Restoration Of Riparian Zones Research Articles

Scenario Planning Management Actions to Restore Cold Water Stream Habitat: Comparing Mechanistic and Statistical Modeling Approaches

ABSTRACTUnder the United States Clean Water Act, states are required to periodically assess state waters to determine compliance with water quality criteria (including temperature) and then to develop total maximum daily loads (TMDLs) for impaired waters as necessary to bring them into compliance. We compared the performance of mechanistic stream temperature models (HeatSource, QUAL2K, and QUAL2Kw) applied to the mainstem of three TMDL watersheds (Middle Fork John Day, OR; Wind River, WA; South Fork Nooksack, WA) with that of spatial stream network (SSN) models applied to the full watersheds and used these to evaluate the potential effectiveness of restoration strategies. SSN models performed well with slightly lesser accuracy (RMSE = 0.47–0.87) for mainstem predictions than mechanistic models (RMSE = 0.4) but provided additional benefits to inform management, including information on spatial and temporal heterogeneity of restoration effectiveness throughout the watershed. Of the four scenarios considered (restoration of riparian zones to potential natural vegetation, channel narrowing, increasing flow by restricting irrigation withdrawals, and combined applications), riparian zone restoration was consistently the most effective in reducing temperatures at the outlet, mainstem, and throughout the watersheds. Predicted restoration effectiveness for thermal regimes varied significantly both within and among watersheds. A focus on water quality criteria exceedance only at the watershed outlet or along the mainstem reach can obscure knowledge of restoration potential for fish habitat in tributaries and headwaters, potential for creation of thermal refuge areas along the mainstem critical for maintaining migration corridors, and thermal regime heterogeneity across space and time.

Qualidade da água e uso e cobertura do solo na bacia do Ribeirão Ipanema (Bacia do Rio Doce/Brasil): efeitos da urbanização

ABSTRACT We evaluated the water quality conditions and their relationships with the land cover/use throughout the entire Ipanema Stream Watershed (ISW), also considering temporal differences. Thirteen water quality variables were evaluated in fourteen sampling stations located in rural, peri-urban, and urban zones in both dry and rainy seasons from 2015 to 2018. A PCA was performed to detect which variables explain most of the data variability and to detect spatial and/or temporal trends in ISW water quality. The four PCs explained 74% of the data variability, but strong relationships with environmental variables were only observed in the two main components. PC1 was related to nutrients, alkalinity, BOD, electrical conductivity, DO, and pH, while PC2 was related to total suspended solids (TSS) and chlorophyll-a. A spatial pattern related to sampling stations and land uses was observed, but no temporal pattern was identified. Ammoniacal-N and TSS were most important variables (loading values >│0.75│), and showed higher values in urban zone probably due to inadequate sewage discharge. Ipanema Stream did not show a self-purification capacity, and the high TSS concentrations in rural mainstream ask for riparian zone restoration. These management actions for water quality improvement would even contribute to the recovery of Doce River.

Macroinvertebrate conservation in river ecosystems: Challenges, restoration strategies, and integrated management approaches

AbstractRiver ecosystems face growing threats from human‐induced stressors, resulting in habitat degradation and biodiversity loss. Crucial to these ecosystems, macroinvertebrates maintain river health and functioning. In this review, we examine the challenges confronting macroinvertebrates, explore restoration strategies and management approaches, and shed light on knowledge gaps and future research directions. Habitat degradation, water pollution, climate change, and invasive species are discussed as key challenges. Various restoration strategies, such as in‐stream habitat restoration, flow regime restoration, riparian zone restoration, and connectivity restoration, are evaluated for macroinvertebrate conservation. Integrated catchment management, adaptive management, community‐based management, monitoring, and policy integration are highlighted as essential management approaches, and knowledge gaps in long‐term monitoring, innovative restoration techniques, climate change resilience, and policy incorporation are identified as areas calling for further research. Ultimately, a proactive, adaptable, and cooperative approach to river management will ensure macroinvertebrate conservation and sustainable river ecosystems.

A genomic perspective on the conservation status of the endangered Nashville crayfish (Faxonius shoupi)

The Nashville crayfish (Faxonius shoupi, Hobbs 1948) was federally listed as an endangered species in 1986 due to its limited distribution in the Mill Creek watershed; this waterway lies in the rapidly developing Nashville basin and has experienced habitat degradation due to agricultural run-off, contamination, and urban development. Recovery efforts, including dam removal and restoration of riparian zones, have improved conditions in Mill Creek and F. shoupi has increased in numbers and recolonized extirpated stream segments. However, a history of demographic bottlenecks and restricted gene flow may have negatively impacted the long-term recovery of this species. A recently discovered population of F. shoupi in a disjunct segment of the Lower Tennessee River at the Pickwick Tailwater may provide an additional source of genetic variation. Uncertainty surrounding the origins of the Pickwick population and its taxonomic relationship to F. shoupi in Mill Creek raises questions about the conservation and management implications of this population. We used mitochondrial sequencing and SNP genotyping to assess genetic variation and connectivity of F. shoupi in the Mill Creek drainage and to investigate the taxonomy and demographic history of the newly discovered population at Pickwick. We found substantial genetic variation and evidence of connectivity for samples throughout Mill Creek for both mitochondrial and genome-wide SNPs. Our results also suggest a recently severed connection between crayfish in Pickwick and Mill Creek. Unique mitochondrial haplotypes and SNP variation in the Pickwick population highlight the need for prioritizing this population in future conservation and management plans for this species.

Uloga riparijalnih oblasti u invaziji stranih biljnih vrsta

Biological invasions represent one of the defining features of the Anthropocene, causing major problems and incurring significant economic losses worldwide, which are only projected to increase in the future. Riparian zones, as critical transition zones, despite providing numerous ecosystem services, are exposed to a multitude of human pressures, making them highly vulnerable to plant invasions. In fact, in Europe, riparian areas are considered to be among the most vulnerable habitat types. As foci of invasive plant species richness, they play an important role in the process of their spread into nearby terrestrial ecosystems. Various disturbance events, both natural (i.e. floods) and artificial (e.g. hydro-morphological alterations), in addition to a strong propagule pressure these areas are subjected to, increase the invasibility of these vulnerable zones. Given their ecological importance and susceptibility to plant invasions, the preservation and restoration of riparian zones is especially important in light of climate change. In order to preserve and restore the ecosystem services and biodiversity of riparian areas, invasive alien plants have to be managed. The success of restoration measures and control activities can be affected by many variables, such as the invasive plants' residence time and their legacy effects. Furthermore, different environmental factors and drivers of invasion must also be considered, as they could potentially impair the restoration measures. Finally, a successful restoration effort depends on the inclusion of all the relevant stakeholders and their understanding of the importance of preventing and managing plant invasions.

Optimized suspect screening approach for a comprehensive assessment of the impact of best management practices in reducing micropollutants transport in the Potomac River watershed

The vast number of chemicals potentially reaching aquatic environment pose a challenge in maintaining the quality of water resources. However, best management practices to improve water quality are typically focused on reducing nutrient transport without assessing how these practices may impact the occurrence of micropollutants. The potential for co-management of nutrients and organic micropollutants exists, but few studies have comprehensively evaluated the suite of contaminants associated with different water quality management practices (riparian zone restoration, stormwater management, etc.). Furthermore, most studies dealing with the determination of micropollutants in environmental samples include only a limited number of target analytes, leaving many contaminants undetected. To address this limitation, there has been a gradual shift in environmental monitoring from using target analysis to either suspect screening analysis (SSA) or non-targeted analysis (NTA), which relies on accurate mass measurements, mass spectral fragmentation patterns, and retention time information obtained using liquid chromatography coupled to high-resolution mass spectrometry. The work presented in this paper focuses on a wide-scope detection of micropollutants in surface water samples from the Potomac River watershed (United States). An in-house database composed of 1039 compounds based on experimental analysis of primary standards was established, and SSA workflow was optimized and applied to determine the presence of micropollutants in surface water. A total of 103 micropollutants were detected in the samples, some of which are contaminants that were not previously monitored and belong to various classes such as pharmaceuticals, personal care products, per-and polyfluoroalkyl substances and other persistent industrial chemicals. The impact of best management practices being implemented for nitrogen and phosphorus reductions were also assessed for their potential to reduce micropollutant transport. This work illustrates the advantages of suspect screening methods to determine a large number of micropollutants in environmental samples and reveals the potential to co-manage a diverse array of micropollutants based on shared transport and transformation mechanisms in watersheds.

Increases in soil and woody biomass carbon stocks as a result of rangeland riparian restoration

BackgroundGlobally, vegetation in riparian zones is frequently the target of restoration efforts because of its importance in reducing the input of eroded sediment and agricultural nutrient runoff to surface waters. Here we examine the potential of riparian zone restoration to enhance carbon sequestration. We measured soil and woody biomass carbon stocks, as well as soil carbon properties, in a long-term chronosequence of 42 streambank revegetation projects in northern California rangelands, varying in restoration age from 1 to 45 years old.ResultsWhere revegetation was successful, we found that soil carbon measured to 50 cm depth increased at a rate of 0.87 Mg C ha−1 year−1 on the floodplain and 1.12 Mg C ha−1 year−1 on the upper bank landform. Restored sites also exhibited trends toward increased soil carbon permanence, including an increased C:N ratio and lower fulvic acid: humic acid ratio. Tree and shrub carbon in restored sites was modeled to achieve a 50-year maximum of 187.5 Mg C ha−1 in the channel, 279.3 Mg ha−1 in the floodplain, and 238.66 Mg ha−1 on the upper bank. After 20 years of restoration, the value of this carbon at current per-ton C prices would amount to $US 15,000 per km of restored stream.ConclusionWe conclude that revegetating rangeland streambanks for erosion control has a substantial additional benefit of mitigating global climate change, and should be considered in carbon accounting and any associated financial compensation mechanisms.

Greenhouse gas emissions from riparian zone cropland in a tributary bay of the Three Gorges Reservoir, China.

BackgroundA huge reservoir was formed by the Three Gorges Dam in China, which also formed a riparian zone along the bank of the reservoir. In the period of low water-level, the riparian zone in tributary bays of the Three Gorges Reservoir (TGR) was always unordered cultivated, owing to its gentle slope and high soil fertility. This land-use practice creates high potential of generating greenhouse gas (GHG) emissions with periodic water level fluctuation.MethodsTo evaluate potential GHG emissions from the soil-air interface, the static opaque chamber method was adopted to evaluate the effect of elevations (180 m, 175 m, 170 m and 165 m) and land use types (dry lands, paddy fields and grass fields) from April to September in 2015 and 2016.ResultsThe results showed that carbon dioxide (CO2) was the main contributor of GHG emission in riparian zone most likely because of high organic carbon from residues. Furthermore, high soil water content in paddy fields resulted in significantly higher methane (CH4) flux than that in dry lands and grass fields. Compared to grass fields, anthropogenic activities in croplands were attributed with a decrease of soil total carbon and GHG emissions. However, inundation duration of different elevations was found to have no significant effect on CH4 and CO2 emissions in the riparian zone, and the mean nitrous oxide (N2O) flux from dry lands at an elevation of 165 m was significantly higher than that of other elevations likely because of tillage and manure application. The high N2O fluxes produced from tillage and fertilizer suggested that, in order to potentially mitigate GHG emissions from the riparian zone, more attention must be paid to the farming practices in dry lands at low elevations (below 165 m) in the riparian zone. Understanding factors that contribute to GHG emissions will help guide ecological restoration of riparian zones in the TGR.

Multi-dimensional habitat vegetation restoration mode for lake riparian zone, Taihu, China

The riparian zones that were surround bodies of fresh water have been extensively degraded by human influence. Their restoration strength and management are an issue of urgent. Particularly, the knowledge based for the restoration of riparian zone has expanded in recent years. However, progress on a global scale has been limited, because little is known about its complex and diverse functions and structures. A national ecological restoration project of Taihu Lake (China) provided a case study for classifying and restoring the riparian zone. In this work, we quantified the classification of riparian zone, vegetation-zone in the ecotones and a recommended suite of introduced riparian vegetation communities. Taking the structures of the ecotones, soil conditions, vegetation configurations, and anthropogenic disturbances into account, six types of vegetation-zone were used to classify riparian zone, which are as follow: reefs, islands, dokdo–island, island–shore, dike–shore, and shoreland. Then a multi-dimensional habitat vegetation restoration mode for each type based on six vegetation-zones were also recommended. The water ecological quality was developed to a healthy state under this implement. Therefore, results suggest that profound division of habitat-vegetation is important in the modern ecological engineering theories for riparian zone. In order to provide a key parameter for Taihu Lake and other worldwide lakes with similar characteristics, an eco-restoration model and a reconstruction scheme for the vegetation community have been presented. In a conclusion, these recommendations could largely assist further development for lake management.

Soil bioengineering techniques enhance riparian habitat quality and multi-taxonomic diversity in the foothills of the Alps and Jura Mountains

Riparian zones have disproportional ecological importance relative to their size. For decades, the functionality of riparian zones has been altered, with detrimental consequences on biodiversity. Recently, riparian zone restoration has become a major issue. When channel mobility cannot be restored and when erosion control is of primary concern, soil bioengineering techniques are often viewed as a compromise solution. We studied 37 riverbanks, from civil engineering to soil bioengineering, plus natural willow stands, in the foothills of the Alps and Jura Mountains. Using a principal component analysis, we first studied whether terrestrial and aquatic habitat variables varied among riverbank stabilization structures and bank stabilization age and built a synthetic index of riparian habitat quality reflecting the multivariate similarity of riverbank sites. Then, using a modelling approach, we tested whether multi-taxonomic diversity responded to changes in habitat quality and to broad-scale environmental variables (i.e., climate, hydrology and land cover). Soil bioengineering techniques, especially willow fascines and to lower extend vegetated crib wall, enhanced riparian habitat quality by allowing for a greater richness and density of pioneer tree species but also for a larger cover of high quality aquatic micro-habitats. This increase in riparian habitat quality induced an increase in both terrestrial and aquatic species diversity, highlighting the added-value of soil bioengineering techniques to restore riparian biodiversity. This may confirm that stabilization structures made of willow fascines are better suited than stabilization structures made of artificial substrata to support riparian species. Also, beyond the positive effect of soil bioengineering techniques for riparian biodiversity, we found that climatic, hydrological and land cover variables strongly influenced diversity patterns. Thus, multi-taxonomic diversity decreased along larger rivers and in landscapes dominated by urban areas. This may indicate that the full added value of soil bioengineering techniques for biodiversity will only become apparent if more attention is paid to mitigating the negative impact of human activities in the vicinity of riparian zones and if larger scale environmental parameters are taken into account as early as possible in restoration project. Therefore, we strongly recommend that riverbank restoration projects, based on the active introduction of native pioneer tree species, should be planned at the catchment scale.

How maintenance and restoration measures mediate the response of riparian plant functional composition to environmental gradients on channel margins: Insights from a highly degraded large river

Riparian habitats are transitional zones where strong environmental gradients shape community. To prevent flood risks and channel migration on managed rivers, civil engineering techniques have been widely used. Recently, ecological restoration of rivers has become a major issue. However, given the alteration of natural disturbance regimes induced by human infrastructures, the real added-value of these restoration actions is questionable. Thus, a major challenge is to better understand whether changes in abiotic conditions induced by human activity influence the response of plant communities to environmental gradients. Studying a highly degraded large river, we evaluated the effect of the elevation and soil texture gradients on plant functional composition and assessed whether human-mediated environment gradients, achieved through maintenance and restoration measures, shape community structure. In the summer of 2017, we sampled 17 geomorphic surfaces, mostly gravel bars, along the Rhône River and its tributaries that were either repeatedly cleared (brush clearing vs plowing), newly reprofiled or naturally rejuvenated by high flows. The results show shifts in trait values with elevation and convergence in plant traits with increasing proportion of fine sediments. The co-occurrence of species with contrasting traits was higher in highly disturbed environments, revealing the importance of rejuvenation processes. However, the influence of both environmental gradients was mediated by human activity. For maintenance measures, plowing was better able to promote species diversity and limited biotic homogenization along environmental gradients. Among the three geomorphic surfaces, naturally rejuvenated bars were the most stressful environments, hosting distinct functional assemblages, while communities on newly reprofiled banks were in the same ecological trajectories as repeatedly cleared bars. To promote an effective ecological restoration of riparian zones, (i) a greater variability of the minimum flow is needed, (ii) bedload transport restoration should be a priority and (iii) reprofiled banks should better mimic the landforms of natural river margins.

Assessment of Soil Aggradation through Soil Aggregation and Particulate Organic Matter by Riparian Switchgrass Buffers

The restoration of riparian zones has been an important issue in many regions for the recovery of ecosystem functions. The objective of this study was to assess soil aggradation in a 7-year established riparian switchgrass buffer (SGB) and in a non-buffered riparian zone with an annual row crop (ARC). We measured the aggregate size distribution and stability of macroaggregates, aggregate-associated soil organic carbon, soil organic matter fractions and the chemical composition of light particulate organic matter to monitor soil aggregation in a riparian soil following the conversion of agricultural row crops to switchgrass filters. Aggregate size fractions were separated by wet sieving using the aggregate size-stability protocol. The proportion of soil and total organic C was quantified for each aggregate size class. Soil organic matter fractions were isolated by size and density into light particulate organic matter and heavy particulate organic matter and mineral fraction organic matter. The categorization of aggregates by size and water stability (slaking resistance) showed a significantly larger (p < 0.001) proportion of water-unstable large macroaggregates (>2000 µm) under SGB (34%) compared to that under ARC (29%), while the proportion of water-unstable small macroaggregates (250–2000 µm) was significantly higher under ARC (14%) than under SGB (10%). Our results showed that the amounts of light and heavy particulate organic matter did not change in the short-term (7 years) after SGB establishment. It appears that the lower soil stabilization and soil organic C storage under SGB is related to (i) the large number of coarse roots; (ii) lower inputs of light and heavy particulate organic matter; (iii) no changes in the alkyl-C/O-alkyl-C ratio over time; and (iv) light particulate organic matter with a high C/N ratio.

涟江流域不同类型河岸带模拟径流过程及氮流失研究

本研究以涟江流域作为研究对象，采用路线调查法对流域河岸带类型进行调查，根据土地利用方式、植被类型、地形地貌、土壤质地、人类活动强度、植被覆盖度等指标对涟江流域河岸带分类，选取不同类型河岸带运用径流槽模拟地表径流冲刷，测定土壤水分入渗和地表径流中氮流失量，以期能为流域面源污染防治以及良好河岸带结构的构建提供参考。研究表明：草地 + 壤土 + 山地、V型河谷 + 重度干扰类型河岸带地表径流产生量最大，单次冲刷最大地表径流量为757 mL；农业用地 + 水稻田撂荒地 +丘陵、U型沟谷 + 壤土 + 重度人类干扰类型与农业用地 + 坡耕地裸地 + 丘陵、U型沟谷 + 壤土 + 重度人类干扰类型产生量最低，6次冲刷均未产生地表径流。水分入渗量则相反，这三种类型单次冲刷入渗量分别为43 mL、800 mL、800 mL。不同类型河岸带模拟冲刷径流中总氮、铵态氮、硝态氮流失量均随冲刷次数增多而降低，其中硝态氮流失量大于铵态氮流失量。总氮、铵态氮、硝态氮流失量最大为建设用地 + 裸地 + 壤土 + 山地、V型河谷+重度干扰类型河岸带，流失量分别为4.60 mg/L、1.74 mg/L、2.11 mg/L；流失量最小为草地 + 壤土 + 山地、V型河谷 + 重度干扰类型河岸带，流失量分别为1.56 mg/L、0.45 mg/L、0.47 mg/L。本研究从局域尺度揭示了不同河岸带氮流失特征。 A riparian zone is an ecotone between fresh-water ecosystems and terrestrial ecosystems. Understanding of the ecological processes occurring in the riparian zone will provide knowledge for a control of non-point source pollution in a watershed and restoration of riparian zones. Riparian zones along Lianjiang River in central Guizhou province of China were investigated through a route survey method to define the types of the riparian zones in Karst Rivers. According to the utilization of soil, vegetation types, topography, soil texture, the intensity of human activities and vegetation coverage, the types of the riparian zone along Lianjiang River were classified into eight types. Furthermore, Surface runoff, soil water infiltration and loss of nitrogen with the surface runoff were determined at the different sites representing these eight types of the riparian zones using a runoff trough under a condition of the simulation of the surface runoff. The results indicated that the surface runoff from the riparian type “Grass + loam + mountain and V-shaped valley + severe disturbance” is largest in a single or total event of the surface runoff. The surface runoff from both the riparian types “Agricultural land + rice paddies abandoned land + hills, U-shaped valleys + loam + intense human disturbance” and “Agricultural land + slope to bare land + hills, U-shaped valleys + loam + intense disturbance” is lowest, in which six times scouring soils could not generate the surface runoff. However, the water infiltration amount had an opposite result with three infiltration events, 43mL, 800mL and 800mL. The losses of total nitrogen, ammonium nitrogen, nitrate nitrogen from different river riparian zones increased along with a frequency of scouring, in which the losses of the nitrate nitrogen are higher than that of the ammonium nitrogen. The losses of the total nitrogen, ammonium nitrogen and nitrate nitrogen were largest in the riparian type “Construction land + bare land + loam + mountain and V-shaped valley + intense disturbance”, which were respectively 4.60mg/L, 1.74 mg/L and 2.11 mg/L. The losses of the total nitrogen, ammonium nitrogen and nitrate nitrogen were lowest in the riparian type “Grass + loam + mountain, V-shaped valley + intense disturbance”, which were respectively 1.56 mg/L, 0.45 mg/L and 0.47 mg/L. This study revealed the characteristics of nitrogen leaching loss from the different riparian zones.

USE OF MACROINVERTEBRATES FOR ASSESSMENT OF RESTORATION WORKS INFLUENCE ON THE HABITAT IN FLOODPLAIN LAKES

The paper presents a study concerning the influence of the hydraulic and hydrological connectivity among the oxbow lakes and the restoration of riparian-zones have on aging. Interconnectivity oxbow lakes emerge after complex regulating works for the protection of the shores and bottom of the lakes. Research has analyzed the influence of the hydraulic connectivity of three lakes located in northern Poland on the structure of associated bottom invertebrates elements that monitor the conditions in habitats. The structure and functioning of ecosystems in wetlands, including in oxbow lakes, are direct or indirect in connection to fluctuations in water levels during floods or flow pulsations. Hydrological processes cause changes in the chemical composition of the water in oxbow lakes and sediment dispersion due to the exchange between water and sediments. In the lentic habitats (disconnected from the main river), the retention time is longer than in the semi- and lotic oxbow lakes whereas the productivity of the ecosystem is only internal and limited. The use of macrozoobenthos as bioindicators in re-connected oxbow lakes in small river valleys indicates that, on the long-term period (5 years), it does not have as a result the improvement of the environmental conditions of those habitats. This is shown by the monitoring indicators. The main reason seems to be the loss of the full connectivity between the oxbow lakes and the main river channel within 3 to 4 years, having as a result only systems of semilotic oxbow lakes and rivers. This hampers the free exchange of waters between ecosystems, the washing out of nutrients accumulated in sediments, the removal of bottom sediments, as well as the migration of hydrobionts. Therefore, the improvement of the ecological condition of the oxbow lake habitats and the permanence of those changes depend on the possibility of keeping the full hydrological connectivity to the river.

Integrative conservation of riparian zones

Riparian zones are the interface between aquatic and terrestrial systems along inland watercourses. They have a disproportionate ecological role in the landscape considering their narrow extent, which makes them a good example of small natural features (sensu Hunter, 2017-inthisissue). Characteristically, riparian zones increase species richness in the landscape and provide key services to society, such as soil fertility, water purification, and recreation. Despite the recognized importance of riparian zones for ecological, economic and social reasons, and the vast amount of scientific literature exploring measures for their conservation, current management is still failing at enabling a proper ecological functioning of these areas. The best practices for conservation of riparian zones have mostly focused on manipulating biotic and physical components (e.g. renaturalizing flow regimes, improving channel mobility, and controlling invasions of exotic ecosystem engineer species). However, these strategies face important technical, socio-economic, and legal constraints that require a more integrative approach for effective conservation. In this paper we summarize the main problems affecting riparian zones and their current management challenges. Following Hunter et al. (2017-inthisissue), we review novel approaches to conservation of riparian zones, complementary to manipulating processes that reflect contemporary management and policy. These include (1) investing in environmental education for both local people and technical staff, (2) guaranteeing qualitative and long term inventories and monitoring, (3) establishing legislation and solutions to protect riparian zones, (4) framing economic activities in riparian zones under sustainable management, and (5) planning restoration of riparian zones at multiple and hierarchical spatio-temporal scales.

A design of ecological restoration and eco-revetment construction for the riparian zone of Xianghe Segment of China’s Grand Canal

ABSTRACTThe riparian zone is a unique landscape component that represents an ecological transition between aquatic and terrestrial ecosystems. The restoration of riparian zones has become an ecological focus in the realms of both urban development planning and watershed management. This paper applies the concept of landsenses ecology, ecological restoration principles and a range of eco-revetment models in riparian zone restoration for Xianghe Segment of China’s Grand Canal (XSCGC). Based on field trip investigation, the restoration considerations involve the current status quo of the segment’s riparian zone. In addition to the analysis of key flood control areas, the restoration considers the main functions of various landscape components. The riparian zone is divided into five typical sections: the wetland ecological conservation section in the upper reaches, the wetland ecological conservation section in the lower reaches, the riverside leisure and entertainment section in the middle reaches, the restoration and reconstruction section in the middle reaches, and the ecological agricultural section in the lower reaches. Based on the spatial form, human senses and the flood control function of the riparian zone, three typical revetment models are applied, namely original natural revetment, natural revetment, and hybrid revetment. A vegetation plan was proposed for every functional section. The aim of the present study is to provide a reference for the restoration and ecological management of the riparian zone in XSCGC.

Relationship between dynamics of litterfall and riparian plant species in a tropical stream

We investigated the dynamics of organic matter and type of detritus in a riparian zone of the Atlantic Rain Forest domain, and specifically determined the inputs and stock of detritus contributed by plant species, and their relationship to temperature and precipitation. Our hypotheses tested were: (1) the species composition of riparian vegetation influences the amount and type of detritus delivered to a stream in an Atlantic Rain Forest, and (2) the dynamics of litterfall in the riparian zone is influenced by climate factors. The plant community was formed principally by pioneer and early successional species such as Apuleia leiocarpa, Erytrina velutina, Erytrina verna, Eucalyptus torelliana, Ficus glabra, Ficus insipida, Guarea guidonea, Guarea guidonia, Maprounea guianensis and Psidium guajava. There was a large number of G. guidonea (318 individuals/ha), followed by Cupania oblongifolia (91), Trichilia pallida (52), Piptadenia gonoacantha (26) and E. torelliana (14). G. guidonea contributed >50% of the total litterfall; however, some species which were present in high density in the plant community and did not yield significant biomass, indicating that detritus production was based on the contribution of a few species. We found 697, 856 and 804 g/m2/year from vertical, terrestrial, and lateral inputs, respectively, whereas to the annual benthic standing stock was 3257 g/m2. Detritus was formed by leaves (60%), branches (32%), reproductive parts (3%), and unidentifiable fragments of organic-matter (5%). Inputs and benthic stock were markedly seasonal, with an increase of leaf litter during the dry season. Our results indicate that litterfall dynamics is basically composed of a few species that contribute with higher values of biomass. Moreover, ecological characteristics together with environmental factors can be viewed as the principal factors determining the energy balance of riparian ecosystems. The biological implications of the dynamics of organic matter have high importance for the maintenance and restoration of riparian zones. However, the amount of litterfall required to maintain the balance of the riparian community remains unclear in the tropical zone.

A Comparative Study on Nitrogen and Phosphorus Concentration Characteristics of Twelve Riparian Zone Species from Upstream of Hunhe River

On upstream of Hunhe River, the riparian zone and water quality has been impacted by increasing anthropogenic activities. Nitrogen and phosphorus run‐off the river, has led to eutrophication. In this study, total nitrogen (TN) and total phosphorus (TP) concentrations were measured from different tissues (roots, stems and leaves) of twelve plants from the upstream riparian zone of the Hunhe River. The TN concentration ranged between 6.45 and 39.94 mg/g, while the TP range was 2.77–9.20 mg/g. A positive correlation of r2 = 0.5157, p < 0.05 was recorded between N/P ratios and TN. This showed that plants growth was limited by N according to the “law of the minimum”. The concentrations of TN and TP in leaves were significantly higher than that in roots and stems. There were significant differences among life forms (tree, shrub, and herb) with respect to TP and N/P ratios. The data provided a theoretical guidance to plant species screening for the riparian zone restoration in purpose of the water quality improvement in the Hunhe River.

Monitoring and modeling water‐vegetation interactions in groundwater‐dependent ecosystems

In many regions around the world, groundwater is the key source of water for some vegetation species, and its availability and dynamics can define vegetation composition and distribution. In recent years the interaction between groundwater and vegetation has seen a renewed attention because of the impact of groundwater extraction on natural ecosystems' health and increasing interest in the restoration of riparian zones and wetlands. The literature provides studies that approach this problem from very different angles. Information on the vegetation species that are likely to depend on groundwater and the physical characteristics of such species can be found in a large body of literature in ecology and plant physiology. Environmental engineers, hydrologists, and geoscientists are more focused on ecosystem restoration and the estimation of a catchment's water balance, for which the groundwater transpired by vegetation might be an important component. Here we join together these different bodies of literature with the aim of providing the state of knowledge on groundwater‐dependent vegetation. We describe the physiological features that characterize groundwater‐dependent vegetation, review different methods to study vegetation water use in the field, discuss recent advances in the understanding of how groundwater levels might determine vegetation composition, and present a summary of the available mathematical models that include the interaction between groundwater levels and vegetative water use. Several future research directions are identified, such as the quantification and modeling of the partitioning of transpiration between unsaturated and saturated zones and the development of integrated models able to link hydrology, ecology, and geomorphology.

Carbon storage of headwater riparian zones in an agricultural landscape

BackgroundIn agricultural regions, streamside forests have been reduced in age and extent, or removed entirely to maximize arable cropland. Restoring and reforesting such riparian zones to mature forest, particularly along headwater streams (which constitute 90% of stream network length) would both increase carbon storage and improve water quality. Age and management-related cover/condition classes of headwater stream networks can be used to rapidly inventory carbon storage and sequestration potential if carbon storage capacity of conditions classes and their relative distribution on the landscape are known.ResultsBased on the distribution of riparian zone cover/condition classes in sampled headwater reaches, current and potential carbon storage was extrapolated to the remainder of the North Carolina Coastal Plain stream network. Carbon stored in headwater riparian reaches is only about 40% of its potential capacity, based on 242 MgC/ha stored in sampled mature riparian forest (forest > 50 y old). The carbon deficit along 57,700 km headwater Coastal Plain streams is equivalent to about 25TgC in 30-m-wide riparian buffer zones and 50 TgC in 60-m-wide buffer zones.ConclusionsEstimating carbon storage in recognizable age-and cover-related condition classes provides a rapid way to better inventory current carbon storage, estimate storage capacity, and calculate the potential for additional storage. In light of the particular importance of buffer zones in headwater reaches in agricultural landscapes in ameliorating nutrient and sediment input to streams, encouraging the restoration of riparian zones to mature forest along headwater reaches worldwide has the potential to not only improve water quality, but also simultaneously reduce atmospheric CO2.