Information costs of reduced-effort habitat monitoring in a butterfly recovery program

Habitat monitoring typically requires a large amount of effort and resources. Project managers are likely to consider cost-cutting options but they may not critically review the information costs of implementing those options. An effort recently began in New York State to monitor critical habitat and restoration progress aimed at recovering the federally endangered Karner blue butterfly (Lycaeides melissa samuelis). Specific strategies were proposed to increase efficiency of fieldwork: (1) estimate larval host plant (wild blue lupine, Lupinus perennis) abundance from cover data, (2) area-based standardization of sample size for nectar sampling, (3) use a minimum cover threshold to trigger nectar species counts, (4) use multiple observers. I quantitatively reviewed these time savers for effects on raw data quality, and for potential effects on interpreting habitat quality as part of recovery criteria. Cover-based models of lupine abundance differed between metapopulation recovery areas, area-based sampling was sufficient to detect over 80% of priority nectar species in most sites, nectar information loss was high due to the minimum cover threshold, and overall results from different observers were similar with one exception. Direct lupine stem counting is recommended over cover estimation, statistical interpolation (rarefaction) and extrapolation (asymptotic estimators) is recommended over area-based nectar sampling, use of minimum cover criteria is strongly discouraged, and field crews need botanical expertise and careful instructions. This example highlights why strategies to save time and money with monitoring fieldwork should be 'put to the test'.