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Can wild ungulate carcasses provide enough biomass to maintain avian scavenger populations? An empirical assessment using a bio-inspired computational model.

Margalida A, Colomer MÀ, Sanuy D - PLoS ONE (2011)

Bottom Line: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics.We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available.Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

View Article: PubMed Central - PubMed

Affiliation: Bearded Vulture Study and Protection Group, El Pont de Suert Lleida, Spain. margalida@inf.entorno.es

ABSTRACT

Background: The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of several sanitary regulations has limited the availability of feeding resources provided by domestic carcasses, but theoretical studies assessing whether the availability of food resources provided by wild ungulates are enough to cover energetic requirements are lacking.

Methodology/findings: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics. We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available. Simulation testing of the model suggests that wild ungulates constitute an important food resource in the Pyrenees and the vulture population inhabiting this area could grow if only the food provided by wild ungulates would be available. On the contrary, in the Pre-Pyrenees there is insufficient food to cover the energy requirements of avian scavenger guilds, declining sharply if biomass from domestic animals would not be available.

Conclusions/significance: Our results suggest that public health legislation can modify scavenger population trends if a large number of domestic ungulate carcasses disappear from the mountains. In this case, food provided by wild ungulates could be not enough and supplementary feeding could be necessary if other alternative food resources are not available (i.e. the reintroduction of wild ungulates), preferably in European Mediterranean scenarios sharing similar and socio-economic conditions where there are low densities of wild ungulates. Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

Show MeSH
Hypothetical population trend and 95% confidence intervals of the three avian scavengers in the two subpopulations studied.a) represents a hypothetical scenario in which food obtained by the scavengers was only provided by wild ungulates) while b) represents the results obtained by the model under the real scenario during 1994–2009. The starting point (0) is the population of every species in the year 1994. Zone 1): Pyrenees; Zone 2): Pre-Pyrenees.
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pone-0020248-g003: Hypothetical population trend and 95% confidence intervals of the three avian scavengers in the two subpopulations studied.a) represents a hypothetical scenario in which food obtained by the scavengers was only provided by wild ungulates) while b) represents the results obtained by the model under the real scenario during 1994–2009. The starting point (0) is the population of every species in the year 1994. Zone 1): Pyrenees; Zone 2): Pre-Pyrenees.

Mentions: As shown in Figure 3, in the Pyrenees the increase in the guild of avian scavengers would not have been affected if they had only access to food provided by wild ungulates (Figure 3a). With regards to the population growth in the real scenario, no significant differences were found in any of the species considered (P>0.05 for all species, Figure 3a). The average growth of the bearded vulture population with wild ungulates only was 5±5%, for the Egyptian vulture 8±4% and for the griffon vulture 10±14%.


Can wild ungulate carcasses provide enough biomass to maintain avian scavenger populations? An empirical assessment using a bio-inspired computational model.

Margalida A, Colomer MÀ, Sanuy D - PLoS ONE (2011)

Hypothetical population trend and 95% confidence intervals of the three avian scavengers in the two subpopulations studied.a) represents a hypothetical scenario in which food obtained by the scavengers was only provided by wild ungulates) while b) represents the results obtained by the model under the real scenario during 1994–2009. The starting point (0) is the population of every species in the year 1994. Zone 1): Pyrenees; Zone 2): Pre-Pyrenees.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3101228&req=5

pone-0020248-g003: Hypothetical population trend and 95% confidence intervals of the three avian scavengers in the two subpopulations studied.a) represents a hypothetical scenario in which food obtained by the scavengers was only provided by wild ungulates) while b) represents the results obtained by the model under the real scenario during 1994–2009. The starting point (0) is the population of every species in the year 1994. Zone 1): Pyrenees; Zone 2): Pre-Pyrenees.
Mentions: As shown in Figure 3, in the Pyrenees the increase in the guild of avian scavengers would not have been affected if they had only access to food provided by wild ungulates (Figure 3a). With regards to the population growth in the real scenario, no significant differences were found in any of the species considered (P>0.05 for all species, Figure 3a). The average growth of the bearded vulture population with wild ungulates only was 5±5%, for the Egyptian vulture 8±4% and for the griffon vulture 10±14%.

Bottom Line: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics.We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available.Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

View Article: PubMed Central - PubMed

Affiliation: Bearded Vulture Study and Protection Group, El Pont de Suert Lleida, Spain. margalida@inf.entorno.es

ABSTRACT

Background: The reduction in the amount of food available for European avian scavengers as a consequence of restrictive public health policies is a concern for managers and conservationists. Since 2002, the application of several sanitary regulations has limited the availability of feeding resources provided by domestic carcasses, but theoretical studies assessing whether the availability of food resources provided by wild ungulates are enough to cover energetic requirements are lacking.

Methodology/findings: We assessed food provided by a wild ungulate population in two areas of NE Spain inhabited by three vulture species and developed a P System computational model to assess the effects of the carrion resources provided on their population dynamics. We compared the real population trend with to a hypothetical scenario in which only food provided by wild ungulates was available. Simulation testing of the model suggests that wild ungulates constitute an important food resource in the Pyrenees and the vulture population inhabiting this area could grow if only the food provided by wild ungulates would be available. On the contrary, in the Pre-Pyrenees there is insufficient food to cover the energy requirements of avian scavenger guilds, declining sharply if biomass from domestic animals would not be available.

Conclusions/significance: Our results suggest that public health legislation can modify scavenger population trends if a large number of domestic ungulate carcasses disappear from the mountains. In this case, food provided by wild ungulates could be not enough and supplementary feeding could be necessary if other alternative food resources are not available (i.e. the reintroduction of wild ungulates), preferably in European Mediterranean scenarios sharing similar and socio-economic conditions where there are low densities of wild ungulates. Managers should anticipate the conservation actions required by assessing food availability and the possible scenarios in order to make the most suitable decisions.

Show MeSH