Legitimizing Fluvial Ecosystems as Users of Water: An Overview

We suggest that fluvial ecosystems are legitimate users of water and that there are basic ecological principles guiding the maintenance of long-term ecological vitality. This article articulates some fundamental relationships between physical and ecological processes, presents basic principles for maintaining the vitality of fluvial ecosystems, identifies several major scientific challenges and opportunities for effective implementation of the basic ecological principles, and acts as an introduction to three specific articles to follow on biodiversity, biogeochemistry, and riparian communities. All the objectives, by necessity, link climate, land, and fresh water. The basic principles proposed are: (1) the natural flow regime shapes the evolution of aquatic biota and ecological processes, (2) every river has a characteristic flow regime and an associated biotic community, and (3) aquatic ecosystems are topographically unique in occupying the lowest position in the landscape, thereby integrating catchment-scale processes. Scientific challenges for the immediate future relate to quantifying cumulative effects, linking multidisciplinary knowledge and models, and formulating effective monitoring and assessment procedures. Additionally, forecasting the ecological consequences of changing water regimes is a fundamental challenge for science, especially as environmental issues related to fresh waters escalate in the next two to three decades.     

Plains cottonwood's last stand: can it survive invasion of Russian olive onto the Milk River, Montana floodplain?

Russian olive (Elaeagnus angustifolia L.) was introduced in 1950 onto one site on the Milk River floodplain, northern Montana, 10 km downstream from the Canada/United States border. To analyze dispersal of Russian olive from the point source between 1950 and 1999, we compared distribution, numbers, size structure, and mortality of Russian olive and plains cottonwood (Populus deltoides Marsh:) on an unregulated reach of the Milk River floodplain in southeastern Alberta and north-central Montana. Within 50 years, Russian olive in this reach has moved upriver into Alberta and downriver to the Fresno Reservoir. It is now present on 69 of the 74 meander lobes sampled, comprising 34%, 62%, and 61% of all Russian olive and plains cottonwood seedlings, saplings, and trees, respectively. On some meander lobes, Russian olive has colonized similar elevations on the floodplain as plains cottonwood and is oriented in rows paralleling the river channel, suggesting that recruitment may be related to river processes. Breakup ice had killed 400 Russian olive saplings and trees and damaged >1000 others on 30 of the meander lobes in 1996. Nevertheless, Russian olive now outnumbers cottonwood on many sites on the Milk River floodplain because its seeds can be dispersed by wildlife (particularly birds) and probably by flood water and ice rafts; seeds are viable for up to 3 years and germination can take place on bare and well-vegetated soils; and saplings and trees are less palatable to livestock and beaver than plains cottonwood. Without control, Russian olive could be locally dominant on the Milk River floodplain in all age classes within 10 years and replace plains cottonwood within this century.     

Integration of Visual Quality Considerations in Development of Israeli Vegetation Management Policy

This article deals with the visual quality of Mediterranean vegetation groups in northern Israel, the public's preference of these groups as a visual resource, and the policy options for their management. The study is based on a sample of 44 Mediterranean vegetation groups and three population groups of local residents, who were interviewed using a questionnaire and photographs of the vegetation groups. The results of the research showed that plant classification methods based on flora composition, habitat, and external appearance were found to be suitable for visual plant classification and for the evaluation of visual preference of vegetation groups by the interviewed public. The vegetation groups of planted pine forests and olive groves, characterizing a cultured vegetation landscape, were preferred over typical Mediterranean landscapes such as scrub and grassed scrub. The researchers noted a marked difference between the two products of vegetation management policy, one that proposes the conservation and restoration of the variety of native Mediterranean vegetation landscape, and a second that advanced the development of the cultured landscape of planted olive groves and pines forests, which were highly preferred by the public. The authors suggested the development of an integrated vegetation management policy that would combine both needs and thus reduce the gap between the policy proposed by planners and the local population's visual preference.     

Testing the Basic Assumption of the Hydrogeomorphic Approach to AssessingWetland Functions

The hydrogeomorphic (HGM) approach for developing "rapid" wetland function assessment methods stipulates that the variables used are to be scaled based on data collected at sites judged to be the best at performing the wetland functions (reference standard sites). A critical step in the process is to choose the least altered wetlands in a hydrogeomorphic subclass to use as a reference standard against which other wetlands are compared. The basic assumption made in this approach is that wetlands judged to have had the least human impact have the highest level of sustainable performance for all functions. The levels at which functions are performed in these least altered wetlands are assumed to be "characteristic" for the subclass and "sustainable." Results from data collected in wetlands in the lowlands of western Washington suggest that the assumption may not be appropriate for this region. Teams developing methods for assessing wetland functions did not find that the least altered wetlands in a subclass had a range of performance levels that could be identified as "characteristic" or "sustainable." Forty-four wetlands in four hydrogeomorphic subclasses (two depressional subclasses and two riverine subclasses) were rated by teams of experts on the severity of their human alterations and on the level of performance of 15 wetland functions. An ordinal scale of 1-5 was used to quantify alterations in water regime, soils, vegetation, buffers, and contributing basin. Performance of functions was judged on an ordinal scale of 1-7. Relatively unaltered wetlands were judged to perform individual functions at levels that spanned all of the seven possible ratings in all four subclasses. The basic assumption of the HGM approach, that the least altered wetlands represent "characteristic" and "sustainable" levels of functioning that are different from those found in altered wetlands, was not confirmed. Although the intent of the HGM approach is to use level of functioning as a metric to assess the ecological integrity or "health" of the wetland ecosystem, the metric does not seem to work in western Washington for that purpose.     

Managing Urban Trees and Their Soil Envelopes in a Contiguously Developed City Environment

Urban Hong Kong is covered by high building, road, and population densities. Its urban morphology is inherently not conducive to extensive or high-grade greening. Recent renewal of old areas has squeezed out some limited interstitial plantable space, although in new development areas modest spaces have been earmarked for greenery. The study aims at evaluating the major constraints to urban trees and their companion urban soil envelopes and at providing specific recommendations to improve tree management in the city. The analysis covers the above-ground confinements that dampen tree performance, the less tangible but rather difficult institutional restrictions that impose a somewhat unnecessary lid on tree planting, the multiplicity of players and stakeholders involved in urban-tree management that militates against coordination and cooperation, the widespread occupation of underground space by utility lines often to the exclusion of trees, and the extremely poor quality of urban soils that are often used without amelioration to support tree growth. The management recommendations furnish practical suggestions and hints to improve the short- and long-term welfare of trees in terms of quality, quantity, and spatial distribution. The conclusion enumerates some concrete measures for consideration by decision-makers to upgrade the city's greenery to close the gap between science and policy.     

Land-use dynamics in a southern Illinois (USA) watershed

The Cache River of southernmost Illinois is used as a case study for developing and demonstrating an approach to quantitatively link (1) national agricultural policy and global agricultural markets, (2) landowner's decisions on land use, (3) spatial patterns of land use at a watershed scale, and (4) hydrologic impacts, thus providing a basis to predict, under a certain set of circumstances, the environmental consequences of economic and political decisions made at larger spatial scales. The heart of the analysis is an estimation, using logistic regression, of the affect of crop prices and Conservation Reserve Program (CRP) rental rates on farmland owner's decisions whether to reenroll in the CRP or return to crop production. This analysis shows that reasonable ranges for crop prices (80%–150% of 1985–1995 values) and CRP rental rates (0–125% of 1985–1995 rates) result in a range of 3%–92% of CRP lands being returned to crop production, with crop prices having a slightly greater effect than CRP rental rates. Four crop price/CRP rental rate scenarios are used to display resulting land-use patterns, and their effect on sediment loads, a critical environmental quality parameter in this case, using the agricultural non point source (AGNPS) model. These scenarios demonstrate the importance of spatial pattern of land uses on hydrological and ecological processes within watersheds. The approach developed can be adapted for use by local governments and watershed associations whose goals are to improve watershed resources and environmental quality.     

Design and Performance of a Channel Reconstruction Project in a Coastal California Gravel-Bed Stream

A 0.9 km-reach of Uvas Creek, California, was reconstructed as a sinuous, meandering channel in November 1995. In February 1996, this new channel washed out. We reviewed project documents to determine the basis for the project design and conducted our own historical geomorphological study to understand the processes operating in the catchment and project reach. The project was designed using a popular stream classification system, based on which the designers assumed that a "C4" channel (a meandering gravel-bed channel) would be stable at the site. Our historical geomorphological analysis showed that the reach had been braided historically, typical of streams draining the Franciscan Formation in the California Coast Ranges, with episodic flows and high sand and gravel transport. After the project washed out, Uvas Creek reestablished an irregular, braided sand-and-gravel channel, although the channel here was narrower than it had been historically, probably due to such factors as incision caused by gravel mining. Our study casts doubt on several assumptions common in many stream restoration projects: that channel stability is always an appropriate goal; that channel forms are determined by flows with return periods of about 1.5 years; that a channel classification system is an easy, appropriate basis for channel design; and that a new channel form can be imposed without addressing the processes that determine channel form.     

Turning Scientific Approaches into Practical Conservation Actions: The Case of Comunidad Indigena de Nuevo San Juan Parangaricutiro, Mexico

Optimum natural resource management and biodiversity conservation are desirable goals. These, however, often exclude each other, since maximum economic benefits have promoted drastic reductions in biodiversity throughout the world. This dilemma confronts local stakeholders, who usually go for maximizing economic inputs, whereas other social (e.g., academic) sectors are favor conservation practices. In this paper we describe the way two scientific approaches—landscape and participatory research—were used to develop sound and durable land use scenarios. These two approaches included expert knowledge of both social and environmental conditions in indigenous communities. Our major emphasis was given to detect spatially explicit land use scenarios and capacity building in order to construct a decision support system operated by stakeholders of the Comunidad Indigena de Nuevo San Juan Parangaricutiro in Mexico. The system for decision-making was fed with data from inventories of both abiotic and biotic biodiversity components. All research, implementation, and monitoring activities were conducted in close collaboration with members of the indigenous community. As a major result we obtained a number of forest alternative uses that favor emerging markets and make this indigenous community less dependent on a single market. Furthermore, skilled members of the community are now running the automated system for decision-making. In conclusion, our results were better expressed as products with direct benefits in local livelihoods rather than pure academic outputs.     

Environmental Policy Implementation in Rural China: A Case Study of Yuhang, Zhejiang

The rapid growth of rural enterprises has transformed the Chinese countryside. Although rural industrialisation has resulted in increased financial well-being, it has also contributed to decreased environmental quality. While China has strong environmental protection laws, this paper will demonstrate that they are not being effectively implemented in a rural region in Zhejiang Province. This is due to a number of social, political, and economic barriers that prevent agencies from effectively enforcing environmental policies and regulatory mechanisms. This paper investigates the implementation of China's environmental policies through a case study in Yuhang County, Zhejiang Province. It demonstrates that the implementation of environmental impact assessment, discharge fees, and limited time treatment is limited by inadequate technology, low finances, limited human resources, poor public environmental awareness, faulty data, inferior agency reports, organizational conflict, relations based on guanxi, and low discharge fee prices.     

Home Range Size and Choice of Management Strategy for Lynx in Scandinavia

Annual and seasonal home ranges were calculated for 47 Eurasian lynx in four Scandinavian study sites (two in Sweden and two in Norway). The observed home ranges were the largest reported for the species, with study site averages ranging from 600 to 1400 km² for resident males and from 300 to 800 km² for resident females. When home range sizes were compared to the size of protected areas (national parks and nature reserves) in Scandinavia, it was concluded that very few protected areas contained sufficient forest to provide space for more than a few individuals. As a direct consequence of this, most lynx need to be conserved in the multiuse seminatural forest habitats that cover large areas in Scandinavia. This conservation strategy leads to a number of conflicts with some land uses (sheep and semidomestic reindeer herding, and roe deer hunters), but not all (forestry and moose harvest). Accordingly research must be aimed at understanding the ecology of these conflicts, and finding solutions.