Characterization of biogeochemical cycles in agricultural watersheds: Integrating regional modelling assessment with downstream water quality.

Agriculture intensification represents an essential strategy to ensure food security for the growing human population, but it also poses considerable environmental concerns. Climate change and associated projections of an increased frequency of extreme precipitation and runoff events may amplify nutrient dynamics along the watershed-lake continuum, and could further exacerbate the poor water quality conditions downstream. Identifying hotspot locations with higher propensity for sediment and nutrient export and designing effective mitigation measures at the source is more critical than ever.

Listening Deeply to Indigenous People: A Collaborative Perspective and Reflection Between a Mapuche Machi and Ecologists.

Indigenous Peoples are key knowledge holders and essential partners to confront global environmental crises, especially biodiversity loss. Many calls have been made to better integrate Indigenous Traditional Ecological Knowledge and Western ecological sciences. However, partnerships between these communities are complex due to power imbalances, distrust, different objectives, and injustices towards Indigenous Peoples.

Correction: Genome size influences plant growth and biodiversity responses to nutrient fertilization in diverse grassland communities.

[This corrects the article DOI: 10.1371/journal.pbio.

Striking a balance between food security and water quality: A modelling analysis of agricultural management practices in mitigating non-point source phosphorus pollution.

Agriculture is necessary for food security and will likely further intensify to sustain the projected global human population growth. Strategies mitigating the impact of agricultural activity on the quality of freshwater resources are consequently needed more urgently than ever. The present study uses the Soil and Water Assessment Tool (SWAT) in two predominantly agricultural watersheds in southern Ontario, Canada to evaluate the efficiency of three stacked best management practices (BMPs) on no-tillage systems: crop rotations with winter cover crops, 20% reduction in fertilizers, and implementation of filter strips.

Genome size influences plant growth and biodiversity responses to nutrient fertilization in diverse grassland communities.

Experiments comparing diploids with polyploids and in single grassland sites show that nitrogen and/or phosphorus availability influences plant growth and community composition dependent on genome size; specifically, plants with larger genomes grow faster under nutrient enrichments relative to those with smaller genomes. However, it is unknown if these effects are specific to particular site localities with speciifc plant assemblages, climates, and historical contingencies. To determine the generality of genome size-dependent growth responses to nitrogen and phosphorus fertilization, we combined genome size and species abundance data from 27 coordinated grassland nutrient addition experiments in the Nutrient Network that occur in the Northern Hemisphere across a range of climates and grassland communities.

When indices disagree: facing conceptual and practical challenges.

Hypothesis testing requires meaningful ways to quantify biological phenomena and account for alternative mechanisms that could explain the same pattern. Researchers combine experiments, statistics, and indices to account for these confounding mechanisms. Key concepts in ecology and evolution, such as niche breadth (NB) or fitness, can be represented by several indices, which often provide uncorrelated estimates.

Linking changes in species composition and biomass in a globally distributed grassland experiment.

Global change drivers, such as anthropogenic nutrient inputs, are increasing globally. Nutrient deposition simultaneously alters plant biodiversity, species composition and ecosystem processes like aboveground biomass production. These changes are underpinned by species extinction, colonisation and shifting relative abundance.

Evolutionary history of grazing and resources determine herbivore exclusion effects on plant diversity.

Ecological models predict that the effects of mammalian herbivore exclusion on plant diversity depend on resource availability and plant exposure to ungulate grazing over evolutionary time. Using an experiment replicated in 57 grasslands on six continents, with contrasting evolutionary history of grazing, we tested how resources (mean annual precipitation and soil nutrients) determine herbivore exclusion effects on plant diversity, richness and evenness. Here we show that at sites with a long history of ungulate grazing, herbivore exclusion reduced plant diversity by reducing both richness and evenness and the responses of richness and diversity to herbivore exclusion decreased with mean annual precipitation.

Opposing community assembly patterns for dominant and nondominant plant species in herbaceous ecosystems globally.

Biotic and abiotic factors interact with dominant plants-the locally most frequent or with the largest coverage-and nondominant plants differently, partially because dominant plants modify the environment where nondominant plants grow. For instance, if dominant plants compete strongly, they will deplete most resources, forcing nondominant plants into a narrower niche space. Conversely, if dominant plants are constrained by the environment, they might not exhaust available resources but instead may ameliorate environmental stressors that usually limit nondominants.

Resolving the SLOSS dilemma for biodiversity conservation: a research agenda.

The legacy of the 'SL > SS principle', that a single or a few large habitat patches (SL) conserve more species than several small patches (SS), is evident in decisions to protect large patches while down-weighting small ones. However, empirical support for this principle is lacking, and most studies find either no difference or the opposite pattern (SS > SL). To resolve this dilemma, we propose a research agenda by asking, 'are there consistent, empirically demonstrated conditions leading to SL > SS?' We first review and summarize 'single large or several small' (SLOSS) theory and predictions.

Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide.

Anthropogenic nutrient enrichment is driving global biodiversity decline and modifying ecosystem functions. Theory suggests that plant functional types that fix atmospheric nitrogen have a competitive advantage in nitrogen-poor soils, but lose this advantage with increasing nitrogen supply. By contrast, the addition of phosphorus, potassium, and other nutrients may benefit such species in low-nutrient environments by enhancing their nitrogen-fixing capacity.

Author Correction: Leaf nutrients, not specific leaf area, are consistent indicators of elevated nutrient inputs.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Experimental dominant plant removal results in contrasting assembly for dominant and non-dominant plants.

Understanding why communities appear deterministically dominated by relatively few species is an age-old debate in ecology. We hypothesised that the dominant and non-dominant species in a community are governed by different assembly mechanisms where environmental conditions influence dominant species more than non-dominant species. Further, dominant plants moderate the environment where non-dominant species thrive, diminishing the influence of environmental filtering and increasing the influence of limiting similarity for non-dominant species.

Leaf nutrients, not specific leaf area, are consistent indicators of elevated nutrient inputs.

Leaf traits are frequently measured in ecology to provide a 'common currency' for predicting how anthropogenic pressures impact ecosystem function. Here, we test whether leaf traits consistently respond to experimental treatments across 27 globally distributed grassland sites across 4 continents. We find that specific leaf area (leaf area per unit mass)-a commonly measured morphological trait inferring shifts between plant growth strategies-did not respond to up to four years of soil nutrient additions.

Diverging responses of tropical Andean biomes under future climate conditions.

Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation.