Restoration Of Riparian Ecosystems Research Articles

Quantifying river water contributions to the transpiration of riparian trees along a losing river: lessons from stable isotopes and an iteration method

Abstract. River water plays a critical role in riparian plant water use and riparian ecosystem restoration along losing rivers (i.e., river water recharging underlying groundwater). How to quantify the contributions of river water to the transpiration of riparian plants under different groundwater levels and the related responses of plant water use efficiency is a great challenge. In this study, observations of stable isotopes of water (δ2H and δ18O), 222Rn, and leaf δ13C were conducted for the deep-rooted riparian weeping willow (Salix babylonica L.) in 2019 (dry year) and 2021 (wet year) along the Chaobai River in Beijing, China. We proposed an iteration method in combination with the MixSIAR model to quantify the river water contribution to the transpiration of riparian S. babylonica and its correlations with the water table depth and leaf δ13C. Our results demonstrated that riparian S. babylonica took up deep water (in the 80–170 cm soil layer and groundwater) by 56.5 % ± 10.8 %. River water recharging riparian deep water was an indirect water source and contributed 20.3 % of water to the transpiration of riparian trees near the losing river. Significantly increasing river water uptake (by 7.0 %) and decreasing leaf δ13C (by −2.0 ‰) of riparian trees were observed as the water table depth changed from 2.7 m in the dry year of 2019 to 1.7 m in the wet year of 2021 (p<0.05). The higher water availability probably promoted stomatal opening and thus increased transpiration water loss, leading to the decreasing leaf δ13C in the wet year compared to the dry year. The river water contribution to the transpiration of riparian S. babylonica was found to be negatively linearly correlated with the water table depth and leaf δ13C (p<0.01). The rising groundwater level may increase the water extraction from the groundwater and/or river and produce a consumptive river-water-use pattern of riparian trees, which can have an adverse impact on the conservation of both river flow and riparian vegetation. This study provides new insights into understanding the mechanisms of the water cycle in a groundwater–soil–plant–atmosphere continuum and managing water resources and riparian afforestation along losing rivers.

Dam inundation duration as a dominant constraint on riparian vegetation recovery

The identification of limiting factors is essential for the ecological restoration of riparian ecosystems degraded by the damming of rivers, but remains unclear. Here, we quantitatively assessed the relative importance of environmental factors and revealed the main limiting factors for riparian vegetation restoration and their influencing mechanisms, using riparian plant and environmental data of seven large reservoirs in southwest China. We found that inundation duration had a significantly greater effect on riparian vegetation distribution, cover and diversity than environmental factors such as inundation depth, rainfall, humidity, temperature, sunshine hours, aspect, slope, surface relief, soil pH, available nitrogen (AN), available phosphorus (AP), and available potassium (AK); vegetation cover, species richness, complexity and dominance were highly significantly negatively correlated with inundation duration (p < 0.01); inundation for 5 months is close to the tolerance limit of most plants and poses a significant limiting effect on the vegetation restoration in the reservoir riparian. Therefore, the inundation duration should be highlighted in riparian vegetation restoration. Meanwhile, incorporating the riparian inundation into the river ecological scheduling objectives to shorten the inundation duration and thus radically alleviate the limitation is a new opportunity for vegetation restoration in the reservoir riparian.

Response of two riparian woody plants to Phytophthora species and drought

Disease combined with drought poses an important threat to plant survival, often compromising success in the restoration of riparian forests. Thus, understanding how biotic and abiotic stressors may affect plant survival and growth performance can greatly increase the success of ecosystem management strategies. The purpose of this study was to understand how two plant species, often used together in restoration of riparian ecosystems but with different ecological preferences, would respond to infection by each of two Phytophthora species in Mediterranean-climate regions, in the absence or presence of a simulated drought. Saplings of the drought resistant species Frangula californica, and of the riparian species Alnus rhombifolia were each inoculated in a greenhouse experiment with one of two Phytophthora species and exposed to two watering regimes. Saplings were allocated to six treatments, combining three levels of pathogen inoculation (no inoculation, inoculation with Phytophthora cactorum and inoculation with Phytophthora crassamura), and two watering regimes (well-watered and drought). The response of A. rhombifolia and F. californica saplings was assessed through the observation of health metrics and morphological parameters. Results showed that both P. cactorum and P. crassamura are important pathogens of A. rhombifolia and F. californica. As expected, drought conditions were the main cause of decline and mortality in A. rhombifolia saplings, while water availability was a facilitator of P. cactorum infection in F. californica saplings. We observed two seemingly contrasting results in A. rhombifolia saplings: infection by Phytophthora spp. decreased survival in well-watered plants, while the opposite was recorded for saplings under drought conditions whose survival increased in Phytophthora-inoculated treatments. Saplings of F. californica were able to cope with drought conditions, even when infected by Phytophthora species and water availability increased root infection and decreased sapling survival. We conclude that the continued use of F. californica and A. rhombifolia in sites infested by Phytophthora species can be beneficial in restoration, if appropriate management actions are adopted. Such actions include avoiding the planting of F. californica saplings in areas subjected to water accumulation, and ensuring that A. rhombifolia is planted in areas where drought stress is minimal and where Phytophthora species are possibly absent. We also emphasize the importance of ensuring that plant stock used in revegetation projects is not infected by Phytophthora species, and that biotic and abiotic risks are assessed prior to restoration actions.

The Conservation and Restoration of Riparian Forests along Caribbean Riverbanks Using Legume Trees

In the actual context of global change and biodiversity depletion, soil bioengineering represents an important tool for riparian ecosystem restoration and species conservation. Various techniques have already been implemented, but their adaptation still must be carried out in Caribbean Islands biodiversity hotspots, where suitable species remains unknown. Nitrogen-fixing legumes are particularly relevant for ecological restoration and the diversity of native Caribbean legume trees is promising in the search for suitable species for soil bioengineering. We hypothesized that Caribbean legume tree species present a growth performance and set of biotechnical traits compatible with their use in soil bioengineering. We selected five native legume trees, adapted to riparian environments, in different ecosystems (swamp forest, evergreen seasonal forest, rainforest) based on their ecology, resistance to disturbance and seed production characteristics. We measured root traits relevant for soil bioengineering on nursery grown 3-month-old seedlings. Despite their differences in sensitivity to herbivory and in growth strategies, the selected species have a high potential for use in soil bioengineering, with high seed production, high germination rates—from 88 to 100%—, and 100% survival rates, and are therefore compatible with large scale plant material production. We provided practical guidance tools for their integration into soil bioengineering techniques.

Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA.

Riparian ecosystem restoration has been accomplished through exclusion of livestock using corridor fencing along hundreds of kilometers of streams in the western United States, for the benefit of riparian-obligate wildlife and endangered fishes. Yet, there are limited scientific studies that have evaluated more than short-term shifts in vegetation composition and diversity at a single location or handful of locations following grazing. We sampled riparian vegetation composition along 11-paired grazed and ungrazed (exclosed) stream reaches in northeastern Oregon. Exclosure ages ranged from 2 to >30 years and grazing treatments varied from light grazing every one out of three years to heavy season-long grazing. Species richness and diversity was higher in the ungrazed reaches (p = 0.002). The abundance of native sedges (Carex spp.) and broad-leaved forbs were also significantly (p ≤ 0.05) greater in ungrazed areas. In contrast, exotic species adapted to grazing such as Poa pratensis and Trifolium repens were more abundant in grazed stream reaches. The prevalence of hydrophytic species significantly increased (p ≤ 0.01) in ungrazed reaches, (based on wetland species indicator scores), indicating that wetland-dominated communities within the ungrazed stream reaches were replacing ones adapted to drier environments. The increased abundance of facultative and wetland-obligate species in ungrazed reaches compared to grazed reaches suggests that livestock grazing exacerbates those climate change effects also leading to warmer and drier conditions. Further, riparian-obligate shrub cover along the streambank was higher in 7 of 8 exclosures that were older than 5 years (p = 0.05). As a restoration approach, the inherent resilience of riparian ecosystems exhibited in ungrazed riparian zones suggest positive feedbacks to other beneficial ecosystem processes such as increased species and habitat diversity, increased carbon sequestration, enhanced allochthonous inputs and greater sediment retention, that would affect the aquatic and terrestrial biota, water quality, and stream morphology.

Guiding restoration of riparian ecosystems degraded by plant invasions: Insights from a complex social-ecological system in the Global South.

Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01691-y.

Does soil bioengineering benefits aquatic biodiversity? An empirical study of the relative influence of local and regional drivers on benthic macroinvertebrate assemblages

Riverine ecosystems form a dendritic network in which landscape and catchment-scale properties influence freshwater community structure. Placed in a restoration framework, this suggests that regional drivers can overrule the benefit of measures aiming at improving local habitat quality. Disentangling the relative influence of local and regional drivers on freshwater communities is thus crucial for ecosystem management and restoration. Along riverbanks, soil bioengineering is often used to both control erosion and improve ecological conditions. Soil bioengineering techniques aim at copying naturally functioning riverbank models and can thus be viewed as riparian ecosystem restoration. Nevertheless, these techniques are mostly designed at the local scale and are implemented in a broad range of rivers. This implies large variations in regional drivers, which may greatly influence the response of freshwater communities to restoration efforts. We studied 37 riverbanks, from civil engineering to soil bioengineering, plus natural willow stands, in the foothills of the Alps and Jura Mountains, and assessed the relative influence of local (terrestrial and aquatic habitat conditions) and regional (water quality, hydrological context and land cover composition) drivers on benthic macroinvertebrate assemblages. Using multivariate GLM and structural equation modelling, we investigated variations in the taxonomic and functional composition and in the diversity of native, exotic, shredder and scraper taxa to both set of drivers. Our results showed that soil bioengineering improved local habitat conditions, with an increase in the vegetation density and in the aquatic habitat quality. These changes directly influenced functional composition but indirectly diversity patterns. Instead, we found that native and shredder species richness increased between civil engineered and soil bioengineered structures, suggesting a positive effect of vegetated riverbanks on other local abiotic factors (i.e. shade, water temperature, organic matter supply). Our results also showed that macroinvertebrates were more influenced by regional than by local drivers. Thus, the hydrological context best explained the composition of taxa feeding habits and variation in taxa diversity, with larger abundance and richness of scrapers and shredders in small headwater streams. Land cover ranked second in explaining variation in functional composition. Also, the diversity of natives, scrapers and shredders increased as the proportion of predominantly urban landscapes decreased. Finally, the abundance of scraper and native species increased with water quality, while the richness of exotic species decreased. Overall, these results highlight the hierarchical structure of local and regional drivers on freshwater communities. Along river networks, catchment-scale properties and landscape attributes are major drivers of macroinvertebrate assemblages. Soil bioengineering improves habitat quality and as such appears to be a good compromise solution to control erosion and support freshwater communities, even though this nature-based solution cannot solve anthropogenic pressures at larger scales. To improve the efficiency of restoration efforts, integrated approaches accounting for both local and regional drivers remains a priority.

Disentangling the effects of edaphic and vegetational properties on soil aggregate stability in riparian zones along a gradient of flooding stress

Riparian zone is an ecotone between aquatic and terrestrial ecosystems, where soil aggregate stability is fundamental in supporting ecosystem functions and associated services. Yet, little is known about the resilience of riparian soil aggregate stability along a gradient of flooding stress. Here, we studied a riparian ecosystem across hillslopes in an early successional stage (a grass-dominated successional stage) along a gradient of flooding intensity (FI) of a hydrological regime triggered by operation of the Three Gorges Dam (TGD), China, which is one of the biggest dams in the world. Size distribution and stability of soil aggregates were tested by the wet-sieving method. Path analysis and structural equation modelling (SEM) were applied to determine the contributions of abiotic and biotic factors (including environmental variables, soil physicochemical properties, vegetational properties) to soil aggregate stability. Results showed that soil aggregate stability decreased with FI (a ratio of flooded days to whole days) which was a major determinant of soil aggregation. Also, increasing soil water content (SWC) greatly contributed to the decrease of aggregate stability, while contents of soil organic matter and total nitrogen correlated with an increase of aggregate stability. In terms of vegetational properties, aboveground biomass, plant species richness, and plant functional types partially explained soil aggregation. Significantly, distribution of the riparian dominant pioneer species, Cynodon dactylon, was affected by FI and SWC, and a higher density of the species led to a lower amount of small macro-aggregates (0.25–2 mm). Our study reveals that the soil stabilizing process is mainly governed by FI and edaphic factors, although vegetational properties have potentials to influence the soil aggregate stability. Our study highlights the vital processes for ecological restoration of riparian ecosystem in an early successional stage under a drastic change in hydrological regime.

Restoring degraded riparian forest ecosystems of the Western Ghats for ecological sustainability

The riparian ecosystems of the Western Ghats are highly diversified tropical forest ecosystems. The synergic effect of various threats may adversely affect and reduce the capacity of these riparian ecosystems to resilience, even though they have specific adaptations for living in extreme conditions. These diversity‐rich riparian ecosystems provide critical ecological services such as influencing environmental processes, acting as habitats for both terrestrial and aquatic biota, and supporting the livelihood of the surrounding community. Hence the restoration of such damaged ecosystems is highly significant. This article presents a scheme for sustainable restoration of the disturbed riparian ecosystems with the involvement of multi‐stakeholders. The three‐stage scheme ensures the support and livelihood of the local community, along with the ecological restoration of riparian ecosystems using nature‐based solutions with a scientific approach. The restoration will enhance the ecosystem services, climate change adaptations, and resilience, as well as the carbon sequestration capacity of the tropical region.

Managing Oil Palm Plantations More Sustainably: Large-Scale Experiments Within the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme

Conversion of tropical forest to agriculture results in reduced habitat heterogeneity, and associated declines in biodiversity and ecosystem functions. Management strategies to increase biodiversity in agricultural landscapes have therefore often focused on increasing habitat complexity; however, the large-scale, long-term ecological experiments that are needed to test the effects of these strategies are rare in tropical systems. Oil palm (Elaeis guineensis Jacq.)—one of the most widespread and important tropical crops—offers substantial potential for developing wildlife-friendly management strategies because of its long rotation cycles and tree-like structure. Although there is awareness of the need to increase sustainability, practical options for how best to manage oil palm plantations, for benefits to both the environment and crop productivity, have received little research attention. In this paper we introduce the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme: a long-term research collaboration between academia and industry in Sumatra, Indonesia. The BEFTA Programme aims to better understand the oil palm agroecosystem and test sustainability strategies. We hypothesise that adjustments to oil palm management could increase structural complexity, stabilise microclimate, and reduce reliance on chemical inputs, thereby helping to improve levels of biodiversity and ecosystem functions. The Programme has established four major components: (1) assessing variability within the plantation under business-as-usual conditions; (2) the BEFTA Understory Vegetation Project, which tests the effects of varying herbicide regimes; (3) the Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project, which tests strategies for restoring riparian habitat; and (4) support for additional collaborative projects within the Programme landscape. Across all projects, we are measuring environmental conditions, biodiversity, and ecosystem functions. We also measure oil palm yield and production costs, in order to assess whether suggested sustainability strategies are feasible from an agronomic perspective. Early results show that oil palm plantation habitat is more variable than might be expected from a monoculture crop, and that everyday vegetation management decisions have significant impacts on habitat structure. The BEFTA Programme highlights the value of large-scale collaborative projects for understanding tropical agricultural systems, and offers a highly valuable experimental set-up for improving our understanding of practices to manage oil palm more sustainably.

Evaluation on Soil Hardness in Riparian Forest Restoration along Kayan Ulu River, Sarawak, Malaysia

Soil hardness plays a vital role in evaluating the physical properties of soil structure. With regards to the impact of compaction on practical forest management issues, most report and review forms were available. Thus, the aim of this study was to evaluate the soil condition in riparian forest restoration planted with indigenous species along Kayan Ulu River with special reference to soil hardness. Soil hardness was measured by using Hasegawa-type cone penetrometer from the surface soils to 100 cm depth, with a total of 48 random points for both study sites surveyed; restoration sites planted with Shorea macrophylla in year 1996 and 1998 (SPD96 and SPD98, respectively) for both on and between planting lines. Our findings indicated that, soil hardness in SPD98 was harder as compared to SPD96 at shallow depth presented in one drop penetrability. Likewise, soil penetration resistance on planting line in SPD98 was significantly higher than SPD96 at surface soils (0-20 cm) and subsurface soils (20-40 cm). A high number of strikes and soil penetration resistance indicate that the soils were highly compacted. However, there was no significant difference in term of soil penetration resistance between planting line. In order to avoid effects on tree productivity, it is recommended that in future, the evaluation of soil hardness should be determined during the early establishment for future restoration of riparian ecosystem. &#x0D; Keywords: Riparian forest restoration, riparian ecosystem, Sarawak, soil hardness

Effects of Soil Compaction and Relative Light Intensity on Survival and Growth Performance of Planted Shorea macrophylla (de Vriese) in Riparian Forest along Kayan Ulu River, Sarawak, Malaysia

A study was conducted in riparian forest along Kayan Ulu River, Sarawak, Malaysia, to investigate the effects of soil compaction and relative light intensity (RLI) on survival and growth performance of planted Shorea macrophylla. The study sites were stands reforested in different years (1996: SPD96; 1997: SPD97; 1998: SPD98; 1999: SPD99). The survival, growth performance, soil compaction, and RLI were measured. SPD96 trees had the highest survival (84%) and showed the most favourable growth. Average height, mean annual increment in height, and RLI were highest in SPD97 while mean annual increment in volume was highest in SPD98. Soil compaction in SPD98 and SPD99 was higher as compared to SPD96 and SPD97. This was due to the compacted soils caused by anthropogenic activities and natural causes (wet soils) in riparian forest along Kayan Ulu River at shallow depth. High survival and favourable growth performance of S. macrophylla were influenced by the edaphic factor with special reference to less compacted soils and high RLI. Stepwise multiple regression demonstrated significant effects of soil penetration resistance at the depth of 0-30 cm and RLI on mean annual increment in diameter. Further ecological studies on other environmental factors should be implemented to draw up a Dipterocarp planting scheme for the future restoration of riparian ecosystem.

Bosques ribereños del trópico húmedo de México: un caso de estudio y aspectos críticos para una restauración exitosa

Los bosques ribereños albergan una biodiversidad importante y en ellos se desarrollan funciones ecológicas esenciales que repercuten en la provisión de servicios ecosistémicos relevantes para la sociedad. Las perturbaciones de origen antrópico frecuentemente exceden la resiliencia natural de estos ecosistemas y, en consecuencia, desencadenan procesos de degradación. La restauración ecológica busca recuperar la biodiversidad y los servicios de los bosques ribereños, pero su éxito depende de varios aspectos de contexto. En este trabajo se utiliza un estudio de caso para ejemplificar la problemática de la restauración desde una perspectiva ‘integral’ y se discuten aspectos ecológicos, socio-económicos y legales que pueden influir en el éxito de la restauración de estos bosques. Si bien los aspectos ecológicos han sido considerablemente desarrollados, aún falta información relacionada con las limitaciones económicas (p. ej. los costos de producción), sociales (p. ej. la aceptación social) y legales (p.ej. la incorporación de la restauración ecológica en programas públicos), para ser aplicados a escalas más amplias. La estimación de los servicios ecosistémicos que podrían restablecerse a partir de la restauración de bosques ribereños aportará a la integración de estos aspectos. El abordaje de estos aspectos a escala local aportará información para el desarrollo futuro de estrategias a escala regional más eficientes en términos de la relación beneficio ecológico–costo socioeconómico. Se discuten algunas recomendaciones relacionadas con la conservación, el manejo y la restauración de los bosques ribereños en el trópico húmedo de México.

Effects of dams and geomorphic context on riparian forests of the Elwha River, Washington

AbstractUnderstanding how dams affect the shifting habitat mosaic of river bottomlands is key for protecting the many ecological functions and related goods and services that riparian forests provide and for informing approaches to riparian ecosystem restoration. We examined the downstream effects of two large dams on patterns of forest composition, structure, and dynamics within different geomorphic contexts and compared them to upstream reference conditions along the Elwha River, Washington, USA. Patterns of riparian vegetation in river segments downstream of the dams were driven largely by channel and bottomland geomorphic responses to a dramatically reduced sediment supply. The river segment upstream of both dams was the most geomorphically dynamic, whereas the segment between the dams was the least dynamic due to substantial channel armoring, and the segment downstream of both dams was intermediate due to some local sediment supply. These geomorphic differences were linked to altered characteristics of the shifting habitat mosaic, including older forest age structure and fewer young Populus balsamifera subsp. trichocarpa stands in the relatively static segment between the dams compared to more extensive early‐successional forests (dominated by Alnus rubra and Salix spp.) and pioneer seedling recruitment upstream of the dams. Species composition of later‐successional forest communities varied among river segments as well, with greater Pseudotsuga menziesii and Tsuga heterophylla abundance upstream of both dams, Acer spp. abundance between the dams, and P. balsamifera subsp. trichocarpa and Thuja plicata abundance below both dams. Riparian forest responses to the recent removal of the two dams on the Elwha River will depend largely on channel and geomorphic adjustments to the release, transport, and deposition of the large volume of sediment formerly stored in the reservoirs, together with changes in large wood dynamics.

Effects of flooding on the seed bank and soil properties in a conservation area on the Han River, South Korea

Flooding can have a major impact on riverside plant communities, and this is likely to be especially important in monsoonal climates, where large floods occur after heavy rain. In urban areas where riparian vegetation remnants are the only vegetation of conservation interest remaining, understanding the impacts that floods have on these ecosystems is needed to inform their future conservation. Accordingly, we assessed the impact of a flood caused by Typhoon “Ewiniar” on the soil seed bank of five plant communities of the only remaining fragment of high-quality riverine habitat within the Seoul city stretch of the Han River (South Korea). We surveyed the seed bank composition of the five dominant plant communities before and after the flood. We also measured selected soil physico-chemical properties in each community. We used univariate and multivariate methods to examine the effect of the flood on both seed bank and soil physico-chemical properties. Flooding resulted in variable deposition of sediment within the plant communities; four communities varied from 14.6 to 18.8cm but the fifth (dominated by Miscanthus sacchariflorus) had much less sediment (4.8cm). The physico-chemical properties of the surface soil also changed after the flood, with the sediment particle size being the most affected. The species richness and composition of the seed bank suffered significant changes after the flood. In both cases there was a homogenization process, with was also impinged on species with different life-forms (annuals and perennials). Our results suggest that an extreme flood can affect the riparian vegetation seed bank by removing wetland plant species and allowing common and ruderal species to establish. There may also be different interactions between the different plant communities in terms of sediment capture and this translates into altered soil conditions and seed banks. These results are of use to conservation policy-makers aiming to conserve a native flora within severely modified urban rivers, and these remnant areas can provide an important seed source of wetland plants to aid restoration of riparian ecosystems.

Impact of perceived importance of ecosystem services and stated financial constraints on willingness to pay for riparian meadow restoration in Flanders (Belgium).

The strategic importance of ecosystem service valuation as an operational basis for policy decisions on natural restoration has been increasingly recognized in order to align the provision of ecosystem services with the expectation of human society. The contingent valuation method (CVM) is widely used to quantify various ecosystem services. However, two areas of concern arise: (1) whether people value specific functional ecosystem services and overlook some intrinsic aspects of natural restoration, and (2) whether people understand the temporal dimension of ecosystem services and payment schedules given in the contingent scenarios. Using a peri-urban riparian meadow restoration project in Flanders, Belgium as a case, we explored the impacts of residents' perceived importance of various ecosystem services and stated financial constraints on their willingness-to-pay for the proposed restoration project employing the CVM. The results indicated that people tended to value all the benefits of riparian ecosystem restoration concurrently, although they accorded different importances to each individual category of ecosystem services. A longer payment scheme can help the respondents to think more about the flow of ecosystem services into future generations. A weak temporal embedding effect can be detected, which might be attributed to respondents' concern about current financial constraints, rather than financial bindings associated with their income and perceived future financial constraints. This demonstrates the multidimensionality of respondents' financial concerns in CV. This study sheds light on refining future CV studies, especially with regard to public expectation of ecosystem services and the temporal dimension of ecosystem services and payment schedules.

Stream hydrology limits recovery of riparian ecosystems after wolf reintroduction

Efforts to restore ecosystems often focus on reintroducing apex predators to re-establish coevolved relationships among predators, herbivores and plants. The preponderance of evidence for indirect effects of predators on terrestrial plant communities comes from ecosystems where predators have been removed. Far less is known about the consequences of their restoration. The effects of removal and restoration are unlikely to be symmetrical because removing predators can create feedbacks that reinforce the effects of predator loss. Observational studies have suggested that the reintroduction of wolves to Yellowstone National Park initiated dramatic restoration of riparian ecosystems by releasing willows from excessive browsing by elk. Here, we present results from a decade-long experiment in Yellowstone showing that moderating browsing alone was not sufficient to restore riparian zones along small streams. Instead, restoration of willow communities depended on removing browsing and restoring hydrological conditions that prevailed before the removal of wolves. The 70-year absence of predators from the ecosystem changed the disturbance regime in a way that was not reversed by predator reintroduction. We conclude that predator restoration may not quickly repair effects of predator removal in ecosystems.

Using reference conditions in ecosystem restoration: an example for riparian conifer forests in the Pacific Northwest

Quantifying the attributes of reference sites is a crucial problem in the restoration of ecosystems, driving both the evaluation of current conditions and the setting of management targets for specific points in the future. Restoration of riparian ecosystems, particularly those dominated by conifers, has become a priority because of the numerous ecosystem services they provide, including a high number of vertebrate species in population decline that utilize these structurally complex forests. By way of example, we illustrate a three‐step process to assess the effects of proposed riparian ecosystem restoration efforts: (1) identify reference sites (2) quantify metrics that describe the reference sites, and (3) use models to predict the likely effects of restoration actions relative to reference conditions. To this end, we identified 117 natural, late‐successional conifer dominated stands from existing forest inventories in the Pacific Northwest for the purpose of establishing reference conditions. We did this to establish quantitative metrics for structural attributes essential to the maintenance of biodiversity in these forests, and to assess whether there were any important quantitative differences between upland and riparian forests or whether upland and riparian forest reference sites could be used interchangeably. Both forest types were generally similar, but riparian stands had higher average live tree wood volumes and basal areas, suggesting they may be growing on sites that are more productive. Both riparian and upland forests had abundant large diameter (&gt;50 cm) live trees and snags. Collectively, our data suggest that mature, late‐successional conifer dominated forests have well developed structural characteristics in terms of abundant large trees in the overstory, abundant large snags, and a well‐developed understory of shade‐tolerant trees. We modeled the growth of young conifer stands to assess whether a common restoration treatment would accelerate development of structural characteristics typical of reference conditions. We found that left untreated, the stands followed a trajectory towards developing forest structure similar to the average reference condition. In contrast, the restoration treatment followed a developmental trajectory along the outside range of reference conditions.

Conservação e recuperação da vegetação ripária na perspectiva de pequenos agricultores

Much of the riparian formations in southern Brazil was eliminated, and those that remain are degraded and fragmented. Aiming to verify the viewpoint of the farms of small portions of land for preservation and restoration of riparian ecosystem and as such position may interfere with the conservation and recovery of the same, interviews were conducted with a group of small farmers occupying watershed stream Ajuricaba in the municipality of Marechal Cândido Rondon - PR. We performed an informal approach with the aid of a script of open questions, seeking to characterize the socioeconomic profile of respondents and outline the concepts and opinions forward the conservation and restoration of riparian vegetation. The results were analyzed according to quantitative and qualitative approaches. Farmers interviewed are willing to restore riparian vegetation to their property, but for that to happen they need an incentive, this may be financial, manpower or equipment needed.

Trajectories of change: riparian vegetation and soil conditions following livestock removal and replanting

AbstractRiparian zones provide critically important ecological functions, including the interception of nutrients and sediments before they enter waterways. Consequently, riparian zones, and the vegetation they support, are often considered as an important ‘final buffer’ between waterways and adjacent land. In agricultural ecosystems, riparian zones are therefore increasingly recognized as an important component of strategies aimed at minimizing the flow of nutrients and sediments into waterways. Accordingly, riparian zones are increasingly afforded protection and are targeted for restoration. Here we present results of a study in which we aimed to identify patterns of change in soil and vegetation properties in riparian zones, under different management regimes, adjacent to tributary streams in one of south‐eastern Australia's main agricultural regions. We compared riparia that were heavily impacted by agricultural activities, were in remnant condition or had undergone some restoration activities and were thus in a transitional state. There was an increase in plant cover and soil C concentration between impacted through to remnant sites, with transitional sites intermediate, suggesting that improvements in soil conditions were becoming evident following restoration activities. In our assessment of soil physicochemical properties we investigated the relationships between riparian condition and soil properties, taking into account the influence of adjacent land use on these relationships. Importantly, the concentrations of NO3‐ and plant available P in riparian surface soils were more or less influenced by concentrations in the adjacent land depending upon riparian condition. This will, in turn, have consequences for nutrient inputs into streams. This study emphasizes that riparian zones need to be managed within their wider landscape context. Furthermore, the results of this study will inform efforts seeking to minimize impacts of agricultural activities on waterways, through the conservation and/or restoration of riparian ecosystems.