Multi-Season Regional Analysis of Multi-Species Occupancy: Implications for Bird Conservation in Agricultural Lands in East-Central Argentina

Rapid expansion and intensification of agriculture create challenges for the conservation of biodiversity and associated ecosystem services. In Argentina, the total row crop planted area has increased in recent decades with the expansion of soybean cultivation, homogenizing the landscape. In 2003 we started the first long-term, large-scale bird monitoring program in agroecosystems of central Argentina, in portions of the Pampas and Espinal ecoregions. Using data from this program, we evaluated the effect of land use and cover extent on birds between 2003-2012, accounting for imperfect detection probabilities using a Bayesian hierarchical, multi-species and multi-season occupancy model. We tested predictions that species diversity is positively related to habitat heterogeneity, which in intensified agroecosystems is thought to be mediated by food availability; thus the extent of land use and cover is predicted to affect foraging guilds differently. We also infer about ecosystem services provisioning and inform management recommendations for conservation of birds. Overall our results support the predictions. Although many species within each guild responded differently to land use and native forest cover, we identified generalities for most trophic guilds. For example, granivorous gleaners, ground insectivores and omnivores responded negatively to high proportions of soybean, while insectivore gleaners and aerial foragers seemed more tolerant. Habitat heterogeneity would likely benefit most species in an intensified agroecosystem, and can be achieved with a diversity of crops, pastures, and natural areas within the landscape. Although most studied species are insectivores, potentially beneficial for pest control, some guilds such as ground insectivores are poorly represented, suggesting that agricultural intensification reduces ecological functions, which may be recovered through management. Continuation of the bird monitoring program will allow us to continue to inform for conservation of birds in agroecosystems, identify research needed to reduce key uncertainties, and anticipate the effects of changes in agriculture in central Argentina.     

Germination of <i>Eryngium regnellii</i>: a major species for ecological restoration of plant-pollinator interactions in the Southern Pampas (Buenos Aires,Argentina)

Eryngium regnellii Malme belongs to the largest genera in the Apiaceae family, with 250 species worldwide and 65 represented in South America. It is a herbaceous species typical of hill plant communities, which, along with remnant grassland patches, are the most relevant natural habitats for the maintenance of diversity in the Southern Pampas. Eryngium regnellii is key to the maintenance of pollination mutualisms, being a generalist (displaying a diverse assemblage of pollinators) and ubiquitous species (present in all studied sierras). However, fragmentation of the Pampean landscape due to agricultural intensification has led to the loss of natural environments. Therefore, the reintroduction of E. regnellii in strategic places would facilitate the occurrence of wild pollinators, while favoring pollination services in the agroecosystem. The germination requirements of E. regnellii were studied because a better knowledge of the reproductive biology of this species would provide information relevant to its reproduction and reintroduction into degraded areas. Germination percentages and mean time to germination were evaluated, using one control and two pre-germination treatments: chemical scarification with sulfuric acid, and mechanical scarification with sand paper. Chemical scarified seeds did not germinate. Mechanically scarified and control seed groups showed no significant differences either in germination percentages (49% and 59% respectively) or in mean germination time (13 and 14 days, respectively). Results indicate that E. regnellii shows no physical dormancy, and does not require specific pre-germination treatments for germination under the studied laboratory conditions. The high germination capacity of E. regnellii, along with its ecological attributes, make it a potential species for restoring plant-pollinator interactions in the fragmented landscapes of the Southern Pampas.     

Protected areas as biodiversity benchmarks for human impact: agriculture and the Serengeti avifauna

Protected areas as biodiversity benchmarks allow a separation of the direct effects of human impact on biodiversity loss from those of other environmental changes. We illustrate the use of ecological baselines with a case from the Serengeti ecosystem, Tanzania. We document a substantial but previously unnoted loss of bird diversity in agriculture detected by reference to the immediately adjacent native vegetation in Serengeti. The abundance of species found in agriculture was only 28% of that for the same species in native savannah. Insectivorous species feeding in the grass layer or in trees were the most reduced. Some 50% of both insectivorous and granivorous species were not recorded in agriculture, with ground-feeding and tree species most affected. Grass-layer insect abundance and diversity was much reduced in agriculture, consistent with the loss of insectivorous birds. These results indicate that many species of birds will become confined to protected areas over time. We need to determine whether existing protected areas are sufficiently large to maintain viable populations of insectivorous birds likely to become confined to them. This study highlights the essential nature of baseline areas for assessing causes of change in human-dominated systems and for developing innovative strategies to restore biodiversity.     

Use of agroecosystem matrix habitats by mammalian carnivores (Carnivora): a global‐scale analysis

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Pollination and seed dispersal modes of woody species of 12-year-old secondary forest in the Atlantic Forest region of Pernambuco,NE Brazil

The ability of degraded areas to recover secondary vegetation and the degree of integrity of plant–animal interactions of the resulting vegetation is getting increasingly important for biodiversity and landscape conservation. We studied the seed dispersal and pollination modes of woody species of two 12-year-old secondary forest patches, beforehand used for sugarcane cultivation. Sixty plots were installed with a total area of 0.6 ha. A total of 61 woody species were encountered. Although the study sites were isolated from old-growth forests by the matrix of sugarcane, the array of dispersal modes was the same as in old-growth forest fragments and the percentage of animal-dispersed species was similar (89.8%). The percentage of large-seeded species was even larger than expected (18%), despite the local extinction of large-bodied mammals and birds. Besides the dispersal of large seeds mainly by rodents and bats, more than half of the large-seeded species are consumed by humans and may have reached the study areas this way. Most pollination modes found in forest fragments in the region were also present in the secondary forests; however, no pollination mediated by vertebrates was found among the studied species, neither by birds nor by bats, and a high percentage of species showed an unspecialized pollination mode (55.7%). Due to the high abundance of a few species pollination by hawkmoths was very common among canopy individuals (42.7%), and many sub-canopy individuals were pollinated by large bees (39.8%). The study exemplifies the resilience of sites degraded by intense agriculture, which may still lead to a forest, simplified in plant–animal interactions. Such secondary forest is likely to serve for protection against erosion, and increasing connectivity between forest fragments.     

中国-喜马拉雅三种黄耆属植物与其传粉熊蜂的空间分布预测

依赖于动物传粉获得繁殖成功的植物的分布与其传粉动物的地理分布有着密切联系。预测未来气候变化对植物及其传粉动物地理分布的影响对生物多样性保护具有重要意义。本文通过对中国-喜马拉雅3种黄耆属(Astragalus)植物, 即弯齿黄耆(A. camptodontus)、黑毛黄耆(A. pullus)和笔直黄耆(A. strictus), 及其传粉熊蜂(Bombus)的野外调查, 以及收集来源于数据库的黄耆和熊蜂的543个物种分布点和13个环境因子数据, 结合物种可能出现的完全扩散、不扩散和仅熊蜂扩散3种迁移模式, 利用MaxEnt模型模拟了3种黄耆属植物与2种传粉熊蜂即橘尾熊蜂(Bombus friseanus)和红束熊蜂(B. rufofasciatus)在历史阶段(1970-2000年)和2100年两种温室气体浓度情景(ssp245和ssp585)下的适宜分布区变化。结果表明: 3种黄耆属植物均主要依赖于熊蜂传粉, 黄耆与其传粉熊蜂的主要适宜分布区为中国-喜马拉雅地区, 到2100年它们的分布区呈现向西北方向扩张的趋势, 而在东南部的分布区减少。当模型中考虑与传粉熊蜂的互作后, 3种黄耆属植物的潜在地理分布范围减少了15.83%-83.98%。在温室气体中低浓度情景(ssp245)下, 3种黄耆属植物与其传粉熊蜂的空间匹配增加, 而在高浓度情景(ssp585)下弯齿黄耆、黑毛黄耆与橘尾熊蜂的空间匹配降低; 如果物种不扩散或仅熊蜂扩散, 笔直黄耆与红束熊蜂的空间匹配降低。气候变化和物种的扩散能力可能引起黄耆与其传粉熊蜂出现空间不匹配。同时, 模型预测显示影响黄耆和熊蜂分布的环境因子不同, 但海拔是最主要的环境因子。由于与传粉者的相互作用对许多植物物种的生命周期具有重要意义, 因而本研究可以更好地理解气候变化对植物与其传粉者空间分布的潜在影响, 特别是对那些地理范围受限制的植物。     

Bats are Not Birds – Different Responses to Human Land‐use on a Tropical Mountain

Land‐use intensification has consequences for biodiversity and ecosystem functioning, with various taxonomic groups differing widely in their sensitivity. As land‐use intensification alters habitat structure and resource availability, both factors may contribute to explaining differences in animal species diversity. Within the local animal assemblages the flying vertebrates, bats and birds, provide important and partly complementary ecosystem functions. We tested how bats and birds respond to land‐use intensification and compared abundance, species richness, and community composition across a land‐use gradient including forest, traditional agroforests (home garden), coffee plantations and grasslands on Mount Kilimanjaro, Tanzania. Furthermore, we asked how sensitive different habitat and feeding guilds of bats and birds react to land‐use intensification and the associated alterations in vegetation structure and food resource availability. In contrast to our expectations, land‐use intensification had no negative effect on species richness and abundance of all birds and bats. However, some habitat and feeding guilds, in particular forest specialist and frugivorous birds, were highly sensitive to land‐use intensification. Although the habitat guilds of both, birds and bats, depended on a certain degree of vegetation structure, total bat and bird abundance was mediated primarily by the availability of the respective food resources. Even though the highly structured southern slopes of Mount Kilimanjaro are able to maintain diverse bat and bird assemblages, the sensitivity of avian forest specialists against land‐use intensification and the dependence of the bat and bird habitat guilds on a certain vegetation structure demonstrate that conservation plans should place special emphasis on these guilds.     

The forgotten 60%: bird ecology and management in New Zealand?s agricultural landscape

Production lands make up 58% of Aotearoa?New Zealand?s landcover and contribute greatly not only to the national economy but also to patterns and trends in native and introduced avian biodiversity. However, unlike in native forest and other indigenous habitats, birds in agro-ecosystems have received little attention to date. We argue that this is due to (1) a research focus on understanding the causes of the dramatic decline of New Zealand?s critically endangered, endemic species, (2) an adherence to a ?preservation for intrinsic value? over a ?conservation through sustainable use? paradigm for environmental management, and (3) a historical view of production landscapes as being devoid of endemic and native species and thus of no conservation value. In countering these attitudes, we suggest that the agricultural matrix may contain more native species than many people believe, and that many introduced bird species are key contributors to the social and environmental performance and resilience of these systems. We draw attention to the context, composition, ecology, and status of native and introduced birds in production landscapes in New Zealand, particularly in the face of ongoing agricultural intensification. We first identify the potential roles of local habitat, landscape composition, and introduced predators in shaping farmland bird communities. We then highlight the potential threats and opportunities for birds posed by ongoing intensification, particularly the influences of habitat modification and simplification, increased ecological subsidies through farm inputs, increased stocking rates and yields, and altered predator?prey interactions. We suggest the landscape is the appropriate spatial scale for research and management, and call for an integrated approach to the investigation of farmland birds that combines ecology, sociology, and agro-ecosystems management, and includes farmers, researchers, regulators, and the wider New Zealand public.     

The role of exotic mammals in the diet of native carnivores from South America

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Woody Plant Invasion in Relictual Grasslands

Invasion by alien plants is one of the greatest and most widely distributed causes of man-made changes in ecosystems. One of its most conspicuous variants is the invasion of natural grasslands by exotic trees, which not only means the addition of new taxa to the native biota, but also the introduction of completely new life-forms. In Argentina, the Pampean plain is one of the most highly altered regions and its natural vegetation is only partially conserved in the coastal dunes, swampy lowlands, mountainous areas, riparian habitats, field edges, roadside verges and railway tracksides. Nevertheless, all these habitats are undergoing severe invasions by woody aliens that jeopardize their conservation. We present a preliminary survey of the alien woody plants affecting the last remaining natural grasslands of the Argentine Pampas, the history of their colonization and the phase of the invasion process in which they presently occur. We construct an index of invasion severity to evaluate which woody exotic species should be considered invasive and therefore targeted for control, and to set priorities for the application of management practices according to the seriousness of the threat posed to biodiversity conservation.     

基于粪便DNA及宏条形码技术的食肉动物快速调查及食性分析

在陆地生态系统中, 大型食肉动物对于稳定食物网结构和生态系统功能有重要作用。在世界范围内, 由于栖息地丧失和破碎化、猎杀、人类活动干扰以及病原体的传播, 大型食肉动物生存正面临严重威胁, 多种食肉动物地理分布范围及种群数量大幅度缩减。如何有效保护大型食肉动物物种多样性及种群已经成为世界关注的焦点问题和保护生物学的重要研究方向。川西高原地处我国西南山地与青藏高原东缘交界地带, 属于世界生物多样性热点地区, 是世界大型食肉动物物种最丰富的地区之一, 而日益增强的人类活动可能会加剧对当地动植物资源的破坏, 进而威胁野生食肉动物的生存。获得准确的物种多样性信息及食肉动物食性数据有助于深入了解该地区生态系统结构及食物网关系, 对研究物种共存机制及生物多样性保护有重要意义。本研究通过从四川甘孜藏族自治州新龙县和石渠县野外采集的食肉动物粪便样品中提取DNA, 利用DNA条形码进行物种鉴定, 快速获得该地区食肉动物物种构成信息。38份粪便样品经鉴定来自于7种食肉动物, 分别为5种大型食肉动物(狼Canis lupus、棕熊Ursus arctos、豹Panthera pardus、雪豹P. unica、狗Canis lupus familiaris)和2种中小型食肉动物(豹猫Prionailurus bengalensis、赤狐Vulpes vulpes)。进一步利用高通量测序和宏条形码技术对7种食肉动物粪便中的食物DNA进行精准食性分析, 得到包含19种哺乳类、8种鸟类和1种鱼类共计28个不同的食物分子可操作分类单元(molecular operational taxonomic unit, MOTU)。结果显示, 狼、狗、棕熊最主要的食物来源为偶蹄目动物, 其中取食频率最高的物种为家牦牛(Bos grunniens); 而豹猫和赤狐食物中小型哺乳动物如啮齿目和兔形目占重要比例, 其中高原松田鼠(Neodon irene)和高原鼠兔(Ochotona curzoniae)被取食频率最高。豹和雪豹的食物分别为偶蹄目的中华斑羚(Naemorhedus griseus)和岩羊(Pseudois nayaur)。本研究显示了粪便DNA及宏条形码技术在食肉动物多样性快速调查及高通量精确食性分析中的应用前景, 并为此类研究提供了技术路线的有力借鉴。     

Predation by mustelids and rodents on the eggs and chicks of native and introduced birds in Kowhai Bush, New Zealand

Prior to human settlement the endemic New Zealand avifauna evolved in the absence of mammalian predators. Subsequently mustelids, rodents and feral cats have become established and frequently prey on birds and nests. It has been suggested that, because of their evolutionary history, the endemic birds are especially susceptible to such predators. In this paper predation by mustelids and rodents on the eggs and nestlings of eight species of native bird is compared with that on five species of introduced European passerine inhabiting the same lowland forest.
Final outcomes were known for 101 nests of native birds and 48 nests of introduced birds found during three breeding seasons. There was no significant difference between the two groups in frequency of predation. Native birds lost 70-1% of their nests to predators and introduced birds 64-6%. Most predations occurred during the egg stage. Clutch size did not influence frequency of predation, but brood size did for Fantails and introduced birds. Stoats and weasels were responsible for 77-9% of predations on native birds and 77-4% on introduced birds; corresponding percentages for rodents (principally ship rats) were 14-7% and 19-4%. Mustelids destroyed proportionately more nests with chicks than with eggs, whereas rodents did the reverse. Predation on both groups of birds was not influenced by their nesting habitat, the species of tree used for nesting, or the height and position of the nest. The vulnerability to introduced predators of native New Zealand birds is discussed in relation to the historical declines of many species, and also their life-history patterns.     

Assessing the Threatened Status of Bumble Bee Species (Hymenoptera: Apidae) in Hungary,Central Europe

Decline in the populations of bumble bees and other pollinators stress the need for more knowledge about their conservation status. Only one of the 25 bumble bee species present in Hungary is included in the Hungarian Red List. We estimated the endangerment of the Hungarian bumble bee (Bombus Latr.) species using the available occurrence data from the last 50 years of the 20th century. Four of the 25 species were data deficient or extinct from Hungary. About 60% of species were considered rare or moderately rare. Changes in distribution and occurrence frequency indicated that 10 of the 21 native species showed a declining trend, while only three species increased in frequency of occurrence. According to the IUCN Red List categories, seven species (33% of the native fauna) should be labelled as critically endangered (CR) and 3 (14%) as endangered (EN). Our results stress an urgent need of protection plans for bumble bees in Hungary, and further underlines the validity of concern over bumble bees all over Europe.     

Tree species richness in primary and old secondary tropical forest in Singapore

If secondary succession can accumulate species rapidly, then tropical secondary forests may have an important role to play in the conservation of biodiversity. Data on the floristic composition of forest stands in the Central Catchment Nature Reserve, Singapore, have been analysed to investigate the diversity of approximately 100-year-old tropical secondary forest. Classification using TWINSPAN indicated that three floristic communities could be recognized from 59 0.2 ha plots enumerated for trees >30 cm gbh. These were two types of secondary forest, both dominated by Rhodamnia cinerea (Myrtaceae), and dryland primary forest. The secondary forest was developed on land abandoned after use for agriculture at the end of the 19th century. The 16 primary forest plots contained a total of 340 species, more than the 281 recorded from the 43 plots of the two secondary forest types combined. The mean species number per plot in the more diverse of the two secondary forests was only about 60% of the primary forest. Thus the secondary forest, despite a century or so for colonization by species and the presence of contiguous primary forest, was still significantly less diverse than primary forest areas. It is concluded that secondary forest cannot be assumed to accrete biodiversity rapidly in the tropics, and may not be of direct value in conservation. However, other indirect roles, such as providing resources for native animals, and buffering and protecting primary forest fragments may make the protection of secondary forest worthwhile.     

Do biodiversity hotspots match with rodent conservation hotspots?

Biodiversity hotspots are used widely to designate priority regions for conservation efforts. It is unknown, however, whether the current network of hotspots adequately represents globally threatened taxonomic diversity for whole plant and animal groups. We used a mammalian group traditionally neglected in terms of conservation efforts, the rodents, in order to test whether biodiversity hotspots match the current distribution of threatened taxa (genera and species). Significantly higher numbers of threatened rodent genera and species fell within biodiversity hotspots; nonetheless over 25% of the total threatened genera and species did not occur in any biodiversity hotspot. This was particularly true for the Australian region, where 100% of the threatened genera and species fell outside biodiversity hotspots, with many threatened taxa found in Papua-New Guinea. We suggest to officially including Papua New Guinea among biodiversity hotspots for rodents, and also the steppic/semidesert areas of central Asia.     

Nature conservation at the edge

Currently, there is an increasing need for evidence-based strategies in nature conservation, for example when designing and establishing nature reserves. In this contribution, we critically assess the ecological relevance of recent nature conservation practices in Kenya (East Africa), a region of global biodiversity hotspots. More specifically, we overlay the distribution of species richness (here based on mammals, birds, amphibians and vascular plants) with the location of nature reserves, the Kenyan agro-ecological zones (areas representing diverging agricultural potentials), and with the spatial distribution of human population density. Our analyses indicate that the majority of protected areas are located in areas with comparatively low species richness, while areas with extraordinary high levels of species richness are not adequately covered by nature reserves. Areas of high agricultural productivity (and with high human demographic pressure) are mainly reserved for high-yield agriculture; however, these regions are also characterised by high species richness. The majority of nature reserves are restricted to the semi-arid regions of Kenya, marginal for agricultural usage, but also with low levels of species richness. Based on this analysis, we prioritize areas for future protection. This single-country case illustrates that agricultural production in high-yield areas outweighs nature conservation goals, even in global biodiversity hotspot regions, and that priority setting may conflict with effective nature conservation.     

Ecology and conservation of grassland birds in southeastern South America: a review

ABSTRACT The grasslands of southeastern South America (SESA), comprising one of the most extensive grassland ecosystems in the Neotropics, have been negatively impacted by the development of the livestock industry, arable agriculture, and forestry. SESA grasslands have a rich avifauna that includes 22 globally threatened and near‐threatened species, and many other species have suffered local population extinctions and range reductions. In addition to habitat loss and fragmentation, grassland birds in SESA are threatened by improper use of agrochemicals, unfavorable fire management regimes, pollution, and illegal capture and hunting. Studies to date have provided information about the distribution of grassland birds, the threats populations face, and the habitat requirements of some threatened species, but more information is needed concerning dispersal and migration patterns, genetics, and factors that influence habitat use and species survival in both natural and agricultural landscapes. There are few public protected areas in the region (1% of original grasslands), and many populations of threatened grassland birds are found on private lands. Therefore, efforts to preserve grassland habitat must reconcile the interests of land owners and conservationists. Current conservation efforts include establishment of public and private reserves, promotion of agricultural activities that reconcile production with biodiversity conservation, development of multilateral conservation projects across countries, and elaboration of action plans. Measures that result in significant losses to private land owners should include economic compensation, and use of economic incentives to promote agriculture and forestry in native grassland areas should be discouraged, especially in priority areas for grassland birds. Although more studies are needed, some actions, particularly habitat protection and improved management of public and private lands, should be taken immediately to improve the conservation status of grassland birds in SESA.     

Bird assemblages in fragmented agricultural landscapes: the role of small brigalow remnants and adjoining land uses

Agricultural intensification typically leads to changes in bird diversity and community composition, with fewer species and foraging guilds present in more intensively managed parts of the landscape. In this study, we compare bird communities in small (2–32 ha) brigalow (Acacia harpophylla) remnants with those in adjacent uncultivated grassland, previously cultivated grassland and current cropland, to determine the contribution of different land uses to bird diversity in the agricultural landscape. Twenty remnant brigalow patches and adjacent agricultural (‘matrix’) areas in southern inland Queensland, Australia were sampled for bird composition and habitat characteristics. The richness, abundance and diversity of birds were all significantly higher in brigalow remnants than in the adjacent matrix of cropping and grassland. Within the matrix, species richness and diversity were higher in uncultivated grasslands than in current cultivation or previously cultivated grasslands. Forty-four percent of bird species were recorded only in brigalow remnants and 78% of species were recorded in brigalow and at least one other land management category. Despite high levels of landscape fragmentation and modification, small patches of remnant brigalow vegetation provide important habitat for a unique and diverse assemblage of native birds. The less intensively managed components of the agricultural matrix also support diverse bird assemblages and thus, may be important for local and regional biodiversity conservation.     

Rodent seed predation on tree invader species in grassland habitats of the inland Pampa

Woody plant invasion in grassland ecosystems is a worldwide phenomenon, and biotic interactions as competition and predation have been invoked as a possible barrier to woody encroachment in many ecosystems. We evaluated the role of rodents as seed predators in Pampean grasslands, and we assessed the differences in removal by rodents between one native species, Prosopis caldenia (Caldén) and one exotic species, Gleditisia triacanthos (Honey locust). The experiment was conducted at different phases of the rodent population cycle in two grassland communities, a remnant of a native grassland and a post agriculture grassland (old field). The amount of seed loss caused by predation was estimated by a bait-removal experiment in foraging stations. We estimated the frequency of foraging stations with consumption, the overall amount of seed predation and the individual rate of seed predation. The total amount of seed removal and the individual rate of seed removal were higher for P. caldenia than for G. triacanthos, in the native grassland than in the old field, and in autumn when rodent density was maximum. Overall, the role of rodents on woody seed removal varied according to the plant species and depending on the local conditions that vary through time and space.     

A global review of the impacts of invasive cats on island endangered vertebrates

Cats are generalist predators that have been widely introduced to the world's ~179 000 islands. Once introduced to islands, cats prey on a variety of native species many of which lack evolved defenses against mammalian predators and can suffer severe population declines and even extinction. As islands house a disproportionate share of terrestrial biodiversity, the impacts of invasive cats on islands may have significant biodiversity impacts. Much of this threatened biodiversity can be protected by eradicating cats from islands. Information on the relative impacts of cats on different native species in different types of island ecosystems can increase the efficiency of this conservation tool. We reviewed feral cat impacts on native island vertebrates. Impacts of feral cats on vertebrates have been reported from at least 120 different islands on at least 175 vertebrates (25 reptiles, 123 birds, and 27 mammals), many of which are listed by the International Union for the Conservation of Nature. A meta‐analysis suggests that cat impacts were greatest on endemic species, particularly mammals and greater when non‐native prey species were also introduced. Feral cats on islands are responsible for at least 14% global bird, mammal, and reptile extinctions and are the principal threat to almost 8% of critically endangered birds, mammals, and reptiles.