1
|
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.
Collapse
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
| |
Collapse
|
2
|
Foggin CM, Rosen LE, Henton MM, Buys A, Floyd T, Turner AD, Tarbin J, Lloyd AS, Chaitezvi C, Ellis RJ, Roberts HC, Dastjerdi A, Nunez A, van Vliet AHM, Steinbach F. Pasteurella sp. associated with fatal septicaemia in six African elephants. Nat Commun 2023; 14:6398. [PMID: 37880229 PMCID: PMC10600241 DOI: 10.1038/s41467-023-41987-z] [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: 02/03/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023] Open
Abstract
The sudden mortality of African elephants (Loxodonta africana) in Botswana and Zimbabwe in 2020 provoked considerable public interest and speculation. Poaching and malicious poisoning were excluded early on in the investigation. Other potential causes included environmental intoxication, infectious diseases, and increased habitat stress due to ongoing drought. Here we show evidence of the mortalities in Zimbabwe as fatal septicaemia associated with Bisgaard taxon 45, an unnamed close relative of Pasteurella multocida. We analyse elephant carcasses and environmental samples, and fail to find evidence of cyanobacterial or other intoxication. Post-mortem and histological findings suggest a bacterial septicaemia similar to haemorrhagic septicaemia caused by P. multocida. Biochemical tests and 16S rDNA analysis of six samples and genomic analysis of one sample confirm the presence of Bisgaard taxon 45. The genome sequence contains many of the canonical P. multocida virulence factors associated with a range of human and animal diseases, including the pmHAS gene for hyaluronidase associated with bovine haemorrhagic septicaemia. Our results demonstrate that Bisgaard taxon 45 is associated with a generalised, lethal infection and that African elephants are susceptible to opportunistically pathogenic Pasteurella species. This represents an important conservation concern for elephants in the largest remaining metapopulation of this endangered species.
Collapse
Affiliation(s)
| | - Laura E Rosen
- Transboundary Epidemiology Analytics, LLC, Alpharetta, GA, USA.
- Victoria Falls Wildlife Trust, Victoria Falls, Zimbabwe.
| | | | - Angela Buys
- Design Biologix, Erasmusrand, Pretoria, South Africa
| | - Toby Floyd
- Pathology and Animal Sciences Department, Animal and Plant Health Agency Weybridge, Addlestone, Surrey, KT15 3NB, UK
| | - Andrew D Turner
- Centre for Environment Fisheries and Aquaculture Science, The Nothe, Weymouth, Dorset, DT4 8UB, UK
| | | | | | | | - Richard J Ellis
- Surveillance and Laboratory Services Department, Animal and Plant Health Agency Weybridge, Addlestone, Surrey, KT15 3NB, UK
| | - Helen C Roberts
- Department for Environment Food & Rural Affairs, Nobel House, 17 Smith Square, London, SW1P 3JR, UK
| | - Akbar Dastjerdi
- Virology Department, Animal and Plant Health Agency Weybridge, Addlestone, Surrey, KT15 3NB, UK
| | - Alejandro Nunez
- Pathology and Animal Sciences Department, Animal and Plant Health Agency Weybridge, Addlestone, Surrey, KT15 3NB, UK
| | - Arnoud H M van Vliet
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, UK
| | - Falko Steinbach
- Virology Department, Animal and Plant Health Agency Weybridge, Addlestone, Surrey, KT15 3NB, UK
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, UK
| |
Collapse
|
3
|
Ndlovu M, Madiri T, Madhlamoto D, Tadyanehondo K, Vambe A, Mungoni E. Age-sex structure of drought-driven African elephant (Loxodonta africana) mortality in Hwange National Park, Zimbabwe. SCIENTIFIC AFRICAN 2022. [DOI: 10.1016/j.sciaf.2022.e01459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
4
|
MacDonald AM, Jones PF, Hanlon JA, Martin BH, Jakes AF. How did the deer cross the fence: An evaluation of wildlife-friendlier fence modifications to facilitate deer movement. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.991765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Fences are a common feature throughout the landscape of North America’s Great Plains region. Knowledge surrounding the harmful implication that fences have on the movement of wildlife, specifically ungulates, is expanding. Across the region, it is accepted that there is a need to mitigate the impacts of barbed wire fencing and that “wildlife-friendlier” fence designs are emerging as a practical tool to meet these goals. Here we evaluate the response of sympatric deer species to the implementation of two fence modifications, fastening the top two wires together using clips and the installation of polyvinyl chloride (PVC) pipe to encompass the top two wires. We also aim to determine the optimal top wire height to allow for successful crossing by deer, with the goal to provide a more robust understanding of effective wildlife-friendlier fence standards. We used remote trail cameras to capture crossing events and recorded responses for mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus). Using generalized linear mixed modelling, we tested the influence modifications had on crossing success and decisions prior to and after the modifications were installed compared to control sites. We found that these modifications had little impact on deer crossing behavior. We determined that wire height had the greatest impact on the permeability of fences, but that deer permeability was strongly influenced by species and sex. We found that the current maximum recommended top wire height of 102 cm (40 inches) is adequate to allow individuals of both deer species to cross over the fence, with the exception of female mule deer. Our results also indicate as the top wire height reaches 110 cm (43 inches) or higher, that the probability of successfully jumping over the fence dramatically drops off, with the exception for male mule deer. We recommend the installation of clips as a cost-effective method to lower top wire height and PVC pipe to improve fence visibility and potentially reduce entanglement events, all while effectively keeping livestock in intended pastures.
Collapse
|
5
|
Huang RM, van Aarde RJ, Pimm SL, Chase MJ, Leggett K. Mapping potential connections between Southern Africa's elephant populations. PLoS One 2022; 17:e0275791. [PMID: 36219597 PMCID: PMC9553058 DOI: 10.1371/journal.pone.0275791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022] Open
Abstract
Southern Africa spans nearly 7 million km2 and contains approximately 80% of the world’s savannah elephants (Loxodonta africana) mostly living in isolated protected areas. Here we ask what are the prospects for improving the connections between these populations? We combine 1.2 million telemetry observations from 254 elephants with spatial data on environmental factors and human land use across eight southern African countries. Telemetry data show what natural features limit elephant movement and what human factors, including fencing, further prevent or restrict dispersal. The resulting intersection of geospatial data and elephant presences provides a map of suitable landscapes that are environmentally appropriate for elephants and where humans allow elephants to occupy. We explore the environmental and anthropogenic constraints in detail using five case studies. Lastly, we review all the major potential connections that may remain to connect a fragmented elephant metapopulation and document connections that are no longer feasible.
Collapse
Affiliation(s)
- Ryan M. Huang
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
- * E-mail: (RMH); (RJA)
| | - Rudi J. van Aarde
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- * E-mail: (RMH); (RJA)
| | - Stuart L. Pimm
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | | | - Keith Leggett
- Fowlers Gap Arid Zone Research Station, UNSW Sydney, Sydney, Fowlers Gap, Australia
| |
Collapse
|
6
|
Srivastava A, Shukla P. Cyanobacterial Peptides: Metabolic Potential and Environmental Fate. Protein Pept Lett 2022; 29:375-378. [DOI: 10.2174/0929866529666220314111105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/15/2022] [Accepted: 01/21/2022] [Indexed: 11/22/2022]
Affiliation(s)
- Amit Srivastava
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States of America
| | - Pratyoosh Shukla
- Enzyme
Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu
University, Varanasi 221005, Uttar Pradesh, India
| |
Collapse
|
7
|
Wiśniewska M, Puga-Gonzalez I, Lee P, Moss C, Russell G, Garnier S, Sueur C. Simulated poaching affects global connectivity and efficiency in social networks of African savanna elephants—An exemplar of how human disturbance impacts group-living species. PLoS Comput Biol 2022; 18:e1009792. [PMID: 35041648 PMCID: PMC8797174 DOI: 10.1371/journal.pcbi.1009792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 01/28/2022] [Accepted: 12/23/2021] [Indexed: 11/19/2022] Open
Abstract
Selective harvest, such as poaching, impacts group-living animals directly through mortality of individuals with desirable traits, and indirectly by altering the structure of their social networks. Understanding the relationship between disturbance-induced, structural network changes and group performance in wild animals remains an outstanding problem. To address this problem, we evaluated the immediate effect of disturbance on group sociality in African savanna elephants—an example, group-living species threatened by poaching. Drawing on static association data from ten free-ranging groups, we constructed one empirically based, population-wide network and 100 virtual networks; performed a series of experiments ‘poaching’ the oldest, socially central or random individuals; and quantified the immediate change in the theoretical indices of network connectivity and efficiency of social diffusion. Although the social networks never broke down, targeted elimination of the socially central conspecifics, regardless of age, decreased network connectivity and efficiency. These findings hint at the need to further study resilience by modeling network reorganization and interaction-mediated socioecological learning, empirical data permitting. The main contribution of our work is in quantifying connectivity together with global efficiency in multiple social networks that feature the sociodemographic diversity likely found in wild elephant populations. The basic design of our simulation makes it adaptable for hypothesis testing about the consequences of anthropogenic disturbance or lethal management on social interactions in a variety of group-living species with limited, real-world data.
Collapse
Affiliation(s)
- Maggie Wiśniewska
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
- * E-mail:
| | - Ivan Puga-Gonzalez
- Institutt for global utvikling og samfunnsplanlegging, Universitetet i Agder, Kristiansand, Norway
- Center for Modeling Social Systems at NORCE, Kristiansand, Norway
| | - Phyllis Lee
- Amboseli Trust for Elephants, Nairobi, Kenya
- Faculty of Natural Science, University of Stirling, Stirling, United Kingdom
| | | | - Gareth Russell
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Simon Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, United States of America
| | - Cédric Sueur
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
- Institut Universitaire de France, Paris, France
| |
Collapse
|
8
|
Veerman J, Kumar A, Mishra DR. Exceptional landscape-wide cyanobacteria bloom in Okavango Delta, Botswana in 2020 coincided with a mass elephant die-off event. HARMFUL ALGAE 2022; 111:102145. [PMID: 35016759 DOI: 10.1016/j.hal.2021.102145] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/19/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
In 2020, nearly 400 elephants died within the Okavango Delta region in Botswana, creating the worst-ever elephant mass die-off event in history. This catastrophic event was widely blamed on toxic cyanobacterial blooms after lab results showed the presence of toxin-forming cyanobacteria in inland waters of the Delta. However, it did not explain why we saw this mass die-off of elephants in 2020 and not in previous years. We conducted a landscape-wide time-series analysis using freely available European Space Agency's Sentinel-2 and NASA's Landsat-8 satellite data. We used existing bio-optical models, Normalized Difference Chlorophyll Index and Green Line Height, as proxies for chlorophyll-a and phycocyanin (cyanobacteria) concentrations. We found that 2020 was an exceptional year for cyanobacteria blooms in the Okavango Delta region compared to the past three years (2017-2019). Bloom phenology indicated that the cyanobacteria blooms initiated in September-October 2019, experienced an exponential growth reaching peak in January-February 2020, and eventually senescing in June 2020. This being a notoriously data-scarce region of the world, we did not have any means to perform site-specific validation of the models. Although magnitude and timeline of the blooms coincided with the timeline of elephant death reports, our study do not confirm it to be the trigger. For the first time, we show the widespread nature of these blooms across the landscape, which may have increased the toxin exposure for elephants. We theorize that 2020 might have been the first year for such a mass die-off event, but it will certainly not be the last because warming trends under changing climate are creating increasingly suitable conditions for these blooms to be pervasive and ubiquitous. Through this preliminary study, we demonstrate the critical need for frequent and comprehensive monitoring of toxic cyanobacterial blooms in the Delta to avoid another such event in the future.
Collapse
Affiliation(s)
- Jan Veerman
- Department of Geography, University of Georgia, 210 Field Street, Room 204, Athens, GA 30602 USA
| | - Abhishek Kumar
- Department of Geography, University of Georgia, 210 Field Street, Room 204, Athens, GA 30602 USA; Department of Environmental Conservation, University of Massachusetts, Amherst, MA 01003, USA
| | - Deepak R Mishra
- Department of Geography, University of Georgia, 210 Field Street, Room 204, Athens, GA 30602 USA.
| |
Collapse
|
9
|
Maniyar CB, Kumar A, Mishra DR. Continuous and Synoptic Assessment of Indian Inland Waters for Harmful Algae Blooms. HARMFUL ALGAE 2022; 111:102160. [PMID: 35016766 DOI: 10.1016/j.hal.2021.102160] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/02/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Cyanobacterial Harmful Algal Blooms (CyanoHABs) are progressively becoming a major water quality, socioeconomic, and health hazard worldwide. In India, there are frequent episodes of severe CyanoHABs, which are left untreated due to a lack of awareness and monitoring infrastructure, affecting the economy of the country gravely. In this study, for the first time, we present a country-wide analysis of CyanoHABs in India by developing a novel interactive cloud-based dashboard called "CyanoKhoj" in Google Earth Engine (GEE) which uses Sentinel-3 Ocean and Land Colour Instrument (OLCI) remotely sensed datasets. The main goal of this study was to showcase the utility of CyanoKhoj for rapid monitoring and discuss the widespread CyanoHABs problems across India. We demonstrate the utility of Cyanokhoj by including select case studies of lakes and reservoirs geographically spread across five states: Bargi and Gandhisagar Dams in Madhya Pradesh, Hirakud Reservoir in Odisha, Ukai Dam in Gujarat, Linganamakki Reservoir in Karnataka, and Pulicat Lake in Tamil Nadu. These sites were studied from September to November 2018 using CyanoKhoj, which is capable of near-real-time monitoring and country-wide assessment of CyanoHABs. We used CyanoKhoj to prepare spatiotemporal maps of Chlorophyll-a (Chl-a) content and Cyanobacterial Cell Density (CCD) to study the local spread of the CyanoHABs and their phenology in these waterbodies. A first-ever all-India CCD map is also presented for the year 2018, which highlights the spatial spread of CyanoHABs throughout the country (32 large waterbodies across India with severe bloom: CCD>2,500,000). Results indicate that CyanoHABs are most prevalent in nutrient-rich waterbodies prone to industrial and other nutrient-rich discharges. A clear temporal evolution of the blooms showed that they are dominant during the post-monsoon season (September-October) when the nutrient concentrations in the waterbodies are at their peak, and they begin to decline towards winter (November-December). CyanoKhoj is an open-source tool that can have a significant broader impact in mapping CyanoHABs not only throughout cyanobacteria data-scarce India, but on a global level using archived and future Sentinel-3A/B OLCI data.
Collapse
Affiliation(s)
- Chintan B Maniyar
- Photogrammetry and Remote Sensing Department, Indian Institute of Remote Sensing (IIRS), ISRO, India; Department of Geography, University of Georgia, GA, USA
| | - Abhishek Kumar
- Department of Geography, University of Georgia, GA, USA; Department of Environmental Conservation, University of Massachusetts Amherst, MA, USA.
| | | |
Collapse
|
10
|
Abstract
The U.N. has declared 2021-2030 the 'decade of restoration' (https://www.decadeonrestoration.org). This initiative aspires to many actions, but its agenda must include 'reconnecting nature'. Even when natural habitats remain, they often come in fragments too small or isolated to sustain viable populations. Human activities surround habitats with unsuitable areas or constrict animals' movements with artificial barriers, such as roads or fences. The harm this fragmentation causes is evident. Here, we discuss various actions to mitigate its problems, seeking explicit evidence of their efficacy. These actions range from small-scale, controlled experiments to continent-wide programmes to allow species the freedom to roam. Even simple connections, such as highway overpasses or tunnels, usually allow movement such that the genetic and demographic problems that beset small, isolated populations may be diminished. Showing that species move when we give them the chance to do so may be a sufficient measure of success, even if we do not always understand the consequences in detail.
Collapse
Affiliation(s)
- Stuart L Pimm
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, USA; Saving Nature, Durham, NC 27713, USA.
| | | | | | - Ryan Huang
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, USA
| |
Collapse
|