Limits...
Satellite tracking of sympatric marine megafauna can inform the biological basis for species co-management.

Gredzens C, Marsh H, Fuentes MM, Limpus CJ, Shimada T, Hamann M - PLoS ONE (2014)

Bottom Line: Additionally, sympatric and inter-related species are often managed separately, which may not be cost-effective.Home-range analysis and bathymetric modeling were used to determine spatial use and compared with existing protection areas using GIS.Dugong and green turtle home-ranges significantly overlapped in both locations.

View Article: PubMed Central - PubMed

Affiliation: School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia; School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.

ABSTRACT

Context: Systematic conservation planning is increasingly used to identify priority areas for protection in marine systems. However, ecosystem-based approaches typically use density estimates as surrogates for animal presence and spatial modeling to identify areas for protection and may not take into account daily or seasonal movements of animals. Additionally, sympatric and inter-related species are often managed separately, which may not be cost-effective. This study aims to demonstrate an evidence-based method to inform the biological basis for co-management of two sympatric species, dugongs and green sea turtles. This approach can then be used in conservation planning to delineate areas to maximize species protection.

Methodology/results: Fast-acquisition satellite telemetry was used to track eleven dugongs and ten green turtles at two geographically distinct foraging locations in Queensland, Australia to evaluate the inter- and intra-species spatial relationships and assess the efficacy of existing protection zones. Home-range analysis and bathymetric modeling were used to determine spatial use and compared with existing protection areas using GIS. Dugong and green turtle home-ranges significantly overlapped in both locations. However, both species used different core areas and differences existed between regions in depth zone use and home-range size, especially for dugongs. Both species used existing protection areas in Shoalwater Bay, but only a single tracked dugong used the existing protection area in Torres Strait.

Conclusions/significance: Fast-acquisition satellite telemetry can provide evidence-based information on individual animal movements to delineate relationships between dugongs and green turtles in regions where they co-occur. This information can be used to increase the efficacy of conservation planning and complement more broadly based survey information. These species also use similar habitats, making complimentary co-management possible, but important differences exist between locations making it essential to customize management. This methodology could be applied on a broader scale to include other sympatric and inter-related species.

Show MeSH
Depth zone use of tracked dugongs and green turtles.Depth comparison of 95% home-ranges and 50% core areas between Shoalwater Bay, Australia dugongs (n = 5), green sea turtles (n = 6), and a transient dugong (n = 1) (top) with Torres Strait, Australia dugongs (n = 6), reef associated green sea turtles (n = 3), and a transient green sea turtle (n = 1) (bottom).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4043907&req=5

pone-0098944-g004: Depth zone use of tracked dugongs and green turtles.Depth comparison of 95% home-ranges and 50% core areas between Shoalwater Bay, Australia dugongs (n = 5), green sea turtles (n = 6), and a transient dugong (n = 1) (top) with Torres Strait, Australia dugongs (n = 6), reef associated green sea turtles (n = 3), and a transient green sea turtle (n = 1) (bottom).

Mentions: Within Shoalwater Bay, the tracked dugongs and turtles frequented shallow water areas between 0–5 m (Figure 4). Turtles were found almost exclusively in intertidal areas with all core areas found in depth zones less than 5 m and over tidal flats, within mangrove zones, or up tidal creeks (Figure 2D,F). Only three turtles (108469, 108472, and 120641) had 95% home-ranges extending over regions >5 m in depth and these deeper areas accounted for only a small percentage of their ranges (mean  = 8.3%, SE  = 4.6%). No turtles were found in waters >10 m deep. Resident dugongs were found predominantly in subtidal zones with around 80% of their 95% and 50% ranges found in depth zones between 0–5 m (Figure 4). The remainder of the dugong ranges were in the 5–10 m zone; some individuals occasionally ventured over deeper areas up to a maximum of 20 m in depth. The transient dugong (652636A – female) was found over a range of depth zones between 0–20 m, with roughly equal portions of its range found over each 5 m depth zone (Figure 4). None of the dugongs had core areas over the tidal flats preferred by turtles (Figure 2F). There were no diurnal differences in the depth preferences of dugongs or turtles in Shoalwater Bay.


Satellite tracking of sympatric marine megafauna can inform the biological basis for species co-management.

Gredzens C, Marsh H, Fuentes MM, Limpus CJ, Shimada T, Hamann M - PLoS ONE (2014)

Depth zone use of tracked dugongs and green turtles.Depth comparison of 95% home-ranges and 50% core areas between Shoalwater Bay, Australia dugongs (n = 5), green sea turtles (n = 6), and a transient dugong (n = 1) (top) with Torres Strait, Australia dugongs (n = 6), reef associated green sea turtles (n = 3), and a transient green sea turtle (n = 1) (bottom).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043907&req=5

pone-0098944-g004: Depth zone use of tracked dugongs and green turtles.Depth comparison of 95% home-ranges and 50% core areas between Shoalwater Bay, Australia dugongs (n = 5), green sea turtles (n = 6), and a transient dugong (n = 1) (top) with Torres Strait, Australia dugongs (n = 6), reef associated green sea turtles (n = 3), and a transient green sea turtle (n = 1) (bottom).
Mentions: Within Shoalwater Bay, the tracked dugongs and turtles frequented shallow water areas between 0–5 m (Figure 4). Turtles were found almost exclusively in intertidal areas with all core areas found in depth zones less than 5 m and over tidal flats, within mangrove zones, or up tidal creeks (Figure 2D,F). Only three turtles (108469, 108472, and 120641) had 95% home-ranges extending over regions >5 m in depth and these deeper areas accounted for only a small percentage of their ranges (mean  = 8.3%, SE  = 4.6%). No turtles were found in waters >10 m deep. Resident dugongs were found predominantly in subtidal zones with around 80% of their 95% and 50% ranges found in depth zones between 0–5 m (Figure 4). The remainder of the dugong ranges were in the 5–10 m zone; some individuals occasionally ventured over deeper areas up to a maximum of 20 m in depth. The transient dugong (652636A – female) was found over a range of depth zones between 0–20 m, with roughly equal portions of its range found over each 5 m depth zone (Figure 4). None of the dugongs had core areas over the tidal flats preferred by turtles (Figure 2F). There were no diurnal differences in the depth preferences of dugongs or turtles in Shoalwater Bay.

Bottom Line: Additionally, sympatric and inter-related species are often managed separately, which may not be cost-effective.Home-range analysis and bathymetric modeling were used to determine spatial use and compared with existing protection areas using GIS.Dugong and green turtle home-ranges significantly overlapped in both locations.

View Article: PubMed Central - PubMed

Affiliation: School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia; School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.

ABSTRACT

Context: Systematic conservation planning is increasingly used to identify priority areas for protection in marine systems. However, ecosystem-based approaches typically use density estimates as surrogates for animal presence and spatial modeling to identify areas for protection and may not take into account daily or seasonal movements of animals. Additionally, sympatric and inter-related species are often managed separately, which may not be cost-effective. This study aims to demonstrate an evidence-based method to inform the biological basis for co-management of two sympatric species, dugongs and green sea turtles. This approach can then be used in conservation planning to delineate areas to maximize species protection.

Methodology/results: Fast-acquisition satellite telemetry was used to track eleven dugongs and ten green turtles at two geographically distinct foraging locations in Queensland, Australia to evaluate the inter- and intra-species spatial relationships and assess the efficacy of existing protection zones. Home-range analysis and bathymetric modeling were used to determine spatial use and compared with existing protection areas using GIS. Dugong and green turtle home-ranges significantly overlapped in both locations. However, both species used different core areas and differences existed between regions in depth zone use and home-range size, especially for dugongs. Both species used existing protection areas in Shoalwater Bay, but only a single tracked dugong used the existing protection area in Torres Strait.

Conclusions/significance: Fast-acquisition satellite telemetry can provide evidence-based information on individual animal movements to delineate relationships between dugongs and green turtles in regions where they co-occur. This information can be used to increase the efficacy of conservation planning and complement more broadly based survey information. These species also use similar habitats, making complimentary co-management possible, but important differences exist between locations making it essential to customize management. This methodology could be applied on a broader scale to include other sympatric and inter-related species.

Show MeSH