Gradientes ambientais como filtros na composição de insetos aquáticos do Cerrado-Caatinga, Brasil

The patterns of aquatic insect diversity are influenced by landscape structure and environmental gradients that can be altered significantly through changes in land use. The aim of the present study was to verify if the patterns of diversity of the orders Odonata and Trichoptera vary significantly between preserved and altered sites, along a gradient of environmental impact. Data were collected on the structural and environmental characteristics of the stream, and the assemblages of aquatic insects at seven sampling points in a Cerrado-Caatinga ecotone of northeastern Brazil, in the dry seasons of 2018 and 2019. The results indicated that altered streams had higher electrical conductivity and lowest HII (habitat integrity index) values in comparison with the preserved ones, being determinant in the distribution of genera, and low pH values increased genera richness, informations that can guide management strategies for biodiversity conservation. Which supports the conclusion that the diversity of aquatic insects is determined by the influence of environmental filters in the streams.Os padrões de diversidade de insetos aquáticos são influenciados pela estrutura da paisagem e gradientes ambientais que podem ser alterados significativamente através de mudanças no uso da terra. O objetivo do presente estudo foi verificar se os padrões de diversidade das ordens Odonata e Trichoptera variam significativamente entre locais preservados e alterados, ao longo de um gradiente de impacto ambiental. Foram coletados dados sobre as características estruturais e ambientais do córrego e das assembleias de insetos aquáticos em sete pontos de amostragem em um ecótono Cerrado-Caatinga do Nordeste, Brasil, nas estações secas de 2018 e 2019. Os resultados indicaram que córregos alterados apresentaram maiores valores de condutividade elétrica e menores valores de IIH (índice de integridade de habitat) em comparação aos preservados, sendo determinantes na distribuição de gêneros, e baixos valores de pH aumentaram a riqueza de gêneros, informações que podem orientar estratégias de manejo para a conservação da biodiversidade. Reforçando a conclusão de que a diversidade de insetos aquáticos é determinada pela influência de filtros ambientais nos riachos

Environmental spatial-temporal heterogeneity of streams in a Cerrado-Caatinga ecotone

Environmental spatial-temporal heterogeneity is an important factor for structuring the biodiversity of ecosystems, including lotic systems that have been strongly influenced by land use and occupation. Thus, the present study aimed to identify if there was a spatial-temporal difference of the structural and physical-chemical variables which the streams of the Environmental Protection Area of the Inhamum, as well as if there was difference of environmental heterogeneity which the samples during the period of 2012 to 2015. The ordernation indicated temporal effects on the streams, because there were two groups formed, the first formed by the samples of 2012-2013 and the other by 2014-2015, but which did not present differences as to their heterogeneity. Temperature, conductivity, depth, width and flow were important in the structuring of the streams, but due to being in an area with a wide canopy cover and high habitat integrity, there was a small range of variation in the values of these variables. These results demonstrate the importance of the maintenance of the canopy cover to guarantee the habitat integrity and to provide the conservation of the environmental characteristics of streams in tropical biomes

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

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 understanding 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,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 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 underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 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,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 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

Trichomes are effective against folivory

Ecosystems that show greatest heterogeneity have a greater amount of interactions between organisms that are part of their food chains, among these relationships exists the herbivory, thus the present study aims to evaluate the feeding preference of herbivory insects for plants in an area of capoeira vegetation, the hypothesis tested is that insects prefer plants with less trichomes. The survey was performed at the Federal Institute of Maranhão Campus Caxias, in November 2016, during which 600 leaves of different species were sampled, most of which did not show pilosity, and the association test by chi-square indicated that for plants present in "capoeira" there are a greater folivory for those that do not present trichomes on its leaf limb.&nbsp

Food preference of insects in capoeira area in east of state of Maranhão, Brazil

In the relation between plants and herbivores, both organisms developed along their evolutionary histories mediating mechanisms for these relationships. Considering that the present work had the objective to evaluate the herbivory food preference of plants by insects in an area of capoeira phytophysiognomy and the hypothesis tested was that insects prefer plants with lower leaf tenacity. The study was carried out in Caxias, Maranhão, Brazil, in November 2016, in which 600 leaves were analyzed with half of tenacious leaves and one of soft leaves. The chi-square test indicated an association between the variables tested pointing an occurrence of herbivory preference for plants with tenacious leaves