Large herbivores as a driving force of woodland-grassland cycles. The mutual interactions between the population dynamics of large herbivores and vegetation development in a eutrophic wetland

Promotie

Large herbivores as a driving force of woodland-grassland cycles. The mutual interactions between the population dynamics of large herbivores and vegetation development in a eutrophic wetland

Promovendus mr. ing. P (Perry) Cornelissen
Promotor prof.dr. F (Frank) Berendse
prof.dr. KV (Karle) Sykora
Copromotor dr ir J Bokdam
Organisatie Wageningen University, Plant Ecology and Nature Conservation
Datum

di 10 januari 2017 16:00 tot 17:30

Locatie Auditorium, building number 362
Generaal Foulkesweg 1
362
6703 BG Wageningen
0317-483592
Conservation and restoration of biodiversity are major objectives for managers of nature reserves. In many cases large herbivores are used to achieve these goals. The common strategy of controlled grazing with large wild and domestic herbivores at low stocking rates has been challenged by a more ‘natural’ grazing strategy, which is part of the so called ‘rewilding’ concept. In this concept, unmanaged populations of large herbivores are assumed to play a key-role in the large scale dynamics of landscapes by driving cyclic woodland-grassland mosaics. The question is whether this assumption is correct in all cases. This study showed that in a eutrophic environment such as the Oostvaardersplassen, unmanaged large herbivores are able to break down woody vegetation and create grasslands. Competition among large herbivores and between large and small herbivores (i.e. geese) are mainly responsible for this transition. Competition and the transition into short grazed grasslands were also responsible for the decrease of the largest herbivore in this system: cattle. This raised the question whether large herbivores can coexist in fenced, small, homogeneous eutrophic wetlands. The study showed that resource partitioning may be a better mechanism for long term coexistence than temporal variability due to climatic extremes. To provide opportunities for resource partitioning, heterogeneity of the system should be increased by enlarging and connecting the area to other nature reserves. Until now, the study has shown that a few conditions for the wood-pasture cycle are met. It will take more time to see if the other conditions will also be met and if large herbivores are indeed drivers of wood-pasture cycles in all cases.