1
|
Wang F, Wang H, Dong W, Yu X, Zuo Z, Lu X, Zhao Z, Jiang J, Zhang X. Enhanced multi-metals stabilization: Synergistic insights from hydroxyapatite and peroxide dosing strategies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172159. [PMID: 38575032 DOI: 10.1016/j.scitotenv.2024.172159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 02/27/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
Sediment contamination by heavy metals is a pressing environmental concern. While in situ metal stabilization techniques have shown promise, a great challenge remains in the simultaneous immobilization of multi-metals co-existing in contaminated sediments. This study aims to address this challenge by developing a practical method for stabilizing multi-metals by hydroxyapatite and calcium peroxide (HAP/CaO2) dosing strategies. Results showed that dosing 15.12 g of HAP/CaO2 at a ratio of 3:1 effectively transformed labile metals into stable fractions, reaching reaction kinetic equilibrium within one month with a pseudo-second-order kinetic (R2 > 0.98). The stable fractions of Nickel (Ni), Chromium (Cr), and lead (Pb) increased by approximately 16.9 %, 26.7 %, and 21.9 %, respectively, reducing heavy metal mobility and ensuring leachable concentrations complied with the stringent environmental Class I standard. Mechanistic analysis indicated that HAP played a crucial role in Pb stabilization, exhibiting a high rate of 0.0176 d-1, while Cr and Ni stabilization primarily occurred through the formation of hydroxide precipitates, as well as the slowly elevated pH (>8.5). Importantly, the proposed strategy poses a minimal environmental risk to benthic organisms exhibits almost negligible toxicity towards Vibrio fischeri and the Chironomus riparius, and saves about 71 % of costs compared to kaolinite. These advantages suggest the feasibility of HAP/CaO2 dosing strategies in multi-metal stabilization in contaminated sediments.
Collapse
Affiliation(s)
- Feng Wang
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; School of Economics and Management, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China
| | - Hongjie Wang
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Wenyi Dong
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Xiaohong Yu
- School of Economics and Management, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China
| | - Zhiqiang Zuo
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - Xi Lu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zilong Zhao
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China.
| | - Jiahong Jiang
- New York University, New York, NY 10012, United States
| | - Xiaoyu Zhang
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China
| |
Collapse
|
2
|
Voysey MD, de Bruyn PJN, Davies AB. Are hippos Africa's most influential megaherbivore? A review of ecosystem engineering by the semi-aquatic common hippopotamus. Biol Rev Camb Philos Soc 2023; 98:1509-1529. [PMID: 37095627 DOI: 10.1111/brv.12960] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/26/2023]
Abstract
Megaherbivores perform vital ecosystem engineering roles, and have their last remaining stronghold in Africa. Of Africa's remaining megaherbivores, the common hippopotamus (Hippopotamus amphibius) has received the least scientific and conservation attention, despite how influential their ecosystem engineering activities appear to be. Given the potentially crucial ecosystem engineering influence of hippos, as well as mounting conservation concerns threatening their long-term persistence, a review of the evidence for hippos being ecosystem engineers, and the effects of their engineering, is both timely and necessary. In this review, we assess, (i) aspects of hippo biology that underlie their unique ecosystem engineering potential; (ii) evaluate hippo ecological impacts in terrestrial and aquatic environments; (iii) compare the ecosystem engineering influence of hippos to other extant African megaherbivores; (iv) evaluate factors most critical to hippo conservation and ecosystem engineering; and (v) highlight future research directions and challenges that may yield new insights into the ecological role of hippos, and of megaherbivores more broadly. We find that a variety of key life-history traits determine the hippo's unique influence, including their semi-aquatic lifestyle, large body size, specialised gut anatomy, muzzle structure, small and partially webbed feet, and highly gregarious nature. On land, hippos create grazing lawns that contain distinct plant communities and alter fire spatial extent, which shapes woody plant demographics and might assist in maintaining fire-sensitive riverine vegetation. In water, hippos deposit nutrient-rich dung, stimulating aquatic food chains and altering water chemistry and quality, impacting a host of different organisms. Hippo trampling and wallowing alters geomorphological processes, widening riverbanks, creating new river channels, and forming gullies along well-utilised hippo paths. Taken together, we propose that these myriad impacts combine to make hippos Africa's most influential megaherbivore, specifically because of the high diversity and intensity of their ecological impacts compared with other megaherbivores, and because of their unique capacity to transfer nutrients across ecosystem boundaries, enriching both terrestrial and aquatic ecosystems. Nonetheless, water pollution and extraction for agriculture and industry, erratic rainfall patterns and human-hippo conflict, threaten hippo ecosystem engineering and persistence. Therefore, we encourage greater consideration of the unique role of hippos as ecosystem engineers when considering the functional importance of megafauna in African ecosystems, and increased attention to declining hippo habitat and populations, which if unchecked could change the way in which many African ecosystems function.
Collapse
Affiliation(s)
- Michael D Voysey
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
| | - P J Nico de Bruyn
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Andrew B Davies
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
| |
Collapse
|
3
|
Hee YY, Weston K, Suratman S, Akhir MF, Latif MT, Valliyodan S. Biogeochemical and physical drivers of hypoxia in a tropical embayment (Brunei Bay). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:65351-65363. [PMID: 37081368 DOI: 10.1007/s11356-023-26948-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 04/06/2023] [Indexed: 05/03/2023]
Abstract
Dissolved oxygen is an ecologically critical variable with the prevalence of hypoxia one of the key global anthropogenic issues. A study was carried out to understand the causes of low dissolved oxygen in Brunei Bay, northwest Borneo. Hypoxia was widespread in bottom waters in the monsoonal dry season with dissolved oxygen < 2 mg/L throughout the coastal zone. This was a result of riverine nutrient input primarily from the Padas river driving excess primary production and its subsequent sinking into stratified bottom water where its decomposition consumed oxygen. Despite higher riverine nutrient input in the wet season hypoxia was less extensive due to the combination of turbidity reducing coastal primary production, the intrusion of oxygen-rich water from the South China Sea into offshore bottom layer waters and horizontal flushing increase advection of phytoplankton biomass out of the bay. Future investigation of hypoxia in shallow tropical regions therefore needs to consider the role of monsoonal season.
Collapse
Affiliation(s)
- Yet Yin Hee
- Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
| | - Keith Weston
- Independent Environmental Consultant, Norwich, Norfolk, UK
| | - Suhaimi Suratman
- Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Mohd Fadzil Akhir
- Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Mohd Talib Latif
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
| | | |
Collapse
|
4
|
Pritchard AJ, Fefferman NH. Trade-offs in resource access and health by avoidance of self-fouling, motivated via disgust. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2022.110225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
5
|
M K VS, Joseph S, P S A, Ghermandi A, Kumar A. A coastal Ramsar site on transition to hypoxia and tracking pollution sources: a case study of south-west coast of India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 195:45. [PMID: 36305948 DOI: 10.1007/s10661-022-10602-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Coastal lakes and estuaries are considered economic drivers for coastal communities by delivering invaluable economic and ecosystem services. The coastal ecosystems are facing recurrent hypoxia events (dissolved oxygen; DO < 2.0 mg L-1) and are emerging as a major threat to ecosystem structure and functioning. The Ashtamudi Lake, (area = 56 km2), is one of the Ramsar sites in the State of Kerala and located on the SW coast of India. The waterways are extensively used for backwater tourism and for fishery activities. This paper discusses the spatio-temporal variation of water quality attributes with emphasis on hypoxia during non-monsoon and monsoon seasons. The extent of hypoxia on fishery diversity was discussed. The Southern Zone, adjacent to the urban area, shows the hypoxic condition with higher concentration of BOD, NO3-N, and NH4-N. The hypoxic condition is largely limited to the Southern Zone in both seasons. The occurrence of low DO in the lake is highly related to salinity and organic load in the lake system. The tracking of pollution sources in the lake system was also done through identification of pollution potential zones and found that catchments adjacent to Southern and Western Zones (urban regions) are the major source of pollution. The study suggests that hypoxia is chiefly attributed to anthropogenic interventions in the form of discharge of wastes into the lake causing overloading of nutrients and organic effluents, decrease in the freshwater supply, the absence of proper freshwater mixing or dilution, and effluent discharge from nearby urban centers.
Collapse
Affiliation(s)
- Vishnu Sagar M K
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581
| | - Sabu Joseph
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581.
| | - Arunkumar P S
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581
| | - Andrea Ghermandi
- Department of Natural Resources and Environmental Management, University of Haifa, Haifa, Israel
| | - Amit Kumar
- School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China
| |
Collapse
|
6
|
Sun C, Wang S, Wang H, Hu X, Yang F, Tang M, Zhang M, Zhong J. Internal nitrogen and phosphorus loading in a seasonally stratified reservoir: Implications for eutrophication management of deep-water ecosystems. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115681. [PMID: 35816961 DOI: 10.1016/j.jenvman.2022.115681] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/21/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
Water eutrophication is a serious global issue because of excess external and internal nutrient inputs. Understanding the intensity and contribution of internal nitrogen (N) and phosphorus (P) loading in deep-water ecosystems is of great significance for water body eutrophication management. In this study, we combined intact sediment core incubation, high-resolution peeper (HR-Peeper) sampling, and analysis of N and P forms and other environmental factors in the water column and sediments to evaluate the contributions of internal N and P loading to water eutrophication by N and P fluxes across the sediment-water interface (SWI) of the Panjiakou Reservoir (PJKR), a deep-water ecosystem where eutrophication threatens the security of the local drinking water supply in North China. The results indicated that the PJKR showed obvious thermal and dissolved oxygen (DO) stratification in the warm seasons and full mixing in the cold seasons. The mean DO concentration was 9.9 and 3.55 mg/L in the epilimnion and hypolimnion, respectively, in warm seasons and 10.7 mg/L in cold seasons. The sediment acted as a source of soluble reactive phosphorus (SRP), NH4+-N, and NO2--N and a sink of NO3--N. The SRP fluxes were 5.28 ± 4.34 and 2.30 ± 1.93 mg m-2·d-1 in warm and cold seasons, respectively, and the dissolved inorganic nitrogen (DIN) fluxes were -0.66 ± 47.84 and 44.04 ± 84.05 mg m-2·d-1. Seasonal hypoxia accelerated the release of P rather than N from the sediments in warm seasons, which came mainly from Fe-P and Org-P under anoxic conditions. The strong negative NO3--N flux (diffusion from the water column to the sediment) implied an intensive denitrification process at the SWI, which can counteract the release flux of NH4+-N and NO2--N, resulting in the sediment acting as a weak dissolved inorganic nitrogen (DIN) source for the overlying water. We also found that internal N loading accounted for only ∼9% of the total N loading, while internal P loading accounted for 43% of the total P loading of the reservoir. Our results highlight that efforts to manage the internal loading of deep-water ecosystems should focus on P and seasonal hypoxia.
Collapse
Affiliation(s)
- Chuanzhe Sun
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shaoming Wang
- Bureau of Luanhe Diversion Project, Haihe Water Conservancy Commission, Ministry of Water Resources, Qianxi 064309, PR China
| | - Hongwei Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xiaokang Hu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Fanyan Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, PR China
| | - Mengyao Tang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Min Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jicheng Zhong
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
| |
Collapse
|
7
|
Inundation area drives hippo group aggregation and dispersal in a seasonal floodplain system. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00286-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
8
|
Masese FO, Fuss T, Bistarelli LT, Buchen-Tschiskale C, Singer G. Large herbivorous wildlife and livestock differentially influence the relative importance of different sources of energy for riverine food webs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 828:154452. [PMID: 35278569 DOI: 10.1016/j.scitotenv.2022.154452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 03/05/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
In many regions of the world, large populations of native wildlife have declined or been replaced by livestock grazing areas and farmlands, with consequences for terrestrial-aquatic ecosystem connectivity and trophic resources supporting food webs in aquatic ecosystems. The river continuum concept (RCC) and the riverine productivity model (RPM) predict a shift of energy supplying aquatic food webs along rivers: from terrestrial inputs in low-order streams to autochthonous production in mid-sized rivers. In Afromontane-savanna landscapes, the shifting numbers of large mammalian wildlife present a physical continuum whose ecological implications for rivers is not clearly understood. Here, we studied the influence of replacing large wildlife (mainly hippos) with livestock on the fractional contribution of C3 vegetation, C4 grasses and periphyton on macroinvertebrates in the Mara River, which is an African montane-savanna river known to receive large subsidy fluxes of terrestrial organic matter and nutrients mediated by large mammalian herbivores (LMH), both wildlife and livestock, in its middle and lower reaches. Using stable carbon (δ13C) and nitrogen (δ15N) isotopes, we identified spatial patterns in the fractional contribution of allochthonous organic matter from C3 and C4 plants (woody vegetation and grasses, respectively) and autochthonous energy from periphyton for macroinvertebrates at various sites of the Mara River and its tributaries. Potential energy sources and invertebrates were sampled at 80 sites spanning stream orders 1 to 7, various catchment land uses (forest, agriculture and grasslands) and different loading rates of organic matter and nutrients by LMH (livestock and wildlife, i.e., hippopotamus). The fractional contribution of different sources of energy for macroinvertebrates along the river did not follow predictions of the RCC and RPM. First, the fractional contribution of C3 and C4 carbon was not related to river order or location along the fluvial continuum but to the loading of organic matter (dung) by both wildlife and livestock. Notably, C4 carbon was important for macroinvertebrates even in large river sections inhabited by hippos. Second, even in small 1st -3rd order forested streams, periphyton was a major source of energy for macroinvertebrates, and this was fostered by livestock inputs fuelling aquatic primary production throughout the river network. Importantly, our results show that replacing wildlife (hippos) with livestock shifts river systems towards greater reliance on autochthonous sources of energy through an algae-grazer pathway as opposed to reliance on allochthonous inputs of C4 carbon through a detrital pathway.
Collapse
Affiliation(s)
- Frank O Masese
- University of Eldoret, Department of Fisheries and Aquatic Science, P.O. Box 1125-30100, Eldoret, Kenya; Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
| | - Thomas Fuss
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Lukas Thuile Bistarelli
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Caroline Buchen-Tschiskale
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116 Braunschweig, Germany; Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straβe 84, 15374 Müncheberg, Germany
| | - Gabriel Singer
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany; Department of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| |
Collapse
|
9
|
|
10
|
Hippopotamus population trends in Ndumo Game Reserve, South Africa, from 1951 to 2021. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
11
|
Dutton CL, Subalusky AL, Sanchez A, Estrela S, Lu N, Hamilton SK, Njoroge L, Rosi EJ, Post DM. The meta-gut: community coalescence of animal gut and environmental microbiomes. Sci Rep 2021; 11:23117. [PMID: 34848778 PMCID: PMC8633035 DOI: 10.1038/s41598-021-02349-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/08/2021] [Indexed: 01/04/2023] Open
Abstract
All animals carry specialized microbiomes, and their gut microbiota are continuously released into the environment through excretion of waste. Here we propose the meta-gut as a novel conceptual framework that addresses the ability of the gut microbiome released from an animal to function outside the host and alter biogeochemical processes mediated by microbes. We demonstrate this dynamic in the hippopotamus (hippo) and the pools they inhabit. We used natural field gradients and experimental approaches to examine fecal and pool water microbial communities and aquatic biogeochemistry across a range of hippo inputs. Sequencing using 16S RNA methods revealed community coalescence between hippo gut microbiomes and the active microbial communities in hippo pools that received high inputs of hippo feces. The shared microbiome between the hippo gut and the waters into which they excrete constitutes a meta-gut system that could influence the biogeochemistry of recipient ecosystems and provide a reservoir of gut microbiomes that could influence other hosts. We propose that meta-gut dynamics may also occur where other animal species congregate in high densities, particularly in aquatic environments.
Collapse
Affiliation(s)
- Christopher L Dutton
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA.
- Department of Biology, University of Florida, Gainesville, FL, USA.
| | - Amanda L Subalusky
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Alvaro Sanchez
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Sylvie Estrela
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Nanxi Lu
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Stephen K Hamilton
- W.K. Kellogg Biological Station and Department of Integrative Biology, Michigan State University, Hickory Corners, MI, USA
- Cary Institute of Ecosystem Studies, Millbrook, NY, USA
| | | | - Emma J Rosi
- Cary Institute of Ecosystem Studies, Millbrook, NY, USA
| | - David M Post
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect St., New Haven, CT, 06511, USA
| |
Collapse
|
12
|
Nakangu NF, Masese FO, Barasa JE, Matolla GK, Riziki JW, Mbalassa M. Influence of the changing environment on food composition and condition factor in Labeo victorianus (Boulenger, 1901) in rivers of Lake Victoria Basin, Kenya. AQUACULTURE AND FISHERIES 2021. [DOI: 10.1016/j.aaf.2021.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
13
|
Saboret G, Buckle DJ, King AJ, Douglas MM, Crook DA. Partial migration in diadromous fishes drives the allocation of subsidies across the freshwater-marine ecotone. ANIMAL MIGRATION 2021. [DOI: 10.1515/ami-2020-0108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Migratory animals can act as cross-boundary subsidies sustaining ecosystem functioning, such as diadromous fishes that migrate between fresh water and seawater and carry nutrients and energy across the freshwater-marine ecotone. Frequency and timing of migration are however highly variable within and among populations. We hypothesized that in catadromous fishes (i.e., diadromous fishes that grow in freshwater and spawn in the sea, such as eels), the import of subsidies by migratory juveniles could outweigh the export of subsidies by adults due to skipped spawning migration. We used the diamond mullet Planiliza ordensis, as a model species, and determined life-history traits using a combination of length-to-age data, acoustic telemetry and otolith (fish ear stone) microchemistry. We used a mass balance approach to model individual mass acquisition and allocation, and extended our model to other life-history strategies. Our results showed high intra-population variation of migratory behaviour in P. ordensis, with few individuals migrating every year to spawn. We estimated that an individual P. ordensis acted as a net 42.6g biomass subsidy in fresh water, representing a retention of more than 50% of the juvenile mass at freshwater entry. Our model predicts that skipped spawning is likely to alter the allocation of subsidies in diadromous species, highlighting the important effects of individual variation in migratory behaviour on fluxes of energy and nutrient at ecosystem scales. We encourage future studies to consider how variation in migratory behaviour is likely to affect the direction and magnitude of biomass fluxes across ecotone boundaries.
Collapse
Affiliation(s)
- Grégoire Saboret
- Research Institute for the Environment and Livelihoods , Charles Darwin University , Darwin , 0810, NT , Australia ; Master Biosciences, ENS de Lyon, Département de Biologie , 46 allée d’Italie, 69007 Lyon , France ; Department of Surface Waters, EAWAG, Center for Ecology, Evolution and Biogeochemistry , 6047 Kastanienbaum , Switzerland
| | - Duncan J. Buckle
- Research Institute for the Environment and Livelihoods , Charles Darwin University , Darwin , 0810, NT , Australia
| | - Alison J. King
- Research Institute for the Environment and Livelihoods , Charles Darwin University , Darwin , 0810, NT , Australia
- Centre for Freshwater Ecosystems , La Trobe University , Albury-Wodonga, 3690, New South Wales , Australia
| | - Michael M. Douglas
- Research Institute for the Environment and Livelihoods , Charles Darwin University , Darwin , 0810, NT , Australia
- School of Biological Sciences , The University of Western Australia , 6009, Western Australia , Australia
| | - David A. Crook
- Research Institute for the Environment and Livelihoods , Charles Darwin University , Darwin , 0810, NT , Australia
- Centre for Freshwater Ecosystems , La Trobe University , Albury-Wodonga, 3690, New South Wales , Australia
| |
Collapse
|
14
|
Iteba JO, Hein T, Singer GA, Masese FO. Livestock as vectors of organic matter and nutrient loading in aquatic ecosystems in African savannas. PLoS One 2021; 16:e0257076. [PMID: 34495982 PMCID: PMC8425544 DOI: 10.1371/journal.pone.0257076] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 08/23/2021] [Indexed: 11/19/2022] Open
Abstract
Populations of large wildlife have declined in many landscapes around the world, and have been replaced or displaced by livestock. The consequences of these changes on the transfer of organic matter (OM) and nutrients from terrestrial to aquatic ecosystems are not well understood. We used behavioural data, excretion and egestion rates and C: N: P stoichiometry of dung and urine of zebu cattle, to develop a metabolism-based estimate of loading rates of OM (dung), C, N and P into the Mara River, Kenya. We also directly measured the deposition of OM and urine by cattle into the river during watering. Per head, zebu cattle excrete and/or egest 25.6 g dry matter (DM, 99.6 g wet mass; metabolism) - 27.7 g DM (direct input) of OM, 16.0-21.8 g C, 5.9-9.6 g N, and 0.3-0.5 g P per day into the river. To replace loading rates OM of an individual hippopotamus by cattle, around 100 individuals will be needed, but much less for different elements. In parts of the investigated sub-catchments loading rates by cattle were equivalent to or higher than that of the hippopotamus. The patterns of increased suspended materials and nutrients as a result of livestock activity fit into historical findings on nutrients concentrations, dissolved organic carbon and other variables in agricultural and livestock areas in the Mara River basin. Changing these patterns of carbon and nutrient transport and cycling are having significant effects on the structure and functioning of both terrestrial and aquatic ecosystems.
Collapse
Affiliation(s)
- Jacob O. Iteba
- Department of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
- Department of Fisheries and Aquatic Sciences, University of Eldoret, Eldoret, Kenya
| | - Thomas Hein
- Department of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
- WasserCluster Lunz, Lunz am See, Austria
| | - Gabriel A. Singer
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Frank O. Masese
- Department of Fisheries and Aquatic Sciences, University of Eldoret, Eldoret, Kenya
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Aquatic Science and Ecosystems Group, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| |
Collapse
|
15
|
Li N, Huang T, Chang Z, Li K. Effects of benthic hydraulics on sediment oxygen demand in a canyon-shaped deep drinking water reservoir: Experimental and modeling study. J Environ Sci (China) 2021; 102:226-234. [PMID: 33637247 DOI: 10.1016/j.jes.2020.09.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 06/12/2023]
Abstract
Sediment oxygen demand (SOD) is a major contributor to hypolimnetic oxygen depletion and the release of internal nutrient loading. By measuring the SOD in experimental chambers using in both dissolved oxygen (DO) depletion and diffusional oxygen transfer methods, a model of SOD for a sediment bed with water current-induced turbulence was presented. An experimental study was also performed using near-sediment vertical DO profiles and correlated hydraulic parameters stimulated using a computational fluid dynamics model to determine how turbulences and DO concentrations in the overlying water affects SOD and diffusive boundary layer thickness. The dependence of the oxygen transfer coefficient and diffusive boundary layer on hydraulic parameters was quantified, and the SOD was expressed as a function of the shear velocity and the bulk DO concentrations. Theoretical predictions were validated using microelectrode measurements in a series of laboratory experiments. This study found that flow over the sediment surface caused an increase in SOD, attributed to enhanced sediment oxygen uptake and reduced substances fluxes, i.e., for a constant maximum biological oxygen consumption rate, an increased current over the sediment could increase the SOD by 4.5 times compared to stagnant water. These results highlight the importance of considering current-induced SOD increases when designing and implementing aeration/artificial mixing strategies.
Collapse
Affiliation(s)
- Nan Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China..
| | - Zhiying Chang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Kai Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| |
Collapse
|
16
|
Fritsch CJ, Downs CT. Evaluation of low‐cost consumer‐grade
UAVs
for conducting comprehensive high‐frequency population censuses of hippopotamus populations. CONSERVATION SCIENCE AND PRACTICE 2020. [DOI: 10.1111/csp2.281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Camille J. Fritsch
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
| | - Colleen T. Downs
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
| |
Collapse
|
17
|
Utete B. A review of some aspects of the ecology, population trends, threats and conservation strategies for the common hippopotamus, Hippopotamus amphibius L, in Zimbabwe. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2020.1779613] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Beaven Utete
- Department of Wildlife Ecology and Conservation, Chinhoyi University of Technology, Chinhoyi, Zimbabwe
| |
Collapse
|
18
|
Fatty acid analyses provide novel insights on hippo defecation and consequences for aquatic food webs. Sci Rep 2020; 10:12039. [PMID: 32694566 PMCID: PMC7374712 DOI: 10.1038/s41598-020-68369-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/19/2020] [Indexed: 11/23/2022] Open
Abstract
By defecating grasses into aquatic systems at massive scales and intensities, hippos can initiate complex changes to aquatic ecosystems. However, consequent effects on food webs are not well understood, particularly regarding shifts in basal resource contributions to consumer diets and their physiological condition. Here, we use fatty acid analysis to show that dense hippo aggregations and high dung loading are associated with (1) alterations to basal resource pools, (2) reduced quality of sediment organic matter and (3) increases in terrestrial and bacterial biomarker levels, but declines in those of diatoms in estuarine secondary consumers. While hippo defecation can increase boundary permeability between terrestrial and aquatic systems, our findings indicate that this may lead to a shift from a microphytobenthic food web base to one with increasing bacterial contributions to higher consumers. Our findings expand understanding of the mechanisms by which an iconic African megaherbivore indirectly structures aquatic ecosystems.
Collapse
|
19
|
|
20
|
Prinsloo AS, Pillay D, O'Riain MJ. Multiscale drivers of hippopotamus distribution in the St Lucia Estuary, South Africa. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2020.1717377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Alexa S Prinsloo
- Marine Research Institute, Department of Biological Sciences, University of Cape Town, South Africa
| | - Deena Pillay
- Marine Research Institute, Department of Biological Sciences, University of Cape Town, South Africa
| | - M Justin O'Riain
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, South Africa
| |
Collapse
|
21
|
Masese FO, Kiplagat MJ, González-Quijano CR, Subalusky AL, Dutton CL, Post DM, Singer GA. Hippopotamus are distinct from domestic livestock in their resource subsidies to and effects on aquatic ecosystems. Proc Biol Sci 2020; 287:20193000. [PMID: 32345142 PMCID: PMC7282896 DOI: 10.1098/rspb.2019.3000] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/31/2020] [Indexed: 12/31/2022] Open
Abstract
In many regions of the world, populations of large wildlife have been displaced by livestock, and this may change the functioning of aquatic ecosystems owing to significant differences in the quantity and quality of their dung. We developed a model for estimating loading rates of organic matter (dung) by cattle for comparison with estimated rates for hippopotamus in the Mara River, Kenya. We then conducted a replicated mesocosm experiment to measure ecosystem effects of nutrient and carbon inputs associated with dung from livestock (cattle) versus large wildlife (hippopotamus). Our loading model shows that per capita dung input by cattle is lower than for hippos, but total dung inputs by cattle constitute a significant portion of loading from large herbivores owing to the large numbers of cattle on the landscape. Cattle dung transfers higher amounts of limiting nutrients, major ions and dissolved organic carbon to aquatic ecosystems relative to hippo dung, and gross primary production and microbial biomass were higher in cattle dung treatments than in hippo dung treatments. Our results demonstrate that different forms of animal dung may influence aquatic ecosystems in fundamentally different ways when introduced into aquatic ecosystems as a terrestrially derived resource subsidy.
Collapse
Affiliation(s)
- Frank O. Masese
- Department of Fisheries and Aquatic Sciences, University of Eldoret, P.O. Box 1125-30100, Eldoret, Kenya
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Mary J. Kiplagat
- Department of Fisheries and Aquatic Sciences, University of Eldoret, P.O. Box 1125-30100, Eldoret, Kenya
| | | | - Amanda L. Subalusky
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Christopher L. Dutton
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - David M. Post
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Gabriel A. Singer
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Department of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| |
Collapse
|
22
|
Drought alters the biogeochemistry of boreal stream networks. Nat Commun 2020; 11:1795. [PMID: 32286262 PMCID: PMC7156665 DOI: 10.1038/s41467-020-15496-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/25/2020] [Indexed: 11/12/2022] Open
Abstract
Drought is a global phenomenon, with widespread implications for freshwater ecosystems. While droughts receive much attention at lower latitudes, their effects on northern river networks remain unstudied. We combine a reach-scale manipulation experiment, observations during the extreme 2018 drought, and historical monitoring data to examine the impact of drought in northern boreal streams. Increased water residence time during drought promoted reductions in aerobic metabolism and increased concentrations of reduced solutes in both stream and hyporheic water. Likewise, data during the 2018 drought revealed widespread hypoxic conditions and shifts towards anaerobic metabolism, especially in headwaters. Finally, long-term data confirmed that past summer droughts have led to similar metabolic alterations. Our results highlight the potential for drought to promote biogeochemical shifts that trigger poor water quality conditions in boreal streams. Given projected increases in hydrological extremes at northern latitudes, the consequences of drought for the health of running waters warrant attention. High latitude droughts are increasing, but their effects on freshwater systems are poorly understood. Here the authors investigate Sweden’s most severe drought in the last century and show that these dry conditions induce hypoxia and elevated methane production from streams.
Collapse
|
23
|
Benbow ME, Receveur JP, Lamberti GA. Death and Decomposition in Aquatic Ecosystems. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00017] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
|
24
|
Shurin JB, Aranguren-Riaño N, Duque Negro D, Echeverri Lopez D, Jones NT, Laverde-R O, Neu A, Pedroza Ramos A. Ecosystem effects of the world's largest invasive animal. Ecology 2020; 101:e02991. [PMID: 31994172 DOI: 10.1002/ecy.2991] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/04/2019] [Indexed: 11/06/2022]
Abstract
The keystone roles of mega-fauna in many terrestrial ecosystems have been lost to defaunation. Large predators and herbivores often play keystone roles in their native ranges, and some have established invasive populations in new biogeographic regions. However, few empirical examples are available to guide expectations about how mega-fauna affect ecosystems in novel environmental and evolutionary contexts. We examined the impacts on aquatic ecosystems of an emerging population of hippopotamus (Hippopotamus amphibus) that has been growing in Colombia over the last 25 yr. Hippos in Africa fertilize lakes and rivers by grazing on land and excreting wastes in the water. Stable isotopes indicate that terrestrial sources contribute more carbon in Colombian lakes containing hippo populations, and daily dissolved oxygen cycles suggest that their presence stimulates ecosystem metabolism. Phytoplankton communities were more dominated by cyanobacteria in lakes with hippos, and bacteria, zooplankton, and benthic invertebrate communities were similar regardless of hippo presence. Our results suggest that hippos recapitulate their role as ecosystem engineers in Colombia, importing terrestrial organic matter and nutrients with detectable impacts on ecosystem metabolism and community structure in the early stages of invasion. Ongoing range expansion may pose a threat to water resources.
Collapse
Affiliation(s)
- Jonathan B Shurin
- Section of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, 92093-0116, USA
| | - Nelson Aranguren-Riaño
- Unidad de Ecología en Sistemas Acuáticos-UDESA, Universidad Pedagógica y Tecnológica de Colombia, Avenida Central del Norte 39-115, Tunja, Boyacá, Colombia
| | - Daniel Duque Negro
- Unidad de Ecología en Sistemas Acuáticos-UDESA, Universidad Pedagógica y Tecnológica de Colombia, Avenida Central del Norte 39-115, Tunja, Boyacá, Colombia
| | - David Echeverri Lopez
- Corporación Autónoma Regional de las Cuencas de los Ríos Negros y Nare-CORNARE, Calle 13, No. 9-29, Municipio de la Unión, Antioquia, Colombia
| | - Natalie T Jones
- Section of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, 92093-0116, USA.,School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, 4072, Australia
| | - Oscar Laverde-R
- Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Sede Bogotá, D.C., Colombia
| | - Alexander Neu
- Section of Ecology, Behavior and Evolution, University of California San Diego, La Jolla, California, 92093-0116, USA
| | - Adriana Pedroza Ramos
- Unidad de Ecología en Sistemas Acuáticos-UDESA, Universidad Pedagógica y Tecnológica de Colombia, Avenida Central del Norte 39-115, Tunja, Boyacá, Colombia
| |
Collapse
|
25
|
Potential ecological and socio-economic effects of a novel megaherbivore introduction: the hippopotamus in Colombia. ORYX 2019. [DOI: 10.1017/s0030605318001588] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AbstractIntroduced species can have strong ecological, social and economic effects on their non-native environment. Introductions of megafaunal species are rare and may contribute to rewilding efforts, but they may also have pronounced socio-ecological effects because of their scale of influence. A recent introduction of the hippopotamus Hippopotamus amphibius into Colombia is a novel introduction of a megaherbivore onto a new continent, and raises questions about the future dynamics of the socio-ecological system into which it has been introduced. Here we synthesize current knowledge about the Colombian hippopotamus population, review the literature on the species to predict potential ecological and socio-economic effects of this introduction, and make recommendations for future study. Hippopotamuses can have high population growth rates (7–11%) and, on the current trajectory, we predict there could be 400–800 individuals in Colombia by 2050. The hippopotamus is an ecosystem engineer that can have profound effects on terrestrial and aquatic environments and could therefore affect the native biodiversity of the Magdalena River basin. Hippopotamuses are also aggressive and may pose a threat to the many inhabitants of the region who rely upon the Magdalena River for their livelihoods, although the species could provide economic benefits through tourism. Further research is needed to quantify the current and future size and distribution of this hippopotamus population and to predict the likely ecological, social and economic effects. This knowledge must be balanced with consideration of social and cultural concerns to develop appropriate management strategies for this novel introduction.
Collapse
|
26
|
Abstract
The United Republic of Tanzania (Tanzania) is rich in freshwater resources and biodiversity. In this article, we highlight the importance of Tanzanian rivers and make a case for the conservation of the freshwater and terrestrial species that rely on these rivers. We provide an overview of current knowledge on Tanzanian rivers and discuss progress towards implementation of the National Water Policy (2002) and Water Management Act (2009), two legislative instruments that have motivated environmental flow assessments on at least six major rivers and offer legal backing for river conservation. We examine major challenges that pose significant threats to water security for river ecosystems and humans in Tanzania, among those: (1) human population growth, (2) agricultural expansion, (3) river flow alterations, (4) industrialization, (5) introduced species, and (6) climate change. We conclude by offering recommendations for future river conservation efforts in Tanzania.
Collapse
|
27
|
Novel porous β-cyclodextrin/pillar[5]arene copolymer for rapid removal of organic pollutants from water. Carbohydr Polym 2019; 216:149-156. [DOI: 10.1016/j.carbpol.2019.04.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/28/2022]
|
28
|
Burkepile DE, Thurber RV. The Long Arm of Species Loss: How Will Defaunation Disrupt Ecosystems Down to the Microbial Scale? Bioscience 2019. [DOI: 10.1093/biosci/biz047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Deron E Burkepile
- Department of Ecology, Evolution and Marine Biology, and with the Marine Science Institute, both at the University of California, in Santa Barbara
| | | |
Collapse
|
29
|
McInturf AG, Pollack L, Yang LH, Spiegel O. Vectors with autonomy: what distinguishes animal‐mediated nutrient transport from abiotic vectors? Biol Rev Camb Philos Soc 2019; 94:1761-1773. [DOI: 10.1111/brv.12525] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Alexandra G. McInturf
- Department of Wildlife, Fish, and Conservation Biology University of California One Shields Avenue, Davis, CA 95616 U.S.A
| | - Lea Pollack
- Department of Environmental Science and Policy University of California One Shields Avenue, Davis, CA 95616 U.S.A
| | - Louie H. Yang
- Department of Entomology and Nematology University of California, Davis One Shields Avenue, Davis, CA, 95616 U.S.A
| | - Orr Spiegel
- School of Zoology, Faculty of Life Sciences Sherman Building, Tel Aviv University Tel Aviv, 69978 Israel
| |
Collapse
|
30
|
Wenger SJ, Subalusky AL, Freeman MC. The missing dead: The lost role of animal remains in nutrient cycling in North American Rivers. FOOD WEBS 2019. [DOI: 10.1016/j.fooweb.2018.e00106] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
31
|
Subalusky AL, Dutton CL, Njoroge L, Rosi EJ, Post DM. Organic matter and nutrient inputs from large wildlife influence ecosystem function in the Mara River, Africa. Ecology 2018; 99:2558-2574. [PMID: 30179253 DOI: 10.1002/ecy.2509] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/19/2018] [Accepted: 07/27/2018] [Indexed: 11/11/2022]
Abstract
Animals can be important vectors for the movement of resources across ecosystem boundaries. Animals add resources to ecosystems primarily through egestion, excretion, and carcasses, and the stoichiometry and bioavailability of these inputs likely interact with characteristics of the recipient ecosystem to determine their effects on ecosystem function. We studied the influence of hippopotamus excretion/egestion and wildebeest carcasses, and their interactions with discharge, in the Mara River, Kenya. We measured nutrient dissolution and decomposition rates of wildlife inputs, the influence of inputs on nutrient concentrations and nutrient limitation in the river and the influence of inputs on biofilm growth and function in both experimental streams and along a gradient of inputs in the river. We found that hippopotamus excretion/egestion increases ammonium and coarse particulate organic matter in the river, and wildebeest carcasses increase ammonium, soluble reactive phosphorus, and total phosphorus. Concentrations of dissolved carbon and nutrients in the water column increased along a gradient of wildlife inputs and during low discharge, although concentrations of particulate carbon decreased during low discharge due to deposition on the river bottom. Autotrophs were nitrogen limited and heterotrophs were carbon limited and nitrogen and phosphorus colimited upstream of animal inputs but there was no nutrient limitation downstream of inputs. In experimental streams, hippo and wildebeest inputs together increased biofilm gross primary production (GPP) and respiration (R). These results differed in the river, where low concentrations of hippo inputs increased gross primary production (GPP) and respiration (R) of biofilms, but high concentrations of hippo inputs in conjunction with wildebeest inputs decreased GPP. Our research shows that inputs from large wildlife alleviate nutrient limitation and stimulate ecosystem metabolism in the Mara River and that the extent to which these inputs subsidize the ecosystem is mediated by the quantity and quality of inputs and discharge of the river ecosystem. Thus, animal inputs provide an important ecological subsidy to this river, and animal inputs were likely important in many other rivers prior to the widespread extirpation of large wildlife.
Collapse
Affiliation(s)
- Amanda L Subalusky
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06511, USA.,Cary Institute of Ecosystem Studies, Millbrook, New York, 12545, USA
| | - Christopher L Dutton
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06511, USA
| | - Laban Njoroge
- Invertebrate Zoology Section, National Museums of Kenya, Nairobi, Kenya
| | - Emma J Rosi
- Cary Institute of Ecosystem Studies, Millbrook, New York, 12545, USA
| | - David M Post
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06511, USA
| |
Collapse
|
32
|
Subalusky AL, Post DM. Context dependency of animal resource subsidies. Biol Rev Camb Philos Soc 2018; 94:517-538. [DOI: 10.1111/brv.12465] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 08/24/2018] [Accepted: 08/30/2018] [Indexed: 12/01/2022]
Affiliation(s)
- Amanda L. Subalusky
- Department of Ecology and Evolutionary Biology Yale University New Haven CT 06511 U.S.A
- Cary Institute of Ecosystem Studies Millbrook NY 12545 U.S.A
| | - David M. Post
- Department of Ecology and Evolutionary Biology Yale University New Haven CT 06511 U.S.A
| |
Collapse
|
33
|
Stears K, McCauley DJ. Hippopotamus dung inputs accelerate fish predation by terrestrial consumers. Afr J Ecol 2018. [DOI: 10.1111/aje.12543] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Keenan Stears
- Department of Ecology, Evolution and Marine Biology Marine Science Institute University of California Santa Barbara California
| | - Douglas J. McCauley
- Department of Ecology, Evolution and Marine Biology Marine Science Institute University of California Santa Barbara California
| |
Collapse
|