Apex predators perform important functions that regulate ecosystems
worldwide. However, little is known about how ecosystem regulation by
predators is influenced by human activities. In particular, how important
are top-down effects of predators relative to direct and indirect
human-mediated bottom-up and top-down processes? Combining data on
species' occurrence from camera traps and hunting records, we aimed
to quantify the relative effects of top-down and bottom-up processes in
shaping predator and prey distributions in a human-dominated landscape in
Transylvania, Romania. By global standards this system is diverse,
including apex predators (brown bear and wolf), mesopredators (red fox)
and large herbivores (roe and red deer). Humans and free-ranging dogs
represent additional predators in the system. Using structural equation
modelling, we found that apex predators suppress lower trophic levels,
especially herbivores. However, direct and indirect top-down effects of
humans affected the ecosystem more strongly, influencing species at all
trophic levels. Our study highlights the need to explicitly embed humans
and their influences within trophic cascade theory. This will greatly
expand our understanding of species interactions in human-modified
landscapes, which compose the majority of the Earth's terrestrial
surface.
Dorresteijn et
al_Proceedings B_2015_raw data tableRaw data file used for
the structural equation model in the publication.
| Datum zugänglich gemacht | 17.08.2015 |
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| Verlag | ZENODO |
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| Datum der Datenproduktion | 17.08.2015 |
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