Impact of different‐sized herbivores on recruitment opportunities for subordinate herbs in grasslands

Abstract

Abstract. Potential effects of herbivores on plant species diversity depend on herbivore size, species and density. In this study we examine the effect of different-sized herbivores (cattle and rabbits) on recruitment of subordinate herbs in grasslands. We show that in a grazed floodplain, grassland plant species richness is mainly determined by the presence of many species of subordinate herbs. These herbs experience high colonization and extinction rates. We conclude that the creation of colonization opportunities for subordinate herbs plays a crucial role in maintaining plant species richness in productive grasslands. We found that cattle disperse large amounts of seeds via their dung, over ten times more than rabbits. Rabbits create more and on average larger bare soil patches than cattle. In a field experiment artificial disturbances improved germination success tremendously for four tested herb species. We found that bare soil is the best regeneration site, while cattle dung gave a too strong nutrient stimulus, resulting in tall vegetation and therefore light limitation. These results can be confirmed with results from field monitoring plots where plant species richness was positively related to the occurrence of bare soil patches. Therefore both large and small herbivores have a major impact on dispersal and colonization, but for different reasons. Cattle are identified as most important for seed dispersal whereas rabbits have a main effect as creators of disturbances. These results emphasize the importance of distinguishing between herbivore species in assessing their (potential) effects.

Dispersal by cattle of salt-marsh and dune species into salt-marsh and dune communities

“…Yet, the species composition in dung of herbivores found in other studies suggests that the dispersal of seeds between different habitats is a more common phenomenon than expected. Dung collected in a grassland-woodland mosaic in the Netherlands contained seeds of all habitat types (Bakker and Olff 2003). This was also the case in a heathlandgrassland-woodland area (Mouissie et al 2005b) and in a heterogeneous coastal habitat in Belgium Fig.…”

Farklı Cins Hayvan ile Otlatılan Meraların Sağlık ve Ekolojik Alan Sınıflaması

“…2011). Büyük baş ile küçükbaş hayvanlar karşılaştırıldıklarında, büyük baş hayvanlar hem daha fazla ot ve tohum tüketmekte hem de tüketmiş oldukları tohumlar sindirim sistemlerinden daha uzun sürede geçtiği için tohumları daha uzak alanlara taşınmaktadırlar (Bakker and Olff 2003). Büyük baş hayvanların bıraktığı dışkılar bünyesinde bulundurduğu tohumların yayılmasını sağlarken, mevcut bitki örtüsünün yapısının Tarla Bitkileri Merkez Araştırma Enstitüsü Dergisi, 2016, 25 (Özel sayı-2):174-178 Araştırma Makalesi (Research Article) …”

Effect of cattle activities on gap colonization in mountain pastures

“…First they directly create the gaps by hoof action (BAKKER & OLFF 2003). SILVERTOWN & SMITH (1988) showed that heavier grazing increased the frequency of canopy gaps.…”

“…With the gap environment, these three factors induced by cattle activity can be considered as supplementary environmental filters (sensu ZOBEL 1997) that exclude different subsets of the total grassland flora from the gaps. Dung and urine deposition influence gap colonization in two ways: (1) fertilization involving a stimulation of plant growth, (2) addition of seeds promoting new species (MALO et al 1995, BAKKER & OLFF 2003. Herbage removal induces a loss of biomass and a change in light competition between species (GRIME 2001).…”