The value of biodiversity experiments

Recent biodiversity experiments have investigated the relationship between diversity and ecosystem functioning by synthesizing plant communities from pools of species that have been experimentally manipulated to vary numbers and types of species present while holding abiotic factors constant. Biodiversity experiments therefore focus on a previously under-explored aspect of global change: the feedback from diversity to environment. Consequences of random manipulation of species communities may not correspond well to those of specific extinction sequences observed in the past in response to extinction drivers that cause highly non-random loss. However, random manipulation provides a good starting point given that existing communities could undergo many alternative orders of species loss in the future in response to a variety of different potential extinction drivers. Further, the effects of some extinction drivers are currently poorly understood and therefore difficult to predict (e.g. climate change) and it may be premature to dismiss the predictions of random scenarios as irrelevant to all real examples of species loss. The first generations of biodiversity experiments have provided valuable, and sometimes unexpected, discoveries about the general nature of the relationship between diversity and ecosystem functioning. These discoveries could not have been made using observational studies. We propose that different examples of extinction loss in the real or a potential future world form a continuum from situations where the results of the first-generation biodiversity experiments will be highly relevant to less relevant. At the one extreme are examples where the effects of biodiversity on ecosystem functioning will be overwhelmed by direct effects of the extinction driver on processes (e.g. chronic eutrophication). At the other extreme are situations where ecosystem processes are not strongly affected by direct effects of the extinction driver and where the effects of species loss on functioning may be more important (e.g. habitat fragmentation). Given the unprecedented uncertainty about the future of biodiversity and the functioning of ecosystems, a general approach with randomly varying species pools was the right place to start in order to provide a general foundation. The new challenge is to test for effects of biodiversity on functioning in real-world examples of species loss.

Zusammenfassung

Biodiversitätsversuche zeichnen sich dadurch aus, dass natürliche Artenpools experimentell reduziert werden und anschließend der Zusammenhang zwischen der Artenzahl und Ökosystemfunktionen unter konstanten abiotischen Umweltbedingungen untersucht wird. Dadurch unterscheiden sich Biodiversitätsexperimente grundsätzlich von anderen Versuchen, die die Biodiversität als Zielvariable behandeln und stattdessen die abiotische Umwelt manipulieren. Die Auswahl der Arten für die reduzierten Artenpools in Biodiversitätsexperimenten erfolgte bisher meist zufällig, während natürliche Aussterbefaktoren wie Eutrophierung nicht alle Arten gleichermassen gefährden. Für verschiedene Aussterbefaktoren ist aber so wenig bekannt, dass ein zufälliges Aussterbeszenario die beste gegenwärtig verfügbare Option ist. Dies trifft insbesondere für mögliche zukünftige Aussterbeprozesse zu, die durch globale Umweltveränderungen (Klima, biologische Invasionen) oder Habitatsfragmentierung ausgelöst werden könnten. Die erste Generation von Biodiversitätsexperimenten mit zufälligen Aussterbeszenarien hat wertvolle, teilweise unerwartete, generelle Zusammenhänge zwischen Artenzahl und Ökosystemfunktionen aufgedeckt. Diese Zusammenhänge ließen sich durch vergleichende Studien nicht erkennen. In Zukunft sollten Biodiversitätsexperimente dennoch vermehrt Aussterbeszenarien simulieren, die in der realen Umwelt mit größter Wahrscheinlichkeit auftreten.     

Morava River alluvial meadows on the Slovak–Austrian border (Slovak part): plant community dynamics, floristic and butterfly diversity – threats and management

The Morava river forms a border 71 km in length between Slovakia and Austria. Along this stretch of river is the largest complex of flooded grasslands in Central Europe, most of which lays on the Slovak side. Most of the grasslands belong to the subcontinental vegetation alliance Cnidion, with smaller areas of Alopecurion and Molinion. The grasslands are biotopes of many endangered plant and animal species. The influence of water regime dynamics on species composition have been studied since 1992 along permanent transects. The results of studies on the relation between water regime dynamics, vegetation and soils on the whole section of the Morava River floodplain are presented.     

生态系统管理的概念及其要素

生态系统管理起源于传统的自然资源管理和利用领域,形成于本世纪９０年代。它是指基于对生态系统组成、结构和功能过程的最佳理解,在一定的时空尺度范围内将人类价值和社会经济条件整合到生态 营中,以恢复或维持生态系统整体性和可持续性。生态系统管理要求收集被管理系统核心层次的生态学数据并监测生态系统的变化过程。生态系统管理的要素包括：有明确的管理目标,有确定的系统边界昨单元,基于对生态 深刻理解,有适宜的尺度     

Optimal invasive species management under multiple uncertainties

The management programs for invasive species have been proposed and implemented in many regions of the world. However, practitioners and scientists have not reached a consensus on how to control them yet. One reason is the presence of various uncertainties associated with the management. To give some guidance on this issue, we characterize the optimal strategy by developing a dynamic model of invasive species management under uncertainties. In particular, focusing on (i) growth uncertainty and (ii) measurement uncertainty, we identify how these uncertainties affect optimal strategies and value functions. Our results suggest that a rise in growth uncertainty causes the optimal strategy to involve more restrained removals and the corresponding value function to shift up. Furthermore, we also find that a rise in measurement uncertainty affects optimal policies in a highly complex manner, but their corresponding value functions generally shift down as measurement uncertainty rises. Overall, a rise in growth uncertainty can be beneficial, while a rise in measurement uncertainty brings about an adverse effect, which implies the potential gain of precisely identifying the current stock size of invasive species.     

Autonomic resource management in virtualized data centers using fuzzy logic-based approaches

Data centers, as resource providers, are expected to deliver on performance guarantees while optimizing resource utilization to reduce cost. Virtualization techniques provide the opportunity of consolidating multiple separately managed containers of virtual resources on underutilized physical servers. A key challenge that comes with virtualization is the simultaneous on-demand provisioning of shared physical resources to virtual containers and the management of their capacities to meet service-quality targets at the least cost. This paper proposes a two-level resource management system to dynamically allocate resources to individual virtual containers. It uses local controllers at the virtual-container level and a global controller at the resource-pool level. An important advantage of this two-level control architecture is that it allows independent controller designs for separately optimizing the performance of applications and the use of resources. Autonomic resource allocation is realized through the interaction of the local and global controllers. A novelty of the local controller designs is their use of fuzzy logic-based approaches to efficiently and robustly deal with the complexity and uncertainties of dynamically changing workloads and resource usage. The global controller determines the resource allocation based on a proposed profit model, with the goal of maximizing the total profit of the data center. Experimental results obtained through a prototype implementation demonstrate that, for the scenarios under consideration, the proposed resource management system can significantly reduce resource consumption while still achieving application performance targets.

The cumulative effects of resource development on biodiversity and ecological integrity in the Peace-Moberly region of Northeast British Columbia,Canada

Rapid acceleration of industrial development in north-eastern British Columbia is currently occurring without a comprehensive assessment of the effects it will have on ecological or cultural systems. The cumulative effects of past development are already being felt within the Treaty 8 First Nations of the region but these effects have not been quantified from a landscape point of view. Using habitat modeling and GIS analysis the effects of 35 years of agricultural and industrial development on forest biodiversity and ecological integrity were investigated for a 410,000 ha landscape in north-eastern British Columbia. The study identified a significant increase in area impacted by developments which lead to a shift in landscape structure and significant change in forest biodiversity. Forest fragmentation and habitat loss has resulted in an increase in open, early seral and edge habitats at the expense of contiguous mature forests. The change in landscape structure resulted in a significant increase in species richness as generalist and early seral species responded positively to increases in these habitats. A significant increase in brown-headed cowbird parasitism risk was also detected. Changes in landscape structure, reduction in habitat for 22% of modeled species, increase parasitism and predation risk due to fragmentation, and increased access have resulted in a cumulative effect of recent resource development on ecological integrity that is both additive and synergistic. The propose acceleration of future development will increase the risk to maintaining the biodiversity and ecological integrity in the Peace-Moberly region of British Columbia.     

Line thinning enhances diversity of Coleoptera in overstocked Cryptomeria japonica plantations in central Japan

We evaluated the effectiveness of line thinning, a new silvicultural technique, toward restoring diversity of Coleoptera in overstocked Cryptomeria japonica D. Don plantations in central Japan. We compared the abundance of some common Coleoptera families between line-thinned stands and adjacent unthinned stands in two plantations: low-elevation Sugi site (4 years since thinning) and high-elevation Kuchiotani site (6 years since thinning). Many bettle families comprising various functional groups such as plant feeders, wood borers, rotten wood feeders, root feeders, fungus feeders, dung feeders, and scavengers were more abundant in the line-thinned stands than in the unthinned stands. Furthermore, some important families were missing from the unthinned stands. There were strong positive relationships between Coleopteran abundance and understory vegetation. Our results suggest that line thinning may potentially increase biodiversity in overstocked C. japonica plantations by restoring important ecological processes such as food-web interactions (pollination, predation, herbivory, decomposition, parasitism, etc.), and habitat conditions.     

A hierarchical approach to ecosystem assessment of restoration planning at regional,catchment and local scales in Japan

A hierarchical approach to restoration planning at the regional, catchment and local scales is proposed and examined. Restoration projects limited to a local scale and focused on habitat improvement for individual species ended in failure, which has led to the recognition that there is a need for ecosystem-based management at the landscape level. The first landscape-level restoration in Japan is under way in the Kushiro and Shibetsu River Basins, in northern Japan. However, public consensus on these large-scale restoration projects has not yet matured and there are very few projects that have progressed even as far as mapping to classify intact and disturbed ecosystems. Classification of habitat quality using physical and biological indicators appears to be the core element of analysis of ecological degradation at the regional scale (100–1,000 km²). This mass-screening process is critical to identify areas in potential need of restoration. The causes and mechanisms of ecosystem degradation are then examined at the catchment scale (10–100 km²) by linking material flows and habitat conditions. Direct environmental gradient analysis is useful to determine cause and effect relationships between species and habitat quality. Finally, we recommend implementation of field experiments with a clear hypothesis at the local scale (0.01–1 km²). At this stage, key variables causing degradation of the target ecosystem are manipulated to verify the hypothesis. Based on the results of local-scale analyses, the possibility of restoration success can be evaluated, which directs us to practical schemes for future restoration projects at larger scales.     

On the use of hybrid reinforcement learning for autonomic resource allocation

Reinforcement Learning (RL) provides a promising new approach to systems performance management that differs radically from standard queuing-theoretic approaches making use of explicit system performance models. In principle, RL can automatically learn high-quality management policies without an explicit performance model or traffic model, and with little or no built-in system specific knowledge. In our original work (Das, R., Tesauro, G., Walsh, W.E.: IBM Research, Tech. Rep. RC23802 (2005), Tesauro, G.: In: Proc. of AAAI-05, pp. 886–891 (2005), Tesauro, G., Das, R., Walsh, W.E., Kephart, J.O.: In: Proc. of ICAC-05, pp. 342–343 (2005)) we showed the feasibility of using online RL to learn resource valuation estimates (in lookup table form) which can be used to make high-quality server allocation decisions in a multi-application prototype Data Center scenario. The present work shows how to combine the strengths of both RL and queuing models in a hybrid approach, in which RL trains offline on data collected while a queuing model policy controls the system. By training offline we avoid suffering potentially poor performance in live online training. We also now use RL to train nonlinear function approximators (e.g. multi-layer perceptrons) instead of lookup tables; this enables scaling to substantially larger state spaces. Our results now show that, in both open-loop and closed-loop traffic, hybrid RL training can achieve significant performance improvements over a variety of initial model-based policies. We also find that, as expected, RL can deal effectively with both transients and switching delays, which lie outside the scope of traditional steady-state queuing theory.

Contrasting demography of two Patagonian shrubs under different conditions of sheep grazing and resource supply

Summary Two shrub species, dominant in western Patagonia, Argentina, exhibited different demographic behaviors under the effect of sheep grazing and of manipulated resource levels. Senecio filaginoides showed an increase in cover under increasing grazing pressures; the rise was explained by an increasing number of individuals and not by larger plants; this trend was reversed when no grazing took place. Mulinum spinosum showed a slight decrease in cover and density at increasing grazing pressures, and no change in plant size. In a field experiment in which water was added (30 mm in early summer) and the dominant grasses removed, both factors substantially augmented the number of 1-year-old seedlings of Senecio recruited; the only noticeable response of Mulinum was an increase in seedling emergence because of grass removal. Six years after this last treatment, Senecio exhibited a ten fold increase in density, and its population structure showed a peak in younger classes; Mulinum remained unaffected. In seedling surveys conducted within an exclsure and in its surroundings, the emergence of Senecio was similar in these areas in the two years of the study, whereas the emergence of Mulinum was higher inside the exclosure for one of the years. The emergence of Senecio in the wetter year was 3 times larger than in the drier one. Grazing did not affect first-year survival of any species; the major source of seedlign death in this case, as well as in the manipulative experiment, was desiccation during summer drought. We conclude that the contrasting responses of the two species to grazing are mostly due to the greater ability of Senecio to benefit from any increase in resources, including those not used by grazed plants. The difference might also be due to a reduction in the seed availability of Mulinum caused by sheep preference for its fruits. The dissimilar abilities of the two shrubs to employ the resources freed by grazing would derive more from their contrasting demographic potential (i.e. the ability to rapidly increase biomass/m²) than from a difference in their niche overlap with palatable species.     

A study of spatial variability of domoic acid in razor clams: recommendations for resource management on the Washington coast

Domoic acid (DA) levels in Washington State razor clams (Siliqua patula) have been extremely variable and unpredictable, resulting in emergency closures of harvest areas in 1991, 1998, and 1999. Information concerning toxin variability relative to sampling location is important in developing a more reliable plan for managing DA outbreaks. In November 1998, record levels of DA in razor clams (up to 295 ppm) were reported at Kalaloch beach, Washington. A razor clam resource survey conducted there during the summer of 1999, along with the long retention time of DA in the clams, permitted a study of DA levels as a function of tidal elevation and north-south beach location. During the summer low tides (28–31 July 1999) razor clams were collected from six east-west transects, approximately 1.6 km apart. Each clam was individually analyzed for DA to determine the distribution of toxin between (interspecific variability) and within (intraspecific variability) transects. While average DA levels were similar between transects, toxin levels varied substantially among individual clams. The coefficient of variation among all samples (n=445) was 122%, indicating that harvest closures based upon composite analyses of only six clams could be in error. Here we recommend a sampling strategy of razor clams for regulatory purposes that will result in DA measurements more representative of total population toxin values.     

The role of community-based wild resource management in Zimbabwe

Wildlife was in decline in Zimbabwe while the resource was being managed centrally by the State in terms of conventional protectionist legislation. The legislation was changed in 1960 and this led to cautious institutional reforms, whereby responsibility for wildlife was gradually devolved to landholders who were encouraged to use it profitably. This was achieved without the State abrogating its ultimate responsibility for the wellbeing of the resource.The CAMPFIRE programme was a response to the particular requirements of communally managed wild resources. Successful implementation required that appropriate institutions were in place. These allowed the peasants a meaningful say in the management of their wildlife and permitted them to use it profitably to generate a sufficient incentive to persuade them to conserve the resource on their land. As on large-scale commercial ranches, socio-economic factors proved more significant than ecological considerations in preserving wildlife on communally occupied land that is representative of much of Africa and the Third World.Former Director of National Parks and Wild Life Management, Zimbabwe.     

The reliability of product-specific eco-labels as an agrobiodiversity management instrument

This paper seeks to understand why multinationals prefer to launch a label specific to their own product and examines how reliable these product-specific eco-labels are. A new methodology is applied to assess the extent to which eco-labels live up to claims about their contribution to conservation and the sustainable use of agricultural biodiversity. Product-specific eco-labels are considered as industry self-regulation and all three regulatory stages are studied: the planning, implementation and outcome stage. There are major differences between the product specific eco-labels in the degree in which agrobiodiversity management is part of the normative labeling schemes. Although there are some problems of reliability, such as transparency in the implementation stage and the monitoring in the outcome stage, the degree of reliability of product-specific labels is comparable with eco-labels of international labeling families. The conclusion is that only one of the product-specific eco-labels examined here is reliable when examined in the light of all three stages. The main reason why multinationals establish a product-specific eco-label instead of adopting one from an existing labeling family is that they want to profile themselves as distinct from other companies. The unique character of a product-specific label creates a market opportunity for them.     

Power and performance management of virtualized computing environments via lookahead control

There is growing incentive to reduce the power consumed by large-scale data centers that host online services such as banking, retail commerce, and gaming. Virtualization is a promising approach to consolidating multiple online services onto a smaller number of computing resources. A virtualized server environment allows computing resources to be shared among multiple performance-isolated platforms called virtual machines. By dynamically provisioning virtual machines, consolidating the workload, and turning servers on and off as needed, data center operators can maintain the desired quality-of-service (QoS) while achieving higher server utilization and energy efficiency. We implement and validate a dynamic resource provisioning framework for virtualized server environments wherein the provisioning problem is posed as one of sequential optimization under uncertainty and solved using a lookahead control scheme. The proposed approach accounts for the switching costs incurred while provisioning virtual machines and explicitly encodes the corresponding risk in the optimization problem. Experiments using the Trade6 enterprise application show that a server cluster managed by the controller conserves, on average, 22% of the power required by a system without dynamic control while still maintaining QoS goals. Finally, we use trace-based simulations to analyze controller performance on server clusters larger than our testbed, and show how concepts from approximation theory can be used to further reduce the computational burden of controlling large systems.

The emergy of metabolism in different ecosystems under the same environmental conditions in the agro-pastoral ecotone of northern China

The sustainability of ecosystem productivity and rules governing ecosystem development are important topics of scientific research. The emergy approach is an effective method for investigating these topics, especially when used to evaluate systems that have developed under the same environmental conditions, such as climate and soil. In this paper, emergy differences between terrestrial ecosystems were studied in Guyuan County, a region representative of the agro-pastoral ecotone in Hebei Province, China. A combination of field tests and a questionnaire survey were carried out between June and August 2015. The ecosystems studied included natural grassland, artificial grassland, field crops and commercial crops. These four ecosystems were further subdivided into a total of ten ecosystems. Natural grassland was divided into free-grazing and mowed ecosystems; artificial grassland consisted of oat, Chinese leymus and corn silage; field crops included naked oats, flax and wheat; and commercial crops consisted of cabbage and potatoes. The results showed that the rain input of 4.78 × 10¹⁴ seJ/ha/yr constituted the highest renewable natural resource emergy and that the purchased emergy inputs of the ten ecosystems ranged from 3.53 to 147.67 × 10¹⁴ seJ/ha/yr. Natural resource emergy input was the basic power to maintain the ecosystem, and purchased emergy input was the direct cause of the development of the ecosystems. Groundwater was the most important non-renewable purchased energy for the production of economic crops. The emergy investment ratios (EIR) for potatoes (27.81) and cabbage (19.03) were higher than those of the other ecosystems, but mowed and artificial Chinese leymus grassland had the higher emergy self-sufficiency rates (ESR). Natural grassland, artificial Chinese leymus grassland and traditional grain crops had a low environmental load and high sustainability, whereas potatoes and cabbage had a high environmental load and low sustainability. Overall, rain-fed artificial grassland has a high development potential from the perspective of environment and productivity.     

Individual optimization efforts and population dynamics: a mathematical model for the evolution of resource allocation strategies, with applications to reproductive and mating systems

We develop a formal framework for the optimal allocation of limited resources that includes and clarifies the interplay between individual optimization and the resulting effects at the population level. As an example, in regard to the evolution of sexual recombination, the paradox of the twofold cost of sex is avoided by distinguishing between the evolution of recombination and the subsequent emergence and stability of different mating types as a result of individual optimization within a population that benefits from recombination.