Browsing by Autor "Peter B. Reich"

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Dominance and rarity in tree communities across the globe: Patterns, predictors and threats
(Wiley, 2024) Iris Hordijk; Lalasia Bialic‐Murphy; T. Bruce Lauber; Devin Routh; Lourens Poorter; Malin Rivers; Hans ter Steege; Jingjing Liang; Peter B. Reich; Sergio de‐Miguel
Abstract Aim Ecological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree communities? (2) Which ecological and anthropogenic factors predict these patterns? And (3) what is the extinction risk of locally dominant and rare tree species? Location Global. Time period 1990–2017. Major taxa studied Trees. Methods We used 1.2 million forest plots and quantified local tree dominance as the relative plot basal area of the single most dominant species and local rarity as the percentage of species that contribute together to the least 10% of plot basal area. We mapped global community dominance and rarity using machine learning models and evaluated the ecological and anthropogenic predictors with linear models. Extinction risk, for example threatened status, of geographically widespread dominant and rare species was evaluated. Results Community dominance and rarity show contrasting latitudinal trends, with boreal forests having high levels of dominance and tropical forests having high levels of rarity. Increasing annual precipitation reduces community dominance, probably because precipitation is related to an increase in tree density and richness. Additionally, stand age is positively related to community dominance, due to stem diameter increase of the most dominant species. Surprisingly, we find that locally dominant and rare species, which are geographically widespread in our data, have an equally high rate of elevated extinction due to declining populations through large‐scale land degradation. Main conclusions By linking patterns and predictors of community dominance and rarity to extinction risk, our results suggest that also widespread species should be considered in large‐scale management and conservation practices.
Effect of climate on traits of dominant and rare tree species in the world’s forests
(Nature Portfolio, 2025) Iris Hordijk; Lourens Poorter; Jingjing Liang; Peter B. Reich; Sergio de‐Miguel; G.J. Nabuurs; Javier G. P. Gamarra; Han Y. H. Chen; Mo Zhou; Susan K. Wiser
Evenness mediates the global relationship between forest productivity and richness
(Wiley, 2023) Iris Hordijk; Daniel S. Maynard; Simon P. Hart; Lidong Mo; Hans ter Steege; Jingjing Liang; Sergio de‐Miguel; G.J. Nabuurs; Peter B. Reich; Meinrad Abegg
Abstract 1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis . Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions.
Integrated global assessment of the natural forest carbon potential
(Nature Portfolio, 2023) Lidong Mo; Constantin M. Zohner; Peter B. Reich; Jingjing Liang; Sergio de‐Miguel; G.J. Nabuurs; Susanne S. Renner; Johan van den Hoogen; Arnan Araza; Martin Herold
The global distribution and drivers of wood density and their impact on forest carbon stocks
(Nature Portfolio, 2024) Lidong Mo; Thomas W. Crowther; Daniel S. Maynard; Johan van den Hoogen; Haozhi Ma; Lalasia Bialic‐Murphy; Jingjing Liang; Sergio de‐Miguel; G.J. Nabuurs; Peter B. Reich
The number of tree species on Earth
(National Academy of Sciences, 2022) Roberto Cazzolla Gatti; Peter B. Reich; Javier G. P. Gamarra; Thomas W. Crowther; Cang Hui; Albert Morera; Jean‐François Bastin; Sergio de‐Miguel; G.J. Nabuurs; Jens‐Christian Svenning
One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness.