共查询到20条相似文献,搜索用时 15 毫秒
1.
During the last 20 years recombinant biotechnology has resulted in the development of organisms with unique genetic compositions,
some of which are for intentional release to the environment. While concerns have been raised that such organisms may be capable
of inducing transient unintended environmental effects, longer-term perturbations to soil processes and non-target species
effects have yet to be demonstrated. In parallel with the growth of the commercial biotechnology industry has come a significant
growth in regulatory review processes intended to evaluate the risks of these GMO products. Under the Toxic Substances Control
Act (TSCA), certain new microbial products that undergo pre-manufacture review are examined for human and environmental risks
using data and other information received in accordance with the U.S. Environmental Protection Agency’s (EPA’s) “Points to
Consider” guidance document. In the risk assessment process, carried out under the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA) and the Federal Food, Drug and Cosmetic Act (FFDCA) authorities, EPA evaluates both microbial pesticide products
and plants with pesticidal properties to determine if Federal safety standards are met. For all pesticide products, including
genetically engineered pesticides, EPA receives testing of product composition and chemical properties, human health effects,
environmental effects on non-target pests, and the fate of the pesticide in the environment. The EPA’s Office of Research
and Development supports risk assessment research related to such GMO products. This paper focuses on relevant EPA research
and regulatory examples related to soil effects considerations for GMOs. 相似文献
2.
Charles W. Fowler 《Biodiversity and Conservation》2008,17(4):841-855
Numerous global changes—notably anthropogenic extinction—force reconsideration of our management practices and the ways we
regulate human influence in today’s world. Here, I define management to maximize biodiversity and illustrate the science that
provides information to set goals for such management. Maximizing biodiversity simultaneously achieves sustainability and
systemic health by avoiding the abnormal or pathological. The normal or sustainable are determined through the use of empirical
integrative patterns to objectively account for the complexity of systems within which we find ourselves as a species. The
science that reveals these integrative patterns provides measures of problems that can be solved by maximizing biodiversity—problems
heretofore recognized only qualitatively. I use the Shannon-Weiner information index to test, and, with no surprise, reject
the null hypothesis that there is no direct anthropogenic effect on biodiversity. The results of this science serve as examples
of the kind of information most useful for guiding management and illustrate maximized biodiversity as a standard for management.
Reference points based on maximized biodiversity are preferable to statistical parameters in meeting the objective of avoiding
the abnormal or pathological in our interactions with other species, ecosystems and the biosphere. Management to maximize
biodiversity is implemented by modifying human interactions with other biotic systems to achieve consistency in such interactions
by mimicking natural role models of sustainability. Human influence is a significant factor in today’s world and the magnitude
of such influence is illustrated by comparing humans with other species. 相似文献
3.
Jonathan J. Buonocore Kathleen F. Lambert Dallas Burtraw Samantha Sekar Charles T. Driscoll 《PloS one》2016,11(6)
Reducing carbon dioxide (CO2) emissions from power plants can have important “co-benefits” for public health by reducing emissions of air pollutants. Here, we examine the costs and health co-benefits, in monetary terms, for a policy that resembles the U.S. Environmental Protection Agency’s Clean Power Plan. We then examine the spatial distribution of the co-benefits and costs, and the implications of a range of cost assumptions in the implementation year of 2020. Nationwide, the total health co-benefits were $29 billion 2010 USD (95% CI: $2.3 to $68 billion), and net co-benefits under our central cost case were $12 billion (95% CI: -$15 billion to $51 billion). Net co-benefits for this case in the implementation year were positive in 10 of the 14 regions studied. The results for our central case suggest that all but one region should experience positive net benefits within 5 years after implementation. 相似文献
4.
Juliette C. Young Mariella Marzano Rehema M. White David I. McCracken Steve M. Redpath David N. Carss Christopher P. Quine Allan D. Watt 《Biodiversity and Conservation》2010,19(14):3973-3990
Conflicts between the conservation of biodiversity and other human activities occur in all habitats and can impact severely
upon socio-economic and biological parameters. In a changing environment, with increasing pressure on ecosystem goods and
services and increasing urgency for biodiversity conservation, these conflicts are likely to increase in importance and magnitude
and negatively affect biodiversity and human well-being. It is essential, however, to better understand what is meant by ‘biodiversity
conflicts’ in order to develop ways to manage these effectively. In view of the complexity of the social and ecological contexts
of conflicts, this paper explores ‘biodiversity impacts’ linked to agricultural, forestry and other sectoral activities in
the UK. The paper then describes the transition from ‘biodiversity impacts’ to ‘biodiversity conflicts’, illustrating this
concept with specific examples. While generalisations relating to conflict management are made difficult by their unique contextual
settings, this paper suggests approaches for their management, based on the experiences of scientists who have been involved
in managing conflicts. We consider the role of science and scientists; trust and dialogue; and temporal and spatial scales
in biodiversity conflicts and highlight the combined role they play in successful biodiversity conflict management. Recommendations
are also made for future research on biodiversity conflicts in a changing environment. 相似文献
5.
Jeffrey Morris Jennifer Bagby 《The International Journal of Life Cycle Assessment》2008,13(3):226-234
Background, Aims and Scope
Measuring Environmental Value for Natural Lawn and Garden Care Practices provides a life cycle assessment and impacts valuation methodology to quantify environmental (public health and ecological)
and water conservation benefits from natural lawn and garden care practices in Seattle. Seattle Public Utilities (SPU) initiated
this study as part of a triple-bottom-line analysis of its Natural Lawn and Garden Care program.
Methods The study uses life cycle assessment (LCA) methods, including the Carnegie-Mellon Economic Input-Output Life Cycle Assessment
(EIOLCA) tool publicly available on the Internet, to inventory pollutant generation from a synthetic nutrients and pesticide
approach to lawn and garden care compared against a natural/organic care approach. The study applies US Environmental Protection
Agency’s TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts) climate change, acidification,
eutrophication, and human health-criteria air pollutant stressor factors, along with the Lawrence Berkeley National Laboratory’s
CalTOX risk assessment model’s human and ecosystem toxicity potentials to roll up the numerous pollutant quantities into six
environmental impact categories (global warming potential, human respiratory disease potential, human toxicity potential,
ecological toxicity potential, acidification potential and eutrophication potential). The study develops cost valuation estimates
for each impact category to produce a dollar estimate of the environmental cost of the two archetypical lawn and garden care
methods.
Results Lawns and gardens account for 25% of Seattle’s land area, so lawn and garden care methods potentially have substantial impacts
on the city’s land-and water-based ecosystems. LCA methods provide an informative methodology for comparing environmental
impacts from lawn and garden care practices. These methods reveal the importance of more natural lawn and garden care practices.
They also show that resource extraction and manufacturing impacts of pesticides and synthetic fertilizers dominate their on
site use impacts in the case of global warming, but that the reverse holds for human and ecological toxicity, and eutrophication.
In addition, releases of particulates, SOx and NOx associated with gasoline-powered lawn mowing are nearly an order of magnitude larger than releases of these pollutants as
a result of the production of pesticides and fertilizers.
Discussion The study proceeds by using available data and research to build a desktop model that characterizes and contrasts two archetypical
lawn and garden care practices: (1) Petroleum-based fertilizers and pesticides, a gasoline-powered lawn mower, and substantial
irrigation to maintain a traditional weed-free, always-green lawn and garden, versus (2) A backyard compost system to provide
lawn and garden nutrients, supplemented moderately by purchased non-synthetic soil amendments, an electricity-powered mower,
no pesticides, and drought tolerant lawn and garden species having little need for irrigation.
Conclusions The study concludes that each household converting from synthetic to natural practices produces nearly $75 in annual ongoing
public health, ecological, water conservation and hazardous waste management benefits — between $16 and $21 of environmental
benefits from reduced use of synthetic fertilizers and pesticides, $8 of environmental benefits for switching from gas to
electricity for lawn mowing, $42 in cost savings due to reduced irrigation, and $5 or $6 from lower hazardous waste management
costs. There also is a potential one time avoidance of $31 in construction costs resulting from reduced need for storm water
detention and diversion capacity.
Recommendations and Perspectives This study’s estimates of environmental value would benefit from comprehensive information on direct exposure to active ingredients
in insecticides during their application. Estimates of impacts are based only on volatilization and runoff of active ingredients
after application. Furthermore, the study would benefit from estimates of carbon sequestration in soils promoted by natural
lawn and garden care techniques, and on the upstream pollutant releases from production of synthetic versus organic fertilizers.
All three of these data gaps suggest that the estimated $75 per single family residence for environmental value is probably
a lower bound on benefits from natural lawn and garden care versus more traditional pesticide-and-synthetic-fertilizer-based
approaches.
ESS-Submission Editor: Mary Ann Curran (curran.maryann@epa.gov) 相似文献
6.
Clive Nettleton Carolyn Stephens Fiona Bristow Susan Claro Thomas Hart Caroline McCausland Ingrid Mijlof 《EcoHealth》2007,4(4):461-471
This article reports previously unpublished results of a collaborative study undertaken in 2003 by health workers of the UK-based
organisation Health Unlimited, and by researchers of the London School of Hygiene and Tropical Medicine. This study marked the first of a series of collaborative activities aimed at highlighting the situation of Indigenous peoples,
some in the most isolated ecosystems of the planet. While many researchers focus on quantitative analysis of the health and
environmental conditions of Indigenous peoples, our 2003 study aimed at exploring the views of Indigenous peoples in isolated
communities in five countries on their environment and their health. In this article we look closely at the web of knowledge
and belief that underpins Indigenous peoples’ concepts of health and well-being, and their relationship to land and the environment.
Although many Indigenous people have been forced off their traditional lands and live in rural settlements, towns, and cities,
there are still a large number of people living in very small Indigenous communities in remote areas. This article focuses
on 20 such communities in six countries. We explore traditional knowledge and practice and its relationship to Western medicine
and services. The research findings highlight the importance of Indigenous knowledge systems for the emerging ecohealth community
and suggest that we have much to learn from Indigenous peoples in our pursuit of a more holistic science.
Utz Wachil is from the K’iche language originating in Totonicapan Department, Guatemala. It translates literally as “fine/well
face-ness,” face meaning one’s aspect in general, not only physical appearance. 相似文献
7.
Studies of well-being have been dominated by perspectives that stem from Western, health-science notions of individual’s health
and psychological development. In recent times, however, there has been a developing sensitivity to the cultural and place-specific
contexts affecting the health and well-being of contrasting populations in different environments. Drawing on these advances,
this article explores the potential in conceptualizing a place-based notion of well-being that recognizes the cultural and
environmental specificity of well-being for specific populations in a given setting. We argue that a geographical approach
to well-being enables the linking of culture and environment for future indigenous research into both ecosystems and human
health. Taking the case of an indigenous population, we identify the contexts that affect Maori well-being and we argue that
key sociocultural and environmental dimensions need to be integrated for a culturally appropriate approach to Maori well-being. 相似文献
8.
John N. Kittinger Kristopher M. Coontz Zhanpeng Yuan Deju Han Xianfu Zhao Bruce A. Wilcox 《EcoHealth》2009,6(4):601-613
A significant challenge exists in assessing the social and ecological impacts of development projects in a holistic and comprehensive
manner. Our objective is to elucidate the linkages between ecological change and human well-being, and its importance in integrated
assessment policy for development projects, using the Three Gorges Dam (China) as a case study. A collaborative research initiative
was undertaken to review and synthesize published information on the ecological and human health effects of the Three Gorges
Dam. Our synthesis suggests that the Three Gorges Dam has altered social–ecological dynamics of human health and ecosystem
function in the Yangtze River basin with significant consequences for human well-being. Direct impacts to human well-being
were grouped into four primary categories, including: (1) toxicological impacts; (2) shifting infectious disease dynamics;
(3) natural hazards; and (4) social health. Social–ecological relationships were altered in complex ways, with both direct
and indirect effects, positive and negative interactions, and chronic and acute impacts on human well-being. Our synthesis
supports a comprehensive evaluation of development projects via integrated assessments of human and environmental consequences.
This is probably best achieved through a coupled social–environmental impact assessment to ensure holistic and comprehensive
analyses of expected costs and benefits. The role of research can thereby be to elucidate the linkages between ecosystems
and human health to better inform the assessment process. A synthesis of the existing information on the Three Gorges suggests
that this is best achieved through institutional collaboration and transdisciplinary integration of expertise. 相似文献
9.
Alzheimer’s disease is an irreversible, progressive neurodegenerative disorder leading invariably to death, usually within
7–10 years after diagnosis and is the leading cause of dementia in the elderly. Not only is Alzheimer’s disease a tragic disease
in which people suffer from neurodegeneration in the years to come, it also becomes an incredible burden on the public health
system. However, there is currently no effective treatment to halt the progression or prevent the onset of Alzheimer’s disease.
This is partly due to the fact that the complex pathophysiology of Alzheimer’s disease is not yet completely understood. Recently,
Golgi apparatus is found to play an important role in Alzheimer’s disease. In this review, we discuss the changes of Golgi
apparatus during clinical progression and pathological development of Alzheimer’s disease. First, changes of Golgi apparatus
size in Alzheimer’s disease are summarized. We then address the role of Golgi apparatus in the neuropathology of Alzheimer’s
disease. Finally, the role of Golgi apparatus in the pathogenesis of Alzheimer’s disease is discussed. Understanding the contribution
of Golgi apparatus dysfunction to Alzheimer’s disease and its pathophysiological basis will significantly impact our ability
to develop more effective therapies for Alzheimer’s disease. 相似文献
10.
Southeast Asia was almost entirely covered by rainforest 8,000 years ago. Today, this region is experiencing the highest relative
rates of deforestation and forest degradation in the humid tropics. Every year, millions of hectares of tropical forests are
destroyed and degraded. Given the rapid rate of deforestation and the high concentration of endemic species in the region,
Southeast Asia could lose 13–42% of local populations by the turn of the next century, at least 50% of which could represent
global species extinction. In this Special Issue, we discuss the uniqueness of Southeast Asian biodiversity, drivers of forest
destruction, threats to the region’s unique ecosystems and taxa, and key conservation challenges to provide a broad-based
review of the science, management and policy issues concerning biodiversity conservation. Overall, we highlight the need for
an interdisciplinary and multi-pronged strategy requiring all major stakeholders to work together to achieve the ultimate
goal of reconciling biodiversity conservation and human well-being in the region. 相似文献
11.
Optimal Investment in Multi-species Protection: Interacting Species and Ecosystem Health 总被引:1,自引:0,他引:1
Stefan Baumgärtner 《EcoHealth》2004,1(1):101-110
This article uses an ecological-economic approach to study optimal investment in multi-species protection when species interact in an ecosystem. The analysis is based on a model of stochastic species extinction in which survival probabilities are interdependent. Individual species protection plans can increase a species survival probability within certain limits and contingent upon the existence or absence of other species. Protection plans are costly and the conservation budget is fixed. It is assumed that human well-being depends solely on the services provided by one particular species, but other species contribute to overall ecosystem functioning and thus influence the first species survival probability. One result is that it may be optimal to invest in the protection of those species that do not directly contribute to human well-being, even if biological conservation decisions are exclusively derived from such a utilitarian framework. Another result is that the rank ordering of spending priorities among different species protection plans, as obtained under the assumption of independent species, may be completely reversed by taking species interaction into account. The conclusion is that effective species protection should go beyond targeting individual species, and consider species relations within whole ecosystems as well as overall ecosystem functioning. Ecosystem health is identified as a necessary prerequisite for successful species protection in situ. 相似文献
12.
Building a 2010 biodiversity conservation data baseline: contributions of the Group on Earth Observations 总被引:1,自引:0,他引:1
Characterizing, modeling, and monitoring the distribution and condition of the Earth’s biodiversity and ecosystems has a long
history of being aided by Earth Observation data and the models and derivative products that they support. At the global scale,
there need to be more coordinated efforts to acquire, process, analyze, and make available these observation data across all
disciplines, particularly since many applications use the same primary and derived data. Towards that end, the Group on Earth
Observations (GEO) is implementing the Global Earth Observing System of Systems. The purpose of this article is to provide
information on GEO’s goals and activities relevant to biodiversity and ecosystems. The article also describes the data that
would best serve as a year 2010 baseline in order to support the objectives of the Convention on Biological Diversity (CBD)
as well as many other international agreements, programs, and activities. Indeed, an assessment of existing biodiversity observations
with a concomitant recognition of the remaining gaps will promote the establishment of an integrated framework for biodiversity
observations in support of the CBD’s efforts. 相似文献
13.
Linking land to ocean: feedbacks in the management of socio-ecological systems in the Great Barrier Reef catchments 总被引:1,自引:1,他引:0
Iain J. Gordon 《Hydrobiologia》2007,591(1):25-33
The Great Barrier Reef (GBR) off Australia’s northeast coast is one of the natural wonders of the world. As a consequence
it has high value, not only for biodiversity, but also for tourists who come to see the GBR and the biodiversity associated
with it, bringing in over A$3.5B per annum to the Australian economy. However, there are a number of natural and anthropogenic
factors that are threatening the health of the reef ecosystems. One of the major anthropogenic factors is the impact of sediments
and nutrients that run off the land, via the rivers, into the lagoon of the reef. Extensive beef production is one of the
major land uses of the GBR catchment, and brings in over $1B to the national economy annually and employs nearly 9,000 people,
many of them in rural communities. Over 70% of terrestrial sediments and nutrients deposited in the GBR lagoon affecting the
health of vulnerable reef ecosystems originate from the extensive grazing lands of Queensland’s interior. Recent research
indicates that the quantity of sediments and nutrients lost from these grazing lands is strongly dependent upon grazing management
practices; grazing leads to degradation of soil and vegetation resources, reduced infiltration and vegetation production.
This has led to a growing concern amongst the Australian public about the environmental performance of the beef industry and
increasing pressures on graziers to change their management practices to decrease the off-farm impacts. Given the constraints
within the system improvements in water quality draining into the GBR lagoon can best be achieved by demonstrating the productivity
and economic benefits of science-based improved grazing management practices for graziers, leading to “AllWin” outcomes for
all concerned. In the longer term, only when the range of stakeholders involved approach catchments as linked biophysical,
social and economic systems, will truly integrated adaptive catchment management be applied to the GBR. 相似文献
14.
Saving camels from straws: how propagule pressure-based prevention policies can reduce the risk of biological invasion 总被引:1,自引:0,他引:1
Nonnative species that harm or have the potential to cause harm to the environment, economy, or human health are known as
invasive species. Propagule pressure may be the most important factor in establishment success of nonnative species of various
taxa in a variety of ecosystems worldwide, and strong evidence is emerging that propagule pressure determines both the scale
of invasion extent and impact. In a limited way, the US government is applying a “propagule pressure approach” in a variety
of prevention policy contexts aimed at minimizing the impact of harmful organisms. However, there are also readily apparent
opportunities for enacting propagule pressure-based measures to fill current gaps in invasive species prevention and control
at national, state, and local levels. An explicit focus on propagule pressure-based policies could substantially increase
the effectiveness of US efforts to prevent the introduction of invasive species through by intentional and unintentional introductions.
The views expressed in this paper are solely those of the authors and do not necessarily reflect those of the US government.
“As the last straw breaks the laden camel’s back...”
-Charles Dickens, Dombey and Son 相似文献
15.
Thomas A. Kursar Catherina C. Caballero-George Todd L. Capson Luis Cubilla-Rios William H. Gerwick Maria V. Heller Alicia Ibañez Roger G. Linington Kerry L. McPhail Eduardo Ortega-Barría Luz I. Romero P. D. Coley 《Biodiversity and Conservation》2007,16(10):2789-2800
The limited international resources for economic aid and conservation can only mitigate poverty and losses of biodiversity.
Hence, developing nations must establish the capacity to resolve their problems. Additionally, policy-makers and donors need
to obtain scientific input on issues such as global change and ecosystem services. We propose that for nations rich in biodiversity,
ecosystem services derived from bioprospecting, or drug discovery, could contribute to economic development. In the case where
unstudied samples are shipped abroad for research, the chances of obtaining royalties are infinitesimally small. Therefore
developing nations will only realize benefits from bioprospecting through in-country research on their own biodiversity. Policy-makers
and donors have failed to appreciate the value of this approach. In order to provide an example of the inherent links between
conservation and sustainable economic development, we initiated a drug discovery effort in Panama that emphasizes local benefit.
As much of the drug discovery process as possible is conducted in Panamanian laboratories, providing jobs dependent on intact
biodiversity and enhancing local research and training. In short, research, plus the spin-offs from research, provide immediate
and long-lasting benefits to Panama. The connection between conservation and development has been highlighted in publicity
about the project in Panama’s urban media. This provides a constructive alternative to the perception the among the urban
populace that economic development inevitably competes with conservation. In summary, our program uses biodiversity to promote
human health as well as to support research capacity, economic development and conservation within Panama. The program provides
an example of the widely recognized but little developed concept of bioprospecting research as an ecosystem service. 相似文献
16.
The views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the USEPA. The U.S. Government has the right to retain a nonexclusive royalty-free license in and to any copyright covering this article. The U.S. Environmental Protection Agency has recognized the need to develop a framework for human health risk assessment that puts a perspective on the approaches in practice throughout the Agency. In response, the USEPA's Risk Assessment Forum has begun the process of developing a framework for human health risk assessment. This paper provides some additional background to the previous review of the framework efforts and notes the Agency's extramural efforts to begin the process of integrating and harmonizing risk assessment approaches for all human health endpoints. 相似文献
17.
Antarctic terrestrial ecosystems currently include very few non-native species, due to the continent’s extreme isolation from
other landmasses. However, the indigenous biota is vulnerable to human-mediated introductions of non-native species. In December
2005, four construction vehicles were imported by contractors to the British Antarctic Survey’s (BAS) Rothera Research Station
(Antarctic Peninsula) from the Falkland Islands and South Georgia (South Atlantic) on board RRS James Clark Ross. The vehicles were contaminated with >132 kg of non-Antarctic soil that contained viable non-native angiosperms, bryophytes,
micro-invertebrates, nematodes, fungi, bacteria, and c. 40,000 seeds and numerous moss propagules. The incident was a significant
contravention of BAS operating procedures, the UK Antarctic Act (1994) and the Protocol on Environmental Protection to the
Antarctic Treaty (1998), which all prohibit the introduction of non-native species to Antarctica without an appropriate permit.
The introduction of this diverse range of species poses a significant threat to local biodiversity should any of the species
become established, particularly as the biota of sub-Antarctic South Georgia is likely to include many species with appropriate
pre-adaptations facilitating the colonisation of more extreme Antarctic environments. Once the incident was discovered, the
imported soil was removed immediately from Antarctica and destroyed. Vehicle cleaning and transportation guidelines have been
revised to enhance the biosecurity of BAS operations, and to minimise the risk of similar incidents occurring. 相似文献
18.
Hatice Şengül 《人类与生态风险评估》2017,23(7):1683-1702
Human Health Area of Protection (HHAoP) has been receiving greater emphasis in recent years in the scope of Environmental Impact Assessment (EIA) of products or services with more impact categories specifically dedicated to include different dimensions of HHAoP. Human health impacts of light sources, however, have received less attention despite their prevalent use for backlighting, general lighting and architectural purposes. Currently, Environmental Product Declarations (EPDs) of lighting devices and electronic devices with backlit screens do not address endpoint impacts nor do they specify technical properties of the light that can enable such an assessment. This study investigates endpoint impacts of eleven lighting devices (1) due to light exposure during the use phase and (2) due to emissions throughout their life cycle. Impacts are quantified as disease burden in terms of disability adjusted life years (DALY). The burden of exposure was calculated using attributable fraction (AF) method. The burden due to life cycle emissions was quantified using GaBi software and built-in life cycle impact assessment (LCIA) method ReCiPe. Endpoint impact categories included were climate change human health, human toxicity, ionizing radiation, ozone depletion, particulate matter formation, and photochemical oxidant formation. The disease burden due to light exposure of all light sources is of two orders of magnitude greater than the disease burden due to life cycle emissions pointing to the need for its treatment. 相似文献
19.
ZHONG-WEI GUO HONG-CHANG LI YA-LING GAN 《Insect Science》2006,13(3):221-227
Interesting results may arise by combining studies on the structure and function of ecosystems with that of biodiversity for certain species. Grasshopper biodiversity is the result of the evolution of grassland ecosystems; however, it also impacts on the structure and the function of those ecosystems. We consider there to be a close relationship between the health of grassland ecosystems and grasshopper biodiversity. The main problems involved in this relationship are likely to include: (i) grasshopper biodiversity and its spatial pattern; (ii) the effect of grasshopper biodiversity on the ecological processes of grassland ecosystems; (iii) the biodiversity threshold of grasshopper population explosions; (iv) the relationship between grasshopper biodiversity and the natural and human factors that affect grassland ecosystems; and (v) grasshopper biodiversity and the health of grassland ecosystems. The solutions to these problems may provide sound bases for controlling disasters caused by grasshoppers and managing grassland ecosystems in the west of China. In this paper, we introduced two concepts for grasshopper biodiversity, that is, "spatial pattern" and "biodiversity threshold". It is helpful to understand the action of the spatial pattern of grasshopper biodiversity on the ecological processes of grassland ecosystems and the effect of this spatial pattern on the health of those ecosystems, owing to the fact that, in the west of China, grasslands are vast and grasshoppers are widely distributed. Moreover, we inferred that the change in the level of component richness at each type of grasshopper biodiversity can make an impact on grassland ecosystems, and therefore, there is likely to be a threshold to grasshopper biodiversity for the stability and the sustainability of those ecosystems. 相似文献
20.
In the analysis of organism life cycles in ecology, comparisons of life cycles between species or between different types
of life cycles within species are frequently conducted. In matrix population models, partitioning of the elasticity matrix
is used to quantify the separate contributions of different life cycles to the population growth rate. Such partition is equivalent
to a decomposition of the life cycle graph of the population. A graph theoretic spanning tree method to carry out the decomposition
was formalized by Wardle [Ecology 79(7), 2539–2549 (1998)]. However there are difficulties in realizing a suitable decomposition for complex life histories using
the spanning-tree method. One of the problems is the occurrence of life cycles that contain contradictory directions that
defy biological interpretation. We propose an algorithmic approach for decomposing a directed, weighted graph. The graph is
to be decomposed into two parts. The first part is a set of simple cycles that contain no contradictory directions and that
consist of edges of equal weight. The second part of the decomposition is a subgraph in which no such simple cycles are obtainable.
When applied to life cycle analysis in ecology, the proposed method will guarantee a complete decomposition of the life cycle
graph into individual life cycles containing no contradictory directions.
Although the research described in this article has been funded in part by the United States Environmental Protection Agency
through STAR cooperative agreement R-82940201-0 to the University of Chicago, it has not been subjected to the Agency’s required
peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should
be inferred. 相似文献