Biology subjects

Reich, P. B.

Publications and source records attributed to Reich, P. B..

15 recordsLinked to original sources

bioRxiv2026

Ecological context shapes the interpretation of biodiversity intactness metrics

Developing biodiversity metrics that are both operational for decision-making and ecologically meaningful remains challenging. Mean Species Abundance (MSA) is widely used to quantify biodiversity intactness in applications including biodiversity scenario modeling, spatial assessment, policy and planning, and life cycle assessment (LCA). MSA compares species abundance under disturbed conditions with their abundance under a reference condition, but the pressure-impact relationships used to calculate it are generalized across studies and may not adequately represent variation among ecological contexts or taxonomic groups. This is particularly relevant when MSA is transferred across regions or used to support comparisons and environmental decision-making. We compiled biodiversity data from 7,064 forest fragments containing 21,761 species of arthropods, amphibians, birds, mammals, squamates, and plants across 11 biomes worldwide. We evaluated how MSA relates to broader ecological outcomes, including local and regional species richness and ecosystem productivity, and whether these relationships vary across ecological contexts (vegetation condition, landscape structure, and biome) and taxonomic groups. MSA was positively associated with local species richness and ecosystem productivity across all sites, but these associations weakened, disappeared, or reversed depending on ecological context and taxonomic group. For example, the MSA-productivity association held in only five of 11 biomes, and the MSA-regional richness association was negative in temperate conifer and boreal forests but positive in four other biomes. We propose a simple decision guide linking assessment goals, contextual evaluation, and interpretation to help identify when MSA can be used directly, when ecological context should guide its interpretation, and when complementary ecological information is needed. These findings may extend to other biodiversity metrics that compare impacted conditions with reference states and apply generalized impact relationships across ecological contexts and taxonomic groups.

ecology↗

bioRxiv2026

Prior low-severity fires reduce the risk of persistent forest loss from subsequent fires

Intensifying fire regimes threaten forests globally, but the risk of persistent post-fire forest loss and its potential mitigation remains poorly quantified. We analyzed millions of wildfires worldwide from 2001 to 2024 and tracked recovery in satellite-observed forest structure and ecosystem function. Post-fire persistent forest loss, indicated by modeled non-recovery to pre-fire conditions over decadal timescales, affected 57.1% of burned forest area globally since 2001, with hotspots in Pacific temperate and southern boreal forests. We then identified 'crucial fires' as events exceeding a stringent modeled-risk probability threshold for persistent structural or functional non-recovery, with fire severity strongly predicting this loss. This severity dependence revealed a management pathway, as locations with prior low-severity fire experienced lower severity in subsequent wildfires and had lower modeled probability of becoming crucial. Under a model-based counterfactual scenario, applying the estimated severity attenuation was associated with a 7.6% reduction; the top 1% of road-accessible areas accounted for 35% of this reduction. These results provide a global framework for identifying where wildfire threatens forest resistance and where targeted low-severity fire management like prescribed fire might be used to combat global forest loss.

ecology↗

bioRxiv2026

Primary productivity declines when species composition and climate are mismatched

Climate change drives shifts in species composition, but turnover in many communities lags behind the current pace of change. Anticipating the impact of the resulting community-climate disequilibria on ecosystem functioning is critical. Present-day communities may already be out of equilibrium with climate, providing an opportunity to estimate the effects of disequilibrium before they become more widespread. We analyzed plant community composition and function data from [~]60,000 rangeland monitoring sites across the western US to measure how community-climate disequilibrium contributes to spatial and temporal variation in net primary productivity (NPP) - a key ecosystem function. We found that communities were already substantially out of equilibrium with climate and accounting for this disequilibrium helped explain patterns of NPP. Communities farthest from equilibrium were less productive than those that were closely matched with climate. Our findings suggest that future increases in community-climate disequilibrium may further impair ecosystem functioning.

ecology↗

bioRxiv2025

Leaf microbiome assembly is linked to plant phylogeny

Background and AimsThe plant microbiome is considered as an extended part of the plant genome, and it provides key functions in regulating plant fitness, and stress tolerance. Plants and associated microbiomes have co-evolved over millennia, yet evidence for a strong influence of plant phylogeny in influencing their microbiomes is largely lacking. Our main aims was to identify key drivers of plant microbiome assembly. MethodsHere, we conducted a full factorial experiment that included three levels of soil microbial diversity, five plant species from three functional groups (C3, C4, and C3 nitrogen-fixing), and two moisture availability levels. ResultsOur results showed that host identity and plant functional group exerted the strongest effect on leaf microbial assembly, while root and soil microbiomes showed less sensitivity to host selection. The initial soil microbial diversity and community structure significantly impacted soil and root microbial composition, but not leaf microbiomes. Importantly, we observed significant positive linkage between host phylogeny distance and Bray-Curtis dissimilarity index in leaf microbiomes. This finding was further validated through analysis of microbiome data from seven plant species grown across different field and environmental conditions. Interestingly, there was no significant impact of short-term water stress on plant microbial communities. ConclusionsBy providing empirical evidence for important role of host selection in shaping plant microbiomes, this study advances our fundamental knowledge of plant-microbe interactions and their co-evolutionary relationships, and enhances our ability to develop future tools harnessing plant microbiome to improve plant health and productivity.

microbiology↗

bioRxiv2025

Warming makes 20 boreal species grow earlier but not always taller

Climate warming is altering the timing of seasonal growth in cold-temperate and boreal ecosystems, with potential consequences for forests on multiple continents. It has been hypothesized that in a warming climate, earlier growth in spring might lead to a longer growing season and thus higher annual total growth. However, whether the period of active growth is longer in a warming climate is unclear, as is whether changes in growth rate might reinforce or offset the effect of changing growing season length in modulating annual total growth. Understanding responses in growth to warming is crucial to projecting forest dynamics under future climate change. To address this, we experimentally warmed (by +1.62 and 3.26 {degrees}C on average) open-air southern boreal forest plots for 14 years (2010 to 2023) and measured juvenile height growth from spring until fall for 20 tree and shrub species, with a total of 11,565 individual-year growth trajectories. Across all species and in various canopy (open, closed) and rainfall (ambient, reduced) contexts, experimental warming consistently advanced the timing of height growth (4.32 days per 3 {degrees}C warming). However, species differed in their annual total growth responses. Evergreen gymnosperms such as spruce, fir, and pine tended to exhibit suppressed annual total growth under warming (-15.8% per 3 {degrees}C warming), driven by a shorter duration of active growth, despite an earlier start, with little change in relative growth rate. In contrast, deciduous angiosperms and non-native shrubs often show enhanced annual total growth under warming (19.3 and 37.4% per 3 {degrees}C warming), driven by faster rate, longer duration, or a combination of both. More broadly, species with a more conservative lifestyle responded less positively in the duration and rate of growth, thus placing them at a disadvantage under warming. These contrasting responses challenge assumptions that an earlier start of the growing season universally enhances growth and highlight how warming may shift both the timing and pace of growth and thus alter community composition within mixed-species forests.

ecology↗

bioRxiv2025

Warming and reduced rainfall alter fungal necromass decomposition rates and associated microbial community composition and functioning at a temperate-boreal forest ecotone

Changes in temperature and rainfall regimes will have significant yet potentially contrasting impacts on rates of soil organic matter (SOM) decomposition. To assess how a combined stress treatment of warming and drought impacts the decomposition of fungal necromass--a fast-cycling soil organic matter (SOM) pool--we incubated Hyaloscypha bicolor necromass under both ambient and altered conditions (air and soil warming +3.3{degrees}C and [~]40% reduced rainfall) at the B4Warmed experiment in Minnesota, USA. We conducted two multi-week incubations, one assessing mass loss and microbial community composition on decaying necromass after 1, 2, 7, and 14 weeks and the second characterizing the substrate utilization capacities of necromass- associated microbial communities after weeks 1 and 7. Warming and reduced rainfall significantly accelerated the initial rate of necromass decay by [~]20%, but overall mass loss was not different between treatments at the end of the 14-week incubation. The accelerated initial rate of decay paralleled shifts in microbial community composition and activity in the altered plots, demonstrating a higher metabolic capability to utilize C and N substrates early in decomposition but a lower capability later in decay. These findings highlight the dynamic, stage-dependent response of fungal necromass decomposition to altered climate regimes, underscoring the importance of considering both temporal dynamics and the functional capacity of microbial communities when assessing the impacts of climate change on soil carbon and nutrient cycling in forest ecosystems.

ecology↗

bioRxiv2024

Thermal acclimation of stem respiration reduces global carbon burden

Stem respiration is a key driver of carbon flux from ecosystems to the atmosphere, yet its response to global warming remains poorly constrained. In particular it has been proposed that stem respiration acclimates to changing temperatures, which could have large implications for carbon cycling under climate change, but no theory exists to predict acclimated respiration rates. Here, we hypothesized that stem respiration is physiologically linked to transpiration in order to maintain hydraulic continuity. We then use that linkage, combined with Eco-evolutionary optimality theory, to develop a theoretical prediction of the temperature sensitivity of both acclimated and instantaneous stem respiration. Leveraging an extensive global dataset, we observe temperature sensitivities of stem respiration across geographical and seasonal variations that are consistent with this prediction. Our findings reveal that stem respiration contributes approximately a quarter of the global above-ground auto-trophic respiration, with an estimated annual emission of around 11.20 {+/-} 5.88 Pg C--comparable to total anthropogenic emissions. Importantly, incorporating thermal acclimation of stem respiration into projections significantly reduces predicted land ecosystem carbon emissions by 4.41 and 9.56 Pg C under the SSP126 and SSP585 scenarios, respectively, for the 21st century.

ecology↗

bioRxiv2022

The recovery of biodiversity and species composition after agricultural abandonment across spatial scales

O_LIHuman impacts have led to dramatic biodiversity change which can be highly scale-dependent across space and time. A primary means to manage these changes is via passive (here, the removal of disturbance) or active (management interventions) ecological restoration. The recovery of biodiversity, following the removal of disturbance is often incomplete relative to some kind of reference target. The magnitude of recovery of ecological systems following disturbance depend on the landscape matrix, as well as the temporal and spatial scales at which biodiversity is measured. C_LIO_LIWe measured the recovery of biodiversity and species composition over 27 years in 17 temperate grasslands abandoned after agriculture at different points in time, collectively forming a chronosequence since abandonment from one to eighty years. We compare these abandoned sites with known agricultural land-use histories to never-disturbed sites as relative benchmarks. We specifically measured aspects of diversity at the local plot-scale (-scale, 0.5m2) and site-scale ({gamma}-scale, 10m2), as well as the within-site heterogeneity ({beta}-diversity) and among-site variation in species composition (turnover and nestedness). C_LIO_LIAt our -scale, sites recovering after agricultural abandonment only had 70% of the plant species richness (and [~]30% of the evenness), compared to never-ploughed sites. Within-site {beta}-diversity recovered following agricultural abandonment to around 90% after 80 years. This effect, however, was not enough to lead to recovery at our {gamma}-scale. Richness in recovering sites was [~]65% of that in remnant never-ploughed sites. The presence of species characteristic of the never disturbed sites increased in the recovering sites through time. Forb and legume cover declines in years since abandonment, relative to graminoid cover across sites. C_LIO_LISynthesis. We found that, during the 80 years after agricultural abandonment, old-fields did not recover to the level of biodiversity in remnant never-ploughed sites at any scale. {beta}-diversity recovered more than -scale or {gamma}-scales. Plant species composition recovered, but not completely, over time, and some species groups increased their cover more than others. Patterns of ecological recovery in degraded ecosystems across space and long time-scales can inform effective, targeted active restoration interventions and perhaps, lead to better outcomes. C_LI

ecology↗

bioRxiv2022

Higher aboveground carbon stocks in mixed-species planted forests than monocultures - a meta-analysis

Natural forest is declining globally as the area of planted forest increases. Planted forests are often monocultures, despite results suggesting that higher species richness improves ecosystem functioning and stability. To test if this is generally the case, we performed a meta-analysis of available results. We assessed aboveground carbon stocks in mixed-species planted forests vs (a) the average of constituent species monocultures, (b) the best constituent species monoculture, and (c) commercial species monocultures. We investigated whether any advantage of mixtures over monocultures was positively related to species richness, as well as potential mechanisms driving differences in carbon stocks between mixtures and monocultures. The meta-analysis dataset included 79 comparisons from 21 sites. Carbon stocks in mixed planted forests were higher than the average of stocks in monocultures of their constituent species, containing on average 70% more carbon. Mixed planted forests also out-performed commercial monocultures, containing on average 77% more carbon. There was c.25% more carbon in mixed planted forests relative to the best performing monocultures, although this difference was not statistically significant. Overyielding was highest in four-species mixtures (richness range 2-6 species). More data providing better coverage of richness and age gradients (study sites aged 3.5-28 years) is needed to increase confidence in these results. None of the potential mechanisms we examined (nitrogen-fixer present vs absent; native vs non-native/mixed origin; tree diversity experiment vs forestry plantation) consistently explained variation in the diversity effects. This suggests that our findings are driven by a combination of small (statistically insignificant) effects from these sources or further unidentified mechanisms or some combination of the two. We conclude that increasing tree species richness in planted forests can increase carbon stocks while bringing other potential benefits associated with diversification. However, implementation will depend on the balance of these benefits relative to the operational challenges and costs of diversification.

ecology↗

bioRxiv2020

Biotic and abiotic drivers of soil microbial functions across tree diversity experiments

AimSoil microorganisms are essential for the functioning of terrestrial ecosystems. Although soil microbial communities and functions may be linked to the tree species composition and diversity of forests, there has been no comprehensive study of how general potential relationships are and if these are context-dependent. A global network of tree diversity experiments (TreeDivNet) allows for a first examination of tree diversity-soil microbial function relationships across environmental gradients. LocationGlobal Major Taxa StudiedSoil microorganisms MethodsSoil samples collected from eleven tree diversity experiments in four biomes across four continents were used to measure soil basal respiration, microbial biomass, and carbon use efficiency using the substrate-induced respiration method. All samples were measured using the same analytical device in the same laboratory to prevent measurement bias. We used linear mixed-effects models to examine the effects of tree species diversity, environmental conditions, and their interactions on soil microbial functions. ResultsAcross biodiversity experiments, abiotic drivers, mainly soil water content, significantly increased soil microbial functions. Potential evapotranspiration (PET) increased, whereas soil C-to-N ratio (CN) decreased soil microbial functions under dry soil conditions, but high soil water content reduced the importance of other abiotic drivers. Tree species richness and phylogenetic diversity had overall similar, but weak and context-dependent (climate, soil abiotic variables) effects on soil microbial respiration. Positive tree diversity effects on soil microbial respiration were most pronounced at low PET, low soil CN, and high tree density. Soil microbial functions increased with the age of the experiment. Main conclusionsOur results point at the importance of soil water content for maintaining high levels of soil microbial functions and modulating effects of other environmental drivers. Moreover, overall tree diversity effects on soil microbial functions seem to be negligible in the short term (experiments were 1-18 years old). However, context-dependent tree diversity effects (climate, soil abiotic variables) have greater importance at high tree density, and significant effects of experimental age call for longer-term studies. Such systematic insights are key to better integrate soil carbon dynamics into the management of afforestation projects across environmental contexts, as todays reforestation efforts remain focused largely on aboveground carbon storage and are still dominated by less diverse forests stands of commercial species.

ecology↗

bioRxiv2019

The results of biodiversity-ecosystem functioning experiments are realistic

A large body of research shows that biodiversity loss can reduce ecosystem functioning, thus providing support for the conservation of biological diversity1-4. Much of the evidence for this relationship is drawn from biodiversity-ecosystem functioning experiments (hereafter: biodiversity experiments), in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured5-9. This random assembly has led some ecologists to question the relevance of biodiversity experiments to real-world ecosystems, where community assembly may often be non-random and influenced by external drivers, such as climate or land-use intensification10-18. Despite these repeated criticisms, there has been no comprehensive, quantitative assessment of how experimental and real-world plant communities really differ, and whether these differences invalidate the experimental results. Here, we compare data from two of the largest and longest-running grassland biodiversity experiments globally (Jena Experiment, Germany; BioDIV, USA) to related real-world grassland plant communities in terms of their taxonomic, functional, and phylogenetic diversity and functional-trait composition. We found that plant communities of biodiversity experiments have greater variance in these compositional features than their real-world counterparts, covering almost all of the variation of the real-world communities (82-96%) while also containing community types that are not currently observed in the real world. We then re-analysed a subset of experimental data that included only ecologically-realistic communities, i.e. those comparable to real-world communities. For ten out of twelve biodiversity-ecosystem functioning relationships, biodiversity effects did not differ significantly between the full dataset of biodiversity experiments and the ecologically-realistic subset of experimental communities. This demonstrates that the results of biodiversity experiments are largely insensitive to the inclusion/exclusion of unrealistic communities. By bridging the gap between experimental and real-world studies, these results demonstrate the validity of inferences from biodiversity experiments, a key step in translating their results into specific recommendations for real-world biodiversity management.

ecology↗

bioRxiv2019

The fate of carbon in a mature forest under carbon dioxide enrichment

Atmospheric carbon dioxide enrichment (eCO2) can enhance plant carbon uptake and growth1,2,3,4,5, thereby providing an important negative feedback to climate change by slowing the rate of increase of the atmospheric CO2 concentration6. While evidence gathered from young aggrading forests has generally indicated a strong CO2 fertilization effect on biomass growth3,4,5, it is unclear whether mature forests respond to eCO2 in a similar way. In mature trees and forest stands7,8,9,10, photosynthetic uptake has been found to increase under eCO2 without any apparent accompanying growth response, leaving an open question about the fate of additional carbon fixed under eCO24, 5, 7,8,9,10,11. Here, using data from the first ecosystem-scale Free-Air CO2 Enrichment (FACE) experiment in a mature forest, we constructed a comprehensive ecosystem carbon budget to track the fate of carbon as the forest responds to four years of eCO2 exposure. We show that, although the eCO2 treatment of ambient +150 ppm (+38%) induced a 12% (+247 gCm-2yr-1) increase in carbon uptake through gross primary production, this additional carbon uptake did not lead to increased carbon sequestration at the ecosystem level. Instead, the majority of the extra carbon was emitted back into the atmosphere via several respiratory fluxes, with increased soil respiration alone contributing [~]50% of the total uptake surplus. Our results call into question the predominant thinking that the capacity of forests to act as carbon sinks will be generally enhanced under eCO2, and challenge the efficacy of climate mitigation strategies that rely on CO2 fertilization as a driver of increased carbon sinks in standing forests and afforestation projects.

ecology↗

bioRxiv2019

A universal scaling method for biodiversity-ecosystem functioning relationships

Global biodiversity is declining at rates faster than at any other point in human history. Experimental manipulations of biodiversity at small spatial scales have demonstrated that communities with fewer species consistently produce less biomass than higher diversity communities. However, understanding how the global extinction crisis is likely to impact global ecosystem functioning will require applying these local and largely experimental findings to natural systems at substantially larger spatial and temporal scales. Here we propose that we can use two simple macroecological patterns - the species area curve and the biomass-area curve - to upscale the species richness-biomass relationship. We demonstrate that at local spatial scales, each additional species will contribute more to biomass production with increasing area sampled because the species-area curve saturates and the biomass-area curve increases monotonically. We use species-area and biomass-area curves from a Minnesota grassland and a Panamanian tropical dry forest to examine the species richness - biomass relationship at three and ten sampling extents, respectively. In both datasets, the observed relationship between biodiversity and biomass production at every sampling extent was predicted from simple species-area and biomass-area relationships. These findings suggest that macroecological patterns like the species-area curve underpin the scaling of biodiversity-ecosystem functioning research and can be used to predict these relationships at the global scales where they are relevant for species loss.

ecology↗

bioRxiv2019

Top-down and bottom-up controls on soil carbon and nitrogen cycling with repeated burning across four ecosystems

Fires shape the biogeochemistry and functioning of many ecosystems, but fire frequencies are changing across large areas of the globe. Frequent fires can change soil carbon (C) and nitrogen (N) storage through both "top-down" pathways, by altering inputs through shifting plant composition and biomass, and "bottom-up" ones, by altering losses through decomposition and turnover of soil organic matter. However, the relative importance of these different pathways and the degree to which they regulate ecosystem responses to decades of changing fire frequencies is uncertain. Here, we sampled soils and plant communities in four North American and African sites spanning tropical savanna, temperate coniferous savanna, temperate broadleaf savanna, and temperate coniferous forest that each contained multiple plots repeatedly burned for 33-61 years and nearby plots that were protected from fire over the same period. The sites varied markedly in temperature, precipitation, species composition, fire history and soil chemistry; thus they represent a broad test for the generality of fire impacts on biogeochemical cycling. For all four sites, bulk soil C and N by were 25-180% higher in unburned vs. frequently burned plots, with greater soil losses occurring in areas with greater declines in tree cover and biomass inputs into soils. Fire reduced the activity of soil extracellular enzymes that hydrolyze labile C and N from soil organic matter by two- to ten-fold, whereas tree cover was the predominant control on the oxidation of recalcitrant C compounds. C-acquisition enzyme activity tended to decline with decreasing soil N, suggesting that N losses may contribute to limited decomposition, buffering systems against increased losses of soil C with fire. In conclusion, variability in how fire alters soil C and N across ecosystems can be explained partly by fire-driven changes in tree cover and biomass, but the slower turnover of organic matter we observed may offset some of the reduction of C inputs from plants after fire.

ecology↗

bioRxiv2018

Diversity-dependent plant-soil feedbacks underlie long-term plant diversity effects on primary productivity

Although diversity-dependent plant-soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influence of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for [≥]12 years from two grassland biodiversity experiments. Model plant communities differing in diversity were grown in soils conditioned by plant communities with either low- or high-diversity (soil history). Our results reveal that plant diversity can modify plant productivity through both diversity-mediated plant-plant and plant-soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. The underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, nematode richness and soil nitrogen availability). Thus, effects of plant diversity loss on ecosystem functioning may persist or even increase over time because of biotic and abiotic soil legacy effects.

ecology↗