Integrating social and ecological data to model metapopulation dynamics in coupled human and natural systems

Abstract

Understanding how metapopulations persist in dynamic working landscapes requires assessing the behaviors of key actors that change patches as well as intrinsic factors driving turnover. Coupled human and natural systems (CHANS) research uses a multidisciplinary approach to identify the key actors, processes, and feedbacks that drive metapopulation and landscape dynamics. We describe a framework for modeling metapopulations in CHANS that integrates ecological and social data by coupling stochastic patch occupancy models of metapopulation dynamics with agent‐based models of land‐use change. We then apply this framework to metapopulations of the threatened black rail (Laterallus jamaicensis) and widespread Virginia rail (Rallus limicola) that inhabit patchy, irrigation‐fed wetlands in the rangelands of the California Sierra Nevada foothills. We collected data from five diverse sources (rail occupancy surveys, land‐use change mapping, a survey of landowner decision making, climate and reservoir databases, and mosquito trapping and West Nile virus testing) and integrated them into an agent‐based stochastic patch occupancy model. We used the model to (1) quantify the drivers of metapopulation dynamics, and the potential interactions and feedbacks among them; (2) test predictions of the behavior of metapopulations in dynamic working landscapes; and (3) evaluate the impact of three policy options on metapopulation persistence (irrigation district water cutbacks during drought, incentives for landowners to create wetlands, and incentives for landowners to protect wetlands). Complex metapopulation dynamics emerged when landscapes functioned as CHANS, highlighting the importance of integrating human activities and other ecological processes into metapopulation models. Rail metapopulations were strongly top‐down regulated by precipitation, and the black rail's decade‐long decline was caused by the combination of West Nile virus and drought. Theoretical predictions of the two metapopulations’ responses to dynamic landscapes and incentive programs were complicated by heterogeneity in patch quality and CHANS couplings, respectively. Irrigation cutbacks during drought posed a serious extinction risk that neither incentive policy effectively ameliorated.

A practical guide for combining data to model species distributions

“…, Van Schmidt et al. ). By integrating multiple sources of information into the modeling process, greater insights into environmental relationships and the mechanisms driving species distributions can occur.…”

Innovations in data integration for modeling populations

“…Van Schmidt et al. () tackle the integration of social and ecological data via an agent‐based modeling approach to understand metapopulation dynamics in coupled human and natural systems (Fig. ).…”

“…Van Schmidt et al. () combine five interdisciplinary data sets to model the metapopulation dynamics of the threatened Black Rail ( Laterallus jamaicensis ) in a coupled human and natural system, the irrigated rangelands of the foothills of California's Sierra Nevada. Their paper provides an example of integrating social and ecological data by coupling agent‐based models of land‐use change with a stochastic patch occupancy model of metapopulation dynamics.…”

The rescue effect and inference from isolation–extinction relationships

“…Season‐ and site‐specific probabilities were modeled as covariates via logit‐link functions. Our models included covariates that previous analyses identified as important predictors of rail metapopulation dynamics in this region (Richmond et al ; Van Schmidt et al ): sampling period‐specific detection probabilities, precipitation (mean over the past 120 days), and wetlands’ patch area, elevation (Geological Survey ), geomorphology and water sources (Appendix ).…”

“…Breeding season occupancy surveys of these metapopulations have been conducted annually for over a decade. Preliminary analyses of isolation–extinction relationships from 2002 to 2006 (Appendix ), a period with both metapopulations in dynamic equilibrium (Van Schmidt et al ), suggested the rescue effect was strong in black rails but not supported for Virginia rails (Fig. ).…”