Landscapes Forest and Global Change - ESA - Escola Superior ...

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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only in the ungrazed woodland. In total, 19 lawn species found in both soil seed bank. Two
lawn species (Cirsium vulgare and Veronica arvensis) only present in ungrazed area while five
species (Genista anglica, Juncus buffonius agg, Plantago major, Sonchus oleraceus and
Lamium purpureum) only present in grazed area. However only Jasione montana, Lamium
purpureum & Sonchus oleraceus were found in the dung and those species dispersed during the
winter. Number of seeds is higher in the soil seed bank ungrazed area than soil seed bank grazed
area but frequency of lawn species in soil seed bank of grazed area is higher than ungrazed area.
Total frequency lawn species in grazed area (4.6) is higher than ungrazed area (4.2)
4. Discussion
4.1 The effects of cattle on woodland vegetation
Cattle play an important role in the vegetation which show by species richness as well as cover
was higher in the grazed woodland vegetation than ungrazed ones. Many of these are the
characteristic species of pasture and heathland (Senecio jacobaea, Cerastium fontanum,
Danthonia decumbens, Plantago lanceolata, Poa pratensis, Ranunculus repens, Rumex
acetosella, Trifolium repens), clearings (Senecio sylvaticus) or fringes (Rubus idaeus, Teucrium
scorodonia). Grazing reduced the cover of grazing-sensitive species: Ceratocapnos claviculata,
Dryopteris carthusiana, and Vaccinium myrtillus. Agrostis capillaris has the same average
cover in grazed and ungrazed but species frequency in grazed area is higher than in ungrazed
area. In addition, Deschampsia flexuosa and Galium saxatile had the same species frequencies
but average cover of species was higher in grazed vegetation. This evidenced present
contribution of cattle-dispersed lawn species in the woodland area by creating understory gaps,
stimulate germination and growth of lawn species in the understory vegetation of the woodland.
Seven species of dung samples (Erigeron Canadensis, Epilobium sp, Juncus bufonius agg,
Lolium perenne, Medicago lupulina, Ranunculus acris) were absent from aboveground
vegetation in the grazed area due unable to cope with the environmental condition and
predators. It seemed that the number of species aboveground is not influenced by the number of
species in the soil seed bank, as the numbers of species in the soil seed bank depend on the
number of persistent seeds. The floristic composition of the seed bank is not a mirror reflecting
the vegetation composition, but rather a record of a long-term turnover of species and many
different events which in various periods of time influence the input and output of seeds
(Falinska 1998).
4.2 Contribution of endozoochorous seed dispersal to lawn species establishment
The dung deposited by herbivores (cattle) increased the diversity in the grazed woodland
vegetation that could cause by cattle facilitated the arrival of species from open area to the
woodland area and good condition provided by dung for germination. Dung creates places free
from vegetation (gaps) with high nutrient availability (Dai 2000) and dung with sufficient
water- retention capacity provide a safe site for a number of species particularly those from
nutrient-rich habitat that able to grow fast and root in underlying soil (Mouissie 2005). The right
conditions for germination and establishment, which could be linked to the change in nutrient
concentrations, were provided by dung and might have also generated positive effects on the
germination of some of the species present in the soil seed bank (Traba et al. 2003). Eleven
light demanding species (Danthonia decumbens, Poa pratensis, Rumex acetocella, Ranunculus
repens, Rosa canina Rubus idaeus, Sorbus ocuparia, Sinecio sylvaticus, Sambucus nigra,
Teucrium scorodonia, Trifolium repens) from grazed vegetation were absent in the species dung
sample. Those species might be unpalatable or not providing seeds during the study period.
Endozoochorous seed dispersal explained the exclusive occurrence of Cerastium fontanum,
Holcus lanatus, Plantago lanceolata, Poa trivialis and Senecio jacobaea the in grazed
vegetation. Most of them were exclusively present in the summer dung, except for Holcus
lanatus which was found in both seasons. Those species are light demanding (L- value≥6). Total
cover and total frequency of lawn species is higher in vegetation of grazed area than in the
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.