10.5061/DRYAD.512M0
van der Plas, Fons
University of Bern
University of Groningen
Howison, Ruth A.
University of Groningen
Mpanza, Nokukhanya
University of Groningen
Cromsigt, Joris P. G. M.
Swedish University of Agricultural Sciences
Nelson Mandela University
Olff, Han
University of Groningen
Data from: Different-sized grazers have distinctive effects on plant
functional composition of an African savannah
Dryad
dataset
2017
plant–herbivore interactions
mesoherbivores
savannah
white rhino
bunch grass
grazing lawns
2017-01-11T00:00:00Z
2017-01-11T00:00:00Z
en
https://doi.org/10.1111/1365-2745.12549
27559049 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Grazing ungulates play a key role in many ecosystems worldwide and can
form diverse assemblages, such as in African savannahs. In many of these
ecosystems, present-day ungulate communities are impoverished subsets of
once diverse assemblages. While we know that excluding all ungulates from
grasslands can exert major effects on both the structure and composition
of the vegetation, how different individual ungulate species may have
contrasting effects on grassland communities remains poorly understood.
Here, we performed a long term “Russian doll” grazing exclosure experiment
in an African savannah to test for the effects of different size classes
of grazers on grassland structure and composition. At five sites, grazer
species of decreasing size class (ranging from white rhino to scrub hare)
were excluded using four fence types, to experimentally create different
realized grazer assemblages. The vegetation structure and the grass
functional community composition were characterized in six different years
over a 10 year period. Additionally, animal footprints were counted to
quantify the abundance of different ungulate species in each treatment. We
found that while vegetation height was mostly driven by total grazing
pressure of all species together, ungulate community composition best
explained the functional community composition of grasses. In the short
term, smaller ungulate species (‘mesoherbivores’) had strongest effects on
vegetation composition, by shifting communities towards dominance by
species with low specific leaf area and low nutritional value. In the long
term, large grazers had stronger but similar effects on the functional
composition of the system. Surprisingly, the largest ‘mega-herbivore’,
white rhinoceros, did not have strong effects on the vegetation structure
or composition. Synthesis. Our results support the idea that different
size classes of grazers have varying effects on the functional composition
of grassland plant communities. Therefore, the worldwide decline in the
diversity of ungulate species is expected to have (had) major impacts on
community composition and functioning of grassland ecosystems, even if
total grazing pressure has remained constant, e.g., due to replacement by
livestock.
long-term database on plant observationsDatabase with plant observations
for different sites (10 in total, but only those 5 with all fence types
were used in the associated paper) and five different fence types, for six
different years, collected in Hluhluwe-iMfolozi Park (HiP), South
Africa.SABRE_ZLTP_Exclosures.accdbgrass trait datain situ measured values
of SLA, leaf N content and canopy height. This data was originally
collected for the study van der Plas & Olff, 2014, Mesoherbivores
affect grasshopper communities in a megaherbivore-dominated South African
savannah, Oecologia 175: 639-649grass traits Fons.txtdaily rainfall
valuesrainfall data at the exclosure sites, collected on a daily basis.