Biodiversity and Saving the Earth

The challenges for reversing course in our stewardship of the earth's ecosystems has never been greater. Biodiversity is in decline on an unprecedented scale and it is tempting to use this as an indicator of the health of the earth's ecosystems. In fact it is one of a number of indicators that collectively provides information on trends in the condition of ecosystems. But the larger problem is the lack of integration between the social and natural sciences. Mainstream scientists continue to reject the notion that solving environmental problems requires an integration of values and processes. A conceptual model shows how these facets may be brought together. A holistic vision requires the integration of natural, social and health sciences. From this perspective the linkage between biodiversity, ecosystem resilience and management options is more clearly articulated.     

Rethinking vulnerability in city-systems: A methodological proposal to assess “urban entropy”

This paper aims at proposing a possible alternative point of view to investigate the vulnerability of urban systems. The basic ideal refers to the possibility of thinking about vulnerability as deriving by the interactions of several risks that can affect the urban system and by the interactions among them. In this sense, it is possible to refer to an “integrated territorial risk”. Considering the city as a complex and dynamic system that while evolving produce entropy is the main theoretical reference supporting this study. The loss of energy during the evolution of the system corresponds to some conditions of inefficiency that involve the whole system and, as such, this lost energy can be assumed as a “systemic entropy”. Is it possible to measure the levels of this vulnerability of the urban system when it stays in ordinary conditions, namely not during stress states that modify the state of equilibrium of the system itself? It is possible to assess the production of this “internal entropy”? In order to answer to these questions in mind, this study aims at analyzing dyscrasias that can occur within the main components of the urban system in order to individuate possible strategies able both to mitigate the fragility of the urban system and to improve its resilience.     

Ecotoxicological Classification of the Berlin River System Using Bioassays in Respect to the European Water Framework Directive

Bioassays as well as biochemical responses (biomarkers) in ecosystems due to environmental stress provide us with signals (environmentally signalling) of potential damage in the environment. If these responses are perceived in this early stage in ecosystems, the eventual damage can be prevented. Once ecosystem damage has occurred, the remedial action processes for recovery could be expensive and pose certain logistical problems. Ideally, “early warning signals” in ecosystems using sensing systems of biochemical responses (biomarkers) would not only tell us the initial levels of damage, but these signals will also provide us with answers by the development of control strategies and precautionary measures in respect to the European Water Framework Directive (WFD). Clear technical guidelines or technical specifications on monitoring are necessary to establish and characterise reference conditions for use in an ecological status classification system for surface water bodies. For the Ecotoxicological Risk Assessment (ERA) of endocrine effects we used an approach of the exposure – dose – response concept. Based on the “Ecototoxicological Classification System of Sediments” that uses pT-values to classify effects in different river systems, we transferred the bio-monitoring data to the five-level ecological system of the WFD. To understand the complexity of the structure of populations and processes behind the health of populations, communities and ecosystems an ERA should establish links between natural factors, chemicals, and biological responses so as to assess causality. So, our ecological monitoring assessment has incorporated exposure & effects data.     

Valuing biodiversity: reality or mirage?

The objective of this paper was to consider the social value ofbiological diversity and explore if this value could be expressedin terms of a unidimensional metric in money. Economics distinguishes between use-values and non-use-values, which are critically evaluated for valuing biodiversity. It is shown that these utility-based valuations have severe limitations as they treat species in isolation from their ecological contexts. In contrast, ecosystem ecology regards ecosystems as an integratednon-linear and nonconvex system in which ecosystem functions canbe understood as a four-component cycle; exploitation, accumulation of biomass, creative destruction and renewal. Withinsuch a cycle, ecosystems can be seen to have two properties: stability and resilience. A good proxy for resilience is the probability of extinction of species, and social value of biodiversity can be expressed as a partial ordering with thisprobability as an index. This approach is consistent with decision theory, of which social choice is an important component, pioneered by Arrow.     

Nitrification,soil acidification and streamwater chemistry following deglaciation,glacier bay national park and preserve

A major tool used in the assessment of anthropic atmospheric effects on aquatic and terrestrial ecosystems is biogeochemical nutrient cycling and budgets. However, to be most effective such study should be done in an ecosystem context. Also some assessment of natural variation in factors affecting nutrient cycling must be in place before trends, often subtle and long-term, attributable to man can be statistically quantified. The input and output balance of chemical species in watershed ecosystems is considerably influenced by ecosystem succession. It is hypothesized that during primary ecosystem succession chemical element output is initially relatively high due to rapid acidification and lack of plant uptake. Outputs decline during the period of high ecosystem productivity and biomass accumulation, and they again rise during late successional stages to approximate inputs from precipitation weathering, and aerosol capture. Glacier Bay provides a unique opportunity to quantify many mechanisms responsible for variation in nutrient cycles without the need for site manipulation. This is especially true for quantifying the rate and magnitude of natural acidification in ecosystems. The park has a spectrum of watersheds differing in stage of primary and secondary succession following deglaciation. These sites are not now subjected to or altered by anthropic atmospheric inputs. The objectives of this research were (1) determine the rate of soil chemical change which occurs following deglaciation, (2) relate soil acidification to presence of organic matter, soil NO _inf3 ^sup- , and total N, (3) estimate the downward movement of ionic species within the soil profiles with increasing acidification from advancing plant succession, and (4) determine if such processes and ionic movements might be reflected in watershed stream ionic outputs. We studied five watersheds ranging from 40–350 years since deglaciation. Soil samples were collected and lysimeters installed in seven vegetation successional stages following deglaciation. An anion of ecological importance and a common air contaminant is NO _inf3 ^sup- , and its discharge in streamflow from early successional ecosystems was found to be high. The terrestrial biota in such systems was dominated by Alnus sinuata, a major nitrogen fixer. Stream discharge of NO _inf3 ^sup- suggested that early successional ecosystem N fixation exceeded biotic uptake. This was confirmed by examining NO _inf3 ^sup- in soil extractions and lysimeters. This process was particularly evident beneath >20-year old Alnus (forty years since deglaciation). concurrent with increased NO _inf3 ^sup- concentrations below the rooting zone was increased H⁺ which increased 100x during 25 years of primary succession. This natural acidification from a mobile NO _inf3 ^sup- ion resulted in an pronounced increase in soil base cation leaching and mobilization of aluminium in the soil profile. The magnitude and short time required for such acidification greatly exceeded anything projected or modeled for systems impacted by anthropic inputs. Stream SO _inf4 ^sup2- concentrations also were high relative to precipitation inputs suggesting mineralization of sulfur within the ecosystem and/or poor soil adsorption of SO _inf4 ^sup2- . This is an important finding in such ecosystems where cation nutrient ion levels are often very low. Should atmospheric inputs of SO _inf4 ^sup2- increase additional loss of cations appears imminent. These data suggest that most early successional ecosystems at Glacier Bay would be sensitive to anthropic inputs of both NO _inf3 ^sup- and SO _inf4 ^sup2- . This is unusual in other ecosystems where many conserve ionic NO _inf3 ^sup- inputs, and older systems have considerable SO _inf4 ^sup2- adsorption capacity. The effect of any increased atmospheric inputs of these ions would be accelerated cation leaching and ecosystem acidification.Contribution from Fourth World Wilderness Congress—Acid Rain Symposium, Denver (Estes Park), Colorado, September 11–18, 1987.     

Vegetation, Soil, and Animal Indicators of Rangeland Health

We studied indicators of rangeland health on benchmark sites with long, well documented records of protection from stress by domestic livestock or histories of environmental stress and vegetation change. We measured ecosystem properties (metrics) that were clearly linked to ecosystem processes. We focused on conservation of soil and water as key processes in healthy ecosystems, and on maintenance of biodiversity and productivity as important functions of healthy ecosystems. Measurements from which indicators of rangeland health were derived included: sizes of unvegetated patches, cover and species composition of perennial grasses, cover and species composition of shrubs and herbaceous perennials, soil slaking, and abundance and species composition of the bird fauna. Indicators that provided an interpretable range of values over the gradient from irreversibly degraded sites to healthy sites included: bare patch index, cover of long-lived grasses, palatability index, and weighted soil surface stability index. Indicators for which values above a threshold may serve as an indicator of rangeland health include: cover of plant species toxic to livestock, cover of exotic species, and cover of increaser species. Several other indicator metrics were judged not sensitive nor interpretable. Examples of application of rangeland health indicators to evaluate the success of various restoration efforts supported the contention that a suite of indicators are required to assess rangeland health. Bird species diversity and ant species diversity were not related to the status of the sample site and were judged inadequate as indicators of maintenance of biodiversity.     

A New Statistical Dynamic Analysis of Ecosystem Patterns

While phenomenological investigations of ecosystem patterns often fail to reveal underlying dynamic mechanisms, we highlight a universal principle for pattern formation in ecosystems. We consider ecosystems to be typical complex adaptive systems that seek an optimal process to obtain maximized flux under given constraints. An analysis of the optimal process reveals underlying microscopic dynamic mechanisms that induce complex patterns in ecosystems. We emulate ecosystem patterns using a Self-Organization Feature Map: an artificial neural network theoretical model by which evolution processes, structural classifications, and the fractal growth of ecosystem patterns can be simulated. The results help us analyze the formation and dynamics of ecosystem patterns, with attending implications for the classification, protection, and optimization of ecosystems.     

Ecosystem classification for EU habitat distribution assessment in sandy coastal environments: An application in central Italy

Many recent developments in coastal science have gone against the demands of European Union legislation. Coastal dune systems which cover small areas of the earth can host a high level of biodiversity. However, human pressure on coastal zones around the world has increased dramatically in the last 50 years. In addition to direct habitat loss, the rapid extinction of many species that are unique to these systems can be attributed to landscape deterioration through the lack of appropriate management. In this paper, we propose to use of an ecosystem classification technique that integrates potential natural vegetation distribution as a reference framework for coastal dune EU Habitats (92/43) distribution analysis and assessment. As an example, the present study analyses the EU Habitats distribution within a hierarchical ecosystem classification of the coastal dune systems of central Italy. In total, 24 land elements belonging to 8 land units, 5 land facets, 2 land systems and 2 land regions were identified for the coastal dunes of central Italy, based on diagnostic land attributes. In central Italy, coastal dune environments including all the beach area, mobile dunes and all the fixed-dune land elements contain or could potentially hold at least one EU habitat of interest. Almost all dune slack transitions present the potentiality for the spontaneous development of EU woodlands of interest. The precise information concerning these ecosystems distribution and ecological relationships that this method produces, makes it very effective in Natura 2000 European network assessment. This hierarchical ecosystem classification method facilitates the identification of areas to be surveyed and eventually bound, under the implementation of EU Habitat directive (92/43) including areas with highly disturbed coastal dune ecosystems.     

Theoretical and practical criteria for the selection of ecosystem monitoring plots in Swiss forests

A great deal of attention has been paid to the selection of nature reserves. These are important from a conservation viewpoint but, for long-term evaluations, it is important to monitor ecosystems. The need for long-term monitoring plots has been recognized for some time in forest ecology. Of the natural ecosystems, forests are some of the most difficult to monitor because of the time-scales involved in the life-spans of the dominant organisms (100 1000 years). The selection of long-term forest ecosystem monitoring plots is a critical process involving decisions that need to remain valid for many years. Traditional sampling theory suggests that some form of systematic or random sampling may be appropriate, but this is usually inappropriate for the selection of ecosystem monitoring plots. Instead, the selection of plots more closely resembles some of the procedures that are used in the selection of nature reserves. In Switzerland, a monitoring programme has been established which uses a number of criteria for the selection of sites. These include site homogeneity, the abundance and sensitivity of the plant communities to change and the presence of pre-existing data series or monitoring equipment. In addition, the human factor is incorporated by selecting sites from throughout the country, with the willingness of the local forest managers to help with the project being an important factor influencing the final choice of plots. In contrast to most inventories, statistical representativeness is not a requirement for the programme, as the plots are treated as a series of case studies.     

Introduction-global to local: Ecological Land Classification

Ecological Land Classification (ELC) is a scientific endeavour which attempts to organize, stratify and evaluate ecosystems (and complexes of ecosystems) for the purposes of land resource management. Since ecosystems themselves are not easily defined in practical terms, ELC is likewise not a trivial concept. Nonetheless, ELC is a prerequisite for ecosystem management and the conservation of biological diversity simply because ecosystems must be described, characterized and spatially-located before they can be managed. Regarding the current status and future direction of ELC, mainly in relation to forest management: 1) approaches to ELC construction and utilization have shifted considerably over the past 2 decades; 2) there appears to be a current consensus regarding basic approaches to ELC; 3) spatial scale is a critical variable that must be addressed by ELCs; 4) ELCs must strive to more directly address management objectives; 5) natural ecosystem functions need to be better integrated within ELC frameworks; and, 6) the need for quality, georeferenced ELC-related data will continue to grow.     

The Biodiversity Crisis and Adaptation to Climate Change: A Case Study from Australia's Forests

If current trends continue, human activities will drastically alter most of the planet's remaining natural ecosystems and their composite biota within a few decades. Compounding the impacts on biodiversity from deleterious management practices is climate variability and change. The Intergovernmental Panel on Climate Change (IPCC) recently concluded that there is ample evidence to suggest climate change is likely to result in significant impacts on biological diversity. These impacts are likely to be exacerbated by the secondary effects of climate change such as changes in the occurrence of wildfire, insect outbreaks and similar disturbances. Current changes in climate are very different from those of the past due to their rate and magnitude, the direct effects of increased atmospheric CO₂ concentrations and because highly modified landscapes and an array of threatening processes limit the ability of terrestrial ecosystems and species to respond to changed conditions. One of the primary human adaptation option for conserving biodiversity is considered to be changes in management. The complex and overarching nature of climate change issues emphasises the need for greatly enhanced cooperation between scientists, policy makers, industry and the community to better understand key interactions and identify options for adaptation. A key challenge is to identify opportunities that facilitate sustainable development by making use of existing technologies and developing policies that enhance the resilience of climate-sensitive sectors. Measures to enhance the resilience of biodiversity must be considered in all of these activities if many ecosystem services essential to humanity are to be sustained. New institutional arrangements appear necessary at the regional and national level to ensure that policy initiatives and research directed at assessing and mitigating the vulnerability of biodiversity to climate change are complementary and undertaken strategically and cost-effectively. Policy implementation at the national level to meet responsibilities arising from the UNFCCC (e.g., the Kyoto Protocol) and the UN Convention on Biological Diversity require greater coordination and integration between economic sectors, since many primary drivers of biodiversity loss and vulnerability are influenced at this level. A case study from the Australian continent is used to illustrate several key issues and discuss a basis for reform, including recommendations for facilitating adaptation to climate variability and change.     

The effect of management systems and ecosystem types on bark regeneration in Himatanthus drasticus (Apocynaceae): recommendations for sustainable harvesting

Bark and exudates are widely commercialized non-timber forest products. However, the ecological impacts of the harvesting of these products have seldom been studied. The aim of this study is to investigate the relationship of tree resilience to harvesting intensity in Himatanthus drasticus, a tree that is highly exploited in the Brazilian savanna (Cerrado) for its medicinal latex. Although the traded product is the latex, the traditional harvesting systems involve the removal of the bark of the trees to allow exploitation. A 3-year experiment was conducted in two different Cerrado ecosystems (open savanna and savanna woodland). Trees were debarked at four debarking intensities to simulate the effects of traditional management systems. Measurements of bark growth were taken every 6 months, and quantitative and qualitative indexes of bark regeneration were obtained. The mortality of the debarked trees was low and could not be related to the intensity of harvesting. No signs of attack by fungi or insects were recorded. Compared with other species exploited for bark, H. drasticus is very resilient to harvesting; however, bark regeneration is relatively slow. In both analyzed ecosystems, the regeneration indexes showed higher values in the controls than in the treatments, indicating that 3 years is not sufficient for total recovery of the rhytidome. Bark regeneration occurred primarily by sheet growth and was more rapid in open savanna than in savanna woodland. No differences in the rate of bark recovery were found among management treatments. Based on the results, sustainable harvesting guidelines are suggested for the species.     

Background monitoring and its role in global estimation and forecast of the state of the biosphere

1. Scientific grounds and the concept of monitoring as the system for observations, assessment and prediction of man-induced changes in the state of natural environment, the program and aims of the background monitoring were developed by the author in 1972–1980. These questions were discussed in detail at the International Symposium on Global Integrated Monitoring (Riga, U.S.S.R., December, 1978). It should be stressed that along with significant anthropogenic loading on large cities and industrial areas, natural ecosystems covering most of the Earth's territory are also exposed to quite extended, though insignificant anthropogenic effects. This paper proposes to consider the ways of the background information use for the biosphere state assessment and prediction.
2. Classification of objects for monitoring from the point of view of the consequences of the man-made impact, pollution in the first hand, is as follows:
3. population (public health);
4. ecosystem elements employed by man whose production is used by population (soil, water bodies, forest, etc.);
5. biotic elements of ecosystems (without the immediate consumed production);
6. abiotic constituents of natural ecosystems, considerable components of the biosphere, climatic system.
7. Historically, monitoring in all countries involves the first two spheres. The background monitoring also extends on the next two spheres. It should differentially take into account physical, chemical and biological factors of impacts. Indentification of biological effects is most complex and vital. Human impact at the background level proceeds indirectly through a general (global or regional) deterioration of the state of the biosphere.
8. Gradually the background monitoring is being practiced on a larger and larger scale. It is shown that the long-range atmospheric transport of pollutants in various regions leads to a gradual general increase of all the natural media pollution and to perceptible biological effects (soil and water acidification and resulting disturbances in the composition of soil and water organisms). The levels of the background impact differ. Thus, the background concentrations of a number of anthropogenic pollutants in Central Europe is 10–20 times higher than in Central Asia.
9. The area of priority in the background monitoring of the biosphere pollution has become evident: compounds of sulphur, mercury and their derivatives, organochloride pesticides, some radioactive substances (e.g., krypton-85 in the atmosphere).
10. The World Ocean is practically all contaminated on a global scale. Biological effects of the World Ocean pollution cause special concern. Particularly important consequences, including climate impact, may be caused by disturbances in energy and matter transfer between environmental media (water-air, water-bottom, etc.). The priority of the impact factors can be allocated here as well: oil products, metals, organochloride compounds, polycyclic aromatic hydrocarbons.
11. One of the most effective possibilities of environmental quality control is standardization which consists in elaboration of permissible ecological loadings upon ecosystems and natural media. The approach to ecological standardization differs from that of hygienic control in principle. The objective of ecological standardization is to ensure the integrity of the given ecosystem and natural environment on the whole.
12. Ecological standardization in its turn requires knowledge related to the damage from this or another impact because in such a case there is a possibility to compare ecological standards for the same ecosystem in the case when impacts are of different origin (e.g., different pollutants).

     

Effects of Temperature–Climate Patterns on the Production of Some Competitive Species on Grounds of Modelling

Climate change has serious effects on the setting up and the operation of natural ecosystems. Small increase in temperature could cause rise in the amount of some species or potential disappearance of others. During our researches, the dispersion of the species and biomass production of a theoretical ecosystem were examined on the effect of the temperature–climate change. The answers of the ecosystems which are given to the climate change could be described by means of global climate modelling and dynamic vegetation models. The examination of the operation of the ecosystems is only possible in huge centres on supercomputers because of the number and the complexity of the calculation. The number of the calculation could be decreased to the level of a PC by considering the temperature and the reproduction during modelling a theoretical ecosystem, and several important theoretical questions could be answered.     

Land use impacts on river health of Uma Oya,Sri Lanka: implications of spatial scales

Human actions on landscapes are a principal threat to the ecological integrity of river ecosystems worldwide. Tropical landscapes have been poorly investigated in terms of the impact of catchment land cover alteration on water quality and biotic indices in comparison to temperate landscapes. Effects of land cover in the catchment at two spatial scales (catchment and site) on stream physical habitat quality, water quality, macroinvertebrate indices and community composition were evaluated for Uma Oya catchment in the upper Mahaweli watershed, Sri Lanka. The relationship between spatial arrangement of land cover in the catchment and water quality, macroinvertebrate indices and community composition was examined using univariate and multivariate approaches. Results indicate that chemical water quality variables such as conductivity and total dissolved solids are mostly governed by the land cover at broader spatial scales such as catchment scale. Shannon diversity index was also affected by catchment scale forest cover. In stream habitat features, nutrients such as N-NO₃ ^?, macroinvertebrate family richness, %shredders and macroinvertebrate community assemblages were predominantly influenced by the extent of land cover at 200 m site scale suggesting that local riparian forest cover is important in structuring macroinvertebrate communities. Thus, this study emphasizes the importance of services provided by forest cover at catchment and site scale in enhancing resilience of stream ecosystems to natural forces and human actions. Findings suggest that land cover disturbance effects on stream ecosystem health could be predicted when appropriate spatial arrangement of land cover is considered and has widespread application in the management of tropical river catchments.     

Monitoring of the functioning of ecosystems

The theoretical basis, the content and the possible applications of the program Monitoring of ecosystems are considered. A functional definition of ecosystem is proposed, and some features of ecosystems are defined on this basis. The program Monitoring of ecosystems is visualized as a large-scale program of simple measurements of the rates of the main ecosystem processes. The expected results can be utilized in two ways: (1) a comparative knowledge of ecosystem functioning provides the fundamentals of geography of ecosystems, and (2) the constant, repeatable evaluation of a given ecosystem function provides a basis for its rational management.     

Using Temporal Coherence to Determine the Response to Climate Change in Boreal Shield Lakes

Climate change is expected to have important impacts on aquatic ecosystems. On the Boreal Shield, mean annual air temperatures are expected to increase 2 to 4°C over the next 50 years. An important challenge is to predict how changes in climate and climate variability will impact natural systems so that sustainable management policies can be implemented. To predict responses to complex ecosystem changes associated with climate change, we used long-term biotic databases to evaluate how important elements of the biota in Boreal Shield lakes have responded to past fluctuations in climate. Our long-term records span a two decade period where there have been unusually cold years and unusually warm years. We used coherence analyses to test for regionally operating controls on climate, water temperature, pH, and plankton richness and abundance in three regions across Ontario: the Experimental Lakes Area, Sudbury, and Dorset. Inter-annual variation in air temperature was similar among regions, but there was a weak relationship among regions for precipitation. While air temperature was closely related to lake surface temperatures in each of the regions, there were weak relationships between lake surface temperature and richness or abundance of the plankton. However, inter-annual changes in lake chemistry (i.e., pH) were correlated with some biotic variables. In some lakes in Sudbury and Dorset, pH was dependent on extreme events. For example, El Nino related droughts resulted in acidification pulses in some lakes that influenced phytoplankton and zooplankton richness. These results suggest that there can be strong heterogeneity in lake ecosystem responses within and across regions.     

Monitoring Ecosystems in the Sierra Nevada: The Conceptual Model Foundation

Monitoring at large geographic scales requires a framework for understanding relationships between components and processes of an ecosystem and the human activities that affect them. We created a conceptual model that is centered on ecosystem processes, considers humans as part of ecosystems, and serves as a framework for selecting attributes for monitoring ecosystems in the Sierra Nevada. The model has three levels: 1) an ecosystem model that identifies five spheres (Atmosphere, Biosphere, Hydrosphere, Lithosphere, Sociocultural), 2) sphere models that identify key ecosystem processes (e.g., photosynthesis), and 3) key process models that identify the "essential elements"that are required for the process to operate (e.g., solar radiation), the human activities ("affectors") that have negative and positive effects on the elements (e.g., air pollution), and the "consequences"of affectors acting on essential elements (e.g., change in primary productivity). We discuss use of the model to select attributes that best reflect the operation and integrity of the ecosystem processes. Model details can be viewed on the web at http://www.r5.fs.fed.us/sncf/spam_report/index.htm(Appendix section).     

The need for long-term stream monitoring programs in forest ecosystems of the Pacific Northwest

Concepts, planning and design procedures are examined that are needed in the development of long-term stream monitoring programs in forested regions. A long-term stream monitoring program is viewed as the key component for bringing together management organizations, researchers and decision-makers to improve the management of natural resources. The keystones of such ecosystem monitoring are long-term data records that provide the basis for analysis of environmental assessment objectives, predictions and analysis of outcomes which in-turn can be used to modify and improve future projects. Management organizations that initiate long-term monitoring programs are urged to use monitoring actions and information to facilitate decision-making processes that pertain to conserving and allocating resources for future beneficial uses. Recommendations are provided for careful planning and definition of interactive activities of monitoring programs and that should provide information feedbacks that can be used to evaluate issues pertaining to beneficial uses of resources. Procedural requirements and literature sources are suggested for developing long-term stream monitoring programs. They include reviews of background and historical information to provide precise definitions of long-term objectives, planning considerations and monitoring methods. Examples are given of specific procedures that need to be identified during the planning process. They include the application of management standards to variable conditions encountered within natural ecosystems and the detection of the timing of recovery phases of stream ecosystem development following a disturbance. These procedures are viewed as being essential for improving applications of management standards and perceived thresholds to stream and watershed ecosystems monitoring programs.     

Design elements of monitoring programs: The necessary ingredients for success

Natural resource managers must know the condition of resources entrusted to their steward-ship so that they can maintain unimpaired resources and know when to restore impaired ecosystems. Resource monitoring programs should be designed to provide indications of ecosystem health, define limits of normal variation, identify abnormal conditions, and suggest potential agents of abnormal changes. Development of a conceptual model that identifies all ecosystem components and their relationships is the first step in the design of such a diagnostic monitoring program. Design studies, with field testing on each selected system component, are required to determine the parameters to be measured and to establish monitoring protocols. The best approach to diagnostic monitoring appears to be based on the population dynamics of selected species relative to physical and chemical environmental factors. Both management and monitoring of natural ecosystems need to be recognized as experimental endeavors, and thus approached in an iterative fashion with the scientific method to reduce uncertainty and cost.