Inter-annual climate variation is an important driver of community and ecosystem dynamics and a potential axis of niche partitioning. However, the effects of climate on fecundity in diverse communities, e.g. tropical rainforests, remain poorly understood, owing to limited data and absence of analytical approaches. Furthermore, little is known about the ecology of most species, motivating the search for generality in species climate responses. Here, we couple long-term demographic data from three Neotropical rainforests (in Puerto Rico, Panama, and Peru) and a state-space Bayesian joint model of tree growth, survival, and fecundity to ask 1) which climate factors (precipitation, radiation, and temperature) are the strongest drivers of inter-annual variation in fecundity? and 2) are species differences in functional traits and biogeography linked to divergent responses to climate? We expected that species traits associated with acquisitive versus conservative resource use strategies would be associated with climate response, such that acquisitive species are most sensitive to drought and high temperatures.
We found that sites differed in the interspecific diversity of fecundity responses to climate. Species responses to climate were most diverse at the Panama site, where species exhibited significant, divergent (i.e. opposing sign) associations with inter-annual climatic variation for all variables tested, suggesting climate variation promotes local species coexistence. This result was consistent for 1-year lagged climate effects. In contrast to the Panama site, at the Peru site there were few significant and divergent associations with climate. There, species with significant climate responses exhibited greater reproduction in warmer years and years with more radiation, and less reproduction in wetter years and years with wetter dry quarters. At the Puerto Rico site, there were few species with significant climate responses. Several functional traits were significantly associated with climate responses at the Panama site (where we had the most data). The strongest association was that species with lower maximum height tended to exhibit more strong positive fecundity responses to rainfall, compared to weaker associations for taller species. Together, our individual-based fecundity results indicate that inter-annual climate variation may influence local tree community diversity and that directional climate change may result in shifts in the functional composition of communities.