The home-field advantage (HFA) hypothesis establishes that plant litter decomposes faster at ‘home’ sites than in ‘away’ sites due to more specialized decomposers acting at home sites. This hypothesis has predominantly been tested through ‘yes or no’ transplanting experiments, where the litter decomposition of a focal species is quantified near and away from their conspecifics. Herein, we evaluated the occurrence and magnitude of home-field effects on the leaf litter decomposition of Myrcia ramuliflora (O.Berg) N. Silveira (Myrtaceae) along a natural gradient of conspecific litterfall input and also if home-field effects are affected by litter and soil traits. Litter decomposition of M. ramuliflora was assessed through litterbags placed in 39 plots in a tropical heath vegetation over a period of 12 months. We also characterized abiotic factors, litter layer traits, and litter diversity. Our results indicated the occurrence of positive (i.e. Home-field advantage) and negative (i.e. Home-field disadvantage) effects in more than half of the plots. Positive and negative effects occurred in a similar frequency and magnitude. Among all predictors tested, only the community weighted mean C/N ratio of the litterfall input was associated with home-field effects. Our results reinforce the lack of generality for home-field effects found in the literature and thus challenge the understanding of litter-decomposer interaction in tropical ecosystems.

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Studies from the past two decades indicate the important role of functional diversity and litter identity as a determining factor in decomposition. So far, researchers have search to understand the effects of litter diversity in opposite environmental contexts, in which the abiotic pathway prevails over the biotic pathway. We search to test the effects of the functional diversity of litter on decomposition in areas under vegetation (i.e., more favorable to biological decomposition), and in areas exposed to the sun (i. e., more favorable to photodegradation), prioritizing the litter functional diversity. We used an experimental approach in situ with litterbags in two different environmental contexts in a rainforest in RN, Brazil. We used four species with different specific leaf areas (SLA) and put in mono and bicultures, totaling 120 litterbags, placing 60 of them in the most exposed to the sun and the rest in the shaded environment. We observed that the decomposition rate in habitats with greater exposure to photodegradation was on average 34% higher than that observed in habitats with vegetation. There were also effects of diversity in some treatments, indicating the effect of functional identity, in which combinations of litter leaf with greater differences in SLA values (i. e., discrepant bicultures) showed a slower decomposition in bicultures than in the corresponding monocultures. With the predictions of climate change, regions such as rainforest can become increasingly arid, so our work suggests that in these environments the high rate of photodegradation can accelerate the decomposition of the litter with high SLA, With the predictions of climate change, certain regions such as rainforest can become increasingly arid, so our work suggests that in these environments the high rate of photodegradation can accelerate the decomposition of the litter with high SLA, besides, to retard leaf litter decomposition of species with discrepant SLA's.

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Aims: We evaluated the relative importance that biodiversity factors, abiotic conditions, and vegetation structure have on monthly leaf litter production. We tested if biodiversity drives leaf litter production through the increase in species richness or community-weighted mean traits regardless of the influence of other biodiversity factors that reflect species niche differentiation, such as phylogenetic and functional diversities. We also tested if precipitation imposes greater influence on the production than any asynchronous effects between species that result from temporal niche partitioning. Location: Seasonal heath vegetation that covers white-sand coastal areas in northeastern Brazil. Methods: We conducted an observational study across 41 25-m 2 permanent plots to sample leaf litter production of the vegetation during 18 months from January 2016 to June 2017 at monthly intervals. We used structural equation modeling in combination with linear mixed models to test the above-mentioned hypotheses. Results: Our study encompassed 22 focal species. Species richness was the only biodiversity factor to influence leaf litter production, although its effect was weak, suggesting that the chance of including high-yielding species by increasing richness enhances the production regardless of the degree of species niche complementarity through functional and phylogenetical dissimilarities. We also observed a major control of precipitation on leaf litter production, as well as a lack of interaction between species richness and its temporal dynamic of production, demonstrating the key role of climate-mediated controls. Conclusion: We believe that plant diversity loses importance for ecosystem functioning in ecological contexts where the entire community responds similarly to abiotic pressures, particularly if the ecosystem process is marked by strong temporal dynamics. Our study provided empirical support for this line of reasoning since the seasonal heath vegetation responded mostly to rainfall seasonality.