Alternative measurement endpoints include the amount of insurance money spent, number of hospitalizations due to animal-vehicle collisions or collision avoidance, or number of wildlife-vehicle collisions concerning species that potentially impact human safety, regardless of whether they resulted in human injury or death. Two measurement endpoints are suggested to assess effects of road mitigation measures on wildlife health and mortality, i.e., the number of animals killed or injured while crossing roads and the number of animals killed or with ill-health due to

isolation from needed resources through the barrier effect of roads (Table 2). These measurement endpoints seem to complement each other as each endpoint addresses a different mechanism through which wildlife health and mortality can be positively affected by wildlife crossing structures, i.e., through a reduction GS-1101 in vitro in animal-vehicle collisions or through Selleck NSC 683864 increased road permeability and hence increased access to resources. Therefore, we suggest to always use these endpoints together. Eight measurement endpoints are suggested to assess effects of road mitigation measures on population

viability (Table 2). The most informative measurement endpoint is the trend over time in the size (or density) of the local population. Trend in population selleck size is fundamental to understanding how the species has responded to the road mitigation. For example, if existing roads are having population-level effects and crossing structures are successful in mitigating those effects we would expect to see increases in population size after the structures are installed. If the crossing structures are installed on a new road, successful mitigation would be indicated by no change in the size IMP dehydrogenase of the wildlife population. Population size itself is also related to population persistence, since smaller populations are more likely to go extinct

by chance. When it is not possible to estimate population size or trend, a reduction in road-kill numbers following mitigation may provide an indicator for mitigation effectiveness at population level, but only if compared with road-kill numbers at control sites (see also Step 4) and if assumed (which may not hold) that (1) mortality is the main mechanism through which roads affect the population, and (2) road-induced mortality is not counteracted by, e.g., increased reproduction or immigration. As both assumptions may not apply (but see Hels and Buchwald 2001), changes in road-kill numbers should be seen as less indicative than estimates of population size or trend. Similarly, reproductive success as an indicator for mitigation effectiveness at the population level should be used with care, as no increase in reproductive success following mitigation may be the result of higher reproduction levels pre-mitigation as a response to loss of individuals due to road mortality.