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The dual role of rivers in facilitating or hindering movements of the false heath fritillary butterfly.

Fabritius H, Rönkä K, Ovaskainen O - Mov Ecol (2015)

Bottom Line: The riparian population of the false heath fritillary did not show major differences to reference populations in terms of movement parameters within breeding habitat, high-quality matrix and low-quality matrix.An artificial riparian landscape mimicking those of the coastal distribution resulted into more directional, longitudinal movements both parallel and perpendicular to the river than a more mosaic-like landscape, but the existence of the river in the landscape reduced movements across the river.As such, they can be used to compare movement parameters across populations, to study the effects of management interventions to endangered species and to identify areas that have high sensitivity to individual movement.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014 Helsinki, Finland.

ABSTRACT

Background: Species movement responses to landscape structures have been studied using a variety of methods, but movement research is still in need of simple methods that help predicting and comparing movements across structurally different landscapes. We demonstrate how habitat-specific movement models can be used to disentangle causes of differentiated movement patterns in structurally different landscapes and to predict movement patterns in altered and artificial landscapes. In our case study, we studied the role of riparian landscapes to the persistence of the endangered false heath fritillary butterfly (Melitaea diamina) in its newly discovered coastal distribution region in Finland. We compared the movement parameters of the riparian population to two reference populations by using capture-recapture data and habitat-specific diffusion modelling, and analysed the role of the river and riverbank buffer zones in facilitating or hindering false heath fritillary movement with movement simulations.

Results: The riparian population of the false heath fritillary did not show major differences to reference populations in terms of movement parameters within breeding habitat, high-quality matrix and low-quality matrix. However, movement simulations showed that the habitat-specific movement parameters estimated for the false heath fritillary can lead into markedly different movement patterns in structurally different landscapes. An artificial riparian landscape mimicking those of the coastal distribution resulted into more directional, longitudinal movements both parallel and perpendicular to the river than a more mosaic-like landscape, but the existence of the river in the landscape reduced movements across the river.

Conclusions: Our study demonstrates how habitat-specific movement models enable comparisons of movement patterns across structurally different real, altered and artificial landscapes. As such, they can be used to compare movement parameters across populations, to study the effects of management interventions to endangered species and to identify areas that have high sensitivity to individual movement. In our case study, the river is shown to perform a dual role for the movements of the riparian false heath fritillary population. Whereas the river acts as a moderate movement barrier for the false heath fritillary, the longitudinal configuration of riverbank habitats provides a means especially for the male false heath fritillaries to move across the landscape.

No MeSH data available.


The effect of the river and riverbank habitats to the movements of the false heath fritillary in a hypothetical landscape. The graph shows probability of simulated male (middle column of panels) and female (right hand column of panels) false heath fritillaries to reach a target patch (light blue edges; pointed with an arrow, located on the Western side of the river) within its lifetime, as a function of its place of birth. The results are shown for a landscape with a 50-meter wide low-quality matrix stripe (the river) and symmetric riverbank habitats (panels D-F), a similar landscape in which the river has been replaced with breeding habitat (panels G-I) and for a landscape where the same amount of habitat (in squares) and low-quality matrix as in the artificial riparian landscape has been distributed evenly across the landscape (panels A-C). Parameter values set to the posterior median values of the generalised movement model. We classified the landscapes (panels A, D, G) into low-quality matrix (dark grey) and breeding habitat (white).
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Fig6: The effect of the river and riverbank habitats to the movements of the false heath fritillary in a hypothetical landscape. The graph shows probability of simulated male (middle column of panels) and female (right hand column of panels) false heath fritillaries to reach a target patch (light blue edges; pointed with an arrow, located on the Western side of the river) within its lifetime, as a function of its place of birth. The results are shown for a landscape with a 50-meter wide low-quality matrix stripe (the river) and symmetric riverbank habitats (panels D-F), a similar landscape in which the river has been replaced with breeding habitat (panels G-I) and for a landscape where the same amount of habitat (in squares) and low-quality matrix as in the artificial riparian landscape has been distributed evenly across the landscape (panels A-C). Parameter values set to the posterior median values of the generalised movement model. We classified the landscapes (panels A, D, G) into low-quality matrix (dark grey) and breeding habitat (white).

Mentions: Movement simulations carried out using three artificial landscapes (Figure 6) demonstrate how different landscape elements interplay to inhibit or facilitate false heath fritillary movements in a riparian landscape. First, we compare false heath fritillary movement patterns between a riparian landscape consisting of a low-quality matrix river and symmetric riverbank habitats (Figure 6, panels D-F), and a control landscape where an equal amount of habitat and low-quality matrix is distributed evenly across the landscape (panels A-C). For male false heath fritillaries, the probabilities of hitting a target patch both from the North (parallel to the river) and from the East and West (perpendicular to the river) are higher in the riparian landscape than in a control landscape (Figure 7, panels C-D). Long directional movements perpendicular to the river occur due to the absence of habitat patches in the surrounding landscape, causing the males to fly fast across the low-quality matrix (DLQM) while searching for habitat patches. If habitat patches are distributed evenly across the landscape, males are likely to stop at habitat patches and may change direction when leaving a patch. Long directional movements parallel to the river are co-products of relatively high movement rates in, and a high preference of, the breeding habitat (DBH and kBH). For female false heath fritillaries, differences in movement patterns are otherwise similar to those of males, except that probabilities of hitting a target patch from the North (parallel to the river) are not higher in the riparian landscape than in the control landscape due to lower estimated movement rates in the breeding habitat (DBH, Figure 8). Hitting probabilities diagonal to the river are likely to be higher than those parallel to the river for females (Figure 6, panel F).Figure 6


The dual role of rivers in facilitating or hindering movements of the false heath fritillary butterfly.

Fabritius H, Rönkä K, Ovaskainen O - Mov Ecol (2015)

The effect of the river and riverbank habitats to the movements of the false heath fritillary in a hypothetical landscape. The graph shows probability of simulated male (middle column of panels) and female (right hand column of panels) false heath fritillaries to reach a target patch (light blue edges; pointed with an arrow, located on the Western side of the river) within its lifetime, as a function of its place of birth. The results are shown for a landscape with a 50-meter wide low-quality matrix stripe (the river) and symmetric riverbank habitats (panels D-F), a similar landscape in which the river has been replaced with breeding habitat (panels G-I) and for a landscape where the same amount of habitat (in squares) and low-quality matrix as in the artificial riparian landscape has been distributed evenly across the landscape (panels A-C). Parameter values set to the posterior median values of the generalised movement model. We classified the landscapes (panels A, D, G) into low-quality matrix (dark grey) and breeding habitat (white).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4940950&req=5

Fig6: The effect of the river and riverbank habitats to the movements of the false heath fritillary in a hypothetical landscape. The graph shows probability of simulated male (middle column of panels) and female (right hand column of panels) false heath fritillaries to reach a target patch (light blue edges; pointed with an arrow, located on the Western side of the river) within its lifetime, as a function of its place of birth. The results are shown for a landscape with a 50-meter wide low-quality matrix stripe (the river) and symmetric riverbank habitats (panels D-F), a similar landscape in which the river has been replaced with breeding habitat (panels G-I) and for a landscape where the same amount of habitat (in squares) and low-quality matrix as in the artificial riparian landscape has been distributed evenly across the landscape (panels A-C). Parameter values set to the posterior median values of the generalised movement model. We classified the landscapes (panels A, D, G) into low-quality matrix (dark grey) and breeding habitat (white).
Mentions: Movement simulations carried out using three artificial landscapes (Figure 6) demonstrate how different landscape elements interplay to inhibit or facilitate false heath fritillary movements in a riparian landscape. First, we compare false heath fritillary movement patterns between a riparian landscape consisting of a low-quality matrix river and symmetric riverbank habitats (Figure 6, panels D-F), and a control landscape where an equal amount of habitat and low-quality matrix is distributed evenly across the landscape (panels A-C). For male false heath fritillaries, the probabilities of hitting a target patch both from the North (parallel to the river) and from the East and West (perpendicular to the river) are higher in the riparian landscape than in a control landscape (Figure 7, panels C-D). Long directional movements perpendicular to the river occur due to the absence of habitat patches in the surrounding landscape, causing the males to fly fast across the low-quality matrix (DLQM) while searching for habitat patches. If habitat patches are distributed evenly across the landscape, males are likely to stop at habitat patches and may change direction when leaving a patch. Long directional movements parallel to the river are co-products of relatively high movement rates in, and a high preference of, the breeding habitat (DBH and kBH). For female false heath fritillaries, differences in movement patterns are otherwise similar to those of males, except that probabilities of hitting a target patch from the North (parallel to the river) are not higher in the riparian landscape than in the control landscape due to lower estimated movement rates in the breeding habitat (DBH, Figure 8). Hitting probabilities diagonal to the river are likely to be higher than those parallel to the river for females (Figure 6, panel F).Figure 6

Bottom Line: The riparian population of the false heath fritillary did not show major differences to reference populations in terms of movement parameters within breeding habitat, high-quality matrix and low-quality matrix.An artificial riparian landscape mimicking those of the coastal distribution resulted into more directional, longitudinal movements both parallel and perpendicular to the river than a more mosaic-like landscape, but the existence of the river in the landscape reduced movements across the river.As such, they can be used to compare movement parameters across populations, to study the effects of management interventions to endangered species and to identify areas that have high sensitivity to individual movement.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014 Helsinki, Finland.

ABSTRACT

Background: Species movement responses to landscape structures have been studied using a variety of methods, but movement research is still in need of simple methods that help predicting and comparing movements across structurally different landscapes. We demonstrate how habitat-specific movement models can be used to disentangle causes of differentiated movement patterns in structurally different landscapes and to predict movement patterns in altered and artificial landscapes. In our case study, we studied the role of riparian landscapes to the persistence of the endangered false heath fritillary butterfly (Melitaea diamina) in its newly discovered coastal distribution region in Finland. We compared the movement parameters of the riparian population to two reference populations by using capture-recapture data and habitat-specific diffusion modelling, and analysed the role of the river and riverbank buffer zones in facilitating or hindering false heath fritillary movement with movement simulations.

Results: The riparian population of the false heath fritillary did not show major differences to reference populations in terms of movement parameters within breeding habitat, high-quality matrix and low-quality matrix. However, movement simulations showed that the habitat-specific movement parameters estimated for the false heath fritillary can lead into markedly different movement patterns in structurally different landscapes. An artificial riparian landscape mimicking those of the coastal distribution resulted into more directional, longitudinal movements both parallel and perpendicular to the river than a more mosaic-like landscape, but the existence of the river in the landscape reduced movements across the river.

Conclusions: Our study demonstrates how habitat-specific movement models enable comparisons of movement patterns across structurally different real, altered and artificial landscapes. As such, they can be used to compare movement parameters across populations, to study the effects of management interventions to endangered species and to identify areas that have high sensitivity to individual movement. In our case study, the river is shown to perform a dual role for the movements of the riparian false heath fritillary population. Whereas the river acts as a moderate movement barrier for the false heath fritillary, the longitudinal configuration of riverbank habitats provides a means especially for the male false heath fritillaries to move across the landscape.

No MeSH data available.