Project Results

We sampled the snake fauna in 13 landscapes along 80 km of highway and in the adjacent vegetation cover in the Colombian Llanos. We registered  119 snakes belonging to 33 species. Traffic levels significantly influenced rates of snake road kill, while adjacent vegetation cover, rainfall seasonality, and landscape structure and composition did not. We classified the species into seven ecological groups based upon foraging strategy, body length, and habitat preferences. Although most of the roadkilled species had an active foraging strategy, all of the ecological groups contained some species that were killed on the highway, as well as some species that inhabited adjacent vegetation cover but that were not detected on the highway. The different ecological groups were not associated with different landscape characteristics. Six of the 13 landscapes that presented the lowest species richness of road-killed species had a different ecological group represented by each of the species documented as road kills. Thus, considering the ecological group that a species belongs to provides a complementary analytical approach that permits a fuller understanding of the ecological effects of roads on the functional role of the species in the ecosystem. We recommend focusing mitigation measures on highway sectors with the greater vehicular flow, employing both preventive measures such as posting driver advisories and installing speed radars and conducting environmental education programs to raise awareness of local drivers.

About This Project

Within reptiles, snakes are the group most affected by roads due to factors intrinsic to their ecology and their complex patterns of movement, which leads them to use different habitat types for basking, shelter and foraging. In this study we propose to identify how landscape heterogeneity, seasonality, and ecological aspects of different snake species associate with patterns of mortality on a road. Such information is essential to help mitigate the impacts of roads on snake communities.

Ask the Scientists

What is the context of this research?

Snakes are the reptiles that die the most on roads. Their roadkill rates in Colombia is estimated at 176,660 snakes per year (Lynch, 2012). In the state of Meta, where our project takes place, a recent study revealed that 131 snakes from 21 species were run over in only 51 days (Rincón et al. 2015). This result suggests that roads in the area are a significant threat to this group that locally represents approximately 14.37% of the national snake species diversity, including two endemic and threatened endangered species. Despite this estimation, very few studies have evaluated the impacts of roads on snake communities in Colombia (Quintero-Angel et al. 2012) and none of them have assessed the main factors contributing to roadkill, until now.

What is the significance of this project?

Our study aims to identify the patterns of richness, abundance, composition and dominance of snake species in the landscape mosaic that surrounds a road located in a highly biodiverse area, and will identify its relation with patterns of snake mortality. This research will contribute to enhance the knowledge about the road ecology by assessing not only factors previously evaluated by other studies
(e.g. , species ecology and seasonality), but also factors not previously considered, such as the influence of landscape heterogeneity on roadkill patterns. Our results will provide new insights on the specific factors influencing snake roadkill rates in the tropics, particularly in savanna areas, which is essential to help mitigate the impacts of roads on snake communities.

What are the goals of the project?

The main goal of this project is to identify how seasonality and landscape heterogeneity associate with patterns of snake mortality on a road located in the savannah of eastern Colombia. To achieve this goal, we evaluate the richness, abundance, composition and evenness of snake species in the area adjacent to the road at 13 points with different degree of landscape heterogeneity, during both the rainy and dry seasons. Besides, We aim to dentify how these parameters explain patterns of snake roadkills; and establish the relationship of factors such as foraging habits, body size, and sex with the mortality rates of different species. Taking an approach where seasonal and spatial factors are considered will provide us with the tools needed to suggest future conservation strategies.