Effects of roads on the vertebrates diversity of the Indigenous Territory Paresi and its surrounding
Roadkill impact is still underestimated due to the lack of knowledge of its intensity and effect on animal populations. To assess differences between animal roadkills on roads in distinct landscapes, this study recorded mesoand megavertebrate roadkills along 50 km during a year in two highways in the transitional area of Amazonia/Cerrado in Tangará da Serra, Mato Grosso: MT-358 and MT-235, the latter crossing the Paresi Indigenous Land. We assessed roadkill rates and points with higher rates of roadkills, recording the most impacted species, seasonal effects, biomass loss, activity period of species, and traffic volume. We recorded 178 roadkills in 4,950 km travelled, a rate of 0.035 animal/km-travelled. Mammals were the most impacted with 135 roadkills (75.8%), followed by reptiles (6.2%), amphibians (5.6%) and birds (5.1%). Among mammals 51.1% were Carnivora, and the most impacted species was Cerdocyon thous (n = 42). On highway MT-358 (human-modified landscape), we recorded 155 roadkilled mammals, and the most impacted were C. thous (23.9%) and Euphractus sexcinctus (13.5%). Whilst on highway MT-235 (Paresi Indigenous Land), we recorded 23 roadkilled mammals, and the most impacted were Myrmecophaga tridactyla (26.1%) and C. thous (21.7%). The low roadkill rate in the Paresi Indigenous Land might be related to the presence of fauna pathways along the highway and the availability of a forested landscape.
Mamíferos de médio e grande porte atropelados em rodovias do Estado de Santa Catarina, sul do Brasil
Running over of mammals on roads of Santa Catarina state, southern Brazil. Road deaths represent a factor of great impact on fauna. This is probably one of the main causes of mortality, even for threatened species. However, studies on this subject are unknown in Santa Catarina state, southern Brazil. Considering this lack, the present study presents records of medium to large-sized mammals killed by vehicles on the roads of this state between August 2000 and November 2005. In total, 257 records were made from 20 mammal species, most of which were obtained from the BR 116, BR 282 and BR 470 highways. Cerdocyon thous was the commonest species (82 records; 31.9%), followed by Didelphis albiventris (44; 17.1%), Procyon cancrivorus (21; 8.2%), Conepatus chinga (19; 7.4%), Dasypus novemcinctus (14; 5.4%), Tamandua tetradactyla (14; 5.4%) and Sphiggurus villosus (13; 5.1%). Leopardus tigrinus (5; 1.9%), L. wiedii (1; 0.4%) and one unidentified Leopardus individual were recorded as threatened species. This indicates a high number of mammals run over on the roads
Preservation in microbial mats: mineralization by a talc-like phase of a fish embedded in a microbial sarcophagus
Microbial mats have been repeatedly suggested to promote early fossilization of macroorganisms. Yet, experimental simulations of this process remain scarce. Here, we report results of 5 year-long experiments performed onfish carcasses to document the influence of microbial mats on mineral precipitation during early fossilization. Carcasses were initially placed on top of microbial mats. After two weeks, fishes became coated by the mats forming a compact sarcophagus, which modified the microenvironment close to the corpses. Our results showed that these conditions favoured the precipitation of a poorly crystalline silicate phase rich in magnesium. This talc-like mineral phase has been detected in three different locations within the carcasses placed in microbial mats for more than 4 years: 1) within inner tissues, colonized by several bacillary cells; 2) at the surface of bones of the upper face of the corpse buried in the mat; and 3) at the surface of several bones such as the dorsal fin which appeared to be gradually replaced by the Mg-silicate phase. This mineral phase has been previously shown to promote bacteria fossilization. Here we provide first experimental evidence that such Mg-rich phase can also be involved in exceptional preservation of animals.