Consequência da mudança de fase sobre atributos funcionais em ecossistemas recifais.

Abstract

Coral reefs are very important to marine biodiversity, in addition they provide important ecosystem services to human populations. Even so, they have been experiencing a reduction in coral cover and species diversity, mainly due to overfishing, pollution, disease and climate change. The association of these anthropic factors with alterations in the structure of benthic communities and loss of resilience is prevalent in the literature, with the possibility of replacing a community dominated by corals with a new stage of dominance by other organisms, a process known as "phase shift". The diversity of functional attributes present in an ecosystem is an important measure of functional diversity, and as it is related to the availability of ecosystem services, it allows a comparison of the state of these environments, before/after changes such as phase shifts. Here, we aim to assess the consequence of a phase shift on functional traits in reef ecosystems. For this, initially, data such as geographic location, time interval, benthic dominance before and after phase shifts were analyzed, as well as possible causes of 29 records found in an extensive literature review. After listing the species involved in these processes of phase change and selection, from the related literature, of the functional attributes that were evaluated, a new review was carried out in search of the traits of these species. After obtaining all the data, descriptive analyzes were performed to assess the overlapping of functions between building and non-building organisms and to discuss the functional consequences of the phase shift process. 29 records were found that describe phase shifts processes in coral reefs. Records in the Caribbean region represented 41.38% of all the records found, which may be related to the high levels of investment in research in the region, as well as anthropic impacts related to the high rate of human occupation from tourism and other economic activities. There was a predominance (62.07%) of processes involving organisms such as sponges, soft corals and echinoids in the replacement of the original phases. However, of the 29 records found, 11 (39.29%) involve macroalgae, which demonstrates the frequency of these organisms in replacing the coral cover on reefs. Comparing the set of attributes of the original and new phases, it was possible to notice negative, positive and neutral consequences. There was a great incompleteness in the data from the studies used in the analyses, requiring a great sampling effort. Finally, it was possible through this work to note that when a reef loses corals, in addition to building capacity, it also loses several other functional attributes related to the species. In addition, the new dominant species bring new attributes that will characterize the new phase of the ecosystem, which may be positive changes. We hope to have contributed to the expansion of knowledge in relation to these processes, in addition to generating subsidies for further studies to be carried out. Research of this nature is important for the possibility of helping managers and governance in measures to mitigate damage, conservation and even the recovery of these ecosystems.