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Faulstich L, Wollenweber S, Reinhardt-Imjela C, Arendt R, Schulte A, Hollert H, Schiwy S. Ecotoxicological evaluation of surface waters in Northern Namibia. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:456. [PMID: 38630192 PMCID: PMC11024038 DOI: 10.1007/s10661-024-12613-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024]
Abstract
The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them.
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Affiliation(s)
- L Faulstich
- Freie Universität Berlin, Berlin, Germany.
- Goethe-Universität Frankfurt, Frankfurt, Germany.
| | | | | | - R Arendt
- Freie Universität Berlin, Berlin, Germany
| | - A Schulte
- Freie Universität Berlin, Berlin, Germany
| | - H Hollert
- Goethe-Universität Frankfurt, Frankfurt, Germany
| | - S Schiwy
- Goethe-Universität Frankfurt, Frankfurt, Germany
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Huang RM, Maré C, Guldemond RAR, Pimm SL, van Aarde RJ. Protecting and connecting landscapes stabilizes populations of the Endangered savannah elephant. SCIENCE ADVANCES 2024; 10:eadk2896. [PMID: 38181078 PMCID: PMC10776014 DOI: 10.1126/sciadv.adk2896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/01/2023] [Indexed: 01/07/2024]
Abstract
The influence of protected areas on the growth of African savannah elephant populations is inadequately known. Across southern Africa, elephant numbers grew at 0.16% annually for the past quarter century. Locally, much depends on metapopulation dynamics-the size and connections of individual populations. Population numbers in large, connected, and strictly protected areas typically increased, were less variable from year to year, and suffered less from poaching. Conversely, populations in buffer areas that are less protected but still connected have more variation in growth from year to year. Buffer areas also differed more in their growth rates, likely due to more threats and dispersal opportunities in the face of such dangers. Isolated populations showed consistently high growth due to a lack of emigration. This suggests that "fortress" conservation generally maintains high growth, while anthropogenic-driven source-sink dynamics within connected conservation clusters drive stability in core areas and variability in buffers.
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Affiliation(s)
- Ryan M. Huang
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Celesté Maré
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Robert A. R. Guldemond
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Stuart L. Pimm
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Rudi J. van Aarde
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
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Brown MB, Fennessy JT, Crego RD, Fleming CH, Alves J, Brandlová K, Fennessy S, Ferguson S, Hauptfleisch M, Hejcmanova P, Hoffman R, Leimgruber P, Masiaine S, McQualter K, Mueller T, Muller B, Muneza A, O'Connor D, Olivier AJ, Rabeil T, Seager S, Stacy-Dawes J, van Schalkwyk L, Stabach J. Ranging behaviours across ecological and anthropogenic disturbance gradients: a pan-African perspective of giraffe ( Giraffa spp .) space use. Proc Biol Sci 2023; 290:20230912. [PMID: 37357852 PMCID: PMC10291724 DOI: 10.1098/rspb.2023.0912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/26/2023] [Indexed: 06/27/2023] Open
Abstract
Animal movement behaviours are shaped by diverse factors, including resource availability and human impacts on the landscape. We generated home range estimates and daily movement rate estimates for 149 giraffe (Giraffa spp.) from all four species across Africa to evaluate the effects of environmental productivity and anthropogenic disturbance on space use. Using the continuous time movement modelling framework and a novel application of mixed effects meta-regression, we summarized overall giraffe space use and tested for the effects of resource availability and human impact on 95% autocorrelated kernel density estimate (AKDE) size and daily movement. The mean 95% AKDE was 359.9 km2 and the mean daily movement was 14.2 km, both with marginally significant differences across species. We found significant negative effects of resource availability, and significant positive effects of resource heterogeneity and protected area overlap on 95% AKDE size. There were significant negative effects of overall anthropogenic disturbance and positive effects of the heterogeneity of anthropogenic disturbance on daily movements and 95% AKDE size. Our results provide unique insights into the interactive effects of resource availability and anthropogenic development on the movements of a large-bodied browser and highlight the potential impacts of rapidly changing landscapes on animal space-use patterns.
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Affiliation(s)
- Michael Butler Brown
- Giraffe Conservation Foundation, PO Box 86099, Eros, Windhoek, Namibia
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
| | | | - Ramiro D. Crego
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Christen H. Fleming
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Joel Alves
- Wildscapes Veterinary & Conservation Services, Hoedspruit, South Africa
| | - Karolina Brandlová
- Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamycka 129, 16500 Prague, Czechia
| | | | - Sara Ferguson
- Giraffe Conservation Foundation, PO Box 86099, Eros, Windhoek, Namibia
| | - Morgan Hauptfleisch
- Biodiversity Research Centre, Namibia University of Science and Technology, 8 Johann Albrecht Street, Windhoek, Namibia
| | - Pavla Hejcmanova
- Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamycka 129, 16500 Prague, Czechia
| | - Rigardt Hoffman
- Giraffe Conservation Foundation, PO Box 86099, Eros, Windhoek, Namibia
| | - Peter Leimgruber
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Symon Masiaine
- Conservation Science & Wildlife Health, San Diego Zoo Wildlife Alliance, San Diego, CA, USA
| | - Kylie McQualter
- Centre for Ecosystem Studies, School of Biological Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, 2052, Australia
| | - Thomas Mueller
- Senckenberg Biodiversity and Climate Research Centre and Department of Biological Science, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Ben Muller
- Wildscapes Veterinary & Conservation Services, Hoedspruit, South Africa
| | - Arthur Muneza
- Giraffe Conservation Foundation, PO Box 86099, Eros, Windhoek, Namibia
| | - David O'Connor
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
- Senckenberg Biodiversity and Climate Research Centre and Department of Biological Science, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Adriaan Jacobus Olivier
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | | | | | - Jenna Stacy-Dawes
- Conservation Science & Wildlife Health, San Diego Zoo Wildlife Alliance, San Diego, CA, USA
| | - Louis van Schalkwyk
- Office of the State Veterinarian, Department of Agriculture, Land Reform and Rural Development, Kruger National Park, Skukuza, South Africa
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Jared Stabach
- Smithsonian National Zoo and Conservation Biology Institute, Conservation Ecology Center, 1500 Remount Rd, Front Royal, VA 22630, USA
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