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Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management.

Wood KA, Stillman RA, Daunt F, O'Hare MT - PLoS ONE (2014)

Bottom Line: However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement.New methods which address these issues and offer effective wildlife management are required.The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems.

View Article: PubMed Central - PubMed

Affiliation: Centre for Ecology and Hydrology, Edinburgh, United Kingdom; Faculty of Science & Technology, Bournemouth University, Dorset, United Kingdom.

ABSTRACT
Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems.

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Related in: MedlinePlus

The predicted depletion of aquatic plant biomass in the model river patch after 22 days (i.e. biomass after grazing) varied with the initial aquatic plant biomasses (i) inside the model river patch and (ii) in the river outside of the model.These were based on one-at-a-time changes in aquatic plant biomass, rather than simultaneous changes in both in-model and out-model biomass. Depletion is expressed as (a) percentage, and (b) absolute aquatic plant biomass.
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pone-0104034-g003: The predicted depletion of aquatic plant biomass in the model river patch after 22 days (i.e. biomass after grazing) varied with the initial aquatic plant biomasses (i) inside the model river patch and (ii) in the river outside of the model.These were based on one-at-a-time changes in aquatic plant biomass, rather than simultaneous changes in both in-model and out-model biomass. Depletion is expressed as (a) percentage, and (b) absolute aquatic plant biomass.

Mentions: Our model predictions of aquatic plant biomass were robust to large changes (±60%) in the values of 13 out of 15 parameters (Figure 2). However, our model predictions were highly sensitive to changes in the initial aquatic plant biomass both within the river patch and outside of the model, as these values strongly determined when the swans should stop grazing within the model and emigrate. Swans would emigrate from the model river patch to the river outside the model during the time step where the aquatic plant biomass of the model river patch decreased below the aquatic plant biomass of the river outside the model. Reducing the initial aquatic plant biomass of the model river patch reduced depletion to 0 g DM m−2 as swans emigrated on the first time step and thus did not feed inside the model (Figure 3). In contrast, increasing the initial biomass within the model river patch increased depletion, as emigration was delayed due to the greater biomass. Depletion reached 200 g DM m−2 for a 100% increase in aquatic plant biomass inside the model river patch. Reduced biomass in the river outside the model increased depletion within the model, up to a maximum of 70 g DM m−2 for ≥−40% change.


Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management.

Wood KA, Stillman RA, Daunt F, O'Hare MT - PLoS ONE (2014)

The predicted depletion of aquatic plant biomass in the model river patch after 22 days (i.e. biomass after grazing) varied with the initial aquatic plant biomasses (i) inside the model river patch and (ii) in the river outside of the model.These were based on one-at-a-time changes in aquatic plant biomass, rather than simultaneous changes in both in-model and out-model biomass. Depletion is expressed as (a) percentage, and (b) absolute aquatic plant biomass.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4117538&req=5

pone-0104034-g003: The predicted depletion of aquatic plant biomass in the model river patch after 22 days (i.e. biomass after grazing) varied with the initial aquatic plant biomasses (i) inside the model river patch and (ii) in the river outside of the model.These were based on one-at-a-time changes in aquatic plant biomass, rather than simultaneous changes in both in-model and out-model biomass. Depletion is expressed as (a) percentage, and (b) absolute aquatic plant biomass.
Mentions: Our model predictions of aquatic plant biomass were robust to large changes (±60%) in the values of 13 out of 15 parameters (Figure 2). However, our model predictions were highly sensitive to changes in the initial aquatic plant biomass both within the river patch and outside of the model, as these values strongly determined when the swans should stop grazing within the model and emigrate. Swans would emigrate from the model river patch to the river outside the model during the time step where the aquatic plant biomass of the model river patch decreased below the aquatic plant biomass of the river outside the model. Reducing the initial aquatic plant biomass of the model river patch reduced depletion to 0 g DM m−2 as swans emigrated on the first time step and thus did not feed inside the model (Figure 3). In contrast, increasing the initial biomass within the model river patch increased depletion, as emigration was delayed due to the greater biomass. Depletion reached 200 g DM m−2 for a 100% increase in aquatic plant biomass inside the model river patch. Reduced biomass in the river outside the model increased depletion within the model, up to a maximum of 70 g DM m−2 for ≥−40% change.

Bottom Line: However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement.New methods which address these issues and offer effective wildlife management are required.The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems.

View Article: PubMed Central - PubMed

Affiliation: Centre for Ecology and Hydrology, Edinburgh, United Kingdom; Faculty of Science & Technology, Bournemouth University, Dorset, United Kingdom.

ABSTRACT
Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems.

Show MeSH
Related in: MedlinePlus