Ecology Letters

Detmer, A. Raine; Miller, Scott D.; Dubel, Alexandra K.; Ring, Kacie; John, Christian; Briggs, Cheryl J.; Rassweiler, Andrew; Moeller, Holly V.

doi: 10.1111/ele.70098pmid: 40094189

Spatial processes, particularly scale‐dependent feedbacks, may play important and underappreciated roles in the dynamics of bistable ecosystems. For example, self‐organised spatial patterns can allow for stable coexistence of alternative states outside regions of bistability, a phenomenon known as a Busse balloon. We used partial differential equations to explore the potential for such dynamics in coral reefs, focusing on how herbivore behaviour and mobility affect the stability of coral‐ and macroalgal‐dominated states. Herbivore attraction to coral resulted in a Busse balloon that enhanced macroalgal resilience, with patterns persisting in regions of parameter space where nonspatial models predict uniform coral dominance. Thus, our work suggests herbivore association with coral (e.g., for shelter) can prevent reefs from reaching a fully coral‐dominated state. More broadly, this study illustrates how consumer space use can prevent ecosystems from undergoing wholesale state transitions, highlighting the importance of explicitly accounting for space when studying bistable systems.

Londoño‐Nieto, Claudia; Butler‐Margalef, Michael; García‐Roa, Roberto; Carazo, Pau

doi: 10.1111/ele.70102pmid: 40111011

Sexual selection often leads to sexual conflict via pre‐copulatory (harassment) and/or copulatory (traumatic insemination) male harm to females, impacting population growth, adaptation and evolutionary rescue. Male harm mechanisms are diverse and taxonomically widespread, but we largely ignore what ecological factors modulate their diversification. Here, we conducted experimental evolution under low‐ (20°C ± 4°C), moderate‐ (24°C ± 4°C) and high‐temperature (28°C ± 4°C) regimes in Drosophila melanogaster, a species with male harm via harassment and seminal fluid proteins (SFPs), to show that temperature drives the divergent evolution of sexual conflict. At the low‐temperature regime, evolution resulted in reduced and less plastic harassment (i.e., pre‐copulatory harm) while at the high‐temperature regime, it was characterised by responses in the seminal proteome driven by differential expression of SFPs. Our results suggest that temperature can be key to understanding the past diversification and future (global warming) evolution of sexual conflict, and the maintenance of genetic variation in male harm traits.

Catano, Christopher P.; Bauer, Jonathan; Bassett, Tyler; Behrens, Eric; Brudvig, Lars A.

doi: 10.1111/ele.70095pmid: 40042156

Community ecology remains focused on interactions at small scales, which limits causal understanding of how regional and local processes interact to mediate biodiversity changes. We hypothesise that species pool size and immigration are two regional processes altering the balance between local niche selection and drift that cause variation in plant diversity. We manipulated the richness and number of seeds sown (species pool size and immigration respectively) into 12 grasslands across a landscape soil moisture gradient. Greater immigration and smaller species pools increased the variation in plant composition explained by soil moisture gradients but resulted in greater erosion of plant α‐diversity and spatial β‐diversity over time. Our results suggest that regional constraints on colonisation make community assembly more variable but help maintain species diversity by limiting biotic homogenisation. This study provides large‐scale experimental evidence on how regional contexts can alter the relative importance of fundamental processes shaping biodiversity change across scales.

Eisaguirre, Joseph M.; Lohman, Madeleine G.; Frye, Graham G.; Johnson, Heather E.; Riecke, Thomas V.; Williams, Perry J.

doi: 10.1111/ele.70092pmid: 40028932

Mortality risk for animals often varies spatially and can be linked to how animals use landscapes. While numerous studies collect telemetry data on animals, the focus is typically on the period when animals are alive, even though there is important information that could be gleaned about mortality risk. We introduce a thinned spatial point process (SPP) modelling framework that couples relative abundance and space use with a mortality process to formally treat the occurrence of mortality events across the landscape as a spatial process. We show how this model can be embedded in a hierarchical statistical framework and fit to telemetry data to make inferences about how spatial covariates drive both space use and mortality risk. We apply the method to two data sets to study the effects of roads and habitat on spatially explicit mortality risk: (1) VHF telemetry data collected for willow ptarmigan in Alaska, and (2) hourly GPS telemetry data collected for black bears in Colorado. These case studies demonstrate the applicability of this method for different species and data types, making it broadly useful in enabling inferences about the mechanisms influencing animal survival and spatial population processes while formally treating survival as a spatial process, especially as the development and implementation of joint analyses continue to progress.

Laforge, Michel P.; Vander Wal, Eric; Webber, Quinn M. R.; Geremia, Chris; Kauffman, Matthew J.; McWhirter, Douglas E.; Middleton, Arthur; Mong, Tony W.; Monteith, Kevin L.; Ortega, Anna C.; Sawyer, Hall; Merkle, Jerod A.

doi: 10.1111/ele.70101pmid: 40145127

Migratory herbivores often time spring migration to coincide with the green‐up of plants. When the timing of green‐up changes across years, herbivores can respond directly and be plastic to changing conditions or populations may adapt via inherent differences among individuals that may allow for an evolutionary response. We quantified plasticity and individual variation in the timing of spring migration and selection for high‐quality forage as a function of the timing of spring green‐up using behavioural reaction norms for three North American ungulate species. The timing of arrival to summer range (but not departure from winter range) was plastic to the timing of green‐up, and both arrival and departure timing were repeatable. Our results suggest that herbivores synchronise migration with the timing of green‐up by adjusting the pace of migration and may be buffered against change via individual differences. Quantifying plasticity and differences in responses represents a crucial step to elucidating the fate of species in a changing world.

Liang, Maowei; Cappelli, Seraina L.; Borer, Elizabeth T.; Tilman, David; Seabloom, Eric W.

doi: 10.1111/ele.70103pmid: 40110955

Biotic complexity, encompassing both competitive interactions within trophic levels and consumptive interactions among trophic levels, plays a fundamental role in maintaining ecosystem stability. While theory and experiments have established that plant diversity enhances ecosystem stability, the role of consumers in the diversity–stability relationships remains elusive. In a decade‐long grassland biodiversity experiment, we investigated how heterotrophic consumers (e.g., insects and fungi) interact with plant diversity to affect the temporal stability of plant community biomass. Plant diversity loss reduces community stability due to increased synchronisation among species but enhances the population‐level stability of the remaining plant species. Reducing trophic complexity via pesticide treatments does not directly affect either community‐ or population‐level stability but further amplifies plant species synchronisation. Our findings demonstrate that the loss of arthropod or fungal consumers can destabilise plant communities by exacerbating synchronisation, underscoring the crucial role of trophic complexity in maintaining ecological stability.

Mentesana, Lucia; Hau, Michaela; D'Amelio, Pietro B.; Adreani, Nicolas M.; Sánchez‐Tójar, Alfredo

doi: 10.1111/ele.70100pmid: 40102945

Egg‐laying species are key models for understanding the adaptive significance of maternal effects, with egg hormones proposed as an important underlying mechanism. However, even thirty years after their discovery, the evolutionary consequences of hormone‐mediated maternal effects remain unclear. Using evidence synthesis, we tested the extent to which increased prenatal maternal hormone deposition in eggs relates to fitness in wild birds (19 species, 438 effect sizes and 57 studies). Egg androgens, glucocorticoids, and thyroid hormones showed an overall near‐zero mean effect for both maternal and offspring fitness proxies. However, heterogeneity was high, suggesting that egg hormone effects on fitness are context‐dependent. Hormone type and age did not explain much of the observed variance, nor did methodological factors such as the type of study or experimental design. Heterogeneity decomposition showed that differences in effect sizes were mostly driven by within‐study variability and phylogenetic relationships. Our study provides the most comprehensive investigation to date of the relationship between egg hormones and fitness in vertebrates. By synthesising current knowledge, we aim to overcome theoretical shortcomings in the field of maternal effects via egg hormone deposition and inspire new research into its many intriguing aspects.

Fajgenblat, Maxime; Wijns, Robby; De Knijf, Geert; Stoks, Robby; Lemmens, Pieter; Herremans, Marc; Vanormelingen, Pieter; Neyens, Thomas; De Meester, Luc

doi: 10.1111/ele.70094pmid: 40084931

Online portals have facilitated collecting extensive biodiversity data by naturalists, offering unprecedented coverage and resolution in space and time. Despite being the most widely available class of biodiversity data, opportunistically collected records have remained largely inaccessible to community ecologists since the imperfect and highly heterogeneous detection process can severely bias inference. We present a novel statistical approach that leverages these datasets by embedding a spatiotemporal joint species distribution model within a flexible site‐occupancy framework. Our model addresses variable detection probabilities across visits and species by modelling phenological patterns and by extending the use of latent variables to characterise observer‐specific detection and reporting behaviour. We apply our model to an opportunistically collected dataset on lentic odonates, encompassing over 100,000 waterbody visits in Flanders (N‐Belgium), to show that the model provides insights into biological communities at high resolution, including phenology, interannual trends, environmental associations and spatiotemporal co‐distributional patterns in community composition.

doi: 10.1111/ele.14541pmid: N/A

Datta, Debit; Worthy, Samantha J.; Liu, Jun‐Yan; Zheng, Zheng; Cao, Min; Yang, Jie; Swenson, Nathan G.

doi: 10.1111/ele.70091pmid: 40084548

In tropical forests, trees often have damage in the form of visible cavities. However, the impacts of these cavities on tropical tree growth and survival are unknown, despite potential implications for the global carbon cycle. Here, we integrate 10 years of forest dynamics data with a survey of cavity presence on 25,450 rainforest trees (> 5 cm in diameter) in the 20 ha Xishuangbanna plot in southern China. We found that cavities negatively impacted tree growth, but not survival, with the growth of smaller trees more negatively affected by cavities. Variation in the impact of cavities was not explained by functional traits related to species life history strategy (specific leaf area, wood density, seed mass, leaf %N, leaf %P). These results suggest that cavities may affect both the compositional and carbon dynamics of tropical forests, but further research is needed to determine what drives variation amongst tree species in cavity impact.