Pollinator conservation paradox: Exotic wildflowers provision native pollinators under anthropogenic changes

Ecosphere · 2026-05-01

Abstract Invasive wildflowers pose a conservation paradox: While they often reduce the diversity and abundance of native wildflowers, they can provide resources for native pollinators, including imperiled species. Previous work has framed wildflower invasions as outcomes of global change, but less is known about how interacting anthropogenic drivers influence both invasion and pollination. In particular, it remains unclear whether exotic wildflowers compensate for native floral losses under ongoing environmental change. To address this, we tested whether exotic wildflowers provide resources for native pollinators under two drivers of wildflower decline: eutrophication and defaunation. Using a factorial global change experiment at three sites in the highly invaded California floristic region, we tested whether increases in exotic wildflowers (1) sustain pollinator visitation and richness, (2) maintain pollinator composition and function, and (3) facilitate co‐invasion by exotic pollinators. We found that eutrophication promoted exotic asters, which served as visually prominent, attractive hubs in plant–pollinator networks. These asters attracted both generalist and specialist native pollinators but also increased visitation by exotic pollinators, raising the risk of invasional meltdown. Our results suggest that exotic wildflowers can buffer pollinator communities against anthropogenic change but may do so while shifting pollinator composition toward non‐native species.

Scenarios and strategies for future‐proofing ecosystem management under climatic novelty

Conservation Biology · 2026-03-09

Climate change is driving unprecedented declines in dominant, habitat-forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning, is essential for designing effective forward-looking management strategies. We explored 3 scenarios that describe a range of ecosystem reassembly trajectories following declines in previously dominant habitat-forming taxa: compensation, in which functionally similar subdominant or immigrating taxa maintain ecosystem structure and function; decline, in which no compensation occurs leading to loss of ecosystem structure and function; and transformation, in which the ecosystem present historically can no longer persist and shifts into a fundamentally different ecosystem type with distinct structure and function. This range of potential outcomes highlights the urgent need to assess the ecological feasibility and functional implications of potential management actions. Scientists and managers can work together to quantify local-scale climatic novelty and ecosystem resilience to better predict the most likely reassembly trajectories and identify management interventions that will optimize ecosystem function. This approach would allow for more proactive planning to support persistence of ecosystem structure and function, helping to future-proof ecosystem management in a rapidly changing world.

Interactive effects of plant-mediated controls and substrate quality on fungal necromass decay

Plant and Soil · 2026-03-09

Insights on global rangeland ecosystem services shaped by grazing and fertilization

Frontiers in Ecology and the Environment · 2026-01-13 · 1 citations

Rangelands are crucial to human well‐being, but their ability to provide ecosystem services is threatened. We (1) quantified key ecosystem services provided by rangelands, (2) assessed short‐ and long‐term impacts of fertilization (nutrient addition) and the exclusion of large grazing herbivores with fences (herbivore exclusion) on services, and (3) identified synergies and trade‐offs among services. We measured indicators of ecosystem services and plant diversity at 79 sites across six continents in the global Nutrient Network. Short‐term herbivore exclusion increased forage quantity and soil fertility, but longer‐term herbivore exclusion decreased both along with plant richness and pollination. Nutrient addition improved forage provisioning, soil stability, climate regulation, and control of soil erosion but lowered plant diversity and impeded delivery of related services, especially after prolonged application. We found synergies between plant diversity and pollination, as well as between soil fertility, soil stability, and climate regulation. Trade‐offs between forage stability and quality persisted after nutrient addition but disappeared with herbivore exclusion. Our results suggest that alternative management actions may sustain livestock production while maintaining rangeland ecosystem services.

Data from: Community complexity modulates the predictive power of demographic metrics on plant species resilience to disturbances in a distributed grassland experiment

Open MIND · 2026-01-01

A subset of a larger data set collected by the distributed grassland network Disturbance and Recovery Across Grasslands Network (DRAGNet). Grassland plant species percentage cover values are collected at the plot level across 40 sites of the network. This data covers the first four years of the experiment: the first pre-treatment year, followed by 3 years of treatments. Treatments applied during the experiment and captured in this data set include physical disturbance and nutrient additions.

Intra-annual precipitation variability mutes or magnifies the impact of wet and dry years on plant biomass

bioRxiv (Cold Spring Harbor Laboratory) · 2026-02-06

Abstract As the atmosphere warms, both the amount and timing of precipitation are changing, but how those two trends interact to influence plant growth remains unresolved. Using 5-15 years of data from 48 globally distributed grassland sites, we quantified how the temporal distribution of precipitation within the year (evenness) interacts with annual precipitation amount and nutrient limitation to influence plant biomass. Annual precipitation anomalies had a large influence on plant biomass when intra-annual precipitation was more evenly distributed (frequent small events) and little impact when less even (infrequent large events). This relationship was consistent across aridity gradients and nutrient limitations and strongest in systems with warm wet seasons. Our work shows that the response of plant systems to changes in annual precipitation amount are largely dependent on how evenly it is temporally distributed.

Plant neighbours, not consumers, drive intraspecific phytochemical changes of two grassland species in a field experiment

AoB Plants · 2025-10-30 · 1 citations

Abstract Plants use chemicals to respond to their environments. Despite the impact of competition on plant productivity, few studies consider how plant–plant competition affects phytochemistry; most phytochemistry studies focus on plant–consumer interactions. It therefore remains unclear how plants chemically respond to changes in both competition and consumer pressure. We used 1H-NMR spectroscopy to characterize the phytochemistry (both primary and secondary metabolites) of a C4 grass (Andropogon gerardi) and a legume (Lespedeza capitata) in a field experiment. Both species were grown with intraspecific or interspecific neighbours (monoculture or 16-species polyculture) with or without a combined fungicide + insecticide treatment (consumers reduced vs. consumers present) in a factorial design. We measured species aboveground biomass, healthy plant cover (NDVI) and phytochemistry in the four treatments to determine whether plants alter their biomass, phytochemistry, or both in response to neighbours and herbivory. Phytochemistry of A. gerardi did not vary with neighbour identity or consumers, in contrast to A. gerardi biomass, which was higher under interspecific competition and when consumers were reduced. Phytochemistry of L. capitata was also unrelated to consumer reduction, though L. capitata had higher NDVI under reduced consumers. However, L. capitata had lower biomass and exhibited phytochemical signs of metabolic stress (lower sugars and higher amino acid production) when grown with interspecific neighbours. Theory and empirical work have focused on coevolution with consumers as driving phytochemical variation, but our results suggest that—at community scales—the competitive environment may be more important than consumer pressure in determining short-term phytochemical responses of some species.

Drought intensity and duration interact to magnify losses in primary productivity

Science · 2025-10-16 · 34 citations

As droughts become longer and more intense, impacts on terrestrial primary productivity are expected to increase progressively. Yet, some ecosystems appear to acclimate to multiyear drought, with constant or diminishing reductions in productivity as drought duration increases. We quantified the combined effects of drought duration and intensity on aboveground productivity in 74 grasslands and shrublands distributed globally. Ecosystem acclimation with multiyear drought was observed overall, except when droughts were extreme (i.e., ≤1-in-100-year likelihood of occurrence). Productivity losses after four consecutive years of extreme drought increased by ~2.5-fold compared with those of the first year. These results portend a foundational shift in ecosystem behavior if drought duration and intensity increase, from maintenance of reduced functioning over time to progressive and profound losses of productivity when droughts are extreme.

Chronic Nitrogen Additions Decrease Rates of N Recovery and Increase Rates of Soil Inorganic N Availability in A Temperate Grassland

Ecosystems · 2025-05-20 · 1 citations

Abstract Anthropogenic activities add more reactive nitrogen (N) to the environment than all natural sources combined, and the fate of this N is of environmental concern. If N that is deposited on terrestrial ecosystems through atmospheric deposition is retained in plant tissues or soil organic matter, it could stimulate carbon (C) storage in plant biomass or soils. However, added N also could increase soil inorganic N concentrations and leaching, potentially polluting watersheds, particularly in areas with low-N soils and/or a high propensity for leaching, such as sandy or arid areas. Here, we assessed N allocation and retention across a 13-year experimental N addition gradient in a temperate grassland. We found that N accumulation decreased significantly at mid- to high levels of N addition compared to the Control, such that ecosystem N pools were equivalent across a 10 g m −2 year −1 range of annual N addition rates (0–10 g N m −2 year −1 ), which spans most of the global range of N deposition. Nitrogen addition increased plant tissue percent N, but the total pool of N did not increase because of reduced plant biomass, particularly in roots. Nitrogen addition also increased soil inorganic N concentrations. Our results indicate that N addition is unlikely to increase grassland N pools, particularly in sandy or low-fertility ecosystems with a high potential for leaching because high application rates lead to N saturation, and additional inputs are lost.

Carbon availability, soil pH, and microbial allocation to nitrogen acquisition shape grassland heterotrophic respiration in response to a decade of nitrogen addition

Soil Biology and Biochemistry · 2025-10-04