Natural and land-use history of the Northwest mountain ecoregions (USA) in relation to patterns of plant invasions

Although the Northwest currently has the least proportion of non-native invasive plant species relative to other regions of North America, invasions continue to increase into the mountainous areas of the region. Landscape structure, such as the variation found along the complex gradients of the Northwest mountain ecoregions, affects the expansion of invasive plant species and the invasibility of plant communities. Also, the history of land use and current use patterns affect the expansion of invasive plants, and many of the deteriorated environments in the region's mountains may invite and stabilize plant invasions. We examined the patterns of invasive plant diversity in Northwest mountain ecoregions, as derived from literature sources, to analyze which factors influence plant invasions. Our analysis found altered riparian systems and disturbed forests to be especially vulnerable to plant invasion. Conversely, alpine and wilderness areas are still relatively unaffected by invasive plants. Both riparian and alpine communities, while making up a relatively small area across Northwest mountain ecoregions, have significant ecological importance and deserve special protection from invasive plant introductions. Human settlement at low elevations and intense land use of upland forests will likely continue to enhance invasive plant introductions into Northwest mountain ecosystems. Knowledge of the relationships between biological and environmental factors, disturbance, and human land use will be critical for future management strategies that proactively locate, prevent, or contain plant invasions in the mountains of the Northwest.     

Alien flora of mountains: global comparisons for the development of local preventive measures against plant invasions

Aim We use data from 13 mountain regions and surrounding lowland areas to identify (1) the origins, traits and cultural uses of alien plant species that establish in mountains, (2) the alien species that are most likely to be a threat and (3) how managers might use this information to prevent further invasions. Location Australia, Canada, Chile, India, New Zealand, South Africa, Spain, Switzerland, USA. Methods Lists of alien species were compiled for mountains and their surrounding or nearby lowlands. Principal co‐ordinates analysis was performed on a matrix of similarities created using presence/absence data for alien species. The significance of differences between means for (1) similarity metrics of lowland and mountain groups and (2) species traits of lowland and mountain alien floras was determined using t‐tests. In seven of the 13 mountain regions, lists of alien species undergoing management were compiled. The significance of differences between proportions of traits for species requiring and not requiring management input was determined with chi‐square tests. Results We found that the proximal lowland alien flora is the main determinant of a mountain region’s alien species composition. The highest similarities between mountain floras were in the Americas/Pacific Region. The majority of alien species commonly found in mountains have agricultural origins and are of little concern to land managers. Woody species and those used for ornamental purposes will often pose the greatest threat. Main conclusions Given the documented potential threat of alien species invading mountains, we advise natural resource managers to take preventive measures against the risk of alien plant invasion in mountains. A strategy for prevention should extend to the surrounding lowland areas and in particular regulate the introduction of species that are already of management concern in other mountains as well as climatically pre‐adapted alien mountain plants. These may well become more problematic than the majority of alien plants currently in mountains.     

A review and meta‐analysis of the effects of climate change on Holarctic mountain and upland bird populations

Mountain regions are globally important areas for biodiversity but are subject to multiple human‐induced threats, including climate change, which has been more severe at higher elevations. We reviewed evidence for impacts of climate change on Holarctic mountain bird populations in terms of physiology, phenology, trophic interactions, demography and observed and projected distribution shifts, including effects of other factors that interact with climate change. We developed an objective classification of high‐elevation, mountain specialist and generalist species, based on the proportion of their breeding range occurring in mountain regions. Our review found evidence of responses of mountain bird populations to climate (extreme weather events, temperature, rainfall and snow) and environmental (i.e. land use) change, but we know little about either the underlying mechanisms or the synergistic effects of climate and land use. Long‐term studies assessing reproductive success or survival of mountain birds in relation to climate change were rare. Few studies have considered shifts in elevational distribution over time and a meta‐analysis did not find a consistent direction in elevation change. A meta‐analysis carried out on future projections of distribution shifts suggested that birds whose breeding distributions are largely restricted to mountains are likely to be more negatively impacted than other species. Adaptation responses to climate change rely mostly on managing and extending current protected areas for both species already present, and for expected colonizing species that are losing habitat and climate space at lower elevation. However, developing effective management actions requires an improvement in the current knowledge of mountain species ecology, in the quality of climate data and in understanding the role of interacting factors. Furthermore, the evidence was mostly based on widespread species rather than mountain specialists. Scientists should provide valuable tools to assess the status of mountain birds, for example through the development of a mountain bird population index, and policy‐makers should influence legislation to develop efficient agri‐environment schemes and forestry practices for mountain birds, as well as to regulate leisure activities at higher elevations.     

Renewable energy development threatens many globally important biodiversity areas

Transitioning from fossil fuels to renewable energy is fundamental for halting anthropogenic climate change. However, renewable energy facilities can be land‐use intensive and impact conservation areas, and little attention has been given to whether the aggregated effect of energy transitions poses a substantial threat to global biodiversity. Here, we assess the extent of current and likely future renewable energy infrastructure associated with onshore wind, hydropower and solar photovoltaic generation, within three important conservation areas: protected areas (PAs), Key Biodiversity Areas (KBAs) and Earth's remaining wilderness. We identified 2,206 fully operational renewable energy facilities within the boundaries of these conservation areas, with another 922 facilities under development. Combined, these facilities span and are degrading 886 PAs, 749 KBAs and 40 distinct wilderness areas. Two trends are particularly concerning. First, while the majority of historical overlap occurs in Western Europe, the renewable electricity facilities under development increasingly overlap with conservation areas in Southeast Asia, a globally important region for biodiversity. Second, this next wave of renewable energy infrastructure represents a ~30% increase in the number of PAs and KBAs impacted and could increase the number of compromised wilderness areas by ~60%. If the world continues to rapidly transition towards renewable energy these areas will face increasing pressure to allow infrastructure expansion. Coordinated planning of renewable energy expansion and biodiversity conservation is essential to avoid conflicts that compromise their respective objectives.     

Do protected areas in urban and rural landscapes differ in species diversity?

Previous studies from Central Europe and North America showed that species richness is higher in urban than in rural landscapes. Do protected areas, which can be found in both city and countryside, reflect this species richness pattern? The impact of urban land-use might reduce conservation success and necessitate special management strategies. We compared species richness and species spatial turnover of selected animal and plant taxa (carabids, butterflies, snails, birds, lichens, mosses, vascular plants) in 30 protected areas in the city of Halle and 56 protected areas in the adjacent rural district of Saalkreis (Central Germany). Species were mapped by experienced biologists within a systematic species inventory. We corrected species numbers for the effects of landscape structure (e.g. size, shape and distance of habitats) which might influence species diversity beyond urbanisation effects. Butterflies, birds and lichens had significantly higher species numbers in the rural protected areas. Species spatial turnover was higher among urban areas than among rural areas or pairs of urban and rural areas for most taxa. Diversity in all taxa depended on the size of a protected area. We discussed these patterns in the context of the general urban-rural species diversity patterns. Our results indicate an increasing isolation of species assemblages with urbanisation and highlight that space for protected areas is even more limited in urban than rural areas. An effective conservation of urban species diversity should include both typical urban and semi-natural habitats to cover the full range of species living in cities.     

Potential relocation of climatic environments suggests high rates of climate displacement within the North American protection network

Ongoing climate change may undermine the effectiveness of protected area networks in preserving the set of biotic components and ecological processes they harbor, thereby jeopardizing their conservation capacity into the future. Metrics of climate change, particularly rates and spatial patterns of climatic alteration, can help assess potential threats. Here, we perform a continent‐wide climate change vulnerability assessment whereby we compare the baseline climate of the protected area network in North America (Canada, United States, México—NAM) to the projected end‐of‐century climate (2071–2100). We estimated the projected pace at which climatic conditions may redistribute across NAM (i.e., climate velocity), and identified future nearest climate analogs to quantify patterns of climate relocation within, among, and outside protected areas. Also, we interpret climatic relocation patterns in terms of associated land‐cover types. Our analysis suggests that the conservation capacity of the NAM protection network is likely to be severely compromised by a changing climate. The majority of protected areas (~80%) might be exposed to high rates of climate displacement that could promote important shifts in species abundance or distribution. A small fraction of protected areas (<10%) could be critical for future conservation plans, as they will host climates that represent analogs of conditions currently characterizing almost a fifth of the protected areas across NAM. However, the majority of nearest climatic analogs for protected areas are in nonprotected locations. Therefore, unprotected landscapes could pose additional threats, beyond climate forcing itself, as sensitive biota may have to migrate farther than what is prescribed by the climate velocity to reach a protected area destination. To mitigate future threats to the conservation capacity of the NAM protected area network, conservation plans will need to capitalize on opportunities provided by the existing availability of natural land‐cover types outside the current network of NAM protected areas.     

Latitudinal comparison of altitudinal changes in forest structure,leaf-type,and species richness in humid monsoon Asia

A new template for mountain vegetation zonation along latitudinal gradients is proposed for examining geographical pattern of various forest attributes in humid monsoon Asia. The contrasting temperature regime in tropical and temperate mountains, i.e., the former is a non-seasonal, temperature-sum controlled environment, and the latter is a seasonal, low temperature limiting environment, leads to different altitudinal patterns of tree height distribution and species richness. In the tropical mountains, both tree height and species richness decrease steeply, and the tree height often stepwise. The decline of tree height and species diversity in the temperate mountains is far less pronounced except near the forest limit. Both trends are explained by their temperature regime.     

Light pollution as an ecological edge effect: Landscape ecological analysis of light pollution in protected areas in Korea

Protected areas have been increasingly encroached upon by light pollution. This paper examines whether patch geometry and land development intensities in protected areas affect the light pollution levels in 22 Korean national parks. Light pollution levels were assessed based on mean nighttime radiance of these national parks derived from nighttime satellite images. Total floor areas of buildings in the parks and in a 1 km buffer zone outside the park boundaries were calculated to assess land development intensities both inside and surrounding the parks. Two landscape metrics (patch area and fractal dimension) were measured to assess the patch geometry of the parks. Results show that the mean nighttime radiances in the Korean national parks are significantly affected by total floor areas in the 1 km buffer zone, but not by the total floor area within the park. This suggests that skyglow caused by artificial light in periphery is a major source of light pollution in the Korean national parks. In other words, light pollution can be seen as an ecological edge effect in protected areas where land development is stringently restricted. This conclusion is also supported by significant effects of two patch geometry variables, i.e., light pollution was more severe in a protected area with smaller size and a more complex shape. Based on these findings, it is suggested to make protected areas larger and more simple-shaped to protect biodiversity from light pollution. Managing lights in periphery of protected areas is also suggested.     

Future land use effects on the connectivity of protected area networks in southeastern Spain

Land-use change is a major driver of the global biodiversity crisis, mainly via the fragmentation and loss of natural habitat. Although land-use changes will accelerate to meet humankind's growing demand for agricultural products, conservation planning rarely considers future land uses and how they may affect the connectivity of ecological networks. Here, we integrate land-use models with landscape fragmentation and connectivity analyses, to assess the effects of past and future land-use changes on the connectivity of protected area networks for a highly dynamic region in southeast Spain. Our results show a continued geographical polarisation of land use, with agricultural intensification and urban development in the coastal areas, and the abandonment of traditional land use in the mountains (e.g., 1100 km² of natural vegetation are projected to be lost in coastal areas whereas 32 km² of natural vegetation would recover in interior areas from 1991 to 2015). As a result, coastal protected areas will experience increasing isolation. The connectivity analyses reveal that the two protected area networks in place in the study area, the European “Natura 2000” and the Andalusian “RENPA” networks, include many landscape connectors. However, we identify two areas that currently lack protection but contain several important patches for maintaining the region's habitat connectivity: the northwestern and the southwestern slopes of the Sierra Cabrera and Bédar protected area. Our results highlight the importance of considering future land-use trajectories in conservation planning to maintain connectivity at the regional scale, and to improve the resilience of conservation networks.     

Targeting Global Protected Area Expansion for Imperiled Biodiversity

Governments have agreed to expand the global protected area network from 13% to 17% of the world''s land surface by 2020 (Aichi target 11) and to prevent the further loss of known threatened species (Aichi target 12). These targets are interdependent, as protected areas can stem biodiversity loss when strategically located and effectively managed. However, the global protected area estate is currently biased toward locations that are cheap to protect and away from important areas for biodiversity. Here we use data on the distribution of protected areas and threatened terrestrial birds, mammals, and amphibians to assess current and possible future coverage of these species under the convention. We discover that 17% of the 4,118 threatened vertebrates are not found in a single protected area and that fully 85% are not adequately covered (i.e., to a level consistent with their likely persistence). Using systematic conservation planning, we show that expanding protected areas to reach 17% coverage by protecting the cheapest land, even if ecoregionally representative, would increase the number of threatened vertebrates covered by only 6%. However, the nonlinear relationship between the cost of acquiring land and species coverage means that fivefold more threatened vertebrates could be adequately covered for only 1.5 times the cost of the cheapest solution, if cost efficiency and threatened vertebrates are both incorporated into protected area decision making. These results are robust to known errors in the vertebrate range maps. The Convention on Biological Diversity targets may stimulate major expansion of the global protected area estate. If this expansion is to secure a future for imperiled species, new protected areas must be sited more strategically than is presently the case.     

Spatial and temporal patterns of changes in protected areas across the Southwestern United States

Protected areas are the core units for preserving habitats and ecological processes. Yet in most regions of the world their geographic, categorical, and institutional evolution remains poorly understood. Here, we report on changes in protected areas in the Southwestern US from 1890 to 2005. Our analysis used the dates of protection of individual parcels in the region to analyze changes by: (a) designating authority (e.g., congressional, administrative), (b) managing agency, (c) protected area types (e.g., wilderness), (d) elevation, (e) ecoregion, and (f) land cover class. In the 1990s, protected area additions tripled compared with the previous decade. Bureau of Land Management (BLM) managed the most protected area after 1990, surpassing that of the US Forest Service. Prior to 1990, most protected areas were found at high elevations, but more recent additions occurred at lower elevations. Land cover types represented in protected areas changed significantly over the last century, with protected areas in forest and woodland systems added prior to 1930 and shrubland, steppe, and savanna systems added after 1980. Additions by BLM occurred mostly by administrative designation. These areas are not permanently protected and so do not provide the level of protection afforded other additions. However these additions are critical for conservation of biodiversity across the region because they occur at elevations and in ecoregions and land cover types that are minimally protected otherwise. Our analysis yielded new insights about permanency, level of protection, and spatial distribution of protected areas, characteristics critical for biodiversity conservation.     

Genetic diversity in the two endangered endemic species Kirengeshoma koreana (Hydrangeaceae) and Parasenecio pseudotaimingasa (Asteraceae) from Korea: Insights into population history and implications for conservation

As mountains have been hypothesized as harboring important Quaternary refugia for plants, one would expect high within-population genetic variation and low or moderate among-population differentiation for those species occurring there. We selected Kirengeshoma koreana and Parasenecio pseudotaimingasa, endemic to mountains of Korea to test the scenario that the main mountain ranges of the Peninsula would also have acted as refugia. We undertook a population genetic analysis using 15 and 12 putative allozyme loci of K. koreana and P. pseudotaimingasa, respectively. We found contrasting levels of genetic diversity in the two species; extremely low within-population genetic variation and high among-population divergence in K. koreana and high within-population genetic variation and moderate among-population divergence in P. pseudotaimingasa. We can conclude that, whereas Korean mountains would have provided large refugial areas (i.e., ‘macrorefugia’) for P. pseudotaimingasa, K. koreana would have endured the Quaternary climate oscillations in small, isolated populations (i.e., ‘microrefugia’). Given the lack of genetic diversity and the extremely low number of populations and individuals of K. koreana, a comprehensive conservation program is urgently needed for this rare and critically endangered species.     

西双版纳勐养自然保护区居住格局研究Ⅱ.成因和影响

使用快速农村评估法和参与性农村评估法对研究区的居住格局及其变化进行了研究 .结果表明 ,西双版纳勐养自然保护区居住格局的形成及变化是在生态环境和社会变革综合作用下进行的 ;生态环境控制着居民点规模和居住格局变化的方向 ,受沟谷地区滋生的病源生物的排斥 ,早期居民点分布在较高的山地 ;社会变革有利于疾病控制 ,驱动了居住格局的变化 ,使居民点向资源丰富的沟谷地区转移 ,为可持续发展奠定了基础 ,也还大面积土地于森林 ,促进了自然保护 ;移民涌入增加的居民点使热带季节雨林的破坏和人与被保护动物争地的矛盾日益突出 ;控制移民和在居民点的层次上协调好保护与发展的关系是缓解这种破坏与矛盾的关键     

Vulnerability of ecosystems to climate change moderated by habitat intactness

The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48 × 48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8 × 4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large‐scale refugia is the priority. In human‐dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large‐scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network.     

Some of the rarest European saproxylic beetles are common in the wilderness of Northern Mongolia

Natural landscapes characterized by heavy disturbance regimes were displaced in Europe by managed cultural landscapes over the past centuries. The associated loss of biological legacies, such as dead or dying trees, has exposed numerous saproxylic species to high risks of extinction. In contrast, extensive wilderness forests in Northern Mongolia have been sustained owing to significant cultural differences. Here we used saproxylic beetle abundance data gathered during two sampling campaigns in the Mongolian taiga to address whether (1) the saproxylic beetle fauna of the Mongolian taiga is comparable to that of European boreal forests, (2) fires are a natural disturbance regime, indicated by the occurrence of many pyrophilous species, and (3) species rare in Europe are also rare in the Northern Mongolian wilderness. Of 191 saproxylic beetle species identified, 150 (79 %) were also found in Europe. The high number of pyrophilous beetle species (20) indicated that natural species communities are well adapted to this disturbance regime. The species rarity in Germany was significantly positively correlated with the species rarity in Finland, but the species rarity in these two countries was negatively correlated with that in the Mongolian wilderness. Our results indicated that wilderness areas with natural disturbances provide biological legacies important for rare species. Therefore, exploitation of the unique, remaining natural landscapes of the Palaearctic wilderness areas should be stopped. Moreover, we urge conservationists to expand controlled burning for restoration at relict sites of rare boreal species also outside Fennoscandia.     

A century of conservation: The ongoing recovery of Svalbard reindeer

Several caribou and reindeer (Rangifer tarandus) populations have experienced recent population declines, often attributed to anthropogenic stressors such as harvesting, landscape fragmentation, and climate change. Svalbard reindeer (R. t. platyrhynchus), the wild reindeer subspecies endemic to the high-Arctic Svalbard archipelago, was protected in 1925, after most subpopulations had been eradicated by harvest. Although direct pressure from harvest has ceased, indirect anthropogenic stressors from environmental changes have increased in this climate change hot spot. An assessment of the current distribution and abundance is therefore urgently needed. We combined distance sampling (300 km transects, n = 489 reindeer groups) and total counts (1,350 km², n = 1,349 groups) to estimate the Svalbard reindeer distribution and abundance across its entire range, which we compared with historical data from the literature and radiocarbon-dated bones. Reindeer have now recolonized nearly all non-glaciated land (i.e., areas occupied prior to human presence), and their spatial variation in abundance reflects vegetation productivity. Independent of vegetation productivity, however, recently recolonized areas have lower reindeer densities than areas not subject to past extirpation. This suggests that recovery from past overharvesting is still in progress. These incompletely recovered areas are potential targets for increased monitoring frequency and maintaining strict conservation to follow the Svalbard management goal (i.e., virtually untouched wilderness areas). Because of such ongoing recolonization, possibly combined with vegetation greening effects of recent warming, our status estimate of Svalbard reindeer abundance (22,435 [95% CI = 21,452–23,425]) is more than twice a previous estimate based on opportunistic counts. Thus, although our study demonstrates the successful outcome of strict harvesting control implemented a century ago, current and future population trajectories are likely shaped by climate change. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Thinking Locally for Urban Forest Restoration: A Simple Method Links Exotic Species Invasion to Local Landscape Structure

Restoring urban forests often involves eradicating exotic species and diligently guarding against future invasions. Understanding how landscape structure contributes to the distribution of exotic species may inform these management efforts. To date, the distribution of exotic species in forested patches has been correlated with the type of development surrounding the patch, with those surrounded by agricultural or urban development often more highly invaded. Yet, previous studies have categorized land use types and have not examined more local-scale changes in land use. These local changes may be particularly important in urban areas where forested patches are immediately surrounded by diverse land use types. Our study examined how two key aspects of landscape structure, patch size and adjacent land use, may influence patterns of exotic species invasion of riparian buffers within Raleigh and Cary, North Carolina, United States. We found that large patch size alone, in our case, wide riparian buffers, does not protect against exotic species invasion. Patches surrounded by higher canopy-cover landscapes (e.g., forests and older residential developments with mature canopy) were more likely to be invaded than those surrounded by less canopy cover (e.g., shopping malls and other commercial development). We attribute these results, in part, to increased pressure from exotic propagules from adjacent forests. When restoring urban forests, attention should be paid to local land use to better plan for successful, long-term eradication of exotic species.     

贵州省山地-坝地系统土地利用与景观格局时空演变

探讨贵州省山地-坝地系统的景观变迁与优化调控具有重要的意义。以贵州省典型的蒲场、洋川山地-坝地系统为例,从一个地貌单元对以万亩大坝为中心的山地-坝地土地系统1960年代到2010年的土地利用变化与格局演变进行系统的研究。把研究区划分成中央坝地、坝中丘陵和坝周山地3个部分,结合遥感技术与实地调查,获得研究区4个时期土地利用的空间分布,基于移动窗口法计算了景观格局指标。坝中丘陵和坝周山地景观多样性高于坝地,土地利用综合程度以坝地最高;平坝耕地从1963年所占比例90.81%下降到2010年的79.94%,坝中丘陵和坝周山地林地减少,灌木林增加,坡耕地仍保持在较高水平;耕地有向经济效益更高的土地利用方式转变的趋势。坝子在土地利用变化和景观格局演变过程中,原有的土地利用格局逐渐被改变,形成新的斑块-廊道-基质格局。研究区中部坝地、坝中丘陵和坝周山地的土地利用变化表明,坝地的土地利用变化和土地集约利用可对坝中丘陵及坝周山地产生影响,坝子与坝中丘陵和坝周山地土地利用存在耦合变化。进一步应加强研究区土地利用优化调控,使坝地、坝周山地和坝中丘陵的土地利用协同演化。研究结果对贵州省山地-坝地系统土地优化利用有参考价值。     

基于土地利用模拟预测模型分析的城市绿色空间发展多情景模拟及建设时序研究——以湛江市中心城区为例

城市绿色空间是未来中国城镇战略发展的重要生态空间载体。城市中心城区的绿色空间生态系统服务价值可作为未来城市生态空间规划的重要依据。生态服务系统之间的权衡或协同关系可通过不同土地利用方式和利用强度表征显现。通过对湛江市中心城区绿色空间应用土地利用模拟预测(PLUS)模型进行自然发展情景与国土空间规划情景双情景下2035年土地利用变化模拟,采用当量因子法及热点分析对生态系统服务价值及其高低值在空间上的聚集程度进行分析,与人类活动强度空间分布进行叠置,得出国土空间规划政策下湛江市中心城区城市绿色空间发展优先级分区,优先化解建设用地与绿色空间发展矛盾,为规划政策提供空间政策的量化数据基础,为其可行性实施、时序安排及预期结果提供数据支撑与建议。结果表明：(1)规划政策情景与自然发展情景未来土地利用模拟结果相比,耕地、林地增多,整体水域得到有效保护,建设用地蔓延受到抑制。(2)生态系统服务价值在2035年规划政策情景>2020年实际情景>2035年自然发展情景,分别约为12.22亿元、11.89亿元、10.53亿元,规划政策情境下生态系统服务价值总量较自然发展情景下提升约1.69亿元,...     

The application of multivariate land classification to vegetation survey in the Wicklow Mountains,Ireland

Multivariate land classification and land cover mapping by aerial photographic interpretation were used to model spatial variation of land cover in the Wicklow Mountains, Ireland and to structure a stratified random sampling programme of upland blanket bog vegetation. The total area of blanket bog with gully-erosion features was estimated as 33% of the area studied. Vegetation with hand peat-cutting patterns was estimated at 5%, and there was 35% undissected (intact) vegetation. There were differences between land classes in the estimated area of land cover with gully-erosion features or hand peat-cutting patterns.Sample vegetation quadrats, stratified by land class and aerial photographic land cover type, were grouped by their plant species composition. The groups represented ombrotrophic mire, soligenous mire and shrub heath vegetation. There was significant association between vegetation group and land class, related to variation in regional landscape type, but no significant association between vegetation group and the aerial photographic land cover types, undissected (intact) and dissected (gullied and cut-over) peats. It is proposed that the similarity of vegetation between undissected and dissected blanket bog is related to vegetation regeneration. The need to consider differences in vegetation distribution, composition and dynamics in ecological management strategies is emphasised. The study demonstrated the value of stratified random field sampling for cost-efficient regional ecological assessment in upland blanket bog landscapes typified by the Wicklow mountains, Ireland.