Biology subjects

Nipperess, D. A.

Publications and source records attributed to Nipperess, D. A..

4 recordsLinked to original sources

bioRxiv2022

How exposure to land use impacts and climate change may prune the tetrapod tree of life

Human domination of landscapes is a key driver of biodiversity loss, with the fingerprint of climate change becoming increasingly pronounced. Frameworks and tools for identifying threats to biodiversity are required to meet Post-2020 Global Biodiversity Framework targets for 2030 that call for, among other things, reducing or halting species extinction rates (1). Hence, we compiled a phylogenetic tree for terrestrial tetrapods, mapped hotspots of geographically restricted and evolutionarily distinct lineages, and identified which hotspots may simultaneously face the highest magnitudes of land use impacts and climate change. Across a quarter of Earths surface, hotspots contain the entire ranges of 45% of tetrapods, representing 39% of terrestrial tetrapod evolutionary heritage. By 2070, we estimate 8-13% of this heritage to occur entirely within hotspots highly exposed to climate change, with 13-29% of hotspots projected to experience high exposure to both stressors simultaneously. Most hotspots at highest risk occur in countries least able to take action. Our analysis highlights the need for global ambition and coordination to avoid catastrophic loss of tetrapod evolutionary heritage.

ecology↗

bioRxiv2021

Climate-change risk analysis for global urban forests

Urban forests (i.e. all vegetation present in urban areas), provide environmental and socioeconomic benefits1 to more than half of the global population2. Projected climate change threatens these benefits to society3-5. Here, we assess vulnerability to climate change of 16,006 plant species present in the urban forests of 1,010 cities within 93 countries, using three vulnerability metrics: exposure, safety margin and risk. Exposure expresses the magnitude of projected changes in climate in a given area, safety margin measures species sensitivity to climate change, and risk is the difference between exposure and safety margin6. We identified 9,676 (60.5%) and 8,344 (52.1%) species exceeding their current climatic tolerance (i.e. safety margin) for mean annual temperature (MAT) and annual precipitation (AP), respectively. By 2050, 13,479 (84.2%) and 9,960 (62.2%) species are predicted to be at risk from projected changes in MAT and AP, respectively, with risk increasing in cities at lower latitudes. Our results can aid evaluation of the impacts of climate change on urban forests and identify the species most at risk. Considering future climates when selecting species for urban plantings will enhance the long-term societal benefits provided by urban forests, including their contribution to mitigating the magnitude and impacts of climate change.

ecology↗

bioRxiv2017

The application of zeta diversity as a continuous measure of compositional change in ecology

Zeta diversity provides the average number of shared species across n sites (or shared operational taxonomic units (OTUs) across n cases). It quantifies the variation in species composition of multiple assemblages in space and time to capture the contribution of the full suite of narrow, intermediate and wide-ranging species to biotic heterogeneity. Zeta diversity was proposed for measuring compositional turnover in plant and animal assemblages, but is equally relevant for application to any biological system that can be characterised by a row by column incidence matrix. Here we illustrate the application of zeta diversity to explore compositional change in empirical data, and how observed patterns may be interpreted. We use 10 datasets from a broad range of scales and levels of biological organisation - from DNA molecules to microbes, plants and birds - including one of the original data sets used by R.H. Whittaker in the 1960s to express compositional change and distance decay using beta diversity. The applications show (i) how different sampling schemes used during the calculation of zeta diversity may be appropriate for different data types and ecological questions, (ii) how higher orders of zeta may in some cases better detect shifts, transitions or periodicity, and importantly (iii) the relative roles of rare versus common species in driving patterns of compositional change. By exploring the application of zeta diversity across this broad range of contexts, our goal is to demonstrate its value as a tool for understanding continuous biodiversity turnover and as a metric for filling the empirical gap that exists on spatial or temporal change in compositional diversity.

ecology↗

bioRxiv2017

Generalised Complementarity Analysis: identifying the most preciousplaces for the conservation of Species, Functional and PhylogeneticDiversity

The most precious places for conservation are those that make the largest contribution to regional, national or global biodiversity. The two key concepts for determining the contribution of a specific site are Complementarity (the gain in diversity achieved when adding that site to a set of other sites) and Irreplaceability (here defined as the overall complementarity of that site when compared to a range of possible combinations of other sites). Generalised Complementarity Analysis (GCA) is a mathematical framework that provides an exact analytical solution for the expected complementarity (gain in diversity) of a focal site, when added to a set of other sites of a given size (m). Diversity is defined very generally to allow for complementarity to be calculated for species richness, Functional Diversity or Phylogenetic Diversity. The expected irreplaceability of a focal site is then defined in GCA as the area under the curve of expected complementarity values for all possible values of m. GCA is much more computationally efficient than existing algorithmic approaches and is scalable to very large numbers of sites. Because complementarity and irreplaceability are calculated for all possible combinations of sites, GCA serves as a null model for systematic conservation planning algorithms that seek to optimise site selection. However, because truly irreplaceable sites remain so under all possible site selections, GCA is a powerful conservation planning tool in its own right, providing an efficient means of identifying the worlds most precious places for conservation.

ecology↗