Phylogenetic structure of aquatic plant assemblages in a climate sequence

Abstract Floristic studies of aquatic plants and flora associated with aquatic ecosystems carried out in the Neotropical region have demonstrated the predominance and co-occurrence of the same plant families under different climatic conditions. One way to interpret this co-occurrence of groups with non-random patterns in assemblages is to understand their phylogenetic structure. Herein, we present an investigation that studied the rule of phylogenetic assembly on plants associated with reservoirs in a tropical climosequence in Northeast Brazil. We studied eight areas during the dry and rainy periods and characterized their climatic, chemical, and trace elements, as well as richness, diversity, and phylogenetic structure of their assemblages. We found a predominance of the families Fabaceae, Poaceae and Cyperaceae, especially in border areas. Among the species surveyed, we highlight those with amphibian life-form, autochoric-type dispersion syndrome and the taxa with patterns of wide geographical distribution. We observed that the seasonal effect ruled patterns of phylogenetic structure with tendency for non-co-familiarity. Water quality and sediment were the abiotic factors most efficient as predictors of richness and variations in phylogenetic metrics. In this sense, the family co-occurrence identified in the assemblages was less deterministic than expected through non-randomness, because temporally, guilds were distinctly structured in function of seasonality. Resumo Estudos florísticos de plantas e floras associadas a ecossistemas aquáticos realizados na região Neotropical têm demonstrado a predominância e coocorrência das mesmas famílias de plantas em diferentes condições climáticas. Uma forma de interpretar essa coocorrência de grupos com padrões não aleatórios em assembléias é entender sua estrutura filogenética. Aqui, apresentamos uma investigação que estudou a regra de montagem filogenética em plantas associadas a reservatórios em uma climosseqüência tropical no nordeste do Brasil. Estudamos oito áreas durante os períodos seco e chuvoso e caracterizamos seus aspectos climáticos, fatores químicos e elementos-traços, bem como a riqueza, diversidade e estrutura filogenética de suas assembleias. Encontramos predominância das famílias Fabaceae, Poaceae e Cyperaceae, principalmente nas áreas de borda. Dentre as espécies levantadas, destacamos aquelas com forma de vida anfíbia, síndrome de dispersão do tipo autocórico e táxons com padrões de ampla distrib