Dietary generalism accelerates arrival and persistence of coral‐reef fishes in their novel ranges under climate change

Climate change is redistributing marine and terrestrial species globally. Life‐history traits mediate the ability of species to cope with novel environmental conditions, and can be used to gauge the potential redistribution of taxa facing the challenges of a changing climate. However, it is unclear whether the same traits are important across different stages of range shifts (arrival, population increase, persistence). To test which life‐history traits most mediate the process of range extension, we used a 16‐year dataset of 35 range‐extending coral‐reef fish species and quantified the importance of various traits on the arrival time (earliness) and degree of persistence (prevalence and patchiness) at higher latitudes. We show that traits predisposing species to shift their range more rapidly (large body size, broad latitudinal range, long dispersal duration) did not drive the early stages of redistribution. Instead, we found that as diet breadth increased, the initial arrival and establishment (prevalence and patchiness) of climate migrant species in temperate locations occurred earlier. While the initial incursion of range‐shifting species depends on traits associated with dispersal potential, subsequent establishment hinges more on a species’ ability to exploit novel food resources locally. These results highlight that generalist species that can best adapt to novel food sources might be most successful in a future ocean

A comprehensive database of quality-rated fossil ages for Sahul's Quaternary vertebrates.

The study of palaeo-chronologies using fossil data provides evidence for past ecological and evolutionary processes, and is therefore useful for predicting patterns and impacts of future environmental change. However, the robustness of inferences made from fossil ages relies heavily on both the quantity and quality of available data. We compiled Quaternary non-human vertebrate fossil ages from Sahul published up to 2013. This, the FosSahul database, includes 9,302 fossil records from 363 deposits, for a total of 478 species within 215 genera, of which 27 are from extinct and extant megafaunal species (2,559 records). We also provide a rating of reliability of individual absolute age based on the dating protocols and association between the dated materials and the fossil remains. Our proposed rating system identified 2,422 records with high-quality ages (i.e., a reduction of 74%). There are many applications of the database, including disentangling the confounding influences of hypothetical extinction drivers, better spatial distribution estimates of species relative to palaeo-climates, and potentially identifying new areas for fossil discovery

Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished

Tipping elements and amplified polar warming during the Last Interglacial

Irreversible shifts of large-scale components of the Earth system (so-called ‘tipping elements’) on policy-relevant timescales are a major source of uncertainty for projecting the impacts of future climate change. The high latitudes are particularly vulnerable to positive feedbacks that amplify change through atmosphere-ocean-ice interactions. Unfortunately, the short instrumental record does not capture the full range of past or projected climate scenarios (a situation particularly acute in the high latitudes). Natural archives from past periods warmer than present day, however, can be used to explore drivers and responses to forcing, and provide data against which to test models, thereby offering insights into the future. The Last Interglacial (129–116,000 years before present) — the warmest interglacial of the last 800,000 years — was the most recent period during which global temperatures were comparable with low-end 21st Century projections (up to 2 °C warmer, with temperature increase amplified over polar latitudes), providing a potentially useful analogue for future change. Substantial environmental changes happened during this time. Here we synthesise the nature and timing of potential high-latitude tipping elements during the Last Interglacial, including sea ice, extent of the boreal forest, permafrost, ocean circulation, and ice sheets/sea level. We also review the thresholds and feedbacks that likely operated through this period. Notably, substantial ice mass loss from Greenland, the West Antarctic, and possibly sectors of the East Antarctic drove a 6–9 m rise in global sea level. This was accompanied by reduced summer sea-ice extent, poleward-extended boreal forest, and reduced areas of permafrost. Despite current chronological uncertainties, we find that tipping elements in the high latitudes all experienced rapid and abrupt change (within 1–2 millennia of each other) across both hemispheres, while recovery to prior conditions took place over multi-millennia. Our synthesis demonstrates important feedback loops between tipping elements, amplifying polar and global change during the Last Interglacial. The high sensitivity and tight interconnections between polar tipping elements suggests that they could exhibit similar thresholds of vulnerability in the future, particularly if the aspirations of the Paris Agreement are not met

Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation.

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remain contentious, with major phases coinciding with both human arrival and climate change around the world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately, limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon data sets from the region. We identify a narrow megafaunal extinction phase 12,280 ± 110 years ago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediately prior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence and climate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts

Bayesian Estimation of Animal Movement from Archival and Satellite Tags

The reliable estimation of animal location, and its associated error is fundamental to animal ecology. There are many existing techniques for handling location error, but these are often ad hoc or are used in isolation from each other. In this study we present a Bayesian framework for determining location that uses all the data available, is flexible to all tagging techniques, and provides location estimates with built-in measures of uncertainty. Bayesian methods allow the contributions of multiple data sources to be decomposed into manageable components. We illustrate with two examples for two different location methods: satellite tracking and light level geo-location. We show that many of the problems with uncertainty involved are reduced and quantified by our approach. This approach can use any available information, such as existing knowledge of the animal's potential range, light levels or direct location estimates, auxiliary data, and movement models. The approach provides a substantial contribution to the handling uncertainty in archival tag and satellite tracking data using readily available tools

Long-Term GPS Tracking of Ocean Sunfish Mola mola Offers a New Direction in Fish Monitoring

Satellite tracking of large pelagic fish provides insights on free-ranging behaviour, distributions and population structuring. Up to now, such fish have been tracked remotely using two principal methods: direct positioning of transmitters by Argos polar-orbiting satellites, and satellite relay of tag-derived light-level data for post hoc track reconstruction. Error fields associated with positions determined by these methods range from hundreds of metres to hundreds of kilometres. However, low spatial accuracy of tracks masks important details, such as foraging patterns. Here we use a fast-acquisition global positioning system (Fastloc GPS) tag with remote data retrieval to track long-term movements, in near real time and position accuracy of <70 m, of the world's largest bony fish, the ocean sunfish Mola mola. Search-like movements occurred over at least three distinct spatial scales. At fine scales, sunfish spent longer in highly localised areas with faster, straighter excursions between them. These ‘stopovers’ during long-distance movement appear consistent with finding and exploiting food patches. This demonstrates the feasibility of GPS tagging to provide tracks of unparalleled accuracy for monitoring movements of large pelagic fish, and with nearly four times as many locations obtained by the GPS tag than by a conventional Argos transmitter. The results signal the potential of GPS-tagged pelagic fish that surface regularly to be detectors of resource ‘hotspots’ in the blue ocean and provides a new capability for understanding large pelagic fish behaviour and habitat use that is relevant to ocean management and species conservation

DNA Barcoding Bromeliaceae: Achievements and Pitfalls

<div><h3>Background</h3><p>DNA barcoding has been successfully established in animals as a tool for organismal identification and taxonomic clarification. Slower nucleotide substitution rates in plant genomes have made the selection of a DNA barcode for land plants a much more difficult task. The Plant Working Group of the Consortium for the Barcode of Life (CBOL) recommended the two-marker combination <em>rbcL</em>/<em>matK</em> as a pragmatic solution to a complex trade-off between universality, sequence quality, discrimination, and cost.</p> <h3>Methodology/Principal Findings</h3><p>It is expected that a system based on any one, or a small number of plastid genes will fail within certain taxonomic groups with low amounts of plastid variation, while performing well in others. We tested the effectiveness of the proposed CBOL Plant Working Group barcoding <em>markers</em> for land plants in identifying 46 bromeliad species, a group rich in endemic species from the endangered Brazilian Atlantic Rainforest. Although we obtained high quality sequences with the suggested primers, species discrimination in our data set was only 43.48%. Addition of a third marker, <em>trnH–psbA</em>, did not show significant improvement. This species identification failure in Bromeliaceaecould also be seen in the analysis of the GenBank's <em>matK</em> data set. Bromeliaceae's sequence divergence was almost three times lower than the observed for Asteraceae and Orchidaceae. This low variation rate also resulted in poorly resolved tree topologies. Among the three Bromeliaceae subfamilies sampled, Tillandsioideae was the only one recovered as a monophyletic group with high bootstrap value (98.6%). Species paraphyly was a common feature in our sampling.</p> <h3>Conclusions/Significance</h3><p>Our results show that although DNA barcoding is an important tool for biodiversity assessment, it tends to fail in taxonomy complicated and recently diverged plant groups, such as Bromeliaceae. Additional research might be needed to develop markers capable to discriminate species in these complex botanical groups.</p> </div

Accuracy of Using Visual Identification of White Sharks to Estimate Residency Patterns

Determining the residency of an aquatic species is important but challenging and it remains unclear what is the best sampling methodology. Photo-identification has been used extensively to estimate patterns of animals' residency and is arguably the most common approach, but it may not be the most effective approach in marine environments. To examine this, in 2005, we deployed acoustic transmitters on 22 white sharks (Carcharodon carcharias) in Mossel Bay, South Africa to quantify the probability of detecting these tagged sharks by photo-identification and different deployment strategies of acoustic telemetry equipment. Using the data collected by the different sampling approaches (detections from an acoustic listening station deployed under a chumming vessel versus those from visual sightings and photo-identification), we quantified the methodologies' probability of detection and determined if the sampling approaches, also including an acoustic telemetry array, produce comparable results for patterns of residency. Photo-identification had the lowest probability of detection and underestimated residency. The underestimation is driven by various factors primarily that acoustic telemetry monitors a large area and this reduces the occurrence of false negatives. Therefore, we propose that researchers need to use acoustic telemetry and also continue to develop new sampling approaches as photo-identification techniques are inadequate to determine residency. Using the methods presented in this paper will allow researchers to further refine sampling approaches that enable them to collect more accurate data that will result in better research and more informed management efforts and policy decisions

The World's Rediscovered Species: Back from the Brink?

Each year, numerous species thought to have disappeared are rediscovered. Yet, do these rediscoveries represent the return of viable populations or the delayed extinction of doomed species? We document the number, distribution and conservation status of rediscovered amphibian, bird, and mammal species globally. Over the past 122 years, at least 351 species have been rediscovered, most occurring in the tropics. These species, on average, were missing for 61 years before being rediscovered (range of 3–331 years). The number of rediscoveries per year increased over time and the majority of these rediscoveries represent first documentations since their original description. Most rediscovered species have restricted ranges and small populations, and 92% of amphibians, 86% of birds, and 86% of mammals are highly threatened, independent of how long they were missing or when they were rediscovered. Under the current trends of widespread habitat loss, particularly in the tropics, most rediscovered species remain on the brink of extinction