Despite containing extraordinary levels of biodiversity, lowland (<200 m asl) tropical forests are extremely threatened globally. Southeast Asia is an area of high species richness and endemicity ...under considerable anthropogenic threat with, unfortunately, scant focus on its lowland forests. We estimated extent of lowland forest loss from 1998 to 2018, including inside protected areas and determined the vulnerability of this remaining forest. Maximum likelihood classification techniques were used to classify Landsat images to estimate lowland forest cover in 1998 and 2018. We used Bayesian belief networks with 20 variables to evaluate vulnerability of the forest that remained in 2018. Analyses were conducted at two spatial scales: landscape patch (analogous to ecoregion) and country level. Over 20 years, >120,000 km2 of forest (50% of forest present in 1998) was lost. Of the 14 lowland forest patches, 6 lost >50% of their area. At the country scale, Cambodia had the greatest deforestation (>47,500 km2). In 2018, 18% of the lowlands were forested, and 20% of these forests had some formal protection. Approximately 50% of the lowland forest inside protected areas (c. 11,000 km2) was also lost during the study period. Most lowland forest remaining is highly vulnerable; eight landscape patches had >50% categorized as such. Our results add to a growing body of evidence that the presence of protected areas alone will not prevent further deforestation. We suggest that more collaborative conservation strategies with local communities that accommodate conservation concessions specifically for lowland forests are urgently needed to prevent further destruction of these valuable habitats.
Pérdida y Vulnerabilidad de los Bosques de Tierras Bajas en la Parte Continental del Sudeste Asiático
Resumen
A pesar de que contienen niveles extraordinarios de biodiversidad, los bosques tropicales de tierras bajas (<200 m snm) se encuentran bajo amenazas extremas en todo el mundo. El sudeste de Asia es un área con una riqueza alta de especies y endemismos bajo amenazas antropogénicas considerables, desafortunadamente, con un enfoque exiguo sobre sus bosques de tierras bajas. Estimamos la extensión de la pérdida de bosques de tierras bajas desde 1998 hasta 2018, incluyendo aquellos bosques que se encuentran dentro de áreas protegidas, y determinamos la vulnerabilidad del bosque que permanece. Usamos técnicas de clasificación de la probabilidad máxima para clasificar imágenes Landsat y así estimar la cobertura de bosque de tierras bajas en 1998 y 2018. Usamos redes de opinión bayesiana con 20 variables para evaluar la vulnerabilidad del bosque que permanecía en pie en 2018. Los análisis fueron realizados a dos escalas espaciales: a nivel de fragmento de paisaje (análogo a la ecorregión) y a nivel de país. A lo largo de 20 años, se perdieron >120,000 km2 de bosque (50% del bosque presente en 1998). De los 14 fragmentos de bosque de tierras bajas, seis perdieron >50% de su área. A la escala de país, Camboya tuvo la mayor deforestación (>47,500 km2). En 2018, el 18% de las tierras bajas contaban con bosque y el 20% de estos bosques tenían algún tipo de protección formal. Aproximadamente el 50% del bosque de tierras bajas que se encuentra dentro de áreas protegidas (aprox. 11,000 km2) también se perdió durante el periodo de estudio. La mayoría del bosque de tierras bajas que todavía permanece tiene una vulnerabilidad muy alta; ocho de los fragmentos de paisaje tenían >50% categorizado de tal manera. Nuestros resultados se suman a un cuerpo creciente de evidencia de que la sola presencia de las áreas protegidas no va a prevenir una mayor deforestación. Sugerimos que se necesitan urgentemente más estrategias de conservación colaborativa con comunidades locales que acomoden las concesiones de conservación específicamente para los bosques de tierras bajas para prevenir una mayor destrucción de estos hábitats tan valiosos.
【摘要】
低地 (海拔低于两百米) 热带森林拥有及其丰富的生物多样性, 但在全球范围内正面临严重威胁。东南亚地区的物种丰富度和特有性很高, 同时也受到严重的人为威胁, 而不幸的是该地区的低地森林很少得到关注。本研究估计了1998 年至 2018 年包括保护区内部的低地森林的丧失程度, 并确定了剩余森林的脆弱性。我们利用最大似然分类法对 Landsat 陆地卫星图像进行了分类, 以估计低地森林覆盖面积在1998 年至 2018 年的变化, 并使用有 20 个变量的贝叶斯信念网络评估了 2018 年剩余森林的脆弱性。分析在景观斑块 (类似于生态区域) 和国家水平这两个空间尺度上进行。结果表明, 20 多年来, 有 12 万平方公里的森林消失了, 占 1998 年森林总面积的 50%。在 14 个低地森林斑块中, 6 个斑块的面积丧失达到 50% 。在国家尺度上, 柬埔寨森林丧失的情况最为严重 (>47,500 平方公里) 。2018 年, 18% 的低地被森林覆盖, 其中 20% 的森林受到正式保护。研究期间保护区内有大约 50% 的低地森林 (约 11000 平方公里) 已丧失。剩下的低地森林大多高度脆弱, 这类森林占 8 个景观斑块中超过 50% 的地区。我们的研究结果进一步证明, 仅靠建立保护区并不足以阻止森林丧失。我们建议, 为了防止这些宝贵的栖息地继续遭到破坏, 目前迫切需要与当地社区采取更多的合作保护策略, 以适应低地森林的保护特许协议。【翻译: 胡怡思; 审校: 聂永刚】关键词
Article impact statement: From 1998 to 2018, mainland Southeast Asia lost 50% of its lowland forest, including a 50% loss inside protected areas.
Land conversion is having major impacts on wildlife globally, and thus understanding and predicting patterns of land conversion is an important component of conservation planning. Southeast Asia is ...undergoing rapid habitat conversion; however, most countries in the region have very limited human resources devoted to planning, and typically land-cover trend assessments are often challenging. Here we demonstrate a rapid method for land-cover change quantification for areas of terrestrial, mangrove and peat swamp forests at high risk from land conversion that can be quickly and simply predicted using southern Thailand as an example. Land-cover maps from two time periods (1995/1996 and 2015/2016) were produced and compared to determine changes between the two time periods. Five land-cover categories (terrestrial forest, mangrove forest, peat swamp forest, human settlement, agriculture) were estimated along with land-cover changes. Hot spots of high percentage change for human settlement and agriculture were identified, and vulnerable habitats were mapped including terrestrial forest, mangrove forest and peat swamp forest. Between 1996 and 2016, 22.1% of terrestrial forests, 26.2% of mangrove forests and 55% of peat swamp forests were lost. The losses of these natural habitats were clearly associated with agricultural expansion. Approximately 10.6%, 14.3% and 33% of terrestrial, mangrove and peat swamp forest remaining were identified as highly vulnerable, of which the majority were at the boundaries between natural and human-dominated areas. The technique offers promise for rapidly identifying high priority areas for more detailed analysis and potential conservation interventions.
Zoonosis-based epidemics are inevitable unless we revisit our relationship with the natural world, protect habitats, and regulate wildlife trade, including live animals and non-sustenance products. ...To prevent future zoonoses, governments must establish effective legislation addressing wildlife trade, protection of habitats, and reduction of the wildlife–livestock–human interface.
Bayesian networks (BN) have been increasingly used for habitat suitability modeling of threatened species due to their potential to construct robust models with limited survey data. However, previous ...applications of this approach have only occurred in countries where human and budget resources are highly available, but the highest concentrations of threatened vertebrates globally are located in the tropics where resources are much more limited. We assessed the effectiveness of Bayesian networks in generating habitat suitability models in Thailand, a biodiversity-rich country where the knowledge base is typically sparse for a wide range of threatened species. The Bayesian network approach was used to generate habitat suitability maps for 52 threatened vertebrate species in Thailand, using a range of evidence types, from relatively well-documented species with good local knowledge to poorly documented species, with few local experts. Published information and expert knowledge were used to define habitat requirements. Focal species were categorized into 22 groups based on known habitat preferences, and then habitat suitability models were constructed with outcomes represented spatially. Models had a consistent structure with three major components: potential habitat, known range, and threat level. Model classification sensitivity was tested using presence-only field data for 21 species. Habitat models for 12 species were relatively sensitive (>70% congruency between observed and predicted locations), three were moderately congruent, and six were poor. Classification sensitivity tended to be high for bird models and moderate for mammals, whereas sensitivity for reptiles was low, presumably reflecting the relatively poor knowledge base for reptiles in the region. Bayesian network models show significant potential for biodiversity-rich regions with scarce resources, although they require further refinement and testing. It is possible that one detailed ecological study is sufficient to develop a model with reasonable sensitivity, but BN models for species groups with no quantitative data continue to be problematic.
Dying on the vine Gale, George
2011, 2011., 20110705, 2011-07-05
eBook, Book
Dying on the Vine chronicles 150 years of scientific warfare against the grapevine's worst enemy: phylloxera. In a book that is highly relevant for the wine industry today, George Gale describes the ...biological and economic disaster that unfolded when a tiny, root-sucking insect invaded the south of France in the 1860s, spread throughout Europe, and journeyed across oceans to Africa, South America, Australia, and California--laying waste to vineyards wherever it landed. He tells how scientists, viticulturalists, researchers, and others came together to save the world's vineyards and, with years of observation and research, developed a strategy of resistance. Among other topics, the book discusses phylloxera as an important case study of how one invasive species can colonize new habitats and examines California's past and present problems with it.
Animal movement and resource use are tightly linked. Investigating these links to understand how animals use space and select habitats is especially relevant in areas affected by habitat ...fragmentation and agricultural conversion. We set out to explore the space use and habitat selection of Burmese pythons (Python bivittatus) in a heterogenous, agricultural landscape within the Sakaerat Biosphere Reserve, northeast Thailand. We used VHF telemetry to record the daily locations of seven Burmese pythons and created dynamic Brownian Bridge Movement Models to produce occurrence distributions and model movement extent and temporal patterns. To explore relationships between movement and habitat selection we used integrated step selection functions at both the individual and population level. Burmese pythons had a mean 99% occurrence distribution contour of 98.97 ha (range 9.05-285.56 ha). Furthermore, our results indicated that Burmese pythons had low mean individual motion variance, indicating infrequent moves and long periods at a single location. In general, Burmese pythons restricted movement and selected aquatic habitats but did not avoid potentially dangerous land use types like human settlements. Although our sample is small, we suggest that Burmese pythons are capitalizing on human disturbed landscapes.
Global population declines of insect pollinators highlight the need for a greater ecological understanding of the responses of wild pollinators to local management actions and to human alterations of ...landscapes, especially in the tropics where crops are highly dependent on wild pollinators.
We examined the effects of local and landscape factors on the richness and abundance of bees in farms around Bangkok, Thailand. Bee communities in 24 mango (Mangifera indica L.) orchards in heavily modified landscapes (61–99% anthropogenic land cover) were compared. We predicted that bees would be more species rich in orchards with higher flower diversity, whereas small‐sized bees with non‐eusocial and/or below‐ground nesting habits would be more sensitive to human disturbance, and hence rare.
Twenty‐eight species were caught and individuals of genus Apis comprised >92% of 3842 bees sampled and dominated all 24 sites.
Habitat effects on bee richness and abundance were stronger at the farm scale than at the landscape scale. At the farm scale, total bee richness and abundance, as well as small, non‐eusocial and below‐ground nesting bee richness and abundance, were negatively associated with field size and positively associated with flowering plant diversity. The percentage of urban land cover within a 1‐km radius was weakly but positively related to total bee richness and small‐sized bee richness; total bee abundance was positively associated with wetland cover.
A greater diversity of flowering plants retained in smaller fields maintained higher bee richness and abundances, particularly small‐sized bees. Farmers can enhance bee populations by maintaining small patches of flowers in their fields.
Historically, designation of protected areas was biased toward specific habitats, resulting in insufficient representation of other habitats and their associated species. We identified gaps in ...current protected areas of the Indo-Burma Hotspot, proposed additional areas that could be included in PA systems of this hotspot to increase overall representation, and identified high priority areas for inclusion. Land cover types and threatened terrestrial vertebrate species were used as surrogates of biodiversity, and their representations were assessed using a gap analysis. Areas to be added to improve the hotspot's protected area systems were identified using Marxan software. High priority areas were selected based on irreplaceability and vulnerability. The representation of biodiversity in this hotspot is currently skewed in terms of habitats and species. There is a bias toward mammals in terms of representation (75%), while amphibians are not well represented (27%). With our optimal scenario, 21% of the hotspot's entire land area would need to be included in protected area systems, compared to 16% currently, to achieve more complete representation targets. Myanmar had the most additional areas required. Two-thirds of the additional areas needed to represent conservation features were <10km2. Several suggested areas were located along borders between multiple countries. Representation within protected areas in the Indo-Burma Hotspot can be significantly improved by focusing on maintaining and restoring linkages between smaller patches to create and sustain larger protected area networks. As part of this enhancement, trans-boundary collaboration among countries within the hotspot will be particularly important.
•Representations of biodiversity in Indo-Burma Hotspot are unequal.•A scenario to increase representation of protected areas in the hotspot is proposed.•Mammals received the best representation, while amphibians received the worst.•Most of the large proposed areas to be added are located in Myanmar and Cambodia.•Trans-boundary collaboration among countries is essential for conservation success.
Available habitat and hence the global population of the Endangered giant nuthatch Sitta magna, restricted to lower montane habitats of south-western China, eastern Myanmar and northern Thailand, ...remains poorly quantified. Thailand is the only portion of the species’ range for which there is a population estimate. To obtain a more precise estimate of the Thai population and clarify the extent and characteristics of suitable habitat remaining, we conducted 335 point-count surveys at 67 points across eight localities during November 2019–February 2020. We estimated abundance and identified preferred habitat characteristics using N-mixture models, and created suitable habitat maps based on data from surveys and remote sensing. Our estimate for Thailand was 578 (95% CI 391–854) individuals based on a density of 3.7 (95% CI 2.5–5.5) individuals/km2 in 156 km2 of suitable habitat. The giant nuthatch prefers dry forest with a large amount of mature native or planted pine Pinus kesiya and with a large tree basal area and an open canopy. Our estimate of suitable habitat remaining was less than previously reported and thus the population has probably decreased, although most of this habitat is within protected areas. Habitats for the species in Thailand have a stronger level of protection than in Myanmar and China, although habitat in China remains unquantified. We recommend further research in Myanmar and China, which may hold the majority of available habitat for the giant nuthatch. For long-term management, detailed study of the association of the giant nuthatch with pine plantations is required.
Species’ life‐history traits have a wide variety of applications in ecological and conservation research, particularly when assessing threats. The development and growth of global species’ trait ...databases are critical for improving trait‐based analyses; however, it is vital to understand the gaps and biases in the available data.
We reviewed bat wing morphology data, specifically mass, wingspan, wing area, wing loading, and aspect ratio, to identify issues with data reporting and ambiguity. Additionally, we aimed to assess taxonomic and geographic biases in trait data coverage.
We found that most studies used similar field methodology, but that data reporting and quality were inconsistent/poor. Additionally, we noted several issues regarding semantic ambiguity in trait definitions, specifically around what constitutes wing area.
Globally, we found that bat wing morphology trait coverage was low. Only six bat families had ≥40% trait coverage, and, of those, none consisted of more than 11 species in total. We found similar biases in trait coverage across International Union for Conservation of Nature Red List categories, with threatened species having lower coverage.
Geographically, North America, Europe, and the Indomalayan regions exhibited higher overall trait coverage, while both the Afrotropical and Neotropical ecoregions showed poor trait coverage.
The underlying biases and gaps in bat wing morphology data have implications for researchers conducting global trait‐based assessments. Implementing imputation techniques may address missing data, but only for smaller regional subsets with substantial trait coverage.
Due to generally low overall trait coverage, increasing species’ representation in the database should be prioritised. We suggest adopting an Ecological Trait Standard Vocabulary to reduce semantic ambiguity in bat wing morphology traits, to improve data compilation and clarity. Additionally, we advocate that researchers adopt an Open Science approach to facilitate the growth of a bat wing morphology trait database.
The shape and design of bat wings, known as wing morphology, provide a valuable link to a species' natural history and vulnerability to threats. While in some areas we have good data coverage on wing morphology traits, globally a low number of species have available data particularly in species‐rich tropical regions. A centralised database and terminology will help improve our knowledge on bat wing morphology and allow easier use by bat scientists.
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