Monitoring and assessment of macroinvertebrate communities in support of river management in northern Vietnam

The thesis aimed to develop a water quality biological monitoring and assessment based on macro-invertebrates to analyse the status of watercourses and to select sustainable restoration measures in order to support river. The research was carried in the Du river basin in northern Vietnam. Spatial and temporal analysis showed that macro-invertebrate community compositions in the Du river were not only driven by morphological characteristics but also by water quality issues. A relatively small temporal variation was detected that requires no remarkable modifications in the development of a bio-assessment methodology for watercourses in the specific river. Multivariate analyses using CCA and Bray-Curtis cluster analysis provided a similar discrimination between pristine and impacted sites in the Du river basin. Qualitative biotic indices including the BMWP-Viet proved to be appropriate for use in the studied watercourses in Vietnam. The BMWP-Viet could differentiate study sites into classes ranging from very good to very poor ecological conditions. The current BMWP-Viet approach can be useful at an early stage of bio-assessment application in Vietnam. However, this method should be improved by optimising the scoring system for common taxa and development of more robust assessment approaches such as multi-metric indices. Data mining techniques including classification trees and support vector machines were applied to develop predictive models for BMWP-Viet as well as presence/absence of macro-invertebrate taxa (ecological indicators). Optimised models indicate the major environmental variables influencing the presence/absence of macro-invertebrates, which in the mean time also reflect the river characteristics that river managers have to consider in their policy plans. A decision support system, the WFD-Explorer was combined with classification trees to link human activities with the ecological river conditions and analyse the relevance of several restoration options

Spatial and environmental patterns of rare lotic macroinvertebrate diversity : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Manawatū, Palmerston North, New Zealand

Stream macroinvertebrate communities comprise a few common taxa and many rare ones. Small populations of rare taxa can be more vulnerable to environmental change than those of common taxa. However, they are often discarded from community analyses on the grounds that they complicate data interpretation. The aim of this thesis was to evaluate the effect of rare taxa on assessing ecosystem health and on interpreting biodiversity patterns based on lotic macroinvertebrate communities. I assessed the effect of multiple types of rare taxa exclusion on biomonitoring, using macroinvertebrate data collected for the National River Water Quality Network of Aotearoa New Zealand. I compared the effect of different sampling methods on biodiversity patterns of rare taxa in pristine streams in the Tongariro National Park and determined the local environmental variables most strongly linked with common and rare taxa. Finally, I evaluated the effect dispersal processes and local environment have on structuring the common and rare components of lotic communities, considering the position within the stream network and the dispersal mode of the invertebrates. Exclusion of rare taxa led to significant misclassifications of ecological quality by biomonitoring tools that use presence-absence data, such as the Macroinvertebrate Community Index, and often masked their relationship with nutrient stressors. Different sampling methods collected clearly differentiated rare components of lotic assemblages, depending on the habitat sampled (riffles, non-riffles) and the life-stage of the invertebrates (benthic larvae, flying adults). A comprehensive species inventory can be compiled by combining methods, with benthic samples as the basis. Biodiversity metrics of the common and rare components of macroinvertebrate communities were related to similar environmental variables. While the structure of the two components was related to different variables, in combination they revealed a greater number of relationships with the environment. Rare taxa assemblages were not structured clearly by either local environment or dispersal processes, however their inclusion was necessary to demonstrate that the complete communities were determined by the local environment. Overall, I did not find any reason to exclude rare taxa from lotic macroinvertebrate studies, but rather found they can facilitate community analyses. Given the increasing threats on lotic macroinvertebrate biodiversity, it is also crucial to include them in such studies, hopefully so we can prevent their complete extinction

Model-based analysis of the potential of macroinvertebrates as indicators for microbial pathogens in rivers

The quality of water prior to its use for drinking, farming or recreational purposes must comply with several physicochemical and microbiological standards to safeguard society and the environment. In order to satisfy these standards, expensive analyses and highly trained personnel in laboratories are required. Whereas macroinvertebrates have been used as ecological indicators to review the health of aquatic ecosystems. In this research, the relationship between microbial pathogens and macrobenthic invertebrate taxa was examined in the Machangara River located in the southern Andes of Ecuador, in which 33 sites, according to their land use, were chosen to collect physicochemical, microbiological and biological parameters. Decision tree models (DTMs) were used to generate rules that link the presence and abundance of some benthic families to microbial pathogen standards. The aforementioned DTMs provide an indirect, approximate, and quick way of checking the fulfillment of Ecuadorian regulations for water use related to microbial pathogens. The models built and optimized with the WEKA package, were evaluated based on both statistical and ecological criteria to make them as clear and simple as possible. As a result, two different and reliable models were obtained, which could be used as proxy indicators in a preliminary assessment of pollution of microbial pathogens in rivers. The DTMs can be easily applied by staff with minimal training in the identification of the sensitive taxa selected by the models. The presence of selected macroinvertebrate taxa in conjunction with the decision trees can be used as a screening tool to evaluate sites that require additional follow up analyses to confirm whether microbial water quality standards are met

Freshwater Macroinvertebrates: Main Gaps and Future Trends

Freshwater macroinvertebrates play a crucial role in linking sediments and their processes to the food web. Indeed, environmental modifications (e.g., nitrogen deposition, salinity, and temperature increase), pollution (e.g., pesticides and heavy metals), and introduction of alien species are the main drivers of changes that are affecting their communities. This Special Issue aims to present the past and present knowledge on freshwater macroinvertebrates to understand their role as providers of ecosystem services, to highlight the effects of global changes on their community (in the short and long term), and to underline major gaps in their study. Finally, in order to tackle the currently unsustainable use of freshwater natural capital, we welcome ideas and expert opinions on the development of future research linked to national and international regulations

A continental landscape framework for systematic conservation planning for Australian rivers and streams

Conservation of Australia’s distinctive river ecosystems has lagged behind that of terrestrial and marine environments despite mounting evidence of the destructive effects of human activities. There has been little nationally coordinated conservation activity. A systematic, continent-wide conservation planning approach would ensure limited conservation resources are allocated efficiently and decisions are accountable. This thesis addresses critical gaps in the spatial data required for systematic conservation planning. It describes the development of a stream network and nested catchment reference system to provide the spatial framework. This framework, at a map scale of approximately 1:250,000, supplies planning units for application of reserve design algorithms and determination of priorities for protective management as well as units for reporting conservation evaluation and assessment. The Pfafstetter coding of the catchment units identifies drainage network connectivities allowing them to be readily incorporated into conservation planning procedures. This thesis presents for the first time a comprehensive picture of continent-wide variation in the landscape factors that ultimately control riverine ecosystem patterns and processes. Stream segments, the section of the stream between tributary confluences and the smallest unit in the spatial framework, have been individually characterized and classified at multiple scales using attributes that describe the catchment (and/or sub-catchment) climate, water balance, geology, terrain and vegetation. Segments were clustered according to their similarity in environmental data space so that, unlike ecoregion classifications, groups may be geographically dispersed. The resulting River Environment Types have been found to differentiate significant variation in stream biota (macroinvertebrates and fish) and habitat characteristics. However, classification strength varies widely among types. It is hypothesised that this is due to both classification uncertainty and limitations of the test data. The spatial framework and classifications are the central elements of a continental landscape framework that could be used to support systematic conservation planning and assist the development of a national conservation plan for Australia’s rivers and streams. The framework could also provide the basis for an online information system to serve a broader range of NRM planning and management objectives. The utility of the continental framework has been demonstrated in a review of the National Reserve System (NRS). The review acknowledges some uncertainty in the results due to inaccuracies and limitations of the framework, but nevertheless, concludes that the NRS must be expanded if it is to achieve a comprehensive and adequate protected area system for river ecosystems. This study makes major contributions to spatial analysis methodology. It has developed and applied a new method of drainage analysis applicable to diverse drainage structures at continental scale and recommends enhancements to the internationally adopted Pfafstetter scheme. It also advances understanding of the role for landscape classification and the influence of classification choice on conservation planning outcomes. The development of the continental landscape framework for Australia presents a model and the necessary tools for conservation planning for the rivers and streams of other continents

Inland Waters

Inland waters, lakes, rivers, and their connected wetlands are the most important and the most vulnerable sources of freshwater on the planet. The ecology of these systems includes biology as well as human populations and civilization. Inland waters and wetlands are highly susceptible to chemical and biological pollutants from natural or human sources, changes in watershed dynamics due to the establishment of dams and reservoirs, and land use changes from agriculture and industry. This book provides a comprehensive review of issues involving inland waters and discusses many worldwide inland water systems. The main topics of this text are water quality investigation, analyses of the ecology of inland water systems, remote sensing observation and numerical modeling methods, and biodiversity investigations