (telemetry data), as well as by collecting new high-resolution data in the field (camera-trap
data). BF is an excellent area to study this problem because this ecosystem is inhabited by five ungulate species
(European bison, moose, red deer, roe deer and wild boar) and two species of large predators (wolf and lynx),
and water availability in this ecosystem has been highly variable in the last decade.
We expect that in temperate zone, space use of large mammals during growing season (May-September)
will reflect the spatio-temporal variation in water availability. We predict that during drier periods, large
herbivores will increase utilization of wet habitats, which provide both increased access to water bodies and
forage with increased moisture content. We also predict that during dry and hot periods, large mammals will
increase utilization of waterbodies. Additionally, we expect water use to be species-specific, with large-bodied
grazers being more water-dependent than small-bodied browsers. Furthermore, we expect that predation and
interspecific competition for access to water will cause spatial and temporal segregation of large mammals at
drinking sites. We predict that prey species will avoid predator either by using different water sites or by
switching visitation hours. Finally, we expect species-specific differences in the temporal patterns of utilization
of water resources among large herbivores. We predict that smaller species will escape competition with larger,
more dominant species by using water sites at different hours than the dominant species. Verification of
proposed predictions will provide new knowledge on the effect of water availability on the ecology and
behaviour of large mammals and initiate a broader discussion on the consequences of water deficit for large
mammals in temperate ecosystems.