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Survival in patchy landscapes: the interplay between dispersal, habitat loss and fragmentation.

Niebuhr BB, Wosniack ME, Santos MC, Raposo EP, Viswanathan GM, da Luz MG, Pie MR - Sci Rep (2015)

Bottom Line: Such landscape changes can lead to the deleterious impact of a significant drop in the number of species, caused by critically reduced survival rates for organisms.By considering basic ecological processes, such as predation, starvation (outside the habitat area), and competition, together with dispersal movement as a link among habitat areas, we show that a higher survival rate is achieved in instances with a lower number of patches of larger areas.In particular, they have important implications for conservation planning and ecosystem management, including the design of specific features of conservation areas in order to enhance landscape connectivity and population viability.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, CP 19020, 81531-980, Curitiba-PR, Brazil.

ABSTRACT
Habitat loss and fragmentation are important factors determining animal population dynamics and spatial distribution. Such landscape changes can lead to the deleterious impact of a significant drop in the number of species, caused by critically reduced survival rates for organisms. In order to obtain a deeper understanding of the threeway interplay between habitat loss, fragmentation and survival rates, we propose here a spatially explicit multi-scaled movement model of individuals that search for habitat. By considering basic ecological processes, such as predation, starvation (outside the habitat area), and competition, together with dispersal movement as a link among habitat areas, we show that a higher survival rate is achieved in instances with a lower number of patches of larger areas. Our results demonstrate how movement may counterbalance the effects of habitat loss and fragmentation in altered landscapes. In particular, they have important implications for conservation planning and ecosystem management, including the design of specific features of conservation areas in order to enhance landscape connectivity and population viability.

No MeSH data available.


Related in: MedlinePlus

(A) Individual survival rate Γ as a function of μ for distinct fragmentation levels and total habitat amount AH/AT = 30%. The inset shows the difference between the cases with AH = 30% of AT and AH = 10% of AT. (B) Variation of Γ with the fragmentation level (represented by the number of patches in which a fixed habitat amount is divided, Np) and habitat amount for three distinct diffusive classes of searchers: a nearly-ballistic searcher (μ = 1.1), a superdiffusive searcher (μ = 2), and a Brownian searcher (μ = 3). Note that survival decreases for less diffusive searchers (higher μ) and more fragmented landscape (higher Np). For animals with very low dispersal capacity (μ ≥ 2.7), survival is possible only when fragmentation is absent (Np = 1).
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f2: (A) Individual survival rate Γ as a function of μ for distinct fragmentation levels and total habitat amount AH/AT = 30%. The inset shows the difference between the cases with AH = 30% of AT and AH = 10% of AT. (B) Variation of Γ with the fragmentation level (represented by the number of patches in which a fixed habitat amount is divided, Np) and habitat amount for three distinct diffusive classes of searchers: a nearly-ballistic searcher (μ = 1.1), a superdiffusive searcher (μ = 2), and a Brownian searcher (μ = 3). Note that survival decreases for less diffusive searchers (higher μ) and more fragmented landscape (higher Np). For animals with very low dispersal capacity (μ ≥ 2.7), survival is possible only when fragmentation is absent (Np = 1).

Mentions: Fig. 2A shows a plot of the survival rate Γ versus dispersal strategy parameter μ for the total habitat area AH equal to 30% of the landscape size AT and distinct numbers Np of patches. In the inset we show the difference between Γ for habitat area consisting of 30% of AT and 10% of AT. Notice that the animal survival is boosted as the total amount of habitat increases. Furthermore, as seen in Fig. 2A, the increase in μ and in the number of patches (with Np > 1 and AH kept fixed) decreases Γ. This decrease in Γ caused by habitat loss, fragmentation and degree of diffusiveness is illustrated in Fig. 2B. The negative impact of habitat fragmentation only (i.e., with both the total amount of habitat AH and diffusivity μ fixed) is enhanced for smaller AH’s and larger μ’s. For example, the difference in survivals for AH = 0.1AT and AH = 0.3AT when Np = 5 and Np = 50 are, respectively, (a) μ = 1.1: 48% and 80%; and (b) μ = 2: 85% and 98%. For animals having a low dispersal rate (μ ≈ 3), any amount of habitat fragmentation already can cause a strong impact on survival rate. Indeed, for small AH/AT, the fragmentation of the habitat into 5 patches basically makes no individual able to survive. Hence, even a low level of fragmentation yields drastic changes in the survival when μ ≥ 2 (a situation which is true for distinct animal species2225).


Survival in patchy landscapes: the interplay between dispersal, habitat loss and fragmentation.

Niebuhr BB, Wosniack ME, Santos MC, Raposo EP, Viswanathan GM, da Luz MG, Pie MR - Sci Rep (2015)

(A) Individual survival rate Γ as a function of μ for distinct fragmentation levels and total habitat amount AH/AT = 30%. The inset shows the difference between the cases with AH = 30% of AT and AH = 10% of AT. (B) Variation of Γ with the fragmentation level (represented by the number of patches in which a fixed habitat amount is divided, Np) and habitat amount for three distinct diffusive classes of searchers: a nearly-ballistic searcher (μ = 1.1), a superdiffusive searcher (μ = 2), and a Brownian searcher (μ = 3). Note that survival decreases for less diffusive searchers (higher μ) and more fragmented landscape (higher Np). For animals with very low dispersal capacity (μ ≥ 2.7), survival is possible only when fragmentation is absent (Np = 1).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493700&req=5

f2: (A) Individual survival rate Γ as a function of μ for distinct fragmentation levels and total habitat amount AH/AT = 30%. The inset shows the difference between the cases with AH = 30% of AT and AH = 10% of AT. (B) Variation of Γ with the fragmentation level (represented by the number of patches in which a fixed habitat amount is divided, Np) and habitat amount for three distinct diffusive classes of searchers: a nearly-ballistic searcher (μ = 1.1), a superdiffusive searcher (μ = 2), and a Brownian searcher (μ = 3). Note that survival decreases for less diffusive searchers (higher μ) and more fragmented landscape (higher Np). For animals with very low dispersal capacity (μ ≥ 2.7), survival is possible only when fragmentation is absent (Np = 1).
Mentions: Fig. 2A shows a plot of the survival rate Γ versus dispersal strategy parameter μ for the total habitat area AH equal to 30% of the landscape size AT and distinct numbers Np of patches. In the inset we show the difference between Γ for habitat area consisting of 30% of AT and 10% of AT. Notice that the animal survival is boosted as the total amount of habitat increases. Furthermore, as seen in Fig. 2A, the increase in μ and in the number of patches (with Np > 1 and AH kept fixed) decreases Γ. This decrease in Γ caused by habitat loss, fragmentation and degree of diffusiveness is illustrated in Fig. 2B. The negative impact of habitat fragmentation only (i.e., with both the total amount of habitat AH and diffusivity μ fixed) is enhanced for smaller AH’s and larger μ’s. For example, the difference in survivals for AH = 0.1AT and AH = 0.3AT when Np = 5 and Np = 50 are, respectively, (a) μ = 1.1: 48% and 80%; and (b) μ = 2: 85% and 98%. For animals having a low dispersal rate (μ ≈ 3), any amount of habitat fragmentation already can cause a strong impact on survival rate. Indeed, for small AH/AT, the fragmentation of the habitat into 5 patches basically makes no individual able to survive. Hence, even a low level of fragmentation yields drastic changes in the survival when μ ≥ 2 (a situation which is true for distinct animal species2225).

Bottom Line: Such landscape changes can lead to the deleterious impact of a significant drop in the number of species, caused by critically reduced survival rates for organisms.By considering basic ecological processes, such as predation, starvation (outside the habitat area), and competition, together with dispersal movement as a link among habitat areas, we show that a higher survival rate is achieved in instances with a lower number of patches of larger areas.In particular, they have important implications for conservation planning and ecosystem management, including the design of specific features of conservation areas in order to enhance landscape connectivity and population viability.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Dinâmica Evolutiva e Sistemas Complexos, Departamento de Zoologia, Universidade Federal do Paraná, CP 19020, 81531-980, Curitiba-PR, Brazil.

ABSTRACT
Habitat loss and fragmentation are important factors determining animal population dynamics and spatial distribution. Such landscape changes can lead to the deleterious impact of a significant drop in the number of species, caused by critically reduced survival rates for organisms. In order to obtain a deeper understanding of the threeway interplay between habitat loss, fragmentation and survival rates, we propose here a spatially explicit multi-scaled movement model of individuals that search for habitat. By considering basic ecological processes, such as predation, starvation (outside the habitat area), and competition, together with dispersal movement as a link among habitat areas, we show that a higher survival rate is achieved in instances with a lower number of patches of larger areas. Our results demonstrate how movement may counterbalance the effects of habitat loss and fragmentation in altered landscapes. In particular, they have important implications for conservation planning and ecosystem management, including the design of specific features of conservation areas in order to enhance landscape connectivity and population viability.

No MeSH data available.


Related in: MedlinePlus