Assessing leaf physiological traits in response to flooding among dominant riparian herbs along the Three Gorges Dam in China.

Dams worldwide have significantly altered the composition of riparian forests. However, research on the functional traits of dominant herbs experiencing flooding stress due to dam impoundment remains limited. Given the high plasticity of leaf traits and their susceptibility to environmental influences, this study focuses on riparian herbs along the Three Gorges Hydro-Fluctuation Zone (TGHFZ). Specifically, it investigates how six leaf physiological traits of leading herbs-carbon, nitrogen, phosphorus, and their stoichiometric ratios-adapt to periodic flooding in the TGHFZ using cluster analysis, one-way analysis of variance (ANOVA), multiple comparisons, Pearson correlation analysis, and principal component analysis (PCA). We categorized 25 dominant herb species into three plant functional types (PFTs), noting that species from the same family tended to fall into the same PFT. Notably, leaf carbon content (LCC) exhibited no significant differences across various PFTs or altitudes. Within riparian forests, different PFTs employ distinct adaptation strategies: PFT-I herbs invest in structural components to enhance stress resistance; PFT-II, mostly comprising gramineous plants, responds to prolonged flooding by rapid growth above the water; and PFT-III, encompassing nearly all Compositae and annual plants, responds to prolonged flooding with vigorous rhizome growth and seed production. Soil water content (SWC) emerges as the primary environmental factor influencing dominant herb growth in the TGHFZ. By studying the response of leaf physiological traits in dominant plants to artificial flooding, we intend to reveal the survival mechanisms of plants under adverse conditions and lay the foundation for vegetation restoration in the TGHFZ.

Riparian woody plant communities in the Romanian Carpathians: Species diversity and community structure of Salix and Hippophaë communities.

Riparian woody plant communities, including shrubs and trees, are essential for maintaining biodiversity, protecting against floods, reducing erosion, and transporting nutrients. However, these habitats are greatly threatened by human activities, particularly agricultural land acquisition, and the introduction of invasive species. This study examined species diversity and interspecific association in riparian woody plant communities along rivers in the Romanian Carpathians. The study focused on communities of Salix purpurea, S. alba, and Hippophaë rhamnoides in mountain regions, with varying sampling efforts at different sites for each species. A total of 174 plant species were found, predominantly herbaceous (77.9%), followed by trees (11.6%) and shrubs (10.5%). While S. alba and S. purpurea communities show high species richness and abundance, S. alba has slightly higher diversity (H' ≈ 2.23, SD = 0.28) than S. purpurea (H' ≈ 1.69, SD = 0.42). Contrarily, significant differences exist between H. rhamnoides and S. alba communities in species richness (p = .007) and Shannon diversity (p = .004). PCA analysis elaborated on distinct distribution patterns of plant associations within habitats S. purpurea community, H. rhamnoides community, and S. alba community. Four invasive species (Oenothera biennis L. and Oxalis stricta L. in S. alba communities, Reynoutria sachalinensis Nakai in both S. purpurea and H. rhamnoides communities, and Erigeron canadensis L. in H. rhamnoides communities) were identified, as requiring conservation efforts. Hemicryptophytes dominate species richness, while microphanerophytes and megaphanerophytes significantly contribute to plant abundance. H. rhamnoides formed Hippophaë rhamnoides dunes (2160) Natura 2000 habitat, while S. alba created galleries within the 92A0 Salix alba and Populus alba habitat. In conclusion, the findings from this study highlight the importance of preserving riparian habitats because their value goes beyond local or regional considerations and extends to the global scale due to their unique characteristics.

Developing plant functional groups to identify changes in functional composition and diversity in a dryland river experiencing artificially sustained flows.

Land use and climate changes are driving significant shifts in the magnitude and persistence of dryland stream surface flows. The impact of these shifts on ecological functioning is largely unknown, particularly where streams have become wetter rather than drier. This study investigated relationships between hydrologic regime (including surface water persistence, differences in groundwater depth and altered flooding dynamics) with plant traits and riverine vegetation functional composition. Our study system was a previously ephemeral creek in semi-arid northwest Australia that has received groundwater discharge from nearby mining operations for >15 years; surface flows are now persistent for ∼27 km downstream of the discharge point. We aimed to (i) identify plant functional groups (FGs) associated with the creek and adjacent floodplain; and (ii) assess their distribution across hydrological gradients to predict shifts in ecological functioning in response to changing flow regimes. Seven FGs were identified using hierarchical clustering of 40 woody perennial plant species based on morphometric, phenological and physiologic traits. We then investigated how FG abundance (projective foliar cover), functional composition, and functional and taxonomic richness varied along a 14 km gradient from persistent to ephemeral flows, varying groundwater depths, and distances from the stream channel. Dominant FGs were (i) drought avoidant mesic trees that are fluvial stress tolerant, or (ii) drought tolerant xeric tall shrubs that are fluvial stress intolerant. The drought avoidant mesic tree FG was associated with shallow groundwater but exhibited lower cover in riparian areas closer to the discharge (persistent surface flows). However, there were more FGs and higher species richness closer to the discharge point, particularly on the floodplain. Our findings demonstrate that quantifying FG distribution and diversity is a significant step in both assessing the impacts of mine water discharge on riverine ecosystems and for planning for post-mining restoration.

Spatial accumulation of flood-driven riverside litter in two Northern Atlantic Rivers.

The escalation of litter accumulation in aquatic environments is recognized as an emerging global concern. Although rivers represent the main conduits for land-based waste into the oceans, the spatial dynamics of litter accumulation in these systems remain poorly investigated, especially after hydro-climatic extreme events. Floods have been identified as major drivers of litter mobilization, including macroplastics, within rivers. However, predicting flood-induced litter accumulation along riverbanks is complex due to the cumulative interplay of multiple environmental (geomorphological and riparian) and anthropogenic factors. Using empirical data collected from 14 stream reaches in two Northern Atlantic rivers in Portugal, our study evaluates which factors, among geomorphological, riparian, and anthropogenic descriptors, best drive riverside litter accumulation after floods. Taking into account the longitudinal gradient and the spatial heterogeneity of the studied reaches, our study enhances how the accumulation and characteristics (type, size) of riverside litter vary across a rural-urban continuum. Our model reveals that the combination of the human population density and the stream slope at river reach showed the highest explanatory power for the accumulation of riverside litter. Our findings indicate that litter tends to be retained close to the source, even under flood conditions. We also found that the structure of riparian vegetation showed low explanatory power for litter accumulation. However, riparian trapping could be influenced by litter input (density and type) which varies with anthropogenic activities. This work highlights the importance of gathering field data to identify critical areas of riverside litter accumulation within river basins. Our findings can further support environmental managers in designing and implementing effective cleanup campaigns and implementing plastic recovery strategies at specific areas. Nevertheless, it is crucial to enhance coordinated efforts across the entire value chain to reduce plastic pollution, promote innovative approaches for plastic litter valorization, and establish effective prevention pathways.

A large flood resets riverine morphology, improves connectivity and enhances habitats of a regulated river.

Flow regulation in gravel-bed rivers impacts the hydrology, sediments and morphology, riparian vegetation, and vertical connectivity with the hyporheic zone. In this context, previous works have suggested that flood events may have riverine morphological and ecological benefits. In a Mediterranean-climate river system, we analyzed the impact of a 18-year return period flood on river morphology, riparian vegetation, fish aquatic habitat quality, and hyporheic exchange in a dam-regulated gravel-bed river, Serpis River (Spain). We collected pre- and post-flood riparian vegetation distributions and bathymetries, which were used to develop two-dimensional surface and three-dimensional subsurface numerical models to map surface and hyporheic hydraulics. Results show that the large flood removed the invasive giant reed from large areas, reshaped the in-channel morphology by forming new bars and pools, and enhanced the complexity of the flow field and the hydro-morphological diversity. The habitat availability for the endemic Eastern Iberian chub (Squalius valentinus) and invasive bleak (Alburnus alburnus) increased. Hyporheic exchange showed limited change under losing conditions, but noticeable under neutral ambient groundwater condition. This study corroborates the beneficial effects that flood events or high flow releases may have on regulated streams and the potential use of high flow pulse as a restoration tool.

More Than a Service: Values of Rivers, Wetlands and Floodplains Are Informed by Both Function and Feeling.

How people value rivers, wetlands and floodplains influences their attitudes, beliefs and behaviours towards these ecosystems, and can shape policy and management interventions. Better understanding why people value rivers, wetlands and floodplains and their key ecosystem components, such as vegetation, helps to determine what factors underpin the social legitimacy required for effective management of these systems. This study sought to ascertain perspectives on the value of non-woody vegetation in river-floodplain systems via an online survey. The survey found that participants valued non-woody vegetation for their provision of a range of ecosystem functions and services, with strong emphasis on ecological aspects such as regulation functions, habitat provision and biodiversity. However, the inclusion of a question framed to focus on stories or narratives resulted in a different emphasis. Responses indicated that non-woody vegetation, and rivers, wetlands and floodplains were valued for the way they made people feel through lived experiences such as recreational activities, personal interactions with nature, educational and research experiences. This highlights the important role of storytelling in navigating complex natural resource management challenges and ascertaining a deeper understanding of values that moves beyond provision of function to feeling. Improved understanding of the diverse ways people value and interact with river-floodplain systems will help develop narratives and forms of engagement that foster shared understanding, empathy and collaboration. Appreciation of plural values such as the provision of functions and services along with the role of emotional connections and lived experience will likely increase lasting engagement of the general public with management to protect and restore river-floodplain systems.

Impacts of the Three Gorges Dam on riparian vegetation in the Yangtze River Basin under climate change.

As the largest hydroelectric project in the world, the Three Gorges Dam (TGD) is expected to have significant environmental and ecological impacts on riparian vegetation in the Yangtze River Basin (YRB). However, existing studies have mainly focused on small segments of the YRB. In addition, few studies have quantified the responses of riparian vegetation to both climatic factors and dam construction. In this study, we investigated riparian vegetation dynamics over the entire YRB before, during, and after the construction of TGD from 1982 to 2015 using the normalized difference vegetation index (NDVI). Furthermore, the effects of climatic factors and dam construction on riparian vegetation were quantitatively analyzed using path analysis. The results demonstrate that the YRB has experienced a generally greening trend after TGD construction. The impacts of climate change on riparian vegetation have exhibited notable spatial heterogeneity and temperature is the main climatic factor that affects riparian vegetation growth. Moreover, TGD becomes the major contributor to riparian vegetation dynamics in the YRB after TGD construction. TGD has not only directly enhanced riparian vegetation but also indirectly affected riparian vegetation by regulating the microclimate. This study highlights the significance of anthropogenic interference when evaluating the relationships between riparian vegetation and climatic factors, providing useful insights for the effective management and conservation of large-scale riparian ecosystems.

Sambucus nigra L. (fam. Viburnaceae) in Sicily: Distribution, Ecology, Traditional Use and Therapeutic Properties.

Sambucus nigra, the elderberry, has long been used for its medicinal properties in treating numerous diseases. Based on this traditional knowledge, its different pharmacological activities have been the focus of active research. All parts of the tree have long been used in traditional medicine, that is, the bark, the leaves, the flowers and the fruit. This study, carried out in Sicily (Italy), concerns the traditional uses of elder against human diseases. In order to trace the history of man's interaction with elder on the island, multidisciplinary research was carried out, aiming at (1) presenting a comprehensive overview of elderberry's applications and activities and (2) bridging traditional knowledge (uses and beliefs) with modern science, i.e., the most recent scientific findings in the biomedical and pharmacological fields. A rigorous literature review of scientific (and other local) reports on the elderberry tree and its application in food, health and household applications was undertaken. This article also provides a synthetic and updated picture of the ecology and distribution of S. nigra in Sicily. The elderberry is quite widespread in Sicily, yet its distribution is discontinuous. It prefers hedges, riparian woodlands, forest margins and clearings and is rather common along the watercourses flowing in the canyons of the Hyblaean Plateau, in the Madonie Mts. and in Enna province. Indeed, many old plants are often found near sacred places and rural houses, suggesting that in the past, it was extensively planted on purpose for its multiple uses. The complementary data obtained from multidisciplinary research confirm the usefulness of this approach in building a comprehensive and correct picture of the distribution of the most common woody species, for which the available knowledge is often fragmentary and imprecise.

Effect of sand mining on riparian landcover transformation in Dallung-Kukou catchment of the White Volta basin, Ghana.

Rapid urbanization has increased demand for sand in the construction industry to meet housing and infrastructure needs of urban population. The Dallung-Kukuo catchment of the White Volta River Basin is a major sand mining site for the construction industry in Tamale and other peri-urban communities. On the contrary, the river serves as a major source of water supply to the population. Riparian vegetation is essential to water protection, but research has focused extensively on the impact of sand mining on water quality in the river basin. The present study employed GIS and remote sensing techniques coupled with in-situ vegetation sampling to assess riparian land cover changes from 1990 to 2021. Land cover images of the catchment revealed a 14.9% increase in sand mining area, while river bed area and woodland cover decreased by 0.7% and 20%, respectively, from 1990 to 2021. A comparison of woody plant diversity also showed a higher Shannon diversity index in the unmined area of the riparian zone (3.0) compared to the sand mining area (2.0). Environmental Protection Agency and traditional authorities should intensify monitoring to protect the White Volta basin from unsustainable exploitation.

Allometric equations for estimating peak uprooting force of riparian vegetation.

Uprooting caused by flood events is a significant disturbance factor that affects the establishment, growth, and mortality of riparian vegetation. If the hydraulic drag force acting on riparian plants exceeds the peak uprooting force originate from their below-ground portion, it may result in the uprooting of these plants. Despite previous studies have documented and investigated the uprooting processes and factors influencing the peak uprooting force of plants, most of these studies have focused on how the root morphological traits of tree and shrub seedlings affect peak uprooting force or mainly collected data in indoor experiments, which may limit the extrapolation of the results to natural environments. To address these limitations, we assume that the peak uprooting force can be estimated by the morphological traits of the above-ground portion of the vegetation. In this study, we conducted in-situ vertical uprooting tests on three locally dominant species: Conyza canadensis, Daucus carota, and Leonurus sibiricus, in a typical riverine environment. The three species were found to have the highest abundance based on the outcomes of the quadrat method. We measured the peak uprooting force, plant height, stem basal diameter, shoot and root wet biomass, and shoot and root dry biomass of each plant and compared them between species. Furthermore, we quantified the influence of morphology on peak uprooting force. Our results showed significant differences in morphological traits and peak uprooting force among the three species. We found a significant positive correlation between peak uprooting force and the morphological traits of the three species. The peak uprooting force increases with plant size following a power law function which is analogous to allometric equations. The allometric equation provided a convenient and non-destructive method to estimate the peak uprooting force based on the above-ground morphological traits of the plants, which may help to overcome the limitations of measuring root morphological traits.

Hydrochorous Seed Transport in the Lower Traisen River before and after Riverbed Restoration.

Hydrological restoration was carried out in a Lower Traisen, a small river within the floodplain of the Danube. The main goal was the reestablishment of typical riparian plant communities by using the potential of natural dispersal processes. We studied the transport of plant diaspores in the river water before and after the reconstruction of the riverbed. Aquatic seed traps were placed upstream and downstream of the restoration site. We identified the transported species and tested the viability of propagules. Functional species traits were analyzed to predict the probability of successful hydrochorous dispersal and changes in the transport pool due to the restoration. One-third of the local species pool was detected as being diaspores in the river. We observed a significant increase of ruderal species and neophytes, while the competitors and stress-tolerant competitors declined. Hydrochory is an important dispersal pathway for numerous plant species in the study area, including those without specific adaptations to this vector. Hydrochorous transport appears to be a sink for large-seeded species, primarily adapted to endozoochory. Follow-up management should be recommended to control the invasive species and to improve the structural and biological diversity of the Traisen Valley by supporting target species, which are also represented in the transport pool.

Living woody vegetation as a storage element for large wood in the channel.

The stability of large wood (LW) in the channels is a prerequisite for its persisting geomorphic and ecological effects. This study analysed the factors influencing the storage of LW by living woody vegetation while still interacting with the active channel (and consequently, having potential geomorphic and ecological impact in the channel). It was conducted through field inventory of sixteen European channel reaches across various environmental settings. On the reach scale, the volumes of LW pinned by woody vegetation per channel area (0.1-18.2 m3/ha) followed global trends for total LW volumes., As the catchment area and channel width increased, and bed slope decreased, LW volumes pinned by vegetation decreased. However, the volumetric proportion of LW pinned by vegetation (1.5-30.3 %) did not increase solely as a simple function of the increasing LW mobilisation rate (represented by the increasing catchment area and channel width) or the increasing density of woody vegetation in the fluvial corridor. Instead, the specifics of the disturbance regime had an additional impact on the distribution of LW and its potential pinning on living vegetation in fluvial corridors. Moreover, stable vegetated patches in the channel were detected as significant features responsible for the pinning of LW. Only two tested reaches indicated significantly smaller dimensions of LW pinned by vegetation compared to unattached LW. This implied a possible equimobility mode of LW transport based on their sizes during flood pulses, suggesting somewhat 'random' dimensions of LW trapped by woody vegetation. This study demonstrated that woody vegetation occupying fluvial corridors cannot be solely regarded as sources of LW recruitment, but these trees and shrubs also play a crucial role as retention elements for mobilised wood during floods or other hydrogeomorphic events.

Environmental determinants of vegetation in the drawdown zones of a Columbia River Treaty reservoir: a template for ecosystem enhancement.

Water storage reservoirs alternately inundate and expose the drawdown zones, limiting riparian vegetation that provides wildlife habitats and contributes to the aquatic food-web. To characterize plant distributions and hydrogeomorphic associations, we inventoried quadrats in transects extending from the full-pool (FP) margin, downwards 12 m through the drawdown zones at sites around the Duncan Reservoir in British Columbia, Canada. Among the 69 plant species, black cottonwoods (Populus trichocarpa), willows (primarily Salix sitchensis) and other trees and shrubs occurred sparsely, rarely extending below 2 m below FP. Perennial herbaceous plants, especially horsetail (Equisetum arvense) and sedges (primarily Carex utriculata), were most common, extending down ~5 m below FP, and ruderal annual plants occurred sparsely at greater depths. Vegetation Cover and Species Richness were correlated with environmental factors, with (1) Elevation being highly influential, reflecting inundation duration and depth. (2) Position, longitudinal location, reflected greater vegetation diversity downstream of the reservoir. (3) Finer Substrate texture was favorable to retain moisture, but coarse sediments would resist erosion. (4) Shallow Slope was favorable to reduce drainage and included finer sediments. (5) Distance from the FP shoreline could reflect seed source proximity. Stepwise linear modeling with combined environmental factors accounted for ~30% of the variation in Vegetation Cover and Richness, and Canonical Correspondence Analysis revealed plant groupings relative to the environmental influences. At this and other storage reservoirs, regimes that reduce the frequency and duration of inundation could promote vegetation in locations with suitable environmental conditions in the upper drawdown zones, thus providing ecosystem enhancement.

Geomorphodynamics, evolution, and ecology of vertical roots.

The roots of some coastal and wetland trees grow peculiar vertical protrusions, the function of which remains unclear. Here, using computational simulations based on first-principles fluid and sedimentation dynamics, we argue that the protrusions work together to create an elevated patch of sediment downstream of the tree, thereby creating its own fertile flood-protected breeding grounds for the seedlings. In our simulations, we vary the vertical root diameter, root spacing and total root area and show that there is an optimal vertical root spacing that depends on root thickness. Next, we quantify and discuss the cooperative effects between adjacent vertical root patches. Lastly, by varying vertical root spacing of a patch of trees, we estimate a maximal vegetation density for which vertical-root production has a beneficial geomorphological response. Our hypothesis suggests that vertical roots, such as the 'knee roots' of baldcypress trees, have an important role in shaping riparian geomorphology and community structure.

Non-interactive effects drive multiple stressor impacts on the taxonomic and functional diversity of atlantic stream macroinvertebrates.

Freshwaters are considered among the most endangered ecosystems globally due to multiple stressors, which coincide in time and space. These local stressors typically result from land-use intensification or hydroclimatic alterations, among others. Despite recent advances on multiple stressor effects, current knowledge is still limited to manipulative approaches minimizing biological and abiotic variability. Thus, the assessment of multiple stressor effects in real-world ecosystems is required. Using an extensive survey of 50 stream reaches across North Portugal, we evaluated taxonomic and functional macroinvertebrate responses to multiple stressors, including marked gradients of nutrient enrichment, flow reduction, riparian vegetation structure, thermal stress and dissolved oxygen depletion. We analyzed multiple stressor effects on two taxonomic (taxon richness, Shannon-diversity) and two trait-based diversity indices (functional richness, functional dispersion), as well as changes in trait composition. We found that multiple stressors had additive effects on all diversity metrics, with nutrient enrichment identified as the most important stressor in three out of four metrics, followed by dissolved oxygen depletion and thermal stress. Taxon richness, Shannon-diversity and functional richness responded similarly, whereas functional dispersion was driven by changes in flow velocity and thermal stress. Functional trait composition changed along a major stress gradient determined by nutrient enrichment and oxygen depletion, which was positively correlated with organisms possessing fast-living strategies, aerial respiration, adult phases, and gathering-collector feeding habits. Overall, our results reinforce the need to consider complementary facets of biodiversity to better identify assembly processes in response to multiple stressors. Our data suggest that stressor interactions may be less frequent in real-word streams than predicted by manipulative experiments, which can facilitate mitigation strategies. By combining an extensive field survey with an integrative consideration of multiple biodiversity facets, our study provides new insights that can help to better assess and manage rivers in a global change context.

Improved statistical models for the relationship between riparian vegetation and river flow in arid environments: Implications for flow management.

Riparian vegetation (RV) provides critical ecosystem services but has been degraded worldwide due to river flow change. Quantitative relationships between RV and river flow are essential for understanding RV developments and managing flow to conserve RV. Based on the improved statistical model framework that incorporates previous RV conditions into explanatory variables to estimate later RV conditions, this study quantified the RV-flow relationships on the annual scale in the arid Ejina Delta through regression analysis coupled with the normalized difference vegetation index (NDVI) and hydrological data during 2002-2020. The median of NDVIs over the April-October growing season (SMN) was used to indicate annual vegetation conditions, and annual RV cover was derived using a dynamic SMN threshold (0.077-0.084) based on its better vegetation conditions than surrounding deserts. The water year was determined as September-August based on the defoliation time and lag time of the groundwater response to river flow. The results showed that (1) the RV cover approximately expanded from 1619 to 2914 km2, and the total SMN of RV cover increased from 3711 to 7880; (2) the spatial pattern of SMN declining away from rivers was well described by an exponential function with two physically meaningful parameters (R2 = 0.99); (3) the water-year runoff ranged from 4.0 × 108 to 10.6 × 108 m3 with an increasing trend; and (4) the annual RV condition, including both the total SMN and the spatial pattern of SMN, was well estimated by the multiple linear models incorporating a previous RV condition with a coefficient <1 and the subsequent water-year runoffs (R2 = 0.98). The results suggest that previous RV conditions are necessary to improve the rationality and performance of RV-flow relationship models, and in arid environments, annual RV conditions depend on the RV's degradation characteristics under zero flow conditions and the ecological benefit by river flow.

Developing a glyphosate-bioremediation strategy using plants and actinobacteria: Potential improvement of a riparian environment.

Glyphosate (Gly) and its principal degradation product, the aminomethylphosphonic acid (AMPA) were found in soils from a riparian environment in Argentina. Sixty-five actinobacteria were isolated from these soils, rhizosphere, and plants (Festuca arundinacea and Salix fragilis). The isolate Streptomyces sp. S5 was selected to be used as bioinoculant in a greenhouse test, in which plants, actinobacteria, and their combinations were assessed to bioremediate the riparian soil. The dissipation of both compounds were estimated. All treatments dissipated similarly the Gly, reaching 87-92 % of dissipation. AMPA, dissipation of 38 % and 42 % were obtained by Salix and Festuca, respectively, while they increased to 57 % and 70 % when the actinobacterium was added to each planted system. Regarding the total dissipation, the higher efficiencies for both compounds were achieved by the non-planted soils bioaugmented with the actinobacterium, with 91 % of Gly dissipated and 56 % for AMPA. According to our study, it could be suggested which strategy could be applied depending on the bioremediation type needed. If in situ bioremediation is necessary, the combination of phytoremediation and actinobacteria bioaugmentation could be convenient. On the other hand, if ex situ bioremediation is needed, the inoculation of the soil with an actinobacterium capable to dissipate Gly and AMPA could be the more efficient and easier alternative.

Litter inputs and standing stocks in riparian zones and streams under secondary forest and managed and abandoned cocoa agroforestry systems.

Background: Cocoa is an important tropical tree crop that is mainly cultivated in agroforestry systems (AFS). This system, known as cabruca in northeastern Brazil, holds promise to reconcile biodiversity conservation and economic development. However, since cocoa AFS alters forest structure composition, it can affect litter dynamics in riparian zones and streams. Thus, our objective was to determine litter inputs and standing stocks in riparian zones and streams under three types of forest: managed cocoa AFS, abandoned cocoa AFS, and secondary forest. Methods: We determined terrestrial litter fall (TI), vertical (VI) and lateral (LI) litter inputs to streams, and litter standing stocks on streambeds (BS) in the Atlantic Forest of northeastern Brazil. Litter was collected every 30 days from August 2018 to July 2019 using custom-made traps. The litter was dried, separated into four fractions (leaves, branches, reproductive organs, and miscellaneous material) and weighed. Results: Terrestrial litter fall was similar in all forests, ranging from 89 g m-2 month-1 in secondary forest (SF) to 96 g m-2 month-1 in abandoned cocoa AFS (AC). Vertical input were higher in AC (82 g m-2 month-1) and MC (69 g m-2 month-1) than in SF (40 g m-2 month-1), whereas lateral input were higher in MC (43 g m-2 month-1) than in AC (15 g m-2 month-1) and SF (24 g m-2 month-1). Standing stocks followed the order SF > AC > MC, corresponding to 425, 299 and 152 g m-2. Leaves contributed most to all litter fractions in all forests. Reproductive plant parts accounted for a larger proportion in managed AFS. Branches and miscellaneous litter were also similar in all forests, except for higher benthic standing stocks of miscellaneous litter in the SF. Despite differences in the amounts of litter inputs and standing stocks among the forests, seasonal patterns in the abandoned AFS (AC) were more similar to those of the secondary forest (SF) than the managed AFS, suggesting potential of abandoned AFS to restore litter dynamics resembling those of secondary forests.

The Impact of Lantana camara on Invertebrates and Plant Species of the Groenkloof Nature Reserve, South Africa.

Invasive plant species have negative ecological impacts such as displacing indigenous plants and invertebrates. These invasive plant species affect biodiversity by impacting indigenous vegetation and the food webs associated with this vegetation. We assessed how Lantana camara affects indigenous plant species richness and invertebrates and their feeding guilds in riparian habitats inside the Groenkloof Nature Reserve in South Africa. We showed: (1) A lower abundance and morphospecies richness of invertebrates as well as lower numbers of plant species in lantana-invaded habitat as compared to indigenous bush and grass-dominated habitats. (2) A Negative association between plant species richness and L. camara above ground mass and shoot density, but no association was found between plant species richness and the size of L. camara invaded areas. This finding suggests a link between the reduction in overall invertebrate abundance and morphospecies richness and the replacement of native plant species by invasive lantana. (3). This increased biomass in natural vegetation was even more evident for detrivores as compared to other feeding guilds. Extensive invasion by L. camara is affecting the quality of riparian ecosystems especially for invertebrates that rely on decaying plants and animals as food and this will affect overall biodiversity.

On the integration of LiDAR and field data for riparian biomass estimation.

The role of vegetation in supporting life on Earth is widely known. Nevertheless, the relevance of riparian corridors has been overlooked for a long time, leading to a dramatic reduction of vegetated buffers alongside them. Vegetation monitoring systems, including those for biomass estimation, are required to manage riparian corridors properly. Field surveys may support monitoring, but their usefulness is reduced by numerous drawbacks, therefore needing coupling with other data sources. The present work shows how Light Detection And Ranging (LiDAR) datasets can integrate targeted field measurements to estimate above-ground biomass at temperate or boreal latitudes and generate accurate biomass maps over large areas. By referring to the case study of the Orco river (northwest Italy), we defined a technique to reconstruct the geometry of an individual shrub from LiDAR point clouds. We tested the technique by comparing field measurements with Terrestrial and Airborne Laser Scanner data (TLS and ALS, respectively), assessing the former's superiority but the broader range of applicability of the latter. After these preliminary tests, we coupled the presented technique with a literature algorithm for individual tree detection, providing a more generalized procedure for the overall mapping and budgeting of riparian biomass based on ALS data. We applied the procedure to a fluvial bar of the Orco river, achieving a quantitative assessment of the shrub and tree biomass budget for 2019 and 2021 and visualizing the changes that occurred in that period. These results allowed us to shed light on the prevailing natural and anthropogenic processes in the investigated area and provide insights into the strengths and weaknesses of the proposed procedure.