Global Change Biology最新文献

The negative impact of agricultural land on biodiversity is widely recognized. However, there remains a knowledge gap regarding the role of different crop types in maintaining biodiversity within the agricultural landscape. By extracting biodiversity data from global datasets and classifying different crop types, we quantified the contribution of different crop types to biodiversity. Our results indicate that biodiversity levels vary widely among crop types. We found a general loss of biodiversity when natural vegetation is converted to agricultural land, and highest losses in fiber crops, cereals and oil crops, and least in other crops (such as coffee or cocoa) and in mixed crops. In general, perennial crops retain more biodiversity than annual crops. Losses of biodiversity can be mitigated through mixed cropping of multiple crop types, especially by combining annual and perennial crops. The negative impact of converting natural vegetation to agriculture is greater in tropical than in nontropical areas, and hence, the import of commodities from these biodiversity-rich regions may be particularly detrimental. Given the ongoing increase in biodiversity losses from global intensification and expansion of agricultural land, maintaining or restoring natural vegetation, rating the crop-type-specific biodiversity, diversifying crops, and preferring perennial over annual crops, particularly in the tropics, need to be better considered and implemented in global agri-environmental schemes.

Nitrogen (N) transformation inhibitors have been widely recognized as a promising strategy to enhance crop productivity and mitigate N losses. However, the effectiveness of individual or combined inhibitors can vary significantly across different agroecosystems. Using meta-analysis and cost–benefit analysis (CBA), we synthesized findings from 41 peer-reviewed studies (285 observations) globally to evaluate the efficacy of urease inhibitors (UIs), nitrification inhibitors (NIs), and combined inhibitors (UINIs). We assessed their influence on soil inorganic N transformations, greenhouse gas emissions, and crop productivity across diverse climates, soil types, cropping systems, and fertilization practices. Our results indicated that combined UINIs were the most efficient, increasing crop yields by 5% and mitigating gaseous emissions by 51% compared to UIs or NIs alone. UINIs achieved these benefits by enhancing crop ammonium (NH₄⁺) availability through regulating urea hydrolysis and prolonging NH₄⁺ retention by suppressing nitrification in the soil. The CBA revealed that the overall economic benefits of UINIs application outweighed the costs, resulting in a net monetary benefit of $23.36 ha⁻¹, equivalent to a 6.4% increase in revenue. Both meta-regression and random forest analyses suggested that UINIs performance was strongly influenced by factors such as N application rate, organic matter content, and soil pH. Notably, more substantial responses were observed in fine-textured soils and/or crops exposed to high N fertilization rates. Acidic soils (pH < 6.5) exhibited the largest effect sizes, with increased crop productivity and reduced NH₃ volatilization due to specific inhibitory interactions. In conclusion, these findings highlight UINIs beneficial impacts on crop productivity and environmental conservation, achieving a “win-win” scenario by addressing various N-loss challenges while enhancing economic outcomes. Further exploration and optimization of the interaction between climate, soil, plant, and management systems and the use of appropriate inhibitors are crucial for maximizing their positive impact on global climate and reaping corresponding economic benefits.

Changes in temperature and precipitation are already influencing US forests and that will continue in the future even as we mitigate climate change. Using spatiotemporally matched data for mean annual temperature (MAT) and mean annual precipitation (MAP), we used simulated annealing to estimate critical thresholds for changes in the growth and survival of roughly 150 tree species (153 spp. for growth, 159 spp. for survival) across the conterminous United States (CONUS). We found that growth of nearly one-third of tree species assessed (44 spp.) decreased with any increase in MAT (42–49 species), whereas fewer responded negatively to projected regional trends in MAP (< 20 species each in the east and west). Hypothetical increases in temperature (+1°C, +2°C) increased average annual growth in the Central East and Pacific Northwest and decreased growth over large areas of the Rockies and Southeast, while decadal survival generally decreased with temperature. Average annual growth and decadal survival had unfavorable associations with projected precipitation, generally decreasing with wetter conditions (+25%) in the east and decreasing with drier conditions (−25%) in the west. Beyond these averages, there were species that positively and negatively responded nearly everywhere across the CONUS, suggesting changes in forest composition are underway. We identified only eight species out of ~150 assessed that were tolerant to increases in temperature, and 24 species in the east and seven in the west were tolerant to regionally specific trends in precipitation (increases in the east and decreases in the west). We assessed confidence on a 5-point scale (1–5) for five aspects of uncertainty. Average confidence scores were generally high, though some species and metrics had low confidence scores especially for survival. These findings have significant implications for the future national forest carbon sink and for conservation efforts in the face of climate change.

A comprehensive understanding of the formation of mineral-associated organic matter (MAOM) is a prerequisite for the sustainable management of soil carbon (C) and the development of effective long-term strategies for C sequestration in soils. Nevertheless, the precise manner by which microbial and mineral properties drive MAOM formation efficiency and its subsequent response to elevated temperature at the regional scale remains unclear. Here, we employed isotopically labelled laboratory incubations (at 15°C and 25°C) with soil samples from a ~3000 km transect across the Tibetan Plateau to elucidate the mechanisms underlying MAOM formation and its temperature response. The results indicated that both mineral protection and microbial properties were critical predictors of MAOM formation across the geographic gradient. The efficiency of MAOM formation was found to increase with the content of iron (Fe) oxides and their reactivity [i.e., the ratio of poorly crystalline Fe oxides to total Fe oxides (Fe_o:Fe_d)] but to decrease with the relative abundance of Gammaproteobacteria and Actinobacteria across the plateau. Moreover, a notable decline in MAOM formation efficiency was observed under elevated temperatures, which was concomitant with a reduction in the content and reactivity of Fe oxides, as well as the microbial assimilation of the labelled substrate. The attenuation of mineral–organic associations was identified as the primary factor contributing to the warming-induced reduction in MAOM formation. These findings highlight the necessity of incorporating organo–mineral associations and microbial properties into Earth System Models to accurately project soil C dynamics under changing climate.

Anthropogenic rapid warming has caused decreases in richness and body mass of birds following the metabolic theory of ecology; yet, the pervasiveness of these shifts remains controversial among different taxa. Here, by combining phylogenetic methods and fossil data, we synthesized spatial patterns of richness and body mass for 328 seabird species belonging to two groups: Procellariimorphae (PM) and non-Procellariimorphae (NPM). We found that the relationship between body mass and richness, as well as diversification rate, exhibits distinct patterns in these two groups. Ancestral state reconstruction analyses indicate that smaller PM, as opposed to NPM seabirds, evolved in warmer waters from larger ancestors and exhibited a slower diversification rate. Different ancestral climatic origins explain the reduced influence of environmental factors on richness patterns among PM compared to NPM seabirds. Furthermore, whereas NPM seabirds in high latitudes face a high extinction risk, warmer sea temperatures positively correlate with a high extinction risk among PM seabirds. Our results indicate that PM seabirds, evolving from cold waters, have reduced body mass and diversification rate, making them more vulnerable to warmer temperature.