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.
Dispersal distances are commonly inferred from occupancy data but have rarely been validated. Estimating dispersal from occupancy data is further complicated by imperfect detection and the presence of unsurveyed patches. We compared dispersal distances inferred from seven years of occupancy data for 212 wetlands in a metapopulation of the secretive and threatened California black rail (Laterallus jamaicensis coturniculus) to distances between parent-offspring dyads identified with 16 microsatellites. We used a novel autoregressive multi-season occupancy model that accounted for both unsurveyed patches and imperfect detection to quantify patch isolation using buffer radius (BRM) and incidence function (IFM) connectivity measures at 15 scales (1-10, 15, 20, 25, and 30 km). Connectivity measures were then fit as colonization covariates in occupancy models to estimate a model-averaged dispersal distance. As predicted, colonization was more strongly related to connectivity at small spatial scales (<10 km). AIC weights were greatest at 7 km for BRM and at 4 km for IFM. Model-averaged dispersal distances (BRM = 7.46 km; IFM = 5.48 km) showed good agreement with the mean M(±SE) dispersal distance from 23 parent-offspring dyads (5.58 ± 1.92 km), indicating reasonably accurate mean dispersal distances can be inferred from occupancy data when isolation strongly affects colonization.
The rescue effect in metapopulations hypothesises that less isolated patches are unlikely to go extinct because recolonisation may occur between breeding seasons (‘recolonisation rescue’), or immigrants may sufficiently bolster population size to prevent extinction altogether (‘demographic rescue’). These mechanisms have rarely been demonstrated directly, and most evidence of the rescue effect is from relationships between isolation and extinction. We determined the frequency of recolonisation rescue for metapopulations of black rails (Laterallus jamaicensis) and Virginia rails (Rallus limicola) from occupancy surveys conducted during and between breeding seasons, and assessed the reliability of inferences about the occurrence of rescue drawn from isolation–extinction relationships, including autologistic isolation measures that corrected for unsurveyed patches and imperfect detection. Recolonisation rescue occurred at expected rates, but was elevated during periods of disturbance that resulted in non‐equilibrium metapopulation dynamics. Inferences from extinction–isolation relationships were unreliable, particularly for autologistic measures and for the more vagile Virginia rail.
A successful species reintroduction depends, in part, on the correct identification of suitable habitats. In cases where a species has been extirpated from a region for decades, however, this task is fraught with uncertainty. Uncertainty can be minimized and adjusted for by monitoring and adaptive management. The central goal of this study was to identify reintroduction sites that facilitate dispersion of whooping cranes (Grus americana), a federally listed endangered species, into optimal habitat as quickly as possible. First, we described the habitat selection of breeding home ranges for reintroduced whooping cranes in and around Necedah National Wildlife Refuge of central Wisconsin. We defined home ranges as 95% fixed spatial kernel density estimates from location data gathered from nesting whooping cranes from April through July 2005–2010. Whooping crane home ranges contained more emergent herbaceous wetlands than expected by chance and less developed or barren land, forest, and scrubland. Breeding whooping crane home ranges usually were composed of distinct nesting territories and off‐territory elements; when moving off‐territory, cranes decreased wetland selection and increased selection for open uplands. Second, we used habitat composition values and strength of selection (as determined by Jacob's index) to create a habitat suitability map to identify potential habitats that breeding whooping cranes could use in unoccupied eastern Wisconsin. With this method, we identified 2 large suitable wetland complexes within our study area associated with the Fox and Rock Rivers. Based on this analysis, the Whooping Crane Eastern Partnership began releasing whooping cranes into White River Marsh State Wildlife Area and Horicon National Wildlife Refuge in 2011. © 2014 The Wildlife Society.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.