Model-based Impact Analysis of Climate Change and Land-use
Intensification on Trophic Networks
Abstract
Global change impacts the structure of communities within trophic food
webs well before a decline in biodiversity can be measured for instance
by species numbers. While land use change is the most important direct
driver of terrestrial biodiversity loss, its impact in combination with
climate change is less well understood. We investigate the combined
effects of climate change (temperature, precipitation) and land-use
intensification on terrestrial trophic networks, with a process-based
general mechanistic ecosystem model (‘MadingleyR’) that simulates
ecosystem dynamics for trait-based functional groups of species (i.e.,
ectothermic, and endothermic herbivores, carnivores, and omnivores) for
different regions such as India and Europe. Resulting patterns are
widely consistent across selected regions. The greatest effect of
climate change and land use is observed for carnivores. Both, land use
intensification and climate change, cause a substantial decrease in the
biomass of different functional groups, while some functional groups
(generalists, omnivores), partially benefit. Large endotherms are
negatively affected by land use intensification, while ectotherms are
under pressure from rising temperatures in a changing climate. Arid and
tropical regions show a higher response to climate change, with losses
of up to -3.4% and -1.9% in total biomass, while areas with low net
primary productivity show the most negative response to land use
intensification (up to -6.7% in total biomass). Our results suggest
that land use intensification (a) has a significant impact on larger
organisms and predators, leading to a major restructuring of global food
webs, (b) Ectotherms are particularly vulnerable to rising temperatures,
and (c) regions in tropical or arid climates experience significant
changes in their community composition and will be threatened in their
biodiversity.