- Jonathan Rhodes
Rules for Monitoring Species
Determining which species to monitor is a critical question in conservation. Monitoring helps quantify changes in ecosystems and ecological communities and informs choices of management activities. Yet, there are few rules that help inform the choice of species to monitor so that the effectiveness of management interventions is a maximised. In a recent paper of ours, led by Howard Wilson, we address exactly this issue by seeking principles for prioritising the monitoring of species to inform management.
We consider the common encountered case where species must be prioritised for recovery actions based on some measure of the risk of decline and cost (e.g., Jospeph et al. 2009), but information about whether each species is declining or not is uncertain. In these cases the monitoring of species can help to resolve uncertainty about the decline of species and therefore improve decsion-making about which species to prioritise recovery actions for. But which species should we monitor?
We develop rules that show that the best species to monitor are: (1) those at the boundary between species that are prioritised for recovery actions and those that are not, and (2) those for which we are most uncertain about whether they are declining or not. In other words, apart from uncertainty driving monitoring priorities, monitoring priorities are determined by which species are most likely to change our management decisions. This is unlikely to be the species at the very top of our management priority list (we are pretty certain they are a good bet anyway), or those at the very bottom of our management priority list (we are pretty certain they are not a good bet anyway), but rather species that are not allocated resources, but close to having resources allocated to them, or allocated resources, but close to not having resources allocated to them. Although we kept our framework simple, these rules were found to be robust to a range of assumptions, such as allowing for heterogeneity in management effectiveness or Type I and Type II errors.
Choosing monitoring strategies for conservation is difficult because ultimately the benefit depends on a complex chain of cause and effect from monitoring to management improvement. We hope that rules such as the ones we have developed in this paper will make the task of identifying effective monitoring strategies just that little bit easier.