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The actions required for biodiversity conservation depend on species responses to habitat loss, which may be either neutral, linear, or non-linear. Here, we tested how taxonomic, functional, and phylogenetic diversity of aquatic insects, dragonflies, frogs, and terrestrial mammals, as well as their species composition respond to forest cover loss. We hypothesized that taxonomic, functional, and phylogenetic diversity would respond nonlinearly (thresholds) to forest cover loss. Our findings do not support the current idea that a single threshold value of forest cover loss is applicable across tropical regions, or that some biodiversity facets are consistently more sensitive than others across different taxa. Species compositional responses to forest cover loss showed general patterns with thresholds between 30-50%. These results highlight the importance to consider multiple biodiversity facets when assessing the effects of forest cover loss on biological communities.

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF), Fundacao de Amparo a Pesquisa do Estado do Amazonas (FAPEAM), BIODIVERSA/FAPEAM, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ), Bundesministerium fuer Bildung und Forschung, Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), FAPEAM-Program POSGRAD, Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG), INPA/MCTI 465540/2014-7, Leibniz Competition 0621187/2017, Leibniz-Gemeinschaft R20F0002, Instituto Nacional de Pesquisas da Amazpnia, unidade de~pesquisa Ministerio da Ciencia, Tecnologia e Inovacoes (INPA/MCTI) 403758/2021-1, Programa Peixe Vivo of the Companhia Energetica de Minas Gerais 033W034A, Royal Society of New Zealand, Tertiary Education Commission, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Foundation for Science and Technology, Associate LaboratoryARNET J45/2018, CEEC

Latin America’s tremendous socio-cultural and biological diversity has evolved along tightly intertwined, far-reaching river networks. Decisions taken by any one country, may have strong impacts on the regional and even global biodiversity conservation agenda, such as the Convention on Biological Diversity. Here we comment on four perspectives complementing actions suggested by Azevedo-Santos et al. (2021) in their Commentary “Conservation of Brazilian freshwater biodiversity: Thinking about the next 10 years and beyond”. This contribution aims at attaining an effective conservation of freshwater biodiversity in Latin America, particularly in the context of the ongoing negotiations on the Global Biodiversity Framework. Our suggestions put forward cross-border perspectives, urging governments to engage in actions that consider the reality of and threats to transnational ecosystems such as many river basins of Latin America and elsewhere.

Ecosystem services do not exist independently from human perceptions and recognition. They are socially, culturally, economically, and environmentally scale- and context-dependent. Socio-cultural services tend to be difficult to evaluate and invisible to policymakers and conservation practitioners. Based on six years’ qualitative analysis of a floodplain fishery in the Pantanal wetland, Brazil, we bring an in-depth understanding of the socio-cultural ecosystem services in the region. We show that the inter- and intra-annual ecosystem dynamics variations in the flood pulse are closely associated with local people's governance structure, identity, and cosmological histories. All of them, to some extent, capture some of the unpredictable changes in the Pantanal. Our study uncovers part of the complex and rich social-cultural ecosystem service created from the interaction between local people and the ecosystem in which they are embedded. We also present the threats faced by these services in the face of current development projects in the Pantanal, such as the Waterway and Hydrometric Dams. We argue that the predicted outcome may jeopardize not only the social-cultural services in the Pantanal, but also the local people themselves and the environment that they are currently protecting.

Serious concerns have arisen regarding urbanization processes in western Amazônia, which result in the creation of artificial habitats, promoting the colonization of malaria vectors. We used structural equation modelling to investigate direct and indirect effects of forest cover on larval habitats and anopheline assemblages in different seasons. We found 3474 larvae in the dry season and 6603 in the rainy season, totalling ten species and confirming the presence of malaria vectors across all sites. Forest cover had direct and indirect (through limnological variables) effects on the composition of larval anopheline assemblages in the rainy season. However, during the dry season, forest cover directly affected larval distribution and habitat variables (with no indirect affects). Additionally, artificial larval habitats promote ideal conditions for malaria vectors in Amazonia, mainly during the rainy season, with positive consequences for anopheline assemblages. Therefore, the application of integrated management can be carried out during both seasons. However, we suggest that the dry season is the optimal time because larval habitats are more limited, smaller in volume and more accessible for applying vector control techniques.

Climate change is a matter of worldwide concern with severe predicted impacts on biodiversity. Here, we analysed the potential impacts of current and future climates on aquatic true bugs (Heteroptera) in relation to their distribution patterns and ecological preferences (based on a database generated from existing literature references and field collections). We considered the traits as ‘species thermal range’ and ‘emergence period’ to evaluate the future climate change impacts on the distributions of aquatic true bugs in the riverine regions of a tropical biodiversity hotspot, the Western Ghats of India. We used Species Distribution Models (SDMs) to evaluate the potential impacts of climate change on the distributions of aquatic true bugs. We modelled the distributions of twenty-six species of aquatic true bugs using different modelling tools through a carefully examined set of occurrence records to generate potential present distributions and to project these distributions into future scenarios of climate change. We observed increasing/decreasing range sizes of the species in the current and future scenarios. We found losses and increases of species' ranges in some regions, but not much variation in species richness. Similarly, no significant effect was observed in the distribution ranges for species with different duration of emergence period and thermal range in current and future climatic scenarios. Losses and gains in species richness would be concentrated in the mountainous area of the Western Ghats, whereas loss of species and the bigger difference between current and future richness will occur in the adjacent lowlands and towards central regions, including the network of protected areas of the Western Ghats. These areas are critical to buffer regional species loss in the future. Given the importance of aquatic true bugs as bioindicators and biological control agents, monitoring their range shifts should be routinely addressed in the conservation contexts of the Western Ghats.

International audience; Context: Determining the appropriate scale at which to study species’ interactions with their environment is a great challenge.Objective: We investigated the spatial extent at which landscape structure affects the occurrence of four species of terrestrial mammalian herbivores in the Brazilian savannas and examined whether those scales could be explained by species ecological traits and how forest habitat was operationally defined.Methods: Using maps of forest cover, camera trapping and occupancy modelling, we determined the relations between three landscape metrics (percentage of forest cover, patch density and edge density) and the occurrence of four species. To determine the optimal scale of effect for each species, we computed landscape metrics at different spatial extents (from 0.5 to 10 km radius) from camera trap locations and for three forest maps, each using different operational definitions of a forest pixel: minimum of tree cover of 25, 50 or 75%.Results: The occupancy models revealed scales of effect of 0.5 to 2 km with the scale of effect being similar among three of the species. However, the probability of a scale of effect being detected depended upon how forest is operationally defined, being greater when forest was defined with greater tree cover, particularly for forest-specialist species.Conclusions: Besides biological traits, the way habitat is operationally defined shapes our ability to detect the scale of effects. Thus, it is necessary not to adopt a multi-scale approach, but also to use multiple operational definitions of habitat, considering particularities of how each species interact with their environment.

Human impacts on the Earth’s biosphere are driving the global biodiversity crisis. Governments are preparing to agree on a set of actions intended to halt the loss of biodiversity and put it on a path to recovery by 2050. We provide evidence that the proposed actions can bend the curve for biodiversity, but only if these actions are implemented urgently and in an integrated manner.

Made available in DSpace on 2020-12-12T02:42:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Protecting riparian vegetation around streams is vital in reducing the detrimental effects of environmental change on freshwater ecosystems and in maintaining aquatic biodiversity. Thus, identifying ecological thresholds is useful for defining regulatory limits and for guiding the management of riparian zones towards the conservation of freshwater biota. Using nationwide data on fish and invertebrates occurring in small Brazilian streams, we estimated thresholds of native vegetation loss in which there are abrupt changes in the occurrence and abundance of freshwater bioindicators and tested whether there are congruent responses among different biomes, biological groups and riparian buffer sizes. Mean thresholds of native vegetation cover loss varied widely among biomes, buffer sizes and biological groups: ranging from 0.5% to 77.4% for fish, from 2.9% to 37.0% for aquatic invertebrates and from 3.8% to 43.2% for a subset of aquatic invertebrates. Confidence intervals for thresholds were wide, but the minimum values of these intervals were lower for the smaller riparian buffers (50 and 100 m) than larger ones (200 and 500 m), indicating that land use should be kept away from the streams. Also, thresholds occurred at a lower percentage of riparian vegetation loss in the smaller buffers, and were critically lower for invertebrates: reducing only 6.5% of native vegetation cover within a 50-m riparian buffer is enough to cross thresholds for invertebrates. Synthesis and applications. The high variability in biodiversity responses to loss of native riparian vegetation suggests caution in the use of a single riparian width for conservation actions or policy definitions nationwide. The most sensitive bioindicators can be used as early warning signals of abrupt changes in freshwater biodiversity. In practice, maintaining at least 50-m wide riparian reserves on each side of streams would be more effective to protect freshwater biodiversity in Brazil. However, incentives and conservation strategies to protect even wider riparian reserves (~100 m) and also taking into consideration the regional context will promote a greater benefit. This information should be used to set conservation goals and to create complementary mechanisms and policies to protect wider riparian reserves than those currently required by the federal law. Departamento de Ecologia Universidade Federal de Goiás (UFG) Instituto de Biociências Universidade Estadual Paulista (UNESP) Instituto Nacional de Pesquisas da Amazônia (INPA) Departamento de Biodiversidade Universidade Federal do Paraná (UFPR) Programa de Pós-Graduação em Tecnologias para o Desenvolvimento Sustentável Universidade Federal de São João Del Rei (UFSJ) Instituto Amazônico de Agriculturas Familiares Universidade Federal do Pará (UFPA) Laboratório de Hidrologia Florestal Escola Superior de Agricultura Luiz de Queiroz Universidade de São Paulo (USP) Instituto de Ciências Biológicas Universidade Federal do Pará (UFPA) Programa de Pós-Graduação em Biologia UNISINOS Departamento de Genética Ecologia e Evolução Instituto de Ciências Biológicas Universidade Federal de Minas Gerais (UFMG) Instituto de Geociências Departamento de Geografia Universidade Federal de Minas Gerais (UFMG) Laboratório de Ecologia e Conservação de Ecossistemas Aquáticos Universidade Federal de Mato Grosso (UFMT) Centro de Engenharias e Ciências Exatas Universidade Estadual do Oeste do Paraná (UNIOESTE) Laboratório de Sistemática e Ecologia de Insetos Departamento de Ciências Agrárias e Biológicas Universidade Federal do Espírito Santo (UFES) Campus de Ciências Exatas e Tecnológicas Universidade Estadual de Goiás (UEG) Departamento de Ecologia Universidade Federal do Rio Grande do Sul (UFRGS) Laboratório de Organismos Aquáticos (LOA) Departamento de Ciências Biológicas Universidade Estadual de Santa Cruz (UESC) Programa de Pós-Graduação em Ecologia e Conservação Universidade Federal do Mato Grosso do Sul (UFMS) Departamento de Entomologia Museu de Entomologia Universidade Federal de Viçosa (UFV) Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista (UNESP) Laboratório de Ecologia e Conservação Departamento de Engenharia Ambiental Universidade Federal do Paraná (UFPR) Programa de Pós Graduação em Biodiversidade (PPGBC) Universidade Federal do Pará (UFPA) Laboratório de Inteligência Artificial Eletrônica de Potência e Sistemas Digitais Universidade Federal de Mato Grosso do Sul (UFMS) Centro Universitário FG (UNIFG) Instituto Federal de Educação Ciencia e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS) Universidade Federal de Alfenas (UNIFAL) Departamento de Biologia Universidade Federal de Lavras (UFLA) Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais (PEA) Universidade Estadual de Maringá (UEM) Instituto de Ciências e Tecnologia das Águas Universidade Federal do Oeste do Pará (UFOPA) Museu de História Natural Capão da Imbuia (MHNCI) Instituto Nacional de Pesquisa do Pantanal (INPP) Campus Avançado do Museu Paraense Emílio Goeldi (MPEG) Laboratório de Ecologia Centro de Estudos em Recursos Naturais (CERNA) Universidade Estadual de Mato Grosso do Sul (UEMS) Centre for Tropical Biodiversity and Climate Change and Centre for Tropical Environmental and Sustainability Studies College of Marine & Environmental Sciences James Cook University Instituto de Biociências Universidade Estadual Paulista (UNESP) Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista (UNESP) CNPq: 465610/2014-5

1. Motivated by recent global initiatives for biodiversity conservation and restoration, this article reviews the gaps in our understanding of, and the challenges facing, freshwater macroinvertebrate biodiversity and conservation in tropical regions. 2. This study revealed a lack of adequate taxonomic, phylogenetic, and ecological information for most macroinvertebrate groups, and consequently there are large-scale knowledge gaps regarding the response of macroinvertebrate diversity to potential climate change and other human impacts in tropical regions. 3. We propose ideas to reduce the impact of key drivers of declines in macroinvertebrate biodiversity, including habitat degradation and loss, hydrological alteration, overexploitation, invasive species, pollution, and the multiple impacts of climate change. 4. The review also provides recommendations to enhance conservation planning in these systems (as well as providing clear management plans at local, regional, and national levels), integrated catchment management, the formulation of regulatory measures, the understanding of the determinants of macroinvertebrate diversity across multiple scales and taxonomic groups, and the collaboration between researchers and conservation professionals. 5. It is suggested that the integrated use of macroinvertebrate biodiversity information in biomonitoring can improve ecosystem management. This goal can be facilitated in part by conservation psychology, marketing, and the use of the media and the Internet.

Veredas (palm swamps) play a critical role in maintaining the hydrological system and they are considered the cradle of the waters of the Brazilian Cerrado. Currently, veredas are suffering intense human pressure due to the conversion of native landscapes for other land uses as agriculture, pasture and urban environments. Few studies have evaluated the biodiversity of veredas and the current effects of human impact, especially on aquatic communities. Dragonflies and damselflies (Odonata) have excelled as bioindicators of environmental quality and they are increasingly used in environmental monitoring programs. In this study, we evaluate whether loss of riparian vegetation around the vereda areas alters the communities of Odonata and whether the species can be considered bioindicators of these environmental conditions. Our hypothesis is that eco-physiological and behavioral characteristics, such as thermoregulation capacity and oviposition behavior, influence the persistence of species in communities in natural or altered environments. We sampled 25 veredas and classified them into two groups, namely “preserved riparian vegetation” (VRP), when the riparian vegetation surrounding the sampled stretch was 30 meters or more, and “altered riparian vegetation” (VRA), when the vegetation extended for less than 30 meters from at least one of the banks. Our results showed that the composition of the communities in areas classified as VRP was more similar to each other and different from the communities found in the areas classified as VRA. Of the 52 species observed, 11 species responded as indicators for preserved or altered riparian vegetation. Of these species, four were indicative of areas with preserved riparian vegetation and seven were indicative of veredas with altered riparian vegetation. Our results show that the composition of dragonflies and damselflies, and some taxa in particular may be potential indicators of the condition of veredas, and may, therefore, be included in vereda monitoring programs in Central-Western Brazil.

The study of variation of species composition among sites is key to understanding community ecology, but few studies have assessed beta diversity patterns in highly dynamic stream networks in the Neotropical region. We assessed aquatic insect patterns of local contribution to beta diversity (LCBD) and species contribution to beta diversity (SCDB) in a Neotropical drainage network composed of both perennial and intermittent streams in a dry period. We evaluated if environmental and/or spatial predictors drive patterns of LCBD. We sampled aquatic insects in 12 intermittent headwater streams and 34 perennial streams. The intermittent compared to perennial streams had higher LCBDs and lower richness. The pure environmental component significantly explained 19% of the variation of LCBD, while the pure spatial components were not significant. Forty-six taxa contributed to beta diversity above the mean of the 199 taxa. We detected the association of oxygen tolerant and good dispersal ability taxa to intermittent streams and species riffle-adapted taxa as indicators of perennial streams. We showed a disproportional contribution of intermittent streams to the regional species pool. In summary, we demonstrated that when streams dry out, compositional uniqueness may increase during the dry period making them critical to conservation planning of dynamic stream networks.

The rate of deforestation and the number of large wildfires are increasing in the Amazon. Illegal loggers, miners, ranchers, and farmers all have contributed to this increase. Their activities have dramatic consequences for biodiversity, ecological services, and people. In this study, we estimated the number of jaguars affected by deforestation. We focused on the Brazilian Amazon from August 2016 to December 2019. Further, we analyzed the effects of socio‐geographic determinants of deforestation and state policies. To do so, we used deforestation data from DETER‐B satellite system. The number of jaguars within each deforested area was pulled from a previous study, which provided jaguar abundances for jaguar entire range. We assumed all jaguars within a deforested area were affected (displaced or killed). To determine the underlying causes of jaguar loss, we regressed the number of jaguars lost per state and year against the proportion of total forest area within reserves, distance to forest border, and monetary efficiency in cattle production. We estimate a total of 1,422 jaguars have been displaced/killed in recent years (2016: 488, 2017: 360, 2018: 268, 2019: 354). Only the proportion of protected area had an effect in reducing jaguar deforestation. We discuss how our work could result in near real‐time monitoring of jaguar displacement and how policies such as wood certification, more efficient cattle production, and centralizing governance may be solutions.

Deforestation is a major threat globally, but especially in tropical regions because they are biodiversity strongholds and carbon storehouses. Some studies have reported changes in species richness and composition in lotic ecosystems with increased forest-loss in their catchment, presumably resulting from the replacement of sensitive taxa by more resistant or tolerant taxa. Also, sensitive taxa respond to deforestation in a non-linear manner and fish and macroinvertebrates have different sensitivities to landscape pressures. Therefore, it is useful to determine the effects of forest-loss on widespread sensitive or threshold taxa in aquatic ecosystems. We used Threshold Indicator Taxa Analysis (TITAN) to assess forest-loss and land use history impacts in 92 eastern Amazonian stream sites. We determined TITAN peak-change thresholds for fish at 1% and 6% of forest-loss at total-catchment and local-riparian spatial extents, respectively, and at 2% and 40% of land-use intensity change at total-catchment and local-riparian spatial extents, respectively. For macroinvertebrates, TITAN peak-change thresholds were 1% and 11% of forest loss at total-catchment and local-riparian spatial extents, respectively, and at 3% of land-use intensity change for both total-catchment and local-riparian spatial extents. Because of these thresholds, inherent ecoregional variability and key literature, we have three major recommendations. 1) Logging should be prohibited in riparian reserves that are at least 100-m wide on each side of headwater streams and in a network of catchments across all biomes and as many landscape types as possible. 2) An ecologically and statistically rigorous monitoring program with standard methods should be implemented to assess and regulate land uses better. 3) Conservation planning areas should consider aquatic biota as well as terrestrial biota.

Herbivory is ubiquitous. Despite being a potential driver of plant distribution and performance, herbivory remains largely undocumented. Some early attempts have been made to review, globally, how much leaf area is removed through insect feeding. Kozlov et al., in one of the most comprehensive reviews regarding global patterns of herbivory, have compiled published studies regarding foliar removal and sampled data on global herbivory levels using a standardized protocol. However, in the review by Kozlov et al., only 15 sampling sites, comprising 33 plant species, were evaluated in tropical areas around the globe. In Brazil, which ranks first in terms of plant biodiversity, with a total of 46,097 species, almost half (43%) being endemic, a single data point was sampled, covering only two plant species. In an attempt to increase knowledge regarding herbivory in tropical plant species and to provide the raw data needed to test general hypotheses related to plant–herbivore interactions across large spatial scales, we proposed a joint, collaborative network to evaluate tropical herbivory. This network allowed us to update and expand the data on insect herbivory in tropical and temperate plant species. Our data set, collected with a standardized protocol, covers 45 sampling sites from nine countries and includes leaf herbivory measurements of 57,239 leaves from 209 species of vascular plants belonging to 65 families from tropical and temperate regions. They expand previous data sets by including a total of 32 sampling sites from tropical areas around the globe, comprising 152 species, 146 of them being sampled in Brazil. For temperate areas, it includes 13 sampling sites, comprising 59 species. Thus, when compared to the most recent comprehensive review of insect herbivory (Kozlov et al.), our data set has increased the base of available data for the tropical plants more than 460% (from 33 to 152 species) and the Brazilian sampling was increased 7,300% (from 2 to 146 species). Data on precise levels of herbivory are presented for more than 57,000 leaves worldwide. There are no copyright restrictions. Please cite this paper when using the current data in publications; the authors request to be informed how the data is used in the publications.

Though many studies have demonstrated top-down control by macroconsumers on benthic communities and ecosystem processes in tropical streams, few have simultaneously addressed such effects across a gradient of riparian vegetation loss. Here, we investigated if potential top-down effects induced by macroconsumers interact with native vegetation changes of tropical karst streams in Brazil. We experimentally excluded macroconsumers (e.g., fish and shrimp) from benthic habitats of seven streams with a range of forest cover from 20% to 100% and examined the effects on benthic invertebrate and periphyton communities. Across sites, the absence of macroconsumers had no effects on mean chlorophyll-a concentrations, total dry mass or abundance of benthic invertebrates. However, the periphyton community significantly differed between control and treatment replicates. Overall, experimental exclusion of macroconsumers resulted in weak or negligible effect on benthic communities, which contrasts a significant proportion of related literature conducted elsewhere. Such top-down effects have been poorly studied in tropical karstic streams to date.

The presently reported study provides the length–weight relations (LWR) for 23 species from headwater streams of the Bodoquena Plateau, which is located on the southern border of the Brazilian Pantanal. The following species were studied Steindachnerina brevipinna (Eigenmann et Eigenmann, 1889); Characidium zebra Eigenmann, 1909; Bryconops melanurus (Bloch, 1794); Aphyocharax dentatus Eigenmann et Kennedy, 1903; Astyanax lacustris Lütken, 1875; Astyanax lineatus (Perugia, 1891); Brachychalcinus retrospina Boulenger, 1892; Creagrutus meridionalis Vari et Harold, 2001; Hemigrammus lunatus Durbin, 1918; Hyphessobrycon eques (Steindachner, 1882); Hyphessobrycon luetkeni (Boulenger, 1887); Jupiaba acanthogaster (Eigenmann, 1911); Moenkhausia bonita Benine, Castro et Sabino, 2004; Odontostilbe pequira (Steindachner, 1882); Piabarchus analis (Eigenmann, 1914); Serrapinus calliurus (Boulenger, 1900); Hoplerythrinus unitaeniatus (Spix et Agassiz, 1829); Hypostomus basilisko Tencatt, Zawadzki et Froelich, 2014; Otocinclus vittatus Regan, 1904; Rineloricaria parva (Boulenger, 1895); Cichlasoma dimerus (Heckel, 1840); Crenicichla lepidota Heckel, 1840; Poecilia reticulata Peters, 1859. Specimens were collected in February and October of 2016. This study represents the first LWR data for 13 species and the maximum standard length for Astyanax lacustris and Moenkhausia bonita.

Identifying the threshold of habitat cover beyond which species of birds are locally lost is useful for understanding the biological consequences of landscape changes. However, there is little consensus regarding the impact of landscape changes on the likelihood of species extinctions. We conducted a literature search using Scopus and ISI Web of Knowledge databases to identify studies where bird species were used to estimate threshold responses to landscape changes. We obtained a list of 31 papers published from 1994 to 2018, with 24 studies conducted at temperate latitudes and seven in tropical regions. Nineteen studies were based on species‐level assessments, and investigators used a variety of response variables such as probability of detection and occurrence to detect threshold responses. Eight studies were based on communities, and species richness and abundance were primarily used to detect threshold responses. Four studies included both communities and species‐level assessments. Methods used to identify threshold responses varied among studies, but most relied on either regression models to visually identify values from graphs or piecewise regression to estimate a specific threshold value. Although the limited number of studies and their variety of approaches and methods prevented a formal meta‐analysis, we found that mean threshold responses in studies that reported either a range or a single threshold value were 27.9% at temperate latitudes (range = 1.3–90%; N = 11) and 33.6% at tropical latitudes (range = 20–50%; N = 7). Considering only studies where single threshold values were reported, the mean habitat cover threshold was 11% for studies conducted at temperate latitudes (N = 3) and 29.5% for studies in the tropics (N = 4). These crude estimates suggest that tropical species might be more susceptible to habitat loss than temperate species. Although application of the threshold concept is still controversial, the number of studies using this approach is increasing because the results of such studies may have direct application to conservation strategies and restoration of landscapes for bird conservation.

An efficient indicator group should fulfill operational and performance-related criteria, including reasonable taxonomic knowledge, costs, response to environmental changes and strong proxy-capacity for biodiversity groups. However, in the real world many trade-offs are involved in the selection of an indicator group, and a single group rarely satisfies all criteria. We investigated cross-taxon congruence of assemblage composition patterns using both quantitative and qualitative data between adult dragonflies and aquatic insects (midges, Ephemeroptera-Plecoptera-Trichoptera (EPT), beetles and entire aquatic insects assemblage). Also, we tested whether environmental and spatial variables were important drivers for cross-taxon congruence. Finally, we developed a set of guiding criteria that avoid arbitrariness in the selection of the best indicator group. We sampled adult dragonflies and aquatic insects in 41 streams and rivers along a riparian vegetation loss gradient in a Neotropical riverine network. We used Procrustes analyses to verify surrogacy between groups and the association of each group with environmental and spatial predictors. The criteria used involves both operational and performance aspects to select an indicator group. Our results showed that adult dragonflies were weakly congruent with the entire aquatic insects assemblage and aquatic insect subgroups were moderate (beetles) to strongly (EPT and midges) congruent with the entire assemblage. Comparisons between EPT, midges and beetles were also weakly congruent, with the exception of midges-EPT. The association between assemblage patterns and overall environmental predictors was significant for all groups, while with spatial patterns, only midges and entire assemblage showed significant results. Numerical resolution slightly improved the congruence results. Incidence data could be used instead of abundance, due to higher congruence values compared to abundance data. Based on cost-benefit, EPT was selected as the best indicator group for monitoring the effects of riparian vegetation loss on aquatic biodiversity, and its use could be viable in biomonitoring programs.

As oil palm plantations continue to expand in Neotropical regions, identifying critical transitions in land use, at which animal communities can be drastically altered, is crucial for conservation planning. Here, we investigated potential unexpected change points (thresholds) in the response of terrestrial mammal's richness and community composition to increasing oil palm cover in the Llanos region of Colombia. We deployed camera traps to detect species across 56 sites (landscapes of ~220 ha each) and used segmented regression and Threshold Indicator Taxa Analysis (TITAN) for the identification of these thresholds. We found a negative linear relationship between the proportion of oil palm and species richness, but no evidence of a threshold. In contrast, we found strong signs of a community threshold when oil palm cover in the study area reached 45–75%, at which mammalian species composition (taxon-specific changes of abundance and occurrence frequency) drastically changed. When species were assessed individually, a significant threshold relationship to oil palm cover was found to occur in 10 of the 15 examined species, with four (squirrel, agouti, spiny rat, common opossum) having a negative drastic change at approximately 45% oil palm cover. Five species showed no evidence for any critical threshold (giant and lesser anteater, jaguarondi, white-tailed deer and raccoon). We used the community threshold identified above as a baseline to evaluate the conservation status of the four oil palm production zones in Colombia. We found that approximately 41% of the total area covered by oil palm in Colombia has crossed the identified threshold of 45–75%, suggesting urgent need for forest restoration to increase its extent if a collapse of their resident mammal communities is to be avoided. These findings provide guidance for the design of sustainable landscapes within production areas in Colombia to promote the conservation of terrestrial mammals.

The necessity to create national to global-scale biodiversity monitoring systems as part of assessing progress toward biodiversity agendas presents a challenge for signatory countries. This is a brief review of ongoing Brazilian national initiatives that would allow the construction of a general biomonitoring network scheme in protected areas; with additional focus on linking independent monitoring schemes. We discuss some key aspects needed to include monitoring schemes under a single framework that will lead to better evaluation of pressure–state–response indicators for managing biodiversity at several scales; and we point out the potential of embracing citizen science and participatory monitoring to quantify some aspects within those schemes. © 2018 Associação Brasileira de Ciência Ecológica e Conservação