3 ways drought alters aquatic disease

caryinstitute.org

Plagued by drought: how water scarcity reshapes host–parasite interactions

Droughts are intensifying worldwide, reorganizing ecosystems and threatening biodiversity and human health. Yet their effects on infectious diseases are poorly understood and sometimes paradoxical, with water limitation often amplifying water-associated infections. This complexity arises because drought not only reduces water availability but also restructures the host–pathogen interactions that govern transmission. Synthesizing theory and empirical evidence from water-associated diseases, we identify three ecological mechanisms through which drought modifies infection dynamics: concentrating organisms into shrinking refugia, selectively favoring drought-tolerant hosts, vectors, and pathogens, and amplifying transmission heterogeneity across landscapes. By linking hydrological change to core epidemiological and ecological processes, this framework highlights parasite traits and strategies likely to be favored during drought while providing a foundation for forecasting infections in a water-limited world.

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Climate reframes Darwin’s Naturalization Conundrum

Darwin’s Naturalization Conundrum asks whether invaders succeed by resembling or differing from native species. Ramirez-Parada et al. demonstrate that climate plays a crucial role in determining both outcomes: invaders resemble natives in cold or dry regions but diverge in warm, humid ones, thereby reframing the conundrum as an environmental continuum.

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Inbreeding tolerance predicts mechanisms of socially induced infertility in vertebrates

In cooperatively breeding species, reproductively capable individuals often forgo breeding to assist others. This socially induced infertility is typically viewed as a consequence of cooperative breeding, yet the remarkable diversity of its mechanisms remains unexplained. We propose that cooperative living inevitably increases opportunities for reproduction among relatives, selecting for reproductive suppression to regulate the costs of inbreeding and reproductive conflict. Species-specific variation in inbreeding tolerance subsequently determines how suppression evolves. Where inbreeding tolerance is high, increased intragroup reproductive conflict favours strong physiological suppression of the hypothalamic–pituitary–gonadal axis to maintain social cohesion. Where inbreeding tolerance is low, behavioural mechanisms regulate reproduction while preserving reproductive competence. This framework explains mechanistic diversity and generates testable predictions across cooperative vertebrates.

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Second thoughts about first principles in biology

In Box 1, the authors inadvertently misrepresented the work in one of the references. The sentence should state:

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The ripple effect of surface water on dryland ecosystems

Animals in dryland systems often aggregate around water, concentrating trophic pressure, transporting resources, and modifying habitat. These effects have been described as piospheres of degraded soils and vegetation; however, we argue that this framing is incomplete. We propose that animal aggregations around surface water generate a ripple effect: cross-scale, reciprocal impacts on both terrestrial and aquatic ecosystems that vary with water availability. As surface water becomes increasingly scarce under global change, management and conservation approaches should prioritize the restoration of spatiotemporal variability in surface waters. An integrated approach that bridges linked terrestrial and aquatic ecosystems and combines community and ecosystem ecology is necessary to identify emergent ecosystem properties, predict landscape-scale impacts of altered surface water availability, and inform adaptive management.

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The Cambrian fecal revolution: Fueling the Cambrian Radiation

Coprolites—fossil material extruded from an animal’s digestive system—represent a rare insight into trophic interactions in deep time. However, while the first animals appeared about 600 million years ago, the first coprolites are only observed in the earliest Cambrian. Conversely, in modern oceans, fecal pellets are an important part of the particulate organic carbon in the water column and the global flux of organic carbon to deep water. In this review, we analyze the impact of the advent of fecal matter on the Cambrian Radiation by examining coprolites, analyzing animal biology, and contextualizing this through the role of fecal pellets in the oceanic nutrient cycle. We illustrate the central position of coprolites in driving the Cambrian Radiation.

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Rethinking plasticity in fungal resilience and ecosystem functioning

Fungi are widely recognized as phenotypically plastic, a characteristic often invoked to explain the persistence of ecosystem functions under disturbance. How plasticity varies across taxa remains a key question. Emerging evidence implies species-specific, phylogenetically structured responses, with the strongest divergence under environmental extremes, making fungal community composition essential to ecosystem functioning.

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The overlooked role of epigenetics in fisheries-induced evolution

Fisheries-induced evolution (FIE) is typically framed in terms of genetic change, yet epigenetic processes linking environmental variation to phenotype remain overlooked. We propose that selective harvesting, by restructuring demographic and ecological conditions, can shape epigenetically mediated phenotypic responses in exploited populations, with important implications for FIE research and fisheries management.

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Redirecting

doi.org

Genomic metrics should inform formal conservation threat assessments

Whole-genome resequencing data, associated metrics, and their trends over time can be used to inform extinction threat rankings rendered by conservation agencies around the world. Surveys of individual genome sequences can critically address risks to population sustainability by means of key metrics such as heterozygosity. Genomic metrics have yet-unrealized potential to help authorities determine how a given population or species of conservation concern should be formally categorized (e.g., ‘listed’ or ‘delisted’) with respect to discrete threat categories. To stimulate productive discourse, we provide a general heuristic framework for how genomic metrics could be used to refine conservation threat assessments (e.g., to help determine whether species should be listed or not).

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Rare molecules as community architects

In natural chemical mixtures, a few molecules matter far more than their abundance suggests. Two recent studies identify defensive polyketides in estuarine mudflats and root exudate metabolites in a nitrogen-limited rhizosphere as compounds that restructure communities at trace concentrations, providing convergent evidence for candidate keystone molecules at the molecular scale.

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Species range contractions in geographic and environmental space

Species range contractions are a defining feature of the Anthropocene. Given their prevalence, a key question arises: do range contractions follow consistent patterns? Empirical studies have produced mixed results, revealing some emergent patterns, but also considerable variation among taxa. Here, we present a framework that seeks to explain this variation, conceptualising range contractions as the outcome of the interaction between species’ population growth rates and threat impacts, mediated by environmental conditions. Our framework shows how four primary patterns of range contraction arise, with a fifth emerging under incomplete threat spread. By describing when, where, and why particular patterns of decline occur, our framework advances understanding of species’ responses to global change and provides a basis for more generalisable conservation strategies.

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buff.ly

Pre-emptive behaviour in a landscape of intergroup conflict

Intergroup conflict is a powerful selective force throughout the animal kingdom. While research has traditionally focused on actions during and after contests, animals also exhibit behavioural flexibility in anticipation of potential intergroup encounters. Synthesising findings from diverse taxa, we describe how social species adjust pre-emptive information gathering, resource use, cohesion, synchrony, and intragroup interactions across a heterogeneous ‘landscape of intergroup conflict’. We show how variation in threat level, driven by spatial context, rival characteristics, and individual motivation, affects these behaviours, and how balancing sensed information and memories of past interactions underlies associated decision-making. Testing the consequences of intergroup pre-emptive behaviour using experimental, technological, and analytical advances will develop understanding of its role in socio-cognitive evolution, population dynamics, and community structure.

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Risks of heightened human–wildlife conflict when subsidies disappear

Anthropogenic food subsidies often elevate wildlife populations. Reducing these subsidies may alter behavior more rapidly than population size, creating a transient period of heightened human–wildlife conflict. Recognizing these transitional dynamics can improve conflict mitigation and conservation outcomes while enhancing public safety for communities living alongside dangerous species.

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Transboundary protected areas for freshwater biodiversity

Recently, Li et al. [1] initiated an important discussion about the role of transboundary protected areas (TBPAs) in biodiversity conservation, nature’s contributions to people, and cultural values. Their study opened an opportunity to broaden the discussion on freshwater biodiversity. This is essential because, for a long time and across many regions of the world, freshwater ecosystems, which have high levels of biodiversity, have been neglected when creating protected areas [e.g., 2–4]. Paradoxically, freshwater biodiversity is extremely threatened [e.g., 5] and, therefore, needs to be targeted in conservation strategies such as TBPAs [4].

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Student Conference on Conservation Science - Welcome

SCCS helps young conservation scientists gain experience, learn new ideas and make contacts that will be valuable for their future careers.

sccs-cam.org

Rebuilding the species pool within a phylogenetic framework

The species pool is a fundamental concept with the potential to connect ecological and evolutionary processes in community ecology and biogeography. However, current definitions of the concept primarily focus on contemporary ecological processes, ignoring the historical and evolutionary processes that generated the species pool. We propose a phylogenetic framework that defines the species pool by inferring evolutionary connectivity between communities in a biogeographic region. Our framework is better suited to addressing questions regarding assembly processes occurring over long time periods, offering deeper evolutionary insights for community ecology and conservation biogeography.

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The carbon cost of forest fragmentation: Size matters

Forest conservation typically prioritizes total area, treating every hectare as interchangeable regardless of how the landscape is configured. Analyzing 17 million patches, Zou et al. reveal that per-area productivity rises superlinearly with patch size. Fragmentation can, therefore, erode carbon sequestration, exposing a hidden cost that challenges area-based conservation paradigms.

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Biogeographical costs and opportunities of thermal adaptation

What determines where species occur and where they do not? Brightly et al. showed that cold-origin lineages are less likely to form amphitropical distributions. This raises questions about the biogeographical costs and opportunities of adapting to a particular thermal environment, with implications for species persistence or extinction under climate change.

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Microbial contributions to host life history trade-offs

All organisms must allocate finite resources among growth, maintenance, and reproduction, generating trade-offs that constrain adaptation. Host-associated microbiomes are dynamic resource engines capable of generating and reallocating energy and resources for their hosts. In doing so, we argue they may recalibrate the trade-offs fundamental to host life history evolution.

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Can habitat modification in the native range promote invasion?

The anthropogenically induced adaptation to invade (AIAI) hypothesis posits that selection in human-modified habitats within native ranges can adapt populations to invade similarly altered environments elsewhere. Although widely invoked, empirical tests of this hypothesis remain limited because disentangling native-range adaptation from post-introduction evolution is challenging. Here, we clarify how anthropogenic disturbance creates repeatable selective regimes and demonstrate how targeted sampling, population genomics, and genotype–environment associations can disentangle native-range adaptation from post-introduction evolution. Incorporating genomic offset, genetic architecture, nongenetic changes, experiments, and temporal data further strengthens inference. These insights and approaches establish the AIAI hypothesis as a mechanism that explicitly links human disturbance with the evolutionary dynamics of invasive species, providing novel insights into the prediction and management of biological invasions.

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The host–microbiome dimension of ecological regime shifts

Rising climate and local pressures increase the risk of regime shifts, yet despite progress, thresholds remain difficult to identify early enough to take action. We argue that this shortfall reflects a host-centric view that largely omits host-associated microbiomes, which can shape resilience by modulating stress tolerance, aiding recovery, and stabilizing alternative states through inhibitory chemical interactions. We propose a research agenda that integrates host-associated microbiomes into regime-shift ecology by combining novel microbiome manipulations in laboratory and field settings with regime-shift mapping tools, while simultaneously developing microbiome-based early warning indicators. Reframing regime-shift theory through a host-associated microbiome lens can provide practical tools to anticipate collapse, improve monitoring, and inform timely interventions, thereby supporting more adaptive and robust conservation under accelerating global change.

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The emerging field of wild animal welfare science

The emerging interdisciplinary field of wild animal welfare science (WAWS) explicitly expands the study of welfare to animals in the wild. It has applied value in informing how to improve the welfare of wild animals, ensuring they can thrive as well as survive in the face of the challenges of the Anthropocene. It also has intellectual value by generating new knowledge and insights about the affective states of wildlife. We aim to help scientists and practitioners understand how WAWS can support their work. To facilitate engagement in the field, we articulate core principles and key characteristics, and explore opportunities and challenges. We encourage those with relevant interests to engage in the field’s development and application.

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Integrating nutritional mutualists into the evolution of defense

Historically, mutualisms have been categorized by their benefits: nutrition, defense, or transportation. However, many nutritional mutualists have secondary effects on defense. In this review, we propose that nutritional mutualists are major, overlooked drivers of defense evolution and identify four distinct mechanisms by which they can affect the evolution of defense traits. Direct tests of all four mechanisms are scarce. We argue that this is because most work has focused on mutualist effects on trait expression rather than on the parameters that govern evolution: genetic variances, genetic correlations, and natural selection. We highlight new questions that this perspective brings into focus and outline experiments to test them. Finally, we propose that overlap in mutualism and defense resource budgets can unite mutualism and defense theory.

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