3. Monitoring

Once the measures considered appropriate to mitigate a given impact have been selected and implemented, it is essential to assess their efficiency* and effectiveness**. This is necessary not only to identify project-specific corrections, but also, from a broader perspective, to build a body of knowledge and evaluations capable of supporting future procedures in similar situations (BECKMANN et al. 2010; CALTRANS 2009). Both approaches are fundamental stages of the “adaptive management” process proposed by SALAFSKI et al. (2001) as an appropriate way to maximize results in biodiversity conservation and natural-resource management. A central feature of this process is the incorporation of research into conservation actions, integrating systematic monitoring of management practices into their conceptual design and management strategy so that they can be evaluated, adjusted, and improved through experience. In short, evaluation of earlier stages informs the readjustment of subsequent stages and incorporates learning into the process.

The stages proposed for implementing adaptive management (Table 5) are readily applicable to the road–wildlife conflict and are also consistent with governmental environmental management:

As in Brazil, evaluation of the effectiveness of adopted measures is routine practice in the United States and Europe, but methods and sampling designs still lack standardization, making comparison among results difficult. The first issue is to define what should be considered the “efficiency” of a mitigation measure: a reduction in total mortality or in mortality of a particular species, the degree of use of wildlife crossings, or their use by the target group. It may also be desirable to determine whether the measures are in fact the most effective for maintaining population densities, biodiversity, or connectivity, among several other variables that may be considered (BANK et al. 2002; BECKMANN et al. 2010).

Monitoring costs and duration are directly related to the complexity of the level of biological organization being evaluated (BECKMANN et al. 2010). This is therefore another factor that must be considered when defining the experimental design, because the ideal duration and number of temporal and spatial replicates are not always compatible with available resources and the scale of the road project under licensing. Seasonality, represented by seasons of the year or rainfall regime depending on the region, is another factor that should be considered not only in the baseline assessment but also in monitoring (MATA et al. 2009).

Likewise, the area of influence of a particular project may not encompass a sufficiently large area for studies of more complex ecological processes. Such processes may extend beyond the proponent's responsibility and the scope of a specific licensing process, as discussed under 1.2. Environmental Baseline Assessment. At the current stage of road-ecology knowledge, basic data such as reductions in wildlife-vehicle collision rates, the degree of use of wildlife crossings, and species-specific responses to these structures therefore remain highly important for evaluating the effectiveness of adopted strategies.

ROEDENBECK et al. (2007) emphasize that social and economic motivations tend to relegate ecological aspects to a secondary role in transportation-system planning. To change this situation—in which environmental concerns are often introduced mainly through the relatively nonspecific “precautionary principle” rather than through robust scientific arguments—they recommend that road-ecology research meet two basic requirements: (a) it should be directly related to practical questions of road planning and construction, and (b) its experimental design should provide strong evidential value. Thus, despite the many methodological approaches available in this field, environmental licensing should prioritize methods that produce direct, objective, and quantifiable evidence of cause-and-effect relationships between road infrastructure and wildlife.

The extent to which results obtained for a particular project can be extrapolated is relatively limited because of the many factors that distinguish different contexts, including species composition, habitat extent, road characteristics, and topography. Nevertheless, the ability to collect data from a substantial number of licensed projects makes it possible to consolidate a database covering diverse situations, some of which may closely resemble the context under analysis and thus provide a more reliable basis for prediction.

Little information is available on successful wildlife crossing rates along road sections without mitigation systems. Although difficult to obtain, such information can be assessed by adapting methods such as track stations, video monitoring, and telemetry, and is highly important for evaluating the actual effectiveness and necessity of mitigation systems.

Monitoring periods differ among countries. In Brazil there are no fixed standards, although there is a tendency to require at least two years of monitoring after a road begins operating; in some cases, such as the Rota do Sol highway (RS-486), licensed by IBAMA, roadkill monitoring has continued for more than ten years. In France, for example, one year of monitoring is required, followed by reassessment after five years of operation (BANK et al. 2002).

*Efficiency means doing things correctly: it concerns the means used to achieve a result—the activity or what is done.
**Effectiveness means achieving the right result: it concerns the objective or purpose for which the action is undertaken.

Translation note: This English version was preliminarily translated using ChatGPT and has not yet undergone human review.