Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, 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 organism 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 neglected 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 lost

Efeito da pressão antrópica sobre igarapés na Reserva Florestal Adolpho Ducke, área de floresta na Amazônia Central

Foram investigadas variáveis físico-químicas e químicas de ambientes aquáticos, em área de floresta primária de terra firme, próxima à área urbana, no município de Manaus. Os cursos de águas superficiais investigados drenam tanto área de floresta primária como urbanizada e, na região, são chamados igarapés. Dois desses igarapés têm suas nascentes na área urbana, adentram a área de floresta e lá se juntam. Ainda dentro da mesma área o igarapé resultante encontra-se com um outro que drena apenas área de floresta primária. Neste estudo foram pesquisadas as variáveis ambientais: pH, condutividade elétrica da água, os cátions (Na+, K+, Ca2+, Mg2+ e Fe2+) e material em suspensão. Foi possível observar diferenças significativas nas médias da concentração de íons hidrogênio, na condutividade elétrica e na quantidade de material em suspensão, entre os igarapés estudados. No igarapé cuja nascente encontra-se dentro da reserva, os valores médios correspondentes ao pH, condutividade elétrica e material em suspensão foram, respectivamente, 4,47; 6,44 mS cm-1 e 1,25 mg L-1; e os valores mais elevados registrados nos impactados foram 6,84, 141,50 mS cm-1 e 9,50 mg L-1. Os resultados mostram que o igarapé que drena área de floresta mantém suas características naturais por estar protegido das atividades antrópicas, e os que provêm da área urbana encontram-se impactados.Physicochemical and chemical variables from water environments were investigated in an area of upland primary forest, near an urban area, in the municipality of Manaus. The investigated surface water streams drain both primary forest and urbanized areas, and are called igarapés in the region. The headwaters of two of these streams are in the urban area, and they run to the forest area and join to make up another stream, and later are joined with another stream which headwaters are located inside the primary forest. This study encompassed the following environmental variables: pH, water electrical conductivity, Na+, K+, Ca2+, Mg2+ and Fe2+ cations and suspended material. It was possible to see significant differences in the concentration of hydrogen ions, electrical conductivity and in the suspended material content, among the studied streams. In the stream in which the headwaters are within the reserve, the mean values corresponding to pH, electrical conductivity and suspended material were 4.47; 6.44 mS cm-1 and 1.25 mg L-1, respectively; and the highest values found in the impacted ones were 6.84, 141.50 mS cm-1 and 9.50 mg L-1. The results show that the stream which drains the forest area maintains its natural characteristics as it is protected from human activities, and the ones which come from the urban area are impacted

Riparian Deforestation Affects the Structural Dynamics of Headwater Streams in Southern Brazilian Amazonia

Comparative studies of streams with altered versus conserved riparian zones are important to evaluate the degree of alterations caused by inappropriate use of these streams’ vital buffer zones. The aim of this study was to determine the impact of riparian deforestation on the habitat structure of southern Brazilian Amazonian headwater streams, as well as to provide elements for impact assessment and the monitoring of these water bodies. We selected ten sites and two headwater streams at each site; one stream was located in an area with preserved riparian vegetation (pristine streams) and the other stream in a deforested riparian zone (altered streams). Stretches of these streams were analyzed across hydrological periods (dry period, beginning of the rainy period, and end of the rainy period) for hydro-morphological aspects, water physical-chemical variables, and habitat integrity (proportion of forestation in buffer zones and habitat integrity index). Compared to pristine streams in all the hydrological periods analyzed, altered streams presented lower oxygen concentration (~1.0 mg/L), an increase of 1 °C in water temperature, and less organic material availability. We found that riparian deforestation affects habitat structure variability among hydrological periods, making them more homogeneous. Therefore, beyond the necessary broadening of the spatial scale of studies in this region, monitoring these understudied headwater stream environments is also crucial for determining the magnitude of deforestation effects on these vulnerable aquatic ecosystems. © Monica Elisa Bleich, Amanda Frederico Mortati, Thiago André and Maria Teresa Fernandez Piedade