We assessed the magnitude, composition, and spatial and temporal patterns of road mortality of native vertebrates on two highways in southern Brazil from 18 January 2003 to 26 January 2004. The highways cross remnants of the Atlantic Rainforest, a global biodiversity hotspot, and differ in vehicle traffic and surrounding landscape. We compared the road-kill magnitude and composition of birds, mammals, and reptiles between roads and seasons. We used a modified K statistic to depict the spatial patterns of roadkills of these groups and tested the association between vehicle traffic and road mortality through linear regression. We recorded 869 kills of 92 species. The two roads differed regarding the abundance and composition of roadkills. Reptile road mortality was higher in summer than winter, but all other groups did not show significant difference in the magnitude of mortality between seasons. The composition of killed assemblages differed significantly for some of the taxonomic groups among seasons. We found only one positive association between roadkills and vehicle traffic (reptiles on one of the roads), suggesting that vehicle flow does not explain the road-kill temporal variation on these roads. Total vertebrate, bird, and mammal roadkills showed significant spatial aggregations possibly due to variation in vehicle traffic, highway design, and local landscape condition and arrangement. With expected expansion of the road network, mitigation measures for multi-species assemblages should include habitat protection, soil use regulation, road crossing structures, speed reducers, and campaigns to raise people's awareness about road impacts on wildlife.

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Unmanned aerial systems (UAS) are emerging as an accessible and versatile tool for ecologists, promising to revolutionize the way abundance and distribution data are obtained in wildlife studies. Establishment of UAS as an efficient and reliable tool demands understanding how detection errors influence UAS‐derived counts and possible solutions to address them. We describe two types of false‐negative errors (availability and perception errors) and two types of false‐positive errors (misidentification and double count) that may bias abundance estimates from UAS surveys. Then, we discuss available methods to address detection errors in UAS surveys and point out challenges for future developments. We present hierarchical models as an integrative framework to account for multiple detection errors and datasets in UAS abundance modelling. Methods to address detection errors in UAS surveys depend on how data are collected (flight plan, images processing, and reviewing procedure). Conventional aerial surveys literature offers a set of solutions, especially to deal with false‐negative errors. Available auxiliary information (such as ground counts and telemetry data) facilitates estimating detection errors, although the versatility of UAS permits exploring novel approaches. Solutions involve planning separated strip transects, temporally replicating flights, carrying out counts in orthomosaics, and multiple observer protocol. When automatic image review is used, subsample manual reviewing, trial experiments, and semiautomated procedures might deal with algorithm errors. UAS surveys need to be consciously planned, thinking on what kind of errors can significantly affect counts and the use of raw counts and indices should be avoided. Approaches that formally account for false positives are needed, particularly for double counts. Hierarchical modelling (especially N‐mixture models) offers a fruitful framework to explore and combine solutions, integrating multiple datasets and accommodating different detection errors.

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Abstract:The effects of habitat fragmentation and deforestation are exacerbated by some elements, such as roads and power lines, which may become filters or barriers to wildlife movements. In order to mitigate mortality and restore connectivity, wildlife passages are being constructed as linear corridors. The installation of these mitigation measures must be followed by systematic monitoring, in order to evaluate their use and effectiveness, to assist in their management, and to convince stakeholders of their value. In this paper we present the results of a monitoring study of the use of rope overpasses developed near a protected area in Porto Alegre, southern Brazil. The canopy bridges were installed by the Urban Monkeys Program in places where electric hazards and road-kills of brown howler monkeys (Alouatta guariba clamitans Cabrera, 1940) were recorded. Camera traps were installed at each bridge, and local people were selected and trained to monitor overpass use over 15 months, from August 2008 to October 2009. Three species were recorded using canopy bridges: brown howler monkey (Alouatta guariba clamitans Cabrera, 1940), white-eared opossum (Didelphis albiventris Lund, 1840) and porcupine (Sphiggurus villosus Cuvier, 1823). Rope bridges with the highest number of species recorded had more forest cover and lower urban area around them than overpasses little used. Our results indicate that overpasses, in Porto Alegre, work as a linear corridor between forest remnants, although the outcomes for individual survival, group persistence, population demography or gene flow have not been measured. Furthermore, canopy bridges may be important to mitigate the impact of roads and power lines on wildlife, but electric cables also need to be completely isolated when present, to warrant animals' physical integrity. Resumo: Os efeitos do desmatamento e da fragmentação de hábitats são exacerbados por elementos como rodovias e redes elétricas, que podem atuar como filtros ou barreiras aos movimentos da vida silvestre. Com o objetivo de mitigar a mortalidade e restaurar a conectividade, passagens de fauna têm sido construídas como corredores lineares. A instalação dessas estruturas deve ser seguida de monitoramento sistemático, visando à avaliação de seu uso e efetividade e a geração de informações para seu manejo e para convencer os tomadores de decisão sobre seu valor. Neste artigo, apresentamos os resultados do monitoramento do uso de seis pontes de corda, realizado durante 15 meses, entre agosto de 2008 e outubro de 2009, nas imediações da Reserva Biológica do Lami José Lutzenberger, em Porto Alegre, Brasil. As pontes de dossel foram instaladas pelo Núcleo de Extensão Macacos Urbanos em locais com registros de atropelamentos e choques elétricos de bugios-ruivos (Alouatta guariba clamitans Cabrera, 1940). Instalamos armadilhas fotográficas em cada ponte e selecionamos moradores locais para registrarem seu uso. Três espécies foram registradas usando as pontes de corda: o bugio-ruivo (Alouatta guariba clamitans Cabrera, 194...

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The evaluation of road-kill spatial patterns is an important tool to identify the priority of locations for mitigation measures aiming to reduce wildlife mortality on roads. Single-target or multi-species approaches are usually adopted on the implementation of such measures, although their success must be assessed. We aim to test if road-kill hotspots are coincident among different vertebrate groups. If this proves to be right, data on accidents from one group could be used to plan measures applicable to other groups. We identified hotspots using five different grouping criteria: vertebrate Classes (reptiles, birds or mammals), body size (large or small), species commonness (common or rare), type of locomotion (flying or non-flying), and time of activity (nocturnal/crepuscular or diurnal). We analyzed data from road-kill surveys on four roads in southern Brazil, each with at least one year of monitoring. We performed a modified Ripley's K-statistic to recognize scales of road-kill aggregation, and we carried out a hotspot analyses to identify the location of road-kill aggregations for each group described above on each road. To test for similarity in hotspot location among different groups we performed an association test using correlation as the resemblance measure. Hotspot analyses and association tests were done using different spatial scales to evaluate the effect of scales on similarities. Correlation results between groups presented low values at small scales although they had a tendency to increase with raising scales. Our results show that road-kill hotspots are different among groups, especially when analyzed on small scales. We suggest that, for a successful biodiversity approach to mitigation, one should first select general hotspots on large scales and then identify specific hotspots on small scales to implement specific measures. These findings are relevant in a context of existing road networks, where mitigation measures are being planned to reduce impact on wildlife.

This study evaluated the influence of vegetation structure on bird diversity, guilds, and the richness and composition of species in different successional stages of the subtropical Atlantic rain forest. Much of the land that was formerly agricultural in the Brazilian Atlantic rain forest region is now given over to secondary forests. The habitat structure of these successional forests vary and are influenced by time, historical use and local variables, all of which affect bird assemblies. Sampling of bird species was carried out through audio-visual point counts conducted in forests varying from six years after abandonment to old-growth areas. Forests in which the point counts were conducted were further classified into initial, intermediate and advanced stages according to 11 vegetation structural variables, through cluster analyses. The study found that bird richness and diversity were similar between initial and intermediate stages, but higher in advanced areas. Bird species composition differed between the initial and advanced stages, whereas the guild composition of initial forests differed in both intermediate and advanced stages. Late successional forests had more heterogeneous habitats, and some species and guilds were found only in this stage. However, bird diversity and species and guild composition were similar in intermediate and advanced forests, emphasizing the importance of successional forests for conservation efforts, especially when they are located near old-growth forests and conservation units. The recovery patterns of the successional forests studied indicate a great potential for the natural regeneration of the Atlantic rain forest, at least in areas where slash-and-burn agriculture was the previous landuse.Keywords: avifauna; habitat modification; secondary forests; vegetation structure. RESUMOEste estudo avaliou a influência da estrutura da vegetação sobre a diversidade, riqueza e composição de espécies e guildas de aves em florestas sucessionais na Mata Atlântica subtropical. Grande parte das áreas agrícolas que cobriam as regiões da Mata Atlântica são atualmente florestas secundárias, podendo variar em estrutura de habitat conforme o histórico de uso e variáveis locais, influenciando as assembleias de aves. A amostragem da avifauna foi realizada pelo método áudio-visual em pontos de escuta em florestas com seis anos de regeneração após o abandono a áreas antigas. Florestas em cada ponto de escuta foram posteriormente classificadas em estágios inicial, intermediário e avançado de acordo com 11 variáveis estruturais da vegetação, através da análise de agrupamento. A riqueza e diversidade de aves foram similares entre os estágios inicial e intermediário, mas maiores no estágio avançado. A composição de espécies diferiu somente entre os estágios inicial e avançado, enquanto a composição de guildas do estágio inicial diferiu dos estágios intermediário e avançado. Florestas tardias foram mais heterogêneas em termos de habitat, e algumas espécies de aves e guildas foram registradas so...