Metapopulation Dynamics of Bobolinks Occupying Agricultural Grasslands in the Midwestern United States

• Published in: The American midland naturalist 2007-10, Vol.158 (2), p.415-423
• Main Authors: SCHEIMAN, DANIEL M, DUNNING, JOHN B, WITH, KIMBERLY A
• Format: Article
• Language: English
• Subjects: Bird banding; Bird nesting; Birds; Connectivity; Environmental aspects; Extinction; Extinction (Biology); Grasslands; Habitat (Ecology); Habitat conservation; Habitat loss; Islands; Management decisions; Metapopulation ecology; Population dynamics; Probability; s; Species extinction; Wildlife conservation; Wildlife habitats
• ISSN: 0003-0031; 1938-4238
• DOI: 10.1674/0003-0031(2007)158[415:MDOBOA]2.0.CO;2

A metapopulation is any set of populations that are patchily distributed and potentially connected by dispersal. This broad definition includes classical, mainland-island, source-sink, patchy and non-equilibrium metapopulations. To ensure long-term regional population viability in a fragmented landscape we need a better understanding of metapopulation dynamics. To determine which metapopulation model applies to a given species, Stith et al. (1996) developed a classification scheme using species-specific estimates of dispersal distance and local extinction risk. We used this scheme to classify bobolink (Dolichonyx oryzivorus) populations occupying fragmented, agricultural grasslands in the Midwestern United States. We estimated the distribution of dispersal distances using mark-recapture techniques and calculated local extinction risk. Dispersal rate and turnover were high, indicating that populations were highly connected. Local extinction probability was 4%, indicating that populations were “midlands” and vulnerable to extinction. Well-connected populations constitute a patchy metapopulation according to Stith et al.'s (1996) scheme. Bobolink dispersal ability was sufficient to overcome habitat fragmentation. Our research showed that the Stith et al. (1996) classification can be applied to a migratory species, but should be expanded to the metalandscape scale.