Ecology最新文献

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including the standardization of taxonomic names using the World Checklist of Vascular Plants (WCVP), removal of outdated records, and the net addition of 117,229 new records.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.

Plant invasions may alter disease vector abundance by several mechanistic pathways, including modifying microclimates that influence vector survival or changing habitats to influence host use. Here, we used a field experiment and observational data to evaluate multiple mechanistic pathways (tick survival and host abundance) by which plant invasions may alter vector-borne disease risk using the common disease vector lone star tick (Amblyomma americanum), its preeminent host white-tailed deer (Odocoileus virginianus), and the widespread invasive cogongrass (Imperata cylindrica) in the southeastern United States. In the field experiment, ticks survived over 50% longer in areas dominated by the invasive plant compared to those with only native plant species. Invaded areas had lower temperatures and higher relative humidity, yielding a lower vapor pressure deficit (VPD) that likely reduced tick desiccation. The observational study showed similar average tick abundance in native and invaded plant communities and no difference in wildlife host (white-tailed deer) activity between plant communities. However, there was a positive relationship between tick abundance and white-tailed deer activity, but only in native areas. Together, these results suggest that more favorable microclimate conditions resulting in greater tick longevity are the dominant driver of tick abundance in invaded areas, while tick abundance in native-dominated areas may be promoted, at least in part, by white-tailed deer activity. Our results demonstrate that plant invasions can affect multiple, potentially counteracting mechanistic pathways that contribute to tick exposure risk. The complexity of these relationships highlights the need for a better understanding of how invasive species and other global change drivers influence disease vectors and, ultimately, disease transmission.

Many insects damage leaves, a phenomenon that is foundational to their impacts on terrestrial ecosystems. Leaf traits, including chemistry, shape these interactions. In turn, leaf-surface (phylloplane) microbes can act directly or in concert with leaf chemistry to influence leaf choice, especially by insects whose reproductive success is tied to prolonged contact with leaf surfaces. Leafcutter bees (Megachile spp.) cut disks from leaves to line their nests, with leaves and their associated microbes forming the environment in which bees' offspring develop. We hypothesized that phylloplane microbial communities act in concert with leaf chemistry to mediate interactions between the leafcutter bee M. lippiae and the plants they cut. We surveyed phylloplane communities on rose (Rosa × hybrida, Rosaceae) leaflets that were cut versus not cut by wild M. lippiae. Microbial communities differed between cut and non-cut leaflets, with Aspergillus spp. overrepresented on cut leaflets, and Alternaria sp. and Bacillus sp. overrepresented on non-cut leaflets. Then, we inoculated rose leaves in the field to test the effect of these microbial taxa on cutting. When inoculated onto rose leaves, Alternaria and Bacillus had no effect on cutting, but Aspergillus resulted in twice as many cuts as on sham-inoculated leaves. To test whether Aspergillus could protect bee nests against pathogens, we grew Aspergillus with two pathogenic fungi: the generalist insect pathogen Beauveria bassiania and three strains of Ascosphaera that cause chalkbrood disease in bee larvae. Aspergillus did not inhibit the growth of Beauveria, but it markedly slowed the growth of Ascosphaera. To clarify whether these phylloplane microbes reflect differences in leaf chemistry or are instead independent cues that influence leaf cutting, we used liquid chromatography-mass spectroscopy to characterize the metabolome of cut and non-cut leaflets. Chemistry did not differ between cut and non-cut leaflets, nor did it vary as a function of microbial community composition. Our results suggest that Aspergillus, a common member of rose phylloplane communities, mediates interactions between leafcutter bees and roses, potentially affecting the fitness of both partners. This study reveals a previously unexplored role for phylloplane microbes in plant–insect associations.