Endozoochory decreases environmental filtering imposed to seedlings

Abstract

Questions Recruitment microsites are imposed on plants, first by seed dispersal and then by the environment. Different seed dispersal vectors could decrease or increase the environmental filtering imposed on seedlings, depending on their specificity to deliver seeds to suitable microsites for germination and establishment. We addressed the hypothesis that endozoochory reduces the environmental filtering imposed to seedlings to a larger extent than does anemochory. We predicted that seedlings from animal‐dispersed species should show a higher degree of environmental coupling. Location Northern Patagonian Andean region of Argentina, 40–42° S. Methods We characterized the relationship of seedlings, saplings and reproductive individuals to total radiation, air temperature and relative humidity for 16 woody species growing in 25 plant communities of different post‐fire ages in temperate forests of southern South America. Results Seedlings and saplings of endozoochorous species occurred under more similar environmental conditions than seedlings and saplings of anemochorous species. Basically, the mean difference in plant–environment correlation coefficients between saplings and seedlings was <0.2 for all endozoochorous species and >0.2 for all anemochorous species for all environmental variables. Comparisons between dispersal modes were also statistically significant before and after controlling for phylogenetic relationships among species. Even though saplings and seedlings of endozochorous species tended to occur under similar environmental conditions, we did not find evidence that saplings and seedlings co‐occur in the same physical microsites. Finally, we did not find evidence either that seedlings of endozoochorous species tended to occur differentially underneath reproductive individuals of the same species (i.e. more seeds falling by gravity beneath maternal plants). Conclusions The tighter coupling between seedlings of endozoochorous species and environmental factors persisting to the sapling stage suggests that relying on animals for seed dispersal reduces mortality costs during the early stages of recruitment by reducing the environmental filtering imposed on seedlings.

Consequences of Seed Dispersal for Plant Recruitment in Tropical Forests: Interactions Within the Seedscape

“…A particular benefit of vertebrate dispersal over wind dispersal is that a greater proportion of seeds may land in similar environments as the parent tree (Cavallero et al . ).…”

“…Suitable habitats include high-light areas (e.g., treefall gaps, forest edges) for light-dependent tree species, tree canopies for epiphytes, or host trees for parasitic species. A particular benefit of vertebrate dispersal over wind dispersal is that a greater proportion of seeds may land in similar environments as the parent tree (Cavallero et al 2012).…”

Dispersion and aggregation patterns of tree species in Araucaria Forest, Southern Brazil

“…In altered secondary forests, the tendency of aggregation of zoochoric species may occur due to habitat fragmentation, for absence of dispersant animals the seeds of the trees tend to be dispersed near the mother plant (Wilson et al 2004, Nathan 2006. However, in well-conserved secondary forests where dispersal animals are present, seed aggregation may occur in greater proportion under nests or along paths used by animals that travel small and long distances (Schupp et al 2002, Boyer et al 2006 and in environments similar to the mother plant (Cavallero et al 2012). In the present study, several ecological factors may be contributing to the aggregation of zoochoric species (see Boyer et al 2006, Beckman andRogers 2013).…”

Consequences of disperser behaviour for seedling establishment of a mistletoe species

“…The majority of tropical and many temperate woody plant species are dispersed by frugivorous animals that eat fruits and defecate or regurgitate seeds (Herrera 2002). Therefore, a central question in the ecology of seed dispersal is to what extent seed dispersers are able to transport seeds to microsites that increase the chance of seedling establishment (Wenny & Levey 1998;Wenny 2001;Cavallero et al 2012). Therefore, a central question in the ecology of seed dispersal is to what extent seed dispersers are able to transport seeds to microsites that increase the chance of seedling establishment (Wenny & Levey 1998;Wenny 2001;Cavallero et al 2012).…”

“…The behaviour of animals transporting seeds to specific microsites could greatly affect plant fitness (Russo et al 2006;Schupp et al 2010;Morales et al 2012;Sasal & Morales 2013). Therefore, a central question in the ecology of seed dispersal is to what extent seed dispersers are able to transport seeds to microsites that increase the chance of seedling establishment (Wenny & Levey 1998;Wenny 2001;Cavallero et al 2012). Animal behaviour is particularly critical in plants such as mistletoes (i.e.…”