Red‐deer dung increases species diversity but does not influence species composition of open grasslands

Abstract

QuestionsFree‐ranging herbivores are often seen as important endozoochorous dispersal vectors for plant propagules. Dispersal by free‐ranging animals, in contrast to domestic animals, and its effects on vegetation have rarely been studied. We ask what are the effects of deposition of dung on open landscape vegetation, how does it influence vegetation development after disturbance by soil removal, and does it change species richness or composition?LocationThe Doupov Mountains, Czech Republic.MethodsWe established a six‐year experiment in 2015 to study the effects of dung deposition on vegetation of an open grassland landscape. The experiment comprised 300 plots distributed across five fenced site locations and treatments were implemented in partially crossed design, with soil removed (disturbance) and dung pellets deposited; treatments were applied once to five replicates, from June to October 2015. We recorded plant species cover at the beginning of the vegetation seasons of 2016, 2017 and 2021.ResultsDung deposition increased species richness and Ellenberg Indicator Values for nutrients, and these effects were stronger in disturbed plots; however, these effects diminished with time. There were no effects of dung deposition on species composition. In contrast, disturbance affected species diversity, composition, Ellenberg Indicator Values for nutrients, proportion of dung‐dispersed species, but not species richness. Surprisingly, there were no effects of timing of dung deposition.ConclusionsOur results indicate that endozoochorous seed dispersal by red deer impacts vegetation dynamics of this open grassland landscape, but effects are weak and diminish with time. Considering the large seed load in dung, it is possible that endozoochorous seeds from wild herbivores are incorporated into the soil seed bank, where they persist until appropriate ecological conditions for germination arise.