密西西比河干流大坝建设对鱼类的影响及保护措施

如何减轻大坝阻隔对鱼类等水生生物的影响以及制定有效的恢复措施一直是河流生态保护的主要内容。文章通过文献调研、资料收集等方式对美国密西西比河干流大坝建设状况及其对鱼类的影响进行梳理, 总结了当前美国所采取的相关保护措施和效果。统计结果显示, 密西西比河干流共建有梯级闸坝41座, 均分布在干流的上游, 多数大坝坝高不超过15 m, 库容小于0.3 km3。这些弱调蓄能力的低水头坝阻隔了密西西比河鱼类洄游, 但目前仍未修建过鱼设施。相关研究证实, 密西西比河洄游性鱼类可以利用泄水闸门完成上行和下行, 但过鱼效率随着大坝梯级的递增逐级下降, 尤其是鲟类, 仍难以抑制其种群的衰退。受长期蓄水影响, 密西西比河上游鱼类群落产生了空间分化, 但仍保持着较高的物种多样性。1986和2000年, 美国分别实施了上密西西比河生态系统环境管理计划(UMRS-EMP)和上密西西比河生态恢复和维持策略(UMRS-RMS), 采用渔业资源长期监测计划(LTRMP)及9项栖息地修复措施, 从生态系统层面保障了密西西比河鱼类资源的持续稳定。这种系统性修复方式可为我国筑坝河流鱼类资源保护与河流生态修复提供参考和示范。     

The Significance of Meander Restoration for the Hydrogeomorphology and Recovery of Wetland Organisms in the Kushiro River,a Lowland River in Japan

The meanders and floodplains of the Kushiro River were restored in March 2011. A 1.6‐km stretch of the straightened main channel was remeandered by reconnecting the cutoff former channel and backfilling the straightened reach, and a 2.4‐km meander channel was restored. Additionally, flood levees were removed to promote river–floodplain interactions. There were four objectives of this restoration project: to restore the in‐stream habitat for native fish and invertebrates; to restore floodplain vegetation by increasing flooding frequency and raising the groundwater table; to reduce sediment and nutrient loads in the core wetland areas; to restore a river–floodplain landscape typical to naturally meandering rivers. In this project, not only the natural landscape of a meandering river but also its function was successfully restored. The monitoring results indicated that these goals were likely achieved in the short term after the restoration. The abundance and species richness of fish and invertebrate species increased, most likely because the lentic species that formerly inhabited the cutoff channel remained in the backwater and deep pools created in the restored reach. In addition, lotic species immigrated from neighboring reaches. The removal of flood levees and backfilling of the formerly straightened reach were very effective in increasing the frequency of flooding over the floodplains and raising the water table. The wetland vegetation recovered rapidly 1 year after the completion of the meander restoration. Sediment‐laden floodwater spread over the floodplain, and approximately 80–90% of the fine sediment carried by the water was filtered out by the wetland vegetation.     

A spatial simulation model for forest succession in the Upper Mississippi River floodplain

A Markov-chain transition model (FORSUM) and Monte Carlo simulations were used to simulate the succession patterns and predict a long-term impact of flood on the forest structure and growth in the floodplain of the Upper Mississippi River and Illinois River. Model variables, probabilities, functions, and parameters were derived from the analysis of two comprehensive field surveys conducted in this floodplain. This modeling approach describes the establishment, growth, competition, and death of individual trees for modeled species on a 10,000-ha landscape with spatial resolution of 1 ha. The succession characteristics of each Monte Carlo simulation are summed up to describe forest development and dynamics on a landscape level. FORSUM simulated the impacts of flood intensity and frequency on species composition and dynamics in the Upper Mississippi River floodplain ecosystem. The model provides a useful tool for testing hypotheses about forest succession and enables ecologists and managers to evaluate the impacts of flood disturbances and ecosystem restoration on forest succession. The simulation results suggest that the Markov-chain Monte Carlo method is an efficient tool to help organize the existing data and knowledge of forest succession into a system of quantitative predictions for the Upper Mississippi River floodplain ecosystem.     

Otolith trace element and stable isotopic compositions differentiate fishes from the Middle Mississippi River, its tributaries, and floodplain lakes

Naturally occurring stable isotope and trace elemental markers in otoliths have emerged as powerful tools for determining natal origins and environmental history of fishes in a variety of marine and freshwater environments. However, few studies have examined the applicability of this technique in large river-floodplain ecosystems. This study evaluated otolith microchemistry and stable isotopic composition as tools for determining environmental history of fishes in the Middle Mississippi River, its tributaries, and floodplain lakes in Illinois and Missouri, USA. Fishes were collected from 14 sites and water samples obtained from 16 sites during summer and fall 2006 and spring 2007. Otolith and water samples were analyzed for stable oxygen isotopic composition (δ¹⁸O) and concentrations of a suite of trace elements; otoliths were also analyzed for carbon isotopic composition (δ¹³C). Tributaries, floodplain lakes, and the Mississippi and Lower Missouri Rivers possessed distinct isotopic and elemental signatures that were reflected in fish otoliths. Fish from tributaries on the Missouri and Illinois sides of the middle Mississippi River could also be distinguished from one another by their elemental and isotopic fingerprints. Linear discriminant function analysis of otolith chemical signatures indicated that fish could be classified back to their environment of capture (Mississippi River, floodplain lake, tributary on the Illinois or Missouri side of the Mississippi River, or lower Missouri River) with 71–100% accuracy. This study demonstrates the potential applicability of otolith microchemistry and stable isotope analyses to determine natal origins and describe environmental history of fishes in the Middle Mississippi River, its tributaries, and floodplain lakes. The ability to reconstruct environmental history of individual fish using naturally occurring isotopic markers in otoliths may also facilitate efforts to quantify nutrient and energy subsidies to the Mississippi River provided by fishes that emigrate from floodplain lakes or tributaries.     

River Enhancement in the Upper Mississippi River Basin: Approaches Based on River Uses, Alterations, and Management Agencies

The Upper Mississippi River is characterized by a series of locks and dams, shallow impoundments, and thousands of river channelization structures that facilitate commercial navigation between Minneapolis, Minnesota, and Cairo, Illinois. Agriculture and urban development over the past 200 years have degraded water quality and increased the rate of sediment and nutrient delivery to surface waters. River enhancement has become an important management tool employed to address causes and effects of surface water degradation and river modification in the Upper Mississippi River Basin. We report information on individual river enhancement projects and contrast project densities, goals, activities, monitoring, and cost between commercially non‐navigated and navigated rivers (Non‐navigated and Navigated Rivers, respectively). The total number of river enhancement projects collected during this effort was 62,108. Cost of all projects reporting spending between 1972 and 2006 was about US$1.6 billion. Water quality management was the most cited project goal within the basin. Other important goals in Navigated Rivers included in‐stream habitat improvement and flow modification. Most projects collected for Non‐navigated Rivers and their watersheds originated from the U.S. Department of Agriculture (USDA). The U.S. Army Corps of Engineers and the USDA were important sources for projects in Navigated Rivers. Collaborative efforts between agencies that implement projects in Non‐navigated and Navigated Rivers may be needed to more effectively address river impairment. However, the current state of data sources tracking river enhancement projects deters efficient and broad‐scale integration.     

Assessing Habitat Suitability for Juvenile Atlantic Salmon in Relation to In‐Stream Restoration and Discharge Variability

In‐stream restoration often aims at increasing the availability of the stream habitat suitable for salmonid fishes, thus creating potential for increased fish abundance. We assessed the success of in‐stream restoration of River Kiiminkijoki, northern Finland, by combining River2D habitat hydraulic modeling and fish density monitoring at the same sites, with data from multiple restored and reference reaches for 3 years both before and after restoration. We modeled the effects of restoration on the area suitable (weighted usable area, WUA) for juvenile Atlantic salmon from post‐hatching to age‐1 fish. Wetted width in the restored reaches increased by 8.1% on average compared with only ?0.2% change in the reference reaches. Habitat time series across 10 years showed significant increases in the amount of suitable habitat under summer conditions for both age‐0 and age‐1 salmon. However, improvement of overwintering habitats was marginal or nonexistent. Densities of age‐1 salmon showed no response to restoration. Low river discharge during the winter was correlated with low salmon densities the following summer. It thus appears that variability in wintertime discharge, and associated high interannual variation of WUA values, overrode the almost 20% increase in average post‐ versus pre‐restoration summertime WUA. Our study shows that the combination of hydraulic modeling and biological monitoring is a promising approach to stream restoration assessment.     

Using stressor gradients to determine reference expectations for great river fish assemblages

We describe a simple empirical modeling approach for determining least-disturbed conditions for the great rivers of the Upper Mississippi River basin: Missouri, Upper Mississippi, and Ohio Rivers. We used multivariate analysis to identify reference strata (reaches for which a single reference expectation was appropriate) on each river. Strata included the Upper Missouri, Lower Missouri, impounded Upper Mississippi, unimpounded Upper Mississippi, and the Ohio River. We created a multimetric stressor gradient for each stratum using a suite of site- and landscape-scale metrics. Site-scale metrics included water chemistry, aquatic and riparian habitat, and human disturbance metrics. Landscape-scale metrics included land use, land cover, and proximity to human disturbance. The gradient was scaled from 0 (least stressed) to 1 (most stressed). Multimetric indices of condition based on fish assemblages for the Lower Missouri and Upper Mississippi River were responsive to stressor gradients based on 18–24 abiotic stressor metrics. Ohio River fish assemblages were responsive to a hand-picked three-metric gradient. We used the y-intercept of quantile regression to predict the fish index value for a stressor gradient value of 0 (the fish index value at a site with the lowest mean stressor gradient score in the reference stratum) which we designated as least-disturbed condition for the fish index for that stratum. We trisected the difference between predicted least-disturbed condition (ceiling value) and a floor value set at the 5th percentile of the sample to create thresholds for three condition classes: least-disturbed, intermediate, and most-disturbed. Based on the derived condition class thresholds for the fish index, 10% (by length) of the Lower Missouri was in least-disturbed condition, compared to 14% of the Ohio River and 19% of the impounded Upper Mississippi River. The index of condition exhibited longitudinal variation that was associated with the location of major urban areas along each river. We conclude that empirical modeling based on an abiotic stressor gradient can provide an alternative approach for deriving internal reference expectations for great rivers with few, if any, minimally disturbed sites.     

An assessment of the aquatic and wetland vegetation of the Upper Mississippi River

Illinois, Iowa, Minnesota, Missouri, and Wisconsin have strong botanical traditions that have resulted in a macrophyte literature which documents the identity, taxonomy, floristics, and ecology of aquatic macrophytes and wetland vegetation of the Upper Mississippi River and its floodplain. These findings are reviewed with respect to floristics, vegetation dynamics (patterns, history, production and management), and environmental changes that impact vegetation. Aspects requiring future study are noted to direct subsequent investigations.     

Evaluating the ecological performance of wetland restoration in the Yellow River Delta,China

Long-term monitoring is essential to evaluate the effects of wetland restoration projects. A monitoring program before and after restoration has been carried out in the study area located in the Yellow River Delta since 2001. Water quality, soil salinity, soil organic matter, plant community, and bird species were chosen as indicators in this program. During the past seven years, the restored wetland showed increasing efficiency in reducing water pollution levels. Soil quality was constantly improved through salinity reduction and soil organic matter accumulation. The vegetation community quickly re-established after the restoration was initiated in 2002. The restored vegetation communities provide favorable habitat conditions for birds and thirty-seven bird species were observed in October 2007. Based on Canonical Correspondence Analysis (CCA), plant species and vegetation community are mainly influenced by soil salinity and water depth. These indicate that conducting freshwater to the project area is an efficient measure for vegetation restoration. While monitoring results show that the restoration project had positive effects on the wetland ecosystem over the past seven years, two issues remain for future study: (1) the contribution of harvesting vegetation to stabilizing nutrient removal rate and the accumulation of soil organic matter in the soil; and (2) the effects of excessive propagation of Phragmites australis on spatial heterogeneity and plant diversity.     

Long-term changes in fish community structure in relation to the establishment of Asian carps in a large floodplain river

The Upper Mississippi River System, including the Illinois River, has been invaded by a number of nonnative species including silver carp Hypophthalmichthys molitirx and bighead carp H. nobilis, collectively referred to here as Asian carps. Silver carp densities in the Illinois River have increased dramatically and now represent some of the highest densities of wild silver carp anywhere in the world. Asian carps have the potential to alter existing ecosystems by consuming planktonic resources and therefore, could have the ability to alter existing fish communities as most fishes are dependent on planktonic resources during early development. However, identifying the relationship of fish community structure to the establishment of Asian carps has yet to be thoroughly investigated. Using long-term fish community data collected by the Upper Mississippi River Restoration’s Long Term Resource Monitoring element, we investigate changes in fish community structure pre- and post-establishment of Asian carps. Significant differences in the pre- and post-establishment communities were observed for the majority of gears and habitats. Species contributing to changes between establishment periods included most sportfish species and catostomids, which were less abundant post-establishment of Asian carps, while shortnose gar, grass carp, and emerald shiner were more abundant. While our analyses show Asian carps are likely contributing to major differences in fish community structure, future research and long-term monitoring should investigate the mechanisms and interactions responsible for community changes as well as identifying any potential concurrent or confounding factors such as changes in river hydrology or sedimentation.     

Fish species diversity among spatial scales of altered temperate rivers

Aim The alteration of flowing systems over the past century has led to significant changes to the processes that drive these complex environments as well as to the scales at which these processes act. Recently, efforts have begun in earnest to restore some semblance of ecosystem diversity, but there is little understanding of exactly on what spatial scale or scales biotic diversity is responding. We investigated the manner in which fish diversity is partitioned at multiple spatial scales in two rivers in the central United States. Location The Missouri and Illinois rivers of the central United States. Methods We analysed how fish diversity was partitioned within the Illinois River and Missouri River systems by sampling each river under hierarchical frameworks that allowed analysis at section (large), reach (intermediate), and site (small) scales. We tested the hypothesis that there are scale‐dependent responses of fish diversity using an additive partitioning approach. Results Site alpha diversity was significantly higher than expected in both the Illinois and Missouri rivers. The relative contribution of alpha diversity to total diversity at a given spatial scale increased for the Illinois River, but not for the Missouri River, in that the highest alpha diversity contribution peaked at the reach scale. Diversity patterns from both rivers suggest that diversity at the site scale plays a significant role in determining the overall diversity in these systems. However, there is a substantial contribution at larger scales that warrants consideration when attempts are being made to protect or restore diversity and other ecosystem parameters. Main conclusions Understanding the variation of diversity in riverine systems is crucial for providing insight not only into how biotic communities respond to scale‐dependent factors, but also into the underlying abiotic and biotic factors that generate patterns of diversity across scales. These insights, in turn, are important for ensuring that restoration and management activities are targeting the appropriate scales for remediation. A lack of understanding of this issue could have negative outcomes for the recovery of a community in a restoration scenario, as well as resulting in a low economic return on restoration investments, which could hinder future efforts.     

A scientific basis for restoring fish spawning habitat in the St. Clair and Detroit Rivers of the Laurentian Great Lakes

Loss of functional habitat in riverine systems is a global fisheries issue. Few studies, however, describe the decision‐making approach taken to abate loss of fish spawning habitat. Numerous habitat restoration efforts are underway and documentation of successful restoration techniques for spawning habitat of desirable fish species in large rivers connecting the Laurentian Great Lakes are reported here. In 2003, to compensate for the loss of fish spawning habitat in the St. Clair and Detroit Rivers that connect the Great Lakes Huron and Erie, an international partnership of state, federal, and academic scientists began restoring fish spawning habitat in both of these rivers. Using an adaptive management approach, we created 1,100 m² of productive fish spawning habitat near Belle Isle in the Detroit River in 2004; 3,300 m² of fish spawning habitat near Fighting Island in the Detroit River in 2008; and 4,000 m² of fish spawning habitat in the Middle Channel of the St. Clair River in 2012. Here, we describe the adaptive‐feedback management approach that we used to guide our decision making during all phases of spawning habitat restoration, including problem identification, team building, hypothesis development, strategy development, prioritization of physical and biological imperatives, project implementation, habitat construction, monitoring of fish use of the constructed spawning habitats, and communication of research results. Numerous scientific and economic lessons learned from 10 years of planning, building, and assessing fish use of these three fish spawning habitat restoration projects are summarized in this article.     

Seasonal zooplankton dynamics in main channel and backwater habitats of the Upper Mississippi River

This study used stratified random sampling to examine the spatial and temporal distribution of zooplankton communities in a large floodplain river (Mississippi River, USA). Potential mechanisms controlling zooplankton abundance and community structure were considered. Main channel and backwater habitats included in this study differed between a turbid upper pool reach where aquatic macrophytes were sparse and a lower pool reach which was considerably less turbid and had extensive aquatic macrophyte coverage. Samples were collected monthly during the summer over a 2-year period and multivariate analysis was used to examine the spatial and temporal distribution of zooplankton. Significant differences were found in zooplankton density and community composition among habitats and reaches within the pool. Rotifers were the dominant taxa and seasonality was pronounced, with peak densities often occurring in late-spring. Community structure varied by habitat and reach, which suggests that water quality, physical habitat characteristics, presence of aquatic macrophytes, and zooplankton sources can all influence the zooplankton communities of the Upper Mississippi River. Characterization of the zooplankton communities provides a basis for understanding changes in the river ecosystem and examination of zooplankton communities among habitats provides insight into the mechanisms affecting zooplankton dynamics.     

Long-Term Monitoring and Evaluation of the Lower Red River Meadow Restoration Project, Idaho, U.S.A.

Although public and financial support for stream restoration projects is increasing, long‐term monitoring and reporting of project successes and failures are limited. We present the initial results of a long‐term monitoring program for the Lower Red River Meadow Restoration Project in north‐central Idaho, U.S.A. We evaluate a natural channel design’s effectiveness in shifting a degraded stream ecosystem onto a path of ecological recovery. Field monitoring and hydrodynamic modeling are used to quantify post‐restoration changes in 17 physical and biological performance indicators. Statistical and ecological significance are evaluated within a framework of clear objectives, expected responses (ecological hypotheses), and performance criteria (reference conditions) to assess post‐restoration changes away from pre‐restoration conditions. Compared to pre‐restoration conditions, we observed ecosystem improvements in channel sinuosity, slope, depth, and water surface elevation; quantity, quality, and diversity of in‐stream habitat and spawning substrate; and bird population numbers and diversity. Modeling documented the potential for enhanced river–floodplain connectivity. Failure to detect either statistically or ecologically significant change in groundwater depth, stream temperature, native riparian cover, and salmonid density is due to a combination of small sample sizes, high interannual variability, external influences, and the early stages of recovery. Unexpected decreases in native riparian cover led to implementation of adaptive management strategies. Challenges included those common to most project‐level monitoring—isolating restoration effects in complex ecosystems, securing long‐term funding, and implementing scientifically rigorous experimental designs. Continued monitoring and adaptive management that support the establishment of mature and dense riparian shrub communities are crucial to overall success of the project.     

上海大莲湖湖滨带湿地的生态修复

采用改变土地利用模式、水系改造和植被配置等技术开展了上海青浦大莲湖湿地修复示范工程。本文从2008年8月到2010年3月跟踪调查了土地利用方式、鸟类群落、两栖爬行类、水质等多类指标来对示范工程进行评估。结果表明,实验区生态系统的生境结构和生物多样性组成都发生了明显的变化。实验区内土地利用由主要以人工养殖鱼塘和林地为主的人工湿地(人工鱼塘占50%,林地占25%),转变为以开放性水域和乔灌草相结合的半自然状态下的自然湿地(明水面面积占30%,各类植被群落占50%,人工鱼塘完全消失),植被从只有片段化林地转变为乔木、灌木丛、草本植物及各类水生植物相结合的格局;工程后鸟类种类和数量均高于工程前(新纪录到11种鸟类),鸟类多样性指数和均匀性指数也有明显增加,其中目标鸟类——雁鸭类新增6种,种类和数量都呈显著增加;两栖爬行类种类变化不大,共记录到6科12种,但整体数量比工程前增长了59.1%;水质指标的变化也很突出,与工程前人工鱼塘相比,实验区内水体中总氮(TN)、硝态氮(NO3-N)、总磷(TP)、叶绿素a(Chla)、高锰酸钾指数(CODMn)等主要指标均有显著下降(P<0.05),水质改善显著。由此说明,修复工程改善了大莲湖湖滨带湿地的生态环境,生物多样性得到较好的恢复,呈现出良好的湿地修复效果。     

Estimating phosphorus retention of existing and restored coastal wetlands in a tributary watershed of the Laurentian Great Lakes in Michigan,USA

Simulation modeling with uncertainty analysis was applied to the question of nonpoint source pollution control through extensive wetland restoration. The model was applied to the Quanicassee River basin, a tributary stream to Saginaw Bay on Lake Huron in northeastern Michigan, USA. An estimate of the role of the existing 695 ha of riverside and lake-side wetlands in the lower Quanicassee River basin suggests that they retain 1.2 metric tons of phosphorus per year (mt P/yr), or 2.5% of the total phosphorus load from the basin. A simple Vollenweider-type model of phosphorus retention by created wetlands, calibrated with 3-years of data from two wetland sites in Midwestern USA, was used to estimate the effect of major wetland restoration in the basin. For a wetland restoration project involving 15% of the Quanicassee River basin or 3,120 ha of wetlands, an estimated 33 mt P/yr could be retained, assuming a proper hydrologic connection between the wetlands and the river. This would represent a reduction of two-thirds of the existing phosphorus load to the Bay from the Quanicassee River basin. Large-scale wetland restoration appears to be a viable management practice for controlling phosphorus and other nonpoint source pollution from entering Saginaw Bay. It is an alternative that meets two major resource goals – developing wetland habitat and controlling pollution to the Great Lakes.     

Autumn use of woody snags by fishes in backwater and channel border habitats of a large river

Snags are important to fish communities in small rivers and streams, but their importance to fishes in large rivers has not been investigated. This study examined snag use by fishes during autumn in backwater and channel border habitats in the upper Mississippi River, and compared these to fish communities in reference sites without snags. Species assemblages differed significantly between backwater and channel border habitats, and between snag and reference sites within the channel border, likely responding to differences in substrate, depth, and current velocity. In both habitats, average fish biomass and abundance were higher (2 to 50 ×) at snag sites than at reference sites, but these differences were significant only for channel border biomass. Fish taxa richness differed between backwater and channel border habitats, but not between snag and reference sites. Most large piscivorous fishes (e.g., Micropterus spp., Stizostedion spp.), several insectivorous fishes (Lepomis macrochirus, Ambloplites rupestris, Minytrema melanops), and a few prey fishes (L. macrochirus, Notropis atherinoides) were significantly more abundant at snag sites than at reference sites, suggesting active selection of snags for foraging or protection. Snag quality, as assessed by a snag rating index, had a direct effect on attracting fish communities with greater biomass, especially within the channel border habitat. These results indicate that snags are important habitat for fish communities in both backwaters and channel border habitats of the upper Mississippi River.     

Conceptual Evaluation of Factors Potentially Affecting Restoration of Habitat Structure within the Channelized Kissimmee River Ecosystem

A critical element of the ongoing effort to restore the ecological integrity of Florida's Kissimmee River ecosystem is the reestablishment of pre-channelization habitat structure and function. Restoration of habitat will form the basis for responses by most biological components of the ecosystem and will provide a key indicator of the success of the restoration effort. This paper evaluates the relative importance of a range of abiotic and biotic habitat parameters in the existing and historic Kissimmee River ecosystem and provides a conceptual framework for predicting expected spatial and temporal responses of river and floodplain habitats to the restoration project. Among the ecological factors and process that influenced the development, dynamics, and maintenance of river and floodplain habitat structure, hydrology is expected to be of central importance in eliciting restoration responses in the Kissimmee River Ecosystem. Based on the assumption that the restoration plan will reestablish historic hydrologic characteristics, predictions are made of expected responses by geomorphic and vegetative components of the Kissimmee River's habitat structure. Recommendations are made regarding key habitat parameters requiring long term tracking and analysis and utilization of a geographic information system(GIS). A hierarchical habitat classification scheme is provided as a foundation for all components of the restoration evaluation program.     

Spatio-temporal changes in habitat potential of endangered freshwater fish in Japan

In recent years, biodiversity conservation and ecosystem restoration have been key issues of watershed management in many countries. To maintain or restore the environmental quality of watersheds, we need to assess the impact of anthropogenic changes on stream ecosystems with accuracy. In addition, watershed conservation planners have to make strategic plans and determine priorities of each conservation activity.

A new monitoring methodology to evaluate the change of habitat condition for freshwater fish based on a predictive habitat model using logistic regression was developed and applied to the whole of Japan. The main contributions of our approach were 1) the construction of a Geographical Information System (GIS) database that integrates many types of data, including freshwater fish species, water quality, habitat fragmentation by damming, geology, and climate; 2) spatial analysis for quantitative assessment and predictive habitat modeling using logistic regression to combine fish survey data and environmental habitat factors to determine critical and major habitat variables for each target fish; and 3) digital mapping and changes detection of fish habitat potential for targeted endangered fish species to show habitat distribution and spatio-temporal changes of habitat potential over a 25-year period (from 1977 to 2002). We found that predicted suitable habitat and actual fish habitat showed high overlap, and that habitat conditions and distribution patterns of target freshwater fish had been affected by major habitat variables to target species respectively.     

An Historical Perspective on the Kissimmee River Restoration Project

This paper reviews the events leading to the channelization of the Kissimmee River, the physical, hydrologic, and biological effects of channelization, and the restoration movement. Between 1962 and 1971, in order to provide flood control for central and southern Florida, the 166 km-long meandering Kissimmee River was transformed into a 90 km-long, 10 meter-deep, 100 meter-wide canal. Channelization and transformation of the Kissimmee River system into a series of impoundments resulted in the loss of 12,000–14,000 ha of wetland habitat, eliminated historic water level fluctuations, and greatly modified flow characteristics. As a result, the biological communities of the river and floodplain system (vegetation, invertebrate, fish, wading bird, and waterfowl) were severely damaged. Following completion of the canal, the U.S. Geological Survey released a report documenting the environmental concerns associated with channelization of the river. This action led to the 1971 Governor's Conference on Water Management in South Florida that produced a consensus to request that steps be taken to restore the fish and wildlife resources and habitat of the Kissimmee basin. In 1976, the Florida Legislature passed the Kissimmee River Restoration Act. As a result, three major restoration and planning studies (first federal feasibility study [1978–1985], the Pool B Demonstration Project [1984–1990], and the second federal feasibility study [1990-present] were initiated (1) to evaluate measures and provide recommendations for restoring flood-plain wetlands and improving water quality within the Kissimmee basin, (2) to assess the feasibility of the recommended dechannelization plan, and (3) to evaluate implementation of the dechannelization plan. The recommended plan calls for the backfilling of over 35 km of C-38, recarving of 14 km of river channel, and removal of two water-control structures and associated levees. Restoration of the Kissimmee River ecosystem will result in the reestablishment of 104 km² of river-floodplain ecosystem, including 70 km of river channel and 11,000 ha of wetland habitat, which is expected to benefit over 320 species of fish and wildlife.