Drivers of the global phosphorus cycle over geological time
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The role of rivers in the origin and future of Amazonian biodiversity
The rich biodiversity of Amazonia is shaped geographically and ecologically by its rivers and their cycles of seasonal flooding. Anthropogenic effects, such as deforestation, infrastructure development and extreme climatic events, threaten the ecological processes sustaining Amazonian ecosystems. In this Review, we explore the coupled evolution of Amazonian rivers and biodiversity associated with terrestrial and seasonally flooded environments, integrating geological, climatic, ecological and genetic evidence. Amazonia and its fluvial environments are highly heterogeneous, and the drainage system is historically dynamic and continually evolving; as a result, the discharge, sediment load and strength of rivers as barriers to biotic dispersal has changed through time. Ecological affinities of taxa, drainage rearrangements and variations in riverine landscape caused by past climate changes have mediated the evolution of the high diversity found in modern-day Amazonia. The connected history of the region’s biodiversity and landscape provides fundamental information for mitigating current and future impacts. However, incomplete knowledge about species taxonomy, distributions, habitat use, ecological interactions and occurrence patterns limits our understanding. Partnerships with Indigenous peoples and local communities, who have close ties to land and natural resources, are key to improving knowledge generation and dissemination, enabling better impact assessments, monitoring and management of the riverine systems at risk from evolving pressures.
Discrete fracture network modelling reconstructs fracture array evolution and related petrophysical properties over geological time
Fractured rock petrophysical studies rarely use temporal constraints, thus hindering fracture-related permeability and connectivity estimation during past geofluid migration. Here we present a conceptual approach, using a stochastic method incorporating absolute ages to reconstruct fracture arrays back in geological time. Generating ‘grown’ discrete fracture network models, we simulate the hydraulic behaviour of fractured rock volumes from the late-Cretaceous/Palaeocene to the Devonian, via progressive fracture back-stripping. We reveal that for the examined rock mass, maximum principal permeability increased through time from 9.47e-14 m2 to 4.44e-13 m2 (~3 orders of magnitude) along with the maximum horizontal permeability orientation shifting from NE-SW to NW-SE. Similarly, the connectivity metric increased with fracture saturation, peaking in the mid-Cretaceous. For comparison, dated offshore hydrocarbon secondary migration potentially coincides with our results. Back-stripping of time-constrained fracture sets is therefore a powerful method to investigate and quantify the dynamic evolution of petrophysical properties through geological time.
Coastal wetland resilience through local, regional and global conservation
Coastal wetlands, including tidal marshes, mangrove forests and tidal flats, support the livelihoods of millions of people. Understanding the resilience of coastal wetlands to the increasing number and intensity of anthropogenic threats (such as habitat conversion, pollution, fishing and climate change) can inform what conservation actions will be effective. In this Review, we synthesize anthropogenic threats to coastal wetlands and their resilience through the lens of scale. Over decades and centuries, anthropogenic threats have unfolded across local, regional and global scales, reducing both the extent and quality of coastal wetlands. The resilience of existing coastal wetlands is driven by their quality, which is modulated by both physical conditions (such as sediment supply) and ecological conditions (such as species interactions operating from local through to global scales). Protection and restoration efforts, however, are often localized and focus on the extent of coastal wetlands. The future of coastal wetlands will depend on an improved understanding of their resilience, and on society’s actions to enhance both their extent and quality across different scales.
Maternal effects in the model system Daphnia: the ecological past meets the epigenetic future
Maternal effects have been shown to play influential roles in many evolutionary and ecological processes. However, understanding how environmental stimuli induce within-generation responses that transverse across generations remains elusive, particularly when attempting to segregate confounding effects from offspring genotypes. This review synthesizes literature regarding resource- and predation-driven maternal effects in the model system Daphnia, detailing how the maternal generation responds to the environmental stimuli and the maternal effects seen in the offspring generation(s). Our goal is to demonstrate the value of Daphnia as a model system by showing how general principles of maternal effects emerge from studies on this system. By integrating the results across different types of biotic drivers of maternal effects, we identified broadly applicable shared characteristics: 1. Many, but not all, maternal effects involve offspring size, influencing resistance to starvation, infection, predation, and toxins. 2. Maternal effects manifest more strongly when the offspring’s environment is poor. 3. Strong within-generation responses are typically associated with strong across-generation responses. 4. The timing of the maternal stress matters and can raise or lower the magnitude of the effect on the offspring’s phenotype. 5. Embryonic exposure effects could be mistaken for maternal effects. We outline questions to prioritize for future research and discuss the possibilities for integration of ecologically relevant studies of maternal effects in natural populations with the molecular mechanisms that make them possible, specifically by addressing genetic variation and incorporating information on epigenetics. These small crustaceans can unravel how and why non-genetic information gets passed to future generations.
Pathogens and planetary change
Emerging infectious diseases, biodiversity loss, and anthropogenic environmental change are interconnected crises with massive social and ecological costs. In this Review, we discuss how pathogens and parasites are responding to global change, and the implications for pandemic prevention and biodiversity conservation. Ecological and evolutionary principles help to explain why both pandemics and wildlife die-offs are becoming more common; why land-use change and biodiversity loss are often followed by an increase in zoonotic and vector-borne diseases; and why some species, such as bats, host so many emerging pathogens. To prevent the next pandemic, scientists should focus on monitoring and limiting the spread of a handful of high-risk viruses, especially at key interfaces such as farms and live-animal markets. But to address the much broader set of infectious disease risks associated with the Anthropocene, decision-makers will need to develop comprehensive strategies that include pathogen surveillance across species and ecosystems; conservation-based interventions to reduce human–animal contact and protect wildlife health; health system strengthening; and global improvements in epidemic preparedness and response. Scientists can contribute to these efforts by filling global gaps in disease data, and by expanding the evidence base for disease–driver relationships and ecological interventions.
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