1
|
Schmitt MH, Stears K, Donovan MK, Burkepile DE, Thompson DI. Integrating herbivore assemblages and woody plant cover in an African savanna to reveal how herbivores respond to ecosystem management. PLoS One 2022; 17:e0273917. [PMID: 36044453 PMCID: PMC9432757 DOI: 10.1371/journal.pone.0273917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/17/2022] [Indexed: 11/19/2022] Open
Abstract
African savannas are experiencing anthropogenically-induced stressors that are accelerating the increase of woody vegetation cover. To combat this, land managers frequently implement large-scale clearing of trees, which can have a cascading influence on mammalian herbivores. Studies rarely focus on how differences in woody cover influence the herbivore assemblage, making it difficult to assess how aggressive measures, or the lack of management, to counteract increasing woody cover affect the local composition and biodiversity of herbivores. We address this knowledge gap by applying a model-based clustering approach to field observations from MalaMala Game Reserve, South Africa to identify multiple herbivore-vegetation 'configurations,' defined as unique sets of herbivore assemblages (i.e., groups of herbivores) associated with differing woody plant covers. Our approach delineated how tree-clearing influences the distribution and abundance of the herbivore community in relation to surrounding savanna areas, which represent a natural mosaic of varying woody cover. Regardless of season, both intensively managed areas cleared of trees and unmanaged areas with high tree cover contained configurations that had depauperate assemblages of herbivores (low species richness, low abundance). By contrast, habitats with intermediate cover of woody vegetation had much higher richness and abundance. These results have substantial implications for managing African savannas in a rapidly changing climate.
Collapse
Affiliation(s)
- Melissa H. Schmitt
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- South African Environmental Observation Network, Ndlovu Node, Scientific Services, Kruger National Park, Phalaborwa, South Africa
| | - Keenan Stears
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- South African Environmental Observation Network, Ndlovu Node, Scientific Services, Kruger National Park, Phalaborwa, South Africa
| | - Mary K. Donovan
- School of Geographical Sciences and Urban Planning and Center for Global Discovery and Conservation Science, Arizona State University, Tempe, Arizona, United States of America
| | - Deron E. Burkepile
- Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- South African Environmental Observation Network, Ndlovu Node, Scientific Services, Kruger National Park, Phalaborwa, South Africa
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Dave I. Thompson
- South African Environmental Observation Network, Ndlovu Node, Scientific Services, Kruger National Park, Phalaborwa, South Africa
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa
| |
Collapse
|
2
|
Landscape Function Analysis: Responses to Bush Encroachment in a Semi-Arid Savanna in the Molopo Region, South Africa. SUSTAINABILITY 2022. [DOI: 10.3390/su14148616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Various factors lead to increased woody species density, biomass and cover (so-called ‘bush encroachment’) that influence ecosystem functioning and services in semi-arid rangelands. Ultimately, bush encroachment has adverse effects on human livelihoods. An increased understanding of ecosystem functioning in bush-encroached rangelands could contribute to improved management, conservation and restoration. This study, therefore, aimed to determine landscape functioning of bush-encroached and controlled savanna rangelands in the Molopo region, South Africa, by using the landscape function analysis (LFA) monitoring procedure. Mixed models revealed no significant differences based on LFA indices between bush-thickened and bush-controlled sites due to drought conditions that prevailed while the survey was carried out. Stability, which revealed the largest LFA contributing factors, always had the highest numerical value for sites that were still bush-encroached. Soil analyses revealed that grass litter patches from aeroplane-controlled sites had the highest average nutrient levels. As expected, high percentages of carbon and calcium levels were found in bush-encroached shrub litter patches. Bush-encroached landscapes are fully functional areas, especially under drought conditions. Long-term research is required to determine the effects successful management has on ecosystem functioning, especially during periods of higher rainfall.
Collapse
|
3
|
Sühs RB, Giehl ELH, Peroni N. Preventing traditional management can cause grassland loss within 30 years in southern Brazil. Sci Rep 2020; 10:783. [PMID: 31964935 PMCID: PMC6972928 DOI: 10.1038/s41598-020-57564-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 12/31/2019] [Indexed: 11/12/2022] Open
Abstract
Woody encroachment threatens several ecosystems around the world. In general, management of grasslands includes regulation of fire and grazing regimes. Changes in these two types of disturbances are potential drivers of woody encroachment. Here we assessed how the traditional management carried out by local landholders affects a highland grassland ecosystem in southern Brazil. We hypothesized that grasslands converted to protected areas undergo fast woody encroachment. To reconstruct changes in vegetation, we interviewed former and current landholders and coupled their knowledge with an analysis of aerial and satellite images. During the first 11 years without fire and cattle, woody encroachment in grasslands increased exponentially. Woody encroachment occurred mostly by the replacement of grasslands by shrublands. Meanwhile, grasslands under traditional management remained almost unchanged for the last 40 years. The management of fire by local landholders has been part of their traditional practices for decades. Such management prevents large-scale wildfires and maintains natural highland grasslands. The quick pace of shrub encroachment in such grasslands threatens its exclusive diversity, human well-being and regional cultural heritage. Thus, conservation policies are needed to regulate and instruct about the use of fire as a management tool in highland grasslands of southern Brazil.
Collapse
Affiliation(s)
- Rafael Barbizan Sühs
- Department of Ecology and Zoology, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil.
| | - Eduardo Luís Hettwer Giehl
- Department of Ecology and Zoology, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil
| | - Nivaldo Peroni
- Department of Ecology and Zoology, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil
| |
Collapse
|
5
|
Teka H, Madakadze I, Hassen A, Angassa A, Mussa M. Impacts of a mineral lick-centred land use system on woody vegetation cover in an East African Savannah. Afr J Ecol 2018. [DOI: 10.1111/aje.12503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Habtamu Teka
- Department of Animal and Range Science; University of Madda Walabu; Bale-Robe Ethiopia
| | - I.C. Madakadze
- Department of Plant Production and Soil Science; University of Pretoria; Pretoria South Africa
| | - Abubeker Hassen
- Department of Animal and Wildlife Science; University of Pretoria; Pretoria South Africa
| | - Ayana Angassa
- Department of Animal Science and Production; Botswana University of Agriculture and Natural Resources; Gaborone Botswana
| | - Mohammed Mussa
- Department of Animal and Range Science; University of Madda Walabu; Bale-Robe Ethiopia
| |
Collapse
|
6
|
Schwarz K, Finckh M, Stolter C. Influence of differently managed bush-encroached sites on the large herbivore distribution in the Namibian Savannah. Afr J Ecol 2017. [DOI: 10.1111/aje.12451] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kathrin Schwarz
- Department of Biodiversity; Evolution and Ecology of Plants; Biocentre Klein Flottbek and Botanical Garden; University of Hamburg; Hamburg Germany
| | - Manfred Finckh
- Department of Biodiversity; Evolution and Ecology of Plants; Biocentre Klein Flottbek and Botanical Garden; University of Hamburg; Hamburg Germany
| | - Caroline Stolter
- Department of Animal Ecology and Nature Conservation; Biocenter Grindel, University of Hamburg; Hamburg Germany
| |
Collapse
|
7
|
Tiki W, Oba G, Tvedt T. Human stewardship or ruining cultural landscapes of the ancient Tula wells, southern Ethiopia. THE GEOGRAPHICAL JOURNAL 2011; 177:62-78. [PMID: 21560273 DOI: 10.1111/j.1475-4959.2010.00369.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This article uses the concepts of "human stewardship" and "ruined landscape" as a theoretical framework for analysing the community's perception of landscape change in the ancient tula well system of Borana in southern Ethiopia. The ancient tula well system, the main permanent water source, has been in operation for more than five centuries and it closely links human activity and the environment. The welfare of the tula well system and the performance of the Borana pastoral system are directly related. Borana management of the tula wells uses concepts such as laaf aadaa seeraa and laaf bade to differentiate between ‘land managed by customary laws’ (hereafter human stewardship) and ‘lost’ or ‘ruined’ land (laaf bade). The cultural landscapes of the ancient wells have undergone changes from ecosystems featuring ‘human stewardship’ (before the 1960s), that is, laaf aadaa seeraa to ‘ruined landscapes’ (after the 1960s), that is, laaf bade. Our interest is in understanding how the Borana perceive the impact of land use changes from these two conceptual perspectives. In group discussions, key informant interviews and household surveys across five of the nine well clusters, we found that the society described the changed tula cultural landscape in terms of drivers of well dynamics (i.e. use and disuse), break up of land use zonations, patterns of human settlement (traditional versus peri-urban), expansion of crop cultivation, and changes in environmental quality. Using the two concepts, we analysed linkages between changing patterns of land use that transformed the system from laaf aadaa seeraa, which ensured human stewardship, to laaf bade, which resulted in ruined landscapes. From these we analysed environmental narratives that showed how the society differentiated the past human stewardship that ensured sustainable landscape management from the present ruining of tula well cultural landscapes.
Collapse
|