The price of conserving avian phylogenetic diversity: a global prioritization approach

The combination of rapid biodiversity loss and limited funds available for conservation represents a major global concern. While there are many approaches for conservation prioritization, few are framed as financial optimization problems. We use recently published avian data to conduct a global analysis of the financial resources required to conserve different quantities of phylogenetic diversity (PD). We introduce a new prioritization metric (ADEPD) that After Downlisting a species gives the Expected Phylogenetic Diversity at some future time. Unlike other metrics, ADEPD considers the benefits to future PD associated with downlisting a species (e.g. moving from Endangered to Vulnerable in the International Union for Conservation of Nature Red List). Combining ADEPD scores with data on the financial cost of downlisting different species provides a cost-benefit prioritization approach for conservation. We find that under worst-case spending $3915 can save 1 year of PD, while under optimal spending$1 can preserve over 16.7 years of PD. We find that current conservation spending patterns are only expected to preserve one quarter of the PD that optimal spending could achieve with the same total budget. Maximizing PD is only one approach within the wider goal of biodiversity conservation, but our analysis highlights more generally the danger involved in uninformed spending of limited resources

The Neutral-Niche Debate:A Philosophical Perspective

Ecological communities around the world are under threat while a consensus theory of community structure remains elusive. In the last decade ecologists have struggled with two seemingly opposing theories: niche-based theory that explains diversity with species’ differences and the neutral theory of biodiversity that claims that much of the diversity we observe can be explained without explicitly invoking species’ differences. Although ecologists are increasingly attempting to reconcile these two theories, there is still much resistance against the neutral theory of biodiversity. Here we argue that the dispute between the two theories is a classic example of the dichotomy between philosophical perspectives, realism and instrumentalism. Realism is associated with specific, small-scale and detailed explanations, whereas instrumentalism is linked to general, large-scale, but less precise accounts. Recognizing this will help ecologists get both niche-based and neutral theories in perspective as useful tools for understanding biodiversity patterns

Grayanotoxin I variation across tissues and species of Rhododendron suggests pollinator-herbivore defence trade-offs

Grayanotoxin I (GTX I) is a major toxin in leaves of Rhododendron species, where it provides a defence against insect and vertebrate herbivores. Surprisingly, it is also present in R. ponticum nectar, and this can hold important implications for plant-pollinator mutualisms. However, knowledge of GTX I distributions across the genus Rhododendron and in different plant materials is currently limited, despite the important ecological function of this toxin. Here we characterise GTX I expression in the leaves, petals, and nectar of seven Rhododendron species. Our results indicated interspecific variation in GTX I concentration across all species. GTX I concentrations were consistently higher in leaves compared to petals and nectar. Our findings provide preliminary evidence for phenotypic correlation between GTX I concentrations in defensive tissues (leaves and petals) and floral rewards (nectar), suggesting that Rhododendron species may commonly experience functional trade-offs between herbivore defence and pollinator attraction

Integrating ecology into macroevolutionary research

On 9 March, over 150 biologists gathered in London for the Centre for Ecology and Evolution spring symposium, ‘Integrating Ecology into Macroevolutionary Research’. The event brought together researchers from London-based institutions alongside others from across the UK, Europe and North America for a day of talks. The meeting highlighted methodological advances and recent analyses of exemplar datasets focusing on the exploration of the role of ecological processes in shaping macroevolutionary patterns

Grayanotoxin I variation across different tissues and species of Rhododendron suggest herbivore defence trade-offs

Grayanotoxin I (GTX I) is a major toxin in leaves of Rhododendron species, where it provides a defence against insect and vertebrate herbivores. Surprisingly, it is also present in R. ponticum nectar, and this can hold important implications for plant-pollinator mutualisms. However, knowledge of GTX I distributions across the genus Rhododendron and in different plant materials is currently limited, despite the important ecological function of this toxin. Here we characterise GTX I expression in the leaves, petals, and nectar of seven Rhododendron species. Our results indicated interspecific variation in GTX I concentration across all species.GTX I concentrations were consistently higher in leaves compared to petals and nectar. Our findings provide preliminary evidence for phenotypic correlation between GTX I concentrations in defensive tissues (leaves and petals) and floral rewards (nectar), suggesting that Rhododendron species may commonly experience functional trade-offs between herbivore defence and pollinator attraction

The Spatial Limitations of Current Neutral Models of Biodiversity

The unified neutral theory of biodiversity and biogeography is increasingly accepted as an informative null model of community composition and dynamics. It has successfully produced macro-ecological patterns such as species-area relationships and species abundance distributions. However, the models employed make many unrealistic auxiliary assumptions. For example, the popular spatially implicit version assumes a local plot exchanging migrants with a large panmictic regional source pool. This simple structure allows rigorous testing of its fit to data. In contrast, spatially explicit models assume that offspring disperse only limited distances from their parents, but one cannot as yet test the significance of their fit to data. Here we compare the spatially explicit and the spatially implicit model, fitting the most-used implicit model (with two levels, local and regional) to data simulated by the most-used spatially explicit model (where offspring are distributed about their parent on a grid according to either a radially symmetric Gaussian or a ‘fat-tailed’ distribution). Based on these fits, we express spatially implicit parameters in terms of spatially explicit parameters. This suggests how we may obtain estimates of spatially explicit parameters from spatially implicit ones. The relationship between these parameters, however, makes no intuitive sense. Furthermore, the spatially implicit model usually fits observed species-abundance distributions better than those calculated from the spatially explicit model's simulated data. Current spatially explicit neutral models therefore have limited descriptive power. However, our results suggest that a fatter tail of the dispersal kernel seems to improve the fit, suggesting that dispersal kernels with even fatter tails should be studied in future. We conclude that more advanced spatially explicit models and tools to analyze them need to be developed

Diversification of flowering plants in space and time

The rapid diversification and high species richness of flowering plants is regarded as ‘Darwin’s second abominable mystery’. Today the global spatiotemporal pattern of plant diversification remains elusive. Using a newly generated genus-level phylogeny and global distribution data for 14,244 flowering plant genera, we describe the diversification dynamics of angiosperms through space and time. Our analyses show that diversification rates increased throughout the early Cretaceous and then slightly decreased or remained mostly stable until the end of the Cretaceous–Paleogene mass extinction event 66 million years ago. After that, diversification rates increased again towards the present. Younger genera with high diversification rates dominate temperate and dryland regions, whereas old genera with low diversification dominate the tropics. This leads to a negative correlation between spatial patterns of diversification and genus diversity. Our findings suggest that global changes since the Cenozoic shaped the patterns of flowering plant diversity and support an emerging consensus that diversification rates are higher outside the tropics