Ecology最新文献

Spatial resource heterogeneity (SRH; the variable spatial distribution of resources) is a surprisingly understudied component of oscillatory predator–prey dynamics. SRH may be particularly important in large, ecologically realistic networks where different patterns of resource distribution can manifest, which have important implications for spatial synchrony. Here, we explore how SRH in large spatial networks influences both local and regional predator–prey stability. To do so, we employ a spatially explicit Rosenzweig–MacArthur model and vary resource distribution accordingly: homogeneously distributed resources of low, medium, and high productivity and heterogeneously distributed resources. The latter includes networks with SRH of random variability in productivity (“random networks”) or a spatial productivity gradient (“gradient networks”). We analyze the effects of local patch factors (i.e., productivity and connectivity) and regional factors (i.e., productivity distribution and structure) as components of SRH. First, we find that SRH, regardless of productivity distribution type, stabilizes regional dynamics via statistical stabilization of asynchronous oscillations and local dynamics by reducing the amplitude of oscillations and bounding them further from zero. Local stabilization, in particular, is enhanced in networks with SRH compared to those with homogeneously distributed resources. Second, the local-level stabilizing effect in networks with SRH increases with patch productivity and connectivity. Lower productivity patches are subsequently destabilized in return, albeit minimally. Lastly, random variability in productivity provides the greatest effects observed at the local level, because high-productivity patches are often highly connected to lower ones in a way not possible in gradient networks. We conclude that SRH is a particularly strong driver of predator–prey stability in that it provides local-level stability in a way that other forms of heterogeneity do not. To promote predator–prey stability in managed systems, stability in oscillatory predator–prey systems is likely to arise from (1) variable resource distribution patterns in large spatial networks and (2) high connectivity between patches of different productivity levels.

Apex consumers are declining worldwide. While the effects of apex predator declines on ecosystems are widely documented, the cascading effects of apex scavenger declines are poorly understood. We evaluated whether disease-induced declines of an apex scavenger, the Tasmanian devil (Sarcophilus harrisii), increased carrion use by invertebrate scavengers. We manipulated devil access to 36 carcasses across a gradient of devil density from east to west Tasmania and measured carcass use by invertebrates. We found the amount of carcass removed within 5 days was 3.58 times lower at sites with the lowest devil densities. Adult carrion beetle (Ptomaphila lacrymosa) and blow fly (Calliphoridae) larvae abundances were two times higher at open-access carcasses at low-density sites than at intermediate- and high-density sites. Adult beetles persisted for 10 days at the low-density site but declined after 5 days when devils had access to carcasses in intermediate- and high-density sites. Blow fly larvae abundance was not affected by devils in the low-density site but decreased with devil access in intermediate- and high-density sites. Our results suggest that apex scavenger declines may increase invertebrate scavenger abundance and their contribution to carrion decomposition, with potential cascading effects on nutrient cycling and ecosystems.

Trait-based ecology relies on high-quality, well-documented data to explore how plant traits relate to environmental conditions, community assembly, and ecosystem functioning. However, the reuse and synthesis of trait data across studies remain limited by several constraints: a lack of detailed metadata, heterogeneous protocols, absence of individual-level measurements, and underrepresentation of certain trait types—particularly below-ground traits. Many existing datasets also lack the environmental details necessary to investigate trait–environment relationships at local scales. Here, we present FAIRTraits, a comprehensive dataset that addresses these limitations by compiling 189,452 records of quantitative trait measurements collected between 1997 and 2023 from 1955 populations of 240 vascular plant species in the Northern Mediterranean Basin, a region known both for its exceptional biodiversity and as a climate change hotspot. All data were collected by a single research group using consistent and well-documented field and laboratory protocols, ensuring internal consistency across traits, species, sites, and years. FAIRTraits includes 180 traits measured at the individual or replicate level, with no aggregation. It features an unprecedented diversity of traits spanning all major plant organs—leaves, stems, roots, and reproductive parts. These include widely used traits such as specific leaf area and plant height, but also traits that are rarely reported, especially below-ground traits related to root morphology, as well as mechanical properties, phenology, and microbial associations. In addition to raw measurements, species are annotated with categorical descriptors (e.g., life form, photosynthetic pathway, and successional status), and species-level values taken from a Mediterranean flora, for key traits such as reproductive phenology and maximum height. To support analyses that account for environmental variability, each observation is linked to detailed descriptors of the plot where the individual was sampled, including climate data, soil physicochemical properties, and disturbance regime. Full metadata on sampling protocols and measurement methods are provided for every trait and environmental variable. FAIRTraits was built in compliance with the FAIR principles of data management (Findable, Accessible, Interoperable, and Reusable). Metadata are described using the Ecological Metadata Language (EML); trait definitions are standardized using community-endorsed semantic resources. The data are archived across two interoperable repositories: GBIF (via Darwin Core and trait-specific extensions) for taxon–trait associations and InDoRES for environmental and contextual data. These efforts ensure long-term preservation, data traceability, and seamless integration with plant trait databases such as BROT or TRY, and cross-organism initiatives such as the Open Traits Network or the Encyclopedia of Life. FAIRTraits offers a robust, richly document

Changing snow conditions due to climate warming may negatively affect the northern fauna that depend on it for their winter survival. To avoid cold temperatures, Arctic lemmings seek refuge in areas with deep snowpack where they build nests in which they can reproduce if conditions are favorable. The presence of a soft depth hoar layer ensures efficient digging and facilitates lemming movement in the snow, but such favorable conditions are highly dependent on weather conditions at the beginning of winter. Using a 17-year time series, we assessed the impact of snow conditions and specific weather events on lemming winter reproduction and population growth on Bylot Island in the Canadian High Arctic, a site characterized by a cold and dry Arctic climate. We focused on snow onset date, snow depth, and weather events leading to a hardening of the snow basal layer (i.e., rain-on-snow, melt-freeze, and freezing rain) at the beginning of winter. We also examined possible differences between two lemming species, the brown lemming (Lemmus trimucronatus) and the collared lemming (Dicrostonyx groenlandicus), the latter presenting unique morphological adaptations to snowy environments. We found that the intensity of winter reproduction of both species was negatively related to the intensity of rain-on-snow, melt-freeze, and freezing rain events. Winter population growth was also negatively related to the intensity of rain-on-snow and melt-freeze events in brown lemmings but not in collared lemmings. Contrary to our expectation, no relationship was found between lemming demography and snow onset date or snow depth. We found a higher reproductive rate in collared than in brown lemmings, suggesting a more effective strategy to save energy for winter reproduction in the former species. Overall, this study shows that even moderate weather events, in comparison with other Nordic sites, can impact lemming population growth in winter, likely by reducing their capacity to reproduce due to a hardening of the snowpack. The expected increase in such weather events with climate change may threaten lemming populations even in the High Arctic, as well as predators that depend upon them.

Mountain species are predicted to respond to warming temperatures by moving to higher elevations that remain relatively cool. Species can track warming by shifting their entire distributions upwards (the “escalator to extinction” hypothesis) or by increasing in abundance in the upper portion of their elevational range while maintaining stable elevational limits (the “upslope lean” hypothesis). Alternatively, mountain species may not change their abundance or distribution despite climate change (the “persist-in-place” hypothesis). Here we evaluate these three contrasting hypotheses by analyzing responses of breeding forest bird species to three decades of warming in southwestern British Columbia, Canada. Consistent with the upslope lean hypothesis, species' optimum elevations (elevations of highest abundance) increased by an average of 126 m, approximately tracking upslope movements in temperature isotherms. In contrast, species' elevational range limits were stable on average, contra the escalator to extinction hypothesis. Many individual species had stable distributions and abundances, and species with upslope abundance increases typically maintained stable abundances within the lower elevation portions of their range. Taken together, most species in our study region appear to be responding neutrally or favorably to warming temperatures. Nevertheless, one mountain species, the Canada Jay, Canada's national bird, is declining and vulnerable to the escalator to extinction within our study region. Overall, we emphasize the importance of empirical data—and abundance data in particular—when evaluating mountain species' vulnerability to climate change.

In plant communities, biomass varies considerably in both space and time. Both top down (e.g., pathogens) and bottom up (e.g., nutrients) can influence this variation, but their relative importance and the pathways in which they do so remain poorly understood. Here, we examined the separate and interactive influence of fungal pathogen exclusion and nitrogen addition on the spatial variability of plant community biomass and the underlying mechanisms in an alpine meadow. We found that fungal pathogen exclusion and nitrogen addition independently increased community spatial variability by increasing the variance of plant biomass more than the mean biomass, but there was no interaction between the treatments. Fungal pathogen exclusion increased spatial variation in community biomass by enhancing species covariation. In contrast, nitrogen addition increased community spatial variability mainly by enhancing species variability through increasing beta diversity among communities. Additionally, our observed increase in the spatial mean and variance of biomass in the pathogen exclusion treatment was mainly driven by dominant grasses, whereas all functional groups responded to nitrogen addition. Our results suggest that higher trophic groups and resources can regulate spatial variability of biomass distribution through distinct mechanisms. This enhances our knowledge regarding the roles of top-down and bottom-up forces in maintaining ecosystem functions across spatial scales.

Dryland productivity is highly sensitive to precipitation variability, and models predict that rainfall variability will increase in the future. Numerous studies have documented the relationship between productivity and precipitation, but most focus on aboveground production (ANPP), while the effects on belowground production (BNPP) remain poorly understood. Furthermore, previous research suggests that ANPP and BNPP are uncoupled within ecosystems, but the degree to which rainfall variability affects the interplay between aboveground and belowground production is unknown. We conducted a long-term rainfall manipulation experiment in Chihuahuan Desert grassland to investigate how the size and frequency of growing season rain events affected BNPP and its relationship to ANPP. Experimental plots received either 12 small-frequent rain events or 3 large-infrequent events during the monsoon season for a total of 60 mm of added rainfall per treatment per year. All plots, including three controls, received ambient rainfall throughout the year. Total BNPP ranged from a low of 94.7 ± 38.2 g m² year⁻¹ under ambient conditions to a high of 183.7 ± 44.6 g m² year⁻¹ under the small-frequent rainfall treatment. Total BNPP was highest under small-frequent rain events, and there was no difference in BNPP between 0–15 and 15–30 cm soil depths in either rainfall treatment. ANPP and BNPP were uncorrelated within rainfall treatments, but weakly positively correlated across all plots and years. Our results contribute to a growing body of research on the importance of small rain events in drylands and provide further evidence regarding the weak coupling between aboveground and belowground processes.

A fundamental goal in ecology is to understand the drivers of stability in natural ecosystems in the face of disturbances. However, this is challenging when biotic and abiotic stressors operate simultaneously across multiple spatial scales. Such is the case for bull kelp forests (Nereocystis luetkeana) in northern California, where losses of predators combined with marine heatwaves have led to shifts from kelp forest to sea urchin barren states. However, despite the >90% loss of bull kelp forests since 2014, some patches remain. Here, we investigate the bull kelp community assemblage in these remnant patches as well as the drivers of bull kelp forest resistance. We used a combination of in situ field surveys (years 2020–2022), remote sensing data (years 2016–2022), and a laboratory grazing experiment with urchins (Strongylocentrotus purpuratus). We found that, in addition to the two dominant states (kelp forest vs. urchin barren), there is a third community state dominated by understory canopy-forming macroalgae that stays subsurface. Moreover, bull kelp abundance and cover were positively associated with freshwater flow and proximity to freshwater sources, and bull kelp persistence was positively associated with sand cover, all of which seem to diminish sea urchin abundance and the negative effects of sea urchin herbivory on bull kelp. This was also shown in the laboratory experiment where sea urchin herbivory rates on bull kelp decreased with decreasing salinity. Overall, these results suggest that freshwater influence in shallow coastal environments could prevent loss of bull kelp and show that land–sea connections should be considered for species-specific management and conservation actions.