Ecology最新文献

Hibernation is an important strategy used by many endotherms to conserve energy and water. Global warming is changing species' phenology and hibernation patterns, but whether such changes are beneficial or harmful depends on the species' life history traits, physiology, morphology, and behavior. Mechanistic niche models can be used to make strong inferences on such responses by explicitly quantifying the consequences of changed hibernation patterns for energy and water requirements. However, they have yet to be adapted to heterothermic species. Here, we address this problem by extending the endotherm biophysical model of the NicheMapR package to encompass torpor. This model accurately predicts the energy requirements of hibernating mammals over a broad size range from microbats to bears. We then used this approach to assess the effect of climate change on a Critically Endangered hibernator, the Australian mountain pygmy possum (Burramys parvus). Specifically, we contrasted conditions for the year 2010 with two future climate-change scenarios (2or 4°C of average warming) to identify: (i) the projected changes in energy and water requirements; (ii) the advantage conferred by hibernating for the species' energy and water requirements; and (iii) the areas across southeastern Australia that could continue to support hibernation. We projected an 11%–43% reduction in hibernation hours for the mountain pygmy possum under our two climate-change scenarios. In consequence, requirements for energy increased by 4%–21%, and for water by 10%–34%. Under current conditions, hibernation reduces annual energy requirements by 44%–52% and annual water requirements by 32%–42%, but in our projections, this energetic and hydric benefit of hibernation will decline due to climate change. The total area where hibernating and not hibernating is energetically equivalent is projected to increase by 60% under 4°C warming, preventing recovery from the species' severely restricted distribution at present. Our results show that climate change will have a profound impact on the duration and patterns of hibernation, a key survival strategy, for Burramys. Our framework for analyzing changing hibernation patterns provides a new and general way to test the vulnerability and plasticity of hibernating endotherms under global change.

Global biodiversity loss is threatening ecosystem functioning and human well-being. Arthropods above the ground have substantially decreased in abundance and diversity during the last 15–20 years. However, changes in belowground biodiversity, particularly in forests, received little attention. Here, we analyzed a comprehensive dataset of soil-living meso- and macrofauna in forests differing in land-use intensity within the framework of the open research platform “Biodiversity Exploratories” in Germany. The abundance of soil animal species was analyzed at 3-year intervals, covering 12 years from 2008 to 2020. Neither species richness nor γ-diversity of both soil meso- and macrofauna declined, suggesting contrasting dynamics of biodiversity above and below the ground. The density and diversity of soil mesofauna varied significantly between years within regions. These variations were closely related to the precipitation levels in the previous winter and during the sampling period. However, there was no consistent long-term downward trend, as declines in some years were offset by full recoveries. Temporal trends of soil macrofauna taxa densities were inconsistent and depended on regions and forest management intensity. The stability of many soil taxa was related to effective diversity and asynchrony of species fluctuations, supporting the portfolio effect. However, variance ratios not different from null communities and a negative impact of temporal species turnover on stability suggest a minor influence of compensatory dynamics as predicted by the insurance hypothesis. Instead, strong abiotic control resulted in synchronous species dynamics. Species densities, particularly those of soil mesofauna, depended heavily on abiotic conditions, such as soil moisture. While influencing the density and richness of soil fauna and modulating the effects of precipitation, forest management did not directly affect the stability of soil fauna communities. While our findings demonstrate a remarkable resilience of soil animal communities in temperate German forests amidst ongoing biodiversity decline, they are based on a limited temporal window and forests in central Europe. As such, caution is needed when extrapolating these results to longer timescales or wider spatial scales. Nonetheless, our study provides valuable insights into the temporal dynamics of soil faunal density and diversity, and the key drivers underlying their community stability.

Darwin's theory of natural selection provides two seemingly contradictory hypotheses for explaining the success of biological invasions: (1) the pre-adaptation hypothesis posits that introduced species that are closely related to native species will be more likely to succeed due to shared advantageous characteristics; (2) the limiting similarity hypothesis posits that invaders that are more similar to resident species will be less likely to succeed due to competitive exclusion. Previous studies assessing this conundrum show mixed results, possibly stemming from inconsistent study spatial scales and failure to integrate both functional and phylogenetic information. Here, we address these limitations using a 33-year grassland successional survey at Cedar Creek Ecosystem Science Reserve (USA). We incorporate functional dissimilarities, phylogenetic distances, environmental covariates, and species origin data for 303 vascular plant taxa (256 native, 47 introduced), collected from 2700 plots. In contrast with other studies, we test both hypotheses at two fine spatial scales—neighborhood (0.5 m²) and site (~40 m²)—to better capture competition and environmental filtering, respectively. Findings related to Darwin's naturalization conundrum depended on spatial scale and dissimilarity metric. Our results agreed with the pre-adaptation hypothesis at site scale (40 m²)—a much finer resolution than typically used to test the pre-adaptation hypothesis—highlighting the role of environmental filtering. At the neighborhood scale (0.5 m²), support for the limiting similarity hypothesis emerged when using functional dissimilarity, while phylogenetic distance aligned with the pre-adaptation hypothesis, demonstrating that different dissimilarity metrics can yield contrasting conclusions. In addition, native and introduced species showed different abundance patterns in relation to functional ranked dissimilarities, with introduced species reaching higher cover when they were taller than co-occurring species, had higher leaf dry matter content (LDMC) and lower seed mass. Introduced species also reached high cover with higher soil N concentrations and a shorter time after colonization, relative to native species. Our results suggest that inconsistent findings related to Darwin's naturalization conundrum may arise from an overreliance on single dissimilarity metrics and the use of spatial scales failing to capture underlying ecological processes. This highlights the need for more nuanced methodologies when testing the pre-adaptation and limiting similarity hypotheses.

GloNAF is a continuously updated, curated compilation of alien naturalized vascular plant inventories for geographic regions worldwide. Building on its predecessor, GloNAF 2.0 now contains 16,429 taxa and introduces major updates, including the standardization of taxonomic names using the World Checklist of Vascular Plants (WCVP), removal of outdated records, and the net addition of 117,229 new records. These new entries have substantially increased the size of GloNAF, resulting in a 26% increase in the number of naturalized taxa in the database and a 31% increase in the number of geographic regions compared to GloNAF 1.2. We provide an overview of GloNAF 2.0, highlighting its expanded geographic and taxonomic coverage. In addition, we have aligned GloNAF with FAIR data principles through improvements in data accessibility, metadata standards, and support for data reuse. GloNAF 2.0 represents a significant and comprehensive resource for researchers aiming to advance our understanding of the drivers and consequences of biological invasions and naturalization success. The dataset is published under a CC-BY 4.0 license; thus, when using these data, please give credit to this paper.

Insect biodiversity is under threat from multiple stressors, including climate change and extreme weather. For butterflies, nectar resource use is an understudied trait in relation to population trajectories and responses to global change. Here, we characterize nectar breadth for 50 species of montane butterflies occurring in the Sierra Nevada mountains of California and Nevada. These species displayed a wide spectrum of nectar use, including relative specialists and extreme generalists. Further, we examined how nectar breadth and other species traits, including latent variables indicating ecological flexibility and dispersal potential, were indicative of long-term population trajectories and responses to an extreme drought event from 2011 to 2015. Species that were more nectar-generalized were more likely to be declining, but nectar breadth did not predict how a species responded to extreme drought. Greater ecological flexibility, as reflected in other traits, was positively associated with population performance, while dispersal potential was negatively associated with population trajectories. Drought response was strongly associated with flight period, where species that fly later in the season are more susceptible to the negative effects of drought. Our study highlights the importance of considering butterfly nectar breadth in predicting population resilience and challenges assumptions about dietary generalism as a buffer against environmental change.

The dynamic balance between primary production and herbivory is key to the resilience of plant-dominated ecosystems across the world. However, many vegetated ecosystems are becoming increasingly susceptible to herbivore-triggered collapses, as this balance is disrupted due to predator declines, increasing nutrients, and other interacting impacts of global change. Yet without accessible, cost-effective tools to evaluate the production-consumption relationship, it is difficult to know how close an ecosystem is to imminent overgrazing collapse. Here, we explore the effectiveness of individually formed sea urchin grazing halos as robust indicators of marine habitat vulnerability to overgrazing. Halos are grazed patches of bare rock on macrophyte-dominated substrates that represent the balance between macrophyte production and per capita herbivore consumption. We measured 1211 halos in 31 locations across the Mediterranean Sea to characterize how plant-herbivore interactions are mediated by endogenous (i.e., species identity, habitat type, and sea urchin size) and exogenous factors (i.e., environmental factors influencing biotic and abiotic contexts: depth, nutrients, temperature, or protection level). Our results show that halo size was effective in detecting differences in the effect of endogenous and exogenous factors on these interactions. Across locations, halo size was sensitive to differences in (i) species identity, with some species being more impactful than others; (ii) the type of habitat, with some habitats being more vulnerable than others; (iii) protection level, with halo size consistently lower inside marine protected areas; (iv) urchin size, with halo size increasing consistently with herbivore size; (v) nutrient conditions, with halo size increasing as nutrient availability decreased; as well as (vi) depth, with halo size increasing consistently with depth. These results indicate that overgrazing vulnerability is highly contingent on local ecological contexts, which strongly mediate plant-herbivore interactions. While drivers of ecosystem collapse may be global, the ability of ecosystems to cope is often inherently local. We need locally responsive measures and contextually meaningful solutions to manage ecological integrity in the face of global change. In this context, individually measured grazing halos can be a powerful tool in assessing and managing the resilience of macrophyte ecosystems.

Disturbance is fundamental to ecosystem dynamics, and its management is foundational to effective ecosystem management for the conservation of biodiversity. Fire is a key agent of disturbance influencing faunal communities in many terrestrial ecosystems, and it underpins the conservation management of fire-prone ecosystems. However, we have a limited understanding of how faunal communities in fire-prone ecosystems respond to variation in fire frequency. Here, we use a long-term fire experiment to investigate the effect of fire frequency on lizard assemblages in an Australian tropical savanna. We sampled lizards using pitfall traps, funnel traps, and direct searches in replicate (n = 3) 1-ha plots that had been burnt every 1, 3, or 5 years or left unburnt for 18 years. We found no significant variation in total lizard abundance or the collective abundances of mesic, semiarid, or widespread biogeographic groups. The abundance of only one of the five most common species was significantly related to fire frequency. Species richness decreased with increased fire frequency and showed a humped relationship with woody cover. Species composition was slightly better explained by variation in woody cover than by fire frequency, with both effects relatively weak. Although woody cover declined with increasing fire frequency, it varied markedly both within and among plots experiencing the same fire treatment, which explains why fire frequency was not as strong a predictor of variation in lizard assemblages as woody cover. Our findings show that the diverse lizard assemblage in our tropical savanna system exhibits a very limited response to variation in long-term fire frequency and attribute this to the marked small-scale variation in woody cover that was inherent under any fire treatment. We conclude that small-scale patchiness in vegetation cover plays a critical role in the responses to fire of faunal species with relatively small foraging territories, reducing a need for larger scale fire mosaics under a “pyrodiversity begets biodiversity” paradigm.

Climate warming can destabilize ecological communities by altering species interactions. Population outbreaks, defined as rapid, exponential increases in population size within a given spatiotemporal scale, are naturally occurring phenomena with significant ecosystem-wide consequences. Such outbreaks are expected to increase in frequency under climate change, yet their ecological consequences under warming remain poorly understood. Here, we conducted a large-scale pond mesocosm experiment (48 mesocosms, each of 2500 L in volume) to show that warming significantly reduced the growth and impeded the regenerative capacity of aquatic plants following the outbreak of an aquatic moth (Parapoynx diminutalis). These effects were driven by warming magnifying herbivory, which substantially diminished the growth and recovery of macrophytes, leading to a turbid state dominated by phytoplankton. Our findings provide strong evidence that global warming can destabilize freshwater ecosystems under population outbreaks, risking the loss of basal resources that provide both food and habitat complexity. The cascading effects on the wider food web could lead to widespread loss of taxonomic and functional diversity, impairing essential ecosystem functions and services.