Density and biomass estimates by removal for an amazonian crocodilian, paleosuchus palpebrosus

Direct counts of crocodilians are rarely feasible and it is difficult to meet the assumptions of mark-recapture methods for most species in most habitats. Catch-out experiments are also usually not logistically or morally justifiable because it would be necessary to destroy the habitat in order to be confident that most individuals had been captured. We took advantage of the draining and filling of a large area of flooded forest during the building of the Santo Antônio dam on the Madeira River to obtain accurate estimates of the density and biomass of Paleosuchus palpebrosus. The density, 28.4 non-hatchling individuals per km2 , is one of the highest reported for any crocodilian, except for species that are temporarily concentrated in small areas during dry-season drought. The biomass estimate of 63.15 kg∗km-2 is higher than that for most or even all mammalian carnivores in tropical forest. P. palpebrosus may be one of the World?s most abundant crocodilians. © 2016 Campos, Magnusson. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Mamiferos da Fazenda Nhumirim, sub-região de Nhecolándia, Pantanal do Mato Grosso do Sul : I - levantamento preliminar de espécies

Trabalho conduzido na Fazenda Nhumirim, Centro de Pesquisa Agropecuária do Pantanal, EMBRAPA, com auxílio da OEA - Organização dos Estados Americanos, através do CNPq, fornecido ao Dr. Cleber J.R. Alho (Conta nº 03-85-528-517-BR-1)The pantanal is one of the world's richest freshwater wetlands. The pantanal is located in the flood plain of the headwaters of the Paraguai river, covering 140,000km2. The habitats of the Pantanal are present in a complex mosaic. The major habitat types are: pockets of forests, called capão or cordilheira, seasonally flooded grasslands or campos, and permanent or temporary lagoons, called baías. The Pantanal harbors both rich and abundant mammal fauna. A survey was conducted at Fazenda Nhumirim, a research station run by the Centro de Pesquisa Agropecuária do Pantanal (CPAP) in Corumbá, a research branch of EMBRAPA. The Fazenda covers an area of 4,310 ha in the sub-region of Nhecolândia, appoximately 150km east of Corumbá, Mato Grosso do Sul. The area receives an average annual rainfall of 1,022mm, and has a mean monthly temperature that varies between 29.1ºC (January) and 22.0ºC (June). Four routes were followed between two times during ten days of each month. The survey routes were covered on horseback by between two and four observers. Each route was followed and equal number of times in the morning and in the afternoon, to eliminate bias related to the activity patterns of mammals. In order to evaluate relative abundance of nocturnal species, we also conducted a number of nocturnal censuses. These censuses were done by car; a high intensity searchlight was used to spot the animals. We also conducted a trap-mark-recapture survey of the small mammals at Fazenda Nhumirim. After the census period, we continued to collect observations on the occurrence of mammals at the Fazenda, noting wherever possible the kind of habitat in which the animals were observed. The survey identified a diversity of mammals at Fazenda Nhumirim: six orders, 14 families, 19 genera, and 20 species. Nasua nasua was the most frequently observed species during the diurnal census, accounting for 61.5 percent of all observations. Dusicyon (formely Cerdocyon) thous was the most frequently observed species on the nocturnal census (39.13%). The small mammal community of Fazenda Nhumirim is composed of seven species: one marsupial, four cricetine rodents and two echimyid rodents

Uso de mapas mentais nas representações perceptivas de alunos do ensino fundamental do município de Ilha Grande, Piauí, Brasil: o caso do jacaré (Caiman crocodilus)

O estudo da percepção pode contribuir de forma significativa para subsidiar propostas de conservação de espécies animais. Este estudo consistiu em verificar quais os tipos de relações perceptivas que os alunos do ensino fundamental do município de Ilha Grande (PI) possuem acerca do jacaré (Caiman crocodilus), visando contribuir para planos de educação ambiental. O método usado para a representação da percepção foi o emprego de mapas mentais. Os desenhos demonstraram a presença de elementos representativos da paisagem (landmarks) e a existência de ambiguidade em relação aos sentimentos dos alunos para com a figura do jacaré: sentimentos positivos (biofilia) e negativos (biofobia).The study of perception can contribute significantly to support proposals for animal species conservation. This study sought to find out what kinds of perceptive relationship the middle school student population from the city of Ilha Grande (PI) has about the caiman, aiming to provide background information to environmental education plans. Mental maps were used to represent each perception, and the drawings showed the presence of representative elements of the landscape (landmarks) and the existence of ambiguity in relation to the students' feelings about the figure of caiman: positive feelings (biophilia) and negative feelings (biophobia)

Forecasting seasonal peaks in roadkill patterns for improving road management

For several species, roadkill is not spatially aggregated on hotspots, having instead a more diffuse pattern along the roads. For such species, management measures such as road passages may be insufficient for effective mitigation, since a large part of the road crossings is likely to occur outside the influence of those structures. One complementary approach could be to implement temporary mitigation actions, such as traffic calming. This requires understanding when roadkill peaks may occur. We tested the feasibility of predicting seasonal peaks of roadkill using data from a 3-year systematic monitoring (78 surveys over ca. 960 km of roads) from eight non-flying vertebrate species from Mato Grosso do Sul, Brazil, with different body size and life history traits (ca. 6400 records from focal species). We modelled the time-series of the roadkill of these species at large scale (state level) using generalized additive mixed models (GAMMs). We used the data of the first 2 years as training datasets, and the information from the third year of surveys as testing datasets to evaluate the prediction performance of models. Overall, the models of species feed with a higher number of records were able to follow reasonably well the variations of roadkill over time, although they were not able to correctly predict the number of collisions. For species with fewer observations, the models presented a poorer goodness-of-fit and prediction ability. Our results suggest that, at least for those species with higher roadkill rates, it can be possible to forecast periods of higher probability of occurring hot-moments of mortality. Such models can provide valuable information to implement seasonal management actions.info:eu-repo/semantics/publishedVersio

Extension of the geographical distribution of Schneider’s dwarf Caiman, Paleosuchus trigonatus (Schneider, 1801) (Crocodylia: Alligatoridae), in the Amazon–cerrado transition, Brazil

We present new records of occurrence of Schneider’s Dwarf Caiman, Paleosuchus trigonatus and extend its geographical distribution. Eight individuals were caught in the following locations: Sangue River, in the municipality of Campo Novo dos Parecis, Claro River and Marapi River, in the municipality of São José do Rio Claro, and tributaries of the Juruena River, in the state of Mato Grosso, Brazil. These records extend the geographical distribution of the species nearly 500 km south of the limit given in published range maps. © Campos et al

Um modelo de crescimento de Paleosuchus trigonatus (Crocodylia: Alligatoridae) do Rio Negro prevê o crescimento de indivíduos do rio Xingu, Brasil

Patterns of growth of crocodilians vary geographically within the same species, so models developed in one area may not predict size-age relationships in others. We used recapture data for three females and six males of Paleosuchus trigonatus from the Belo Monte hydroelectric dam area on the Xingu River to validate a growth model developed on a tributary of the Rio Negro. Individuals were recaptured between two and 10 years after marking (2012–2022). The data indicate that the monomolecular (von Bertalanffy by length) model is adequate to model growth of intermediate size animals. Recapture of one female after eight years indicates that the Rio Negro model can be used to model growth with accuracy for individuals from the Xingu River.Os padrões de crescimento dos crocodilianos variam geograficamente dentro da mesma espécie, de modo que os modelos desenvolvidos em uma área não preveem relações tamanho-idade em outras. Usamos dados de recaptura de três fêmeas e seis machos de Paleosuchus trigonatus da área da hidrelétrica de Belo Monte no rio Xingu para validar um modelo de crescimento desenvolvido em um afluente do rio Negro. Os jacarés foram recapturados entre dois e dez anos após a marcação (2012–2022). Os dados indicam que o modelo monomolecular (von Bertalanffy por comprimento) é adequado para modelar o crescimento de animais de tamanho intermediário, e a recaptura de uma fêmea após oito anos indica que o modelo Rio Negro pode ser usado para modelar o crescimento com razoável precisão para indivíduos do Rio Xingu