The use and utility of surrogates in biodiversity monitoring programmes

摘要

Monitoring programmes are intended to inform effective biodiversity conservation and management (Legge et al.,2018).Well-designed programmes can establish baseline conditions,determine trends in threatened species populations,quantify the effects of management and provide warning of ecosystem changes (Magurran et al.,2010).For these reasons,biodiversity monitoring underpins the activities of land management agencies world-wide.However,it is not always possible to directly monitor key variables at ideal spatio-temporal resolutions,due to resourcing or logistic constraints.For example,direct monitoring of koalas (Phascolarctos cinereus) can be cost-and time intensive as koalas are cryptic,occur at low densities and are difficult to reliably observe in dense forest canopies (McAlpine et al.,2006).Where money,time or logistic challenges hamper monitoring efforts,managers may instead measure a surrogate in lieu of the direct variable of interest (Lindenmayer,Pierson,et al.,2015).While the distinction between surrogate and direct measurement can be ambiguous,here we define a biodiversity surrogate as an attribute of an ecosystem that is used as a proxy for another aspect of biodiversity of interest (Lindenmayer,Barton,& Pierson,2015).For koalas,the presence of faecal pellets on the forest floor is a rapid and reliable surrogate for estimating occupancy over large areas (McAlpine et al.,2006).