Life at the edge

Extremophiles: Microbial Life in Extreme Environments (1998). Koki Horikoshi and William D. Grant (Eds). Wiley-Liss, 311 pp. hardback; ISBN 0 471 02618 2 ($134.50)     

Nature conservation as if people mattered

The restoration of natural capital is arguably one of the most radical ideas to emerge in recent years as it links two imperatives whose exponents have been at loggerheads for decades. These are the need to protect biodiversity and conserve natural resources as espoused by conservationists and environmentalists, and the demand for natural resources as dictated by economists and society at large, at local, regional, national and international scales. We need to work together, or even ‘leap together’, across traditional disciplinary frontiers or polemical stances, in order to find innovative solutions that counter the prevailing ideological divide separating economics and ecology. We close this special issue with a proposition of five pillars and three principal tasks for sustainable living, including conservation and restoration.     

Changing attitudes in nature conservation: the Nature Conservancy and Nature Conservancy Council

An official organization responsible for ecological research and nature conservation was formed in 1949. This paper traces its development and vicissitudes, first as an independent Nature Conservancy, then as a part of the Natural Environment Research Council, and finally as the Nature Conservancy Council. Much has been achieved: ecology is now a household word; there is a strong voluntary tide for nature conservation in the country; and there have been notable achievements in practical conservation. But the dangers to nature in Britain have proved to be much greater than anticipated.     

Losing your edge: climate change and the conservation value of range‐edge populations

Populations occurring at species' range edges can be locally adapted to unique environmental conditions. From a species' perspective, range‐edge environments generally have higher severity and frequency of extreme climatic events relative to the range core. Under future climates, extreme climatic events are predicted to become increasingly important in defining species' distributions. Therefore, range‐edge genotypes that are better adapted to extreme climates relative to core populations may be essential to species' persistence during periods of rapid climate change. We use relatively simple conceptual models to highlight the importance of locally adapted range‐edge populations (leading and trailing edges) for determining the ability of species to persist under future climates. Using trees as an example, we show how locally adapted populations at species' range edges may expand under future climate change and become more common relative to range‐core populations. We also highlight how large‐scale habitat destruction occurring in some geographic areas where many species range edge converge, such as biome boundaries and ecotones (e.g., the arc of deforestation along the rainforest‐cerrado ecotone in the southern Amazonia), can have major implications for global biodiversity. As climate changes, range‐edge populations will play key roles in helping species to maintain or expand their geographic distributions. The loss of these locally adapted range‐edge populations through anthropogenic disturbance is therefore hypothesized to reduce the ability of species to persist in the face of rapid future climate change.     

Life at the leading edge

Cell migration requires sustained forward movement of the plasma membrane at the cell's front or "leading edge." To date, researchers have uncovered four distinct ways of extending the membrane at the leading edge. In lamellipodia and filopodia, actin polymerization directly pushes the plasma membrane forward, whereas in invadopodia, actin polymerization couples with the extracellular delivery of matrix-degrading metalloproteases to clear a path for cells through the extracellular matrix. Membrane blebs drive the plasma membrane forward using a combination of actomyosin-based contractility and reversible detachment of the membrane from the cortical actin cytoskeleton. Each protrusion type requires the coordination of a wide spectrum of signaling molecules and regulators of cytoskeletal dynamics. In addition, these different protrusion methods likely act in concert to move cells through complex environments in?vivo.     

Peatland archaeology: a conservation resource on the edge of extinction

The dichotomy between the Arts and Sciences has meant that much valuable information in terms of conservation strategies available from the archaeological record has tended to be ignored by the conservation bodies and pigeon-holing within science itself further leads to an ignorance of the palaeoecological record and its relevance. Similar charges can be levelled at archaeologists for their failure to understand the relevance of their research to the modern world. An attempt is made to draw these various strands together in terms of recent work in wetland archaeology and the development of raised mires and their conservation in Britain, with particular reference to the Humberhead Levels of South Yorkshire and adjoining counties. A plea for more effective dialogue and a joint approach is entered.     

The declining occurrence of moose (Alces alces) at the southernmost edge of its range raise conservation concerns

The border region between Austria, the Czech Republic, and Germany harbors the most south‐western occurrence of moose in continental Europe. The population originated in Poland, where moose survived, immigrated from former Soviet Union or were reintroduced after the Second World War expanded west‐ and southwards. In recent years, the distribution of the nonetheless small Central European population seems to have declined, necessitating an evaluation of its current status. In this study, existing datasets of moose observations from 1958 to 2019 collected in the three countries were combined to create a database totaling 771 records (observations and deaths). The database was then used to analyze the following: (a) changes in moose distribution, (b) the most important mortality factors, and (c) the availability of suitable habitat as determined using a maximum entropy approach. The results showed a progressive increase in the number of moose observations after 1958, with peaks in the 1990s and around 2010, followed by a relatively steep drop after 2013. Mortality within the moose population was mostly due to human interactions, including 13 deadly wildlife‐vehicle collisions, particularly on minor roads, and four animals that were either legally culled or poached. Our habitat model suggested that higher altitudes (ca. 700–1,000 m a.s.l.), especially those offering wetlands, broad‐leaved forests and natural grasslands, are the preferred habitats of moose whereas steep slopes and areas of human activity are avoided. The habitat model also revealed the availability of large core areas of suitable habitat beyond the current distribution, suggesting that habitat was not the limiting factor explaining the moose distribution in the study area. Our findings call for immediate transboundary conservation measures to sustain the moose population, such as those aimed at preventing wildlife‐vehicle collisions and illegal killings. Infrastructure planning and development activities must take into account the habitat requirements of moose.     

车八岭保护区及其邻近地区的木兰科植物种群及其保护现状

报道了广东省始兴县车八岭国家级自然保护区及其邻近地区木兰科植物种群特点及保护现状。木兰科植物通常位于人为破坏较轻 ,林相保存较好 ,以壳斗科、樟科、茶科为主要建群种的中亚热带常绿阔叶林中。共设置了 9个面积为 4 0 0 m2的样方。在样方中共记录了 3种木兰科植物 :观光木 ( Tsoongiodendron odor-um Chun)、深山含笑 ( Michelia maudiae Dunn)和金叶含笑 ( M.foveolata Merr.ex Dandy)。其中 ,深山含笑的种群较大 ,呈稳定结构 ,但主要局限于保护区内保护较好的地域 ;金叶含笑种群面临濒危 ,种群小 ,在保护区呈零星分布 ;观光木的分布区域相对较广 ,在保护区内外均见分布 ,但种群较小 ,特别是在保护区外的种群 ,由于人为的干扰 ,种群在急剧减少。大多数木兰科植物的种群在原生境均表现出自然更新不良 ,必须加以保护。分析了影响车八岭及其邻近地区木兰科植物种群及其群落发展的主要限制因素 ,建议加强自然保护知识的宣传和木兰科植物的人工保育 ,促进该区域木兰科植物资源的管理和发展     

国家公园首先是自然保护基地

<正>随着社会经济的不断发展,我国对自然保护工作的认识不断提高,行动的力度也不断加大。中国共产党第十八次全国代表大会报告首次将生态文明建设与经济建设、政治建设、文化建设、社会建设并列,提出了建设中国特色社会主义五位一体的总体布局。党的十八届三中全会决议中提出"严格按照主体功能区定位推动发展,建立国家公园体制"。为了落实中央的决定,国家林业局、云南省人民政府和世界自然保护联盟(IUCN)于2014年4月28日在昆明联合组织召开了"国家公园建设研讨会"。     

宁夏沙坡头国家自然保护区鸟类景观生态安全格局构建

随着宁夏沙坡头国家自然保护区的旅游发展与荒漠化进程,保护区内不同类型的鸟类均面临着日益增加的自然及人为干扰胁迫,鸟类群落的丰富度下降趋势显著。为了改善保护区内鸟类生物多样性现状,优化鸟类栖息地空间结构,基于现有鸟类调查与研究资料,筛选影响鸟类活动的各类阻力指数,建立鸟类活动最小累积阻力面,运用最小阻力模型构建景观生态安全格局。研究结果表明:源地面积为1690.67 hm~2,占保护区总体面积的12.09%;廊道共13条;辐射道共85条;战略点共8个;保护关键区面积为2634.48 hm~2,占保护区总体面积的18.76%。在此基础上,针对不同类型的重点保护地块、保护热点及栖息地之间的联系廊道提出鸟类保护的空间格局优化建议。详细梳理了阻力面模型的构建方法,改进了相关技术环节,为我国自然保护区生物多样性景观安全格局优化提供了科学的方法与实践指导。     

Nature conservation from a Junior High School perspective

Nature conservation has a higher probability of being successful when it is backed by public support. This is influenced by knowledge and values, many of which may derive from school curricula, experiments and activities. We implemented a study in a Portuguese Junior High School aiming to evaluate: (1) which factors influence how people subscribe reasons for conserving nature; (2) the criteria used to identify conservation priority species; and, (3) the proposed recovery measures for priority species. A survey of 91 students in a suburban area revealed that nature conservation was regarded as being more important than tourism or industry, but less than values related to public health. Students who have close contacts with wildlife and whose parents have higher education levels exhibited positive attitudes towards nature conservation, which seems to derive from exposure to information related to nature, in their home environment. The criteria chosen to identify conservation priority species and to select appropriate conservation measures indicate that they are likely to be influenced by the media. These results emphasise that the relationship between parental education levels and access to information is an important factor in shaping urban students’ attitudes towards nature conservation.     

Nature conservation: priority-setting needs a global change

The limited resources available for the conservation of biodiversity and ecosystem services call for prioritisation schemes. For instance, in the process of systematic conservation planning site selection is partly determined by efficiency gains. In this paper we present an alternative method for global spatial priority-setting based on ecological indicators, combined with social and economic conditions that influence the effectiveness of conservation, and measures for the long-term persistence of biodiversity. In the analysis the assumption made is that nature conservation should prioritize the effective maintenance of functional ecosystems that do not only provide the most ecosystem services but are also more likely to have a high adaptive capacity towards unavoidable environmental change. Furthermore, the effectiveness and permanence of conservation projects is tied to certain socioeconomic and political conditions that, as we suggest, should be evaluated as part of the conservation priority-setting process. We propose three new priority categories: eco-functionally wise (EcoWise), socioeconomically wise (SocioWise) and proactive allocation of conservation resources considering future climate change (ClimateWise) expressed as indices based on 16 different indicators. Analysing the combined effects of these three categories (EcoSocioClimateWise), in a spatially explicit way highlights the importance of tropical, subtropical but also some temperate and boreal forest areas all of which are characterized by high values of vegetation density, tree height and carbon storage. Our recommendations for policy makers prompt a shift in conservation planning towards advocating the use of ecological and socioeconomic indicators in combination with proxies for the vulnerability to future climate change impacts.     

Actin crosslinking proteins at the leading edge

The lamellar membrane at the leading edge of motile cells participates in a series of complex movements that involve the assembly and reorganization of actin bundles and networks, both structures formed by actin crosslinking proteins. Immunofluorescence miscroscopy localizes within lamellipodia and filopodia several crosslinking proteins including fascin, fimbrin, α-actinin and filamin. While these proteins may organize actin into bundles and networks, fimbrin and α-actinin may play an additional role of linking the cytoskeleton to cell-substratum adhesion sites.     

Darwin at the edge of the visible universe

Simon Conway Morris marvels at the perfection of sensory organs: shaped by eons of evolution, they can detect a single photon or an individual molecule. Only scientific instruments are able to reach beyond the limits of nature''s detectors.“Sans teeth, sans eyes, sans taste, sans everything”, observes Shakespeare''s Jaques bitterly in As You Like It. Today, we might bristle with prosthetics that keep our senses ticking along, but unless your job as a fighter pilot or tea specialist depends on 20/20 vision or subtle taste, then for the most part lack of acuity in our senses passes largely unremarked. It was not always so. For much of human history, defects in seeing, hearing or smelling the sabre-tooth tiger had irreversible consequences. One does not have to subscribe to the Rousseauean notion of the ‘noble savage'' to appreciate the example of the native Tierra del Fuegians Jemmy Button and York Minster—returning to their homeland on the Beagle—delighting in pointing out distant ships that none of the English crew could see until a telescope was hoisted to their less acute eyes.Charles Darwin, of course, opened the door to understanding the evolution of sensory systems, but perhaps there is one aspect of this particular Darwinian mantra that deserves a re-examination. By definition, sensory systems are functional: photons demand eyes, wafting molecules olfactory surfaces, and pressure waves ears. Equally fascinating are those sensory modalities that are entirely alien to human perception: echolocation, electro-communication, infrared sensation and even ultraviolet vision. Unsurprisingly, they have all independently evolved many times, reinforcing the Darwinian concept of adaptation. Yet each also represents a customized, jury-rigged contraption, using whatever happens to be at hand. Think of the multiple co-option of crystallins in eyes; infrared detectors in insects are probably derived from cuticular mechanoreceptors and, more confidently, we can trace the lineage of the electric organs of fish from their musculature.These sensory devices may be contraptions, but they have nevertheless evolved repeatedly to interpret the limits of the physical universe. As an example, consider the epitome of Darwinian analysis: the cameraeye. Much has been made, rightly so, of the ease with which it has evolved; whether by co-opting proteins such as opsins and the crystallins, or the unremarkable transition from the simple spot eye in a flatworm to the cryptic intelligence with which the blue-whale views its world. Might there be a less-considered perspective? The shift in refractive indices across the lens corrects almost perfectly for its spherical aberration (Jagger & Sands, 1999), but the retina can also detect single photons. In comparison to the camera eye, the compound version is unavoidably deficient, but this does not prevent some insects flying by starlight. In the re-tellings of the story of how eyes evolve, perhaps we have lost sight of Darwin''s somewhat mischievous rumination on the perfection of the eye. His straw-man conceals the fact that not only do eyes evolve, but they might be as near to perfect as they ever will be.And what about the other senses? The olfactory systems of insects and mammals are startlingly similar, and the former can detect a single molecule. In audition, the sensitivity of the male mosquito antenna is such that it is triggered by an infinitesimal deflection, equivalent to the top of the Eiffel Tower moving less than 1 mm (Göpfert & Robert, 1999). For vertebrates, the sensitivity of the transduction process in the inner ear is close to that of thermal noise (Denk & Webb, 1989). This represents an absolute barrier not only for biology, but also for the eye and nose; a photon or a molecule are the irreducible limits of detection.This is not to say that all sensory systems are equally acute; the echolocation skills of bats or the sensitivity of snakes to infrared radiation clearly show the extent of sensory capacities and sensitivities. However, in horseshoe bats, the exceptional tuning of the ear to specific frequencies—notably with an acoustic fovea in the cochlea and specific neural organization in the auditory cortex (Neuweiler 1990)—suggests that the limits of perception are close, or have perhaps been reached in existing lifeforms. Such extraordinarily fine-tuned sensitivities are also found in the infrared apparatus of crotalid snakes, which have facial pits that behave similarly to pinhole camera-eyes, and can detect minute temperature differences (Bakken & Krochmal, 2007).There is a further insight. Whilst infrared detectors have evolved in many snakes, insects and mammals, the system in the crotalids—and also that found independently in the beetle Acanthocnemus (Kreis et al, 2005)—is a bolometer: a thin sheet of highly vascularized tissue, suspended in an insulated cavity. Astronomers, as well as others, use analogous systems. Such convergence between evolution and technology is not surprising, and is further exemplified by the similarities between the fibre-optic systems of some siliceous sponge spicules and telecommunications technologies (Aizenberg et al, 2004). Biology has reached the edges of the physical universe, but scientific instruments allow us to see deeper, not least into the mysterious world of quantum physics. Without such instruments we would be blind, but we should remember that the way that cognitive processes allow us to understand a universe that is largely beyond our Darwinian senses, remains deeply enigmatic.