Plant Conservation in the Future: New Challenges, New Opportunities

Throughout the world, plant diversity is being reduced rapidly by the extinction of species and of local differentiated populations. In presenting possible solutions to this very serious problem Ⅰ will first briefly describe the factors that have led to the development of China's wealth of biodivenity; then examine the causes of extinction,with an emphasis on the situation in China; and conclude with recommendations on how to most effectively conserve plants in this huge and botanically diverse country.     

关于IUCN和WWF联合植物保护研究计划工作的成就和今后的任务

植物是人类和动物生活所必需,由于缺乏长远规划的目标,无计划的滥用已导致许多植物灭绝或陷入濒临灭绝的境地。为此,IUCN—WWF联合建立了“植物保护研究计划”,并把其列入他们各自工作的重点。主要工作内容有下列各项:1)传播信息宣传群众;2)建立必要的植物保护的工作条件:3)植物遗传资源的保护:4)野生经济植物的保护:5)加强植物园开展植物保护的工作条件:6)促进植物丰富的国家开展植物保护工作。     

Plant Conservation in the Caribbean Island Biodiversity Hotspot

While the Caribbean is a recognized “biodiversity hotspot”, plant conservation has not received adequate attention; particularly, given the high levels of endemism in many plant groups. Besides establishing protected areas, there needs to be a sustained effort to study the taxonomy, systematics and ecology of the flora. Recent phylogenetic studies have shown high levels of endemism and conservation studies indicate a large propotion of the flora is threatened with extinction. Eight recommendations are given for plant conservation in the region.     

Near Situ Conservation for Wild Plant Species with Extremely Small Populations

Minimum Viable Population (MVP) is the endangered species faced with extinction need prior conservation. A new method of “near situ conservation” has being particularly raised by the Forestry Department of Yunnan Province for conserving Plant Species with Extremely Small Population (PSESP) in China. In accordance with the practices and results of near situ conservation for PSESP and after our study on comparison for growth and adaptation of some state emphasized plant species between near situ and ex situ conservation in recent years, the authors hold that near situ conservation for the plant species faced with extremely high risk of extinction in the wild is more efficient than that of their ex situ conservation. We therefore suggest that the system of near situ conservation need to be constructed as soon as possible, and the high risk extinction mechanism for PSESP need to be urgently studied for selecting the effective conservation methods and adopting scientific measures. Meanwhile, for near situ conservation practices of PSESP, the principles of similarities of climates, habitats and communities must be followed for reducing the investment and raising the conservation effectiveness.     

Comparing strategies to preserve evolutionary diversity

The likely future extinction of various species will result in a decline of two quantities: species richness and phylogenetic diversity (PD, or ‘evolutionary history’). Under a simple stochastic model of extinction, we can estimate the expected loss of these quantities under two conservation strategies: An ‘egalitarian’ approach, which reduces the extinction risk of all species, and a ‘targeted’ approach that concentrates conservation effort on the most endangered taxa. For two such strategies that are constrained to experience the same expected loss of species richness, we ask which strategy results in a greater expected loss of PD. Using mathematical analysis and simulation, we describe how the strategy (egalitarian versus targeted) that minimizes the expected loss of PD depends on the distribution of endangered status across the tips of the tree, and the interaction of this status with the branch lengths. For a particular data set consisting of a phylogenetic tree of 62 lemur species, with extinction risks estimated from the IUCN ‘Red List’, we show that both strategies are virtually equivalent, though randomizing these extinction risks across the tip taxa can cause either strategy to outperform the other. In the second part of the paper, we describe an algorithm to determine how extreme the loss of PD for a given decline in species richness can be. We illustrate the use of this algorithm on the lemur tree.     

Temporal genetic analysis of the endangered tidewater goby: extinction–colonization dynamics or drift in isolation?

Extinction and colonization dynamics are critical to understanding the evolution and conservation of metapopulations. However, traditional field studies of extinction–colonization are potentially fraught with detection bias and have rarely been validated. Here, we provide a comparison of molecular and field‐based approaches for assessment of the extinction–colonization dynamics of tidewater goby (Eucyclogobius newberryi) in northern California. Our analysis of temporal genetic variation across 14 northern California tidewater goby populations failed to recover genetic change expected with extinction–colonization cycles. Similarly, analysis of site occupancy data from field studies (94 sites) indicated that extinction and colonization are very infrequent for our study populations. Comparison of the approaches indicated field data were subject to imperfect detection, and falsely implied extinction–colonization cycles in several instances. For northern California populations of tidewater goby, we interpret the strong genetic differentiation between populations and high degree of within‐site temporal stability as consistent with a model of drift in the absence of migration, at least over the past 20–30 years. Our findings show that tidewater goby exhibit different population structures across their geographic range (extinction–colonization dynamics in the south vs. drift in isolation in the north). For northern populations, natural dispersal is too infrequent to be considered a viable approach for recolonizing extirpated populations, suggesting that species recovery will likely depend on artificial translocation in this region. More broadly, this work illustrates that temporal genetic analysis can be used in combination with field data to strengthen inference of extinction–colonization dynamics or as a stand‐alone tool when field data are lacking.     

极小种群野生植物的近地保护

低于最小存活种群（Minimum Viable Population,简称：MVP）界线而濒临灭绝的极小种群野生植物是需要最优先保护的物种。“近地保护”是云南省林业厅在近年提出的对极小种群野生植物进行保护的一种新方法,它已成为国家林业局的野生植物六大拯救措施之一。根据近年来云南省对极小种群野生植物近地保护的实践和所取得的成果,以及经笔者对若干种国家重点保护植物在迁地保护与就地保护条件下的生长与适应性的比较研究,认为对包括极小种群在内的受严重威胁植物的近地保护的有效性远高于对它们的迁地保护。因而,笔者建议,应该尽快建立和完善野生植物近地保护体系,进一步加强极小种群野生植物高风险灭绝机制的研究,才能有的放矢地选择恰当的保护方法和科学的措施,以及在近地保护的实践中还必须遵循气候相似、生境相似和群落相似的生态学原则,以减少投入和提高其保护的有效性。     

Translocation of Otostegia bucharica,a highly threatened narrowly distributed relict shrub

Translocation is a recognized means of rescuing imperiled species but the evidence for the long-term success of translocations is limited. We report the successful translocation of reproductive individuals of a critically endangered shrub Otostegia bucharica from a site facing imminent habitat destruction into a nearby natural population of the species. The relocated plants were visited the year after planting and 13 years later to assess short-and long-term plant survival. Significant percentage of plants that survived transplanting shock and very dry spring following transplanting(around 36%), and further decrease of this number in the next 12 years by only 14%, indicated that O. bucharica is amenable to translocation using reproductive plants. Based on results of species distribution modeling, and failed attempts of ex situ cultivation, we propose introduction of this species into areas with suitable climatic and soil conditions.However, because there is currently no nature reserve in Uzbekistan having suitable conditions for the species under the present climate and that expected in the near future, and because all known habitats of O. bucharica are exposed to the very strong anthropogenic pressure, establishment of a new protected area, awareness building and involvement of local community in conservation activities are required to prevent extinction of this extremely rare species.     

Invasive alien plant control: The priority to save one of the most rapidly declining island-endemic plant species worldwide

Up to 6,800 plant species endemic to oceanic islands are highly threatened with extinction. Although habitat destruction and fragmentation have greatly contributed to this, it is generally recognised that invasive alien species currently pose the single most important threat to island plants. Most studies exploring the role of novel interspecific interactions in driving declines of island plants, focus on threats mediated by animals, be it direct (e.g. browsing, seed predation, mutualism disruption) or indirect (e.g. extinction of seed dispersal or pollination mutualists). Relatively few studies have investigated the specific role of plant-plant interactions, particularly in-situ. We studied a threatened island endemic plant in rapid decline to evaluate the short (1–2 years) and medium-term (about 1–2 decades) influence of invasive alien plants (IAPs) on individuals and a variety of proxies of plant fitness. We compared mortality of traceable individuals that were recorded 12–20 years previously between habitats that are invaded with IAPs and habitats where IAPs are absent, or have been removed decades ago. We also carried out an in-situ manipulative experiment using 14 randomly chosen plants from around which IAPs were removed, paired with controls, at two sites. Canopy cover change before and after IAPs’ removal was quantified along with above ground biomass of IAPs removed for use as potential explanatory variables of change in proxies of plant fitness. Ten branches were randomly selected per plant and branch dynamics, leaves’ sizes and reproductive structure production were monitored quarterly for two years. Over the medium term, plant mortality was recorded only in presence of IAPs (X² = 4.80, df = 1, p < 0.05). Over the short term, at the plant level, IAPs’ removal triggered overall weak to moderate improvements in the number of surviving and new branches as well as change in number of branches at one of the sites. At the leaf and branch levels, we found weak evidence for positive effects of IAPs removal on surviving leaves, flower buds produced and difference in leaf surface area per branch in one site. We therefore provide some experimental evidence of negative effects of alien plants on overall fitness of the threatened species in-situ presumably through competitive interactions. We posit that these effects were found to be weak to moderate due to the short experimental period over which they could develop (1–2 years). Overall, IAPs stand out as the most severe threat from among all documented threats to the species, for being the only one capable of causing mortality of adult plants. Results hence highlight island plants’ vulnerability to IAPs, and how their timely control would improve the survival and fitness of threatened plants, even at the scale of single individuals. Such a strategy could be more often employed. Our study stresses on prioritising IAPs’ control for rescuing long-lived threatened plants that grow in habitats invaded by alien plants (itself a very common situation on oceanic islands) before addressing other subtler, slower-acting threats, like disrupted pollination or seed dispersal mutualisms, florivory or seed predation.     

30% land conservation and climate action reduces tropical extinction risk by more than 50%

Limiting climate change to less than 2°C is the focus of international policy under the climate convention (UNFCCC), and is essential to preventing extinctions, a focus of the Convention on Biological Diversity (CBD). The post-2020 biodiversity framework drafted by the CBD proposes conserving 30% of both land and oceans by 2030. However, the combined impact on extinction risk of species from limiting climate change and increasing the extent of protected and conserved areas has not been assessed. Here we create conservation spatial plans to minimize extinction risk in the tropics using data on 289 219 species and modeling two future greenhouse gas concentration pathways (RCP2.6 and 8.5) while varying the extent of terrestrial protected land and conserved areas from <17% to 50%. We find that limiting climate change to 2°C and conserving 30% of terrestrial area could more than halve aggregate extinction risk compared with uncontrolled climate change and no increase in conserved area.     

Global distribution and drivers of language extinction risk

Many of the world''s languages face serious risk of extinction. Efforts to prevent this cultural loss are severely constrained by a poor understanding of the geographical patterns and drivers of extinction risk. We quantify the global distribution of language extinction risk—represented by small range and speaker population sizes and rapid declines in the number of speakers—and identify the underlying environmental and socioeconomic drivers. We show that both small range and speaker population sizes are associated with rapid declines in speaker numbers, causing 25% of existing languages to be threatened based on criteria used for species. Language range and population sizes are small in tropical and arctic regions, particularly in areas with high rainfall, high topographic heterogeneity and/or rapidly growing human populations. By contrast, recent speaker declines have mainly occurred at high latitudes and are strongly linked to high economic growth. Threatened languages are numerous in the tropics, the Himalayas and northwestern North America. These results indicate that small-population languages remaining in economically developed regions are seriously threatened by continued speaker declines. However, risks of future language losses are especially high in the tropics and in the Himalayas, as these regions harbour many small-population languages and are undergoing rapid economic growth.     

Long-term differences in extinction risk among the seven forms of rarity

Rarity is widely used to predict the vulnerability of species to extinction. Species can be rare in markedly different ways, but the relative impacts of these different forms of rarity on extinction risk are poorly known and cannot be determined through observations of species that are not yet extinct. The fossil record provides a valuable archive with which we can directly determine which aspects of rarity lead to the greatest risk. Previous palaeontological analyses confirm that rarity is associated with extinction risk, but the relative contributions of different types of rarity to extinction risk remain unknown because their impacts have never been examined simultaneously. Here, we analyse a global database of fossil marine animals spanning the past 500 million years, examining differential extinction with respect to multiple rarity types within each geological stage. We observe systematic differences in extinction risk over time among marine genera classified according to their rarity. Geographic range played a primary role in determining extinction, and habitat breadth a secondary role, whereas local abundance had little effect. These results suggest that current reductions in geographic range size will lead to pronounced increases in long-term extinction risk even if local populations are relatively large at present.     

Survey for threatened plants in riparian fragmented forests: A case study on three Vatica (Dipterocarpaceae) species in Kapuas Hulu,West Kalimantan

Forest fragmentation potentially increases the extinction risk of plant species. Conservation and effective management of threatened plants in fragmented forests require basic information on their population status. In the present study, we conduct population surveys and provide the most current population status of one Endangered (Vatica rynchocarpa) and two Critically Endangered (Vatica havilandii and Vatica cauliflora) species of Vatica in fragmented riparian forests of Kapuas Hulu, West Kalimantan, Indonesia. Using a focused survey method, we assessed populations of the target species in 13 locations with a total covered distance of c. 26 km. We located 317 individuals of V. rynchocarpa and 568 individuals of V. havilandii of which 31 (10.8 %) and 10 (1.8 %) are mature individuals, respectively. In Kapuas Hulu, the endemic tree V.cauliflora were 191 individuals with only 29 (17.9 %) being in a mature stage. All the individuals were found in an unprotected and relatively flat riparian forest with an elevation range of 30–52 m above sea level. We observed that habitat conversion into rubber (Hevea brasiliensis) and the medicinal plant kratom (Mitragyna speciosa) plantations are the main threat to the species. Further studies are needed in order to understand the effects of land use changes and other factors such as river discharge patters on the survival and population dynamic of the species. In addition, protection of the forest fragments is required to conserve all the target species.     

The changing fates of the world's mammals

A recent complete assessment of the conservation status of 5487 mammal species demonstrated that at least one-fifth are at risk of extinction in the wild. We retrospectively identified genuine changes in extinction risk for mammals between 1996 and 2008 to calculate changes in the International Union for Conservation of Nature (IUCN) Red List Index (RLI). Species-level trends in the conservation status of mammalian diversity reveal that extinction risk in large-bodied species is increasing, and that the rate of deterioration has been most accelerated in the Indomalayan and Australasian realms. Expanding agriculture and hunting have been the main drivers of increased extinction risk in mammals. Site-based protection and management, legislation, and captive-breeding and reintroduction programmes have led to improvements in 24 species. We contextualize these changes, and explain why both deteriorations and improvements may be under-reported. Although this study highlights where conservation actions are leading to improvements, it fails to account for instances where conservation has prevented further deteriorations in the status of the world's mammals. The continued utility of the RLI is dependent on sustained investment to ensure repeated assessments of mammals over time and to facilitate future calculations of the RLI and measurement against global targets.     

Risk of extinction of plant communities: Risk and assessment categories

There are many proposals for the assessment of plant communities, based on different criteria, but very few proposals for categorization of the risk of extinction of plant communities (syntaxa). In this paper, concepts related to extent of occurence (EOO), area of occupancy (AOO), extinction and regeneration of plant communities are defined. Also, we propose and define several ranks of extinction risk based on quantitative criteria of the EOO, AOO and processes of decline. The proposals are global, for application to any type of cormophytic vegetation, without geographical restrictions. To check the adequacy of the proposed ranks and its thresholds, the method has been applied to the vegetation of the Iberian Peninsula based on the EOO (122 plant communities) and the AOO (2224 plant communities).     

Carbon isotopic record of terrestrial ecosystems spanning the Late Miocene extinction of Oreopithecus bambolii, Baccinello Basin (Tuscany, Italy)

Oreopithecus bambolii is a Late Miocene hominoid with an extensive fossil record in the Baccinello Basin (Tuscany, Italy), and was the only western European hominoid to survive a major extinction event ca. 9.6 Ma (millions of years ago). Oreopithecus lived in the insular Tusco-Sardinian paleobioprovince, where it evolved many unique anatomical specializations that make it important for understanding the mechanisms and history of Late Miocene hominoid evolution. The eventual extinction of Oreopithecus and its associated fauna ca. 6.5 Ma has generally been attributed to interaction with species that arrived from continental Europe following tectonic collision of the Tusco-Sardinian province with mainland Italy, but palynological, paleontological, and sedimentological records indicate an environmental shift toward more variable climate across the extinction event.To explore the possibility of environmental change as a contributing factor in the extinction of Oreopithecus, we developed a stable carbon and oxygen isotope record from organic matter in paleosols from the Baccinello Basin. These data show very low temporal and spatial variability (indicating plant ecosystem stability through time and space) and provide no evidence for ecologically significant changes in floral composition spanning the extinction event, suggesting that environmental change was not an underlying cause for the extinction of Oreopithecus and its associated fauna. The carbon isotope values fall entirely within the range of isotopic variability for modern plants following the C₃ photosynthetic pathway (trees, shrubs, cool-season grasses), indicating that C₄ vegetation (warm-season grasses) was not an important component of biomass. When corrected for temporal variation in the carbon isotopic composition of atmospheric carbon dioxide, the paleosol carbon isotope values are consistent with predicted values based on modern plants and the Baccinello palynoflora, supporting the reliability of paleosol isotopic records as paleoecological proxies.     

Memory retention of conditioned aversion training in New Zealand's alpine parrot,the kea

New Zealand pest control operations commonly deploy toxic sodium fluoroacetate (1080) baits to control introduced mammalian predators and protect vulnerable native fauna, yet the highly intelligent kea (Nestor notabilis) is at risk of mortality following ingestion of toxic baits intended for their protection. We tested the retention of conditioned aversion in 11 captive kea that had learned to avoid baits containing the bird repellent anthraquinone alongside color, olfactory, and taste cues. We revisited kea over increasing time intervals (3 days, 5 weeks, 3 months, 6 months, and 1 yr) offering them otherwise identical non-repellent baits. Kea retained their aversion until the final session, 1 year after previous exposure to reinforcement, and almost 2 years since previous exposure to repellent. Whether the kea forgot their aversion or the repeated exposures to non-repellent baits resulted in extinction of the aversion, our results indicate that kea are capable of remembering an aversion for long enough to be of practical use to conservation managers in reducing kea mortality through 1080 operations.     

Ecological Predictors of Extinction Risk in the Flora of Lowland England, UK

We used historical and contemporary records to determine the scale of plant extinction in Bedfordshire and Northamptonshire, and to assess whether extinct species share a range of ecological and phytogeographical traits. Since 1700 both counties have lost 94 species (11% of their native floras) with the rate of extinction increasing from 3.8 to 4.8 species per decade in the 19th century to 6–8 species per decade after 1950. The most important predictors of extinction risk were English range size and traits associated with habitat specialisation and competitive ability: poor competitors (i.e. short stress-tolerators) associated with open habitats with very low or high pH and soil moisture (e.g. lowland bogs, dwarf-shrub heath and acid and calcareous grassland) were much more likely to have become extinct in the study region than would have been expected by chance alone. Many of these species have very localised distributions and/or occur at the northern, southern or eastern edges of their range in southern England (i.e. Northern and Oceanic). In contrast, there was no clear or significant relationship between extinction and dispersal ability or reproductive mode. These findings, which parallel national trends, indicate that habitat loss and eutrophication have been the main causes of population extinction in lowland England over the last 300 years. However, more fine-scaled studies are required to assess whether ‘low-level’ stresses, such as habitat fragmentation, climate change and atmospheric pollution, are having additional impacts on populations already severely depleted by habitat loss, as well as to quantify changes in the abundance of more widespread species which are known to have declined over the same period.     

More losers than winners: investigating Anthropocene defaunation through the diversity of population trends

The global-scale decline of animal biodiversity (‘defaunation’) represents one of the most alarming consequences of human impacts on the planet. The quantification of this extinction crisis has traditionally relied on the use of IUCN Red List conservation categories assigned to each assessed species. This approach reveals that a quarter of the world's animal species are currently threatened with extinction, and ~1% have been declared extinct. However, extinctions are preceded by progressive population declines through time that leave demographic ‘footprints’ that can alert us about the trajectories of species towards extinction. Therefore, an exclusive focus on IUCN conservation categories, without consideration of dynamic population trends, may underestimate the true extent of the processes of ongoing extinctions across nature. In fact, emerging evidence (e.g. the Living Planet Report), reveals a widespread tendency for sustained demographic declines (an average 69% decline in population abundances) of species globally. Yet, animal species are not only declining. Many species worldwide exhibit stable populations, while others are even thriving. Here, using population trend data for >71,000 animal species spanning all five groups of vertebrates (mammals, birds, reptiles, amphibians and fishes) and insects, we provide a comprehensive global-scale assessment of the diversity of population trends across species undergoing not only declines, but also population stability and increases. We show a widespread global erosion of species, with 48% undergoing declines, while 49% and 3% of species currently remain stable or are increasing, respectively. Geographically, we reveal an intriguing pattern similar to that of threatened species, whereby declines tend to concentrate around tropical regions, whereas stability and increases show a tendency to expand towards temperate climates. Importantly, we find that for species currently classed by the IUCN Red List as ‘non-threatened’, 33% are declining. Critically, in contrast with previous mass extinction events, our assessment shows that the Anthropocene extinction crisis is undergoing a rapid biodiversity imbalance, with levels of declines (a symptom of extinction) greatly exceeding levels of increases (a symptom of ecological expansion and potentially of evolution) for all groups. Our study contributes a further signal indicating that global biodiversity is entering a mass extinction, with ecosystem heterogeneity and functioning, biodiversity persistence, and human well-being under increasing threat.     

Historical drivers of extinction risk: using past evidence to direct future monitoring

Global commitments to halt biodiversity decline mean that it is essential to monitor species'' extinction risk. However, the work required to assess extinction risk is intensive. We demonstrate an alternative approach to monitoring extinction risk, based on the response of species to external conditions. Using retrospective International Union for Conservation of Nature Red List assessments, we classify transitions in the extinction risk of 497 mammalian carnivores and ungulates between 1975 and 2013. Species that moved to lower Red List categories, or remained Least Concern, were classified as ‘lower risk''; species that stayed in a threatened category, or moved to a higher category of risk, were classified as ‘higher risk''. Twenty-four predictor variables were used to predict transitions, including intrinsic traits (species biology) and external conditions (human pressure, distribution state and conservation interventions). The model correctly classified up to 90% of all transitions and revealed complex interactions between variables, such as protected areas (PAs) versus human impact. The most important predictors were: past extinction risk, PA extent, geographical range size, body size, taxonomic family and human impact. Our results suggest that monitoring a targeted set of metrics would efficiently identify species facing a higher risk, and could guide the allocation of resources between monitoring species'' extinction risk and monitoring external conditions.