Riverine Habitats Research Articles

Length–weight relationships of seven small indigenous fish species from the Tapti River in peninsular India

AbstractLength–weight relationships of seven small indigenous fishes collected from the middle and lower stretch of the Tapti River in India were determined. The specimens were caught with drag nets (0 mm mesh size), gill nets (10–20 mm knot‐to‐knot mesh length) and scoop nets (0 mm) from the Maharashtra, and Gujarat state stretches of the Tapti River from November 2018 to December 2019. Digital calliper and digital balances were used to measure the total length (TL) and body weight (BW) of all fish specimens respectively. The growth coefficient b varied from 2.758 (Parambassis ranga) to 3.298 (Osteobrama cotio), and the LWRs were highly significant (p < .005). The present study established LWRs for the first time for seven fish species in the respective riverine habitat, including providing a new maximum length record for Corica soborna. The results of the present study will be useful for sustainable management and conservation of respective species in the river and its associated waterbodies.

Middle Holocene Environment on the Ozark Margin in Southeast Missouri: Deciphering a Testudine Testament

Turtle taxa represented at Lepold site 23RI59 in southeastern Missouri, USA provide a record of environmental conditions spanning the Middle Holocene. Identified turtle taxa show that open water was present between 7500 and 4000 radiocarbon years ago. Aquatic resources seem to be more intensively exploited beginning about 6300 years ago, about 1200 years after intensive occupation of the site had begun. The observed turtle taxon composition is consistent with the presence of a floodplain with shallow, seasonal, overflow ponds, but with riverine and upland habitats also being represented.

EDEL DANCE: A HEALING RITUAL OF TAGAKAULO TRIBE OF BARANGAY DATU DANWATA IN MALITA, DAVAO OCCIDENTAL

For millennia, faith healing has been practiced in many nations to prevent, diagnose, and treat health issues (Peprah, P., et al., 2019). Faith healing is the concept that by having faith, one may be healed. Prayer or supernatural intervention are generally used to accomplish this. The goal of this research is to learn more about Edel Dance: A Healing Ritual of the TagaKaulo Tribe in Barangay Datu Danwata, Malita, Davao Occidental, Philippines. Storytelling, focus group discussions, observations, and in-depth interviews are all used by the researcher. Families that took part in the Edel Dance enjoyed spiritual, bodily, and emotional healing, especially when a sibling died. Their God, who created humanity and the cosmos, was tied to this concept. As a result, traditional methods of thinking and doing things have been preserved and continue to be practiced today. The Tagakaulo Tribe has traditionally resided in the provinces of Davao Del Sur and Sarangani, particularly in the towns of Malalag, Lais, and Talaguton Rivers, Santa Maria, Davao Occidental, and Malita and Malungon, Sarangani. The Tagakaolo tribe traveled south of Mt. Apo from the Davao Gulfs western beaches a long time ago. There are around 71,356 native speakers in the country (2000, SIL International). Tagakaulo is connected to the Mandaya, Kalagan, and Kamayo dialects and belongs to the Austronesian and Malayo-Polynesian language families. Tagakaulo means headwater dwellers (olo sa tubig) or headwater dwellers (olo sa tubig) or headwater dwellers (olo sa tubig) or headwater dwellers (olo sa tubig Lowland, coastal, riverine, valley, mountain, highland, and plain habitats were all present. Their main sources of income were agriculture, fishing, and paid labor, and they lived completely sedentary lives. Primogeniture runs across each upland river valley or highland plain (right of succession belonging to the firstborn child). The datu, who is in charge of civic and labor obligations, is a significant person in their culture; a powerful datu may be captured or purchased. Each datu is the self-governing chief of a region. The Tagakaulo tribe’s lifestyle is influenced by religious beliefs, ceremonies, and customs. They are touched by supernatural phenomena because they think ghosts are also part of the community. Their religious views represent their relationship with the divine realm, which has an impact on how they should act, behave, and interact with the unseen world. As a result, traditional belief systems and rituals have survived and continue to be practiced today. All aspects of our life are influenced by cultural belief systems and customs. As a result, in order to preserve these notions and traditions, research that is in tune with other cultures beliefs and practices should be promoted. Furthermore, studies like these will aid in the spread of understanding as well as acceptance and respect for diverse faiths views, practices, and faith. KEYWORDS: Edel Dance, healing,Tagakaulo Tribe, Faith healing

Length Weight Relationship and Condition Factor of Labeo rohita (Ham.) Collected from Domesticated and Riverine Habitats

Length Weight Relationship and Condition Factor of Labeo rohita (Ham.) Collected from Domesticated and Riverine Habitats

Length-weight relationship and condition factor of selected small Cyprinid fishes from river Burhi Gandak in North Bihar, India

The present study was conducted in Burhi Gandak River in Bihar to investigate the length-weight relationship and condition factor of four small cyprinids viz. Cirrhinus reba (Hamilton, 1822), Puntius sophore (Hamilton, 1822), Puntius terio(Hamilton, 1822) and Ambylpharyngodon mola (Hamilton, 1822). A total of 677 C. reba, 969 P. sophore, 873 P. terio and 1015 A. mola specimens were collectedusing traditional boats and some locally made nets like Dhoni jaal, Auptha jaal, Chauni jaal and modified traps. The regression equation was found as Log W = -2.036 + 2.97 Log L (r=0.94) for Cirrhinus reba, Log W = -1.962 + 3.14 Log L (r=0.84) for Puntius sophore, Log W = -0.932 + 1.86 Log L (r=0.72) for Puntius terio and Log W = -2.031 + 3.39 Log L (r=0.84) for Ambylpharyngodonmola. The length weight relationship revealed that C. reba follows the isometric growth pattern while P. sophore and A. mola exhibit positive allometric growthpattern and negative growth pattern was observed in P. terio. The variation in condition factor was observed in case of P. terio while the other species are in good condition in this riverine habitat.

Community assembly, functional traits, and phylogeny in Himalayan river birds.

Heterogeneity in riverine habitats acts as a template for species evolution that influences river communities at different spatio‐temporal scales. Although birds are conspicuous elements of these communities, the roles of phylogeny, functional traits, and habitat character in their niche use or species' assembly have seldom been investigated. We explored these themes by surveying multiple headwaters over 3000 m of elevation in the Himalayan Mountains of India where the specialist birds of montane rivers reach their greatest diversity on Earth. After ordinating community composition, species traits, and habitat character, we investigated whether river bird traits varied with elevation in ways that were constrained or independent of phylogeny, hypothesizing that trait patterns reflect environmental filtering. Community composition and trait representation varied strongly with increasing elevation and river naturalness as species that foraged in the river/riparian ecotone gave way to small insectivores with direct trophic dependence on the river or its immediate channel. These trends were influenced strongly by phylogeny as communities became more clustered by functional traits at a higher elevation. Phylogenetic signals varied among traits, however, and were reflected in body mass, bill size, and tarsus length more than in body size, tail length, and breeding strategy. These variations imply that community assembly in high‐altitude river birds reflects a blend of phylogenetic constraint and habitat filtering coupled with some proximate niche‐based moulding of trait character. We suggest that the regional co‐existence of river birds in the Himalaya is facilitated by this same array of factors that together reflect the highly heterogeneous template of river habitats provided by these mountain headwaters.

Introducing HyPeak: An international network on hydropeaking research, practice, and policy

AbstractAn increase in the demand for renewable energy is driving hydropower development and its integration with variable renewable energy sources. When hydropower is produced flexibly from hydropower plants, it causes rapid and frequent artificial flow fluctuations in rivers, a phenomenon known as hydropeaking. Hydropeaking and associated hydrological alterations cause multiple impacts on riverine habitats with cascading effects on ecosystem functioning and structure. Given the significance of its ecological and socio‐economic implications, mitigation of hydropeaking requires an inter‐ and transdisciplinary approach. An interdisciplinary network called HyPeak has been conceived to enrich international research initiatives and support hydropower planning and policy. HyPeak has been founded based on exchange and networking activities linking scientists from several countries where hydropeaking has been widespread for decades and numerous studies dedicated to the topic have been carried out. HyPeak aims to integrate members from other countries and continents in which hydropower production plays a relevant role, and grow to be a reference group that provides expert advice on the topic to policy‐makers, as well as researchers, stakeholders, and practitioners in the field of hydropeaking.

The Impact of Hydromorphological Alterations on Mayfly Assemblages of a Mid-Sized Lowland River in South-Eastern Europe.

Simple SummaryThe majority of European lowland rivers are under the impact of multiple stressors (water quality, hydromorphological alterations, land-use), however, the consequences of these influences on mayflies have not been sufficiently studied. Therefore, we studied mayfly assemblages and their relationship to environmental factors along a mid-sized lowland river in Croatia. No significant differences in mayfly species richness and their functional traits were observed among the three habitat groups with different levels of hydromorphological alterations (near-natural, moderately altered, and severely altered habitats). This could be related to the river’s connection to the numerous tributaries, and the variety of available microhabitats along the studied system, despite the existing hydromorphological pressures. A stronger relationship was found between mayflies and the water physico-chemical characteristics (water temperature, water velocity, oxygen content, and nutrient (e.g., nitrogen, phosphorous) concentrations) and agricultural and urban land-use. These results can contribute to the planning of management and conservation activities for lowland rivers and their biota according to the requirements of the European Water Framework Directive.Historically, rivers have been anthropogenically modified for different purposes worldwide (e.g., flood control, drinking water abstraction, and land drainage). Although the majority of European lowland rivers are under the impact of multiple stressors (water quality, hydromorphological alterations, land-use), the consequences of these influences on aquatic macroinvertebrates, including mayflies, have not been sufficiently studied. Therefore, with the aim of providing additional data on the response of mayflies to anthropogenic disturbances in riverine habitats, we studied mayfly assemblages and their relationship to environmental factors along a mid-sized lowland river in Croatia. No significant differences in mayfly species richness and their functional traits were observed among the three habitat groups with different levels of hydromorphological alterations (near-natural, moderately altered, and severely altered habitats). This could be related to the river’s connection to the numerous tributaries, and the variety of available microhabitats along the studied system, despite the existing hydromorphological pressures. A stronger relationship was found between mayflies and the physico-chemical water characteristics and land-use. Water temperature, water velocity, oxygen content, and nutrient (e.g., nitrogen, phosphorous) concentrations related to agricultural and urban land-use were found to be the most important factors shaping mayfly assemblages in the studied lotic lowland system. These results can contribute to the planning of management and conservation activities for lowland rivers and their biota according to the requirements of the European Water Framework Directive.

The diversity of plant species in the proboscis monkey’s habitat as a species reference for habitat restoration

Most of the Proboscis monkey (Nasalis larvatus) habitat is outside the protected area, so the potential for destruction is high. One of the efforts to improve its habitat is habitat restoration. This study aims to determine plant species for proboscis monkey habitat restoration based on reference habitats. The research was conducted at eight locations in East Kalimantan, Indonesia i.e. Kuala Samboja, Mahakam Delta, Suwi River, Ohong River, Berau Delta (mangrove and riverine), Sungai Wain, and Kutai National Park. Vegetation analysis with line-plot sampling method with a total sample of all locations of 11.7 ha. The results showed that the habitat included three main types: mangrove, riverine, and riverine-near coastal. A total of 152 tree species, 41 of which were potential proboscis monkey feed. The highest plant species diversity value was in the riverine forest-Berau Delta of 1.25, while the lowest was in the mangrove forest-Berau Delta of 0.54. Species that are a food source and have good adaptation in riverine habitat are Vitex pinnata, Dillenia excelsa, Garcinia spp, Heritiera littoralis, Ilex cymosa, Cerbera manghas, Hevea braziliensis, and Sonneratia caseolaris. Whereas in mangrove habitat are Avicennia alba, A. officinalis, Bruguiera gymnorrhiza, B. parvifolia, Rhizophora apiculata, and S. alba. They are recommended for habitat restoration.

A noninvasive eDNA tool for detecting sea lamprey larvae in river sediments: Analytical validation and field testing in a low-abundance ecosystem.

Anthropogenic activities are increasingly threatening aquatic biodiversity, especially anadromous species. Monitoring and conservation measures are thus required to protect, maintain and restore imperilled populations. While many species can be surveyed using traditional capture and visual census techniques, species that use riverine habitats in a less conspicuous manner, such as sea lamprey Petromyzon marinus, can be more challenging to monitor. Sea lamprey larvae (ammocoetes) can spend several years in freshwater burrowed within soft sediments, inhibiting their detection and assessment. Here, we present a qPCR assay based on the detection of environmental DNA (eDNA) to identify the presence of ammocoetes burrowed in the sediment. We present an extensively validated method that ensured both species‐specificity of the assay as well as the capacity to detect ammocoetes when abundances are low. Experiments on burrowing activity suggested that most of the DNA released into the sediment occurs during burrowing. Overall, we demonstrate this new molecular‐based tool is an efficient and effective complement to traditional monitoring activities targeting larval stages of sea lampreys.

Review of Current Issues and Management Strategies of Microplastics in Groundwater Environments

Microplastic contamination has become widespread in natural ecosystems around the globe as a result of the tremendous rise in plastic production over the last 70 years. However, microplastic pollution in marine and riverine habitats has received more attention than that of terrestrial environments or even groundwater. This manuscript reviews the current issues, potential occurrences, and sources of the emerging problem of microplastic contamination in groundwater systems. The most prevalent types of plastic detected in groundwater are polyethylene and polyethylene terephthalate, and fibers and fragments represent the most commonly found shapes. The vertical transportation of microplastics in agricultural soils can affect groundwater aquifer systems, which is detrimental to those who use groundwater for drinking as well as to microorganisms present in the aquifers. Moreover, this review sheds light on the interlinkage between sustainable development goals and groundwater microplastic contamination issues as part of the strategies for the management of microplastic contamination in groundwater. Overall, this review reveals a lack of interest and a gap in knowledge regarding groundwater microplastic pollution and highlights future perspectives for research in this area.

Diversity, distribution and extinction risk of native freshwater fishes of South Africa.

Extinction risk for 101 valid species and 18 unique genetic lineages of native freshwater fishes of South Africa was assessed in 2016 following the IUCN Red List criteria. An additional five species (three new species that were described and two species that were revalidated subsequent to the 2016 assessments) were assessed in the present study. A synthesis of the outcome of the assessments of the 106 valid species and 18 genetic lineages indicates that 45 (36%) of South Africa's freshwater fish taxa are threatened (7 Critically Endangered, 25 Endangered, 13 Vulnerable). Of the remaining taxa, 17 (14%) are listed as Near Threatened, 57 (46%) are Least Concern and five (4%) are Data Deficient. More than 60% of the endemic taxa are threatened. The Cape Fold Ecoregion has the highest proportion of threatened taxa (67%) due to the existence of a unique assemblage of narrow-range endemic species. Galaxias and Pseudobarbus have the highest number of highly threatened taxa as most of the species and lineages in these genera are classified as either CR or EN. Major threats to the native freshwater fishes of the country are invasive fish species, deterioration of water quality, impoundments and excessive water abstraction, land use changes and modification of riverine habitats. Immediate conservation efforts should focus on securing remnant populations of highly threatened taxa and preventing deterioration in threat status, because recovery is rare. Accurate delimitation of species boundaries, mapping their distribution ranges, improved knowledge of pressures and long-term monitoring of population trends need to be prioritised to generate credible data for the 2026 IUCN threat status assessments and designation of important fish areas as part of the National Freshwater Ecosystem Priority Areas (NFEPA) initiative.

Bioavailability of legacy and current-use pesticides in juvenile Chinook salmon habitat of the Sacramento River watershed: Importance of sediment characteristics and extraction techniques

The Sacramento River watershed, California, provides important rearing and migratory habitat for several species of conservation concern. Studies have suggested significant benefits for juvenile fish rearing in floodplain habitats of the watershed compared to the mainstem Sacramento River. However, the potential for contaminant exposure in each of these two habitats is poorly understood. Consequently, the present study aimed to determine the distribution and occurrence of bioavailable pesticides within two known salmon habitats using a suite of approaches including exhaustive chemical extraction, single-point Tenax extraction (SPTE) and ex situ passive sampling. Sediment samples were collected from sites within both habitats twice annually in 2019 and 2020, with inundation of the floodplain and high flows for both areas in 2019 and low flow conditions observed in 2020. Sediment characteristics including total organic carbon, black carbon and particle size distribution were determined to elucidate the influence of physical characteristics on pesticide distribution. Using exhaustive extractions, significantly greater sediment concentrations of organochlorines were observed in the floodplain compared to the Sacramento River in both years, with bioaccessible organochlorine concentrations also significantly greater in the floodplain (ANOVA, p < 0.05). Using both SPTEs and exhaustive extractions, significantly fewer pesticides were detected across both sites under low flow conditions as compared to high flow conditions (Poisson regression, p < 0.05). Sediment characteristics including percent fines and black carbon had significant positive relationships with total and bioaccessible pyrethroid and organochlorine concentrations. Fewer analytes were detected using low-density polyethylene (LDPE) passive samplers as compared to SPTEs, suggesting greater sensitivity of the Tenax technique for bioavailability assessments. These findings suggest that threatened juvenile fish populations rearing on the floodplain may have greater exposure to organochlorines than fish inhabiting adjacent riverine habitats, and that pesticide exposure of resident biota may be exacerbated during high-flow conditions.

Pesticide residues in juvenile Chinook salmon and prey items of the Sacramento River watershed, California – A comparison of riverine and floodplain habitats

Juvenile Chinook salmon (Oncorhynchus tshawytscha) of the Sacramento River system encounter many anthropogenically-induced stressors while rearing and migrating to the Pacific Ocean. Located in a prominent agricultural region, the watershed serves as a source of notable contaminants including pesticides. Salmon rearing in riverine and floodplain areas are potentially exposed to these compounds via dietary exposure, which can vary based on selected food webs. Previous studies have suggested that juvenile Chinook salmon rearing in riverine and floodplain environments of the Sacramento River watershed are characterized by different dietary preferences, with potential for contrasting pesticide exposure between habitats. To examine the potential for pesticide exposure, juvenile Chinook salmon and known dietary items were collected in the mainstem Sacramento River and an adjacent floodplain, the Yolo Bypass, in 2019 and 2020, and analyzed for 33 pesticides, including degradates and isomers. Organochlorine pesticides including the DDX group (p,p’-DDT, p,p’-DDD and p,p’-DDE) were prevalent in all examined biota. There was a significantly greater number of total pesticide detections across all classes in zooplankton compared to macroinvertebrates, coupled with higher bifenthrin concentrations in zooplankton across regions and years, which may indicate different exposure potential depending on fish dietary preferences. Detection frequencies and concentrations of organochlorines were higher in prey items during flooding than in drought conditions, suggesting resuspension of legacy compounds. Significantly higher concentrations of organochlorines were recorded in floodplain rearing fish compared to the Sacramento River. These findings suggest that within these habitats, juvenile Chinook salmon feeding primarily on zooplankton within the water column may be exposed to a greater range of pesticides than those feeding on benthic macroinvertebrates, and that the benefits of floodplain rearing may come at a cost of increased organochlorine exposure.

Dietary fatty acid profiles shape crayfish biosynthesis and performance: Implications for riverine food webs

Abstract Alteration of riverine flows can modify the structure and function of ecosystems, changing energy pathways and patterns of micronutrient transfer between trophic levels. Fatty acids (FAs) commonly are used to evaluate food quality, since some FAs required for somatic growth and physiological functions in animals must be obtained from their diet. FAs also are used in food‐web studies as biotracers as a consequence of their constrained metabolic biosynthesis by animals. However, their utility may be confounded by selective retention or modification of dietary FAs by consumers. We conducted a 70‐day feeding trial to compare growth and survival of an abundant and widespread mesoconsumer (Cherax destructor, the common yabby or crayfish) fed three contrasting diets: a poor‐quality detritus‐based diet; a high protein invertebrate diet; and a high‐quality commercial aquaculture pellet. Fatty acid profiles were obtained for each dietary treatment and contrasted with crayfish FA profiles at the end of the experiment to examine patterns of FA retention and integration. We also collected wild crayfish from floodplain wetland and river habitats, and obtained FA profiles from their stomach contents and body tissue to compare with experimental crayfish. Experimental crayfish fed high‐quality commercial pellets doubled in mass during the 70‐day assay, invertebrate fed crayfish growth was intermediate, and growth of crayfish fed detritus was negligible. Fatty acid profiles of crayfish fed our three contrasting diets differed significantly at the end of the experiment. Proportions of the polyunsaturated omega‐6 FA linoleic acid (LIN, 18:2ω6) in crayfish followed the same inequality observed in growth and diets: pellets &gt; invertebrates &gt; detritus. Pellet‐fed crayfish preferentially assimilated greater proportions of FAs 20:4ω6 (ARA), 20:5ω3 (EPA) 18:1ω9 (OA) and 16:1ω7 (POA) into their tissue. Fatty acid profiles of floodplain crayfish differed to profiles of riverine crayfish, and floodplain crayfish had higher proportions of essential FAs ARA and LIN in their tissues. Fatty acid biosynthesis by crayfish was best described by a hypothesis of FA allostasis rather than homeostasis; in this, FA profiles of crayfish were shaped by their diet, and selective integration and modification of high‐quality FAs from basal resources rich in these micronutrients led to higher proportions in crayfish tissues. Here we present evidence for the conversion of shorter‐chain essential FAs by freshwater crayfish to compensate for a lack of long‐chain FAs in their diet. We provide a necessary step for improving our understanding of micronutrient dynamics and the transfer of essential molecules between trophic levels in lowland river food webs. Floodplain habitats are known to provide higher‐quality basal food resources for mesoconsumers than riverine habitats, and here we identify one mechanism by which that may be extended to subsequent trophic levels.

A new index to quantify longitudinal river fragmentation: Conservation and management implications

The proliferation of river infrastructure projects has altered aquatic longitudinal connectivity, posing a growing threat to riverine biodiversity and ecosystem processes worldwide. Effective methods to quantify loss of river connectivity across spatiotemporal scales and in data-limited landscapes are important to understand and inform basin-wide conservation and development planning. Here we introduce a Catchment Area-based Fragmentation Index (CAFI) and its derivative, the Catchment Area- and Rainfall-based Fragmentation Index (CARFI) as new metrics to quantify river fragmentation. These indices use catchment area as a proxy for riverine habitat availability, avoiding the drawbacks of existing metrics that rely on river length and associated derivatives. CAFI/CARFI can be computed across spatiotemporal scales, incorporate barrier passability values, assesses the cumulative impact of multiple barriers, and be applied even in data-limited environments.We first applied CAFI and CARFI to a simulated network to illustrate their properties with respect to the number and location of barriers and compared these results to the widely applied Dendritic Connectivity Index (DCI). While all indices varied with barrier addition, CAFI and CARFI were more sensitive to both barrier number and location. Next, we illustrated the utility of CAFI and CARFI through case studies in two contrasting settings: the Klamath River in California, where dam building has ceased (and dam removals are being considered) and the Netravathi River in India, where dam building is ongoing, with 65 dams proposed for future development. Results indicate that CAFI and CARFI can effectively quantify trends in fragmentation across spatial scales and temporal scenarios of dam development (i.e. descriptive applications) and can aid the prioritization of sites for dam removal, restoration, or conservation (i.e. prescriptive applications). Overall, these indices can quantify the impacts of individual dams and assess a range of development scenarios to inform basin-wide conservation and development planning.

Variability in foodscapes and fish growth across a habitat mosaic: Implications for management and ecosystem restoration

Riverine ecosystems in their natural state are complex mosaics of habitats whose conditions vary across space and time as landscape features filter prevailing hydrologic forcing. Yet, through anthropogenic alteration many large river systems have become simplified through the construction of levees and dams that reduce lateral connectivity and flow variability. The extent to which shifts in habitat mosaics create conditions that support different trophic responses that manifest in differences in fish growth across the landscape remains largely untested. This is primarily due to limitations in linking habitat features, dynamic physical processes, and trophic transfer of energy to higher taxa at the landscape scale. Here, we conducted large-scale enclosure experiments across varying habitats on a fluvial floodplain as a model system to measure factors that influence habitat-specific growth rates in multiple Chinook Salmon (Oncorhynchus tshawytscha) stocks important to fisheries and of conservation concern. Using an ecosystem approach, we reveal that landscape context, water residence time, and habitat type (agricultural, wetland, river channel) result in different hot-spots of primary and secondary food production. This variation in the aquatic foodscape resulted in significant variation in salmon growth rates and ultimate size and morphology across the landscape. Floodplain habitats generally exhibited higher water residence times as highlighted by higher specific conductance, salinity, and chlorophyll-a values. Pelagic invertebrate abundance was 10 to 100 times more abundant in the off-channel habitats compared to the river channels. The average daily growth rates of the juvenile Chinook Salmon ranged from 0.15 mm day−1 and 0.01 g day−1 in the riverine habitat to 0.55 mm day−1 and 0.07 g day−1 in the off-channel habitat. These data were used to build mixed effects models that showed the influence of chlorophyll-a concentration, water temperature and pelagic invertebrate composition on fish growth across locations throughout the experiment. As landscapes become increasingly simplified there is increased risk of losing the mosaic of habitats necessary to achieve enhanced fish growth and phenotypically diverse and sustainable salmon populations. This in-situ experimental and modeling approach can be applied to other systems to develop ecosystem indicators such as habitat-specific fish growth rates to manage landscapes and processes to support resilient fish populations.

Kansyore Fisher-Hunter-Gatherers Abandoned the Northeastern Lake Victoria Shoreline during an Arid Period in the Middle Holocene: A Reconsideration of Dates from Western Kenya with New Radiometric and Faunal Evidence from the Namundiri A Shell Midden, Eastern Uganda

Abstract Kansyore pottery-using groups of the northeastern Lake Victoria Basin represent one of only a few examples of ‘complex’ hunter-gatherers in Africa. Archaeologists link evidence of specialized fishing, a seasonal land-use cycle between lake and riverine sites, and intensive investment in ceramic production to behavioral complexity after 9 thousand years ago (ka). However, a gap in the Kansyore radiocarbon record of the region between ~7 and 4.4 cal ka limits explanations of when and why social and economic changes occurred. This study provides the first evidence of lakeshore occupation during this temporal break at the only well-studied Kansyore site in eastern Uganda, Namundiri A. Within the context of other sites in nearby western Kenya, radiometric and faunal data from the site indicate a move from the lake to a greater reliance on riverine habitats with middle Holocene aridity ~5–4 cal ka and the arrival of food producers to the region after ~3 cal ka.

STAND STRUCTURE AND PRODUCTIVITY OF THE FIREFLY RIVERINE MANGROVE HABITAT AT THREE RIVERS IN PENINSULAR MALAYSIA

Studies on floristic composition, forest structure and tree diversity are important to determine the pattern of stand structure, current status and floristic variation of firefly riverine mangrove habitats in Peninsular Malaysia. Thus, this study was conducted in three rivers, namely Sungai Chukai, Terengganu, Sungai Rembau-Linggi, Negeri Sembilan and Sungai Sepetang, Taiping, Perak. A total of 647,362 and 514 tree stands measuring 1 cm diameter and above were enumerated in 0.5 ha plots at the three sites, respectively. A total of 40 species were recorded in Sungai Chukai, 17 species in Sungai Rembau-Linggi and 14 species in Sungai Sepetang. The 0.5, 0.35 and 0.40 ha of each study site, respectively, were capable of capturing all the species in the mangrove forest. Rhizophoraceae family was found to have the highest density and basal area in all the study sites. The highest species density for Sungai Chukai, Sungai Rembau-Linggi and Sungai Sepetang was R. apiculata with a density of 262 ind ha-1, 120 ind ha-1 and 516 ind ha-1, respectively. The major contributor of total basal area at Sungai Chukai, Sungai Rembau-Linggi and Sungai Sepetang were X. granatum (5.5583 m2 ha-1) and R. apiculata with 10.6833 m2 ha-1 and 11.7491 m2 ha-1, respectively. Diversity and species richness were higher at Sungai Chukai (H’= 2.82, R’= 6.03) compared to Sungai Rembau-Linggi (H’=2.09, R’= 2.72) and Sungai Sepetang (H’=1.43, R’= 2.08). The highest total biomass of mangrove forest was at Sungai Rembau-Linggi with 321.21 t ha-1 followed by Sungai Sepetang (247.41 t ha-1) and Sungai Chukai (210.36 t ha-1). These results indicated that the current status of community structure and vegetation varied among the rivers. The study can act as a guideline in the management plan of firefly habitats, which also affect firefly distribution along the three rivers in Peninsular Malaysia.

Study on usage of Land and changes in Ecology in Babile Elephant Sanctuary, Eastern Ethiopia

The focus of this paper is to investigate how the land covers in Eastern Ethiopia's Babile Elephant Sanctuary (BES). The spatiotemporal patterns of land-cover changes involved using remote sensing, geographic information systems, and questionnaires. Researchers used the Landsat images acquired in 1972, 2000, and 2021 were used. The result revealed that bushland and agricultural land areas expanded highest over the study period (1972–2021) at the expense of natural forests. With an average annual loss rate of 8343.12 ha, riverine forests and woods lost a substantial amount of land cover. The woodland and riverine forest cover decreased steadily from 59.85 and 20.56% in 1972 to 30.37 and 3.13% in 2021.From 1972, the coverage of bushland, agricultural land, bare land, and settlement increased to 17.57, 1.75, 0.23, and 0.04%, respectively, to the year 2021, when it occupied 34.68, 22.30, 4.95, and 4.57%, respectively, of the total land area. Several bushland areas in the sanctuary while data collected for this study, with likely impacts were observed (such as tree-cutting) on the forest and riverine habitat. As a result, there was currently a greater area covered by wilderness patches (i.e., 34.68 % in 2021). The result showed that the increasing agricultural land and settlements become a threat to the ecological integrity of elephant habitats, leading to habitat fragmentation and human encroachment on elephant habitats, and high pressure and competition over resources. Based on the study, the interpretation drawn is that, BES is necessary to build gaps in knowledge for conservationists to design plans for the restoration of habitats and the species by lowering the impact on land cover change, immediate action, and restoring mechanisms to conserve biodiversity and associated ecosystem services in the area.