The protection of marine megafauna within Europe is rather fragmented. Developing conservation measures for highly mobile species presents definite challenges, particularly due to the many knowledge gaps. Recent studi...The protection of marine megafauna within Europe is rather fragmented. Developing conservation measures for highly mobile species presents definite challenges, particularly due to the many knowledge gaps. Recent studies have shown that these gaps can be filled in by Platforms of Opportunity (PO) which create low-cost approaches. However, the number of wildlife tour operators actively collecting PO data related to distribution and relative abundance of marine fauna remains limited. In this study, we investigated whether effort-corrected data on marine megafauna facilitated by a wildlife tour operator afforded robust long temporal data (2011-2015). Sightings data, collected in the wider Mount’s Bay area (southwest Cornwall, UK), along with a GPS application, were collected to accurately record survey effort. In addition, radial sighting distances and detection curves were computed to explore the robustness of the data. Density maps of marine megafauna indicated that encounters occurred throughout the area in all three seasons but the temporal distribution was significantly different with numbers peaking in autumn. Odontocetes were mostly recorded during autumn, basking shark (Cetorhinus maximus) and ocean sunfish (Mola mola) were more abundant during summer and leatherback turtles (Dermochelys coriacea) were recorded occasionally. Our data showed that this shallow coastal environment is particularly important as a nursing area for harbour porpoises (Phocoena phocoena). Risso’s dolphins (Grampus griseus) showed a high semi-residency pattern for adults with calves within one core-habitat. As such, the study provides important spatial and temporal baseline data that are essential for the protection of marine megafauna through the development of an ecological network of marine protected areas within UK waters. Although, data facilitated by wildlife operators have certain shortcomings we highlight that the protocols developed here secured efficient and precise data. Such collection protocols can be implemented on a larger scale, ultimately enhancing research monitoring efforts and marine ecosystem management.展开更多
The Patagonian Sea is one of the most productive ecosystems in the Southern Hemisphere. Unlike other coastal regions, however, few studies exist on the top predators in its pelagic zone. In March 2017, a survey of sea...The Patagonian Sea is one of the most productive ecosystems in the Southern Hemisphere. Unlike other coastal regions, however, few studies exist on the top predators in its pelagic zone. In March 2017, a survey of seabirds and marine mammals was carried out on board the R/V Puerto Deseado in the Patagonian Sea, which extends from the South Atlantic Ocean to the north of the South Orkney Islands, Antarctica. Four of the five oceanographic regimes described in this region were studied, and 23 seabird species and five marine mammal species were recorded. Great shearwater Puffinus gravis, Antarctic prion Pachyptila desolata, and fin whale Balaenoptera physalus were the most abundant species. In the 2615 km traveled, two hotspots for top predators were found, coinciding with frontal zones: one in the shelf-break front and the other in the Southern Front of the Antarctic Circumpolar Current. The highest bird diversity and the greatest cetacean concentrations were recorded in the polar regime in the presence of low ice-field debris(5%). The results suggest that at the end of the austral summer, the distribution of top predators in this section of the South Atlantic Ocean is highly unequal. Some oceanic areas have a few species aggregations which contrast with the vast pelagic areas that have scarce species presence and activity. The hotspots were associated with high-productivity areas, but it is likely that they were also facilitated by the time of year(post-reproductive season), as most of the species were concentrated and had fed prior to their migrations.展开更多
Current palaeoclimatic reconstructions for the R＆#237;o de la Plata region during the latest Pleistocene （30,000 e10,000 yr BP） propose dry conditions, with rainfall at the Last Glacial Maximum amounting to one-thi...Current palaeoclimatic reconstructions for the R＆#237;o de la Plata region during the latest Pleistocene （30,000 e10,000 yr BP） propose dry conditions, with rainfall at the Last Glacial Maximum amounting to one-third of today＇s precipitation. Despite the consequential low primary productivity inferred, an impressive megafauna existed in the area at that time. Here we explore the influence of the flooding from a huge extinct system of water bodies in the Andean Altiplano as a likely source for wet regimes that might have increased the primary productivity and, hence, the vast number of megaherbivores. The system was reconstructed using specifically combined software resources, including Insola, Global Mapper v13, Surfer and Matlab. Changes in water volume and area covered were related to climatic change, assessed through a model of astronomical forcing that describes the changes in insolation at the top of the at-mosphere in the last 50,000 yr BP. The model was validated by comparing its results with several proxies （CH4, CO2, D, 18O） from dated cores taken from the ice covering Antarctic lakes Vostok and EPICA Dome C. It is concluded that the Altiplano Lake system drained towards the southeast in the rainy seasons and that it must have been a major source of water for the Paran＆#225;-Plata Basin, consequently enhancing primary productivity within it.展开更多
文摘The protection of marine megafauna within Europe is rather fragmented. Developing conservation measures for highly mobile species presents definite challenges, particularly due to the many knowledge gaps. Recent studies have shown that these gaps can be filled in by Platforms of Opportunity (PO) which create low-cost approaches. However, the number of wildlife tour operators actively collecting PO data related to distribution and relative abundance of marine fauna remains limited. In this study, we investigated whether effort-corrected data on marine megafauna facilitated by a wildlife tour operator afforded robust long temporal data (2011-2015). Sightings data, collected in the wider Mount’s Bay area (southwest Cornwall, UK), along with a GPS application, were collected to accurately record survey effort. In addition, radial sighting distances and detection curves were computed to explore the robustness of the data. Density maps of marine megafauna indicated that encounters occurred throughout the area in all three seasons but the temporal distribution was significantly different with numbers peaking in autumn. Odontocetes were mostly recorded during autumn, basking shark (Cetorhinus maximus) and ocean sunfish (Mola mola) were more abundant during summer and leatherback turtles (Dermochelys coriacea) were recorded occasionally. Our data showed that this shallow coastal environment is particularly important as a nursing area for harbour porpoises (Phocoena phocoena). Risso’s dolphins (Grampus griseus) showed a high semi-residency pattern for adults with calves within one core-habitat. As such, the study provides important spatial and temporal baseline data that are essential for the protection of marine megafauna through the development of an ecological network of marine protected areas within UK waters. Although, data facilitated by wildlife operators have certain shortcomings we highlight that the protocols developed here secured efficient and precise data. Such collection protocols can be implemented on a larger scale, ultimately enhancing research monitoring efforts and marine ecosystem management.
基金financial support from the Instituto Antártico Argentino
文摘The Patagonian Sea is one of the most productive ecosystems in the Southern Hemisphere. Unlike other coastal regions, however, few studies exist on the top predators in its pelagic zone. In March 2017, a survey of seabirds and marine mammals was carried out on board the R/V Puerto Deseado in the Patagonian Sea, which extends from the South Atlantic Ocean to the north of the South Orkney Islands, Antarctica. Four of the five oceanographic regimes described in this region were studied, and 23 seabird species and five marine mammal species were recorded. Great shearwater Puffinus gravis, Antarctic prion Pachyptila desolata, and fin whale Balaenoptera physalus were the most abundant species. In the 2615 km traveled, two hotspots for top predators were found, coinciding with frontal zones: one in the shelf-break front and the other in the Southern Front of the Antarctic Circumpolar Current. The highest bird diversity and the greatest cetacean concentrations were recorded in the polar regime in the presence of low ice-field debris(5%). The results suggest that at the end of the austral summer, the distribution of top predators in this section of the South Atlantic Ocean is highly unequal. Some oceanic areas have a few species aggregations which contrast with the vast pelagic areas that have scarce species presence and activity. The hotspots were associated with high-productivity areas, but it is likely that they were also facilitated by the time of year(post-reproductive season), as most of the species were concentrated and had fed prior to their migrations.
文摘Current palaeoclimatic reconstructions for the R＆#237;o de la Plata region during the latest Pleistocene （30,000 e10,000 yr BP） propose dry conditions, with rainfall at the Last Glacial Maximum amounting to one-third of today＇s precipitation. Despite the consequential low primary productivity inferred, an impressive megafauna existed in the area at that time. Here we explore the influence of the flooding from a huge extinct system of water bodies in the Andean Altiplano as a likely source for wet regimes that might have increased the primary productivity and, hence, the vast number of megaherbivores. The system was reconstructed using specifically combined software resources, including Insola, Global Mapper v13, Surfer and Matlab. Changes in water volume and area covered were related to climatic change, assessed through a model of astronomical forcing that describes the changes in insolation at the top of the at-mosphere in the last 50,000 yr BP. The model was validated by comparing its results with several proxies （CH4, CO2, D, 18O） from dated cores taken from the ice covering Antarctic lakes Vostok and EPICA Dome C. It is concluded that the Altiplano Lake system drained towards the southeast in the rainy seasons and that it must have been a major source of water for the Paran＆#225;-Plata Basin, consequently enhancing primary productivity within it.
