Earth Day 2021

Oita, Arnold and colleagues investigate the interplay between abiotic and biotic factors in lowland forest microbial communities. Their results indicate that endophyte richness negatively correlates with temperature seasonality. Both biotic and abiotic factors should be considered when studying endophyte community diversity drivers.

Gillespie et al. perform drying-rewetting experiments in soil microcosms from European forests and find that microbial communities from mixed tree species forests resist drought better than those from single species forests. These results show that tree diversity mitigates drought effects on soil microbial processes and may promote biogeochemical stability in order to resist future drought.

By performing an ecologically relevant experiment with variety in litter composition and detritivore species, Joly et al. find that litter conversion into faeces has a profound effect on organic matter lability and decomposition. These findings have implications for biogeochemical models of carbon cycling.

Xu et al. examine the effect of leguminous trees on neighbor diversity across 11 plots in tropical forests around the world, and find that in high soil nitrogen conditions, most legume species have higher neighbor diversity than non-legumes, and vice versa where soil nitrogen is low. Their results have practical implications for the utilization of legumes in forest restoration.

Jingyu Dai et al. study the role of tree allometry in maintaining a high carbon sequestration. They measure allometry in semi-arid forests using terrestrial laser scanning. They report that tree height as well as canopy area decline to varying degrees among individuals. They provide insights on how trees balance water consumption and carbon assimilation which enhances the survival rate of the forest trees.

Yunke Peng et al. use in-situ measurements and leaf trait data at 266 global sites for 1637 species and find that the maximum rate of carboxylation standardized to 25 °C is proportional to growing-season irradiance, and covaries with area-based leaf nitrogen and area-based phosphorus on the species level. These results challenge the assumption that leaf-level photosynthetic capacity depends on soil N supply yet supports the relationship between photosynthesis and soil P supply.

Stef Bokhorst et al. simulate a warming scenario in Antarctic soil under laboratory conditions and report the germination and growth of sixteen non-native plant species. These experimental results, combined with calculations of thermal germination requirement at +3 °C and +5 °C warming scenarios demonstrate that the risk of establishment by non-native species in Antarctica may be greater than previously suggested by species distribution modelling approaches.

Lisa Crozier et al. assembled a database for eight wild populations of threatened Chinook salmon in the Salmon River Basin in order to evaluate climate impacts at all life stages, and model future population trajectories. They project that populations rapidly decline in response to increasing sea surface temperatures and conclude that dramatic increases in the number or survival of smolts are needed to overcome the negative impacts of climate change for this threatened species.

Zhi Wang et al. compare benthic surveys before and after the bottom trawling ban in Hong Kong in 2012 and demonstrate abiotic changes in sediment as well as macrobenthos diversity. These results showed that benthic communities were less fragmented following the ban and indicate trawling bans as an effective measure to restore biodiversity to tropical coastal waters.

Julián Velasco et al. use climate model simulations to show how the collapse of the Atlantic meridional overturning circulation and unabated global warming under the RCP 8.5 scenario affect the global distribution of 2509 amphibian species. These results show severe and synergistic impacts of global warming, with particularly strong effects shown in the Neotropical, Nearctic and Palearctic regions.

Petraitis and Dudgeon report a decline in mussel and gastropod abundance and recruitment on rocky intertidal shores of the Gulf of Maine over a period of 20 years. These declines are correlated with increased water temperatures and aragonite saturation state, which affects rates of shell calcification, and suggests environmental impacts on the food webs of rocky shores.

Roberts et al. use over 30 years of data and nearly 100 fish species to document changes in distribution over time in conjunction with environmental data. Their results show that fish species whose distributions are more associated with bottom substrate were less likely to shift relative to species whose distributions are associated with bottom salinity and temperature, and have implications for future distribution response to climate change.

Guillaume Peterson St-Laurent et al. introduce the R–R-T (Resistance-Resilience-Transformation) conservation typology that enables the empirical assessment of whether and to what extent a management shift toward transformative action is occurring. They apply the R–R-T scale to 104 adaptation projects and find a shift towards transformation over time and differential responses across ecosystems, with more transformative actions applied in forested ecosystems.

Laura Jones et al. compare honey samples across the UK from 2017 to a nationwide survey of honey samples from 1952 in order to determine how nectar and pollen sources have changed over time. They find that shifts in major plants foraged by honeybees are driven by changes in the availability of these plants within the landscape, and focus on improved grasslands as the most widespread habitat type and a potential target for management efforts to increase floral resource availability.

Eduardo Moreno-Jiménez et al. experimentally manipulate rainfall and temperature in a Mediterranean dryland to explore the association of biocrusts with essential metallic nutrients. They find that biocrusts—communities of lichens, bryophytes and cyanobacteria on the soil surface—can buffer against the effects of warming and reduced rainfall on metallic nutrient availability.

Nuria Melisa Morales-García et al. analyze jaw shape and mechanical advantage of 70 small modern mammals and 45 Mesozoic mammals and find that these metrics can be used to distinguish dietary groups for most extant mammals, and to infer diet in Mesozoic taxa.

A new fossil of a vampire squid bridges a 120 million-year gap in their fossil record. Vampire squid today are adapted to low oxygen, deep sea environments and this new specimen provides evidence that the deep sea specialisation of vampire squid may have been triggered during the development of oxygen minimum zones in the oceans during the Cretaceous and Cenozoic.

Lammers et al. use sedimentary ancient DNA to reconstruct palaeogenomes of Nannochloropsis. This study demonstrates the value of sedaDNA for palaeogenomic reconstructions and population genomic analysis.

Jonathan Goldenberg et al. use photographic data and ancestral state reconstruction of 126 viper species to show that substrate type influences the evolution of ventral brightness for efficient heat transfer. Their results suggest that these patterns may have been involved in the diversification of vipers during the Miocene, and highlight the importance of ventral body regions when considering behavioral ecology and evolution.

Using species range data, phylogenies, and fossil records of thousands of extinct and extant terrestrial vertebrates, He et al. quantify temporal changes in beta dissimilarities among zoogeographical regions surrounding the Tibetan Plateau during the Cenozoic era. This study shows how geological events underpin the evolutionary history of zoogeographical regions.

de Medeiros and Farrell test how insect-host interactions influence species divergence in phytophagous insects. Using ddRAD-seq data and hierarchical modelling, they demonstrate, surprisingly, that antagonistic interactions between insect and host do not lead to greater species diversification.

Michael Donovan et al. examine well-preserved remains of diverse insect-feeding and fungal damage on Patagonian fossil and extant material of the conifer Agathis. They report a suite of blotch mines, galls, scale-insect covers, and rust fungus that re-occur on the same host genus through time and space, showing the persistence of ecological guilds and possible host-tracking across major plate movements since the late Mesozoic.

The Doushantuo biota of China is incredibly important for understanding the evolution of complex animals. Willman et al. report on evidence of Doushantuo-like biota from the Ediacaran of North Greenland, indicating that these important organisms were distributed across multiple palaeocontinents.

Rojas et al. present a new multi-scale model that reveals the three major biotic transitions of the Phanerozoic fossil record. This new model supports the hypothesis that both long-term ecological changes and major geological events played crucial roles in shaping ocean mega-assemblages through the Phanerozoic.

Jonathas Bittencourt et al. report the discovery of a fossil lizard in South America dated to at least 130 mya, about 20 million years earlier than previously thought. This finding suggests early lizards in South America were much more broadly distributed than extant species in this region.