Patch Dynamics and Metapopulation Theory: the Case of Successional Species

National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, 735 State Street, Suite 300, Santa Barbara, CA, 93101-5504, U.S.A.
Journal of Theoretical Biology (Impact Factor: 2.12). 05/2001; 209(3):333-344. DOI: 10.1006/jtbi.2001.2269
Source: PubMed


We present a mathematical framework that combines extinction–colonization dynamics with the dynamics of patch succession. We draw an analogy between the epidemiological categorization of individuals (infected, susceptible, latent and resistant) and the patch structure of a spatially heterogeneous landscape (occupied–suitable, empty–suitable, occupied–unsuitable and empty–unsuitable). This approach allows one to consider life-history attributes that influence persistence in patchy environments (e.g., longevity, colonization ability) in concert with extrinsic processes (e.g., disturbances, succession) that lead to spatial heterogeneity in patch suitability. It also allows the incorporation of seed banks and other dormant life forms, thus broadening patch occupancy dynamics to include sink habitats. We use the model to investigate how equilibrium patch occupancy is influenced by four critical parameters: colonization rate, extinction rate, disturbance frequency and the rate of habitat succession. This analysis leads to general predictions about how the temporal scaling of patch succession and extinction–colonization dynamics influences long-term persistence. We apply the model to herbaceous, early-successional species that inhabit open patches created by periodic disturbances. We predict the minimum disturbance frequency required for viable management of such species in the Florida scrub ecosystem.

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Available from: Hugh P Possingham, Mar 20, 2015
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    • "Empirical examples of such systems are agricultural landscapes in which habitable areas are frequently changed by mowing and harvesting, lands in which flood and inundation events are frequent, and early-successional communities in disturbed sites, where the habitat quality declines due to resource depletion and the timing for habitat to become suitable for recolonization depends on disturbance (Stelter et al. 1997; Amarasekare and Possingham 2001; Blaum et al. 2012). In all of these systems dispersal is closely linked to the state of the habitat patch, and longterm survival in such habitat systems depends on the timing of dispersal. "
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    ABSTRACT: Abstract A challenge for conservation management is to understand how population and habitat dynamics interact to affect species persistence. In real landscapes, timing and duration of disturbances can vary, and species' responses to habitat changes will depend on how timing of dispersal and reproduction events relate to the landscape temporal structure. For instance, increasing disturbance frequency may promote extinction of species that are unable to appropriately time their reproduction in an ever-changing habitat and favor species that are able to track habitat changes. We developed a mathematical model to compare the effects of pulsed dispersal, initiated by shifts in habitat quality, with temporally continuous dispersal. We tested the effects of habitat (and population) turnover rates on metapopulation establishment, persistence, and long-term patch occupancy. Pulsed dispersal reduced patch occupancy and metapopulation longevity when habitat patches are relatively permanent. In such cases, demographic extinction was the primary form of local extinction. Conversely, when habitat patches are short-lived and new ones are frequently formed, pulsed dispersal promoted rapid colonization, increased occupancy, and prolonged metapopulation persistence. Our results show that species responsiveness to habitat disturbance is critical to metapopulation persistence, having profound implications for the species likely to persist in landscapes with altered disturbance regimes.
    The American Naturalist 02/2015; 185(2):183-195. DOI:10.1086/679502 · 3.83 Impact Factor
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    • "Keymer et al., 2000; Amarasekare and Possingham, 2001; Wimberly , 2006), mostly focusing on a comparison between dynamical vs static systems. In general, these theoretical studies have shown that metapopulation occupancy of ephemeral habitats is lower than that of permanent habitats (Amarasekare and Possingham, 2001) and that habitat turnover rate is negatively correlated with patch occupancy (Keymer et al., 2000). An intuitive implication of these shifting mosaics is that, at some point, as habitat conditions worsen, individuals using a patch will need to relocate into other patches of suitable habitat. "
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    ABSTRACT: Plantation clearcuts represent an important habitat for many open-area wildlife species – including conservation-concern species – in landscapes dominated by industrial forests. However, due to the ephemeral nature of clearcuts, species using this type of environment face a “shifting mosaic” in which their ability to successfully relocate to another habitat patch may play a crucial role in the species’ persistence in the landscape. Although several studies have shown a positive effect of patch size on the persistence of open-habitat species, forest clearcutting represents a special case in which, on average, larger patches also tend to be more isolated from each other, likely creating a trade-off between area and isolation effects. We developed an individual-based spatially-explicit model to test the effect of clearcut size (a critical management variable in plantation forestry) on the persistence of generic early-successional wildlife species in a landscape dominated by forest plantations. We simulated a landscape covered with a plantation harvested regularly over a 25-year rotation and different versions of a wildlife population whose habitat was constituted only by 1–4year-old patches. We observed that when the species could perceive the attributes of the neighboring pixels persistence time was higher at intermediate clearcut sizes agreeing with our prediction. Also, species with a high dispersal capacity were less limited by connectivity and reached their maximum persistence at higher clearcut sizes. Results also showed a positive effect of habitat lifetime on persistence. Our results suggest large clearcuts may be incompatible with the conservation of many early-successional vertebrates that have limited dispersal capacity, unless additional conservation measures, such as the use of corridors or special spatial arrangement of clearcuts, are taken to overcome the lack of connectivity.
    Biological Conservation 05/2011; 144(5):1577-1584. DOI:10.1016/j.biocon.2011.02.003 · 3.76 Impact Factor
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    • "This framework has been useful for the study of species threatened with extinction by habitat loss and fragmentation (Harrison, 1994; Litvaitis and Villafuerte, 1996) and species that occur in successional habitats maintained by disturbance (Litvaitis, 1993). Advances in metapopulation theory have accounted for the effect of patch succession on population persistence (Ellner and Fussmann, 2003; Hastings, 2003; Johnson, 2000; Thomas, 1994), but this has rarely been demonstrated empirically (Amarasekare and Possingham, 2001; Stelter et al., 1997). An empirical understanding of the influence of succession within each patch and on an entire metapopulation is critical to the recovery of species dependent on early successional habitats and threatened by habitat loss and fragmentation (Litvaitis, 1993). "
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    ABSTRACT: The Lower Keys marsh rabbit (LKMR, Sylvilagus palustris hefneri), a marsh rabbit subspecies endemic to the Lower Keys, Florida was protected in 1990, however, populations continue to decline despite recovery efforts. We hypothesized on-going habitat loss and fragmentation due to succession and hardwood encroachment has lead to increased edge, reduced habitat quality, and increased activity by native raccoons (Procyon lotor). These factors reduce the suitability of patches in a later successional state, thus threatening LKMR recovery and metapopulation persistence. We surveyed 150 LKMR patches in 2008, tallying adult and juvenile rabbit pellets, estimating measures of habitat succession and quality (woody and herbaceous ground cover, distribution of herbaceous species) and recording raccoon activity (number of raccoon signs). We calculated patch edge (patch shape index) using ArcGIS. We evaluated the relationship between patch and habitat attributes and LKMR using regression analysis and model selection. We found both adult and juvenile LKMR pellet counts were lower in patches with higher shape indices and higher in patches with greater occurrence of bunchgrasses and forbs. We also found adult LKMR pellet counts were lower in patches with higher raccoon activity. Our results suggest patch edge, habitat succession and quality, and raccoons pose a threat to the persistence and recovery of LKMR populations. Recovery efforts should focus on reducing these trends through habitat management and raccoon removal implemented in carefully controlled experiments with proper monitoring. Measures of patch and habitat attributes important to LKMR should be incorporated into long-term metapopulation monitoring and used to evaluate recovery actions.
    Biological Conservation 11/2010; 143(11-143):2703-2710. DOI:10.1016/j.biocon.2010.07.016 · 3.76 Impact Factor
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