Download or read book The Effects of Drought on Community Structure of Stream Macroinvertebrates written by Kate Roberts and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural stresses such as drought can cause changes in macroinvertebrate community composition over time. This study examines the relationship between low flows, macroinvertebrate habitat and the macroinvertbrate community. The sensitivity of AUSRIVAS biological monitoring methods to impacts associated with low flows are also examined. A flow threshold was used to define low flows and to test for changes in macroinvertebrate habitat and macroinvertebrate communities. Assessments of the biological condition of the macroinvertebrate community were performed using AUSRIVAS predictive models. Low flows reduced the available habitat for macroinvertebrates, thus altering resources for macroinvertebrates. However, macroinvertebrate abundance and community composition showed no significant response to the effects of low. AUSRIVAS assessments detected few reductions in biological condition of macroinvertebrate under low flow conditions. The threshold value used to define drought was useful for determining habitat change, but was appropriate for determinig levels at which changes to the macroinvertebrate community occur. Alternative methods such as a combination of low flow thresholds, low flow duration and channel characteristics may enable observations of biological impacts associated with low flow conditions.
Download or read book Drought and Community Dynamics of Macroinvertebrates in Mediterranean Climate Intermittent Streams of California written by Elena Blair and published by . This book was released on 2017 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although most streams in California are intermittent, bioassessment protocols are designed for perennial streams, with sampling periods anytime between April and June. Sampling intermittent streams during this period may not provide an accurate assessment of stream health, because of the stream community dynamics related to the predictable drying of intermittent streams in Mediterranean climates. Furthermore, climate change may cause perennial streams to become intermittent and intermittent streams to cease flow entirely. The objectives of this study were to assess the recolonization process and community dynamics within and among three intermittent streams each with a different hydrologic regime (dry, isolated pools, and low flow in the summer/fall months) and to assess whether the current bioassessment protocol sampling period appropriately accounts for differences in community composition recovery of intermittent streams. Macroinvertebrates and environmental information were collected at three intermittent streams from August 2013 to July 2014 near Sunol, CA. Sampling was conducted at frequent intervals (1, 8, 15, and 22 days) once stream flow resumed after the dry season; after 22 days, samples were collected every three weeks until the streams dried. All streams exhibited rapid recolonization (especially San Antonio Creek, which only flowed for five weeks) once flow resumed, suggesting taxa were well adapted to the Mediterranean climate and may have resistant/resilient life history traits to survive drying in the summer months. Taxa richness was highest in isolated pool habitats (due to an increase in x predatory and air breathing taxa), contradicting most findings that increased connectivity is associated with higher taxa richness. Non Metric Multidimensional Scaling was used to assess community composition within and among the three streams. Communities became more similar during months of continuous flow (February, March, and early April), suggesting that an earlier sampling window than currently used would be useful for bioassessment. In conclusion, there is a need for more studies regarding macroinvertebrate community dynamics in relation to standard bioassessment sampling protocols and how the effects of floods, flow permanence, and drought influence community dynamics in Mediterranean climate intermittent streams.
Download or read book Stream Hydrology written by Nancy D. Gordon and published by John Wiley & Sons. This book was released on 2013-05-03 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the first edition (1994) there have been rapid developments in the application of hydrology, geomorphology and ecology to stream management. In particular, growth has occurred in the areas of stream rehabilitation and the evaluation of environmental flow needs. The concept of stream health has been adopted as a way of assessing stream resources and setting management goals. Stream Hydrology: An Introduction for Ecologists Second Edition documents recent research and practice in these areas. Chapters provide information on sampling, field techniques, stream analysis, the hydrodynamics of moving water, channel form, sediment transport and commonly used statistical methods such as flow duration and flood frequency analysis. Methods are presented from engineering hydrology, fluvial geomorphology and hydraulics with examples of their biological implications. This book demonstrates how these fields are linked and utilised in modern, scientific river management. * Emphasis on applications, from collecting and analysing field measurements to using data and tools in stream management. * Updated to include new sections on environmental flows, rehabilitation, measuring stream health and stream classification. * Critical reviews of the successes and failures of implementation. * Revised and updated windows-based AQUAPAK software. This book is essential reading for 2nd/3rd year undergraduates and postgraduates of hydrology, stream ecology and fisheries science in Departments of Physical Geography, Biology, Environmental Science, Landscape Ecology, Environmental Engineering and Limnology. It would be valuable reading for professionals working in stream ecology, fisheries science and habitat management, environmental consultants and engineers.
Download or read book Multivariate Analysis of Ecological Data Using CANOCO written by Jan Lepš and published by Cambridge University Press. This book was released on 2003-05-29 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of contents
Download or read book Drought and Aquatic Ecosystems written by P. Sam Lake and published by John Wiley & Sons. This book was released on 2011-06-09 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Droughts are a major hazard to both natural and human-dominated environments and those, especially of long duration and high intensity, can be highly damaging and leave long-lasting effects. This book describes the climatic conditions that give rise to droughts, and their various forms and chief attributes. Past droughts are described including those that had severe impacts on human societies. As a disturbance, droughts can be thought of as “ramps” in that they usually build slowly and take time to become evident. As precipitation is reduced, flows from catchments into aquatic systems decline. As water declines in water bodies, ecological processes are changed and the biota can be drastically reduced, though species and populations may survive by using refuges. Recovery from drought varies in both rates and in degrees of completeness and may be a function of both refuge availability and connectivity. For the first time, this book reviews the available rather scattered literature on the impacts of drought on the flora, fauna and ecological processes of aquatic ecosystems ranging from small ponds to lakes and from streams to estuaries. The effects of drought on the biota of standing waters and flowing waters and of temporary waters and perennial systems are described and compared. In addition, the ways in which human activity can exacerbate droughts are outlined. In many parts of the world especially in the mid latitudes, global warming may result in increases in the duration and intensity of droughts. Drought and Aquatic Ecosystems is essential reading for freshwater ecologists, water resource managers and advanced students.
Download or read book Taking Streams to Extremes written by Thomas William Hallamore Aspin and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is subjecting many ecosystems to novel environmental conditions, including unprecedented extremes of drought that may push communities beyond critical ecological thresholds. Stream ecosystems may be particularly prone to catastrophic responses, due to a dependence on flowing water and continued exposure to other major threats to their ecological integrity. However, a lack of gradient-based approaches that explore beyond the limits of current disturbance regimes constrains our ability to predict the impacts of future droughts. This study used artificial channels (mesocosms) as perennial headwater stream analogues to simulate a broad gradient of drought intensity, ranging from flowing controls through fragmented pools to dewatered streambeds. Drought intensification pushed macroinvertebrate communities over structural and functional thresholds, and eroded complex food webs from the top down and the bottom up. Moreover, important exceptions to some established 'rules' in disturbance ecology emerged, with population collapses not biased to larger body sizes or higher trophic levels, and community responses not buffered by high functional redundancy. Benthic algae, macroinvertebrates and fish were all sensitive to relatively low intensity drought, suggesting that pool fragmentation, and not streambed drying, may be the most crucial stage of habitat loss for many running water ecosystems.
Download or read book Intermittent Rivers and Ephemeral Streams written by Thibault Datry and published by Academic Press. This book was released on 2017-07-11 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intermittent Rivers and Ephemeral Streams: Ecology and Management takes an internationally broad approach, seeking to compare and contrast findings across multiple continents, climates, flow regimes, and land uses to provide a complete and integrated perspective on the ecology of these ecosystems. Coupled with this, users will find a discussion of management approaches applicable in different regions that are illustrated with relevant case studies. In a readable and technically accurate style, the book utilizes logically framed chapters authored by experts in the field, allowing managers and policymakers to readily grasp ecological concepts and their application to specific situations. Provides up-to-date reviews of research findings and management strategies using international examples Explores themes and parallels across diverse sub-disciplines in ecology and water resource management utilizing a multidisciplinary and integrative approach Reveals the relevance of this scientific understanding to managers and policymakers
Download or read book Effects of Land use on the Response of Stream Macroinvertebrate Communities to Drought Fire and Flood Disturbance in the Lower Cotter Catchment written by Anthea R. Florance and published by . This book was released on 2013 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This study examines a long-term data set, collected by the Institute for Applied Ecology (IAE) Freshwater Ecology Laboratory (University of Canberra) between the years of 1994-2013, which takes into account these disturbance events. The objectives of this study were: 1.) to determine how stream macroinvertebrate communities responded to drought, fire and flood disturbance within the LCC [Lower Cotter Catchment] and, 2.) to determine whether former forestry land-use affected how stream macroinvertebrate communities responded to drought, fire and flood disturbance within the LCC."
Download or read book The Waterbug Book written by John Gooderham and published by CSIRO PUBLISHING. This book was released on 2002 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Freshwater invertebrates identification guide for both professionals and non-professionals. Contains a key to all the macroinvertebrate groups and photographs of live specimens.
Download or read book Fluvial Hydrosystems written by G.E. Petts and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluvial Hydrosystems provides a unified approach to the study of running waters and aims to provide a scientific basis for sustainable management of rivers. It differs from traditional texts in viewing rivers as structured, four-dimensional systems and integrating ecological and geomorphological approaches to provide a holistic perspective on river dynamics. Advanced students of geomorphology, ecology, environmental science, land use and civil engineering will all benefit from this wide-ranging and stimulating textbook.
Download or read book Direct and Indirect Effects of Drought on Community Structure and Ecosystem Processes in an Aquatic Ecosystem written by Sarah Louise Amundrud and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Macroinvertebrate Community Composition in Stream Networks Across Three Land Cover Types written by Raj Kiran Parmar and published by . This book was released on 2018 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Land cover change strongly affects biodiversity in stream ecosystems, with several studies demonstrating the negative impacts of agricultural and urban expansion on local community richness. However, little is known of the effects of land cover on the variation among sets of local communities in stream networks, as well as the drivers of community variation in these systems. Using the metacommunity framework, this study takes a multi-scale approach to understand how macroinvertebrate communities are assembled across three catchment land cover types; native forest, agricultural and urban. Specifically, the aims of this study are to assess; (1) how stream network land cover influences alpha and beta diversity of macroinvertebrate communities and, (2) the relative role of local environmental conditions and spatial dispersal variables in structuring these communities. Benthic macroinvertebrate samples and local in-stream and riparian environmental variables were collected at 20 sampling sites in each of the six study stream networks in Auckland. Spatial distance proxies of macroinvertebrate dispersal in stream networks were calculated using geospatial techniques. Community alpha and beta diversity, environmental and distance variables were analysed using multivariate statistical techniques. Comparisons showed reference forest and impacted (agricultural and urban) networks supported distinct communities, with lower alpha diversity in the impacted stream networks. Unexpectedly, beta diversity in the impacted networks was greater than, or equal to the reference stream networks, with community dissimilarity almost entirely driven by species turnover. Overall, irrespective of land cover, macroinvertebrate communities were largely structured by local environmental conditions. Benthic substrate and the presence and composition of riparian vegetation were the most significant local environmental variables influencing community composition. Spatial dispersal limitation variables had a small, but significant, effect on inter-site community dissimilarity and overall community structure in each catchment. Network distance between local communities explained the greatest variation in community dissimilarity of the three distance types. This study identified potential drivers of macroinvertebrate community variation in Auckland streams, specifically highlighting the relative role of local environmental and spatial dispersal processes. The results of this study have relevance for biomonitoring and state of environment reporting of Auckland’s freshwater systems, as well as future stream rehabilitation projects.
Download or read book The Relationships Between Headwater Stream Macroinvertebrate Communities and Summer Low flow Events in a Temperate Rain Forest written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a forested headwater stream system as a model, the effects of inter-annual variation in summer discharge regimes on aquatic insect communities were investigated. More specifically, the benthic invertebrate community response to the intensity, minimum discharges, frequency, duration and abruptness of summer low-flow events were examined. We hypothesized that intensification of summer low-flow events, both in duration and magnitude, have some negative impacts on benthic macroinvertebrate communities in riffles. Examples of negative impacts include reduction in their abundance and/or biodiversity. First, the abundance and functional trait data of the benthic macroinvertebrates in the three streams in the Malcolm Knapp Research Forest, British Columbia, Canada, were analyzed with respect to the low-flow events. Second, population models were built to simulate the potential responses of lotic aquatic insect communities to future climate change scenarios that differ in the rate of intensifications in extreme flow events: a low-flow event scenario within the current range versus 10% increase in intensity. The summer low-flow events were found to have a significant relationship with benthic macroinvertebrate communities through three-table ordinations of the empirical data. The community structure was correlated with a major ocean-atmosphere regime shift (Pacific Decadal Oscillation). The intensity and duration of low-flow events explained the observed shift in community structure favouring r-selected traits (e.g. short life cycle, high reproduction rate). The two low-flow severity scenarios showed the significant differential impacts on the aquatic insect community structures when individual populations were modeled according to their traits. Aquatic insects could be separated into three groups according to their sensitivities, measured by extinction rates, toward the two scenarios.
Download or read book Fire in Mediterranean Ecosystems written by Jon E. Keeley and published by Cambridge University Press. This book was released on 2012 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the role of fire in Mediterranean-type climate ecosystems, providing unique insights into the assembly and evolutionary convergence of ecosystems.
Download or read book An Introduction to the Aquatic Insects of North America written by Richard W. Merritt and published by Kendall Hunt. This book was released on 1996 with total page 894 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Watershed Hydrology written by Vijay P. Singh and published by Allied Publishers. This book was released on 2003 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Limnology in Australia written by P. de Deckker and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: Australia is the world's driest inhabited continent. Water is our limiting resource. It might therefore be thought that our water resources would be the subject of the most intensive study. Certain aspects, it must be conceded, have received much attention, notably the availability of water in terms of actual quantity. The size of the surface water and the groundwater resource is well understood and indeed receives about as much study as can reasonably be expected in a country with as sparse a population and level of scientific manpower as ours. Although the importance of understanding the water resource in terms of quantity is widely accepted, what has not been generally appreciated is that for this resource to be 'available' to human society for all the different uses to which it is put, it is not sufficient that there exists within easy reach of the end users a certain total volume of water. For that water to fulfil its functions-for agriculture, industry, the home, recreation, biological conservation-it must be in a certain state: it must conform to certain chemical, physical and biological criteria, and what has not been sufficiently appreciated in Australian society is that the condition a water is in depends very much on the ecology of the waterbody in which it resides. There are waterbodies in the world, for example high-altitude glacial lakes, which are naturally so pristine that their water could be used for any purpose without treatment.
