Management Of Aquatic Habitats Research Articles

Telemetry-based spatial–temporal fish habitat models for fishes in an urban freshwater harbour

Fish habitat associations are important measures for effective aquatic habitat management, but often vary over broad spatial and temporal scales, and are therefore challenging to measure comprehensively. We used a 9-year acoustic telemetry dataset to generate spatial–temporal habitat suitability models for seven fish species in an urban freshwater harbour, Toronto Harbour, Lake Ontario. Fishes generally occupied the more natural regions of Toronto Harbour most frequently. However, each species exhibited unique habitat associations and spatial–temporal interactions in their habitat use. For example, largemouth bass exhibited the most consistent seasonal habitat use, mainly associating with shallow, sheltered embayments with high aquatic vegetation (SAV) cover. Conversely, walleye seldom occupied Toronto Harbour in summer, with the highest occupancy of shallow, low-SAV habitats in the spring, which corresponds to their spawning period. Others, such as common carp, shifted between shallow summer and deeper winter habitats. Community level spatial–temporal habitat importance estimates were also generated, which can serve as an aggregate measure for habitat management. Acoustic telemetry provides novel opportunities to generate robust spatial–temporal fish habitat models based on wild fish behaviour, which are useful for the management of fish habitat from a fish species and community perspective.

Recurrent debris flows and their downstream fate: Geomorphic drivers of an anomalous sediment load, Suiattle River, Washington State, USA

AbstractAlpine mass wasting events have impacts that extend past their headwater origins, sometimes reaching populated lowlands. Understanding the processes driving these sediment pulses, and how they contribute to basin‐scale sediment fluxes, is important for hazard assessment and aquatic habitat management. The Suiattle River, which drains Glacier Peak stratovolcano in Washington State, is a dominant contributor of suspended sediment in the region. Normalized for drainage area, it supplies more suspended sediment than nearly any other river in the area and more than twice as much as the White Chuck River, which drains the opposite flank of the volcano. Despite its importance to the regional sediment budget, geomorphic processes in the basin have received relatively little attention in the literature. In this study, we build on previous work to explore the magnitude, timing and triggering mechanisms of sediment loading events in the basin. We find that outburst flood‐triggered debris flows from Chocolate Glacier are of widely varying magnitude and coincide with high temperatures in the late summer. Major debris flow activity initiated in the late 1930s, with at least eight valley‐filling debris flows since then. Smaller, more recent debris flows, likely also driven by outburst floods, occur in five of seven years of complete data. In total, the small debris flows and the subsequent autumn flushing events explain ~21% of the ‘anomalous’ sediment load in the basin, while reworking and abrasion of the historic events may explain another ~26%. We speculate that some of the remaining unexplained ‘anomalous’ load could be the result of a feedback between channel lateral instability (originally triggered by the valley‐spanning debris flows) and bluff erosion.

Evolution of Native and Alien Macrophytes in a Fluvial‐wetland System Using Long‐term Satellite Data

An overgrowth of invasive floating macrophytes can occur in shallow eutrophic lakes as a result of significant anthropogenic pressures. This necessitates appropriate monitoring, followed by informed management, control and mitigation actions. In this study, we explored the long-term dynamics of macrophyte stands in a fluvial-wetland system and the influence of mechanical removal alongside environmental drivers. The Landsat imagery archive was used to analyze the areal coverage and canopy density of both autochthonous and allochthonous macrophytes in the Mantua lakes system (Northern Italy). Satellite derived data showed a substantial increase in the extent of the alien Nelumbo nucifera, and Ludwigia hexapetala, and the native Trapa natans over a timescale of decades, possibly caused by the temporary absence of macrophyte removal and altered hydrology. According to spectral proxies, N. nucifera recorded consistently the highest density in the system. T. natans density was found to respond to the maximum summer temperature and Eastern Atlantic climatic index, reflecting the role of regional climatic controls. This approach may be transferred to inland waters from regional to global scale exploiting satellite archives to obtain a time series on changing species dynamics essential for the conservation and management of aquatic habitats.

Classifying connectivity to guide aquatic habitat management in an arctic coastal plain watershed experiencing land use and climate change

ABSTRACT Habitat connectivity supports life history requirements of many arctic fish species during periods of flowing water. However, aquatic habitat connectivity is susceptible to change due to climate factors and land use, particularly in the 4,600 km2 Fish Creek Watershed (FCW) located in National Petroleum Reserve in Alaska. Varying degrees and mechanisms of connectivity between overwintering habitat and summer foraging habitat motivated us to assess and classify aquatic habitat connectivity to help inform management. Using geospatial analysis and field methods we classified processes affecting connectivity within riparian corridors and upstream channels. Results show the dominant geomorphic process affecting connectivity varied among river systems, providing general and catchment-specific guidance as to the distribution of important migratory fish habitat. Barriers to fish passage caused by subsurface flow were more common along river corridors with high channel migration rates, whereas wetland flowthrough was the most common barrier in upstream catchments throughout the FCW. Coupling both riparian and catchment connectivity showed that 28 percent of catchments were classified as having fish-passable connectivity, indicated by no barriers present in the riparian zone or upstream channels. Future work should evaluate how well this classification predicts fish habitat, is useful to resource management, and is applicable to other arctic watersheds.

Evaluating the Effects of Barriers on Slimy Sculpin Movement and Population Connectivity Using Novel Sibship‐based and Traditional Genetic Metrics

AbstractPopulation genetics‐based approaches can provide robust and cost‐effective ways to assess the effects of potential barriers, including dams and road‐stream crossings, on the passage and population connectivity of aquatic organisms. Determining the best way to apply and modify genetic tools for different species and situations is essential for making these genetics‐based approaches broadly applicable to fisheries and aquatic habitat management. Here, we used multiple genetic approaches to assess the movement and population structure of Slimy Sculpin Cottus cognatus at two road‐stream crossings in Michigan and one dam in Massachusetts, USA. We captured and genotyped individual sculpin and assessed movement and population connectivity by using (1) a sibship‐based approach, where the presence and proportional distribution of siblings on either side of a barrier indicates population connectivity and the possible direction of movement (i.e., presumed movement from higher to lower proportions), and (2) two Bayesian genetic assignment approaches (STRUCTURE and BayesAss) to identify migrants across potential barriers based on individual population assignment probabilities. We also used traditional genetic metrics to assess within‐population genetic variation and among‐population genetic divergence. At all three locations, we found evidence for sculpin movement across the potential barrier based on sibship reconstruction, but small family sizes limited the ability of this approach to provide robust estimates of the rate and direction of movement. At two sites, a lack of genetic differentiation between above‐ and below‐barrier populations limited the effectiveness of the genetic assignment methods for identifying possible migrants. At the third site, reduced upstream allelic diversity and effective number of breeders resulted in high genetic differentiation (FST) between above‐ and below‐barrier populations, and both sibship and genetic assignment methods provided strong evidence of limited connectivity and bias against upstream movement. Overall, combining approaches and metrics may help overcome the limitations of any one method and maximize the value of datasets for genetics‐based monitoring and assessment.

Inland Fisheries Habitat Management: Lessons Learned from Wildlife Ecology and a Proposal for Change

The habitat concept in inland fisheries has been less studied than wildlife ecology. Since 1950, the cumulative number of publications about “freshwater or inland habitat and fisheries management” has been 60%–95% less than those considering “habitat and wildlife management.” The number of publications about “marine, river, and stream habitat and fisheries management” has also generally exceeded those for “lake habitat and fisheries management.” We provide a perspective comparing inland fish and wildlife habitat management systems and highlight lessons from wildlife ecology that could benefit inland fisheries. We reason that wildlife habitat management has become widespread and accepted because humans share habitats with wildlife and positive/negative responses to habitat restorations/loss are directly observable. We recommend that inland fisheries habitat studies and restorations include opportunities for humans to directly observe the ecological benefits of such practices. To support aquatic habitat management efforts, we suggest that dedicated funding solutions be considered to mitigate aquatic habitat loss. In theory, such a system would provide benefits to inland fish populations that parallel those provided to wildlife through state and federal stamps. Although aquatic habitat conservation and restoration may not solve management issues as rapidly, it will promote long‐term sustainability and resiliency of diverse inland fish populations.

Environmental thresholds and predictors of macrophyte species richness in aquatic habitats in central Europe

The degradation of habitats and species loss in freshwaters is far greater than in any other ecosystem. The decline in biodiversity has a strong potential to alter the functioning of the ecosystem and the services they provide to human society. Therefore, there is an urgent need for accurate information on patterns and drivers of diversity that could be used in the management of freshwater ecosystems. We present the results of an analysis of the relationships between macrophyte species richness and environmental characteristics using an extensive dataset collected from 160 sites in two central-European bioregions. We modelled macrophyte species richness using recursive partitioning methods to assess the diversity-environmental relationships and to estimate the environmental thresholds of species richness in rivers, streams, ditches and ponds. Several hydrological and chemical variables were identified as significant predictors of macrophyte richness. Among them, pH, conductivity, turbidity and substrate composition appeared as the most important. There is also evidence that natural ponds support a greater number of plant species than man-made ponds. Based on the detected environmental thresholds, we offer a series of simple rules for maintaining higher macrophyte species richness, which is potentially useful in the conservation and management of aquatic habitats in central Europe.

New distributional data on aquatic and semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha & Nepomorpha) from South America.

BackgroundWater bugs in general play an important role in freshwater ecosystems, and knowledge about them is essential for the study of water biology and the proper management of aquatic habitats. The Neotropical fauna is relatively well known, but the existence of large under-collected areas makes taxonomic and faunistic studies concerning the aquatic and semiaquatic bugs from tropical America urgent.New informationDistributional information is presented for thirty-eight species of Gerromorpha and five Nepomorpha, including first records from the Brazilian states of Bahia (Mesovelia amoena), Ceará (Limnogonus profugus and Rhagovelia whitei), Espírito Santo (R. lucida), Goiás (Halobatopsis platensis and R. zela), Mato Grosso (Rheumatobates bonariensis), Pará (Nerthra terrestris), Paraná (H. spiniventris, Hydrometra fruhstorferi and R. janeira), Piauí (Microvelia ayacuchana, M. pulchella, Neogerris lubricus and Platyvelia brachialis), Rio de Janeiro (Martarega bentoi) and São Paulo (Rheumatobates minutus flavidus); and the Peruvian region of Madre de Dios (Rhagovelia fontanalis).

A Review of Statistical Water Temperature Models

The use of statistical models to simulate or to predict stream water temperature is becoming an increasingly important tool in water resources and aquatic habitat management. This article provides an overview of the existing statistical water temperature models. Different models have been developed and used to analyze water temperature-environmental variables relationship. These are grouped into two major categories: deterministic and statistical/stochastic models. Generally, deterministic models require numerous input data (e.g., depth, amount of shading, wind velocity). Hence, they are more appropriate for analyzing different impact scenarios due to anthropogenic effects (e.g., presence of reservoirs, thermal pollution and deforestation). In contrast to the deterministic models, the main advantage of the statistical models is their relative simplicity and relative minimal data requirement. Parametric models such as linear and non-linear regression are popular methods often used for shorter time scales (e.g., daily, weekly). Ridge regression presents an advantage when the independent variables are highly correlated. The periodic models present advantages in dealing with seasonality that often exists in periodic time series. Non-parametric models (e.g., k-nearest neighbours, artificial neural networks) are better suited for analysis of nonlinear relationships between water temperature and environmental variables. Finally, advantages and disadvantages of existing models and studies are discussed.

Habitat use, migration pattern and population dynamics of chevron snakehead Channa striata in a rainfed rice farming landscape

Habitat use, migration, mortality and growth of the chevron snakehead Channa striata in a rainfed rice farming landscape of north‐east Thailand were studied through a tagging experiment. A total of 751 fish were captured, tagged and released during three distinct events in the late dry season, and in the beginning and at the end of the wet season. Rice fields provided the major wet season habitat for C. striata. Small trap ponds built to provide dry season habitat on farms provided 20% of catches and, if not harvested, could increase recruitment to the spawning stock by >30% despite accounting for <1% of dry season habitat by area. Migrations were localized (mostly <500 m). Up‐migration from perennial to seasonal water bodies at the beginning of the wet season involved longer distances and took place over a longer time than down‐migration at the end of the wet season. Natural mortality rates were extremely high, particularly during the period of down‐migration. Fishing mortality rates were high in absolute terms, but contributed only 6–36% to the total mortality. Growth was seasonal with a maximum towards the end of the wet season. Snakeheads have successfully colonized the rainfed rice farming landscape, where populations can withstand intensive exploitation and respond well to aquatic habitat management on farmland.

Role of grass like species on the aquatic habitat management

Role of grass like species on the aquatic habitat management

Evolution of Marine Artificial Reef Development—A Philosophical Review of Management Strategies

Artificial reefs are a common fishery and aquatic habitat management tool, used in all U.S. coastal states and elsewhere worldwide. Although support for their use is strong among managers and resource users, there is still inadequate scientific information available on their performance in meeting program goals; performance and ecological function information is also weak on many types of natural reefs and fishery-valuable shipwrecks. The wise and responsible use of artificial reefs or habitats by habitat or fishery managers depends on knowing how well they are meeting application objectives; these objectives can be singular or multiple and can involve compliance with laws and regulations. Noncompliance monitoring provides good feedback information to managers and artificial reef designers and planners for continued support and improvement of their efforts. Artificial reef development in the U.S.A. has perhaps reached a state in which an equal effort is needed for construction and for monitoring, assessment, and program fine-tuning for optimum beneficial results. Support for this shift in emphasis can be found in the fact that the continued expansion of artificial reef development has not stopped the decline of many reef fishery resources, such as black sea bass, groupers, snappers, and tautog, or caused many user conflicts. If the artificial reefs and habitats are not completely meeting program expectations, then managers will want to know this and what might be the causes of the shortfall. This paper discusses how monitoring is an essential part of any artificial reef program, just as it is a part of most other fishery and natural resource management efforts, and that there are a range of artificial reef habitat or reef fishery variables that can or should be monitored that provide critical performance information for aquatic resource managers.

Initiating and promoting the aquatic ecosystem health concept: the Society and the Journal

Since the 1970's the management of aquatic habitats has changed from piecemeal monitoring to the ecosystem approach; this was initiated in the North American Great Lakes, comprising social, economic, and environmental aspects. The information included in this paper is based on the presentation made at the ‘Seminar On Ecosystem Approach To Water Management’ held in Oslo, Norway during 1991. Recently, the multidisciplinary, holistic, and integrated concept of ecosystem health has emerged, and is being advanced for the implementation of an ecosystem approach to environmental management, which has resulted in the formation of an international society (Aquatic Ecosystem Health & Management Society) and the publication of a primary journal (Journal of Aquatic Ecosystem Health). The information has been updated to incorporate new developments and recent progress about the Society and the journal since the Oslo Seminar.

Coping with current: Research on running freshwaters in New Zealand, 1967–91

Abstract The New Zealand Journal of Marine and Freshwater Research (NZJMFR) began publication at a time of expanding research activity on running freshwaters in many parts of the world. Since then it has provided an avenue for the publication of a wide range of regionally important studies. Subject areas have included taxonomy, biology of various plant and animal groups, water quality, parasitology, limnological methods, and community ecology. Many papers have reported the findings of research implications for conservation and management of aquatic habitats and biota; others have been concerned with the expansion and testing of ecological theory. In this review, the development of three broad themes within the pages of the journal is discussed: (1) water quality, land‐water interactions, and in‐stream communities; (2) habitat requirements of native fishes and invertebrates; and (3) developments in our understanding of stream ecosystem structure and function.

Use of a municipal environmental quality index for understanding and management of aquatic habitats and fish populations

This study describes the use of a technique developed to assess environmental quality in a municipality. The Environmental Quality Index (EQI) is a tool that can aid land‐use planning, permitting a maximum understanding of the implications for the ecology of an area. A matrix shows the status of each of a series of environmental parameters at each time that an EQI is formulated. Time series analysis is used to quantify environmental impacts on a discrete community's ecosystem: this process allows the graphing of the dynamics of a changing natural resource. Thus, correlation of abiotic changes can be made with changes in biota: for instance, a correlation between proximity to effluents from sewage treatment plants and fish and aquatic plant species diversity is useful information in the managcrnent of fishery resources. Similarly, knowledge of the rate of shift from lotic to lentic waters, due to increased impounding, and its relationship to aquatic plant species diversity is important for land‐use planners who are sensitive to environmental considerations. Decisions made with environmental preservation in mind will help to maintain high quality aquatic habitats.

Aquatic Habitat Analysis as an Element of Water Resources Planning and Management

With increased emphasis on environmental quality objectives in water resources planning and management, past practices of simply considering water quality as the only environmental quality objective are inappropriate. Expanded environmental quality objectives include maintenance of high quality aquatic habitat. Water resource systems must provide both physical and chemical conditions appropriate for the propagation and maintenance of healthy diverse aquatic communities. Managing water resources to provide high quality habitat involves planning to meet both water quality and water quantity objectives. Existing technology based water quality controls and stream based water quality criteria can now be supplemented by aquatic habitat management. An approach to aquatic habitat management is illustrated by use of the Incremental Methodology developed by the U. S. Fish and Wildlife Service. The Incremental Methodology uses measures of aquatic habitat to assess instream flows required for by aquatic life. Thus the range of environmental quality objectives in resources planning and management is expanded by application of these methods to include aquatic habitat as well as water quality management. Methods used to determine instream flow needs for rivers in Illinois are reviewed, and the use of this information in developing regulations limiting water extraction for off stream use are described. Aquatic habitat based management is shown to provide workable methods to meet expanded environmental quality objectives in water resources planning and management.