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Towards a Global Tree Assessment
Abstract
Although trees have high economic, cultural and ecological value, increasing numbers of species are potentially at risk of extinction because of forest loss and degradation as a result of human activities, including overharvesting, fire and grazing. Emerging threats include climate change and its interaction with the spread of pests and diseases. The impact of such threats on the conservation status of trees is poorly understood. Here we highlight the need to conduct a comprehensive conservation assessment of the world's tree species, building on previous assessments undertaken for the IUCN Red List. We suggest that recent developments in plant systematics, online databases, remote sensing data and associated analytical tools offer an unprecedented opportunity to conduct such an assessment. We provide an overview of how a Global Tree Assessment could be achieved in practice, through participative, open-access approaches to data sharing and evaluation.
... According to Botanic Gardens Conservation International (BGCI, 2021a, 2021b), approximately 58,000 tree species are currently known to science and published in the GTS database. At least 30% of these have been identified as threatened, with forest clearance and habitat loss being the greatest threats (Newton et al., 2015). Moreover, Guo et al. (2022) found that about 83% of 46,000 tree species analysed were estimated to be subjected to moderate to very high human pressure. ...
... Noteworthy, efforts to survey global plant diversity include the sPlot database, which collated over 1 million vegetation plots and 23 million plant species data worldwide(Bruelheide et al., 2019). Also, as part of the BGCI initiative to assess conservation status of global tree diversity, extensive field surveys have been conducted to collect tree species abundance data in many countries(Newton et al., 2015). Although biases and limitations exist in such expert assessments and targeted surveys, they have produced valuable additional information about tree species from around the world(Bruelheide et al., 2019;Keppel, Craven, et al., 2021;Keppel, Peters, et al., 2021). ...
Aim
Recent unprecedented efforts to digitise and mobilise biodiversity data have resulted in the generation of ‘biodiversity big data’, enabling ecological research at scales previously not possible. However, gaps, biases and uncertainties in these data influence analytical outcomes and the validity of scientific research and conservation actions. Here, we estimated tree species inventory completeness globally and identified where future surveys should focus to maximise regional inventories.
Location
Global.
Methods
We analysed spatial patterns in sampling effort of tree species occurrence records from the Global Biodiversity and Information Facility (GBIF) and estimated global tree species inventory completeness for 100 × 100 km grid cells (sampling units) and ecoregions. We also identified forested areas for future botanical exploration, by examining the spatial overlap between inventory completeness, remaining natural habitat and protected areas and degrees of forest modification by anthropogenic pressure (forest integrity).
Results
Spatial patterns in sampling effort and tree species inventory completeness were unevenly distributed around the world. Only 35% of ecoregions and 18% of sampling units can be considered well surveyed, most of which were concentrated in the Global North, including Europe, North America and Australia. Large areas in species‐rich tropical regions, especially in Southeast Asia, remained poorly documented. Moreover, our results showed that many areas with low inventory completeness overlapped with ecoregions retaining less than 50% of natural habitat and protected land area, as well as sampling units with low forest integrity.
Main Conclusions
Due to limitations in biodiversity data, simply sampling more will not necessarily lead to increasing knowledge. We illustrated how gaps in these data can be used to improve existing knowledge by identifying priority areas for future surveys. With ongoing anthropogenic impacts and escalating rates of biodiversity loss, limited resources should be allocated to strategically survey regions likely to yield new knowledge and improve biodiversity representativeness.
... For trees, a separate effort to boost the proportion of species with known extinction risk assessment exists: the Global Tree Assessment (GTA; BGCI, 2021). The GTA aims to assess the conservation status of all tree species following IUCN RL criteria to allow effective prioritization of conservation measures (Newton et al., 2015). As of late 2021, the GTA included, approximately 43,700 species, with about 20% of the known species yet to be assessed or classified (BGCI, 20211). ...
... This importance of trees is one reason why evergreen rainforests have long been at the forefront of conservation effort at the expense of other diverse and unique habitats (Parr et al., 2014;Veldman et al., 2019;Silveira et al., 2021). The ecological and economic importance of trees and their potential as umbrella species are reasons for the concentrated effort and systematic assessment of the GTA in 2015 (Newton et al., 2015). In this study, we complemented this effort with an automated deep learning assessment to approximate extinction risk assessments for all tree species with sufficient distribution data available, within a fraction of the time needed for full assessments on the RL or during GTA. ...
Trees are fundamental for Earth’s biodiversity as primary producers and ecosystem engineers and are responsible for many of nature’s contributions to people. Yet, many tree species at present are threatened with extinction by human activities. Accurate identification of threatened tree species is necessary to quantify the current biodiversity crisis and to prioritize conservation efforts. However, the most comprehensive dataset of tree species extinction risk—the Red List of the International Union for the Conservation of Nature (IUCN RL)—lacks assessments for a substantial number of known tree species. The RL is based on a time-consuming expert-based assessment process, which hampers the inclusion of less-known species and the continued updating of extinction risk assessments. In this study, we used a computational pipeline to approximate RL extinction risk assessments for more than 21,000 tree species (leading to an overall assessment of 89% of all known tree species) using a supervised learning approach trained based on available IUCN RL assessments. We harvested the occurrence data for tree species worldwide from online databases, which we used with other publicly available data to design features characterizing the species’ geographic range, biome and climatic affinities, and exposure to human footprint. We trained deep neural network models to predict their conservation status, based on these features. We estimated 43% of the assessed tree species to be threatened with extinction and found taxonomic and geographic heterogeneities in the distribution of threatened species. The results are consistent with the recent estimates by the Global Tree Assessment initiative, indicating that our approach provides robust and time-efficient approximations of species’ IUCN RL extinction risk assessments.
... The Global Tree Assessment aimed to produce an IUCN Red List conservation assessment for all tree species by the end of 2020 (Newton et al. 2015). This is continuing and major undertaking has succeeded for nearly half of the almost 60 000 described tree species worldwide (Keppel et al. 2021). ...
... However, given the budgetary constraints (Rondinini et al. 2014) and the ongoing loss of tree biodiversity (Crowther et al. 2015), local expert assessments may be the only feasible solutions to achieve IUCN Red List conservation assessments (and subsequent conservation actions) before many species are lost irreversibly. Rapid expert assessments may also be the only way to achieve extremely ambitious targets, such as producing IUCN Red List conservation assessment for some 60 000 species within about 5 years for the Global Trees Assessment (Newton et al. 2015). Nevertheless, expert-based species assessments for the IUCN Red List would be greatly improved, if they clearly stated the main source of information and the confidence the source had in making the assessment. ...
Expert knowledge is widely used for assessing the conservation status of little-known species. Pterocymbium oceanicum is a large, emergent tree endemic to Fiji. Experts classified the species as ‘Critically Endangered’ (IUCN Red List) in 2016 and estimated the population size at <250 mature individuals with the largest subpopulation consisting of a single stand of 100 individuals. We surveyed this stand and counted 133 individuals, which validated the expert estimate. However, we discovered an additional three stands nearby, increasing the total subpopulation size to 433 individuals. Therefore, the expert estimate reliably and conservatively estimated population size but missed important information. Field surveys suggest that P. oceanicum has a narrow ecological niche as a long-lived early pioneer at mid-elevations (400–800 m) in seasonally dry forests, one of Fiji’s most degraded ecosystems. The introduced African Tulip Tree, Spathodea campanulata, is invading the sampled subpopulation and shares the characteristics of being a large, fast-growing and early successional tree. Therefore, the narrow niche of P. oceanicum may now be threatened by S. campanulata. Our study highlights that expert knowledge can provide valuable information about threatened species but also has limitations. IUCN Red List assessments based solely on expert assessments should therefore be cautiously interpreted. The invasion by S. campanulata poses a serious threat to P. oceanicum and needs to be carefully monitored, with the impacts of S. campanulata on the establishment and growth of P. oceanicum requiring urgent investigation.
... Focusing on plants, it is estimated that almost 40% of all vascular plant species and three quarters of undescribed plant species are threatened by extinction (Brown et al., 2023). This loss of plant diversity is often overlooked, despite the fact that it is key to other wildlife diversity (Newton et al., 2015). ...
Without a robust construct, it is currently difficult for researchers to systematically assess and facilitate a societal shift toward greater plant awareness. Using a Delphi study, we take a first step towards such construct by developing a definition and testable dimensions. This paper proposes a first expert validated definition and three distinct dimensions that allow researchers to assess plant awareness and to identify and compare key influences on the construct across different socio‐cultural groups. With this improved framework, research can support initiatives to promote plant awareness in society, a critical step in addressing challenges such as the climate crisis. image
... are not yet included in the IUCN Red List assessment so far (Beech et al., 2017;BGCI, 2022;Gallagher et al., 2023;Humphreys et al., 2019;Newton & Oldfield, 2008). Conservation assessments are not only missing, but they may also be out of date; updates are lacking for over 5000 of the world's tree species, which has prompted the creation of the Global Tree Assessment (Beech et al., 2017;Newton et al., 2015;Rivers et al., 2023). Conservation efforts are particularly important for islands, which may harbor endemic tree species that are extra sensitive to extinction and increasingly vulnerable because of the devastating effects of global warming on insular ecosystems (Barstow et al., 2022;Pouteau & Birnbaum, 2016;Ralimanana et al., 2022). ...
Societal Impact Statement
Conserving frankincense trees (Boswellia) is crucial for both ecological and socio‐economic reasons. Surveying these trees in the field and using remote sensing unmanned aerial vehicles in the Socotra Archipelago, we found that Socotran frankincense trees are threatened by forest fragmentation, overgrazing, and increasingly frequent extreme climate events. A better understanding of the distribution and the threats of these important insular species will improve the conservation policy of the local authorities and benefit local communities in the Socotra Archipelago. At the same time, this work serves as a good practice example to guide conservation efforts for other culturally important threatened tree species around the world, therefore helping to sustain local livelihoods, fostering ecological resilience, and supporting socio‐economic stability.
Summary
Globally, frankincense trees (Burseraceae: Boswellia) are increasingly under threat because of habitat deterioration, climate impacts, and the olibanum trade. Despite harboring nearly half of the species in the genus, up‐to‐date insights are lacking for the insular endemic frankincense trees of the Socotra Archipelago UNESCO (United Nations Educational, Scientific and Cultural Organization) World Heritage Site (Yemen).
We combined georeferencing of individual trees in the field with remote sensing applying unmanned aerial vehicles (UAVs) to evaluate Boswellia distribution and (sub)population sizes in the entire Socotra Archipelago.
We counted 17,253 trees across all 11 taxa and we surveyed almost 55% directly in the field, collecting individual information on threats and health indicators. We estimate that the current total population sizes of the relatively common Socotran Boswellia taxa (Boswellia elongata, Boswellia popoviana, and Boswellia ameero) consist of a few thousand mature individuals with fragmented distribution of which a large proportion occurs in highly disjunct relictual stands, while the more range‐restricted species survive only through a few hundred (Boswellia nana and Boswellia samhaensis) to fewer than a hundred trees (Boswellia scopulorum). Our field data show that the Socotran frankincense trees are threatened by fragmentation and overgrazing resulting in a lack of natural regeneration, in combination with effects of extreme climate events (e.g., higher frequency and intensity of cyclones and prolonged drought) and potential future infrastructure developments; the species are less impacted by resin collection.
We provide recommendations to strategize urgent protection of the declining Socotran frankincense trees, and we update their conservation status, resulting in an endangered status for seven and a critically endangered status for four taxa.
... The conservation status of a given species is a collective assessment based on its current population, ecological range and its probability of survival [39][40][41][42] . Accordingly, the natural and anthropogenic changes in the environment and habitat which are superimposed on the environmental gradients along altitudes have a substantial influence on the conservation status of a given species within an ecosystem. ...
Tropical rainforests in Sri Lanka are biodiversity hotspots, which are sensitive to anthropogenic disturbance and long-term climate change. We assessed the diversity, endemism and conservation status of these rainforests across a wide altitudinal range (100–2200 m above sea level) via a complete census of all trees having ≥ 10 cm diameter at breast height in ten one-hectare permanent sampling plots. The numbers of tree families, genera and species and community-scale tree diversity decreased with increasing altitude. Tree diversity, species richness and total basal area per ha across the altitudinal range were positively associated with long-term means of maximum temperature, annual rainfall and solar irradiance. Percentage of endangered species increased with increasing altitude and was positively associated with cumulative maximum soil water deficit, day-night temperature difference and high anthropogenic disturbance. Percentage of endemic species was greater in the lowland rainforests than in high-altitude montane forests. Nearly 85% of the species were recorded in three or less plots, which indicated substantial altitudinal differentiation in their distributions. Less than 10 individuals were recorded in 41% of the endemic species and 45% of the native species, which underlined the need for urgent conservation efforts across the whole altitudinal range.
... Trees have been a vital resource for human well-being and contribute to meeting the challenges of sustainable growth and development, food security, and prosperity (Turner-Skoff and Cavender 2019). Trees, the ecosystem engineers and foundation organisms in terrestrial ecosystems, play a crucial role in regulating ecological pyramids as well as the dynamics of the Earth's biosphere, by incorporating most of plant and animal species worldwide (Newton et al. 2015;FAO and UNEP 2020). Thus, tree species richness can affect species richness of other flora and fauna (Novotny et al. 2006;Chazdon 2014;Rudel et al. 2016). ...
Trees have evolved as vital elements of terrestrial ecosystems and provide various ecosystem services. The presence of several biodiversity hotspots highlights South Asia as a biodiversity rich with a high degree of endemism. However, little is known about the diversity of native tree species in this region. Here, we summarize the information on the diversity and distributions of native tree species in South Asia. A country-wise inventory of native tree species and their geographical occurrence was compiled across eight South Asian countries using the "Global Tree Search" and "Global Biodiversity Information Facility" database. A total of 3,172 native tree species were recorded in 138 families in the region. We found that > 50% of them belonged to 15 highly diverse families led by Rubiaceae (223 spp), Lauraceae (217 spp) and Leguminosae (164 spp). Syzygium (102 spp), Ficus (81 spp) and Diospyros (74 spp) were the top three genus with high native tree diversity. Although India topped the list with 2,613 species, however, based on the country's per unit land area, Bhutan and Sri Lanka had high tree diversity. India and Sri Lanka were ranked high, with 651 and 382 species of endemic trees. Around 33% of Sri Lanka's native tree diversity was found to be threatened and had a high risk of loss of biodiversity. Two Himalayan neighbours, Bhutan, and Nepal had 50% similarity in their native tree species. Overlaying land cover patterns with native tree distribution revealed that South Asian urban landscapes were mainly dominated by IUCN's least-concern (LC) Red Listed native tree species. This study provides important baseline information on native tree species and advocates to promote the development of appropriate conservation measures for native tree species in South Asia, including their use in urban greening.
... After land use changes, climate change is one of the major threats to the conservation of plant species, along with invasive species and air pollution, affecting the conservation status of many species and stressing an already precarious natural balance (McCarty, 2001;Corlett, 2016). According to the Global Tree Assessment (Newton et al., 2015), which aims to assess the conservation status of all tree species globally (Beech et al., 2017), a third of world's tree species are threatened with extinction. The most endangered species are the endemic ones with restricted habitats, occurring in confined areas, such as small isolated islands or other insular habitats such as mountains (Lavergne et al., 2004;Wulff et al., 2013;Rivers et al., 2022). ...
The Socotra Archipelago (Yemen) is an interesting biodiversity hotspot, with a significant proportion of endemic species that have evolved to survive in an arid subtropical environment, inscribed as a World Heritage Site by UNESCO. The terrestrial ecosystems of Socotra face several threats, including climate change, overgrazing and soil degradation. Socotra Island has four endemic species of the genus Commiphora (Burseraceae). Little is known about their local distribution and ecology, yet these trees could be useful indicator species. Our study focuses on the distribution and niche characterisation of the four endemic Commiphora species of Socotra and how climate change may affect them. The aim is to improve insights into their habitats and to provide an essential basis for future local management plans and ecological restoration. We compared the current distribution with the forecasted potential distribution under a CMIP6 (Coupled Model Intercomparison Project) climate scenario, allowing us to define target conservation areas and assess potential local extinction risks. To achieve this, we collected distribution data in the field throughout Socotra Island, covering the current distribution ranges of the four species. To assess the potential distribution of these species, we applied three models (GAM, MaxEnt, RandomForest) using bioclimatic, topographic and soil variables. Forecasts under a climate change scenario were made using bioclimatic variables from the CMCC-CESM2 climate model for two different socioeconomic pathways. The distribution of three endemic Socotran Commiphora is mainly correlated to clay content in the soil and winter precipitation, while C. socotrana is affected by seasonal precipitation and temperature. Under different potential future climate scenarios, the distribution of C. ornifolia is predicted to remain stable or increase, while C. parvifolia distribution could increase, yet C. planifrons and C. socotrana are predicted to undergo a strong reduction of suitable areas and an upward shift in the mountains. Our results highlight that it is essential to conserve the unique terrestrial ecosystems in Socotra and to preserve these endemic trees which have a wide range of ecosystem services. Updates on the predicted extinction risk assessment are fundamental to understand conservation priorities and strategize future actions to ensure the persistence of Socotran myrrh trees and other endangered endemic tree taxa on the island.
... This emerging trend stemmed from the characterization of the structures of the trees globally and facilitated a change from a more comprehensive understanding of the elementary ecological function units to a better record-keeping method used to track the Earth's carbon cycles [3]. This trend has long been reflected in the field of global tree assessment [34] as well as the relevant disciplines. For example, the complicated links between forest growth and their corresponding normalized difference vegetation indices were investigated on a global scale [35]. ...
Trees are spread worldwide, as the watchmen that experience the intricate ecological effects caused by various environmental factors. In order to better understand such effects, it is preferential to achieve finely and fully mapped global trees and their environments. For this task, aerial and satellite-based remote sensing (RS) methods have been developed. However, a critical branch regarding the apparent forms of trees has significantly fallen behind due to the technical deficiency found within their global-scale surveying methods. Now, terrestrial laser scanning (TLS), a state-of-the-art RS technology, is useful for the in situ three-dimensional (3D) mapping of trees and their environments. Thus, we proposed co-developing an international TLS network as a macroscale ecotechnology to increase the 3D ecological understanding of global trees. First, we generated the system architecture and tested the available RS models to deepen its ground stakes. Then, we verified the ecotechnology regarding the identification of its theoretical feasibility, a review of its technical preparations, and a case testification based on a prototype we designed. Next, we conducted its functional prospects by previewing its scientific and technical potentials and its functional extensibility. Finally, we summarized its technical and scientific challenges, which can be used as the cutting points to promote the improvement of this technology in future studies. Overall, with the implication of establishing a novel cornerstone-sense ecotechnology, the co-development of an international TLS network can revolutionize the 3D ecological understanding of global trees and create new fields of research from 3D global tree structural ecology to 3D macroecology.
... The Global Tree Assessment was established in 2015 to assess the conservation status of the world's 60,000 tree species (Beech et al., 2017;Newton et al., 2015). Papua New Guinea was identified as a priority country for the Global Tree Assessment, given a high rate of endemism and previous low rate of assessment output. ...
Societal Impact Statement
Papua New Guinea has a diverse tree flora. Now for the first time we know that 460 (36%) of its endemic tree species are threatened with extinction in the wild. These trees require immediate conservation action, through a variety of methods. Protection of trees is essential in Papua New Guinea as many people across the country rely on them for their livelihoods. Additionally, the extinction of these species would mean the loss of unique biodiversity. With the majority of forest cover still remaining in Papua New Guinea, it presents an almost unique opportunity to save tree diversity at a large scale and should therefore be at the forefront of the conservation agenda.
Summary
Papua New Guinea is one of the world's most tree diverse countries, with over 1,200 endemic tree species. However, forests within the country face a range of threats but the impact of these threats on individual tree species has yet to be studied. Without identifying which species are threatened, where they are and their major threats it is not possible to effectively prioritise conservation actions for the trees of Papua New Guinea.
The Global Tree Assessment for Papua New Guinea produced International Union for Conservation of Nature (IUCN) Red List assessments for over 90% of tree species endemic to Papua New Guinea. The assessments compiled information on extinction risk, major threats, conservation and research needs for the country's tree flora.
Four hundred and sixty tree species are threatened with extinction, including 143 Critically Endangered species. This is 36% of the country's endemic tree flora. The majority of tree species are threatened by annual‐perennial non‐timber crop farming, logging and establishment of wood and pulp plantations. The change in land use instigated by these threats causes lowland tropical/sub‐tropical forest to be the most threatened habitat types for trees.
To protect Papua New Guinea's diverse tree flora, a range of conservation activities are required. Both in situ and ex situ conservation efforts, which are species specific, are needed and activities should be supported on a local, national and international level with continued and expanded collaboration between international NGOs and botanists and specialists working in Papua New Guinea.
... The Global Tree Assessment is an initiative assessing the conservation status of all the world's known tree species [4][5][6]. It is a collaborative global initiative linking taxonomic, geographical, ecological and conservation information in support of biodiversity conservation policy and action. ...
The interlinked biodiversity crisis and challenge of global climate change cannot be addressed without the management of tree species. It is crucial that we use the information now available as a result of the Global Tree Assessment to manage, conserve and restore threatened tree species and tree diversity. With over 17,500 tree species now known to be threatened with extinction, well-planned actions need to be urgently identified and implemented that target multiple species. In this review, we highlight approaches that coordinate and mobilise multi-species conservation at the taxonomic, national, regional and global levels. Only through a considerable scaling up of planning and action will we prevent the extinction of both trees and the associated plants, animals and fungi that depend on them, sustain livelihoods and ensure the ecological health of the planet.
... It is clear that the global scientific and botanical community is only just establishing the scope of the world's tree diversity and its risk of extinction. To address this challenge, Botanic Gardens Conservation International (BGCI) and the International Union for Conservation of Nature (IUCN) Species Survival Commission Global Tree Specialist Group initiated the Global Tree Assessment project in 2015, which aims to provide threat assessment and prioritization information to inform conservation action for all of the world's $60,000 tree species, to prevent tree species extinction (Newton et al., 2015). ...
Societal Impact Statement
Understanding the current state of trees within the United States is imperative for protecting those species, their habitats, and the countless communities they support, as well as the ecosystem services they provide. We present an updated checklist of all tree species native to the contiguous United States, their state distribution, extinction risk, and most common threats. Knowledge of national threat “hotspots” and conservation priorities facilitates efficient conservation efforts and the allocation of resources to safeguard the 11–16% of US tree species that are threatened. These results lay the groundwork for tree and ecosystem conservation efforts in the United States that contribute to achieving critical international conservation goals, including the United Nations Decade for Ecosystem Restoration and the Global Tree Assessment.
Summary
The Global Tree Assessment aims to complete threat assessments for all the world's ~60,000 tree species, but most species native to the continental United States had either never been assessed or were outdated on the two most widely used threat assessment platforms in the United States, International Union for the Conservation of Nature (IUCN) Red List and NatureServe. There was also no coordinated mechanism for sharing data between these platforms, resulting in missing, duplicated, or outdated information.
We (1) created an updated checklist of all tree species native to the contiguous United States based on the standardized Global Tree Assessment tree definition, (2) created over 700 new or updated IUCN Red List assessments and NatureServe Global Ranks, and (3) developed a replicable assessment data sharing process.
We present an updated checklist of native US trees that includes 881 species from 269 genera, with Quercus and Crataegus as the most species‐rich tree genera. We present the first country‐wide analysis of tree extinction risk, patterns of geographic and taxonomic diversity, and leading threats. An estimated 11–16% of US tree species are threatened with extinction, with the most common threat being invasive and problematic pests and diseases. We introduce a “crosswalk” process for efficient, large‐scale data sharing between the IUCN Red List and NatureServe, using IUCN Red List Species Information Service (SIS) Connect, which can be applied to other taxonomic groups in North America.
The checklist, threat assessments, and crosswalk methodology represent a significant advancement in prioritizing conservation action for at‐risk tree species and restoration of forests in the United States, supporting the global goals of the United Nations Decade for Ecosystem Restoration and the Global Tree Assessment effort.
... A yet unknown number of Mexican endemic and near endemic arborescent species are threatened by land use change and/or climate change, which both are seriously and visibly affecting its biodiversity, and potentially urban and rural livelihoods. The impact of the decline and loss of tree species, the principal components of forest ecosystems which play an important role in the Earth's biogeochemical processes (Millennium Ecosystem Assessment, 2005), are largely understudied because their conservation status has not been comprehensively assessed (Newton et al., 2015). Only a few efforts have been realised in Mexico to comprehensively assess tree conservation statuses, one focusing on a specific habitat, the Red List of Mexican Cloud Forest Trees (González-Espinosa et al., 2011) and three focusing on a taxonomic group, the Magnolia Red List (Rivers et al., 2016) in which 15 Mexican Magnolia species were assessed, the Fraxinus and not threatened, and lacks thousands of seriously threatened species, as the process does not involve a systematic review of all organisms, and instead depends on proposals that are presented upon invitation to the communities of specialists, which are then reviewed by committees of specialists. ...
• Mexico is floristically the fourth most species-rich country in the world. Currently, 3,620 native tree species are reported from this country. Mexico has been a forerunner at global level in recognising the need for plant conservation, yet this is in stark contrast with governmental programs and actions, past and present, that negatively affect(ed) immense areas of primary vegetation. In the framework of the Global Tree Assessment, to date, we have assessed the conservation status of nearly 1,500 Mexican endemic and near endemic tree species for the International Union for the Conservation of Nature (IUCN) Red List, the distribution data of which we use here for a first meta-analysis of conservation statuses and spatial distribution patterns in a newly delimited area we call Natural Mexico.
• Our database consists of 112,416 taxonomically and geographically very carefully curated distribution points of 1,474 tree species endemic to Mexico and adjacent areas, belonging to 98 flowering plant families. The extensive curation methodology we consider essential for both research and conservation purposes is emphasised.
• Nearly 60% of the assessed tree species are threatened, almost double the percentage of threatened arborescent species at global level. Tropical rainforests and cloud forests house the highest proportions of threatened trees.
• These assessments have an extensive impact, as they not only are the starting point of urgent species conservation actions, but also allow for comprehensive studies including extinction risk estimation, gap analyses for conservation planning and species reintroductions, all this in a framework of land use change, climate change and landscape composition and configuration.
... Precise monitoring of the status and trends of forest genetic resources as well as monitoring the quality of forest degradation, forest restoration, and species composition are difficult tasks (Newton et al., 2015). The number of extant tree species in the world has been estimated by (Beech et al., 2017) as about 60,000. ...
Currently, we are at a point of unprecedented changes in the climate, which is affecting the food chain across the agro-biodiversity. The changes in species diversity in the food web indicate the changes in variety at any of the trophic levels. Adaptation with the environmentally changed conditions depends on the effective use of biological components of the local agro-ecosystem, which is also the focal point of sustainable approaches. Sustainable management of natural resources in the agro-biodiversity is essential for food and livelihood security of the living beings in an ecosystem. In this chapter, a synthesis of published evidence of the complex and crucial relationships between elements of agro-biodiversity, climate change, and the food chain is provided. A review of published articles highlights the status and trend of changes in the components of agro-biodiversity, the factors enhancing such changes, and the points needed to be considered to maintain a sustainable way of food production for obtaining a stable food chain. Finally, the present status of studies and researches relating both of the agro-biodiversity and genetic resources are identified. Nevertheless, despite the need for more knowledge of agro-biodiversity and the food chain, it is clear that more effective action would be taken.
... So although we have an estimated 60,000 botanical experts within the BGCI network alone, they are skewed towards the north, and one of our big challenges is how to get that expertise and knowledge and share it with gardens in the south, particularly in the tropics, in order to solve some of these species-related problems. As an example, BGCI is leading the Global Tree Assessment (GTA) (Newton et al., 2015), which aims to assess the conservation status of all the world's 60,000 tree species. We are on track to do that, and already we know that there are more rare tree species than there are common tree species -58 per cent of tree species are endemic to a single country (Beech et al., 2017), and around 40 per cent of tree species are threatened with extinction (Malin Rivers, pers. ...
As many as 40% of the world’s plant species are currently threatened with extinction, and botanic gardens have an important role to play in restoring habitats and supporting plant species recovery in situ. Specialist horticultural skills are essential for proactive plant conservation and management. However, there are a number of impediments to deploying horticultural expertise where it is needed the most, including lack of information about which species and recovery programmes need expertise, where that expertise can be found, and institutional or practical impediments such as availability of time and funding. In this paper, the author presents details on tools and resources developed by Botanic Gardens Conservation International designed to engage and support the participation of horticulturists in plant conservation.
... An additional key resource for tree conser- (e.g., Gillespie et al., 2014). As the Global Tree Assessment, an initiative to assess the IUCN Red List status for all known tree species (Newton et al., 2015), is moving closer to completion, tree data in the IUCN Red List database will become an increasingly representative tool for assessing the conservation status of, and threats to, ...
Aims
Trees dominate the biomass in many ecosystems and are essential for ecosystem functioning and human well‐being. They are also one of the best studied functional groups of plants, with vast amounts of biodiversity data available in scattered sources. We here aim to illustrate that an efficient integration of this data could produce a more holistic understanding of vegetation.
Methods
To assess the extent of potential data integration, we use key databases of plant biodiversity to 1) obtain a list of tree species and their distributions, 2) identify coverage and gaps of different aspects of tree biodiversity data, and 3) discuss large‐scale patterns of tree biodiversity in relation to vegetation.
Results
Our global list of trees included 58,044 species. Taxonomic coverage varies in three key databases, with data on the distribution, functional traits, and molecular sequences for about 84%, 45% and 44% of all tree species, which is > 10% greater than for plants overall. For 28% of all tree species, data are available in all three databases. However, less data are digitally accessible about the demography, ecological interactions, and socio‐economic role of tree species. Integrating and imputing existing tree biodiversity data, mobilization of non‐digitized resources and targeted data collection, especially in tropical countries, could help closing some of the remaining data gaps.
Conclusions
Due to their key ecosystem roles and having large amounts of accessible data, trees are a good model group for understanding vegetation patterns. Indeed, tree biodiversity data are already beginning to elucidate the community dynamics, functional diversity, evolutionary history and ecological interactions of vegetation, with great potential for future applications. An interoperable and openly accessible framework linking various databases would greatly benefit future macroecological studies, and should be linked to a platform that makes information readily accessible to end users in biodiversity conservation and management.
... This critical stage is usually omitted in most assessment studies, although it provides essential information to understand the long-term viability of species. Furthermore, the data provided in this work may serve as a baseline to monitor the population status in the piedmont forest and will allow us to prioritize conservation efforts, which is essential considering the high number of tree species that are potentially at risk of extinction (Newton et al., 2015). ...
The piedmont dry forest of northwestern Argentina has been under intensive and unplanned forest logging focused on 12 tree species, without any attempts having been made to ensure their regeneration or long-term conservation. In this study, we assessed the conservation status of these timber species in the piedmont dry forest of northwestern Argentina and compared our results with the IUCN assessment. We considered an inadequate conservation status if the species: (1) occurred in less than 50% of the sampled plots, (2) had a density of large trees (more than 40 cm DBH) lower than one individual per hectare, or (3) had a density of saplings (more than 30 cm in height and less than 9.9 cm in DBH) lower than 30 in.ividuals per hectare. Our results showed an inadequate conservation status for eight of the 12 studied timber tree species. Additionally, only seven species were previously assessed and categorized on the IUCN Red List, with our categorization agreeing with only four of them. The data provided in this work can serve as a baseline to monitor the population trends of these species; information can also help to prioritize conservation efforts, which is essential considering the high number of tree species that have potential extinction risk in the short-term.
... Assessments were matched to species names in the World Checklist of Vascular Plants (WCVP, 2020) database Geographical biases in assessments were evident, with particular effort focused on African plants (Figure 2a), and a big gap in assessments for plants from both temperate and tropical Asia. Woody perennials were vastly overrepresented by assessments on the Red List, a bias likely to increase with the rapid progress of the Global Tree Assessment (Newton et al., 2015;Rivers, 2017). Species having recorded human use were also overrepresented, their societal importance having prompted assessment (e.g., Davis et al., 2019;Howes et al., 2020). ...
Plant and fungal biodiversity support all life on earth and merit careful stewardship in an increasingly uncertain environment. However, gaps and biases in documented extinction
risks to plant and fungal species impede effective management. Formal extinction risk assessments help avoid extinctions, through engagement, financial or legal mechanisms, but most plant and fungal species lack assessments. Available global assessments cover c. 30% of plant species (ThreatSearch). Red List coverage over-represents woody perennials and useful plants but underrepresents single-country endemics. Fungal assessments overrepresent well-known species and are too few to infer global status or trends. Proportions of assessed vascular plant species considered threatened vary between global assessment datasets: 34% (ThreatSearch), 44% (International Union for Conservation of Nature Red List f Threatened Species). Our predictions, correcting for several quantifiable biases, suggest that 39% of all vascular plant species are threatened with extinction. However, other biases remain unquantified, and may affect our estimate. Preliminary trend data show plants moving toward extinction. Quantitative estimates based on plant extinction risk assessments may understate likely biodiversity loss: they do not fully capture the impacts of climate change, slow-acting threats, or clustering of extinction risk which could amplify loss of evolutionary potential. The importance of extinction risk estimation to support existing and emerging conservation initiatives is likely to grow as threats to biodiversity intensify. This necessitates urgent and strategic expansion of efforts
toward comprehensive and ongoing assessment of plant and fungal extinction risk.
... This report is a contribution to Target 2 of the Global Strategy for Plant Conservation (GSPC) which states that by 2020, there should be 'an assessment of the conservation status of all known plant species, as far as possible, to guide conservation action'. This project also contributes directly to the Global Tree Assessment, an initiative of Botanic Gardens Conservation International (BGCI) and the IUCN/SSC Global Tree Specialist Group (GTSG) to assess the extinction risk all the world's tree species by 2020 (Box 1, Newton et al., 2015;Rivers, 2017). ...
The European Red List is a review of the status of European species according to IUCN regional Red Listing guidelines. It identifies those species that are threatened with extinction at the regional level – in order that appropriate conservation action can be taken to improve their status. This publication summarises results for all Europe’s native species of tree (454 species), of which 265 species (over 58%) are endemic to continental Europe, with 56% (252 species) endemic to the 28 EU Member States. Of these, 168 (42%) of the species are threatened with extinction at the European level, however, for 57 species (nearly 13%) there was insufficient information to assign a conservation status, and are therefore classified as Data Deficient, and in need of further research. The main threat to tree species in Europe has been identified as invasive or problematic species, impacting 38% of tree species, followed by deforestation and wood harvesting, and urban development (both affecting 20% of tree species). For threatened species, livestock farming, land abandonment, changes in forest and woodland management, and other ecosystem modifications such as fire are the major threats, impacting the survival of trees
... This report is a contribution to Target 2 of the Global Strategy for Plant Conservation (GSPC) which states that by 2020, there should be 'an assessment of the conservation status of all known plant species, as far as possible, to guide conservation action'. This project also contributes directly to the Global Tree Assessment, an initiative of Botanic Gardens Conservation International (BGCI) and the IUCN/SSC Global Tree Specialist Group (GTSG) to assess the extinction risk all the world's tree species by 2020 (Box 1, Newton et al., 2015;Rivers, 2017). ...
The European Red List is a review of the status of European species according to IUCN regional Red Listing guidelines. It identifies those species that are threatened with extinction at the regional level – in order that appropriate conservation action can be taken to improve their status. This publication summarises results for all Europe’s native species of tree (454 species), of which 265 species (over 58%) are endemic to continental Europe, with 56% (252 species) endemic to the 28 EU Member States. Of these, 168 (42%) of the species are threatened with extinction at the European level, however, for 57 species (nearly 13%) there was insufficient information to assign a conservation status, and are therefore classified as Data Deficient, and in need of further research. The main threat to tree species in Europe has been identified as invasive or problematic species, impacting 38% of tree species, followed by deforestation and wood harvesting, and urban development (both affecting 20% of tree species). For threatened species, livestock farming, land abandonment, changes in forest and woodland management, and other ecosystem modifications such as fire are the major threats, impacting the survival of trees
... In order to assess the risk of extinction for trees and monitor progress, the Global Tree Assessment was launched in 2015. The Global Tree Assessment aims to have a conservation assessment for every known tree species by the year 2020 (Newton et al. 2015;Rivers 2017). The Global Tree Assessment will be used to inform, prioritise, monitor and manage tree species diversity on a global, regional and/or national level. ...
The GlobalTreeSearch database provides the names of all tree species known to science and the countries where these trees grow. TreeeX is a visual exploration system that supports multifaceted analyses of the GlobalTreeSearch data. Investigating research questions on biodiversity and conservation on a global or national scale are visually supported by interactive choropleth maps that color countries according to frequency, diversity or uniqueness of prevalent tree species. By combining the GlobalTreeSearch and ThreatSearch data sets, additional information on the conservation status of trees can be visualized globally and nationally through TreeeX. Similarities and differences in tree diversity, endemism and conservation status to other countries can be analyzed in detail. Several examples outline the system’s capability of delivering insights concerning the geographical diversity of tree species.
... This report is a contribution to Target 2 of the Global Strategy for Plant Conservation (GSPC) which states that by 2020, there should be 'an assessment of the conservation status of all known plant species, as far as possible, to guide conservation action'. This project also contributes directly to the Global Tree Assessment, an initiative of Botanic Gardens Conservation International (BGCI) and the IUCN/SSC Global Tree Specialist Group (GTSG) to assess the extinction risk all the world's tree species by 2020 (Box 1, Newton et al., 2015;Rivers, 2017). ...
... The database was not perfect at first but it is getting better with every iteration, thanks to an army of reviewers and supporters from all over the world that has arisen because we put the list out there. It can already be used to generate national checklists, lists of endemics and lists of threatened trees for every country in the world, and it is being used as the basis for the Global Tree Assessment (Newton et al., 2015). The next step is to produce distribution maps for every species, based on all available knowledge, and this will hugely increase the utility of this tool. ...
Societal Impact Statement
Plants are fundamental to solving many of humanity's most important challenges: food insecurity, water scarcity, energy, health, and climate change. With more than 20% of the world's plant species currently threatened with extinction, the loss of plant diversity will result in reduced options for human innovation, adaptation, and resilience. The world's botanic gardens already conserve and manage around a third of all known plant species in their living collections as well as seed banks as an insurance policy against extinction and as a resource to support scientific research. This work needs to be expanded rapidly if we are to avoid further plant species extinctions.
Summary
Historically, botanic garden science has been dominated by the disciplines of economic botany and taxonomy. Today, with around 20% of plant species threatened with extinction, the author argues that unless botanic gardens shift their efforts toward the conservation, management and use of plants, the loss of plant diversity will stifle human innovation, adaptation, and resilience. The enormous body of taxonomic knowledge, skills, data, and collections built up over the past two centuries is fundamental to managing plant diversity. These resources need to be used to address challenges such as food insecurity, water scarcity, renewable energy, human health, biodiversity conservation, and climate change. At a time when botanic gardens are increasingly seen as visitor attractions, rather than scientific institutions, refocusing their efforts is in the best interests of botanic gardens as well as those of broader society. The author gives examples of how botanic gardens are already supplying crop wild relatives to plant breeders; using their living collections to assess resilience to climate change and vulnerability to pests and diseases; and conserving rare and threatened plant species for future use. However, in spite of these efforts, only a small fraction of the estimated 60,000 plant scientists and specialist horticulturists in the world's botanic gardens are engaged in scientific research that has demonstrable impact on how we conserve or manage plant diversity. The author argues that it is time for botanic gardens to develop a new contract with society—a contract that delivers outcomes for society that only botanic gardens, as custodians of the world's plant diversity, can deliver.
... level (Kelly, 1976). An IUCN initiative, the global tree assessment hopes to provide an estimate of the conservation status of trees globally through a process of taxonomic authentication, distribution mapping, population assessment, and red list categorisation (Newton et al., 2015). While forests were part of initial conservation efforts, domestication of forest trees is in its infancy compared to many crop species (Campbell et al., 2003), with the exception of some fruit trees. ...
Trees are a charismatic group of plants bound together by life form rather than taxonomy, as the tree form occurs across most phylogenetic lineages of plants. Trees resist a rigorous definition but can broadly be defined as having secondary thickening (wood), large stature, and great longevity. This article focuses on angiosperms and addresses salient issues in the evolution of trees and highlights the current conservation practices. Although the tree form has arisen on multiple instances, evidence suggests a common origin of the woody habit. Parallel evolution and reversals in woody traits have obscured this origin; however, recent molecular evidence suggests a common origin of lignocellulosic genes involved in the production of wood. Trees tend to have high levels of heterozygosity, nevertheless a consensus has not been reached on the evolutionary potential of trees to withstand climate change and a more thorough understanding of phenotypic plasticity is essential to predict their response to short-and medium-term climate change. Approximately 1% of global tree species have been genetically characterised to some extent. Direct measurement or use of indicators and proxies is needed to get a more comprehensive indication of global forest genetic resources. As large, long-lived organisms, a dynamic or close-to-nature in situ conservation approach, which facilitates evolution, is the most efficient option and best practice for tree conservation.
... Another benefit of our compilation is that it can be used as a prioritisation tool. Work continues to broaden the taxonomic scope of the global red list through initiatives such as the Biodiversity Barometer (Stuart et al. 2010) and the Global Tree Assessment (Newton et al. 2015;Rivers 2017), and our list can be used to prioritise potentially threatened taxa for full IUCN Red List assessment and publication on the IUCN Red List. To achieve this one can query ThreatSearch for species assessed as threatened or possibly threatened and make these priorities for full global IUCN assessments. ...
The Global Strategy for Plant Conservation (GSPC) set an ambitious target to achieve a conservation assessment for all known plant species by 2020. We consolidated digitally available plant conservation assessments and reconciled their scientific names and assessment status to predefined standards to provide a quantitative measure of progress toward this target. The 241,919 plant conservation assessments generated represent 111,824 accepted land plant species (vascular plants and bryophytes, not algae). At least 73,081 and up to 90,321 species have been assessed at the global scale, representing 21-26% of known plant species. Of these plant species, at least 27,148 and up to 32,542 are threatened. Eighty plant families, including some of the largest, such as Asteraceae, Orchidaceae, and Rubiaceae, are underassessed and should be the focus of assessment effort if the GSPC target is to be met by 2020. Our data set is accessible online (ThreatSearch) and is a baseline that can be used to directly support other GSPC targets and plant conservation action. Although around one-quarter of a million plant assessments have been compiled, the majority of plants are still unassessed. The challenge now is to build on this progress and redouble efforts to document conservation status of unassessed plants to better inform conservation decisions and conserve the most threatened species.
... Organized by BGCI and the International Union for Conservation of Nature (IUCN) Species Survival Commission's Global Tree Specialist Group, its goal is to complete the assessment by 2020. The Global Tree Assessment will be a major challenge, requiring the international coordination of numerous organizations and individuals, and a comprehensive list of the world's tree species along with their country-level distributions, GlobalTreeSearch (Beech et al. 2017), but success will improve targeting of conservation resources to tree species at greatest risk; improve the design of forest conservation, restoration and management efforts; and strengthen capacity for sustainable forest management and land planning (Newton et al. 2015). ...
Genetic diversity provides the essential basis for the adaptation and resilience of tree species to environmental stress and change. The genetic conservation of tree species is an urgent global necessity as forest conversion and fragmentation continue apace, damaging insects and pathogens are transported between continents, and climate change alters local habitat suitability. Effective and efficient genetic conservation of tree species presents a substantial challenge because of the lack of basic information about many species, inadequate resources, and a historical lack of coordination within and between conservation sectors. Several cooperative efforts are already under way and are achieving conservation success, but much work remains. The Gene Conservation of Tree Species—Banking on the Future workshop in 2016 enabled the exchange of information and the creation of collaborations among tree conservation stakeholders. Several key themes emerged during the meeting’s presentations and dialogue, which are further explored in this paper. In situ conservation of species is the long-term goal and is often the most efficient approach for preserving the genetic diversity of many forest tree species. Whether existing reserves adequately protect species and are sufficient for future conservation needs is uncertain. Ex situ conservation is an important complement to in situ efforts, acting as an insurance measure against extinction, providing material for restoration, enabling additional research opportunities, and educating the public. Networks of botanic gardens, government agencies, and non-governmental organizations must continue to coordinate ex situ and in situ efforts to improve the efficiency and effectiveness of tree conservation efforts. Assessing and prioritizing which species and populations require genetic conservation and prioritizing among them is a critical need. Two key tree restoration needs are for wider dissemination of planting stock, particularly stock with resistance to insects and pathogens, and for specific silvicultural prescriptions that facilitate restoration efforts. Effective genetic conservation of forest trees will require ongoing cooperation among widely diverse groups of scientists, managers, and policymakers from the public and private sectors.
... Mapping species is also an important step in assessing the conservation status of all of the world's tree species, an activity essential to ensure effective conservation and management of tree diversity. This is the aim of the Global Tree Assessment-a complete assessment of the conservation status of all trees by 2020 (Newton et al., 2015). The Global Tree Assessment is being made possible by the GlobalTreeSearch database, which will be used to prioritize species in need of conservation assessment. ...
This paper presents, for the first time, an overview of all known tree species by scientific name and country level distribution, and describes an online database—GlobalTreeSearch—that provides access to this information. Based on our comprehensive analysis of published data sources and expert input, the number of tree species currently known to science is 60,065, representing 20 percent of all angiosperm and gymnosperm plant species. Nearly half of all tree species (45%) are found in just ten families, with the three most tree-rich families being Leguminosae, Rubiaceae, and Myrtaceae. Geographically, Brazil, Colombia, and Indonesia are the countries with the most tree species. The countries with the most country-endemic tree species reflect broader plant diversity trends (Brazil, Australia, China) or islands where isolation has resulted in speciation (Madagascar, Papua New Guinea, Indonesia). Nearly 58 percent of all tree species are single country-endemics. Our intention is for GlobalTreeSearch to be used as a tool for monitoring and managing tree species diversity, forests, and carbon stocks on a global, regional, and/or national level. It will also be used as the basis of the Global Tree Assessment, which aims to assess the conservation status of all of the world’s tree species by 2020.
Understanding plant extinctions is crucial for effective conservation planning because they pose risks to other organisms, ecosystems, and human well-being. In the present study, we highlighted plant species that are likely to be extinct by analyzing all plant species categorized by the IUCN Red List as Critically Endangered with “Possibly Extinct” tags (CR (PE)). Our aims are to provide data on i) plant species likely extinct, ii) their distribution across regions, ii) threats to these species, and iv) their protection. After screening for rediscovery, synonymization with extant taxa, and presence in ex-situ collections, we recorded a total of 474 species categorized as CR (PE). The majority (93.25%) of the species were assigned to the CR (PE) category using criterion B of the IUCN Red List Criteria, which is primarily based on the species’ geographic range. The plant family with the highest number of likely extinct species was Lauraceae with 74 species. These likely extinct species were mostly trees reported to be found in the tropics, including islands. The most prominent threat that placed plant species into the CR (PE) category was habitat degradation and conversion. Clear understanding of extinction status is crucial for effective conservation planning. Therefore, comprehensive assessments, including targeted surveys and probabilistic modeling, should be carried out. This will help determine which species are genuinely CR rather than Extinct (EX), ensuring that conservation actions, when implemented, are truly impactful.
This study looks into the interactions between environmental conditions and climate change, as well as their combined effects on plant and vegetation development patterns in ecologically sensitive areas. We investigate how temperature, precipitation, and atmospheric CO2 levels affect vegetation dynamics in a variety of ecosystems by combining data from satellite imagery, ground-based observations, and climate models. Our findings underscore these regions’ susceptibility to climate-induced stresses, with considerable changes in species distribution, phenology, and productivity. The study emphasizes the importance of adaptive management strategies to mitigate adverse effects and enhance the resilience of these critical ecosystems. This research contributes to a deeper understanding of the complex interactions between climate variables and ecological responses, providing a foundation for informed conservation and policy-making efforts in the face of global climate change.
Biodiversity is declining globally, yet many biodiversity hotspots still lack comprehensive species conservation assessments. Using multiple International Union for Conservation of Nature (IUCN) Red List criteria to evaluate extinction risks and millions of herbarium and forest inventory records, we present automated conservation assessments for all tree species of the Atlantic Forest biodiversity hotspot, including ~1100 heretofore unassessed species. About 65% of all species and 82% of endemic species are classified as threatened. We rediscovered five species classified as Extinct on the IUCN Red List and identified 13 endemics as possibly extinct. Uncertainties in species information had little influence on the assessments, but using fewer Red List criteria severely underestimated threat levels. We suggest that the conservation status of tropical forests worldwide is worse than previously reported.
The allelochemical para-hydroxybenzoic acid (pHBA) is a serious threat to poplars subjected to continuous cropping. In order to elucidate the responsive mechanisms of plants to pHBA stress, we here performed tandem mass tag-based quantitative proteomic analysis combined with physiological, transcriptional, and metabolic analyses by using H2O2 treatment as a positive control. H2O2 and O2•− levels and the activities of several antioxidant enzymes increased under pHBA stress. In total, 289 differentially expressed proteins were identified in the 84 K poplar leaves under pHBA stress; among them, 161 and 128 proteins were upregulated and downregulated, respectively. The pHBA-responsive protein analysis showed that the antioxidant system, signal transduction, carbohydrate metabolism, biosynthesis of secondary metabolites, gene expression regulation, and many other biological processes were altered in poplars to cope with this stress. Overall, this study provides a new insight for the molecular mechanisms underlying pHBA stress in plants and may have potential application values in poplar genetic breeding for overcoming continuous cropping obstacles.
Trees play vital roles in many of the world's ecosystems while providing many benefits to people. New evidence indicates that a third of tree species are threatened with extinction, representing a tree extinction crisis. Here we demonstrate how tree species extinction will lead to the loss of many other plants and animals and significantly alter the world's ecosystems. We also show how tree extinction will negatively affect billions of people through loss of livelihoods and benefits. We highlight a series of urgent actions needed to avert an ecological, cultural and socioeconomic catastrophe caused by widespread extinction of tree species. Summary Trees are of exceptional ecological importance, playing a major functional role in the world's ecosystems, while also supporting many other plants, animals and fungi. Many tree species are also of direct value to people, providing a wide range of socioeconomic benefits. Loss of tree diversity could lead to abrupt declines in biodiversity, ecosystem functions and services and ultimately ecosystem collapse. Here we provide an overview of the current knowledge regarding the number of tree species that are threatened with extinction, and the threats that affect them, based on results of the Global Tree Assessment. This evidence suggests that a third of the world's tree species are currently threatened with extinction, which represents a major ecological crisis. We then examine the potential implications of tree extinctions, in terms of the functioning of the biosphere and impacts on human well-being. Large-scale extinction of tree species will lead to major biodiversity losses in other species groups and substantially alter the cycling of carbon, water and nutrients in the world's ecosystems. Tree extinction will also undermine the livelihoods of the billions of people who currently depend on trees and the benefits they provide. This warning to humanity aims to raise awareness of the tree extinction crisis, which is a major environmental issue that requires urgent global attention. We also identify some priority actions that need to be taken to reduce the extinction risk of tree species and to avert the ecological and socioeconomic catastrophe that will result from large-scale extinction of tree species.
Societal Impact Statement
Trees play vital roles in many of the world's ecosystems while providing many benefits to people. New evidence indicates that a third of tree species are threatened with extinction, representing a tree extinction crisis. Here we demonstrate how tree species extinction will lead to the loss of many other plants and animals and significantly alter the world's ecosystems. We also show how tree extinction will negatively affect billions of people through loss of livelihoods and benefits. We highlight a series of urgent actions needed to avert an ecological, cultural and socio‐economic catastrophe caused by widespread extinction of tree species.
Summary
Trees are of exceptional ecological importance, playing a major functional role in the world's ecosystems, while also supporting many other plants, animals and fungi. Many tree species are also of direct value to people, providing a wide range of socio‐economic benefits. Loss of tree diversity could lead to abrupt declines in biodiversity, ecosystem functions and services and ultimately ecosystem collapse. Here we provide an overview of the current knowledge regarding the number of tree species that are threatened with extinction, and the threats that affect them, based on results of the Global Tree Assessment. This evidence suggests that a third of the world's tree species are currently threatened with extinction, which represents a major ecological crisis. We then examine the potential implications of tree extinctions, in terms of the functioning of the biosphere and impacts on human well‐being. Large‐scale extinction of tree species will lead to major biodiversity losses in other species groups and substantially alter the cycling of carbon, water and nutrients in the world's ecosystems. Tree extinction will also undermine the livelihoods of the billions of people who currently depend on trees and the benefits they provide. This warning to humanity aims to raise awareness of the tree extinction crisis, which is a major environmental issue that requires urgent global attention. We also identify some priority actions that need to be taken to reduce the extinction risk of tree species and to avert the ecological and socio‐economic catastrophe that will result from large‐scale extinction of tree species.
Human life and other biotic organisms inhabiting Earth are endangered due to the vagaries of climate change, overexploitation and unsustainable use of natural resources like freshwater ecosystems, forests, genetic resources, wildlife and land use, etc. While emphasizing on the vitality of natural ecosystems and the goods and services accruing from them for human and other biotic organisms, focus is also reinforced on the conservation and sustainable use of natural resources to ward off adverse impacts of climate change and sustain the continuity of life cycle on Earth.
Botanic gardens and arboreta offer the opportunity to conserve and manage a wide range of plant diversity ex situ, and in situ in the broader landscape. The rationale that botanic gardens have a major role to play in preventing plant species extinctions is based on the assumptions that (1) there is no technical reason why any plant species should become extinct, and (2) that, as a professional community, botanic gardens possess a unique set of skills that encompass finding, identifying, collecting, conserving and growing plant diversity across the entire taxonomic spectrum. Botanic Gardens Conservation International (BGCI) is the pivotal centre of a global network of c. 2,600 botanic gardens and arboreta, which includes living collections representing at least one-third of known plant diversity; world class seed banks, glasshouses and tissue culture infrastructures; and technical knowledge networks covering all aspects of plant conservation. Following the example of the crop conservation community, BGCI is promoting the concept of a cost-effective, rational,botanic garden-centred Global System for the conservation and management of plant diversity.This system will aim to collect, conserve, characterise and cultivate samples from all of the world’s rare and threatened plants as an insurance policy against their extinction in the wild and as a source of plant material for human innovation, adaptation and resilience.
Only a green world, rich in plants, can sustain us and the millions of other species with which we share this planet. But, in an era of global change, nature is on the retreat. Like the communities they form, many plant species are becoming rarer, threatened even to the point of extinction. The worldwide community of almost three thousand botanic gardens are holders of the most diverse living collections of plants and have the unique potential to conserve plant diversity. Conservation biology is a fast moving and often controversial field, and, as the contributions within these pages from experts in the field demonstrate, plant conservation is multifaceted, mirroring the complexity of the biodiversity it aims to protect, and striving not just to protect threatened plants but to preserve ecosystem services and secure the integrity of the biosphere.
This article reviews the status of plant diversity in the Anthropocene. It considers what is known about the number of species in different plant groups and the geographical distribution of plant diversity. Plants are vitally important in the provision of ecosystem goods and services, and their major values are summarized. As with other components of biodiversity, plant species are threatened by human activities. Knowledge of threatened plant species is discussed. Two major international Conventions aim to protect threatened plant species. One of these, the Convention on Biological Diversity, has agreed targets for plant conservation. Progress in the conservation of plant diversity is briefly reviewed against these targets.
While there is vigorous debate on whether the Anthropocene epoch began in 1800, as originally proposed, less attention has been paid to the transition from Stage 2 of the existing three stage chronology, in which carbon dioxide emissions accelerated after 1945, to Stage 3, in which after 2015 acceleration is expected to reach criticality, and the Earth System is predicted to pass through an irreversible “tipping point” to a warmer state, unless this is averted by a new planetary stewardship. This paper critically evaluates this chronology and finds (a) that there is insufficient evidence for an imminent irreversible tipping point, and (b) that the international community established a new planetary stewardship in 1992 when it agreed on new conventions on climate change and biodiversity in response to three decades of warnings about global environmental problems. The paper proposes an alternative framework for conceptualizing the transition between Stages 2 and 3 of the Anthropocene. This generates the hypothesis that after the actual carbon dioxide concentration of the atmosphere has exceeded a critical threshold level, some biophysical processes will change at rates proportional to the difference between the carbon dioxide concentration of the atmosphere and the threshold level, and to the rate of climate change. Evidence is presented which suggests that this new reversible tipping point could have been passed before 1980, when enhanced forest growth was first observed in mature forests in Amazonia. Modelling simulations suggest that this temporal relativity effect could soon be joined by a spatio-temporal relativity effect, as species become committed to extinction and/or form new species assemblages in the 21st Century when climate zones shift. Since this new tipping point is reversible there is still time for planetary stewardship to become more effective and minimize the harmful effects of climate change.
Knowledge products comprise assessments of authoritative information supported by standards , governance, quality control, data, tools, and capacity building mechanisms.
Can we save the charismatic megaflora? - Volume 49 Issue 3 - Peter Crane
The IUCN Red List of Threatened Species uses geographical distribution as a key criterion in assessing the conservation status of species. Accurate knowledge of a species’ distribution is therefore essential to ensure the correct categorization is applied. Here we compare the geographical distribution of 35 species of chameleons endemic to East Africa, using data from the Global Biodiversity Information Facility (GBIF) and data compiled by a taxonomic expert. Data screening showed 99.9% of GBIF records used outdated taxonomy and 20% had no locality coordinates. Conversely the expert dataset used 100% up-to-date taxonomy and only seven records (3%) had no coordinates. Both datasets were used to generate range maps for each species, which were then used in preliminary Red List categorization. There was disparity in the categories of 10 species, with eight being assigned a lower threat category based on GBIF data compared with expert data, and the other two assigned a higher category. Our results suggest that before conducting desktop assessments of the threatened status of species, aggregated museum locality data should be vetted against current taxonomy and localities should be verified. We conclude that available online databases are not an adequate substitute for taxonomic experts in assessing the threatened status of species and that Red List assessments may be compromised unless this extra step of verification is carried out.
Forests in Flux
Forests worldwide are in a state of flux, with accelerating losses in some regions and gains in others. Hansen et al. (p. 850 ) examined global Landsat data at a 30-meter spatial resolution to characterize forest extent, loss, and gain from 2000 to 2012. Globally, 2.3 million square kilometers of forest were lost during the 12-year study period and 0.8 million square kilometers of new forest were gained. The tropics exhibited both the greatest losses and the greatest gains (through regrowth and plantation), with losses outstripping gains.
The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional
scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire
Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest
that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are
habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that
a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree
community.
The impacts of growing human populations and economies are both rapidly and directly transforming forests in many areas. However, little known are the pervasive effects of the ongoing climatic changes on the condition and status of forests around the world. Global patterns are now evident with the global tree mortality that is now above its usual mortality levels as it is affected by drought and heat-related forest stress and dieback. Thus, the possibility of an increased risk of climate-induced dieback is now being considered within many of the forests and woodlands of today. A focus will be given on the climatic water stress that is driven by both drought and warm temperatures. However, studying the trends in forest mortality and predictions has its limitations with such a number of information gaps and scientific uncertainties. First is the absence of an adequate global data on forest health status, followed by the fact that only a few tree species have the researchers an adequate quantitative knowledge with regards to its physiological thresholds of individual tree mortality from chronic or acute water stress. Lastly, the adequate knowledge of the feedback and non-linear interactions between climate-induced forest stress and other climate-related disturbance processes are lacking among the current scientists.
Tropical forests are being subjected to a wide array of disturbances in addition to outright deforestation. Selective logging is one of the most common disturbances ongoing in the Amazon, which results in significant changes in forest structure and canopy integrity. Assessing forest canopy fractional cover (fc) is one way of measuring forest degradation caused by selective logging. In this study we applied a linear mixture model to a vegetation index domain to map canopy fractional cover in tropical forests in the Amazonian state of Mato Grosso, Brazil. The modified soil adjusted vegetation index (MSAVI) was selected as the optimal vegetation index in the model because it is most linearly related to green canopy abundance up to leaf area index = 4.0. In the canopy fc map derived from the Landsat Enhanced Thematic Mapper Plus (ETM+) image, the fc distribution ranged from 0 to 0.4 in clear-cut areas, higher than 0.8 in undisturbed forests, and a wider range of 0.3-1.0 in degraded forests. The fc map was validated with the 1-m panchromatic sharpened IKONOS image. In the logged forests the ETM+ estimated fc values were clustered along the 1:1 line in the scatterplot with the IKONOS estimated fc and had a squared correlation coefficient (R2) of 0.8.
Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive
assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
The loss of large old trees in many ecosystems around the world poses a threat to ecosystem integrity.
The Amazon basin is likely to be increasingly affected by environmental changes: higher temperatures, changes in precipitation, CO2 fertilization and habitat fragmentation. To examine the important ecological and biogeochemical consequences of these changes, we are developing an international network, RAINFOR, which aims to monitor forest biomass and dynamics across Amazonia in a co-ordinated fashion in order to understand their relationship to soil and climate. The network will focus on sample plots established by independent researchers, some providing data extending back several decades. We will also conduct rapid transect studies of poorly monitored regions. Field expeditions analysed local soil and plant properties in the first phase (2001–2002). Initial results suggest that the network has the potential to reveal much information on the continental-scale relations between forest and environment. The network will also serve as a forum for discussion between researchers, with the aim of standardising sampling techniques and methodologies that will enable Amazonian forests to be monitored in a coherent manner in the coming decades.
Biodiversity research and conservation efforts in the tropics are hindered by the lack of knowledge of the assemblages found there, with many species undescribed or poorly known. Our initiative, the Tree Biodiversity Network (BIOTREE-NET), aims to address this problem by assembling georeferenced data from a wide range of sources, making these data easily accessible and easily queried, and promoting data sharing. The database (GIVD ID NA-00-002) currently comprises ca. 50,000 tree records of ca. 5,000 species (230 in the IUCN Red List) from >2,000 forest plots in 11 countries. The focus is on trees because of their pivotal role in tropical forest ecosystems (which contain most of the world's biodiversity) in terms of ecosystem function, carbon storage and effects on other species. BIOTREE-NET currently focuses on southern Mexico and Central America, but we aim to expand coverage to other parts of tropical America. The database is relational, comprising 12 linked data tables. We summarise its structure and contents. Key tables contain data on forest plots (including size, location and date(s) sampled), individual trees (including diameter, when available, and both recorded and standardised species name), species (including biological traits of each species) and the researchers who collected the data. Many types of queries are facilitated and species distribution modelling is enabled. Examining the data in BIOTREE-NET to date, we found an uneven distribution of data in space and across biomes, reflecting the general state of knowledge of the tropics. More than 90% of the data were collected since 1990 and plot size varies widely, but with most less than one hectare in size. A wide range of minimum sizes is used to define a 'tree'. The database helps to identify gaps that need filling by further data collection and collation. The data can be publicly accessed through a web application at http://portal.biotreenet.com. Researchers are invited and encouraged to contribute data to BIOTREE-NET.
GeoCAT is an open source, browser based tool that performs rapid geospatial analysis to ease the process of Red Listing taxa. Developed to utilise spatially referenced primary occurrence data, the analysis focuses on two aspects of the geographic range of a taxon: the extent of occurrence (EOO) and the area of occupancy (AOO). These metrics form part of the IUCN Red List categories and criteria and have often proved challenging to obtain in an accurate, consistent and repeatable way. Within a familiar Google Maps environment, GeoCAT users can quickly and easily combine data from multiple sources such as GBIF, Flickr and Scratchpads as well as user generated occurrence data. Analysis is done with the click of a button and is visualised instantly, providing an indication of the Red List threat rating, subject to meeting the full requirements of the criteria. Outputs including the results, data and parameters used for analysis are stored in a GeoCAT file that can be easily reloaded or shared with collaborators. GeoCAT is a first step toward automating the data handling process of Red List assessing and provides a valuable hub from which further developments and enhancements can be spawned.
In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the
rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of
the state of biodiversity (covering species’ population trends, extinction risk, habitat extent and condition, and community
composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity
(including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts)
showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected
areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate
of biodiversity loss does not appear to be slowing.
Reducing Emissions from Deforestation (REDD) aims to curb carbon emissions from deforestation by financially compensating forest owners. However, compensation based on the opportunity costs of REDD might underestimate true costs by failing to account for downstream economic values of current land uses, including employment and wealth generated by processing and service industries. A comprehensive analysis of REDD impacts should also include sociopolitical impacts. REDD might exclude people from forest land, causing demographic shifts, and the declining tax revenues from commodity production and associated industries might be a disincentive to government investment in forested regions to the detriment of forest communities and regional development. We argue for the need to recognize and appropriately compensate the full range of economic, social and political net costs of REDD.
Biome-scaledisturbancesbyeruptiveherbivoresprovidevaluableinsightsintospeciesinteractions,ecosystemfunction,andimpactsof globalchange. We present a conceptual framework using one system as a model, emphasizing interactions across levels of biological hierarchy and spatiotemporal scales. Bark beetles are major natural disturbance agents in western North American forests. However, recent bark beetle population eruptions have exceeded the frequencies, impacts, and ranges documented during the previous 125 years. Extensive host abundance and susceptibility, concentrated beetle density, favorable weather, optimal symbiotic associations, and escape from natural enemies must occur jointly for beetles to surpass a series of thresholds and exert widespread disturbance. Opposing feedbacks determine qualitatively distinct outcomes at junctures at the biochemical through landscape levels. Eruptions occur when key thresholds are surpassed, prior constraints cease to exert influence, and positive feedbacks amplify across scales. These dynamics are bidirectional, as landscape features influence how lower-scale processes are amplified or buffered. Climate change and reduced habitat heterogeneity increase the likelihood that key thresholds will be exceeded, and may cause fundamental regime shifts. Systems in which endogenous feedbacks can dominate after external forces foster the initial breach of thresholds appear particularly sensitive to anthropogenic perturbations.
On 11 January 2010, the United Nations inaugurated the International Year of Biodiversity in Berlin. This initiative is timely,
because the environmental movement suffers from an imbalance between its sense of urgency and its intensity of activity. Center
stage is now occupied by concerns for the physical environment—in particular, climate change, pollution, and depletion of
nonrenewable resources. However, if the living world is to be kept in anything approaching a sustainable condition that can
adapt to changes, then politicians, government officials, scientists, and the public will need to give biodiversity the urgent
attention that they are starting to give to the physical environment.
The services of ecological systems and the natural capital stocks that produce them are critical to the functioning of the Earth's life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent part of the total economic value of the planet. We have estimated the current economic value of 17 ecosystem services for 18 biomes, based on published studies and a few original calculations. For the entire biosphere, the value (most of which in outside the market) in estimated to be in the range of US33 trillion per year. Because of the nature of the uncertainties, thin must be considered a minimum estimate. Global gross national product total is around US$18 trillion per year.
The authors describe how we are harnessing the power of web 2.0 technologies to create new approaches to collecting, mapping, and sharing geocoded data. The authors begin with GMapCreator that lets users fashion new maps using Google Maps as a base. The authors then describe MapTube that enables users to archive maps and demonstrate how it can be used in a variety of contexts to share map information, to put existing maps into a form that can be shared, and to create new maps from the bottom-up using a combination of crowdcasting, crowdsourcing, and traditional broadcasting. The authors conclude by arguing that such tools are helping to define a neogeography that is essentially ‘‘mapping for the masses,’’ while noting that there are many issues of quality, accuracy, copyright, and trust that will influence the impact of these tools on map-based communication.
Estimates of the number, and preferably the identity, of species that will be threatened by land-use change and habitat loss are an invaluable tool for setting conservation priorities. Here, we use collections data and ecoregion maps to generate spatially explicit distributions for more than 40,000 vascular plant species from the Amazon basin (representing more than 80% of the estimated Amazonian plant diversity). Using the distribution maps, we then estimate the rates of habitat loss and associated extinction probabilities due to land-use changes as modeled under 2 disturbance scenarios. We predict that by 2050, human land-use practices will have reduced the habitat available to Amazonian plant species by approximately 12-24%, resulting in 5-9% of species becoming "committed to extinction," significantly fewer than other recent estimates. Contrary to previous studies, we find that the primary determinant of habitat loss and extinction risk is not the size of a species' range, but rather its location. The resulting extinction risk estimates are a valuable conservation tool because they indicate not only the total percentage of Amazonian plant species threatened with extinction but also the degree to which individual species and habitats will be affected by current and future land-use changes.
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon
sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background
(noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years
among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest
density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases
in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely
to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases
in tree mortality rates.
Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive
assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
The first global assessment of amphibians provides new context for the well-publicized phenomenon of amphibian declines. Amphibians
are more threatened and are declining more rapidly than either birds or mammals. Although many declines are due to habitat
loss and overutilization, other, unidentified processes threaten 48% of rapidly declining species and are driving species
most quickly to extinction. Declines are nonrandom in terms of species' ecological preferences, geographic ranges, and taxonomic
associations and are most prevalent among Neotropical montane, stream-associated species. The lack of conservation remedies
for these poorly understood declines means that hundreds of amphibian species now face extinction.
Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200000 to 422000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the world's major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates.
Future drought is projected to occur under warmer temperature conditions as climate change progresses, referred to here as global-change-type drought, yet quantitative assessments of the triggers and potential extent of drought-induced vegetation die-off remain pivotal uncertainties in assessing climate-change impacts. Of particular concern is regional-scale mortality of overstory trees, which rapidly alters ecosystem type, associated ecosystem properties, and land surface conditions for decades. Here, we quantify regional-scale vegetation die-off across southwestern North American woodlands in 2002-2003 in response to drought and associated bark beetle infestations. At an intensively studied site within the region, we quantified that after 15 months of depleted soil water content, >90% of the dominant, overstory tree species (Pinus edulis, a piñon) died. The die-off was reflected in changes in a remotely sensed index of vegetation greenness (Normalized Difference Vegetation Index), not only at the intensively studied site but also across the region, extending over 12,000 km² or more; aerial and field surveys confirmed the general extent of the die-off. Notably, the recent drought was warmer than the previous subcontinental drought of the 1950s. The limited, available observations suggest that die-off from the recent drought was more extensive than that from the previous drought, extending into wetter sites within the tree species' distribution. Our results quantify a trigger leading to rapid, drought-induced die-off of overstory woody plants at subcontinental scale and highlight the potential for such die-off to be more severe and extensive for future global-change-type drought under warmer conditions.
• tree mortality
• vegetation dynamics
• climate change impacts
• woodlands
• Pinus edulis
Despite recent progress in understanding mechanisms of tree species coexistence in tropical forests, a simple explanation
for the even more extensive diversity of insects feeding on these plants has been missing. We compared folivorous insects
from temperate and tropical trees to test the hypothesis that herbivore species coexistence in more diverse communities could
reflect narrow host specificity relative to less diverse communities. Temperate and tropical tree species of comparable phylogenetic
distribution supported similar numbers of folivorous insect species, 29.0 ± 2.2 and 23.5 ± 1.8 per 100 square meters of foliage,
respectively. Host specificity did not differ significantly between community samples, indicating that food resources are
not more finely partitioned among folivorous insects in tropical than in temperate forests. These findings suggest that the
latitudinal gradient in insect species richness could be a direct function of plant diversity, which increased sevenfold from
our temperate to tropical study sites.
A large carbon sink in northern land surfaces inferred from global carbon cycle inversion models led to concerns during Kyoto Protocol negotiations that countries might be able to avoid efforts to reduce fossil fuel emissions by claiming large sinks in their managed forests. The greenhouse gas balance of Canada's managed forest is strongly affected by naturally occurring fire with high interannual variability in the area burned and by cyclical insect outbreaks. Taking these stochastic future disturbances into account, we used the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to project that the managed forests of Canada could be a source of between 30 and 245 Mt CO2e yr⁻¹ during the first Kyoto Protocol commitment period (2008–2012). The recent transition from sink to source is the result of large insect outbreaks. The wide range in the predicted greenhouse gas balance (215 Mt CO2e yr⁻¹) is equivalent to nearly 30% of Canada's emissions in 2005. The increasing impact of natural disturbances, the two major insect outbreaks, and the Kyoto Protocol accounting rules all contributed to Canada's decision not to elect forest management. In Canada, future efforts to influence the carbon balance through forest management could be overwhelmed by natural disturbances. Similar circumstances may arise elsewhere if global change increases natural disturbance rates. Future climate mitigation agreements that do not account for and protect against the impacts of natural disturbances, for example, by accounting for forest management benefits relative to baselines, will fail to encourage changes in forest management aimed at mitigating climate change.
• greenhouse gases
• factoring out
• mitigation options
• forest management
• Kyoto Protocol
Simulations with the Hadley Centre general circulation model (HadCM3), including carbon cycle model and forced by a ‘business-as-usual’ emissions scenario, predict a rapid loss of Amazonian rainforest from the middle of this century onwards. The robustness of this projection to both uncertainty in physical climate drivers and the formulation of the land surface scheme is investigated. We analyse how the modelled vegetation cover in Amazonia responds to (i) uncertainty in the parameters specified in the atmosphere component of HadCM3 and their associated influence on predicted surface climate. We then enhance the land surface description and (ii) implement a multilayer canopy light interception model and compare with the simple ‘big-leaf’ approach used in the original simulations. Finally, (iii) we investigate the effect of changing the method of simulating vegetation dynamics from an area-based model (TRIFFID) to a more complex size- and age-structured approximation of an individual-based model (ecosystem demography).
We find that the loss of Amazonian rainforest is robust across the climate uncertainty explored by perturbed physics simulations covering a wide range of global climate sensitivity. The introduction of the refined light interception model leads to an increase in simulated gross plant carbon uptake for the present day, but, with altered respiration, the net effect is a decrease in net primary productivity. However, this does not significantly affect the carbon loss from vegetation and soil as a consequence of future simulated depletion in soil moisture; the Amazon forest is still lost. The introduction of the more sophisticated dynamic vegetation model reduces but does not halt the rate of forest dieback. The potential for human-induced climate change to trigger the loss of Amazon rainforest appears robust within the context of the uncertainties explored in this paper. Some further uncertainties should be explored, particularly with respect to the representation of rooting depth.
Recent climate talks in Bali have made progress toward action on deforestation and forest degradation in developing countries, within the anticipated post-Kyoto emissions reduction agreements. As a result of such action, many forests will be better protected, but some land-use change will be displaced to other locations. The demonstration phase launched at Bali offers an opportunity to examine potential outcomes for biodiversity and ecosystem services. Research will be needed into selection of priority areas for reducing emissions from deforestation and forest degradation to deliver multiple benefits, on-the-ground methods to best ensure these benefits, and minimization of displaced land-use change into nontarget countries and ecosystems, including through revised conservation investments.
South Africa has the world's richest temperate flora, with 20,456 indigenous vascular plant taxa recorded. With the current estimate of the global flora at 379,881 taxa, 5% of the world's plant diversity is represented within South African borders. Between 2004 and 2008, South African botanists completed a comprehensive assessment of the status of the South African flora using the International Union for Conservation of Nature and Natural Resources (IUCN) Red List categories and criteria, version 3.1. South Africa is the first floristically megadiverse country to fully assess the status of its entire flora and to achieve Target 2 of the Global Strategy for Plant Conservation (GSPC): "[all assessment of the conservation status of all known plant species, as far as possible, to guide conservation action." Herein, we discuss the critical success factors that allowed an assessment of such a megadiverse flora within five years. Establishing a centralized team of ecologists to develop Red Lists, collaborating with a wide range of botanical experts, streamlining the assessment process via automation, and establishing a data management system that served local conservation needs were crucial to the success of the project. Utilizing the IUCN categories and criteria proved to be, and is suggested as, the most cost-effective measure for other megadiverse countries wanting to achieve Target 2. Quantitative assessments can be done with minimal data, and comprehensive assessments of all known taxa ensure conservation attention for a greater proportion of a flora. The example of South Africa demonstrates that conservation assessments can be done relatively cheaply in developing megadiverse countries (less than $30 per taxon for South Africa). As megadiverse countries have high numbers of endemic plant taxa, it is well worth the investment by IUCN and conservation donors to support continued and future assessment projects.
The IUCN (International Union for Conservation of Nature) Red List of Threatened Species™ (RL) is widely recognised as an authoritative assessment of the conservation status of species, yet its coverage is uneven and incomplete. Trees account for approximately 20% of taxa currently included, but most of these were listed a decade ago. Over the last 10 yr, only 879 taxa have been added to the RL database, representing 11% of the number listed in 1998. However, progress has not been as limited as these data suggest. Ten recent assessments of different groups of trees are profiled, and the lessons learned from these assessments are summarised. In total, these assessments have evaluated >2500 tree taxa, but only a fraction of these have been added to the RL database, raising concerns about the process of data management. Results indicated that a mean of 42% taxa were classified as threatened. Information on the status and distribution of most tree species is severely lacking, a situation compounded by taxonomic confusion in many groups. As a result, RL assessments will continue to be highly dependent on expert knowledge originating from herbarium data, which, as demonstrated here, tends to result in a relatively high proportion of taxa being listed under RL Criteria B1 and B2. Given this situation, attempts to use the RL to support global monitoring of biodiversity appear premature, and much greater support needs to be given to collection of primary field data and expert knowledge to accurately ascertain the current status of the world's threatened tree species.
Over the past few decades, tropical timber production in many Asia–Pacific countries has been akin to the symmetric logistic distribution curve, or ‘Hubbert Curve’, observed in the exploitation of many non-renewable resources—a rapid increase in production followed by a peak and then decline. There are three principal reasons why logging of native tropical forests resembles the mining of a non-renewable resource: the standard cutting cycle of 30–40 years is too brief to allow the wood volume to regenerate; tropical logging catalyses considerable deforestation; and the bulk of logging is undertaken by multinational corporations with little interest in long-term local sustainability. Unless something fundamental changes, we believe tropical forests will continue to be overharvested and cleared apace, leading to an inevitable global decline in tropical timbers of non-plantation origin. It has become common these days to speak of ‘peak oil’. In the tropics, we suggest that we should also begin to discuss the implications of ‘peak timber’.
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The realized species richness of tropical forests cannot yet be reliably mapped at a regional scale due to lack of systematically collected data. An estimate of the potential species richness (PSR), however, can be produced through the use of species distribution modelling. PSR is interpretable as a climatically determined upper limit to observed species richness. We mapped current PSR and future PSR under climate change scenarios for Mesoamerica by combining the spatial distributions of 2000 tree species as predicted by generalized additive models built from herbaria records and climate layers. An explanatory regression tree was used to extract conditional rules describing the relationship between PSR and climate. The results were summarized by country, ecoregion and protected area status in order to investigate current and possible future variability in PSR in the context of regional biodiversity conservation. Length of the dry season was found to be the key determinant of PSR. Protected areas were found to have higher median PSR values than unprotected areas in most of the countries within the study area. Areas with exceptionally high PSR, however, remain unprotected throughout the region. Neither changes in realized species richness nor extinctions will necessarily follow changes in modelled PSR under climate change. However model output suggests that an increase in temperature of around 3°C, combined with a 20 percent decrease in rainfall could lead to a widespread reduction of around 15 percent of current PSR, with values of up to 40 percent in some moist lower montane tropical forests. The modelled PSR of dry forest ecoregions was found to be relatively stable. Some cooler upper montane forests in northern Mesoamerica, where few species of tropical origin are currently found, may gain PSR if species are free to migrate.
Aim We explore the utility of newly available optical and microwave remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and QuikSCAT (QSCAT) instruments for species distribution modelling at regional to continental scales. Using eight Neotropical species from three taxonomic groups, we assess the extent to which remote sensing data can improve predictions of their geographic distributions. For two bird species, we investigate the specific contributions of different types of remote sensing variables to the predictions and model accuracy at the regional scale, where the benefits of the MODIS and QSCAT satellite data are expected to be most significant.
Location South America, with a focus on the tropical and subtropical Andes and the Amazon Basin.
Methods Potential geographic distributions of eight species, namely two birds, two mammals and four trees, were modelled with the maxent algorithm at 1‐km resolution over the South American continent using climatic and remote sensing data separately and combined. For each species and model scenario, we assess model performance by testing the agreement between observed and simulated distributions across all thresholds and, in the case of the two focal bird species, at selected thresholds.
Results Quantitative performance tests showed that models built with remote sensing and climatic layers in isolation performed well in predicting species distributions, suggesting that each of these data sets contains useful information. However, predictions created with a combination of remote sensing and climatic layers generally resulted in the best model performance across the three taxonomic groups. In Ecuador, the inclusion of remote sensing data was critical in resolving the known geographically isolated populations of the two focal bird species along the steep Amazonian–Andean elevational gradients. Within remote sensing subsets, microwave‐based data were more important than optical data in the predictions of the two bird species.
Main conclusions Our results suggest that the newly available remote sensing data (MODIS and QSCAT) have considerable utility in modelling the contemporary geographical distributions of species at both regional and continental scales and in predicting range shifts as a result of large‐scale land‐use change.
The IUCN (International Union for Conservation of Nature) Red List is widely recognised as an authoritative assessment of the conservation status of species. However, the data available for Red Listing are often lacking or uncertain. This paper presents a Bayesian network that may be used to perform a Red List assessment of a taxon using uncertain data. In such cases, input variables can be entered as likelihoods, and the appropriate Red List category is identified by the network using Bayesian inference. Relative performance of the Bayesian network was evaluated by comparison with an alternative method (RAMAS® Red List), based on the use of fuzzy numbers. While results were generally comparable, some differences were noted for species with uncertain input data. Contrasting results may be attributed to differences in how uncertain data are analysed by the two approaches. The Bayesian network has the advantage of being more transparent, facilitating sensitivity analysis. The method consequently has potential for facilitating Red List assessments, particularly for poorly known taxa.
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.
Global knowledge about the spatial distribution of species is orders of magnitude coarser in resolution than other geographically-structured environmental datasets such as topography or land cover. Yet such knowledge is crucial in deciphering ecological and evolutionary processes and in managing global change. In this review, we propose a conceptual and cyber-infrastructure framework for refining species distributional knowledge that is novel in its ability to mobilize and integrate diverse types of data such that their collective strengths overcome individual weaknesses. The ultimate aim is a public, online, quality-vetted 'Map of Life' that for every species integrates and visualizes available distributional knowledge, while also facilitating user feedback and dynamic biodiversity analyses. First milestones toward such an infrastructure have now been implemented.
EcologyParaecologists—locals trained to do the nuts and bolts of ecology research—are an example of excellent science on a shoestring. By hiring and training locally, scientists can boost productivity and cut costs, all while supporting conservation. Over the past 2 decades, paraecologists have discovered thousands of species and churned out hundreds of peer-reviewed articles. Although most paraecologists start with little science knowledge, some have gone on to earn advanced degrees and take key positions in national forest management and conservation. But paraecologists may be a vanishing breed; money woes are threatening the concept of local, long-term hiring for field research.
* Craig Simons is a writer in Beijing.
A globally consistent methodology using satellite imagery was implemented to quantify gross forest cover loss (GFCL) from 2000 to 2005 and to compare GFCL among biomes, continents, and countries. GFCL is defined as the area of forest cover removed because of any disturbance, including both natural and human-induced causes. GFCL was estimated to be 1,011,000 km(2) from 2000 to 2005, representing 3.1% (0.6% per year) of the year 2000 estimated total forest area of 32,688,000 km(2). The boreal biome experienced the largest area of GFCL, followed by the humid tropical, dry tropical, and temperate biomes. GFCL expressed as the proportion of year 2000 forest cover was highest in the boreal biome and lowest in the humid tropics. Among continents, North America had the largest total area and largest proportion of year 2000 GFCL. At national scales, Brazil experienced the largest area of GFCL over the study period, 165,000 km(2), followed by Canada at 160,000 km(2). Of the countries with >1,000,000 km(2) of forest cover, the United States exhibited the greatest proportional GFCL and the Democratic Republic of Congo the least. Our results illustrate a pervasive global GFCL dynamic. However, GFCL represents only one component of net change, and the processes driving GFCL and rates of recovery from GFCL differ regionally. For example, the majority of estimated GFCL for the boreal biome is due to a naturally induced fire dynamic. To fully characterize global forest change dynamics, remote sensing efforts must extend beyond estimating GFCL to identify proximate causes of forest cover loss and to estimate recovery rates from GFCL.
"Part I reviews progress at the regional level. This section was developed from six regional reports prepared for discussion in 2006. Part II presents selected issues in the forest sector, addressing the latest developments in 18 topics of interest to forestry."
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species was increasingly used during the 1980s to assess the conservation status of species for policy and planning purposes. This use stimulated the development of a new set of quantitative criteria for listing species in the categories of threat: critically endangered, endangered, and vulnerable. These criteria, which were intended to be applicable to all species except microorganisms, were part of a broader system for classifying threatened species and were fully implemented by IUCN in 2000. The system and the criteria have been widely used by conservation practitioners and scientists and now underpin one indicator being used to assess the Convention on Biological Diversity 2010 biodiversity target. We describe the process and the technical background to the IUCN Red List system. The criteria refer to fundamental biological processes underlying population decline and extinction. But given major differences between species, the threatening processes affecting them, and the paucity of knowledge relating to most species, the IUCN system had to be both broad and flexible to be applicable to the majority of described species. The system was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size. A species is assigned to a threat category if it meets the quantitative threshold for at least one criterion. The criteria and the accompanying rules and guidelines used by IUCN are intended to increase the consistency, transparency, and validity of its categorization system, but it necessitates some compromises that affect the applicability of the system and the species lists that result. In particular, choices were made over the assessment of uncertainty, poorly known species, depleted species, population decline, restricted ranges, and rarity; all of these affect the way red lists should be viewed and used. Processes related to priority setting and the development of national red lists need to take account of some assumptions in the formulation of the criteria.
Resumen: La Lista Roja de Especies Amenazadas de la UICN (Unión Internacional para la Conservación de la Naturaleza) fue muy utilizada durante la década de l980 para evaluar el estatus de conservación de especies para fines políticos y de planificación. Este uso estimuló el desarrollo de un conjunto nuevo de criterios cuantitativos para enlistar especies en las categorías de amenaza: en peligro crítico, en peligro y vulnerable. Estos criterios, que se pretendía fueran aplicables a todas las especies excepto microorganismos, eran parte de un sistema general para clasificar especies amenazadas y fueron implementadas completamente por la UICN en 2000. El sistema y los criterios han sido ampliamente utilizados por practicantes y científicos de la conservación y actualmente apuntalan un indicador utilizado para evaluar el objetivo al 2010 de la Convención de Diversidad Biológica. Describimos el proceso y el respaldo técnico del sistema de la Lista Roja de la IUCN. Los criterios se refieren a los procesos biológicos fundamentales que subyacen en la declinación y extinción de una población. Pero, debido a diferencias mayores entre especies, los procesos de amenaza que los afectan y la escasez de conocimiento sobre la mayoría de las especies, el sistema de la UICN tenía que ser amplio y flexible para ser aplicable a la mayoría de las especies descritas. El sistema fue diseñado para medir los síntomas del riesgo de extinción, y utiliza cinco criterios independientes que relacionan aspectos de la pérdida poblacional y la declinación del rango de distribución. Una especie es asignada a una categoría de amenaza si cumple el umbral cuantitativo por lo menos para un criterio. Los criterios, las reglas acompañantes y las directrices utilizadas por la UICN tienen la intención de incrementar la consistencia, transparencia y validez de su sistema de clasificación, pero requiere algunos compromisos que afectan la aplicabilidad del sistema y las listas de especies que resultan. En particular, se hicieron selecciones por encima de la evaluación de incertidumbre, especies poco conocidas, especies disminuidas, declinación poblacional, rangos restringidos y rareza; todas estas afectan la forma en que las listas rojas deberían ser vistas y usadas. Los procesos relacionados con la definición de prioridades y el desarrollo de las listas rojas nacionales necesitan considerar algunos de los supuestos en la formulación de los criterios.
Tracking biodiversity change is increasingly important in sustaining ecosystems and ultimately human well-being.
Governments have set the ambitious target of reducing biodiversity loss by the year 2010. The scientific community now faces the challenge of assessing the progress made towards this target and beyond. Here, we review current monitoring efforts and propose a global biodiversity monitoring network to complement and enhance these efforts. The network would develop a global sampling programme for indicator taxa (we suggest birds and vascular plants) and would integrate regional sampling programmes for taxa that are locally relevant to the monitoring of biodiversity change. The network would also promote the development of comparable maps of global land cover at regular time intervals. The extent and condition of specific habitat types, such as wetlands and coral reefs, would be monitored based on regional programmes. The data would then be integrated with other environmental and socioeconomic indicators to design responses to reduce biodiversity loss.
The IUCN Red List of Threatened Species is the most comprehensive resource detailing the global conservation status of plants and animals. The 2004 edition represents a milestone in the four-decade long history of the Red List, including the first Global Amphibian Assessment and a near doubling in assessed species since 2000. Moreover, the Red List assessment process itself has developed substantially over the past decade, extending the value of the Red List far beyond the assignation of threat status. We highlight here how the Red List, in conjunction with the comprehensive data compiled to support it and in spite of several important limitations, has become an increasingly powerful tool for conservation planning, management, monitoring and decision making.