The paper “Reptiles in danger: Implications of road mortality in wetlands of South America” does a great job at comparing different sites in the Parana River floodplain roads in relation to seasons, species diversity, abundance, and hotspots. There relationships of magnitude, timings, and locations were able to be pooled together through the researcher’s analysis of intrinsic (habitat use), extrinsic (temperature, precipitation, hydrometric levels) and anthropogenic factors (traffic volume) The visualization did a good job at illustrating the results, especially Fig.3 with relation to seasons and number of reptiles roadkill’s at the three sites. This helps to realize that there are so many factors that can be considered. Along with other papers the results bring more attention to placing more emphasis on conservation management to be geared on amphibians and reptiles that are the highest susceptible subjects to road mortality rates in wetlands. It was found that species richness had a significant increase as altitude decreases due to rising temperatures. Hence, the North region had higher richness of reptile species, but lowest abundance of reptile roadkill’s. The habit for this region consisted of the highest spatial heterogeneity of forest and wetland structure that aided in microhabitats for snakes.
This paper caught my attention due to the fact that it looks at road mortality specifically in relation to wetlands of South America. Since I work at an urban forest that has a wetland area with a wild population of different species of turtles. This paper calls to me because of the emphasis on higher vulnerability to reptiles due to thermoregulation and slow movement. Moreover, with the knowledge that each individual has their own home range while one goes out way farther some stay in their usual area. In the past year outside of my working area I have come across two turtles in the road that I have moved that would have otherwise been hit by another incoming car. Then, at my internship in Massachusetts one summer I would see so many turtles that would be moved off the roads. Hence, why this topic intrigues me and not just on turtles but also other species such as snakes that people especially don’t really care about swerving around.
I believe that the researchers could improve their data analysis of the environmental conditions’ variables. Such as providing more accurate precipitation readings by collecting days using Kestrels instead of just noting the average precipitation of the last three days. Moreover, there could have been more visits to the roads to include more data. It is stated that the data of GLMM showed that precipitation had no effect on reptile roadkill abundance. This raises an even higher concern that data could have been collected better for more accurate precipitation readings. This is due to the fact that it is widely known that reptiles often become more active after a precipitation event. These events could have been missed due to the short sampling period of taking the environmental condition measurements. However, it is a good point that the researchers did state that seasons were part of the additional variables which took part in the significant variations seen in the GLM abundance of reptile roadkill’s. It was found that Autumn had the highest species abundance compared to spring, winter, and summer. Additionally, spring has a higher number of roadkill’s compared to winter. This is important in creating modified mitigation strategies for each season that calls for different levels of risks to wildlife.
Other additional variables that should be considered are zones such as school, residentials, and industries, in relation to the differing speed limits to show if there is a correlation between the speed limits and roadkill. This could help in shifting conservation attention to zones that have lower or higher levels of speed limits to consider altering the levels for better visibility. Especially when overlapping with the sections North (NS), Centre (CS), and South (SS) of Parana River that were observed to have higher numbers of roadkill and compare those zones. I might have done a number of days for overall data collection differently in that increasing the field visits to have had the different regions of NS, CS, and SS meet the minimum number required for Autumn Optimized Hot Spot Analysis. This would have helped to have greater data on hotspots not just for region SS but for the others.
I appreciate how in the paper’s discussion two plausible reasons were given for how in the study a large proportion of reptile roadkill were snakes One that there is just a greater snake species richness in the area and second that people intentionally run over snakes. Additionally, how factors such as size of the snakes affect home range and movement frequencies when looking at factors such as foraging and being ectothermic animals. This builds onto the later elaboration on how pregnant snake females use the roads for thermoregulation which find themselves at higher risks of people just killing them by hand or by vehicles even in protected areas. This helps the readers to understand how even people’s perspectives on certain species a variable in species survivorship rates is also. Moreover, the highest world-wide threatened reptile species are those that live in freshwater environments that are not subject to negative effects from human activities. Future research directions are looking at study designs of roadkill’s in terms of reproductive seasons, exposure levels, and human population densities.