Water and Values: Ecological Research as the Basis for Water Management and Nature Management

Over the past 50 years ecology has developed into a mature branch of the natural sciences, comprising firm concepts (e.g. for rivers River Continuum Concept and Flood Pulse Concept) and extensive empirical surveys (sophisticated lab and field experiments, simulation models, GIS). Estuaries and rivers are continuously threatened ecosystems, considering the massive expansion of man’s economic activities. I focus on rivers and estuaries in the Netherlands (W. Europe), where recent public interest has mainly been determined by two flooding disasters (mega-disaster in 1953; near-disaster in 1995). The measures taken to enhance the safety of the human population were adequate: building of large closure dams, and storm surge barriers in the estuaries, and heightening of levees along the rivers. Eventually these measures were detrimental for what was left of the dynamic river ecosystems from the past. This paper focuses on two ecosystem studies. (1) An ecosystem study in Grevelingen lagoon, a large embanked estuary that changed into a brackish water lagoon. Predictive ecological models (e.g. for the wax and wane of Eelgrass, Zostera marina) were inadequate because of the exceptional characteristics of the lagoon: the ecosystem appeared to be instable, and not resilient. (2) An ecosystem study at Afferdensche and Deestsche Waarden, a floodplain area along the river Waal, strongly affected by toxicants deposited before 1980. We studied the functioning and eco-toxicology of floodplain food webs, deteriorated by pollutants. Fine-tuned spatial components were introduced in ecological risk assessment models of several trophic levels (e.g. a top predator, the Little Owl, Athena noctua). Safety for the human population, living below sea level, and below the level of the main rivers, must be improved, but overhasty technocratic measures deteriorating the remaining semi-natural, highly appreciated landscapes, should be avoided. Stakeholder interests must be adapted to sustainable ecological river management, and not the other way round, as has been done for the past ten centuries.     

Linking Water Quality and Quantity in Environmental Flow Assessment in Deteriorated Ecosystems: A Food Web View

Most rivers worldwide are highly regulated by anthropogenic activities through flow regulation and water pollution. Environmental flow regulation is used to reduce the effects of anthropogenic activities on aquatic ecosystems. Formulating flow alteration–ecological response relationships is a key factor in environmental flow assessment. Traditional environmental flow models are characterized by natural relationships between flow regimes and ecosystem factors. However, food webs are often altered from natural states, which disturb environmental flow assessment in such ecosystems. In ecosystems deteriorated by heavy anthropogenic activities, the effects of environmental flow regulation on species are difficult to assess with current modeling approaches. Environmental flow management compels the development of tools that link flow regimes and food webs in an ecosystem. Food web approaches are more suitable for the task because they are more adaptive for disordered multiple species in a food web deteriorated by anthropogenic activities. This paper presents a global method of environmental flow assessment in deteriorated aquatic ecosystems. Linkages between flow regimes and food web dynamics are modeled by incorporating multiple species into an ecosystem to explore ecosystem-based environmental flow management. The approach allows scientists and water resources managers to analyze environmental flows in deteriorated ecosystems in an ecosystem-based way.     

Shoot Resistance to Water Flow in Cotton

Studies using excised cotton (Gossypium hirsutum L.) plants,attached to a free water source and undergoing transpirationcycles, were conducted at intervals over a 2 year period inorder to quantify shoot resistance components of cotton canopies.Leaf water potential was found to be a linear function of transpirationrate at rates above 0.1 mm h^–1, so shoot resistance wasevaluated as the slope of this function. The value of 4.8 104h (0.48 MPa h mm^–1) total shoot resistance was consistentfor 1.10 m tall, well irrigated, fruit-bearing cotton plants.Further tests, with pre-wrapped and exposed leaves, revealedthat total shoot resistance was comprised of an axial component(40%) and a leaf component (60%). The total shoot resistanceof 0.48 MPa h mm^–1 is likely to be relevant for modellingcotton water relations when LWP is evaluated on exposed, topof the canopy leaves, such as in the ‘big leaf’type models. Key words: Leaf water potential, axial resistance, leaf resistance     

Resistance to Water Flow in Xylem Vessels

Experimental data on flow resistances in xylem vessels withdifferent lumen wall surface sculptures are presented. The techniqueinvolved using determinable forces at menisci to pull waterthrough isolated undamaged metaxylem and protoxylem vesselswhich were empty but had water-saturated walls. In the horizontalorientation, the surface tension forces moved the water at velocitiesthat the resisting viscous forces at the vessel walls wouldallow since inertial forces were found negligible. A high speedcamera was used to determine the meniscus translation rates.Vessel diameters as well as average dimensions of the microscopicinternal surface irregularities were measured with respect toaxial position from the inlet. From these, flow resistanceswere determined in terms of dimensionless friction factor, f,as functions of Reynolds number, Re. It was found that, at certain helical ring thicknesses and spacing,resistance to flow was lowest. Deviations from these parametervalues cause dramatic increases in resistance to flow. Resultsare applicable to normal flow in plants, i.e. without meniscipresent.     

Tuberculosis: A Challenge to the General Practitioner

Of 157 patients dying of tuberculosis in Ontario (1960) 132 (87.4%) suffered from the pulmonary form of the disease (incidence 2.6 per 100,000). In the same year, 1632 of 1847, or 88.3%, active new cases reported had the pulmonary type and 183 additional cases were reported without details as to type of disease. Thus, in 1960, a total of 2030 new cases of tuberculosis were reported in Ontario.Of 1367 patients with pulmonary tuberculosis (reinfection type), 357 (26.1%) had “far advanced” disease and 613 (44.8%) had “moderately advanced” disease.This high percentage of patients with “moderately advanced” to “far advanced” disease at the time of diagnosis constitutes the real challenge to physicians in private practice, who made the diagnosis in 45% of cases.Emergence of resistant strains of bacteria increases the urgency of prompt diagnosis and treatment. The most vulnerable population segment is the 15-30 year age-group, many of whom are negative intracutaneous reactors. A high index of suspicion is necessary, particularly in certain segments of the population with a high incidence of infection, combined with a careful history, meticulous physical examination, intracutaneous tests, chest and other radiographs, and appropriate bacteriological studies.     

Urban Stormwater Runoff: A New Class of Environmental Flow Problem

Environmental flow assessment frameworks have begun to consider changes to flow regimes resulting from land-use change. Urban stormwater runoff, which degrades streams through altered volume, pattern and quality of flow, presents a problem that challenges dominant approaches to stormwater and water resource management, and to environmental flow assessment. We used evidence of ecological response to different stormwater drainage systems to develop methods for input to environmental flow assessment. We identified the nature of hydrologic change resulting from conventional urban stormwater runoff, and the mechanisms by which such hydrologic change is prevented in streams where ecological condition has been protected. We also quantified the increase in total volume resulting from urban stormwater runoff, by comparing annual streamflow volumes from undeveloped catchments with the volumes that would run off impervious surfaces under the same rainfall regimes. In catchments with as little as 5–10% total imperviousness, conventional stormwater drainage, associated with poor in-stream ecological condition, reduces contributions to baseflows and increases the frequency and magnitude of storm flows, but in similarly impervious catchments in which streams retain good ecological condition, informal drainage to forested hillslopes, without a direct piped discharge to the stream, results in little such hydrologic change. In urbanized catchments, dispersed urban stormwater retention measures can potentially protect urban stream ecosystems by mimicking the hydrologic effects of informal drainage, if sufficient water is harvested and kept out of the stream, and if discharged water is treated to a suitable quality. Urban stormwater is a new class of environmental flow problem: one that requires reduction of a large excess volume of water to maintain riverine ecological integrity. It is the best type of problem, because solving it provides an opportunity to solve other problems such as the provision of water for human use.     

Forecasting Environmental Responses to Restoration of Rivers Used as Log Floatways: An Interdisciplinary Challenge

Log floating in the 19th to mid 20th centuries has profoundly changed the environmental conditions in many northern river systems of the world. Regulation of flow by dams, straightening and narrowing of channels by various piers and wing dams, and homogenization of bed structure are some of the major impacts. As a result, the conditions for many riverine organisms have been altered. Removing physical constructions and returning boulders to the channels can potentially restore conditions for these organisms. Here we describe the history of log driving, review its impact on physical and biological conditions and processes, and predict the responses to restoration. Reviewing the literature on comparable restoration efforts and building upon this knowledge, using boreal Swedish rivers as an example, we address the last point. We hypothesize that restoration measures will make rivers wider and more sinuous, and provide rougher bottoms, thus improving land-water interactions and increasing the retention capacity of water, sediment, organic matter and nutrients. The geomorphic and hydraulic/hydrologic alterations are supposed to favor production, diversity, migration and reproduction of riparian and aquatic organisms. The response rates are likely to vary according to the types of processes and organisms. Some habitat components, such as beds of very large boulders and bedrock outcrops, and availability of sediment and large woody debris are believed to be extremely difficult to restore. Monitoring and evaluation at several scales are needed to test our predictions.     

Ecosystem Approach to Rapid Health Assessments among Indigenous Cultures in Degraded Tropical Rainforest Environments: Case Study of Unexplained Deaths among the Secoya of Ecuador

Large-scale economically-driven encroachments into tropical rainforest environments are major factors for disease emergence. A better understanding of the process of disease emergence can be best derived from a multilevel, transdisciplinary ecosystem approach that analyzes health data in its biological, ecological, social, and cultural context. Multiple methods, including ethnographic techniques, are recommended for such an approach. The value of this approach and methodology is presented in this article through a rapid health assessment case study of an unexplained fatal syndrome that occurred among the Secoya peoples of the Ecuadorian Amazon in 1999. This type of study is significant given the lack of health data for indigenous populations at risk of disease emergence. Moreover, indigenous cultures share a long-term, close relationship to the land and each other, which makes information about changes in their environment and health patterns highly salient to them. This local knowledge is of strategic value to researchers working on issues of environmental change and disease emergence.     

Non-coding RNAs in Crop Genetic Modification: Considerations and Predictable Environmental Risk Assessments (ERA)

Of late non-coding RNAs (ncRNAs)-mediated gene silencing is an influential tool deliberately deployed to negatively regulate the expression of targeted genes. In addition to the widely employed small interfering RNA (siRNA)-mediated gene silencing approach, other variants like artificial miRNA (amiRNA), miRNA mimics, and artificial transacting siRNAs (tasiRNAs) are being explored and successfully deployed in developing non-coding RNA-based genetically modified plants. The ncRNA-based gene manipulations are typified with mobile nature of silencing signals, interference from viral genome-derived suppressor proteins, and an obligation for meticulous computational analysis to prevaricate any inadvertent effects. In a broad sense, risk assessment inquiries for genetically modified plants based on the expression of ncRNAs are competently addressed by the environmental risk assessment (ERA) models, currently in vogue, designed for the first generation transgenic plants which are based on the expression of heterologous proteins. Nevertheless, transgenic plants functioning on the foundation of ncRNAs warrant due attention with respect to their unique attributes like off-target or non-target gene silencing effects, small RNAs (sRNAs) persistence, food and feed safety assessments, problems in detection and tracking of sRNAs in food, impact of ncRNAs in plant protection measures, effect of mutations etc. The role of recent developments in sequencing techniques like next generation sequencing (NGS) and the ERA paradigm of the different countries in vogue are also discussed in the context of ncRNA-based gene manipulations.     

The Challenge of Planning Conservation Strategies in Threatened Seascapes: Understanding the Role of Fine Scale Assessments of Community Response to Cumulative Human Pressures

Assessing the distribution and intensity of human threats to biodiversity is a prerequisite for effective spatial planning, harmonizing conservation purposes with sustainable development. In the Mediterranean Sea, the management of Marine Protected Areas (MPAs) is rarely based on explicit consideration of the distribution of multiple stressors, with direct assessment of their effects on ecosystems. This gap limits the effectiveness of protection and is conducive to conflicts among stakeholders. Here, a fine scale assessment of the potential effects of different combinations of stressors (both land- and marine-based) on vulnerable rocky habitats (i.e. lower midlittoral and shallow infralittoral) along 40 km of coast in the western Mediterranean (Ionian Sea) has been carried out. The study area is a paradigmatic example of socio-ecological interactions, where several human uses and conservation measures collide. Significant differences in the structure of assemblages according to different combinations of threats were observed, indicating distinct responses of marine habitats to different sets of human pressures. A more complex three-dimensional structure, higher taxon richness and β-diversity characterized assemblages subject to low versus high levels of human pressure, consistently across habitats. In addition, the main drivers of change were: closeness to the harbour, water quality, and the relative extension of beaches. Our findings suggest that, although efforts to assess cumulative impacts at large scale may help in individuating priority areas for conservation purposes, the fact that such evaluations are often based on expert opinions and not on actual studies limits their ability to represent real environmental conditions at local scale. Systematic evaluations of local scale effects of anthropogenic drivers of change on biological communities should complement broad scale management strategies to achieve effective sustainability of human exploitation of marine resources.     

Aerobic Heterotrophic Bacteria Indigenous to pH 2.8 Acid Mine Water: Microscopic Examination of Acid Streamers

"Acid streamers" found in acid coal mine drainage consist of bacteria trapped within an extracellular fibrillar polymer network. Inorganic compounds also precipitate within the polymer network. Several bacteria which appear to be different and are presumed to be different species are associated in the slimy mass of the "acid streamers." The "streamers" contain individual microcolonies or microcosms that can be recognized by a selective polysaccharide stain, which suggests that the slime streamer is a conglomeration of polymers produced by more than one species.     

Indigenous and expatriate addicts in Laos: A Comparison

Opium addiction has been reported among virtually all large ethnic groups in Asia. Conspicuous by its absence has been any mention of addiction among the Lao, a people surrounded by poppy-growing tribal groups. A sample of Lao patient-addicts are here compared to expatriate Asian addicts in Laos.Lao and expatriate addicts show marked similarity in their sociodemographic profiles and patterns of narcotic use. Some differences in their recent use of narcotic drugs appear related to the greater cash income of the expatriate Asians and their greater access to heroin. No specifically cultural factors for explaining ethnic differences in addiction have yet been identified.Acknowledgement is expressed to Dr. Charles Weldon, Dr. Chomchan Soudaly, Mr. Larry Berger, and Mr. Boun Ke for their support and assistance in this study. Ms. Grace Peng and Ms. Beth Stone assisted in the tabulation and analysis of the data. The project was supported by the Minnesota Medical Foundation, the International Programs Office at the University of Minnesota, and the National Institute of Drug Abuse (grant no. 5 T01 DA 00023-02 and grant no. 1 R01 DA 01599-01).     

Environmental Change and Pastoral Perceptions: Degradation and Indigenous Knowledge in Two African Pastoral Communities

Mobile livestock herders have long been seen as the main culprits of over-stocking and rangeland degradation. In recent years, however, anthropologists and ecologists have argued that African pastoralists have developed sustainable modes of pasture management based on a sound knowledge of savanna ecosystems. Comparing indigenous knowledge on species' grazing values, plant succession, and ideas about the causes for environmental change in two African pastoral societies (the Kenyan Pokot and the Namibian Himba), it is shown that their knowledge is indeed fine-grained and complex but at the same time socially constructed and embedded in ideology. It relates to a cultural landscape and not to abstract considerations on climax vegetation and its changes over time. Pastoral knowledge is built up around the interaction between herds and vegetation rather than around the environment as such.