Fish, Marmelos Conservation Area (BX044), Madeira River basin, states of Amazonas and Rondônia, Brazil.

The present study provides a species list of fish from the Marmelos River Area – BX044 in the states ofAmazonas and Rondônia in northern Brazil. During a Rapid Ecological Assessment (REA) performed in October andNovember of 2003, 133 fish species from six orders and 24 families were recorded. The most diverse families wereCharacidae (47 species), Cichlidae (15 species), Loricariidae (12 species) and Pimelodidae (7 species). 23 fish specieswere common to the entire river basin and 4 were endemic to the aquatic system studied

Mangal communities of the "Salgado Paraense": Ecological heterogeneity along the Bragança peninsula assessed through soil and leaf analyses

Mangroves in the Bragança peninsula occur in a variety of environmental settings differing in tidal influence and fresh water run-off. The construction of a paved road running through the middle of the peninsula modified the transversal flow of water. Five sites were sampled along this road: I. Coastal site near the village of Ajuruteua, II. Tidal creeks flowing into the lower Caeté river, III. Central lagoons, IV. Avicennia basin forest, and V. Upper Caeté estuary near the village of Acarajó. All but site III, harbored the three common mangroves species Rhizophora mangle, Laguncularia racemosa and Avicennia germinans. Monospecific communities of shrub-like Avicennia germinans stands characterized site III. Soils were highly organic therefore bulk density was inversely correlated to the concentrations of C and N. Sites I and V had the lowest salinity values. The highest salinity was measured ii the Avicennia dominated sites III and IV. Nitrogen showed similar values in all sites, but S was clearly more abundant in sites II and V. Leaf dimensions varied significantly between sites. Considering leaf area expansion as indicator ofstress and δ 13C values as indicator of water use efficiency, site V was more favorable for Rhizophora and Laguncularia while site IV was so for Avicennia. Leaf shape measured as the length/width ratio was more variable in Avicennia and least variable in Rhizophora. Leaf nutrients were not correlated with soil nutrient content. Sodium and Mg were more concentrated in Avicennia leaves while Fe was more concentrated in Laguncularia and Mn in Rhizophora leaves. Avicennia showed the highest N and the lowest Ca concentrations as expected for being a glycinbetaine accumulator and an oxalate-former. δ 15N values indicate that N source for mangroves is essentially the mineralization of organic matter

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio