Karina Dias-Silva

A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazônia Sustentável, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.

The influence of habitat integrity and physical-chemical water variables on the structure of aquatic and semi-aquatic Heteroptera

This work aimed to assess the effect of certain physical-chemical variables and the Habitat Integrity Index (HII) have on an aquatic and semi-aquatic heteropteran community. We collected in five streams (from 1st to 4th order) that differed in habitat integrity, in order to test 1) whether heteropteran richness decreases with the Habitat Integrity Index; and 2) whether richness responds to alterations in water physical-chemical variables, since these influence community structure. In each stream, linear transects of 100 m were demarcated. A total of 1425 specimens from 10 families, 30 genera and 67 morphospecies were collected. Species richness was correlated with the Habitat Integrity Index (HII), showing a positive relationship only for Gerromorpha. This may be due to the fact that streams with greater integrity offer nearby marginal vegetation where prey and shelter can be easily found, representing optimal places for oviposition and hunting. Species adapted to such conditions are more sensitive to alterations in the physical structure of rivers. Significant differences in the composition of Heteroptera and studied infra-orders were also observed, which suggests that the anthropic disturbances over these sites have changed these insect communities. Our results indicate that the alteration in riparian areas can lead to significant changes in Heteroptera composition, even though species richness was not affected. The physical-chemical variables showed no influence on the distribution of species. This result suggests that the environment presented insufficient variation that could cause changes in the investigated community, which implies that factors other than those analyzed here may explain such variation. Three species Rhagovelia trailli (White, 1879), Rhagovelia sp. 4 and Tenagobia incerta (Lundblad, 1928) were considered to be indicators of pristine sites. The results indicate that aquatic and semi-aquatic Heteroptera and more specifically the sub-order Gerromorpha can be an important tool to assess environmental habitat integrity and enhance conservation actions of riparian forests.

Taxonomic and Numerical Resolutions of Nepomorpha (Insecta: Heteroptera) in Cerrado Streams

Transformations of natural landscapes and their biodiversity have become increasingly dramatic and intense, creating a demand for rapid and inexpensive methods to assess and monitor ecosystems, especially the most vulnerable ones, such as aquatic systems. The speed with which surveys can collect, identify, and describe ecological patterns is much slower than that of the loss of biodiversity. Thus, there is a tendency for higher-level taxonomic identification to be used, a practice that is justified by factors such as the cost-benefit ratio, and the lack of taxonomists and reliable information on species distributions and diversity. However, most of these studies do not evaluate the degree of representativeness obtained by different taxonomic resolutions. Given this demand, the present study aims to investigate the congruence between species-level and genus-level data for the infraorder Nepomorpha, based on taxonomic and numerical resolutions. We collected specimens of aquatic Nepomorpha from five streams of first to fourth order of magnitude in the Pindaíba River Basin in the Cerrado of the state of Mato Grosso, Brazil, totaling 20 sites. A principal coordinates analysis (PCoA) applied to the data indicated that species-level and genus-level abundances were relatively similar (>80% similarity), although this similarity was reduced when compared with the presence/absence of genera (R = 0.77). The presence/absence ordinations of species and genera were similar to those recorded for their abundances (R = 0.95 and R = 0.74, respectively). The results indicate that analyses at the genus level may be used instead of species, given a loss of information of 11 to 19%, although congruence is higher when using abundance data instead of presence/absence. This analysis confirms that the use of the genus level data is a safe shortcut for environmental monitoring studies, although this approach must be treated with caution when the objectives include conservation actions, and faunal complementarity and/or inventories.

The genus Paravelia Breddin, 1898 (Hemiptera: Heteroptera: Veliidae) in Brazil, with descriptions of eight new species

Eight new species of Paravelia Breddin, 1898 from Brazil are described and illustrated: P. amapaensis sp. nov. from Amapá State, P. bipunctata sp. nov. from Minas Gerais, Mato Grosso and Mato Grosso do Sul States, P. bilobata sp. nov. and P. polhemusi sp. nov. from Mato Grosso State, P. bahiana sp. nov. from Bahia State, P. lacrymosa sp. nov. from Minas Gerais State, P. micromaculata sp. nov. from Maranhão State, and P. ornata sp. nov. from Amazonas State. The genus is redescribed, with photos of the dorsal view for nineteen species: P. basalis (Spinola), P. biae Spangler, P. boliviana Breddin, P. bullialata Polhemus & Polhemus, P. capillata (Drake& Harris), P. capixaba Moreira, Nessimian & Rúdio, P. conata (Hungerford), P. dilatata Polhemus & Polhemus, P. foveata Polhemus & Polhemus, P. itatiayana (Drake), P. lanemeloi Moreira & Barbosa, P. manausana Polhemus & Polhemus, P. nieseri Moreira & Barbosa, P. platensis (Berg), P. recens (Drake & Harris), P. rotundanotata (Hungerford), P. spinifera Polhemus & Polhemus, P. splendoris (Drake & Harris) and P. williamsi (Hungerford). Three of these species are recorded for the first time from Brazil: P. platensis, P. spinifera and P. williamsi. Also, the macropterous forms of P. capixaba and P. dilatata are described. Lastly, an identification key to the 36 species of Paravelia recorded from Brazil and a checklist of described species are presented.

Gerromorpha (Hemiptera: Heteroptera) of eastern Mato Grosso State, Brazil: checklist, new records, and species distribution modeling

The infraorder Gerromorpha comprises semiaquatic bugs, most of which spend much of their lifetime on the water surface, between floating plants, or on the margins of water bodies. Based on literature and collections made on streams and lakes on municipalities of eastern Mato Grosso, Brazil, a list has been elaborated with 52 species, including several new records. Out of the recorded species, 26 belong to the family Veliidae, 20 to Gerridae, three to Hydrometridae, two to Mesoveliidae, and one to Hebridae. The modeling of the potential geographical distribution is also presented for the 20 species that have been recorded for the first time from the state.

Water quality of rural ponds in the extensive agricultural landscape of the Cerrado (Brazil)

The Brazilian Cerrado, one of the world’s 34 biodiversity hotspots, is today under increasing pressure from the intensification of agriculture, with the replacement of traditional extensive pastures by arable crops. Manmade ponds are currently widespread in rural areas of the Cerrado and provide many ecosystem services such as cattle watering, fish production, irrigation and erosion protection. As in other parts of the world, ponds are also likely to play a critical role in the conservation of freshwater biodiversity, although in the Cerrado there is still very little known about their biota. Good water quality, in particular the level of eutrophication, is a key factor in maintaining aquatic biodiversity at the regional scale. Therefore, we aimed here to assess the water quality of ponds in the Cerrado. We also assessed whether the main types of socioeconomic pond uses have an impact on their water quality. We focused on measures of primary production and conducted socioeconomic inquiries for 56 waterbodies in the Goiânia Cerrado region (GO, Brazil) at the beginning of the 2012 dry season. Overall, differences in water quality appeared to be linked to the type of pond use. The trophic level, as indicated by the chlorophyll concentration and conductivity, was greater in fish ponds and seemed to be related to management practices such as fish feeding and the type of water supply, in particular relatively low inflow volume. This contrasted with ponds used for cattle watering in extensive agricultural landscapes characterized by a low trophic level potentially beneficial for regional biodiversity. Good water quality in pasture ponds may be maintained by spring water inflow or heavy precipitation. Overall, the water quality of the Cerrado ponds was good compared with the same type of waterbodies in other regions of the world. These results highlight the high potential of the Cerrado ponds in extensive agricultural landscapes to provide an important habitat for aquatic biodiversity. Biodiversity inventories and assessments are now needed to increase our knowledge of these waterbodies and inform management activities at the local and regional scale.

Elements of metacommunity structure in Amazonian Zygoptera among streams under different spatial scales and environmental conditions

Abstract An important aspect of conservation is to understand the founding elements and characteristics of metacommunities in natural environments, and the consequences of anthropogenic disturbance on these patterns. In natural Amazonian environments, the interfluves of the major rivers play an important role in the formation of areas of endemism through the historical isolation of species and the speciation process. We evaluated elements of metacommunity structure for Zygoptera (Insecta: Odonata) sampled in 93 Amazonian streams distributed in two distinct biogeographic regions (areas of endemism). Of sampled streams, 43 were considered to have experienced negligible anthropogenic impacts, and 50 were considered impacted by anthropogenic activities. Our hypothesis was that preserved (“negligible impact”) streams would present a Clementsian pattern, forming clusters of distinct species, reflecting the biogeographic pattern of the two regions, and that anthropogenic streams would present random patterns of metacommunity, due to the loss of more sensitive species and dominance of more tolerant species, which have higher dispersal ability and environmental tolerance. In negligible impact streams, the Clementsian pattern reflected a strong biogeographic pattern, which we discuss considering the areas of endemism of Amazonian rivers. As for communities in human‐impacted streams, a biotic homogenization was evident, in which rare species were suppressed and the most common species had become hyper‐dominant. Understanding the mechanisms that trigger changes in metacommunities is an important issue for conservation, because they can help create mitigation measures for the impacts of anthropogenic activities on biological communities, and so should be expanded to studies using other taxonomic groups in both tropical and temperate systems, and, wherever possible, at multiple spatial scales.

Efeito de fatores abióticos sobre Brachymetra albinervis albinervis (Heteroptera: Gerridae)

Analisou-se a influencia de fatores abioticos, distribuicao longitudinal e temporal sobre a abundância de Brachymetra albinervis albinervis Amyot & Serville, 1843. Foram avaliados tres sitios de um riacho de Cerrado: nascente, intermediario e foz, mensalmente durante um ano (junho de 2011 a maio de 2012). As variaveis abioticas aferidas foram: oxigenio dissolvido, temperatura da agua, pH, condutividade eletrica, largura e profundidade do riacho. Em cada sitio, mensalmente coletou-se em transeccao de 100 m lineares. Foram coletados 111 especimes. A foz apresentou menor abundância quando comparada aos outros locais (F(2, 9) 13,721, p = 0,001). A abundância nao variou entre os periodos do ano (chuva, vazante, seca ou inicio da chuva). Assim, a alteracao na abundância de B. a. albinervisanalisada ao longo de um ano foi influenciada pelos trechos do corrego, e essa variacao foi atribuida a alteracoes ambientais no sitio foz que apresentou menor abundância e consequentemente e o que apresenta menor integridade ambiental. Esses resultados contribuem para o conhecimento ecologico dessa especie e discute sobre a mudanca da ocorrencia da especie em funcao da alteracao dos ambientes aquaticos.