10.5061/DRYAD.44J0ZPCHR
Koch, Franziska
0000-0003-3019-323X
University of Hohenheim
Tietjen, Britta
Freie Universität Berlin
Tielbörger, Katja
University of Tübingen
Allhoff, Korinna
University of Hohenheim
Livestock management promotes bush encroachment in savanna systems by
altering plant-herbivore feedback
Dryad
dataset
2022
Alternative stable states
shrub encroachment
positive feedback
ecosystem stability
tipping point
FOS: Biological sciences
Federal Ministry of Education and Research
https://ror.org/04pz7b180
01LC1821B
2022-10-05T00:00:00Z
2022-10-05T00:00:00Z
en
https://doi.org/10.5281/zenodo.7144740
3368 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
This repository contains all code to reproduce the analysis in Koch et al.
2022 "Livestock management promotes bush encroachment in savanna
systems by altering plant-herbivore feedback". We use a set of
coupled differential equations to describe competition between shrubs and
grasses, as well as plant biomass consumption via grazing and browsing.
Grazers were assumed to receive a certain level of care from farmers, so
that grazer densities emerge dynamically from the combined effect of
vegetation abundance and farmersupport. Our main goal was to understand
how critical transitions from grass-dominated to shrub-dominated system
states were affected by the dynamic role of grazing. Our results show that
bistability emerges for intermediate levels of farmer support due to
positive feedback that arises from competition between shrubs and grasses
and from herbivory. We furthermore demonstrate that disturbances, such as
drought events, trigger abrupt transitions from the grass dominated to the
shrub dominated state and that the system becomes more susceptible to
disturbances with increasing farmer support.
We used numerical simulations to analyse system dynamics under different
livestock management and disturbance regimes. Then, we quantified all
self-reinforcing and self-dampening feedback loops to determine their
relative importance in shaping system (in)stability. The whole analysis
was performed in python. For details, see the Methods section of the
corresponding paper.