ORCID Profile
0000-0003-0674-2577
Current Organisation
IT University of Copenhagen
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Publisher: Research Square Platform LLC
Date: 05-01-2023
DOI: 10.21203/RS.3.RS-2394473/V1
Abstract: Fundamental axes of variation in plant traits result from trade-offs between costs and benefits of resource-use strategies at the leaf scale. However, it is unclear whether trade-offs and optimality principles in functional traits of leaves are conserved at the ecosystem level. We tested three well-known leaf- and plant-level coordination theories at the ecosystem scale: the leaf economics spectrum, the global spectrum of plant form and function, and the least-cost hypothesis. We combined ecosystem functional properties from 98 FLUXNET sites, vegetation properties, and ecosystem-level plant traits into three corresponding principal component analyses. Coordination is conserved at the ecosystem scale. However, additional processes occur at the ecosystem level compared to the leaf scale, highlighting the importance of scale-emergent properties in understanding and predicting ecosystem behaviour. Evaluating the coordination of ecosystem functional properties supports the development of more realistic global dynamic vegetation models with critical empirical data, reducing the uncertainty of climate change projections.
Publisher: Wiley
Date: 31-12-2019
DOI: 10.1111/GCB.14904
Abstract: Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to bio ersity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on in idual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
Publisher: Cold Spring Harbor Laboratory
Date: 23-04-2020
DOI: 10.1101/2020.04.21.052464
Abstract: Although trees are key to ecosystem functioning, many forests and tree species across the globe face strong threats. Preserving areas of high bio ersity is a core priority for conservation however, different dimensions of bio ersity and varied conservation targets make it difficult to respond effectively to this challenge. Here, we ( i ) identify priority areas for global tree conservation using comprehensive coverage of tree ersity based on taxonomy, phylogeny, and functional traits and ( ii ) compare these findings to existing protected areas and global bio ersity conservation frameworks. We find that ca . 51% of the top-priority areas for tree bio ersity are located in current protected areas. The remaining half top-priority areas are subject to moderate to high human pressures, indicating conservation actions are needed to mitigate these human impacts. Our findings emphasize the effectiveness of using tree conservation priority areas for future global conservation planning.
Publisher: Wiley
Date: 24-09-2023
DOI: 10.1111/NPH.19276
Publisher: Springer Science and Business Media LLC
Date: 04-07-2023
DOI: 10.1038/S41467-023-39572-5
Abstract: Fundamental axes of variation in plant traits result from trade-offs between costs and benefits of resource-use strategies at the leaf scale. However, it is unclear whether similar trade-offs propagate to the ecosystem level. Here, we test whether trait correlation patterns predicted by three well-known leaf- and plant-level coordination theories – the leaf economics spectrum, the global spectrum of plant form and function, and the least-cost hypothesis – are also observed between community mean traits and ecosystem processes. We combined ecosystem functional properties from FLUXNET sites, vegetation properties, and community mean plant traits into three corresponding principal component analyses. We find that the leaf economics spectrum (90 sites), the global spectrum of plant form and function (89 sites), and the least-cost hypothesis (82 sites) all propagate at the ecosystem level. However, we also find evidence of additional scale-emergent properties. Evaluating the coordination of ecosystem functional properties may aid the development of more realistic global dynamic vegetation models with critical empirical data, reducing the uncertainty of climate change projections.
Publisher: Cold Spring Harbor Laboratory
Date: 17-11-2020
DOI: 10.1101/2020.11.14.382846
Abstract: Both historical and contemporary environmental conditions determine present bio ersity patterns, but their relative importance is not well understood. One way to disentangle their relative effects is to assess how different dimensions of beta- ersity relate to past climatic changes, i.e., taxonomic, phylogenetic and functional compositional dissimilarity, and their components generated by replacement of species, lineages and traits (turnover) and richness changes (nestedness). Here, we quantify global patterns of each of these aspects of beta- ersity among neighboring sites for angiosperm trees using the most extensive global database of tree species-distributions (43,635 species). We found that temperature change since the Last Glacial Maximum (LGM) was the major influence on both turnover and nestedness components of beta- ersity, with a negative correlation to turnover and a positive correlation to nestedness. Moreover, phylogenetic and functional nestedness was higher than expected from taxonomic beta- ersity in regions that experienced large temperature changes since the LGM. This pattern reflects relatively greater losses of phylogenetic and functional ersity in species-poor assemblages, possibly caused by phylogenetically and functionally selective species extinction and recolonization during glacial-interglacial oscillations. Our results send a strong warning that rapid anthropogenic climate change is likely to result in a long-lasting phylogenetic and functional compositional simplification, potentially impairing forest ecosystem functioning.
Publisher: Elsevier BV
Date: 11-2011
Publisher: Wiley
Date: 31-07-2019
DOI: 10.1111/ELE.13361
Abstract: While bio ersity loss continues globally, assessments of regional and local change over time have been equivocal. Here, we assess changes in plant species richness and beta ersity over 140 years at the level of regions within a country. Using 19th-century flora censuses for 14 Danish regions as a baseline, we overcome previous criticisms concerning short time series and neglect of completely altered habitats. We find that species composition has changed dramatically and directionally across all regions. Substantial species losses were more than offset by large gains, resulting in a net increase in species richness in all regions. The occupancy of initially widespread species increased, while initially rare species lost terrain. These changes were accompanied by strong biotic homogenization i.e. regions are more similar now than they were 140 years ago. Species declining in Denmark were found to be in similar decline all over Northern Europe.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-04-2023
Abstract: As Earth’s climate has varied strongly through geological time, studying the impacts of past climate change on bio ersity helps to understand the risks from future climate change. However, it remains unclear how paleoclimate shapes spatial variation in bio ersity. Here, we assessed the influence of Quaternary climate change on spatial dissimilarity in taxonomic, phylogenetic, and functional composition among neighboring 200-kilometer cells (beta- ersity) for angiosperm trees worldwide. We found that larger glacial-interglacial temperature change was strongly associated with lower spatial turnover (species replacements) and higher nestedness (richness changes) components of beta- ersity across all three bio ersity facets. Moreover, phylogenetic and functional turnover was lower and nestedness higher than random expectations based on taxonomic beta- ersity in regions that experienced large temperature change, reflecting phylogenetically and functionally selective processes in species replacement, extinction, and colonization during glacial-interglacial oscillations. Our results suggest that future human-driven climate change could cause local homogenization and reduction in taxonomic, phylogenetic, and functional ersity of angiosperm trees worldwide.
Publisher: Proceedings of the National Academy of Sciences
Date: 28-05-2021
Abstract: Invasive alien species pose major threats to bio ersity and ecosystems. However, identifying drivers of invasion success has been challenging, in part because species can achieve invasiveness in different ways, each corresponding to different aspects of demographics and distribution. Employing a multidimensional perspective of invasiveness to Europe’s alien flora, we find species generally fall along an axis from overall poor invaders to super invaders that become abundant, widespread, and invade erse habitats. Some species that deviate from this pattern are recently introduced and still spreading, but others represent atypical forms of invasiveness. In addition to identifying species traits and ecological circumstances associated with super invaders (e.g., intercontinental introductions), we explore drivers in atypical invasions, providing increased clarity into invasion processes.
Publisher: Proceedings of the National Academy of Sciences
Date: 16-06-2022
Abstract: Safeguarding Earth’s tree ersity is a conservation priority due to the importance of trees for bio ersity and ecosystem functions and services such as carbon sequestration. Here, we improve the foundation for effective conservation of global tree ersity by analyzing a recently developed database of tree species covering 46,752 species. We quantify range protection and anthropogenic pressures for each species and develop conservation priorities across taxonomic, phylogenetic, and functional ersity dimensions. We also assess the effectiveness of several influential proposed conservation prioritization frameworks to protect the top 17% and top 50% of tree priority areas. We find that an average of 50.2% of a tree species’ range occurs in 110-km grid cells without any protected areas (PAs), with 6,377 small-range tree species fully unprotected, and that 83% of tree species experience nonnegligible human pressure across their range on average. Protecting high-priority areas for the top 17% and 50% priority thresholds would increase the average protected proportion of each tree species’ range to 65.5% and 82.6%, respectively, leaving many fewer species (2,151 and 2,010) completely unprotected. The priority areas identified for trees match well to the Global 200 Ecoregions framework, revealing that priority areas for trees would in large part also optimize protection for terrestrial bio ersity overall. Based on range estimates for ,000 tree species, our findings show that a large proportion of tree species receive limited protection by current PAs and are under substantial human pressure. Improved protection of bio ersity overall would also strongly benefit global tree ersity.
Publisher: Cold Spring Harbor Laboratory
Date: 03-06-2020
DOI: 10.1101/2020.06.02.128975
Abstract: Trees are of vital importance for ecosystem functioning and services at local to global scales, yet we still lack a detailed overview of the global patterns of tree ersity and the underlying drivers, particularly the imprint of paleoclimate. Here, we present the high-resolution (110 km) worldwide mapping of tree species richness, functional and phylogenetic ersities based on ∼7 million quality-assessed occurrences for 46,752 tree species (80.5% of the estimated total number of tree species), and subsequent assessments of the influence of paleo-climate legacies on these patterns. All three tree ersity dimensions exhibited the expected latitudinal decline. Contemporary climate emerged as the strongest driver of all ersity patterns, with Pleistocene and deeper-time ( 7 years) paleoclimate as important co-determinants, and, notably, with past cold and drought stress being linked to reduced current ersity. These findings demonstrate that tree ersity is affected by paleoclimate millions of years back in time and highlight the potential for tree ersity losses from future climate change.
No related grants have been discovered for Hans Henrik Bruun.