Flooding regime drives tree community structure in Neotropical dry forests

Abstract

Questions Riverine and associated vegetation communities are periodically affected by floods. However, there have been few quantitative studies on the structural responses of Neotropical tree communities in semi‐arid regions to this perturbance. Here, we ask whether flooding regimes and soil attributes affect tree species diversity, composition, community structure, and soil attributes in Neotropical dry forests. Locations Southeast Brazil. Methods We sampled 120 forest plots of 400 m² totaling 4.8 ha across four tributaries of the São Francisco River with plots situated in areas representing three flooding regimes: (a) annually flooded; (b) occasionally flooded; and (c) never subjected to flooding. Using linear mixed‐effects models, we modelled how flooding regime and soil properties (fertility and texture) affect vegetation diversity (species richness), species composition and structural attributes (abundance of individuals, above‐ground biomass [AGB], and a community‐weighted trait average of multistemness [CWMms]) of these forest plots. Results Species richness in the annually flooded forests was significantly lower than in occasionally flooded or never flooded forests, in agreement with our models, which showed that flooding regime was a significant predictor for this variable. Flooding regime was a significant predictor of CWMms, with plots in annually flooded forest sites having the highest CWMms values. Soil chemical attributes were a significant predictor of AGB across all plots but not between flooding regime categories. Conclusions In Neotropical dry forests, environmental filters established by flooding can lead to differences among distinct biomes in vegetation structure, diversity patterns as well as system productivity. Conservation strategies for dry forests should therefore take these factors into consideration. Our study also highlights annually flooded dry forest as a significant component of the regional diversity of dry forests deserving of management attention.

Pit and tracheid anatomy explain hydraulic safety but not hydraulic efficiency of 28 conifer species

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Tree regeneration characteristics in limestone forests of the Cat Ba National Park, Vietnam

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Tree Regeneration Characteristics in Limestone Forests of the Cat Ba&nbsp;National Park, Vietnam

“…However, the marginal R 2 values of each model (Table 4) were very small, so although we can con rm a link between species richness ratios and environmental factors, we did not observe a strong relationship. We assume that other unidenti ed factors or factors functioning on a larger scale must be considered such as rainfall seasonality [69], water erosion [70,71], and ooding period [72,73]. In particular, increasing extreme events can have major impacts on seedling establishment effective over extensive areas.…”