The dispersal of vascular plants in a forest mosaic by a guild of mammalian herbivores

Abstract

Endozochorous seed dispersal by herbivores can affect plant spatial dynamics and macroecological patterns. We have investigated the number and species composition of viable seeds deposited in faeces of a full guild of macroherbivores (four deer and two lagomorph species) in a forest in eastern Britain. One hundred and one plant species germinated from faecal pellet material, 85 of which were among the 247 vascular plant species recorded in the forest. However, three species - Chenopodium album, Urtica dioica and Agrostis stolonifera - comprised 56% of the seedlings recorded. Of the species recorded in faecal samples, 36% had no recognised dispersal mechanism, while very few (7%) were adapted to endozoochorous dispersal (fleshy fruit or nut). The number of species dispersed by the herbivores was ranked Cervus elaphus and Dama dama (96) > Capreolus capreolus (40) > Muntiacus reevesi (31) > Oryctolagus cuniculus (21) > Lepus europaeus (19), with the other taxa dispersing subsets of those dispersed by C. elpahus and D. dama. The invasive M. reevesi deposited the fewest seeds per gram of faecal pellet material (0.4 g-1) and hence fewer seeds per unit area than other deer species despite their numerical dominance, while C. elaphus/D. dama deposited the most (0.43 seeds m -2 year-1). Due to differences in faecal seed density among habitats combined with the ranging behaviour of animals, more seeds were deposited in younger stands, enhancing the potential contribution of macroherbivores to population persistence by dispersal and colonisation in a successional mosaic. © 2007 Springer-Verlag.