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991.
高山和极地植物功能生态学研究进展 总被引:10,自引:0,他引:10
由于环境条件恶劣,所以高山地区(特别是树木分布线以上区域)和极地地区通常被认为是陆地上最为极端的生境之一,但是高山和极地区域却也拥有众多极具价值的生物资源。因此自1896年以来,作为生物进化研究中的热点和难点。高山和极地植物对生境的适应机制和策略一直倍受研究者们的关注。本文以植物生态学、植物生理学、气象学等学科资料,分析了高山和北极植物的特有生活型,并认为它是一种主要的适应机制。通过对全球主要高山和极地植物生长地的局部气候特点的分析,作者肯定了植物的特化适应现象与极端环境各因素间存在的密切关系。 相似文献
992.
Matthew K. Chew 《Journal of the history of biology》2009,42(2):231-266
Dispersal of biota by humans is a hallmark of civilization, but the results are often unforeseen and sometimes costly. Like
kudzu vine in the American South, some examples become the stuff of regional folklore. In recent decades, “invasion biology,”
conservation-motivated scientists and their allies have focused largely on the most negative outcomes and often promoted the
perception that introduced species are monsters. However, cases of monstering by scientists preceded the rise of popular environmentalism.
The story of tamarisk (Tamarix spp.), flowering trees and shrubs imported to New England sometime before 1818, provides an example of scientific “monstering”
and shows how slaying the monster, rather than allaying its impacts, became a goal in itself. Tamarisks’ drought and salt
tolerance suggested usefulness for both coastal and inland erosion control, and politicians as well as academic and agency
scientists promoted planting them in the southern Great Plains and Southwest. But when erosion control efforts in Arizona,
New Mexico and Texas became entangled with water shortages, economic development during the Depression and copper mining for
national defense during World War Two, federal hydrologists moved quickly to recast tamarisks as water-wasting foreign monsters.
Demonstrating significant water salvage was difficult and became subsidiary to focusing on ways to eradicate the plants, and
a federal interagency effort devoted specifically to the latter purpose was organized and continued until it, in turn, conflicted
with regional environmental concerns in the late 1960s. 相似文献
993.
The Impact of Energy Management Control Systems on Energy Efficiency in the German Manufacturing Industry 下载免费PDF全文
Although previous studies point to much (untapped) potential for energy efficiency enhancement in industry, empirical research that adapts findings of environmental control to the context of energy management remains widely neglected. Specifically, previous environmental research suggests that the implementation of energy management control systems (EnMCS) could be an effective lever for companies to enhance their production systems and operations toward energy efficiency. Yet, empirical evidence for this theoretical proposition is rather missing; thus, debate continues regarding whether the high investments to set up a comprehensive EnMCS pay off in the long run. Based on a sample of 236 German manufacturing companies, this study combines primary data that capture the configuration of EnMCS with secondary data that were used to calculate energy efficiency. The results provide evidence that the extent of EnMCS implementation positively relates to firms’ energy efficiency. Findings from additional moderation analysis suggest that companies might enhance the relationship of EnMCS and energy efficiency performance by establishing a full‐time energy manager or by using external energy consulting support. 相似文献
994.
T. Kraaij 《South African Journal of Botany》2011,77(2):455-473
Six-hundred-and-fifty plant species from 280 genera and 85 families have been recorded as indigenous to the Bontebok National Park (BNP), which lies 5 km south of Swellendam, in the Western Cape. Twenty-nine of these plant species are globally threatened with extinction and another 23 are species of conservation concern. Three species (Aspalathus burchelliana, Diosma fallax, Erica filamentosa) are endemic to the park. The Asteraceae, Iridaceae and Fabaceae ranked high as speciose families, in line with the Cape Floristic Region (CFR) as a whole, while the Asphodelaceae, Crassulaceae, Poaceae and Cyperaceae were overrepresented, and the Rutaceae, Proteaceae and Ericaceae underrepresented at BNP. The largest genera were Aspalathus (19 species), Crassula (17), Pelargonium (16), Erica (15), Oxalis (12), Moraea (11), Helichrysum (10) and Hermannia (10). Geophytes were the dominant growth form (23% of species recorded), followed by dwarf shrubs (20%), herbs (16%), graminoids (15%), shrubs (13%), succulents (8%), trees (3%) and climbers (2%). Forty alien plant species were recorded (likely an underestimate of true numbers) with the Poaceae most speciose and arguably the biggest invasive threat at the park. With 20 plant species/km2, the flora of BNP is richer than expected based on its location within the south-eastern CFR. Similarity with floras of other lowland and montane protected areas in the region is low (< 33% and < 20% respectively), demonstrating that a large component of BNP's flora is not conserved elsewhere. Within a landscape context, BNP forms part of a cluster of connected core sites for Renosterveld conservation. This work confirms the high importance of BNP for flora conservation nationally and even globally. 相似文献
995.
Calcicole plant species are vulnerable to acidification and fertilization, caused by deposition and changes in land use, since they are adapted to nutrient-poor calcareous conditions. In this study we used vegetation data (vascular plants, bryophytes and lichens) from 1964 and 1985 and stored soil samples from 1966 to investigate long-term soil chemistry and vegetation changes in a semi-natural, sandy calcareous grassland in southern Sweden. In the re-investigation in 2008 we found that increased decalcification due to acidification could not be verified. The plant community had changed from stress-tolerant calcareous grassland towards a community promoted by higher nutrient availability. Furthermore, the cover of species indicating calcareous conditions had decreased. A decline in the cover of species adapted to alkaline, phosphorus-poor conditions may be due to increased nutrient availability, but there were also indications that the vegetation had changed due to overgrowth by woody plants. This long-term impoverishment of the plant community highlights the need for appropriate management of calcareous grasslands, in order to limit the nutrients available in the soil and prevent overgrowth by shrubs and trees. 相似文献
996.
《Basic and Applied Ecology》2014,15(4):279-287
Environmental changes due to land use developments, climate change and nitrogen deposition have profound influences on species assemblages. Investigating the dynamics in species composition as a function of underlying traits may increase our understanding of ecosystem functioning and provide a basis for effective conservation strategies. Here, I use a broad array of species traits for butterflies to identify four main components of associated traits. These reflect the spatial use of the landscape, abiotic vulnerability, developmental rate and phenology, and food specialisation, respectively. The first three trait components each contribute to determine Red List status, but only the developmental rate and phenology component is related to recent population trends. I argue that the latter component reflects the environmental impact of nutrient availability and microclimate, as affected by nitrogen deposition. This perspective sheds a new light on ongoing changes in community composition. Thus, a multidimensional view of trait associations allows us to move beyond the simplistic specialist–generalist dichotomy, renew our view on species-specific studies and help in setting new priorities for conservation. 相似文献
997.
The role of natural environments in the evolution of resistance traits in pathogenic bacteria 总被引:1,自引:0,他引:1
Jose L. Martinez 《Proceedings. Biological sciences / The Royal Society》2009,276(1667):2521-2530
Antibiotics are among the most valuable compounds used for fighting human diseases. Unfortunately, pathogenic bacteria have evolved towards resistance. One important and frequently forgotten aspect of antibiotics and their resistance genes is that they evolved in non-clinical (natural) environments before the use of antibiotics by humans. Given that the biosphere is mainly formed by micro-organisms, learning the functional role of antibiotics and their resistance elements in nature has relevant implications both for human health and from an ecological perspective. Recent works have suggested that some antibiotics may serve for signalling purposes at the low concentrations probably found in natural ecosystems, whereas some antibiotic resistance genes were originally selected in their hosts for metabolic purposes or for signal trafficking. However, the high concentrations of antibiotics released in specific habitats (for instance, clinical settings) as a consequence of human activity can shift those functional roles. The pollution of natural ecosystems by antibiotics and resistance genes might have consequences for the evolution of the microbiosphere. Whereas antibiotics produce transient and usually local challenges in microbial communities, antibiotic resistance genes present in gene-transfer units can spread in nature with consequences for human health and the evolution of environmental microbiota that are largely ignored. 相似文献
998.
999.
Badgers prefer cattle pasture but avoid cattle: implications for bovine tuberculosis control 下载免费PDF全文
Rosie Woodroffe Christl A. Donnelly Cally Ham Seth Y. B. Jackson Kelly Moyes Kayna Chapman Naomi G. Stratton Samantha J. Cartwright 《Ecology letters》2016,19(10):1201-1208
Effective management of infectious disease relies upon understanding mechanisms of pathogen transmission. In particular, while models of disease dynamics usually assume transmission through direct contact, transmission through environmental contamination can cause different dynamics. We used Global Positioning System (GPS) collars and proximity‐sensing contact‐collars to explore opportunities for transmission of Mycobacterium bovis [causal agent of bovine tuberculosis] between cattle and badgers (Meles meles). Cattle pasture was badgers’ most preferred habitat. Nevertheless, although collared cattle spent 2914 collar‐nights in the home ranges of contact‐collared badgers, and 5380 collar‐nights in the home ranges of GPS‐collared badgers, we detected no direct contacts between the two species. Simultaneous GPS‐tracking revealed that badgers preferred land > 50 m from cattle. Very infrequent direct contact indicates that badger‐to‐cattle and cattle‐to‐badger M. bovis transmission may typically occur through contamination of the two species’ shared environment. This information should help to inform tuberculosis control by guiding both modelling and farm management. 相似文献
1000.
保护行为学: 正在兴起的保护生物学分支学科 总被引:4,自引:0,他引:4
过去的30年里, 人们利用动物行为的进化生物学方法来解决保护实践中遇到的问题, 行为学、行为生态学与保护生物学相结合, 产生了保护生物学的一个新分支学科--保护行为学。保护行为学的研究目的是: 从物种保护实践中发现环境对动物行为的影响以及行为的生态适应性, 并把动物行为学和行为生态学理论应用到物种保护实践中, 从而促进物种保护工作。目前全球有10%的物种濒临灭绝, 生物多样性保护日趋紧迫, 保护行为学的诞生为行为学和保护生物学研究带来了新的机遇, 也表明行为学家和保护生物学家正在担负起挽救濒危物种的使命。不久的将来, 保护行为学及其相关学科将更加繁荣。 相似文献