ABSTRACT
The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
Subject(s)
Plant Leaves , Carbon Cycle , Carbon/metabolismABSTRACT
Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.
Subject(s)
Biodiversity , Floods , Rivers , Trees , Brazil , ForestsABSTRACT
Abstract The Brazilian state of Acre is located in the southwestern Amazon and it is characterized by a humid tropical forest vegetation that covers plains and mountains. Up to this point, the composition of termite species in the state is not known. The aim of this study was to provide a checklist of termite species or recognizable taxonomic units for the state of Acre. Sampling was conducted through field expeditions at the Serra do Divisor National Park, Chandless State Park, Humaitá Forest Reserve, and Chico Mendes Environmental Park using a standardized rapid termite inventory protocol in the first two areas and active searching collections in the others, without a specific protocol. This study also included occurrence records published in the scientific literature. A total of 128 species and morphospecies of termites were found in Acre, distributed across 59 genera and four families. The most frequently occurring species in Acre was Heterotermes tenuis (Hagen, 1858). The study also identified six new species records for Brazil. The predominant feeding groups were soil-feeders and wood-feeders, as expected from data obtained from surveys in humid tropical forests. Despite the significant number of new records for Acre (112), it is concluded that a larger sampling effort is still required, as many areas of the state have not yet been studied for termites.
Resumen O estado brasileiro do Acre está localizado no sudoeste da Amazônia e é caracterizado por uma vegetação de floresta tropical úmida que cobre planícies e montanhas. Até então, a composição de espécies de térmitas no estado não é conhecida. O objetivo desse estudo foi construir um checklist de espécies ou unidades taxonômicas reconhecíveis de térmitas para o estado do Acre. A amostragem foi conduzida através de expedições de campo no Parque Nacional da Serra do Divisor, no Parque Estadual Chandless, na Reserva Florestal Humaitá, e no Parque Ambiental Chico Mendes utilizando o protocolo rápido de diversidade de térmitas nas duas primeiras áreas e coletas avulsas nas demais, sem um protocolo específico. Este estudo também incluiu registros de ocorrência publicados na literature científica. Um total de 128 espécies e morfoespécies de térmitas foram encontradas no Acre, distribuídas em 59 gêneros e quatro famílias. A espécie de ocorrência mais frequente no Acre foi Heterotermes tenuis (Hagen, 1858). O estudo também identificou seis novos registros de espécies para o Brasil. Os grupos alimentares predominantes foram os humívoros e xilófagos, como esperado a partir de dados obtidos de pesquisas em florestas tropicais úmidas. Apesar do número significativo de novos registros para o Acre (112), conclui-se que ainda é necessário um esforço amostral maior, uma vez que muitas áreas do estado ainda não foram estudadas para térmitas.