Biology subjects

Richardson, A. J.

Publications and source records attributed to Richardson, A. J..

7 recordsLinked to original sources

bioRxiv2026

Area use and residency behaviour at reproductive and foraging areas of green turtles from the largest rookery in the Atlantic

The conservation of migratory marine megavertebrates depends on the protection of different areas during their life cycles. Many populations have recovered following exploitation-driven declines. Green turtles exemplify successful efforts protecting reproductive populations, reducing harvesting, promoting population recoveries globally. Tortuguero, Costa Rica, the second largest rookeries for green turtles worldwide, implemented long-term conservation efforts leading to a population recovery, which is now in decline. This study investigates migratory connectivity of green turtles from Tortuguero across the Caribbean, and the role marine protected areas (MPAs) play in protecting key habitats supporting this population. Over 25 years, we satellite tagged 63 female green turtles to study their internesting and post-nesting foraging movements. Applying a state-space model, we calculated a movement-persistence index, to separate internesting and foraging periods. We calculated turtles' utilization distribution areas for both periods. To assess the protection coverage at each end of the migration, we calculated time spent within and outside MPAs. Tracked turtles spent a median of 42.3 days (SD=18.8, range=12-80) within 30 km offshore before departing the internesting area, spending just 23.0% of time within nearby MPAs. After nesting, turtles migrated to 14 different foraging areas, Miskitos Cays, Nicaragua hosted the most turtles (n=23). Mean transmission time in foraging areas was 175.6 days (SD=126.0; range=13-544). Generally, turtles foraged 58.0% of the time within MPAs boundaries; however, ~32% of tracked turtles foraged outside MPAs. Considering all known stressors, we found this population to be insufficiently protected at either end of their migratory cycle, remaining vulnerable to regional threats.

ecology↗

bioRxiv2025

Biodiversity databases as underutilized resources for pathogen discovery: a quantitative synthesis of bat and rodent tissue collections in natural history museums

Zoonotic spillovers are becoming increasingly frequent, and the devastating effects of the SARS-CoV-2 pandemic demonstrate our continued inability to combat their consequences effectively. Natural history museums can enhance the study of zoonoses by serving as valuable resources for understanding the ecology and evolutionary history of pathogens and their wildlife hosts. Despite the growing interest in the role museums can play in pathobiology research and zoonotic risk assessment, there remains a lack of centralized resources for locating tissue samples that may be leveraged for pathogen discovery. Using the worlds most significant global aggregator of museum specimens, The Global Biodiversity Information Facility (GBIF), we examined how such tools could be adopted to identify specimens that might be sources of viral genetic material. Focusing on tissue samples from the mammalian orders Rodentia and Chiroptera, speciose taxa that host a high diversity of known zoonotic viruses, we examined temporal, spatial, and taxonomic gaps and patterns in the available tissue samples. Our analyses reveal a heavy bias toward tissue samples collected from the Americas (and consequently, taxonomic groups found in the Americas), with most collected samples housed in North American institutions. This limits the scope of future pathogen discovery efforts and presents a barrier to pandemic preparedness in the Global South. We also examine gaps in metadata quality (e.g., descriptions of preservation method and storage medium) and outline recommendations for GBIF to facilitate future biosurveillance projects and effectively incorporate natural history museums into One Health disease research. Author SummaryThe SARS-CoV-2 pandemic has driven a greater research focus on understanding wildlife reservoirs of zoonotic pathogens. As a complement to field-based sampling of wildlife, natural history museum collections house millions of specimens that could be used by researchers to study pathogens quickly, safely, and cost-effectively. Digital databases of museum specimens and their associated tissue samples were originally created for biodiversity research, but these could be adapted to guide pathogen discovery research. Using the largest of these databases, The Global Biodiversity Information Facility, we explored tissue samples from rodents and bats, which have been shown to carry a disproportionate number of zoonotic pathogens. We searched for keywords that would indicate the presence of relevant tissue samples and then mapped the results visually. This revealed disproportionate distributions of tissue samples across time, space, and taxonomy. Our study is the first attempt to assess how a biodiversity database can be used for this novel purpose. We suggest changes that would improve these databases for zoonotic disease research.

ecology↗

bioRxiv2025

Integrating migratory marine connectivity into shark conservation

Understanding migratory connectivity is important for the conservation of highly mobile marine species that face escalating threats across the globe. Establishing baseline information on migratory connectivity is therefore needed to identify regions of conservation focus. Despite efforts to track migratory sharks and rays, information on transboundary movements is limited and often inaccessible to managers and policymakers. Here, we synthesised multimethod movement data for migratory Australian shark and ray species, investigating which species require international engagement to support their population recovery. Based on data from a systematic literature review, we built connectivity networks from telemetry and mark-recapture studies that provide a first baseline for transboundary migratory connectivity for Australian sharks and rays. Of the 31 shark and ray species reviewed, we identified 6 species that link the Australian Exclusive Economic Zone to other national jurisdictions via multispecies migratory connections through the Tasman Sea to New Zealand, through the Tasman and Coral Sea to New Caledonia, and north across the Timor Sea and Torres Strait to Indonesia and Papua New Guinea. White sharks (Carcharhinus carcharias) and whale sharks (Rhincodon typus) were the most data rich, whereas 14 shark and ray species had no movement information. There is a grave deficiency in available information for endangered or critically endangered migratory shark and ray populations, with 76% having only one or no published studies. This work supports future conservation strategies for migratory sharks that require robust international collaboration and the adoption of integrated and dynamic management approaches.

ecology↗

bioRxiv2025

Ecological insights and management implications of the global migratory connectivity of green turtles

AimGreen turtles are a widely distributed and highly migratory species, despite extensive data on the movement of green turtles, there is no global synthesis on the subject, limiting a holistic understanding of their movement. Based on three decades of published literature, we present the first global model of migratory connectivity for green turtles. LocationGlobal. Time Period1990-2022. Major Taxa StudiedGreen Sea Turtle (Chelonia mydas) MethodsWe conducted a structured literature review extracting georeferenced information on the movement of green turtles from 1990 to 2022, aggregating this information into a single connectivity model, defining sites and "metasites" as nodes of connectivity. We then evaluate the connectivity routes from nesting areas to foraging sites for each RMU, identifying those trajectories moving outside and across the boundaries of these areas. ResultsWe found an increasing number of studies assessing movement of green turtles, with a total of 113 sources of migratory connectivity information. We identified 474 sites, representing locations where green turtles were observed (124 of these being nesting sites). Migratory connections from nesting sites ranged from resident turtles never leaving the area, to rookeries linked to 13 different sites, some over 5,000 km apart. This long-distance connectivity exposes populations to threats across disparate locations. Most connections traversed national jurisdictions, including crossing different Regional Management Units Main ConclusionsWe compiled the largest available dataset describing movement of green turtles worldwide and present the first global model of their migratory connectivity. This model provides ecological insights into regional differences in life histories, identifies geographic and demographic gaps in sampling, and provides baseline information on connectivity to support transboundary management of green turtle populations. The study highlights the need for larger collaborative efforts to aggregate knowledge beyond local jurisdictions, to inform and align effective management measures to protect this threatened species.

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bioRxiv2025

Valuing conservation and natural wealth: The blue economy of manta ray watching in the Maldives

Amid declining manta ray populations globally, the well-established and growing manta ray tourism industries generate substantial economic benefits and aid protective legislation for these threatened elasmobranchs. As flagship species, manta rays are a drawcard for marine wildlife tourism and a gateway for engaging the public and communities in conservation. Healthy marine ecosystems are the key drivers of employment and economic sustainability for island nations such as the Maldives. However, there are many stakeholders competing for these shared resources, which can result in environmental degradation. Economic evaluations are a powerful tool for justifying the conservation efforts of threatened species and natural areas, especially in light of competing stakeholders. Using tour operator surveys (n=106) and data mining, this study provides an updated assessment of manta ray watching tourism in the Maldives, and represents the first national evaluation of its total economic and socio-economic benefits. In 2021, manta ray tourism in the Maldives generated an estimated US$227.3 million, including US$39 million on manta ray focused diving and snorkelling excursions, and US$188.3 million in related tourist expenditure. This represented 4.8% of the national Gross Domestic Product. This industry appears to have grown around 380% since 2008 (US$8.1 million) and manta ray watching is now offered by 80% of tourism operators nation-wide. Our findings revealed that manta rays hold intrinsic value and cultural significance within local communities. Acknowledging this, the flow-on benefits to the community extend beyond this industry, reaching local businesses, employed staff, and the government with the total economic benefits of the manta ray tourism industry were estimated at over US$311 million per year. Such value highlights the significance of manta rays for this nation and the need for effective management centred on manta ray conservation to safeguard future prosperity and mitigate the potential impact of tourism on manta ray populations.

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bioRxiv2020

Incorporating climate velocity into the design of climate-smart networks of protected areas

Climate change is redistributing terrestrial and marine biodiversity and altering fundamental ecological interactions. To adequately conserve biodiversity and promote its long-term persistence, protected areas should account for the ecological implications of species redistribution. Data paucity across many systems means that achieving this goal requires generic metrics that represent likely responses of multiple taxa to climate change. Climate velocity is one such metric, reflecting potential species range shifts at a generic level. Here, we explore four approaches to incorporating climate velocity metrics into the design of protected areas using the Mediterranean Sea as an illustrative example. Our methods are designed to meet two climate-smart planning objectives: 1) protect climate refugia by selecting slow-moving climate velocity areas, and 2) maintain the capacity of ecological systems to adapt by representing a suite of climate-velocity trajectory classes. We found that incorporating climate velocity as a cost measure in Marxan is the best approach for selecting slower-moving areas, which are good indicators of climate refugia. However, this approach fails to accommodate socio-economic cost data, and is probably impractical. Incorporating climate velocity as a boundary or as a feature provides both selection of slower-moving areas and solutions with lower socio-economic cost. Finally, we were able to design cost-effective networks of protected areas representing a suite of climate-velocity trajectories classes, which have the potential to help species adapt to a changing climate. This work presents simple and practical ways of including climate velocity in conservation plans on land and in the ocean to achieve the key climate-smart objectives of protecting climate refugia and enhancing ecological resilience.

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bioRxiv2019

The geographic distribution of reef and oceanic manta rays in the south-east Indian and south-west Pacific Oceans

The reef manta ray, Mobula alfredi, occurs in tropical and warm temperate coastal waters, and around islands and reefs in the Pacific and Indian Oceans. Published records that relate to the distribution of M. alfredi in the south-east Indian and south-west Pacific Oceans are largely restricted to locations where there is a focus on manta ray ecotourism, with little information from elsewhere. Even less is known about the circumglobally distributed oceanic manta ray, Mobula birostris, for which there are few published sighting records. We collated n = 11,703 sighting records from Australian waters and offshore territories for M. alfredi sourced from scientific image databases (n = 10,715), aerial surveys (n = 375) and online reports (n = 613). From collated records, we confirm that the species shows an uninterrupted distribution within Australian coastal waters north of 26{degrees}S on the west coast to 31{degrees}S on the east coast, with a southernmost record at 34{degrees}S. Confirmed locations for M. birostris encompass a latitudinal range of 10-40{degrees}S. Records from more southerly locations relate to warm-water events. Sightings of M. birostris were rare, but were confirmed at several geographically separate locations, probably reflecting its preference for offshore waters. The study clarifies the occurrence and range of each species within coastal waters of the south-east Indian and south-west Pacific Oceans, and highlights regions in northern Australia that are of specific interest for future research into possible movements of individuals between international marine jurisdictions.

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