Roads (of all kind, including those unpaved) are pervasive and present nearly everywhere on earth. The number keeps growing exponentially. Roads bring traffic, and cars bring people. The impact of roads and the associated traffic on biodiversity is very deep and at many different levels, from the most obvious habitat loss and pollution to road kills, barrier effects and individual behavioral responses, just to mention a few. One of the first steps when approaching any applied issues starts with a description of the problem. Here we pursue the general description of patterns in variables such as mortality or spatial responses towards roads of different types. It might seem obvious but there are not that many works doing this in the literature. A good example here is the PhD of Marcello D'Amico.
D'Amico M, J Román, L de los Reyes, E Revilla. Road-kills in Mediterranean habitats: who, when and where? submitted
D'Amico M, S Periquet J Román, E Revilla. Generalised ungulate responses to roads and traffic intensity: How low traffic is too much? Submitted
A second step after having a adequate description of the problem is improving our understanding of the processes involved and the variables that mediate the impacts. The final aim is having some capacity to predict impacts (e.g. where, when, who). One example is the research on barrier effects, which are the outcome of a combination of road avoidance plus the filtering imposed by mortality on the individuals attempting to cross. In the end the most interesting and useful part is having the ability to extrapolate across systems, sites and scales (e.g. overall population impacts). Many of the examples here come from the collaboration with Dr Clara Grilo.
Grilo C, D Reto, J Felipe, F Ascensão, E Revilla (2014). Understanding the mechanisms behind road effects: linking occurrence with road mortality in owls. Animal Conservation 17:555-564 doi: 10.1111/acv.12120
Grilo C, J Sousa, F Ascensão, H Matos, I Leitão, P Pinheiro, M Costa, J Bernardo, D Reto, R Lourenço, M Santos-Reis, E Revilla. (2012) Individual spatial responses towards roads: implications for mortality risk. PLoS ONE 7(9): e43811. doi:10.1371/journal.pone.0043811
Kramer-Schadt, S., E. Revilla, T. Wiegand & U. Breitenmoser. (2004) Fragmented landscapes, road mortality and patch connectivity: modelling influences on the dispersal of the Eurasian lynx. Journal of Applied Ecology 41:711-723
Apart from the actual quantification of the problem, in applied issues the gained knowledge should be used to help in solving or at least in mitigating some of the impacts. The design and evaluation of mitigation measures is a relevant part of this research topic.
D'Amico M, AP Clevenger, J Román, Revilla. Generic versus specific surveys: estimating the effectiveness of road-crossing structures for small mammals. Journal of Wildlife Management in press
Villalva P, Reto D, Santos-Reis M, Revilla E, Grilo C (2013) Do dry ledges reduce the barrier effect of roads? Ecological Engineering 57:143-148. doi:10.1016/j.ecoleng.2013.04.005