Permanent Rivers Research Articles

Sequence Analysis of Ancient River Blocking Events in SE Tibetan Plateau Using Multidisciplinary Approaches

The temporary or permanent river blocking event caused by mass movement usually occurs on steep terrain. With the increase of mountain population and land use pressure and the construction of water conservancy and hydropower projects, river blocking events have gradually attracted people’s attention and understanding. The area in this study is affected by strong tectonic activity in the Jinsha River suture zone and the rapid uplift of the Tibetan Plateau. In the past 6000 years, there have been at least five obvious river blocking events in the reach. The number and density are very rare. Combining field investigation, indoor interpretation, laboratory tests, optically stimulated luminescence (OSL) dating, SBAS-InSAR and previous studies, multidisciplinary approaches are used to systematically summarize the analysis methods and further the understanding of one river blocking event and multiple river blocking events from different perspectives. Especially in multiple river blocking events, we can get the wrong results if interaction is not considered. Through this study, the general method of analyzing the river blocking event and the problems that should be paid attention to in sampling are given, and relatively reliable historical results of river blocking events are obtained. This method has applicability to the identification and analysis of river blocking events and age determination of dams with multiple river blockages.

Assessing the status of changing regimes of water bodies in Gorakhpur District, Uttar Pradesh, India.

Water bodies play a very important role in maintaining and restoring the ecological balance, but they are one of the most threatened habitats in the world. Anthropogenic intervention is changing the regimes of wetlands almost everywhere particularly in the developing countries. Gorakhpur District is dotted with many big and small flood plain-related water bodies like rivers, streams, tanks, dead arms, oxbow lakes, etc. Some of these water bodies are worst affected and are degraded by encroachment for agriculture and other economic and developmental activities. Channel migration, aggravated by human intervention, on alluvial plain is also very frequent, which has direct impact on the nature of water bodies and land use transformations of the region. In this paper, the authors have made an attempt to (a) bring current geographical and historical background of water bodies/wetlands for the district. It aims to assess long-term (1917-2018) and short-term (pre- and post-monsoon) changes in the water bodies of Gorakhpur District; (b) provide changes in the regime of water bodies/wetlands and their conversion to different types of land use/land cover classes due to human intervention and due to annual rainy season, which inundates a large extent of the area every year; (C) assess the channel characteristics and morphometric analysis of main rivers of the region during the last hundred years. Remote sensing and Geographical Information System (GIS) have been used to prepare the inventory and to perform change detection, using land use/land cover maps. The floodplain areas of water bodies have almost changed their morphological characters due to encroachment by the nearby areas. Canals, drainage channels, and lakes are the most affected water bodies in the region, which have recorded - 65.38% and 43.37% loss in their area. Even permanent rivers have recorded a decrease of - 16.96% in the area. As per the seasonal change, agriculture land suffered the greatest conversion (18.33%) due to floodwater inundation. The study provides a platform to planners to chalk out their policies and also for monitoring the water bodies. Furthermore, analysis on channel migration will help predict the future course of the main rivers.

First Assessment of Nocturnal Lepidopteran Communities in the Forest Savannah Mosaic of the Plateaux Batéké, Southeastern Gabon

Lepidopterans are an important component of central African biodiversity. Indeed, they play an important role as plant pollinators, food source, bio-indicators, and even pests for local crops. However, almost nothing is known about these moths in central Africa, while they are being increasingly threatened by significant landscape changes due mainly to infrastructure constructions and climate change. So, the mosaic of forests and savannah in the Plateaux Batéké (southeastern Gabon) constitutes a unique opportunity to study how Lepidopteran communities might evolve along an ecological gradient with upcoming changes in forest cover in the region. A total of 2824 specimens, representing 14 distinct families or subfamilies, were sampled using light-trapping and sorted into morphospecies, while a subset of 95 samples was further investigated using both morphological and molecular methods. Community comparison of nocturnal Lepidopteran showed that there was a significant difference in terms of abundance only between sampling sessions. Indeed, this could be due to food availability between sampling sessions. In May and June in Gabon, most plants have flowers and fruits and moth families such as Geometridae and Sphingidae emerge at that time. The most represented family in our sampled specimens was the Geometridae, which prefers habitats with permanent river courses as is the case in our sampling area. However, a more comprehensive study using various trapping methods, during several seasonal cycles and with more replicates in each habitat type is needed for a better understanding of the community structure and ecological traits that characterize nocturnal Lepidopteran in the Plateaux Batéké of Gabon.

Random forest and extreme gradient boosting algorithms for streamflow modeling using vessel features and tree-rings

Monitoring temporal variation of streamflow is necessary for many water resources management plans, yet, such practices are constrained by the absence or paucity of data in many rivers around the world. Using a permanent river in the north of Iran as a test site, a machine learning framework was proposed to model the streamflow data in the three periods of growing seasons based on tree-rings and vessel features of the Zelkova carpinifolia species. First, full-disc samples were taken from 30 trees near the river, and the samples went through preprocessing, cross-dating, standardization, and time series analysis. Two machine learning algorithms, namely random forest (RF) and extreme gradient boosting (XGB), were used to model the relationships between dendrochronology variables (tree-rings and vessel features in the three periods of growing seasons) and the corresponding streamflow rates. The performance of each model was evaluated using statistical coefficients [coefficient of determination (R-squared), Nash–Sutcliffe efficiency (NSE), and root-mean-square error (NRMSE)]. Findings demonstrate that consideration should be given to the XGB model in streamflow modeling given its apparent enhanced performance (R-squared: 0.87; NSE: 0.81; and NRMSE: 0.43) over the RF model (R-squared: 0.82; NSE: 0.71; and NRMSE: 0.52). Furthermore, the results showed that the models perform better in modeling the normal and low flows compared to extremely high flows. Finally, the tested models were used to reconstruct the temporal streamflow during the past decades (1970–1981).

Vernal pools enhance local vertebrate activity and diversity in a boreal landscape

Biodiversity and habitats are under threat from many factors such as human population increase, habitat loss, fragmentation, and climate change. In freshwater habitats, including wetlands, biodiversity is expected to decline on a greater scale than in terrestrial ecosystems. Ephemeral wetlands are little studied habitats compared to other wetlands, such as permanent lakes and rivers. The purpose of this study was to investigate the vertebrate fauna present by ephemeral vernal pools and to see whether vernal pools increase the activity and diversity of vertebrates in a boreal forest ecosystem in northern Europe. We studied the activity and species richness of birds and mammals with direct observations, camera traps, feces tracking, and snap-trapping by ten vernal pools and ten permanent wetlands. Bird activity was higher in the spring period in vernal pools than in permanent wetlands. For large mammals, both activity and species richness were greater around vernal pools than by permanent wetlands. Of individuals species, the moose ( Alces alces ), roe deer ( Capreolus capreolus ), and hares ( Lepus europaeus and Lepus timidus ) used vernal pools significantly more between seasons compared to permanent wetlands. Small mammal activity was higher by vernal pools in April, while in May and June the pattern reversed. In the light of these results, vernal pools seem to have different importance and use depending on the vertebrate group, e.g., for sheltering, foraging, resting, nesting, or thermoregulation.

Seasonal and geographic variation in packed cell volume and selected serum chemistry of platypuses

Platypuses (Ornithorhynchus anatinus) inhabit the permanent rivers and creeks of eastern Australia, from north Queensland to Tasmania, but are experiencing multiple and synergistic anthropogenic threats. Baseline information of health is vital for effective monitoring of populations but is currently sparse for mainland platypuses. Focusing on seven hematology and serum chemistry metrics as indicators of health and nutrition (packed cell volume (PCV), total protein (TP), albumin, globulin, urea, creatinine, and triglycerides), we investigated their variation across the species’ range and across seasons. We analyzed 249 unique samples collected from platypuses in three river catchments in New South Wales and Victoria. Health metrics significantly varied across the populations’ range, with platypuses from the most northerly catchment, having lower PCV, and concentrations of albumin and triglycerides and higher levels of globulin, potentially reflecting geographic variation or thermal stress. The Snowy River showed significant seasonal patterns which varied between the sexes and coincided with differential reproductive stressors. Male creatinine and triglyceride levels were significantly lower than females, suggesting that reproduction is energetically more taxing on males. Age specific differences were also found, with juvenile PCV and TP levels significantly lower than adults. Additionally, the commonly used body condition index (tail volume index) was only negatively correlated with urea, and triglyceride levels. A meta-analysis of available literature revealed a significant latitudinal relationship with PCV, TP, albumin, and triglycerides but this was confounded by variation in sampling times and restraint methods. We expand understanding of mainland platypuses, providing reference intervals for PCV and six blood chemistry, while highlighting the importance of considering seasonal variation, to guide future assessments of individual and population condition.

Consanguinity: A Form of Social Capital Among the Muslims of Char Areas in Barpeta District, Assam

Information on the dynamics of consanguinity is always important for public health strategy. It provides a direct roadmap for healthcare providers and health policymakers to make people aware of the consequences of consanguinity. The present study aims to investigate the attitude of the Muslim people practising consanguinity in the char (river island) areas of Barpeta district in Assam. It intends to seek a cultural explanation behind the practice of consanguinity. The study was conducted cross-sectionally among the Muslims living in different villages of the temporary, semi-permanent and permanent river islands of Barpeta district in Assam. A total of 556 married couples were included in the study. Of these, 103 couples are consanguineous and the rest 453 are non-consanguineous. To study the prevalence of congenital disorders, a sample of 153 males and 121 female inbred children of the consanguineous couples and 701 male and 571 female children of the non-consanguineous parents have been included in the study. The prevalence of consanguineous marriage in the chars was found to be 18.53% and the average coefficient of inbreeding was 0.05996796. Of the consanguineous marriages, the most favoured type was between the first cousins (63.11%), followed by half first-cousin marriages (12.62%). Altogether 14.60% of inbred were found to have some type of congenital disorder against 0.31% non-inbred. In the chars of Barpeta, it is not only ignorance but poor economic condition is also a reason behind the practise of consanguinity. Consanguineous marriage provides means of escaping the expenditure incurred in dowry or bridewealth payment. With seasonal floods, river erodes their village and crops completely every year. Family remains the sole source of stability and security. Consanguineous marriage therefore forms a sort of social capital as they are a source of secured and stable married life in the most hostile ecological settings where these people are living. Social security is of utmost priority behind these marriages in the char.

Discharge of treated wastewater: hydrodynamic and hydrogeochemical impacts on the Kairouan plain aquifer (Central Tunisia)

In Tunisia, the discharge of treated wastewater onto land area has become a common practice, especially in arid and semi-arid regions where there are no permanent rivers to receive discharge. Treated wastewater constitutes a potential anthropogenic source of aquifer recharge as is the case for the alluvial aquifer downstream of the Kairouan plain. This alluvial aquifer receives annually an average volume of 4.9 hm3 of treated wastewater from the Dhraa Tammar wastewater treatment plant, which is discharged over a land area of 182 ha. This research presents the first piezometric and hydrogeochemical characterization of Kairouan plain shallow groundwater and the assessment of treated wastewater impacts on groundwater piezometric levels, salinity and hydrogeochemical composition and microbiological contents of groundwater. To achieve these objectives, a piezometric surveys of 15 shallow wells was undertaken. Additionally, groundwater and treated wastewater samples were collected in February and April 2017 for chemical and microbiological analysis. The piezometric study shows that treated wastewater discharge induces a local increase of the water table level materialized by the appearance of a piezometric dome (a height estimated at 1.5 m) in the discharge site during a period of 4 years (2014–2017). Shallow groundwater downstream of Kairouan plain shows a naturally high mineralization state (a salinity more than 20 g L−1) caused by natural mineralization process. A considerable reduction of groundwater salinity (between 3 and 10 g L−1) is observed in the discharge site due to treated wastewater infiltration. Discharge of treated wastewater has caused an increase of groundwater bicarbonate concentration due to leaching of organic matter and local microbiological groundwater contamination (250–450 fecal germs per 100 ml) in the discharge site.

Heterogeneity in African savanna elephant distributions and their impacts on trees in Kruger National Park, South Africa.

Though elephants are a major cause of savanna tree mortality and threaten vulnerable tree species, managing their impact remains difficult, in part because relatively little is known about how elephant impacts are distributed throughout space.This is exacerbated by uncertainty about what determines the distribution of elephants themselves, as well as whether the distribution of elephants is even informative for understanding the distribution of their impacts.To better understand the factors that underlie elephant impacts, we modeled elephant distributions and their damage to trees with respect to soil properties, water availability, and vegetation in Kruger National Park, South Africa, using structural equation modeling.We found that bull elephants and mixed herds differed markedly in their distributions, with bull elephants concentrating in sparsely treed basaltic sites close to artificial waterholes and mixed herds aggregating around permanent rivers, particularly in areas with little grass.Surprisingly, we also found that the distribution of elephant impacts, while highly heterogeneous, was largely unrelated to the distribution of elephants themselves, with damage concentrated instead in densely treed areas and particularly on basaltic soils.Results underscore the importance of surface water for elephants but suggest that elephant water dependence operates together with other landscape factors, particularly vegetation community composition and historical management interventions, to influence elephant distributions.

Vegetation zonation along the desert-wetland ecosystem of Taif Highland, Saudi Arabia.

Saudi Arabia has no permanent lakes or rivers but has wet meadows, which are desert wetlands temporarily formed due to the seasonal rainfall. This work investigates the environmental variables' impact on the vegetation pattern in the desert-wetland ecosystem in Taif highlands. Forty-one stands were randomly selected representing three main habitats (wet meadows, slopes, and terraces) to study their floristic features and vegetation analysis. A total of 142 species were recorded belonging to 111 genera and 45 families in the desert wetlands of Taif Province. About 64.1% were natural plants, while 25.4% were segetal weeds, 7.7% were aquatic plants, and 2.8% were plants that escaped from cultivation. Therophytes dominated over the other life forms, and mono-regional taxa were the dominant chorotype. Multivariate analysis of the recorded plants produced eight vegetation groups; four of them (A: Potamogeton nodosus-Nasturtium officinale, B: Lemna gibba-Leptochloa fusca, C: Typha domingensis- Xanthium strumarium and D: Conyza stricta- Cyperus longus) represented the wet meadows, while two (E: Acacia gerrardii- Commicarpus plumbagineus and H: Osteospermum vaillantii- Eragrostis Pilosa) for slopes and other two (F: Argemone ochroleuca-Cyperus rotundus and G: Pulicaria undulata- Solanum incanum) for the desert terraces. The vegetation zonation was clear, which started from real aquatic species in the wet meadows passing through mixed vegetation in the slopes and ended with proper xerophytic vegetation in the terraces. Conyza stricta- Cyperus longus community had the highest species diversity, while that of Potamogeton nodosus-Nasturtium officinale had the lowest. The principal component analysis indicated that HCO3, NO3, Mg, Cl, Ca, and pH values were the most effective soil variable. The presence of several segetal weeds suggests the alteration of the natural status of the desert-wetland ecosystem, and thus the conservation of these natural habitats becomes urgent.

Wildlife roadkill in the Tsavo Ecosystem, Kenya: identifying hotspots, potential drivers, and affected species

Roadkill is one of the highest causes of wildlife mortality and is of global conservation concern. Most roadkill studies have focused on wildlife in developed countries such as the United States of America and temperate biomes, but there are limited data for the impacts of roads on wildlife in the African tropics, where road infrastructure development is projected to grow rapidly in natural environments and conservation areas. The Tsavo Conservation Area is an important biodiversity hotspot in eastern Kenya and is bisected by a major highway and railways that connect the port of Mombasa to the interior. Along this infrastructure corridor, roadkill was recorded for 164 days over an 11-year period (2007–2018). In total, 1,436 roadkill were recorded from 13,008 km driven of a 164.42 km Nairobi-Mombasa road representing 0.11 collisions per kilometer. The majority of roadkill were small to medium sized mammals (<15kg) (53%; n = 756), whereas birds comprised 32% (n = 460), reptiles 10% (n = 143), with the remaining 5% (n = 77) being large mammals (>15kg). Of the 460 birds recorded, 264 were identifiable represented by 62 species. All large mammals comprising 10 species were identified, including the African elephant, Loxodonta africana and the endangered African wild dog, Lycaon pictus. Thirteen species of small mammal were also identified dominated by Kirk's dik-dik (Madoqua kirkii). Reptiles were represented by 11 species which were identified to the species level. Roadkill hotspots were identified using a kernel density method. The spatial distribution of roadkill was associated with adjacent shrub vegetation and proximity to permanent and seasonal rivers, and differences in seasonality and habitats were observed. Roadkill was lowest on road sections that traversed settled areas as opposed to roads adjacent to the protected areas. The results demonstrate that roadkill for two of the taxonomic groups - mammals and birds - appear high with numerous species detected in the Tsavo Conservation Area. These results can be used to focus efforts to reduce wildlife mortality by guiding future mitigation efforts.

Partial migration of a maraena whitefish Coregonus maraena population from the River Elbe, Germany

The maraena whitefish Coregonus maraena is a threatened anadromous species in the North Sea, which in the past was decimated to near extinction. Since the late 1980s, several re-establishment programs have been implemented in rivers draining into the North Sea, but the scientific basis for sustainable conservation measures is often lacking, since little is known about the biology of this species. In this study, otolith microchemistry of fish ranging from 24.6 to 58.4 cm in total length (median 31.3 cm, SD 8.4 cm) was used to characterize the migration behavior of a reintroduced population of maraena whitefish from the River Elbe, Germany. Our analyses revealed the presence of 3 different migration patterns: (1) one-time migration into high-salinity habitat (North Sea) within the first year of life (29.6%), (2) multiple migrations between low- and high-salinity habitats starting in the first year of life (14.8%) and (3) permanent residency within low-salinity habitats, a pattern displayed by the majority (55.6%) of sampled individuals. Not only do these results reveal differential migration behavior, but they also indicate that permanent river residency is common in the River Elbe population of C. maraena. The role of the Elbe as both a feeding and a spawning habitat should thus be considered more explicitly in current conservation measures to support recovery of this species.

Distribution of wetlands and salt lakes in the Yadong region of Tibet based on remote sensing, and their geo-climatic environmental changes

Based on the 16 scenes GF-1 satellite multi-spectral remote sensing images, through the adoption of data processing methods including orthorectification, geometric rectification, data fusion and image mosaic, integrated with field surveys, the remote sensing interpretation signs for the inland wetland types have been built, and the remote sensing survey of inland wetlands in Yadong region has been initiated, with six types of inland wetlands recognized in Yadong region, namely permanent rivers, seasonal rivers, lakes, salt lakes, alpine meadows, and inundated land. The spatial distribution characteristics and the spreading rules of these wetlands have also been revealed. Based on full understanding of the overall characteristics of the inland wetlands in the Yadong region, using the three phases of TM images acquired in 1989, 2003 and 2008 as well as the PMS2 data gathered by GF-1 in 2014, and the wide-range data (WFV3) gathered by GF-1 in 2020. As to the typical salt lakes, a long- time salt lakes transition study was carried out. The results show that the typical salt lakes in Yadong have been shrinking in the past three decades. The average annual shrinkage of Duoqing Co (Co means lake in Tibetan) was stronger than that of Gala Co, which are respective 87.30 hectares (usually short as ha; 1 ha equals to 0.01 km2) /a and 24.20 ha/a; the shrinkage degree of Gala Co was higher than that of Duoqing Co, shrank by 59.27% and 35.73% respectively. Based on the remote sensing survey results and an integrated analysis of the predecessors’ researchers, the reason for the shrinkage of the salt lakes is more inclined to geological factors. Geological process is manifested by a series of extensional faults at the bottom of the lake basin generated from tectonic activities, providing fluid infiltration channels, and inducing the eventual leakage of lake water to the lower strata. The result provides an important instance for understanding the evolution characteristics of wetlands and salt lakes in specific environment of the Tibetan Plateau.©2022 China Geology Editorial Office.

Urmia Gölü'nün batı drenajından Türkiye faunası için üç yeni tatlısu balık türü kaydı

In the scope of this study, three freshwater fish species were newly recorded for Turkey from a western drainage of Lake Urmia: Alburnoides petrubanarescui, Alburnus atropatenae and Oxynoemacheilus elsae. All of them were found in headwaters of Nazli-chay River in the basin of the hypersaline Lake Urmia. The Lake is fed by many small springs and thirteen permanent rivers. In the previous studies, the existence of a stream in the western part of the Urmia Lake within border of Turkey was not mentioned.

Reconsideration of an origin of the spring water which forms permanent river at the Higashi-yama Mountain, Hachijo Island

Reconsideration of an origin of the spring water which forms permanent river at the Higashi-yama Mountain, Hachijo Island

Does invasive river red gum (Eucalyptus camaldulensis) alter leaf litter decomposition dynamics in arid zone temporary rivers?

ABSTRACT Riparian zones are important for the maintenance of aquatic ecosystem functional integrity, yet are considered to be particularly vulnerable to plant invasions. The role of terrestrial riparian plant invasions in compromising aquatic ecosystem processes is, however, still poorly understood. This issue is particularly relevant for temporary rivers, which are understudied compared to permanent river systems, despite their ubiquity and largescale contributions to biogeochemical processes. Here we experimentally assessed leaf litter breakdown dynamics in situ in a temporary river in arid southeastern Botswana, Southern Africa. We contrasted aquatic leaching and microbial and invertebrate litter breakdown contributions to the native leadwood Combretum imberbe and invasive river red gum Eucalyptus camaldulensis in the Lotsane River. Fine-mesh (detritivore exclusion) and coarse-mesh (detritivore inclusion) bags were separately filled with leaf litter from each species and deployed in the river during a hydroperiod (wet phase), with decomposition measured over a 6-week period. E. camaldulensis shed significantly more leachate than the native C. imberbe. Significantly more microbial and detritivore breakdown was, however, observed in native than in invasive leaf litter. Overall, invertebrates contributed little to biological leaf litter breakdown processes compared to microbial breakdown contributions. Although significantly higher in native leaves, low invertebrate numbers were found in leaf litter in the study. This study highlights the role of microbial contributions to detrital decay in temporary arid zone rivers, whereas invertebrate contributions were relatively minor. The study further contributes to our understanding of how invasive riparian plant species alter aquatic detrital pool dynamics in invaded temporary wetland ecosystems.

EVALUATION OF PERMANENT RIVER ISLANDS OF EUPHRATES RIVER WITHIN KUFA-MISHKHAB SECTOR USING REMOTE SENSING APPLICATIONS, MIDDLE OF IRAQ

River islands present one of the important geomorphological features within the rivers streams that are formed due to the long and continuous moving of the waterway. Ten permanent river islands of Euphrates river within Kufa-Mishkhab sector have been selecting for studying and evaluation the geomorphological situations of the permanent river islands using remote sensing in the years 2002-2018. It was noted that the river islands of Euphrates river have been affected during the years of 2002-2018 in the river currents as well as varying in the size and shape of the islands due to the extent of the river stream, low slopes river floor, the curvature of the river, the type of the lithological sedimentary formations stream and type of the sediments loaded.

Evaluation of heavy metal pollution in the Zayandeh-Rud River as the only permanent river in the central plateau of Iran.

Zayandeh-Rud River is the only permanent river in the central plateau of Iran. This river has been subject to an extensive discharge of wastewater and effluents from several point and nonpoint pollution sources. Accordingly, sediment quality of Zayandeh-Rud River in Varzaneh region, were studied. Algae and the sediment were sampled through 3 replications at 6 stations in the downstream after crossing through the Isfahan city and reaching Gavkhuni international wetland. Chlorophyll content and As, Pb, and Cd concentrations were measured in each sample Cladophora sp. and Oscillatoria sp. were identified using standard identification keys. The mean concentrations of metals in all stations exceeded background levels. Mean concentration of arsenic (162.9mg/kg) in the sediment is about 31 times more than the ISQG standard (5.9mg/kg) and considerably higher than the similar studies in Iran and other regions of the world. The mean concentration of As in algae samples is higher than the most polluted areas of the world. The mean concentration of Pb in the sediment (19.69mg/kg) is lower than the ISQGs standard (35mg/kg) and most of the studied river in north of Iran such as Chalous, Baboul-Rud, Gorgan-Rud (North), Khiav (North West), and Anzali wetland. The mean concentration of Cd in the sediment (2.11mg/kg) is significantly higher than ISQG standard (0.6mg/kg and some north highly polluted wetlands of Iran such as Anzali. There is a significant positive correlation between the mean concentrations of As and Pb in the sediment and Cladophora sp. tissue, and a negative one between the mean concentration of Pb in the sediment and chlorophyll b/a. There are significant negative correlations between the mean concentration of As in the sediment and chlorophyll a, and the total chlorophyll concentration in Oscillatoria sp. The results of Muller index indicate that the concentrations of Pb, Cd, and As in all stations occur in the Unpolluted, Moderate/Heavy, and Heavy/Extreme groups, respectively. Degree of contamination and modified degree of contamination show very high degree of pollution in the studied area. RI in all the stations showed very high ecological risk. The bioaccumulation factor for all metals in both algae is less than one. So, these two species may not be described as heavy metal accumulators. This study is an alarm for the Zayandeh-Rud River as the most important freshwater source for the Iranian Plateau. Graphical abstract.

A river runs through it: The causes, consequences, and management of intraspecific diversity in river networks.

Rivers are fascinating ecosystems in which the eco‐evolutionary dynamics of organisms are constrained by particular features, and biologists have developed a wealth of knowledge about freshwater biodiversity patterns. Over the last 10 years, our group used a holistic approach to contribute to this knowledge by focusing on the causes and consequences of intraspecific diversity in rivers. We conducted empirical works on temperate permanent rivers from southern France, and we broadened the scope of our findings using experiments, meta‐analyses, and simulations. We demonstrated that intraspecific (genetic) diversity follows a spatial pattern (downstream increase in diversity) that is repeatable across taxa (from plants to vertebrates) and river systems. This pattern can result from interactive processes that we teased apart using appropriate simulation approaches. We further experimentally showed that intraspecific diversity matters for the functioning of river ecosystems. It indeed affects not only community dynamics, but also key ecosystem functions such as litter degradation. This means that losing intraspecific diversity in rivers can yield major ecological effects. Our work on the impact of multiple human stressors on intraspecific diversity revealed that—in the studied river systems—stocking of domestic (fish) strains strongly and consistently alters natural spatial patterns of diversity. It also highlighted the need for specific analytical tools to tease apart spurious from actual relationships in the wild. Finally, we developed original conservation strategies at the basin scale based on the systematic conservation planning framework that appeared pertinent for preserving intraspecific diversity in rivers. We identified several important research avenues that should further facilitate our understanding of patterns of local adaptation in rivers, the identification of processes sustaining intraspecific biodiversity–ecosystem function relationships, and the setting of reliable conservation plans.

Variation in behavioral traits of two frugivorous mammals may lead to differential responses to human disturbance.

Human activities can lead to a shift in wildlife species’ spatial distribution. Understanding the specific effects of human activities on ranging behavior can improve conservation management of wildlife populations in human‐dominated landscapes. This study evaluated the effects of forest use by humans on the spatial distribution of mammal species with different behavioral adaptations, using sympatric western lowland gorilla and central chimpanzee as focal species. We collected data on great ape nest locations, ecological and physical variables (habitat distribution, permanent rivers, and topographic data), and anthropogenic variables (distance to trails, villages, and a permanent research site). Here, we show that anthropogenic variables are important predictors of the distribution of wild animals. In the resource model, the distribution of gorilla nests was predicted by nesting habitat distribution, while chimpanzee nests were predicted first by elevation followed by nesting habitat distribution. In the anthropogenic model, the major predictors of gorilla nesting changed to human features, while the major predictors of chimpanzee nesting remained elevation and the availability of their preferred nesting habitats. Animal behavioral traits (body size, terrestrial/arboreal, level of specialization/generalization, and competitive inferiority/superiority) may influence the response of mammals to human activities. Our results suggest that chimpanzees may survive in human‐encroached areas whenever the availability of their nesting habitat and preferred fruits can support their population, while a certain level of human activities may threaten gorillas. Consequently, the survival of gorillas in human‐dominated landscapes is more at risk than that of chimpanzees. Replicating our research in other sites should permit a systematic evaluation of the influence of human activity on the distribution of mammal populations. As wild animals are increasingly exposed to human disturbance, understanding the resulting consequences of shifting species distributions due to human disturbance on animal population abundance and their long‐term survival will be of growing conservation importance.