River restoration for macroinvertebrate communities in lowland rivers: insights from restorations of the Shibetsu River,north Japan

Because of human impacts, lowland rivers are among the most degraded running water ecosystems, with their floodplains being the center of human activity. Recently, many programs to restore running water ecosystems have been undertaken using various methods in streams and rivers of North America, Europe, and Far East Asia. However, research and knowledge on the effects of river restoration in lowland rivers are limited around the world. The restoration project involving the first reconstruction of a meandering channel in Asia has been conducted in a lowland river section of the Shibetsu River, northern Japan. We review the geomorphologic and hydraulic characteristics of lowland rivers and their environments for macroinvertebrates and discuss approaches to restoring macroinvertebrate communities in lowland rivers, using insights from the restoration project in the Shibetsu River. It is concluded that the recovery of macroinvertebrate assemblages in channelized lowland rivers requires the implementation of restoration methods to create stable substrates.     

The significance of meandering channel to habitat diversity and fish assemblage: a case study in the Shibetsu River,northern Japan

This study examined the structure and function of habitats for fish, the contribution to fish populations, and the effects of channel modification on habitats and fish populations in the lowland meandering Shibetsu River, northern Japan. Electrofishing and environmental measurements were conducted in bank areas of habitats constituting natural meandering and modified reaches. All types of habitats in a meandering reach highly contributed to the fish population(s). In particular, the contributions of lateral and wood habitats to fish populations were generally high, despite the low spatial extent of these habitats. The modified reach was simplified and had fewer types of habitats with uniform currents, and there was a low abundance of most fish within these habitats. Abundance of each fish group (taxa) was negatively affected by the changes in the habitats and/or channel shortening (i.e., decrease in the absolute abundance of habitat) due to river modification, which was implemented during 1950–1978. This study suggests that the recovery of all the habitat types is important in meander restoration and that the changes in habitat types and abundance should be examined in monitoring meander restoration and channel shortening.     

The Kissimmee River Restoration Project and Evaluation Program,Florida, U.S.A.

Over the past decade, restoration of the Kissimmee River in central Florida has received considerable attention from local, state, national, and international media. In terms of areal extent, project cost, and ecological evaluation it is one of the largest and most comprehensive river restoration projects in the world. The goal of reestablishing ecological integrity involves restoring the physical attributes and the hydrologic processes that were lost after channelization of the river in the 1960s. The project is expected to restore over 80 km² of floodplain wetlands and reestablish over 70 km of river channel. Restoration construction began in 1999; to date, three construction phases have been completed, with the final phase of construction slated for completion in 2019. Restoration evaluation is widely viewed as a critical component of any restoration project. Equally important is the dissemination of information gained from restoration evaluation programs. This introductory article presents a brief overview of project history and outlines the approach and logic of the Kissimmee River Restoration Evaluation Program. The following papers present the results of ecological studies conducted before and after completion of the first phase of restoration construction. This first phase reestablished flow through 23 km of reconnected river channels and seasonally inundated a large portion (approximately 2,900 ha) of the floodplain within the Phase I project area. Although these studies present interim responses prior to full hydrologic restoration, results suggest that the ecosystem is responding largely as predicted by performance measures developed prior to restoration construction.     

Experimental wood addition in streams: effects on organic matter storage and breakdown

1. Channel complexity affects the physical structure, biotic communities and functioning of stream ecosystems. Large wood (LW) is a key element in the creation and maintenance of physically complex stream channels in forested areas. 2. In an attempt to enhance stream habitat quality and ecosystem functioning and to reduce inputs of organic matter to a downstream reservoir, LW was experimentally introduced into four mountain streams in the Basque Country (northern Spain), ranging in channel width from 3 to 13 m. Following a before–after/control–impact (BACI) design, streams were monitored during 1 year prior to wood addition and during 2 years after addition in one control and one experimental reach per stream. 3. Areal cover of benthic organic matter in the entire channel was measured from regular transects and the mass of stored organic matter from random Surber samples. Breakdown of organic matter was assessed in litter bag experiments performed with black alder leaves. When 50% of the initial mass in the bags remained, invertebrates associated with leaf bags were collected. 4. Wood placement produced a 2‐ to 70‐fold increase in the storage of organic matter, especially in thick deposits upstream from wood jams, with values in excess of 2 kg AFDM per m² in the small streams. The accumulation of organic matter produced by wood introduction decreased with increasing stream size. 5. Despite the large increase in the availability of organic matter, litter breakdown rates were unaffected by the experimental reaches, suggesting large increases in the total amount of organic matter consumed at the reach scale. 6. Numbers of invertebrates and shredders per gram of leaf litter did not respond to wood addition. Average body mass of invertebrates associated with leaf litter showed a non‐significant decreasing trend, which might reflect increased recruitment. 7. Although the effects of wood addition can depend on wood stability and stream size, adding LW to restore channel complexity can improve environmental conditions for invertebrate communities and affect stream ecosystem functioning, enhancing the efficiency to use organic matter inputs on a reach scale.     

Interim Hydrologic Responses to Phase I of the Kissimmee River Restoration Project,Florida

Hydrologic conditions were evaluated during a 10‐year Interim Period following completion of Phase I of the Kissimmee River Restoration Project and initiation of environmental water releases from upstream to provide adaptive management of flow to the Phase I area. Phase I construction backfilled 13 km of flood control canal C‐38 and redirected flow into 22 km of reconnected river channel. Evaluations focused on five restoration expectations (performance measures) based on pre‐channelization hydrologic data for the Kissimmee River. Environmental releases resulted in more continuous discharge from upstream, but did not affect the magnitude of discharge. After backfilling of C‐38, water levels in the Phase I area varied with discharge and periodically inundated the floodplain. However, the long, annual recession event, characteristic of pre‐channelization, was not reestablished; instead, most Interim Period years had multiple events with shorter durations and faster recession rates. Mean channel water velocity increased during the Interim Period but was not always in the desired range. Hydrologic conditions throughout much of the Phase I area were affected by the backwater effect of the downstream water control structure. Four expectations showed improvements in terms of number of years met; however, none met the expectation targets. The inability to meet expectation targets reflects in part the incomplete or interim status of the restoration project.     

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.     

Evaluation of nutrient retention in four restored Danish riparian wetlands

During the last 15–20 years, re-establishment of freshwater riparian wetlands and remeandering of streams and rivers have been used as a tool to mitigate nutrient load in downstream recipients in Denmark. The results obtained on monitoring four different streams and wetland restoration projects are compared with respect to hydrology, i.e. flow pattern and discharge of ground or surface water, retention of phosphorus (P), and removal of nitrogen (N). Furthermore, the monitoring strategies applied for quantifying the post-restoration nutrient retention are evaluated. The four wetland restoration projects are the Brede River restoration (including river valley groundwater flow, remeandering and inundation), Lyngbygaards River restoration (groundwater flow, irrigation with drainage water, inundation with river water and remeandering), Egeskov fen (fen re-establishment and stream remeandering) and Egebjerg Meadows (fen restoration and hydrological reconnection to Store Hansted River). Retention of phosphorus varied between 0.13 and 10 kg P ha⁻¹ year⁻¹, while the removal of nitrogen varied between 52 and 337 kg N ha⁻¹ year⁻¹. The monitoring strategy chosen was not optimal at all sites and would have benefitted from a knowledge on local hydrology and water balances in the area to be restored before planning for the final monitoring design. Furthermore, the outcome concerning P retention would have benefitted from a more frequent sampling strategy.     

Interim Responses of Littoral River Channel Vegetation to Reestablished Flow after Phase I of the Kissimmee River Restoration Project

Measurements of littoral vegetation stands and species‐level surveys of associated plant communities were made in channels of the Kissimmee River from 1998 through 2008, a period that spanned channelized, non‐flowing conditions through 7 years of near‐continuous reestablished flow. Dissected by flood control canal C‐38 in 1971, the river was virtually without flow until early 2001, when Phase I of the Kissimmee River Restoration Project (KRRP) reestablished flow to a central section of river channel. This study evaluated the effects of reestablished flow on littoral vegetation in river channels as an indicator of system status and progress toward the project goal of ecological integrity. Predictions of vegetation response to reestablished flow included reduction in the width of vegetation stands, and changes in the growth‐form composition of littoral stands from near‐equal dominance by floating and emergent species to overwhelming dominance by emergent growth forms. Variables included plant cover by species and growth‐form, width of vegetation stands, and vegetated percentage of channel. Under the currently incomplete (interim) status of the KRRP, results for littoral vegetation stands indicate trends in the predicted directions of change, and three of four predicted changes have occurred. Vegetation stand widths decreased substantially and littoral plant communities became heavily dominated by emergent species; BACIPS (before‐after‐control‐impact‐paired series) analyses indicated significant restoration effects for most littoral stand metrics.     

鄱阳湖水利枢纽工程建设对草鱼江湖洄游潜在的影响

鄱阳湖是长江四大家鱼索饵、育肥的重要场所,近年来鄱阳湖出现了枯水季水位严重降低、枯水期延长、湿地面积缩小的现象。为解决鄱阳湖水资源、水文、水生态等问题,建议在鄱阳湖入江水道兴建控制闸水利枢纽。然而,拟建的水利枢纽工程将打破鄱阳湖与长江的天然连通性,可能会对四大鱼类洄游过程产生影响。通过构建二维和三维水动力模型,分析鄱阳湖水利枢纽建设后入江水道与枢纽洄游通道的水动力学特征,结合实验和文献获得的草鱼幼鱼和成鱼游泳能力参数,阐明了枢纽建设对草鱼洄游的影响。结果表明:在设计调度模式下,草鱼幼鱼入湖期间,湖口段适宜通过天数达到83.74%以上,说明湖口及入江水道的水动力条件对洄游的影响较小,同时,枢纽工程处在过鱼高峰期仍能保持较高的过闸效率;草鱼成鱼出湖期间,丰、平水年闸前水动力条件对洄游的影响较小,仅在枯水年闸前流速几乎静止,草鱼适宜出湖天数偏低。在该调度模式下,水利枢纽建设运行后鄱阳湖整体水动力条件能够满足草鱼洄游需求。目前设计的鱼道在高、低水位时期均出现局部流速过大的现象,不满足过鱼条件。从四大家鱼江湖洄游的角度为鄱阳湖水利枢纽工程设计和运行提供科学参考。     

Interim Response of Dissolved Oxygen to Reestablished Flow in the Kissimmee River,Florida, U.S.A.

Restoration of the Kissimmee River should have multiple ecological benefits including improved dissolved oxygen (DO) within the river channel. Channelization of the Kissimmee River virtually eliminated flow through the natural river channel. After channelization, chronically low DO concentrations were observed in the stagnant remnant channel. Although no DO data from before channelization exist, reference estimates of pre‐channelization conditions were derived from seven relatively unimpacted streams. Stations along the Kissimmee River were sampled for 3 years before construction of the first phase of the restoration project began and for up to 8 years after the completion of construction. After Phase I construction, DO concentrations in the area of the river channel to which flow had been restored increased significantly from 2.2 to 4.9 mg/L, which is similar to DO concentrations observed in the reference streams. Mean DO concentrations for the reference streams ranged from 4.6 to 6.7 mg/L. Comparison of reference data to data from the pre‐Phase I and post‐Phase I system suggests that channelization had a negative impact on DO and that DO concentrations in the post‐Phase I Kissimmee River channel have made a significant recovery. Long‐term data trends demonstrate that DO concentrations can be negatively impacted by high flow events and that recovery from these events is generally quick, suggesting some degree of resilience in the system.     

Patch-specific spawning is linked to restoration of a sediment-disturbed lowland river,south-eastern Australia

Landscape-scale, terrestrial modifications of catchments can increase river sediment loads. In some rivers, the development of ‘sand-slugs’ (i.e. discrete slugs of travelling sand particles) subsequently alters habitat structure with links to declines in regional fish diversity. Increasingly, river channel restoration is being used to conserve biodiversity in sediment-disturbed rivers, but there are few examples to guide restoration efforts. In particular, few studies examine the effect of restoration on ecological processes such as spawning. We report on a trial restoration procedure, consisting of sediment extraction and woody debris replacement undertaken in two 1500 m reaches of the Glenelg River, south-eastern Australia. We aimed to examine the association between reach-scale restoration and fish spawning, predicting that reconstructed channel types (pools and runs) would be used more frequently than corresponding un-modified channel types for spawning. Artificial (polyvinylchloride (PVC) tubes) and natural (small woody debris) spawning substrates were used to examine the association of fish spawning with reach and channel type. Restoration increased wood volume, but only increased average run depth at one reach. Species including Gadopsis marmoratus, Philypnodon grandiceps, Hypseleotris spp., Nannoperca variegata and Cherax destructor were observed within spawning substrates, but only P. grandiceps frequently spawned on PVC tubes and sparsely on small woody debris substrates. Spawning frequency varied between reach and channel types, with pools in both restored and un-manipulated reaches used more frequently than runs. Restored pools were less frequently used than un-manipulated pools, but restored runs were used up to 6 times more frequently than un-manipulated runs, indicating that restoration of the shallowest parts of the channel increased spawning opportunities for P. grandiceps. This type of channel restoration may facilitate ecological processes that underpin the persistence of riverine fish populations.     

Geomorphic Responses to Interim Hydrology Following Phase I of the Kissimmee River Restoration Project,Florida

Channelization of the Kissimmee River eliminated flow through the river channel, which allowed the formation of a largely organic deposition layer (ODL) on the river channel bed and stopped active sand transport needed to maintain point bars on meander bends. In 2001, completion of the first phase of dechannelization for the Kissimmee River Restoration Project (KRRP) reestablished flow to the river channel in the Phase I area. This study evaluated changes in the ODL and the number of meander bends with active point bar development (MBPB) following Phase I of dechannelization. Evaluations involved comparing interim measurements made after flow was reestablished to the river channel in the Phase I area but before full completion of KRRP with (a) baseline measurements made before dechannelization and (b) predicted changes based on reference measurements representing the pre‐channelization system. ODL thickness was measured in core samples on fixed transects perpendicular to the river channel. The ODL was thinner during the Interim Period than the Baseline Period and this decrease exceeded the expected change predicted from the reference condition. MBPB was assessed with aerial photography. MBPB increased from the baseline measurement of 0 bends to interim measurements of 27 bends in 2002 and 72 bends in 2009, approximating the increase predicted from the reference condition. The decrease in ODL thickness and the increase in MBPB to levels that meet or approximate the reference condition indicate that these aspects of the river channel are recovering following reestablishment of flow.     

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.     

南水北调中线干渠两个水工构筑物对着生藻类群落的影响

在南水北调中线干渠两个水工构筑物沙河渡槽与穿黄工程渠段分别设置沙河渡槽上游明渠、沙河渡槽入口、沙河渡槽出口、穿黄工程入口、穿黄工程出口、穿黄工程下游明渠和穿黄工程下游沁河倒虹吸7个监测位点,对着生藻类群落与水质指标进行了原位同步监测。结果表明:监测位点的蓝藻优势种有鞘丝藻(Leptolyngbya sp.)、聚球藻(Synechococcus sp.)、眉藻(Calothrix sp.)、席藻(Phormidium sp.)、集胞藻(Synechocystis sp.)和拟色球藻(Chroococcidiopsis sp.)等;真核藻类优势种有链带藻(Desmodesmus sp.)、土佐牧野藻(Makinoella sp.)、芒球藻(Radiococcus sp.)、盘星藻(Monactinus sp.)、卵囊藻(Oocystella sp.)、菱形藻(Nitzschia sp.)、针杆藻(Synedra sp.)和肘形藻(Ulnaria sp.)等。经过渡槽后藻类生物量下降50%,藻类种类数下降16%;经过穿黄工程后藻类生物量下降80%,藻类种类数下降18%。经过沙河渡槽后,真核藻...     

Some Suggested Guidelines for Geomorphic Aspects of Anadromous Salmonid Habitat Restoration Proposals

Proposals to improve fish habitat for anadromous salmonids by modifying channel form or substrate must be justified based on geomorphology as well as biology, because geomorphic factors often cause such projects to fail. Proposals should address the geomorphic setting at the watershed scale, by specifying changes in flow regime or sediment yield through tools such as a sediment budget. Proposals should also address geomorphic setting and process at the reach scale, indicating the basis for design channel form and dimensions, calculating the frequency of bed mobilization, and assessing existing gravel quality for spawning habitat enhancement projects. Proposals should include explicit provisions for post‐project performance evaluation, including adequate baseline data to permit project‐induced changes to be quantified. Restoration projects also require clear objectives and adequate funding for long‐term monitoring, and generally would benefit from an adaptive management approach to implementation and evaluation.     

Interim Responses of Benthic and Snag‐Dwelling Macroinvertebrates to Reestablished Flow and Habitat Structure in the Kissimmee River,Florida, U.S.A.

A critical component in the effort to restore the Kissimmee River ecosystem is the reestablishment of an aquatic invertebrate community typical of free‐flowing rivers of the southeastern United States. This article evaluates early responses of benthic and snag‐dwelling macroinvertebrates to restoration of flow and habitat structure following Phase I construction (interim period) of the Kissimmee River Restoration Project. Replicate benthic and snag samples were collected from remnant river channels in Pool A (Control site), and Pool C, the site of the first phase of restoration (Impact site). Samples were collected quarterly for 2 years prior to construction (baseline) and monthly or quarterly for 3 years following Phase I construction and restoration of flow. Baseline benthic data indicate a community dominated by taxa tolerant of organic pollution and low levels of dissolved oxygen, including the dipterans Chaoborus americanus (Chaoboridae) and the Chironomus/Goeldichironomus group (Chironomidae). Baseline snag data indicate a community dominated by gathering‐collectors, shredders, and scrapers. Passive filtering‐collector invertebrates were rare. Following restoration of flow, benthic invertebrate communities are numerically dominated by lotic taxa, including bivalves and sand‐dwelling chironomids (e.g. Polypedilum spp., Cryptochironomus spp., and Tanytarsini). Snags within the Phase I area support an invertebrate community dominated by passive filtering‐collectors including Rheotanytarsus spp. (Chironomidae) and Cheumatopsyche spp. (Hydropsychidae). Results indicate that restoration of flow has resulted in ecologically significant changes to the river habitat template not observed in Pool A. Observed shifts in benthic and snag macroinvertebrate community structure support previously developed hypotheses for macroinvertebrate responses to hydrologic restoration.     

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.     

Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential

We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW). For that purpose EW and LW widths and carbon isotope discrimination for the period 1970–2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August) climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and carbon isotope discrimination provides complementary information in Q. robur dendroecology.     

Demonstration of migration of juvenile cyprinid fish using parasite biomarkers

Migration of juvenile (0+) cyprinid fish from the Kiso River to experimental streams in the Aqua Restoration Research Center was demonstrated by the presence of parasites on fish. The experimental streams were located a minimum of 0.7 km from the main reach of the Kiso River, and they were connected via a tributary (Shinsakai River). The experimental streams were used as a spawning site and a nursery for juveniles, similar to the use of a temporary water body such as a paddy field. A digenean trematode (Centrocestus spp.) and the glochidia of unionid bivalves, both of which did not infect fish in the experimental streams or in the Shinsakai River, were used as marker parasites. Their presence indicated that the fish moved in the experimental streams from the Kiso River. For both fish species (Gnathopogon elongatus and Zacco platypus) assessed in this study, juveniles greater than 20–30 mm standard length could migrate from the Kiso River. This study showed that temporary waters are important as a nursery for juvenile fish, for whether or not a species spawns there. For the conservation of fish populations, it is important that temporary waters that are used as a nursery are connected with a permanent water area by a channel, through which not only adults, but also juvenile fish can migrate.     

Interim Responses of Floodplain Wetland Vegetation to Phase I of the Kissimmee River Restoration Project: Comparisons of Vegetation Maps from Five Periods in the River's History

Phase I of the Kissimmee River Restoration Project (KRRP) reestablished intermittent inundation of the river's floodplain by backfilling 12 km of the C‐38 flood control canal in 2001. We compared floodplain vegetation maps based on 2003 and 2008 aerial imagery (2 and 7 years following completion of Phase I, respectively) to vegetation maps from 1954 (pre‐channelization), 1974 (3 years after channelization), and 1996 (25 years after channelization) to evaluate broad‐scale vegetation responses to Phase I restoration. Results indicate that the extent of wetland plant communities expanded rapidly, more than doubling in area within 2 years after completion of Phase I, and that by 2008 wetlands had nearly recovered to pre‐channelization levels. However, full reestablishment of the pre‐channelization wetland mosaic has not yet occurred. Prior to channelization, much of the floodplain was dominated by a broadleaf marsh (BLM) community associated with extended, deep annual flooding, while shorter‐hydroperiod communities dominated the floodplain in 2003 and 2008. Prior to restoration construction, the reestablishment of BLM was predicted to be slow because suitable hydrology is dependent on project components that will not be in place until all restoration components are completed (projected for 2019). Hydrologic data indicate that the duration and variability of floodplain inundation have not yet achieved restoration targets over the entire Phase I study area. Other factors affecting vegetation responses are likely involved, including the age and viability of soil seed banks, the rarity of relict propagule sources following the channelized period, and competition from an invasive wetland shrub species.