Biology subjects

Isaac, N. J. B.

Publications and source records attributed to Isaac, N. J. B..

5 recordsLinked to original sources

bioRxiv2022

EDGE2: advancing the prioritisation of threatened evolutionary history for conservation action

The global biodiversity crisis threatens the natural world and its capacity to provide benefits to humans into the future. The conservation of evolutionary history, captured by the measure phylogenetic diversity (PD), is linked to the maintenance of these benefits and future options. The Evolutionarily Distinct and Globally Endangered (EDGE) metric has, since 2007, been used to identify species for conservation action that embody large amounts of threatened evolutionary history. In 2017, we convened a workshop to update the EDGE metric to incorporate advances in the field of phylogenetically-informed conservation. Building on that workshop, we devised the metric EDGE2, which we present here. EDGE2 uses a modular, tiered approach to provide priority rankings--and associated measures of uncertainty in both phylogenetic and extinction risk data--for all species in a clade. EDGE2 takes into account the extinction risk of closely-related species to better reflect the contribution a species is expected to make to overall PD in the future. We applied EDGE2 to the worlds mammals to identify an updated list of priority EDGE species and compare the results with the original EDGE approach. Despite similarity in the priority lists produced between EDGE and EDGE2, EDGE2 places greater priority on species with fewer close relatives on the Tree of Life. As we approach a crossroads for global biodiversity policy, EDGE2 exemplifies how academic and applied conservation biologists can collaborate to guide effective priority-setting to conserve the most irreplaceable components of biodiversity upon which humanity depends.

zoology↗

bioRxiv2022

CaPTrends: A global database of Carnivoran Population Trends

MotivationPopulation trend information is an Essential Biodiversity Variable for monitoring change in biodiversity over time. Here, we present a global dataset of 1122 population trends describing changes in abundance over time in large mammals from the Order Carnivora - some of the worlds most charismatic and functionally important fauna. Main types of variables includedKey data fields for each record: species, coordinates, trend timeframe, methods of data collection and analysis, and population timeseries or summarised trend value. Population trend values are reported using quantitative metrics in 75% of records that collectively represent more than 6500 population estimates. The remaining records qualitatively describe population change (e.g. increase). Spatial location and grainRecords represent locations across the globe (latitude: -51.0 to 80.0; longitude: -166.0 to 166.0) with more trends found within the northern temperate zone. Time period and grainRecords span from 1726 to 2017, with 92% of trends starting after 1950. Major taxa and level of measurementWe conducted a semi-systematic search for population trend data in 87 species from four families in the order Carnivora: Canidae, Felidae, Hyaenidae and Ursidae. We compiled data for 50 of the 87 species. Software format.csv

ecology↗

bioRxiv2021

Socioeconomics drive population change in the world's largest carnivores

Land-use1,2 and climate change3-5 have been linked to wildlife population declines, but the role of socioeconomic factors in driving declines, and promoting population recoveries, remains relatively unexplored despite its likely importance. Here, we evaluate a comprehensive array of potential drivers of population changes observed in some of the worlds most charismatic species - large mammalian carnivores. Our results reveal a strong role of human socioeconomic development, which we find has a greater impact on population change than habitat loss and climate change. Increases in socioeconomic development are linked to sharp population declines but, importantly, once development is high, carnivore populations have the potential to recover. These links between human development and wildlife population health highlight the challenges ahead to achieve the different UN Sustainable development goals.

ecology↗

bioRxiv2020

Rapid Anthropocene realignment of allometric scaling rules

The negative relationship between body size and population density (SDR) in mammals is often interpreted as resulting from energetic constraints. In a global change scenario, however, this relationship might be expected to change, given the size-dependent nature of anthropogenic pressures and vulnerability to extinction. Here we test whether the SDR in mammals has changed over the last 50 years. We show that the relationship has shifted down and became shallower, corresponding to a decline in population density of 32-72%, for the largest and smallest mammals, respectively. However, the SDRs become steeper in some groups (e.g. carnivores) and shallower in others (e.g. herbivores). The Anthropocene reorganization of biotic systems is apparent in macroecological relationships that were previously believed to be immutable, reinforcing the notion that biodiversity pattens are contingent upon conditions at the time of investigation. We call for an increased attention on the role of global change on macroecological inferences.

ecology↗

bioRxiv2019

Rapid assessment of the suitability of multi-species citizen science datasets for occupancy trend analysis

O_LISpecies records from volunteers are a vast and valuable source of information on biodiversity for a wide range of taxonomic groups. Although these citizen science data are opportunistic and unstructured, occupancy analysis can be used to quantify trends in distribution. However, occupancy analysis of unstructured data can be resource-intensive and requires substantial expertise. It is valuable to have simple rules of thumb to efficiently assess the suitability of a dataset for occupancy analysis prior to analysis.\nC_LIO_LIOur analysis was possible due to the production of trends, from our Bayesian occupancy analysis, for 10 967 species from 34 multi-species recording schemes in Great Britain. These schemes had an average of 500 visits to sites per year, and an average of 20% of visited sites received a revisit in a year. Occupancy trend outputs varied in their precision and we used expert elicitation on a subset of outputs to determine a precision threshold above which trends were suitable for further consideration. We then used classification trees with seven metrics to define simple rules explaining when the data would result in outputs that met the precision threshold.\nC_LIO_LIWe found that the suitability of a species data was best described by (i) the number of records of the focal species in the 10% best-recorded years, and (ii) the proportion of recording visits for that taxonomic group with non-detections of the focal species. Surprisingly few data were required to be predicted to meet the precision threshold. Specifically, for 98% confidence that our Bayesian occupancy models would produce outputs meeting the precision threshold, there needed to be [≥]29 records of the focal species in the 10% best-recorded years (equivalent to an average of 12.5 records per year in our dataset), although only [≥]10 records (equivalent to 4.5 records per year) were required for species recorded in less than 1 in 25 visits.\nC_LIO_LIWe applied these rules to regional species data for Great Britain. Data from 32% of the species:region combinations met the precision threshold with 80% confidence, and 14% with 98% confidence. There was great variation between taxonomic groups (e.g. butterflies, moths and dragonflies were well recorded) and region (e.g. south-east England was best recorded).\nC_LIO_LIThese simple criteria provide no indication of the accuracy or representativeness of the trend outputs: this is vital, but needs to be assessed individually. However our criteria do provide a rapid, quantitative assessment of the predicted suitability of existing data for occupancy analysis and could be used to inform the design and implementation of multi-species citizen science recording projects elsewhere in the world.\nC_LI

ecology↗