Data from: Quantification of population sizes of large herbivores and their long-term functional role in ecosystems using dung fungal spores

The relationship between large herbivore numbers and landscape cover over
time is poorly understood. There are two schools of thought: one views
large herbivores as relatively passive elements upon the landscape and the
other as ecosystem engineers driving vegetation succession. The latter
relationship has been used as an argument to support reintroductions of
large herbivores onto many landscapes in order to increase vegetation
heterogeneity and biodiversity through local-scale disturbance regimes.
Most of the research examining the relationship between large herbivores
and their impact on landscapes has used extant studies. An alternative
approach is to estimate the impact of variations in herbivore populations
through time using fossil dung fungal spores and pollen in sedimentary
sequences. However, to date, there has been little quantification of
fossil dung fungal spore records and their relationship to herbivore
numbers, leaving this method open to varied interpretations. In this
study, we developed further the dung fungal spore method and determined
the relationship between spore abundance in sediments (number cm−2 year−1)
and herbivore biomass densities (kg ha−1). To establish this relationship,
we used the following: (i) the abundance of Sporormiella spp., Sordaria
spp. and Podospora spp. spores in modern sediments from ponds and (ii)
weekly counts of contemporary wildlife over a period of 5 years from the
rewilded site, Oostvaardersplassen, in the Netherlands. Results from this
study demonstrate that there is a highly significant relationship between
spore abundance and local biomass densities of herbivores that can be used
in the calibration of fossil records. Mammal biomass density (comprising
Konik horses, Heck cattle and red deer) predicts in a highly significant
way the abundance of all dung fungal spores amalgamated together. This
relationship is apparent at a very local scale (<10 m), when the
characteristics of the sampled ponds are taken into account (surface area
of pond, length of shoreline). In addition, we identify that dung fungal
spores are principally transported into ponds by surface run-off from the
shores. These results indicate that this method provides a robust
quantitative measure of herbivore population size over time.