Interspecific associations in seed arrival and seedling recruitment in a Neotropical forest

Abstract

Abstract. Contagious seed dispersal refers to the tendency for some sites to receive many dispersed seeds while other sites receive few dispersed seeds. Contagious dispersal can lead to interspecific associations in seed arrival, and this in turn might lead to interspecific associations in seedling recruitment. We evaluate the extent of spatially contagious seed arrival, the frequency of positive interspecific associations in seed arrival, and their consequences for seedling recruitment at the community level in a tropical moist forest. We quantified seed arrival to 200 passive seed traps for 28 yr of weekly censuses and seedling recruitment to 600 1-m 2 quadrats for 21 yr of annual censuses on Barro Colorado Island, Panama. We assessed whether spatially contagious seed dispersal was more important among zoochorous species than among anemochorous species, increased in importance with similarity in fruiting times, and led to interspecific associations in seed arrival and seedling recruitment. We controlled adult seed source associations statistically to evaluate predicted relationships. We found that spatially contagious seed arrival was widespread among zoochorous species, but also occurred among anemochorous species when the strong, consistent trade winds were present. Significant interspecific associations in seed arrival were more likely for pairs of species with zoochorous seeds and similar fruiting times and persisted through seedling recruitment. Thus, interspecifically contagious seed dispersal affects local species composition and alters the mixture of interspecific interactions through the seed, germination, and early seedling stages in this forest. Future investigations should consider the implications of interspecific association at the regeneration stages documented here for later life stages and species coexistence.

Beyond the fast–slow continuum: demographic dimensions structuring a tropical tree community

“…by conserving existing seed sources that are placed above the main canopy and can thus supply distant disturbed areas with seeds via wind or animal dispersal (6 and 13 out of the 20 most extreme long‐lived pioneers in our study respectively; Wright et al . ). In contrast, tropical short‐lived pioneers form seed banks (Dalling et al .…”

Characteristics and drivers of plant virus community spatial patterns in US west coast grasslands

“…On the other hand, facilitation through heterologous encapsidation may contribute to the high rate of aggregation between MAV and RPV, which do not share a vector (Wen and Lister ). Interestingly, the strong effect of shared dispersal mechanisms on community spatial patterns has also been demonstrated for plants with animal‐dispersed seeds (Mellado and Zamora , Wright et al ).…”

“…The strong signal of co‐transmission in pathogen spatial patterns highlights vector control as a coinfection management strategy. While the effects of co‐transmission are analogous to effects of co‐dispersal observed for free‐living organisms (Mellado and Zamora , Wright et al ), pathogen‐specific factors can shape pathogen community spatial patterns as well. Importantly, pathogen spatial patterns are intrinsically linked with other living organisms – their hosts.…”

Resolving the paradox of clumped seed dispersal: positive density and distance dependence in a bat‐dispersed species

“…In the 50‐ha plot on BCI, 85% of all woody species recorded in the main censuses to date with known dispersal modes are animal‐dispersed, 18% of which are bat‐dispersed (Wright et al. ). At least for the seedling stage, the apparent paradox of clumped dispersal in one such species can be explained by positive dispersal effects, especially to under bat feeding roosts where seedling survival was enhanced, combined with a lack of negative density‐dependent effects.…”