A positive feature of these measurement endpoints is that changes may be detected sooner in population structure than in population trend. However, they are less closely tied to population viability so more extrapolation is necessary, and they are only applicable to species that show Tideglusib cost differential selleck chemical age or sex responses to the road or

traffic. Road permeability measurement endpoints, such as between-population movement and gene flow may also allow inferences to population-level mitigation, if the main population-level effect of the road is through movement (rather than, say, mortality). Increased movements between populations divided by roads may affect, e.g., dispersal success or access to mates (see, e.g., Mansergh and Scotts 1989) and consequently population PLX-4720 dynamics. Migrations across wildlife crossing structures may restore gene flow and reduce road-related genetic

differences between the populations (Gerlach and Musolf 2000; Vos et al. 2001; Epps and McCullough 2005; Arens et al. 2007; Björklund and Arrendal 2008; Balkenhol and Waits 2009; Corlatti et al. 2009). Although both measurement endpoints directly address the extent to which the barrier effect of roads is reduced, endpoint extrapolation is rather high because demographic and genetic connectivity between populations are not necessarily related to population viability. An even less direct indicator of a change in population viability is a change in genetic variability within the population. Genetic variability is thought to be positively correlated with population viability (Frankham 1996, 2005; Lacy 1997; Reed and Frankham 2003; Reed et al. 2007). Small populations that result

from increased mortality or habitat fragmentation lose genetic variability as a result of genetic drift or inbreeding (Keller and Largiader 2003). The disadvantage of genetic variability as an endpoint is that the correlation between genetic variability and population persistence is not well understood. However, changes in genetic diversity—as an important part of biodiversity—may in itself be considered as an assessment endpoint. Step 4: Select study design Appropriate study design, i.e., the spatial and temporal sampling scheme, is critical for determining the effectiveness Lonafarnib price of road mitigation. It is the responsibility of the ecologists involved in the research and monitoring process to ensure the design is rigorous and provides useful information. As argued by Roedenbeck et al. (2007), the optimal study design is a replicated BACI (Before–After–Control–Impact), where data are collected before and after road mitigation, both at sites where mitigation measures are being taken (impact sites—hereafter referred to as mitigation sites) and at sites that are similar to these sites but where no mitigation measures are taken (control sites).