Browsing by Author "Tierney, Megan"
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- Coastal connectivity of marine predators over the Patagonian Shelf during the highly pathogenic avian influenza outbreakPublication . Riaz, Javed; Orben, Rachael; Gamble, Amandine; Catry, Paulo; Granadeiro, Carlos; Campioni, Letizia; Tierney, Megan; Baylis, AlastairAnimal movement and population connectivity are key areas of uncertainty in efforts to understand and predict the spread of infectious disease. The emergence of highly pathogenic avian influenza (HPAI) in South America poses a significant threat to globally significant populations of colonial breeding marine predators in the South Atlantic. Yet, there is a poor understanding of which species or migratory pathways may facilitate disease spread. Compiling one of the largest available animal tracking datasets in the South Atlantic, we examine connectivity and inter-population mixing for colonial breeding marine predators tagged at the Falkland Islands. We reveal extensive connectivity for three regionally dominant and gregarious species over the Patagonian Shelf. Black-browed albatrosses (BBA), South American fur seals (SAFS) and Magellanic penguins (MAG) used coastal waters along the Atlantic coast of South America (Argentina and Uruguay). These behaviours were recorded at or in close proximity to breeding colonies and haul-out areas with dense aggregations of marine predators. Transit times to and from the Falkland Islands to the continental coast ranged from 0.2–70 days, with 84% of animals making this transit within 4 days - a conservative estimate for HPAI infectious period. Our findings demonstrate BBA, SAFS and MAG connectivity between the Falkland Islands and mainland South America over an expansive spatial network and numerous pathways, which has implications for infectious disease persistence, transmission and spread. This information is vital in supporting HPAI disease surveillance, risk assessment and marine management efforts across the region.
- Framework for mapping key areas for marine megafauna to inform Marine Spatial Planning: The Falkland Islands case studyPublication . Augé, Amélie A.; Dias, Maria P.; Lascelles, Ben; Baylis, Alastair M.M.; Black, Andy; Boersma, P. Dee; Catry, Paulo; Crofts, Sarah; Galimberti, Filippo; Granadeiro, José Pedro; Hedd, April; Ludynia, Katrin; Masello, Juan F.; Montevecchi, William A.; Phillips, Richard A.; Pütz, Klemens; Quillfeldt, Petra; Rebstock, Ginger A.; Sanvito, Simona; Staniland, Iain J.; Stanworth, Andrew J.; Thompson, Dave R.; Tierney, Megan; Trathan, Philip N.; Croxall, John P.Marine Spatial Planning (MSP) is becoming a key management approach throughout the world. The process includes the mapping of how humans and wildlife use the marine environment to inform the development of management measures. An integrated multi-species approach to identifying key areas is important for MSP because it allows managers a global representation of an area, enabling them to see where management can have the most impact for biodiversity protection. However, multi-species analysis remains challenging. This paper presents a methodological framework for mapping key areas for marine megafauna (seabirds, pinnipeds, cetaceans) by incorporating different data types across multiple species. The framework includes analyses of tracking data and observation survey data, applying analytical steps according to the type of data available during each year quarter for each species. It produces core-use area layers at the species level, then combines these layers to create megafauna core-use area layers. The framework was applied in the Falkland Islands. The study gathered over 750,000 tracking and at-sea observation locations covering an equivalent of 5495 data days between 1998 and 2015 for 36 species. The framework provides a step-by-step implementation protocol, replicable across geographic scales and transferable to multiple taxa. R scripts are provided. Common repositories, such as the Birdlife International Tracking Database, are invaluable tools, providing a secure platform for storing and accessing spatial data to apply the methodological framework. This provides managers with data necessary to enhance MSP efforts and marine conservation worldwide.
- Important At-Sea areas of colonial breeding marine predators on the Southern Patagonian ShelfPublication . Baylis, Matthew; Tierney, Megan; Orben, Rachael; Evans, Victoria Warwick; Wakefield, Ewan; Grecian, William James; Trathan, Phil; Reisinger, Ryan R.; Ratcliffe, Norman Arthur; Croxall, John; Campioni, Letizia; Catry, Paulo; Crofts, Sarah; Boersma, P. Dee; Galimberti, Filippo; Granadeiro, José Pédro; Handley, Jonathan; Hayes, Sean; Hedd, April; Masello, Juan; Montevecchi, William A.; Pütz, Klemens; Quillfeldt, Petra; Rebstock, Ginger A.; Sanvito, Simona; Staniland, Iain; Brickle, PaulThe Patagonian Shelf Large Marine Ecosystem supports high levels of biodiversity and endemism and is one of the most productive marine ecosystems in the world. Despite the important role marine predators play in structuring the ecosystems, areas of high diversity where multiple predators congregate remains poorly known on the Patagonian Shelf. Here, we used biotelemetry and biologging tags to track the movements of six seabird species and three pinniped species breeding at the Falkland Islands. Using Generalized Additive Models, we then modelled these animals' use of space as functions of dynamic and static environmental indices that described their habitat. Based on these models, we mapped the predicted distribution of animals from both sampled and unsampled colonies and thereby identified areas where multiple species were likely to overlap at sea. Maximum foraging trip distance ranged from 79 to 1,325 km. However, most of the 1,891 foraging trips by 686 animals were restricted to the Patagonian Shelf and shelf slope, which highlighted a preference for these habitats. Of the seven candidate explanatory covariates used to predict distribution, distance from the colony was retained in models for all species and negatively affected the probability of occurrence. Predicted overlap among species was highest on the Patagonian Shelf around the Falkland Islands and the Burdwood Bank. The predicted area of overlap is consistent with areas that are also important habitat for marine predators migrating from distant breeding locations. Our findings provide comprehensive multi-species predictions for some of the largest marine predator populations on the Patagonian Shelf, which will contribute to future marine spatial planning initiatives. Crucially, our findings highlight that spatially explicit conservation measures are likely to benefit multiple species, while threats are likely to impact multiple species.
- Overlap between marine predators and proposed Marine Managed Areas on the Patagonian ShelfPublication . Baylis, Alastair; Lecea, Ander M. De; Tierney, Megan; Orben, Rachael; Ratcliffe, Norman; Wakefield, Ewan; Catry, Paulo; Campioni, Letizia; Costa, Marina; Boersma, P. Dee; Galimberti, Filippo; Granadeiro, José P.; Masello, Juan; Puetz, Klemens; Quillfeldt, Petra; Rebstock, Ria; Sanvito, Simona; Staniland, Iain; Brickle, PaulAbstract. Static (fixed-boundary) protected areas are key ocean conservation strategies, and marine higher predator distribution data can play a leading role toward identifying areas for conservation action. The Falkland Islands are a globally significant site for colonial breeding marine higher predators (i.e., seabirds and pinnipeds). However, overlap between marine predators and Falkland Islands proposed Marine Managed Areas (MMAs) has not been quantified. Hence, to provide information required to make informed decisions regarding the implementation of proposed MMAs, our aims were to objectively assess how the proposed MMA network overlaps with contemporary estimates of marine predator distribution. We collated tracking data (1999–2019) and used a combination of kernel density estimation and model-based predictions of spatial usage to quantify overlap between colonial breeding marine predators and proposed Falkland Islands MMAs. We also identified potential IUCN Key Biodiversity Areas (pKBAs) using (1) kernel density based methods originally designed to identify Important Bird and Biodiversity Areas (IBAs) and (2) habitat preference models. The proposed inshore MMA, which extends three nautical miles from the Falkland Islands, overlapped extensively with areas used by colonial breeding marine predators. This reflects breeding colonies being distributed throughout the Falklands archipelago, and use being high adjacent to colonies due to central-place foraging constraints. Up to 45% of pKBAs identified via kernel density estimation were located within the proposed MMAs. In particular, the proposed Jason Islands Group MMA overlapped with pKBAs for three marine predator species, suggesting it is a KBA hot spot. However, tracking data coverage was incomplete, which biased pKBAs identified using kernel density methods, to colonies tracked. Moreover, delineation of pKBA boundaries were sensitive to the choice of smoothing parameter used in kernel density estimation. Delineation based on habitat model predictions for both sampled and unsampled colonies provided less biased estimates, and revealed 72% of the Falkland Islands Conservation Zone was likely a KBA. However, it may not be practical to consider such a large area for fixed-boundary management. In the context of wide-ranging marine predators, emerging approaches such as dynamic ocean management could complement static management frameworks such as MMAs, and provide protection at relevant spatiotemporal scales.