Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders

Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity

Specialization in Plant-Hummingbird Networks Is Associated with Species Richness, Contemporary Precipitation and Quaternary Climate-Change Velocity

Bo Dalsgaard et al...Large-scale geographical patterns of biotic specialization and the underlying drivers are poorly understood, but it is widely believed that climate plays an important role in determining specialization. As climate-driven range dynamics should diminish local adaptations and favor generalization, one hypothesis is that contemporary biotic specialization is determined by the degree of past climatic instability, primarily Quaternary climate-change velocity. Other prominent hypotheses predict that either contemporary climate or species richness affect biotic specialization. To gain insight into geographical patterns of contemporary biotic specialization and its drivers, we use network analysis to determine the degree of specialization in plant-hummingbird mutualistic networks sampled at 31 localities, spanning a wide range of climate regimes across the Americas. We found greater biotic specialization at lower latitudes, with latitude explaining 20–22% of the spatial variation in plant-hummingbird specialization. Potential drivers of specialization - contemporary climate, Quaternary climate-change velocity, and species richness - had superior explanatory power, together explaining 53–64% of the variation in specialization. Notably, our data provides empirical evidence for the hypothesized roles of species richness, contemporary precipitation and Quaternary climate-change velocity as key predictors of biotic specialization, whereas contemporary temperature and seasonality seem unimportant in determining specialization. These results suggest that both ecological and evolutionary processes at Quaternary time scales can be important in driving large-scale geographical patterns of contemporary biotic specialization, at least for co-evolved systems such as plant-hummingbird networks.Funding for BD was supported by Frimodt-Heineke Foundation, Augustinus Foundation, Knud Højgaard Foundation, a PhD fellowship by Aarhus University, Weis-Fogh Fund at Department of Zoology, University of Cambridge, and The Danish Council for Independent Research | Natural Sciences. EM was supported by the Center for Massive Data Algorithmics, a Danish National Research Foundation Center of Excellence. JF and CR thank the Danish National Research Foundation for its support of the Center for Macroecology, Evolution and Climate. AMG was supported by Svend Fiedler & Wife Foundation, J.Olesen by the Danish Council for Independent Research - Natural Sciences and Novozymes/World Wildlife Foundation-Denmark, J.Ollerton and SW by the British Ecological Society, Idea Wild, The Biodiversity Trust, The Anglo Peruvian Society and The Leslie Church Bursary Fund, RA by The United States National Science Foundation's Predoctoral Fellowship Program and The California Alliance for Minority Participation, ACA by The Fundação de Amparo à Pesquisa do Estado da Bahia (FAEP) and The National Council for Scientific and Technological Development (CNPq), PC by the British Ornithologists' Union, CL by the Consejo Nacional de Ciencia y Tecnología, CM by FAPESB and CNPq, IS and MS by FAPESP and CNPq, AT by Aarhus University, and J-CS by the Danish Council for Independent Research - Natural Sciences (grant 272-07-0242). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

African Environmental Change from the Pleistocene to the Anthropocene

This review explores what past environmental change in Africa—and African people\u27s response to it—can teach us about how to cope with life in the Anthropocene. Organized around four drivers of change—climate; agriculture and pastoralism; megafauna; and imperialism, colonialism, and capitalism (ICC)—our review zooms in on key regions and debates, including desertification; rangeland degradation; megafauna loss; and land grabbing. Multiscale climate change is a recurring theme in the continent\u27s history, interacting with increasingly intense human activities from several million years onward, leading to oscillating, contingent environmental changes and societally adaptive responses. With high levels of poverty, fast population growth, and potentially dramatic impacts expected from future climate change, Africa is emblematic of the kinds of social and ecological precariousness many fear will characterize the future globally. African people\u27s innovation and adaptation to contingency may place them among the avant-garde with respect to thinking about Anthropocene conditions, strategies, and possibilities

Climate warming has compounded plant responses to habitat conversion in northern Europe

Serious concerns exist about potentially reinforcing negative effects of climate change and land conversion on biodiversity. Here, we investigate the tandem and interacting roles of climate warming and land-use change as predictors of shifts in the regional distributions of 1701 plant species in Sweden over 60 years. We show that species associated with warmer climates have increased, while grassland specialists have declined. Our results also support the hypothesis that climate warming and vegetation densification through grazing abandonment have synergistic effects on species distribution change. Local extinctions were related to high levels of warming but were reduced by grassland retention. In contrast, colonisations occurred more often in areas experiencing high levels of both climate and land-use change. Strong temperature increases were experienced by species across their ranges, indicating time lags in expected warming-related local extinctions. Our results highlight that the conservation of threatened species relies on both reduced greenhouse gas emissions and the retention and restoration of valuable habitat

Habitat productivity constrains the distribution of social spiders across continents – case study of the genus Stegodyphus

INTRODUCTION: Sociality has evolved independently multiple times across the spider phylogeny, and despite wide taxonomic and geographical breadth the social species are characterized by a common geographical constrain to tropical and subtropical areas. Here we investigate the environmental factors that drive macro-ecological patterns in social and solitary species in a genus that shows a Mediterranean–Afro-Oriental distribution (Stegodyphus). Both selected drivers (productivity and seasonality) may affect the abundance of potential prey insects, but seasonality may further directly affect survival due to mortality caused by extreme climatic events. Based on a comprehensive dataset including information about the distribution of three independently derived social species and 13 solitary congeners we tested the hypotheses that the distribution of social Stegodyphus species relative to solitary congeners is: (1) restricted to habitats of high vegetation productivity and (2) constrained to areas with a stable climate (low precipitation seasonality). RESULTS: Using spatial logistic regression modelling and information-theoretic model selection, we show that social species occur at higher vegetation productivity than solitary, while precipitation seasonality received limited support as a predictor of social spider occurrence. An analysis of insect biomass data across the Stegodyphus distribution range confirmed that vegetation productivity is positively correlated to potential insect prey biomass. CONCLUSIONS: Habitat productivity constrains the distribution of social spiders across continents compared to their solitary congeners, with group-living in spiders being restricted to areas with relatively high vegetation productivity and insect prey biomass. As known for other taxa, permanent sociality likely evolves in response to high predation pressure and imposes within-group competition for resources. Our results suggest that group living is contingent upon productive environmental conditions where elevated prey abundance meet the increased demand for food of social groups

Light converts endosymbiotic fungus to pathogen, influencing seedling survival and host tree recruitment

Endophytic fungi that asymptomatically colonize plants^1^ are diverse and abundant in tropical ecosystems^2^. These organisms can be weakly pathogenic^3^ and/or mutualistic, frequently enabling plants to adapt to extreme environments, alter competitive abilities of host individuals and improve host fitness under abiotic or biotic stresses^4,5,6^. _Diplodia mutila_ is a symbiotic endophyte/plant pathogenic fungus infecting the palm _Iriartea deltoidea_^7^, which dominates many wet lowland Neotropical forests. The fungus is an asymptomatic endophyte in mature plants, and disease and mortality are expressed in some seedlings, while others remain disease free. Here we show that seedlings bearing the endophyte show enhanced resistance to insect herbivory. However, high light availability triggers pathogenicity of the fungus, while low light favors endosymbiotic development, constraining recruitment of endophyte-infested seedlings to the shaded understory by limiting survival of seedlings in direct light. These results provide evidence that patterns of plant abundance and the mechanisms maintaining tropical forest biodiversity are the result of a more complex interplay between abiotic and biotic environments than previously thought