Overlap between marine predators and proposed Marine Managed Areas on the Patagonian Shelf

Abstract

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.

Progressing delineations of key biodiversity areas for seabirds, and their application to management of coastal seas

“…The hotspots of importance we identified align with recent multi‐taxa efforts which identified important sites for upper trophic‐level predators (seals and seabirds) more generally throughout the Falkland Islands Exclusive Economic Zone (Augé et al, 2018; Baylis et al, 2021), and more specifically the near‐pristine inshore environment for whales (Baines & Weir, 2020, Key Biodiversity Areas Partnership, 2022a). However, our results differ in that they showcase an island‐wide KBA for multiple seabird species, reinforcing the global significance of these sites for the persistence of biodiversity.…”

“…A preliminary conclusion may be that these areas were omitted because the original focus of the MMAs was constrained to fisheries data used in the “Assessment of Fishing Closure Areas as Sites (AFCAS)” (FIG, 2021a), rather than a process that uses all available biodiversity data. Indeed, the current MMA proposal recognizes that it does not have biodiversity conservation as the primary objective (Baylis et al, 2021).…”

“…With this prospect of identifying more species‐specific KBA element layers, a key challenge for decision‐makers will be to determine which interventions, and at what scales, will be most appropriate for conserving biodiversity. In the case of the near‐pristine (Baylis et al, 2021; Mora‐Soto et al, 2021), and highly connected Falklands marine system (Agnew, 2002; Payne et al, 2019; Signa et al, 2021; Tabak et al, 2016), there is a unique opportunity to proactively consider the best suited actions that would be able to maintain the globally significant biodiversity in all relevant areas of Falklands waters.…”

“…In the South Atlantic Ocean, within the coastal seas of the Falkland Islands which host numerous globally important seabird populations (Augé et al, 2018; Baylis et al, 2019, 2021), there have been incomplete efforts at MSP and no Marine Protected Area (MPA) proposals. A recent project, however, culminated in proposals for Marine Management Areas (MMAs) in the Falkland Islands including one in the coastal seas.…”

“…Initiatives at the Falkland Islands which have aimed to support MSP efforts, and have focused on upper trophic‐level predators such as seabirds (Augé et al, 2018; Baylis et al, 2021), typically focused on the identification of important areas at sea via distribution data from at‐sea surveys and animal tracking, with a focus on the entire EEZ. Additionally, previous efforts both at the Falkland Islands (Forster, 2010) and beyond (Carroll et al, 2019), found that data collected by observers at‐sea showed no demonstrable link between distance from land with areas containing a high number of different species, aggregations of listed threatened species, or terrestrial locations with high seabird abundance.…”