Tom Crowther

Last Name

Crowther

First Name

Tom

ORCID

0000-0001-5674-8913

Organisational unit

09625 - Crowther, Thomas Ward (ehemalig) / Crowther, Thomas Ward (former)

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Publications 1 - 10 of 32

A globally consistent negative effect of edge on aboveground forest biomass
Yang, Gayoung; Crowther, Tom; Lauber, Thomas; et al. (2025)
Nature Ecology & Evolution
Because of widespread forest fragmentation, 70% of the world’s forest area lies within 1 km of an edge. Forest biomass density near edges often differs markedly from biomass density in the interior. In some biomes, these ‘edge effects’ are responsible for substantial reductions in forest carbon storage. However, there is little consensus on the direction and magnitude of edge effects on forest biomass across the globe, which hampers their consideration in forest carbon stock accounting. Here we examined eight million forested locations to quantify variability in edge effects on biomass at a global scale. We found negative edge effects across 97% of examined areas, with aboveground biomass density on average 16% lower near edges than in interior forests. Higher temperature, precipitation and proportion of agricultural land were linked to more negative edge effects. Along with differences in the spatial scale of analysis, this variation can explain contrasting observations among previous studies. We estimate that edge effects have reduced the total aboveground biomass of forests by 9%, equivalent to a loss of 58 Pg. These findings underscore the substantial impact of forest fragmentation on global biomass stocks and highlight the critical need to account for edge effects in carbon stock assessments.
Fungal diversity as a key driver of soil multifunctionality along a European latitudinal gradient
Han , Xingguo; Doménech-Pascual , Anna; Donhauser , Jonathan; et al. (2025)
Geoderma
Soils harbor a vast diversity of microorganisms and play a crucial role in global carbon and nutrients cycles. Yet, the extent and drivers of variations in soil microbial diversity and functioning across environmental gradients at continental scales remain poorly understood. Here, we investigated the diversity and network complexity of prokaryotic and fungal communities and their relationships with soil multifunctionality (SMF) – an integrative index for C-, N- and P-cycling functions – along a 3,000-km latitudinal transect across Europe (37° to 62°N), spanning biomes from Mediterranean drylands, temperate to boreal forests. We found that SMF followed a hump-shaped latitudinal pattern, peaking at mid-latitude temperate forests and declining toward the southern Mediterranean drylands and northern boreal forests. Fungal alpha-diversity, together with mean annual precipitation (MAP), mean annual temperature (MAT), and soil pH and C/N ratio, were key contributors to SMF across latitudes, while prokaryotic alpha-diversity had little effect. Both prokaryotic and fungal communities were predominantly structured by dispersal limitation, land cover, climate and soil properties, with fungal communities more strongly limited by spatial dispersion. Our study highlights the significant role of fungal diversity in sustaining SMF along the European latitudinal gradient and demonstrates the importance of both large-scale climatic and biogeographical factors and local edaphic and land cover variables in shaping microbial diversity. Our findings offer valuable insights for the conservation of ecosystem functions.
Wilderness Quality, Habitat Connectivity, and the Effectiveness of Protected Areas Diminish as Human Activities Intensify
Tu, Wenna; Crowther, Tom; Du, Yunyan; et al. (2025)
Conservation Letters
Intact and connected wilderness areas are vital for biodiversity conservation. The Qinghai–Tibet Plateau (QTP) hosts some of the world's most unique ecosystems. Yet, increased economic development across the QTP raises concerns about the potential negative effects of increased human pressure on the stability of this unique biodiversity hotspot. In this study, we assessed the impacts of human activities on wilderness quality, habitat connectivity, and the effectiveness of protected areas across the QTP from 2000 to 2020. During this period, wilderness areas experienced a 41.08% reduction in large, intact patches, with a notable decline in quality, particularly in the eastern region of the QTP. Habitat connectivity decreased over time, and the cost of animal migration increased, with the most striking changes in areas with the highest initial wilderness quality. Economic growth and infrastructure development had strong negative impacts on the effectiveness of protected areas, with experimental protected areas declining faster than non-protected areas during periods of high infrastructure expansion. These emergent trend highlights the significant impact of increasing human pressure on animal migration and underscore the need for adaptive management and careful monitoring to ensure protected areas effectively prevent habitat fragmentation and support animal migration across global biodiversity hotspots.
Fragmentation increased in over half of global forests from 2000 to 2020
Zou, Yibiao; Crowther, Tom; Smith, Gabriel; et al. (2025)
Science
Habitat fragmentation, in which contiguous forests are broken into smaller, isolated patches, threatens biodiversity by disrupting species movement, shrinking populations, and altering ecosystem dynamics. Past assessments suggested declining global fragmentation, but they relied on structure-based metrics that overlook ecological connectivity. We analyzed global forest fragmentation from 2000 to 2020 using complementary metrics that captured patch connectivity, aggregation, and structure. Connectivity-based metrics revealed that 51 to 67% of forests globally—and 58 to 80% of tropical forests—became more fragmented, which is nearly twice the rate suggested by traditional structure-focused methods (30 to 35%). Aggregation-focused metrics confirmed increases in 57 to 83% of forests. Human activities such as agriculture and logging drive this change. Yet protected tropical areas saw up to an 82% reduction in fragmentation, underscoring the potential of targeted conservation.
The pace of life for forest trees
Bialic-Murphy, Lalasia; McElderry, Robert M.; Esquivel-Muelbert, Adriane; et al. (2024)
Science
Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world's forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.
Coarse woody debris accelerates the decomposition of deadwood inputs across temperate forest
Bradford, Mark A.; Veen, G.F. Ciska; Bradford, Ella M.; et al. (2023)
Biogeochemistry
Wood decomposition is regulated by multiple controls, including climate and wood traits, that vary at local to regional scales. Yet decomposition rates differ dramatically when these controls do not. Fungal community dynamics are often invoked to explain these differences, suggesting that knowledge of ecosystem properties that influence fungal communities will improve understanding and projection of wood decomposition. We hypothesize that deadwood inputs decompose faster in forests with higher stocks of downed coarse woody material (CWM) because CWM is a resource from which lignocellulolytic fungi rapidly colonize new inputs. To test this hypothesis, we measure decomposition of 1,116 pieces of fine woody material (FWM) of five species, incubated for 13 to 49 months at five locations spanning 10 degrees-latitude in eastern U.S. forest. We place FWM pieces near and far from CWM across observational transects and experimental common gardens. Soil temperature positively affects location-level mean decomposition rates, but these among-location differences are smaller than within-location variation in decomposition. Some of this variability is caused by CWM, where FWM pieces next to CWM decompose more rapidly. These effects are greater with time of incubation and lower initial wood density of FWM. The effect size of CWM is of the same relative magnitude as for the known controls of temperature, deadwood density and diameter. Abundance data for CWM is available for many forests and hence may be an ecosystem variable amenable for inclusion in decomposition models. Our findings suggest that conservation efforts to rebuild depleted CWM stocks in temperate forests may accelerate decomposition of fresh deadwood inputs.
Resolving the Intricate Effects of Multiple Global Change Drivers on Root Litter Decomposition
Zhao, Qingzhou; Freschet, Grégoire T.; Tao, Tingting; et al. (2024)
Global Change Biology
Plant roots represent about a quarter of global plant biomass and constitute a primary source of soil organic carbon (C). Yet, considerable uncertainty persists regarding root litter decomposition and their responses to global change factors (GCFs). Much of this uncertainty stems from a limited understanding of the multifactorial effects of GCFs and it remains unclear how these effects are mediated by litter quality, soil conditions and microbial functionality. Using complementary field decomposition and laboratory incubation approaches, we assessed the relative controls of GCF-mediated changes in root litter traits and soil and microbial properties on fine-root decomposition under warming, nitrogen (N) enrichment, and precipitation alteration. We found that warming and N enrichment accelerated fine-root decomposition by over 10%, and their combination showed an additive effect, while precipitation reduction suppressed decomposition overall by 12%, with the suppressive effect being most significant under warming-alone and N enrichment-alone conditions. Significantly, changes in litter quality played a dominant role and accelerated fine-root decomposition by 15% ~ 18% under warming and N enrichment, while changes in soil and microbial properties were predominant and reduced decomposition by 7% ~ 10% under precipitation reduction and the combined warming and N enrichment. Examining only the decomposition environment or litter properties in isolation can distort global change effects on root decomposition, underestimating precipitation reduction impacts by 38% and overstating warming and N effects by up to 73%. These findings highlight that the net impact of GCFs on root litter decomposition hinges on the interplay between GCF-modulated root decomposability and decomposition environment, as well as on the synergistic or antagonistic relationships among GCFs themselves. Our study emphasizes that integrating the legacy effects of multiple GCFs on root traits, soil conditions and microbial functionality would improve our prediction of C and nutrient cycling under interactive global change scenarios.
Land-use- and climate-mediated variations in soil bacterial and fungal biomass across Europe and their driving factors
Siles, José A.; Vera, Alfonso; Díaz-López, Marta; et al. (2023)
Geoderma
Elucidating contents and drivers of soil bacterial and fungal biomass in contrasting land uses and climates at European scale is useful to define appropriate policies for the conservation of the ecosystem services that soil microorganisms provide. Here, we aimed to (i) quantify and compare bacterial and fungal biomass in 513 European soils collected from three different land uses (forests, grasslands, and croplands) and climates (arid, temperate, and cold) through analysis of fatty acid methyl esters; (ii) model the factors controlling soil bacterial and fungal biomass; and (iii) investigating levels of bacterial and fungal biomass in cropland soils cultivated with three important crop types in Europe: cereals, oil-producing crops, and orchards. Bacterial biomass decreased with land use in the following order: grasslands > croplands > forests and was found to be the highest in temperate environments. Similar patterns were found for biomass of Gram-positive and Gram-negative bacteria and Actinobacteria. Soil fungal biomass was greater in forests than in croplands and grasslands and was favoured by colder environments. The fungi to bacteria ratio (F/B) decreased as follows: forests > croplands > grasslands, with soils in colder climates showing greater F/B ratios in croplands and forests. Soil texture, soil organic carbon, and nitrogen were shown to directly drive bacterial and fungal biomass. The biomass of the different microbial groups was not influenced by the crop type when only croplands were considered. Fungi appear to be more susceptible to agricultural soil use than bacteria. Moreover, agricultural use of soil seems to buffer the effect of harsh climatic conditions on soil bacterial biomass. The present study improves our understanding of the combined effects of land use and climate on soil bacterial and fungal biomass across Europe.
Frontiers in soil ecology—Insights from the World Biodiversity Forum 2022
Eisenhauer, Nico; Bender, S. Franz; Calderón-Sanou, Irene; et al. (2022)
Journal of Sustainable Agriculture and Environment
Global change is affecting soil biodiversity and functioning across all terrestrial ecosystems. Still, much is unknown about how soil biodiversity and function will change in the future in response to simultaneous alterations in climate and land use, as well as other environmental drivers. It is crucial to understand the direct, indirect and interactive effects of global change drivers on soil communities and ecosystems across environmental contexts, not only today but also in the near future. This is particularly relevant for international efforts to tackle climate change like the Paris Agreement, and considering the failure to achieve the 2020 biodiversity targets, especially the target of halting soil degradation. Here, we outline the main frontiers related to soil ecology that were presented and discussed at the thematic sessions of the World Biodiversity Forum 2022 in Davos, Switzerland. We highlight multiple frontiers of knowledge associated with data integration, causal inference, soil biodiversity and function scenarios, critical soil biodiversity facets, underrepresented drivers, global collaboration, knowledge application and transdisciplinarity, as well as policy and public communication. These identified research priorities are not only of immediate interest to the scientific community but may also be considered in research priority programmes and calls for funding.
Liquor fermentation industry reshapes soil microbiomes and drives CO2 emissions via microbial dispersal
Zheng , Yifu; Crowther, Tom; Qin , Yue; et al. (2025)
Journal of Environmental Management
The rapid expansion of industrial fermentation has raised concerns about its environmental impacts, particularly regarding microbial dispersal from production facilities into adjacent terrestrial ecosystems; however, the ecological and functional consequences of microbial introductions originating from fermentation facilities remain poorly elucidated. We studied eight Chinese liquor fermentation facilities spanning 26°-47°N and 83°-124°E, covering the major geographical range of the industry. Using large-scale soil metagenomics, in situ CO2 flux measurements, and microcosm experiments, we demonstrate that industrial fermentation significantly alters local soil microbial communities and enhances carbon decomposition potential. The results showed that soil carbon decomposition genes increased 13.6 % around fermentation facilities. Biologically, the fermentation process at the facilities introduced microorganisms into soil, such as Actinobacteria, whose abundance increased by 2.8 %. These microorganisms directly increased the abundance of carbon decomposition genes in the soil, while Actinobacteria also enhance soil carbon decomposition capacity by reducing microbial α diversity. Abiotically, the soil total carbon increased by 3–89 % around facilities, thereby enriching carbon decomposition genes. These soil microbial activities changed by fermentation facilities lead to an increase in soil CO2 emissions. Our study provides the first evidence that industrial fermentation facilities inadvertently modify soil microbial community and function. These findings establish a critical link between fermented food production systems and terrestrial carbon emissions, with important implications for sustainable fermentation practices and climate-smart industrial planning.

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