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E.W Saragih et al. 2010. Effects of endozoochorous seed dispersal on the soil seed bank and vegetation in the woodland area
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Effects of endozoochorous seed dispersal on the soil seed bank and
vegetation in the woodland area
Evi Warintan Saragih 1 , Jan Bokdam 2 & Wim Braakhekke 2
1 Saragih,. Animal Husbandry Faculty. Papua University. Manokwari, Indonesia
2 Bokkdam, Jan and 2 Braakhekke, Wim. Department of Nature Conservation and Plant
Ecology Wageningen University, The Netherlands
Abstract
In the framework of nature conservation and restoration, some experts found the potential of
endozoochorous seed dispersal in a semi-natural landscape. Predicting seed input by large
herbivores through germination test of seeds in dung is needed to figure out the role of large
herbivores. The contribution of large herbivores to ecological restoration sites can be
determined by gathering quantitative information of the dung seed content and compared it with
soil seed bank content and aboveground vegetation in grazed and ungrazed woodland area. The
seed density and species richness of two areas as well as dung content were evaluated by
germination test in the green house to find out effect of grazing regime. The result show that
cattle grazing had a positive effect on distribution of vegetation from lawn area to woodland
area. Species richness in graze area is higher than ungrazed one. Grazing reduced the cover of
grazing sensitive and transport exclusive species to grazed woodland area. Grazing affected the
number of seeds in the soil seed bank sample in the woodland area by creating gaps, stimulating
losses by germination. In conclusions, seed density and species richness in the soil seed bank
are less directly affected by large herbivore but direct effect on above ground vegetation.
Keywords: endozoochorous, seed dispersal, herbivores, vegetation
1. Introduction
Seed dispersal can be defined as the movement of seeds from one place to another by agents
including wind, water and animals. Seed dispersal is a bottleneck for vegetation development
and restoration of isolated (semi) natural relict of nature conservation areas, particularly for
species with short-lived seed banks (Pywell et al. 2002). Therefore studies on seed dispersal
have become an important issue in plant ecology in general and restoration management in
particular. In the framework of nature conservation and restoration, seed dispersal by livestock
has been examined by Bakker et al. (2005), Malo and Suarez (1995a), Mouissie et al. (2005),
Couvreur et al. (2005), Cosyns et al. (2005b) who showed the potential of endozoochorous seed
dispersal in a semi-natural landscape. The contribution of large herbivores to ecological
restoration sites can be determined by gathering quantitative information on the dung seed
content. Predicting seed input by large herbivores through germination test of seeds in dung is
needed to figure out the role of large herbivores.
Seed dispersal contributes to the diversity of plant species in the seed bank. Large herbivores
consume large numbers of seed (Malo and Suarez 1995b) and move long distances, due to their
extensive home-ranges (Haskell et al. 2002). Bakker and Olff (2003) found 183.1 ± 21.1
seedlings per 100 gram dung of cattle in September and 9.8 ± 2.1 seedlings per 100 gram dung
of rabbit in the same month. Most nature conservation areas in The Netherlands consist of open
area (heathland and grassland) and woodland. In some part of this area, large herbivores like
cattle and horses are used as management tools. Defoliation, treading and excretion are direct
effects of large herbivores on the vegetation. Modification of the plant environment is indeed an
indirect effect (Bokdam and Gleichman 2000). Usually large herbivores graze in open areas but
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.