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Combining incidence and demographic modelling approaches to evaluate metapopulation parameters for an endangered riparian plant

View Article: PubMed Central - PubMed

ABSTRACT

Metapopulations are a central concept in ecology and conservation biology; however, estimating key parameters such as colonization rates presents a substantial obstacle to modelling metapopulations in many species. We develop spatial and non-spatial simulation models that combine incidence- and demographic-based approaches to build a relationship between observed patch occupancy, habitat turnover rates, colonization rates and dispersal scales. Applying these models to long-term observations of Pedicularis furbishiae (Furbish’s lousewort), a rare plant endemic to the Saint John River, we predict that observed habitat patches averaging 550 m in length receive colonizing seedlings with a yearly probability of 0.45 or 0.54, based on two different models. Predictions are consistent with a standard analytic metapopulation formulation modified to partition extinction drivers during the early and the late phases of a population’s life cycle. While the specific results rest on several simplifying assumptions, the models allow us to understand the impact that increasing rates of habitat turnover would have on the future survival of this species.

No MeSH data available.


Simulated occupancy in a non-spatial model of Pedicularis furbishiae at 61 habitat patches estimated from 15 iterations at each parameterization of colonization probability and habitat failure probability. Patch occupancy is defined as the number of habitat patches with at least one reproductive adult. Colonization probability is the yearly probability for a given unoccupied habitat patch that a seedling will establish in that patch. Habitat failure probability is the yearly probability that a catastrophic event will eliminate all plants in a given habitat patch.
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plw044-F2: Simulated occupancy in a non-spatial model of Pedicularis furbishiae at 61 habitat patches estimated from 15 iterations at each parameterization of colonization probability and habitat failure probability. Patch occupancy is defined as the number of habitat patches with at least one reproductive adult. Colonization probability is the yearly probability for a given unoccupied habitat patch that a seedling will establish in that patch. Habitat failure probability is the yearly probability that a catastrophic event will eliminate all plants in a given habitat patch.

Mentions: In our non-spatial model, the intersection of the observed annual habitat failure rate, 0.0042 (4 failures in 957 patch years), and the observed patch occupancy, 0.77, occurred in our model at an annual colonization probability of 0.45 (95 % CI = 0.29–0.75; Fig. 2). In this region, a 60 % increase in habitat failure probability results in a loss of ∼7 % of the occupied habitats at equilibrium. A 60 % increase in colonization probability in this region would result in a gain of ∼16 % more occupied habitats.Figure 2.


Combining incidence and demographic modelling approaches to evaluate metapopulation parameters for an endangered riparian plant
Simulated occupancy in a non-spatial model of Pedicularis furbishiae at 61 habitat patches estimated from 15 iterations at each parameterization of colonization probability and habitat failure probability. Patch occupancy is defined as the number of habitat patches with at least one reproductive adult. Colonization probability is the yearly probability for a given unoccupied habitat patch that a seedling will establish in that patch. Habitat failure probability is the yearly probability that a catastrophic event will eliminate all plants in a given habitat patch.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940506&req=5

plw044-F2: Simulated occupancy in a non-spatial model of Pedicularis furbishiae at 61 habitat patches estimated from 15 iterations at each parameterization of colonization probability and habitat failure probability. Patch occupancy is defined as the number of habitat patches with at least one reproductive adult. Colonization probability is the yearly probability for a given unoccupied habitat patch that a seedling will establish in that patch. Habitat failure probability is the yearly probability that a catastrophic event will eliminate all plants in a given habitat patch.
Mentions: In our non-spatial model, the intersection of the observed annual habitat failure rate, 0.0042 (4 failures in 957 patch years), and the observed patch occupancy, 0.77, occurred in our model at an annual colonization probability of 0.45 (95 % CI = 0.29–0.75; Fig. 2). In this region, a 60 % increase in habitat failure probability results in a loss of ∼7 % of the occupied habitats at equilibrium. A 60 % increase in colonization probability in this region would result in a gain of ∼16 % more occupied habitats.Figure 2.

View Article: PubMed Central - PubMed

ABSTRACT

Metapopulations are a central concept in ecology and conservation biology; however, estimating key parameters such as colonization rates presents a substantial obstacle to modelling metapopulations in many species. We develop spatial and non-spatial simulation models that combine incidence- and demographic-based approaches to build a relationship between observed patch occupancy, habitat turnover rates, colonization rates and dispersal scales. Applying these models to long-term observations of Pedicularis furbishiae (Furbish’s lousewort), a rare plant endemic to the Saint John River, we predict that observed habitat patches averaging 550 m in length receive colonizing seedlings with a yearly probability of 0.45 or 0.54, based on two different models. Predictions are consistent with a standard analytic metapopulation formulation modified to partition extinction drivers during the early and the late phases of a population’s life cycle. While the specific results rest on several simplifying assumptions, the models allow us to understand the impact that increasing rates of habitat turnover would have on the future survival of this species.

No MeSH data available.