Megafaunal Species Research Articles

Underwater Visual Records of Marine Megafauna Around Offshore Anthropogenic Structures

In oceans and seas worldwide, an increasing number of end-of-life anthropogenic offshore structures (e.g. platforms, pipelines, manifolds, windfarms, etc.) are facing full or partial removal. As part of the decommissioning process, studies on potential importance of subsea infrastructure to marine megafauna (defined as: cetaceans, pinnipeds, sirenians, large fish – such as sharks, rays, billfishes, and tuna, as well as marine reptiles, and seabirds) are lacking. Dedicated scientific Remotely Operated Vehicle (ROV) surveys around offshore installations are rare, but there is a wealth of archived industrial data and noteworthy species sightings posted publicly on various social media platforms. This study used routine, incidentally-collected ROV (n = 73) and commercial diver (n = 9) video recordings spanning 1998–2019 globally. Data were gathered directly from industrial partners (n = 36) and the public domain (YouTube; n = 46) to provide an account of marine megafauna presence and potential feeding behaviour in the near visible vicinity of subsea anthropogenic structures. A total of 79 video clips and 3 still images of marine megafauna near offshore structures were examined, resulting in 67 individual sightings and 16 sub-sightings (in which an individual was recorded within the same day). At least 178 individuals were identified to a minimum of 17 species of marine megafauna, amounting to a total (combined) sighting duration of 01:09:35 (hh:mm:ss). Results demonstrated proximate presence of marine megafauna (many of which are threatened species) to anthropogenic structures, with most animals displaying foraging or interaction behaviours with the structures. Observations included the deepest (2,779 m) confirmed record of a sleeper shark (Somniosus spp.) and the first confirmed visual evidence of seals following pipelines. These ROV observations demonstrate a latent source of easily-accessible information that can expand understanding of marine megafauna interactions with offshore anthropogenic infrastructure. Consequently, other workers in this field should be encouraged to re-analyse archived datasets, commence further collaborative research projects with industrial partners, and/or expand Internet search terms to additional species assemblages, in a bid to quantitatively elucidate relationships between offshore infrastructure and marine species.

Climatic and Resource Determinants of Forest Elephant Movements

As a keystone megafaunal species, African forest elephants (Loxodonta cyclotis) influence the structure and composition of tropical forests. Determining the links between food resources, environmental conditions and elephant movement behavior is crucial to understanding their habitat requirements and their effects on the ecosystem, particularly in the face of poaching and global change. We investigate whether fruit abundance or climate most strongly influence forest elephant movement behavior at the landscape scale in Gabon. Trained teams of ‘elephant trackers’ performed daily fruit availability and dietary composition surveys over a year within two relatively pristine and intact protected areas. With data from 100 in-depth field follows of 28 satellite-collared elephants and remotely sensed environmental layers, we use linear mixed-effects models to assess the effects of sites, seasons, individual identification, elephant diet, and fruit availability on elephant movement behavior at monthly and three-day time scales. At the month-level, rainfall, and to a lesser extent fruit availability, most strongly predicted the proportion of time elephants spent in long, directionally persistent movements. Thus, even elephants in moist tropical rainforests show seasonal behavioral phenotypes linked to rainfall. At the follow-level (2-4 day intervals), relative support for both rainfall and fruit availability decreased markedly, suggesting that at finer spatial scales forest elephants make foraging decisions largely based on other factors not directly assessed here. Individual identity explained the majority of the variance in the data, and there was strong support for interindividual variation in behavioral responses to rainfall. Taken together, this highlights the importance of approaches which follow individuals through space and time. The links between climate, resource availability and movement behavior provide important insights into the behavioral ecology of forest elephants that can contribute to understanding their role as seed dispersers, improving management of populations, and informing development of solutions to human-elephant conflict.

Rhino Horn: Are There Viable Alternatives?

The number of rhinos being poached on private and national game reserves in Africa annually is unsustainable. The demand for rhino horn is having a detrimental effect on rhino populations with extirpations occurring throughout Africa. Traditional Chinese medicine and commercial art material are at the forefront of the problem with large syndicates poaching rhino and selling this product on the illegal black market in Asia, with high sales being documented in Vietnam. Alternative methods need to be considered and implemented to prevent extinction of an iconic megafauna species which has the potential to alter the biodiversity system in the Savannah regions if this species disappears in situ. Dehorning, legalising the trade (both nationally and internationally) and education are key areas which need to be addressed. However, it is vital to note that these alternatives only have the potential to be successful if implemented together and with the support from the traders, the consumers, but also from the government. It is imperative that all governments enforce current legislation on the trade and provide monetary and conservation backing to those individuals protecting their current rhino populations.

Vertical distribution of megafauna on the Bering Sea slope based on ROV survey.

Video surveys were carried out during the 75th cruise of the RV Akademik M.A. Lavrentyev (June 2016) along the northern slope of the Volcanologists Massif, in the south-western Bering Sea. The seafloor was explored using the ROV Comanche 18. Seven dives were performed in the depth range from 4,278 m to 349 m. Overall, about 180 species of megafauna were recognised. Fifteen types of megafauna communities corresponding to certain depth ranges were distinguished based on the most abundant taxa. Dominance changed with depth in the following order: the holothurian Kolga kamchatica at the maximum depth (4,277–4,278 m); the holothurian Scotoplanes kurilensis at 3,610–2,790 m; the ophiuroid Ophiura bathybia at 3,030–2,910 m; benthic shrimps of the family Crangonidae at 2,910–2,290 m; the holothurian Paelopatides solea at 2,650–2,290 m; benthic jellyfish from the family Rhopalonematidae at 2,470–2,130 m; the enteropneust Torquaratoridae at 2,290–1,830 m; the holothurian Synallactes chuni and the ophiuroid of the genera Ophiura and Ophiocantha at 1,830–1,750 m. At depths 1,750–720 m most of the megafauna was associated with live or dead colonies of the sponge Farrea spp. Depths 720–390 m were dominated by the coral Heteropolypus ritteri and/or Corallimorphus pilatus. At 390–350 m depth, the shallowest depth range, the dominant taxon was the zoantharian Epizoanthus sp. Soft sediment megafauna communities dominated by torquaratorid enteropneusts to our knowledge have not been observed before in the deep-sea, the same as communities with a dominance of benthopelagic rhopalonematid jellyfish. The depths of the largest community changes, or the largest turnover of dominant species, were revealed at ∼2,790 m between the bathyal and abyssal zones and ∼1,750 m and ∼720 m within the bathyal zone.

Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems

BackgroundA strong behavioural plasticity is commonly evidenced in the movements of marine megafauna species, and it might be related to an adaptation to local conditions of the habitat. One way to investigate such behavioural plasticity is to satellite track a large number of individuals from contrasting foraging grounds, but despite recent advances in satellite telemetry techniques, such studies are still very limited in sea turtles.MethodsFrom 2010 to 2018, 49 juvenile green turtles were satellite tracked from five contrasting feeding grounds located in the South-West Indian Ocean in order to (1) assess the diel patterns in their movements, (2) investigate the inter-individual and inter-site variability, and (3) explore the drivers of their daily movements using both static (habitat type and bathymetry) and dynamic variables (daily and tidal cycles).ResultsDespite similarities observed in four feeding grounds (a diel pattern with a decreased distance to shore and smaller home ranges at night), contrasted habitats (e.g. mangrove, reef flat, fore-reef, terrace) associated with different resources (coral, seagrass, algae) were used in each island.ConclusionsJuvenile green turtles in the South-West Indian Ocean show different responses to contrasting environmental conditions - both natural (habitat type and tidal cycle) and anthropogenic (urbanised vs. uninhabited island) demonstrating the ability to adapt to modification of habitat.

From sea monsters to charismatic megafauna: Changes in perception and use of large marine animals.

Marine megafauna has always elicited contrasting feelings. In the past, large marine animals were often depicted as fantastic mythological creatures and dangerous monsters, while also arousing human curiosity. Marine megafauna has been a valuable resource to exploit, leading to the collapse of populations and local extinctions. In addition, some species have been perceived as competitors of fishers for marine resources and were often actively culled. Since the 1970s, there has been a change in the perception and use of megafauna. The growth of marine tourism, increasingly oriented towards the observation of wildlife, has driven a shift from extractive to non-extractive use, supporting the conservation of at least some species of marine megafauna. In this paper, we review and compare the changes in the perception and use of three megafaunal groups, cetaceans, elasmobranchs and groupers, with a special focus on European cultures. We highlight the main drivers and the timing of these changes, compare different taxonomic groups and species, and highlight the implications for management and conservation. One of the main drivers of the shift in perception, shared by all the three groups of megafauna, has been a general increase in curiosity towards wildlife, stimulated inter alia by documentaries (from the early 1970s onwards), and also promoted by easy access to scuba diving. At the same time, environmental campaigns have been developed to raise public awareness regarding marine wildlife, especially cetaceans, a process greatly facilitated by the rise of Internet and the World Wide Web. Currently, all the three groups (cetaceans, elasmobranchs and groupers) may represent valuable resources for ecotourism. Strikingly, the economic value of live specimens may exceed their value for human consumption. A further change in perception involving all the three groups is related to a growing understanding and appreciation of their key ecological role. The shift from extractive to non-extractive use has the potential for promoting species conservation and local economic growth. However, the change in use may not benefit the original stakeholders (e.g. fishers or whalers) and there may therefore be a case for providing compensation for disadvantaged stakeholders. Moreover, it is increasingly clear that even non-extractive use may have a negative impact on marine megafauna, therefore regulations are needed.

Long-term effects of cultural filtering on megafauna species distributions across China

Human activities currently play a dominant role in shaping and eroding Earth's biodiversity, but the historical dynamics leading to this situation are poorly understood and contentious. Importantly, these dynamics are often studied and discussed without an emphasis on cultural evolution, despite its potential importance for past and present biodiversity dynamics. Here, we investigate whether cultural filtering, defined as the impact of cultural evolution on species presence, has driven the range dynamics of five historically widespread megafauna taxa (Asiatic elephant, rhinoceroses, tiger, Asiatic black bear, and brown bear) across China over the past 2 millennia. Data on megafauna and sociocultural history were compiled from Chinese administrative records. While faunal dynamics in China are often linked to climate change at these time scales, our results reveal cultural filtering as the dominant driver of range contractions in all five taxa. This finding suggests that the millennia-long spread of agricultural land and agricultural intensification, often accompanied by expansion of the Han culture, has been responsible for the extirpation of these megafauna species from much of China. Our results suggest that cultural filtering is important for understanding society's role in the assembly of contemporary communities from historical regional species pools. Our study provides direct evidence that cultural evolution since ancient times has overshadowed climate change in shaping broadscale megafauna biodiversity patterns, reflecting the strong and increasing importance of sociocultural processes in the biosphere.

Potential ecological and socio-economic effects of a novel megaherbivore introduction: the hippopotamus in Colombia

AbstractIntroduced species can have strong ecological, social and economic effects on their non-native environment. Introductions of megafaunal species are rare and may contribute to rewilding efforts, but they may also have pronounced socio-ecological effects because of their scale of influence. A recent introduction of the hippopotamusHippopotamus amphibiusinto Colombia is a novel introduction of a megaherbivore onto a new continent, and raises questions about the future dynamics of the socio-ecological system into which it has been introduced. Here we synthesize current knowledge about the Colombian hippopotamus population, review the literature on the species to predict potential ecological and socio-economic effects of this introduction, and make recommendations for future study. Hippopotamuses can have high population growth rates (7–11%) and, on the current trajectory, we predict there could be 400–800 individuals in Colombia by 2050. The hippopotamus is an ecosystem engineer that can have profound effects on terrestrial and aquatic environments and could therefore affect the native biodiversity of the Magdalena River basin. Hippopotamuses are also aggressive and may pose a threat to the many inhabitants of the region who rely upon the Magdalena River for their livelihoods, although the species could provide economic benefits through tourism. Further research is needed to quantify the current and future size and distribution of this hippopotamus population and to predict the likely ecological, social and economic effects. This knowledge must be balanced with consideration of social and cultural concerns to develop appropriate management strategies for this novel introduction.

Future large hydropower dams impact global freshwater megafauna

Dam construction comes with severe social, economic and ecological impacts. From an ecological point of view, habitat types are altered and biodiversity is lost. Thus, to identify areas that deserve major attention for conservation, existing and planned locations for (hydropower) dams were overlapped, at global extent, with the contemporary distribution of freshwater megafauna species with consideration of their respective threat status. Hydropower development will disproportionately impact areas of high freshwater megafauna richness in South America, South and East Asia, and the Balkan region. Sub-catchments with a high share of threatened species are considered to be most vulnerable; these are located in Central America, Southeast Asia and in the regions of the Black and Caspian Sea. Based on this approach, planned dam locations are classified according to their potential impact on freshwater megafauna species at different spatial scales, attention to potential conflicts between climate mitigation and biodiversity conservation are highlighted, and priorities for freshwater management are recommended.

Using Cumulative Impact Mapping to Prioritize Marine Conservation Efforts in Equatorial Guinea

Marine biodiversity is under extreme pressure from anthropogenic activity globally, leading to calls to protect at least 10% of the world’s oceans within marine protected areas (MPAs) and other effective area-based conservation measures by 2020. Fulfilling such commitments, however, requires a detailed understanding of the distribution of potentially detrimental human activities, and their predicted impacts. One such approach that is being increasingly used to strengthen our understanding of human impacts is cumulative impact mapping; as it can help identify economic sectors with the greatest potential impact on species and ecosystems in order to prioritise conservation management strategies, providing clear direction for intervention. In this paper, we present the first local cumulative utilisation impact mapping exercise for the Bioko-Corisco-Continental area of Equatorial Guinea’s Exclusive Economic Zone – situated in the Gulf of Guinea one of the most important and least studied marine regions in the Eastern Central Atlantic. This study examines the potential impact of ten direct anthropogenic activities on a suite of key marine megafauna species and reveals that the most suitable habitats for these species, located on the continental shelf, are subject to the highest threat scores. However, in some coastal areas, the persistence of highly suitable habitat subject to lower threat scores suggests that there are still several strategic areas that are less impacted by human activity that may be suitable sites for protected area expansion. Highlighting both the areas with potentially the highest impact, and those with lower impact levels, as well as particularly damaging activities can inform the direction of future conservation initiatives in the region.

Who’s better at spotting? A comparison between aerial photography and observer-based methods to monitor floating marine litter and marine mega-fauna

Pollution by marine litter is raising major concerns due to its potential impact on marine biodiversity and, above all, on endangered mega-fauna species, such as cetaceans and sea turtles. The density and distribution of marine litter and mega-fauna have been traditionally monitored through observer-based methods, yet the advent of new technologies has introduced aerial photography as an alternative monitoring method. However, to integrate results produced by different monitoring techniques and consider the photographic method a viable alternative, this ‘new’ methodology must be validated. This study aims to compare observations obtained from the concurrent application of observer-based and photographic methods during aerial surveys. To do so, a Partenavia P-68 aircraft equipped with an RGB sensor was used to monitor the waters off the Spanish Mediterranean coast along 12 transects (941 km). Over 10000 images were collected and checked manually by a photo-interpreter to detect potential targets, which were classified as floating marine macro-litter, mega-fauna and seabirds. The two methods allowed the detection of items from the three categories and proved equally effective for the detection of cetaceans, sea turtles and large fish on the sea surface. However, the photographic method was more effective for floating litter detection and the observer-based method was more effective for seabird detection. These results provide the first validation of the use of aerial photography to monitor floating litter and mega-fauna over the marine surface.

Ecological Role of an Offshore Industry Artificial Structure

Decommissioning of oil and gas infrastructure in all major basins globally has focused attention on its importance as hard substratum on continental shelf and slope habitats. Observational studies are needed to improve understanding of faunal assemblages supported by offshore infrastructure and better predict the effect of removal. Here we present results from visual inspection and physical sampling of a small oil and gas industry structure decommissioned from an oil field in the North East Atlantic. This is supported by observations of similar structures nearby and by photographs of the surrounding seabed from environmental baseline surveys. The structure supported a reasonably high biomass and diversity of invertebrates (>10 kg and > 39 macrofaunal and 17 megafaunal species) and fishes (>20 kg biomass and > 4 species). The invertebrate megafaunal species present on the structure were a sub-set of the hard substratum fauna observed on surrounding seabed. Porifera were absent from the structure. Biological succession in the first two years occurred as follows. Sparse colonies of the hydroid Obelia sp. stet were early colonisers then subsequent development of thick hydroid turf (Obelia sp. stet. and Halecium sp. stet.) supported a diverse invertebrate assemblage (2654 individuals kg wet mass-1) dominated by saddle oysters (Pododesmus squama (Gmelin, 1791) and Heteranomia sp. stet.)) and scale worms (Hormothoe spp.). Percentage cover of hydroid turf varied significantly over the structure, with most growth on sections exposed to strongest currents. Commercially important fish species present around the structure included Gadus morhua (Atlantic cod), Pollachius virens (saithe) and Lophius piscatorius (monkfish). Studies of artificial structures such as this provide much needed data to understand their role in the ecology of seafloor habitats and inform environmental decision making on all stages of industry from exploration to decommissioning. We show that the ecological role of the decommissioned three-dimensional structures was to enhance the biomass of a sub-set of epifaunal invertebrates found in the area. This supported diverse associated macrofaunal organisms, providing a food source for motile invertebrates and fishes in an area where background hard substratum can be lost through the impacts of drilling.

Anthropocene refugia: integrating history and predictive modelling to assess the space available for biodiversity in a human-dominated world.

During periods of strong environmental change, some areas may serve as refugia, where components of biodiversity can find protection, persist and potentially expand from should conditions again become favourable. The refugia concept has previously been used in the context of climatic change, to describe climatically stable areas in which taxa survived past Quaternary glacial-interglacial oscillations, or where they might persist in the future under anthropogenic climate change. However, with the recognition that Earth has entered the Anthropocene, an era in which human activities are the dominant driving force on ecosystems, it is critical to also consider human pressures on the environment as factors limiting species distributions. Here, we present a novel concept, Anthropocene refugia, to refer to areas that provide spatial and temporal protection from human activities and that will remain suitable for a given taxonomic unit in the long-term. It integrates a deep-time perspective on species biogeography that provides information on the natural rather than current-day relictual distribution of species, with spatial information on modern and future anthropogenic threats. We define the concept and propose a methodology to effectively identify and map realized and potential current and future refugia, using examples for two megafaunal species as a proof of concept. We argue that identifying Anthropocene refugia will improve biodiversity conservation and restoration by allowing better prediction of key areas for conservation and potential for re-expansions today and in the future. More generally, it forms a new conceptual framework to assess and manage the impact of anthropogenic activities on past, current and future patterns of species distributions. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'

Fauna of the Kemp Caldera and its upper bathyal hydrothermal vents (South Sandwich Arc, Antarctica).

Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known than those at vents on mid-ocean ridges and back-arc spreading centres. This study characterizes chemosynthetic biotopes at active hydrothermal vents discovered at the Kemp Caldera in the South Sandwich Arc. The caldera hosts sulfur and anhydrite vent chimneys in 1375–1487 m depth, which emit sulfide-rich fluids with temperatures up to 212°C, and the microbial community of water samples in the buoyant plume rising from the vents was dominated by sulfur-oxidizing Gammaproteobacteria. A total of 12 macro- and megafaunal taxa depending on hydrothermal activity were collected in these biotopes, of which seven species were known from the East Scotia Ridge (ESR) vents and three species from vents outside the Southern Ocean. Faunal assemblages were dominated by large vesicomyid clams, actinostolid anemones, Sericosura sea spiders and lepetodrilid and cocculinid limpets, but several taxa abundant at nearby ESR hydrothermal vents were rare such as the stalked barnacle Neolepas scotiaensis. Multivariate analysis of fauna at Kemp Caldera and vents in neighbouring areas indicated that the Kemp Caldera is most similar to vent fields in the previously established Southern Ocean vent biogeographic province, showing that the species composition at island-arc hydrothermal vents can be distinct from nearby seafloor-spreading systems. δ13C and δ15N isotope values of megafaunal species analysed from the Kemp Caldera were similar to those of the same or related species at other vent fields, but none of the fauna sampled at Kemp Caldera had δ13C values, indicating nutritional dependence on Epsilonproteobacteria, unlike fauna at other island-arc hydrothermal vents.

Artisanal longline fishing the Galapagos Islands –effects on vulnerable megafauna in a UNESCO World Heritage site

Marine megafauna (elasmobranchs, marine mammals, turtles, and seabirds) are important ecologically and economically because many species often occupy upper trophic levels as adults and are essential for marine-based tourism in many areas of the world. This group of species is also heavily impacted by fishing because most have late sexual maturity, longevity, and low reproductive output, which affects their ability to recover from depletion. In Galapagos, marine megafauna species are protected from fishing throughout the marine reserve and are the main attraction for marine-based tourism, helping generate millions of dollars in revenue annually. Despite their importance in the archipelago, these species are being caught as bycatch in the multiple artisanal longlining projects that have been carried out since the implementation of the reserve in 1998. Longlining was originally proposed as a way of redirecting fishing effort from the severely depleted coastal-demersal species to pelagic fish such as yellowfin tuna and swordfish. Although all these projects have resulted in high bycatch of megafauna, longline fishing projects have continued without independent scientific studies to evaluate their impact, largely due to poor objective definition, data collection, and enforcement. To fill in this knowledge gap, we analyzed data of the fifth experimental longline fishing project undertaken in 2012–2013 to describe the fishery, identify variables affecting the composition and quantity of bycatch, and suggest mitigation strategies. This experimental project had twelve vessels, which deployed 42,007 hooks catching 4893 individuals of 33 species, mostly yellowfin tuna and swordfish. Of those, 16 species were protected megafauna, particularly blacktip sharks (Carcharhinus limbatus) and oceanic manta (Mobula birostris). These species were regularly captured during the two seasons and in the three bioregions that occur in the archipelago, suggesting little potential to mitigate their catch. As an alternative, we identified 14 hotspots where yellowfin tuna and swordfish could be harvested in large numbers sustainably through more selective fishing techniques such as pole fishing, a method that is also more economical for artisanal fishers. In an archipelago where the main economic activity is marine wildlife tourism, the implementation of an extractive and unselective activity such as pelagic longing fishing should be avoided to ensure the sustainability of the Galapagos marine ecosystem and its booming tourism industry.

Micro Methods for Megafauna: Novel Approaches to Late Quaternary Extinctions and Their Contributions to Faunal Conservation in the Anthropocene.

Drivers of Late Quaternary megafaunal extinctions are relevant to modern conservation policy in a world of growing human population density, climate change, and faunal decline. Traditional debates tend toward global solutions, blaming either dramatic climate change or dispersals of Homo sapiens to new regions. Inherent limitations to archaeological and paleontological data sets often require reliance on scant, poorly resolved lines of evidence. However, recent developments in scientific technologies allow for more local, context-specific approaches. In the present article, we highlight how developments in five such methodologies (radiocarbon approaches, stable isotope analysis, ancient DNA, ancient proteomics, microscopy) have helped drive detailed analysis of specific megafaunal species, their particular ecological settings, and responses to new competitors or predators, climate change, and other external phenomena. The detailed case studies of faunal community composition, extinction chronologies, and demographic trends enabled by these methods examine megafaunal extinctions at scales appropriate for practical understanding of threats against particular species in their habitats today.

Effects of best practices to reduce seabird bycatch in pelagic longline fisheries on other threatened, protected and bycaught megafauna species

Fisheries bycatch is one of main conservation problems for many threatened seabirds. Currently, it is unknown whether existing best practices to mitigate seabird bycatch in pelagic longline fisheries influence the capture of other vulnerable taxa. We assessed the effect of two seabird mitigation measures for pelagic longline fisheries on 13 threatened, protected and/or bycaught species, including elasmobranchs, teleosts, sea turtles and fur seals. Analyses were from two experimental studies in Uruguay assessing the effect of a bird scaring line (BSL) and branch lines with weights close to the hooks (weighted branch lines) on these taxa. One hundred longline sets with randomized use of a BSL were deployed. In turn, 224 paired longline sections, with control branch lines versus weighted branch lines, were deployed. BSL use did not increase the capture of any of the species addressed. No detectable differences in capture rate were recorded in our branch line weighting study. However, the effect of branch line weighting in the capture of Porbeagle shark (Lamna nasus) remains unclear and requires further research. Our study suggests that effective measures to reduce seabird bycatch in pelagic longline have no negative connotations for other vulnerable species. Caution should be exercised when interpreting our results as analyses were underpowered to detect small and subtle differences in the catch rates. We strongly encourage researchers to conduct similar studies to elucidate potential regional and across fisheries differences in the effect of seabird mitigation measures in other vulnerable taxa, as well as the effect that mitigation measures for other taxa may have on seabirds.

Predicting the local-scale spatial distribution of five megafaunal species associated with a deep-sea hydrothermal field in the Okinawa Trough, Japan

Predicting the local-scale spatial distribution of five megafaunal species associated with a deep-sea hydrothermal field in the Okinawa Trough, Japan

Large-scale mitogenomic analysis of the phylogeography of the Late Pleistocene cave bear

The cave bear (Ursus spelaeus) is one of the Late Pleistocene megafauna species that faced extinction at the end of the last ice age. Although it is represented by one of the largest fossil records in Europe and has been subject to several interdisciplinary studies including palaeogenetic research, its fate remains highly controversial. Here, we used a combination of hybridisation capture and next generation sequencing to reconstruct 59 new complete cave bear mitochondrial genomes (mtDNA) from 14 sites in Western, Central and Eastern Europe. In a Bayesian phylogenetic analysis, we compared them to 64 published cave bear mtDNA sequences to reconstruct the population dynamics and phylogeography during the Late Pleistocene. We found five major mitochondrial DNA lineages resulting in a noticeably more complex biogeography of the European lineages during the last 50,000 years than previously assumed. Furthermore, our calculated effective female population sizes suggest a drastic cave bear population decline starting around 40,000 years ago at the onset of the Aurignacian, coinciding with the spread of anatomically modern humans in Europe. Thus, our study supports a potential significant human role in the general extinction and local extirpation of the European cave bear and illuminates the fate of this megafauna species.

The global decline of freshwater megafauna.

Freshwater ecosystems are among the most diverse and dynamic ecosystems on Earth. At the same time, they are among the most threatened ecosystems but remain underrepresented in biodiversity research and conservation efforts. The rate of decline of vertebrate populations is much higher in freshwaters than in terrestrial or marine realms. Freshwater megafauna (i.e., freshwater animals that can reach a body mass ≥30kg) are intrinsically prone to extinction due to their large body size, complex habitat requirements and slow life-history strategies such as long life span and late maturity. However, population trends and distribution changes of freshwater megafauna, at continental or global scales, remain unclear. In the present study, we compiled population data of 126 freshwater megafauna species globally from the Living Planet Database and available literature, and distribution data of 44 species inhabiting Europe and the United States from literature and databases of the International Union for Conservation of Nature and NatureServe. We quantified changes in population abundance and distribution range of freshwater megafauna species. Globally, freshwater megafauna populations declined by 88% from 1970 to 2012, with the highest declines in the Indomalaya and Palearctic realms (-99% and -97%, respectively). Among taxonomic groups, mega-fishes exhibited the greatest global decline (-94%). In addition, freshwater megafauna experienced major range contractions. For example, distribution ranges of 42% of all freshwater megafauna species in Europe contracted by more than 40% of historical areas. We highlight the various sources of uncertainty in tracking changes in populations and distributions of freshwater megafauna, such as the lack of monitoring data and taxonomic and spatial biases. The detected trends emphasize the critical plight of freshwater megafauna globally and highlight the broader need for concerted, targeted and timely conservation of freshwater biodiversity.