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Reuber VM, Westbury MV, Rey-Iglesia A, Asefa A, Farwig N, Miehe G, Opgenoorth L, Šumbera R, Wraase L, Wube T, Lorenzen ED, Schabo DG. Topographic barriers drive the pronounced genetic subdivision of a range-limited fossorial rodent. Mol Ecol 2024; 33:e17271. [PMID: 38279205 DOI: 10.1111/mec.17271] [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: 04/13/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 01/28/2024]
Abstract
Due to their limited dispersal ability, fossorial species with predominantly belowground activity usually show increased levels of population subdivision across relatively small spatial scales. This may be exacerbated in harsh mountain ecosystems, where landscape geomorphology limits species' dispersal ability and leads to small effective population sizes, making species relatively vulnerable to environmental change. To better understand the environmental drivers of species' population subdivision in remote mountain ecosystems, particularly in understudied high-elevation systems in Africa, we studied the giant root-rat (Tachyoryctes macrocephalus), a fossorial rodent confined to the afro-alpine ecosystem of the Bale Mountains in Ethiopia. Using mitochondrial and low-coverage nuclear genomes, we investigated 77 giant root-rat individuals sampled from nine localities across its entire ~1000 km2 range. Our data revealed a distinct division into a northern and southern group, with no signs of gene flow, and higher nuclear genetic diversity in the south. Landscape genetic analyses of the mitochondrial and nuclear genomes indicated that population subdivision was driven by slope and elevation differences of up to 500 m across escarpments separating the north and south, potentially reinforced by glaciation of the south during the Late Pleistocene (~42,000-16,000 years ago). Despite this landscape-scale subdivision between the north and south, weak geographic structuring of sampling localities within regions indicated gene flow across distances of at least 16 km at the local scale, suggesting high, aboveground mobility for relatively long distances. Our study highlights that despite the potential for local-scale gene flow in fossorial species, topographic barriers can result in pronounced genetic subdivision. These factors can reduce genetic variability, which should be considered when developing conservation strategies.
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Affiliation(s)
- Victoria M Reuber
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
| | | | | | - Addisu Asefa
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
- Ethiopian Wildlife Conservation Authority, Addis Ababa, Ethiopia
| | - Nina Farwig
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
| | - Georg Miehe
- Department of Geography, Vegetation Geography, University of Marburg, Marburg, Germany
| | - Lars Opgenoorth
- Department of Biology, Plant Ecology & Geobotany, University of Marburg, Marburg, Germany
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Radim Šumbera
- Department of Zoology, University of South Bohemia, České Budějovice, Czech Republic
| | - Luise Wraase
- Department of Geography, Environmental Informatics, University of Marburg, Marburg, Germany
| | - Tilaye Wube
- Department of Zoological Sciences, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Dana G Schabo
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
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Asefa A, Reuber V, Miehe G, Wraase L, Wube T, Schabo DG, Farwig N. Human activities modulate reciprocal effects of a subterranean ecological engineer rodent, Tachyoryctes macrocephalus, on Afroalpine vegetation cover. Ecol Evol 2023; 13:e10337. [PMID: 37465614 PMCID: PMC10350814 DOI: 10.1002/ece3.10337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/21/2023] [Accepted: 07/04/2023] [Indexed: 07/20/2023] Open
Abstract
Human activities, directly and indirectly, impact ecological engineering activities of subterranean rodents. As engineering activities of burrowing rodents are affected by, and reciprocally affect vegetation cover via feeding, burrowing and mound building, human influence such as settlements and livestock grazing, could have cascading effects on biodiversity and ecosystem processes such as bioturbation. However, there is limited understanding of the relationship between human activities and burrowing rodents. The aim of this study was therefore to understand how human activities influence the ecological engineering activity of the giant root-rat (Tachyoryctes macrocephalus), a subterranean rodent species endemic to the Afroalpine ecosystem of the Bale Mountains of Ethiopia. We collected data on human impact, burrowing activity and vegetation during February and March of 2021. Using path analysis, we tested (1) direct effects of human settlement on the patterns of livestock grazing intensity, (2) direct and indirect impacts of humans and livestock grazing intensity on the root-rat burrow density and (3) whether human settlement and livestock grazing influence the effects of giant root-rat burrow density on vegetation and vice versa. We found lower levels of livestock grazing intensity further from human settlement than in its proximity. We also found a significantly increased giant root-rat burrow density with increasing livestock grazing intensity. Seasonal settlement and livestock grazing intensity had an indirect negative and positive effect on giant root-rat burrow density, respectively, both via vegetation cover. Analysing the reciprocal effects of giant root-rat on vegetation, we found a significantly decreased vegetation cover with increasing density of giant root-rat burrows, and indirectly with increasing livestock grazing intensity via giant root-rat burrow density. Our results demonstrate that giant root-rats play a synanthropic engineering role that affects vegetation structure and ecosystem processes.
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Affiliation(s)
- Addisu Asefa
- Department of Biology, Conservation EcologyPhilipps‐Universität MarburgMarburgGermany
| | - Victoria Reuber
- Department of Biology, Conservation EcologyPhilipps‐Universität MarburgMarburgGermany
| | - Georg Miehe
- Department of Geography, Vegetation GeographyPhilipps‐Universität MarburgMarburgGermany
| | - Luise Wraase
- Department of Geography, Environmental InformaticsPhilipps‐Universität MarburgMarburgGermany
| | - Tilaye Wube
- Department of Zoology, College of Natural and Computational SciencesAddis Ababa UniversityAddis AbabaEthiopia
| | - Dana G. Schabo
- Department of Biology, Conservation EcologyPhilipps‐Universität MarburgMarburgGermany
| | - Nina Farwig
- Department of Biology, Conservation EcologyPhilipps‐Universität MarburgMarburgGermany
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Valkó O, Kelemen A, Kiss O, Deák B. Patch and matrix characteristics determine the outcome of ecosystem engineering by mole rats in dry grasslands. PeerJ 2022; 10:e14582. [PMID: 36540798 PMCID: PMC9760028 DOI: 10.7717/peerj.14582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Background Burrowing mammals are important ecosystem engineers, especially in open ecosystems where they create patches that differ from the surrounding matrix in their structure or ecosystem functions. Methods We evaluated the fine-scale effects of a subterranean ecosystem engineer, the Lesser blind mole rat on the vegetation composition of sandy dry grasslands in Hungary. In this model system we tested whether the characteristics of the patch (mound size) and the matrix (total vegetation cover in the undisturbed grassland) influence the structural and functional contrasts between the mounds and the undisturbed grasslands. We sampled the vegetation of 80 mounds and 80 undisturbed grassland plots in four sites, where we recorded the total vegetation cover, and the occurrence and cover of each vascular plant species. We used two proxies to characterise the patches (mounds) and the matrix (undisturbed grassland): we measured the perimeter of the mounds and estimated the total vegetation cover of the undisturbed grasslands. First, we compared the vegetation characteristics of the mounds and the surrounding grasslands with general linear models. Second, we characterised the contrasts between the mounds and the undisturbed grassland by relative response indices (RRIs) of the vegetation characteristics studied in the first step. Results Species composition of the vegetation of the mounds and undisturbed grasslands was well separated in three out of the four study sites. Mounds were characterised by lower vegetation cover, lower cover of perennial graminoids, and higher diversity, and evenness compared to undisturbed grasslands. The contrast in vegetation cover between mounds and undisturbed grasslands increased with decreasing patch size. Increasing vegetation cover in the matrix grasslands increased the contrasts between the mounds and undisturbed grasslands in terms of total cover, perennial graminoid cover, diversity, and evenness. Our results suggest that mole rat mounds provide improved establishment conditions for subordinate species, because they are larger than other types of natural gaps and are characterised by less intense belowground competition. The ecosystem engineering effect, i.e., the contrast between the patches and the matrix was the largest in the more closed grasslands.
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Affiliation(s)
- Orsolya Valkó
- Lendület Seed Ecology Research Group, Institute of Ecology and Botany, Centre for Ecological Research, Vácrátót, Hungary
| | - András Kelemen
- Lendület Seed Ecology Research Group, Institute of Ecology and Botany, Centre for Ecological Research, Vácrátót, Hungary,Department of Ecology, University of Szeged, Szeged, Hungary
| | - Orsolya Kiss
- Institute of Animal Sciences and Wildlife Management, Faculty of Agriculture, University of Szeged, Hódmezővásárhely, Hungary
| | - Balázs Deák
- Lendület Seed Ecology Research Group, Institute of Ecology and Botany, Centre for Ecological Research, Vácrátót, Hungary
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The activity of a subterranean small mammal alters Afroalpine vegetation patterns and is positively affected by livestock grazing. Basic Appl Ecol 2022. [DOI: 10.1016/j.baae.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Reuber VM, Rey-Iglesia A, Westbury MV, Cabrera AA, Farwig N, Skovrind M, Šumbera R, Wube T, Opgenoorth L, Schabo DG, Lorenzen ED. Complete mitochondrial genome of the giant root-rat ( Tachyoryctes macrocephalus). Mitochondrial DNA B Resour 2021; 6:2191-2193. [PMID: 34263047 PMCID: PMC8253177 DOI: 10.1080/23802359.2021.1944388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The endangered giant root-rat (Tachyoryctes macrocephalus, also known as giant mole rat) is a fossorial rodent endemic to the afro-alpine grasslands of the Bale Mountains in Ethiopia. The species is an important ecosystem engineer with the majority of the global population found within 1000 km2. Here, we present the first complete mitochondrial genome of the giant root-rat and the genus Tachyoryctes, recovered using shotgun sequencing and iterative mapping. A phylogenetic analysis including 15 other representatives of the family Spalacidae placed Tachyoryctes as sister genus to Rhizomys with high support. This position is in accordance with a recent study revealing the topology of the Spalacidae family. The full mitochondrial genome of the giant root-rat presents an important resource for further population genetic studies.
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Affiliation(s)
- Victoria M. Reuber
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
| | - Alba Rey-Iglesia
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Michael V. Westbury
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Andrea A. Cabrera
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Nina Farwig
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
| | - Mikkel Skovrind
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Radim Šumbera
- Department of Zoology, University of South Bohemia, České Budějovice, Czech Republic
| | - Tilaye Wube
- Department of Zoological Sciences, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Lars Opgenoorth
- Department of Biology, Plant Ecology & Geobotany, University of Marburg, Marburg, Germany
| | - Dana G. Schabo
- Department of Biology, Conservation Ecology, University of Marburg, Marburg, Germany
| | - Eline D. Lorenzen
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
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Šumbera R, Lövy M, Marino J, Šimek M, Šklíba J. Gas composition and its daily changes within burrows and nests of an Afroalpine fossorial rodent, the giant root-rat Tachyoryctes macrocephalus. ZOOLOGY 2020; 142:125819. [PMID: 32750648 DOI: 10.1016/j.zool.2020.125819] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 06/27/2020] [Accepted: 07/02/2020] [Indexed: 01/12/2023]
Abstract
Fossorial mammals are supposed to face hypoxic and hypercapnic conditions, but such conditions have been rarely encountered in their natural burrow systems. Gas composition in burrows after heavy rains, deeper burrows and especially nest chambers, where animals usually spend most of the day, could be even more challenging than in shallow burrows. Such situations, however, have been rarely surveyed in the wild. In our study, we determined concentrations of O2, CO2 and CH4 in active burrows and nests of the giant root-rat Tachyoryctes macrocephalus, a large fossorial rodent endemic to the Afroalpine zone of the Bale Mountains in Ethiopia. We were able to determine the precise location of nests by tracking individuals equipped with radio-collars. To the best of our knowledge, this is the first study that analyses air samples taken directly from the nests of actually occupied burrow systems in any free-living fossorial mammal. We found no evidence for environmental hypoxia in the examined burrows and nests (range 19.7-21.6% O2). Concentrations of CO2 in the burrows increased after the burrows were plugged in the evening, but did not reach physiologically problematic levels. The highest CO2 concentrations in burrows were detected in the evening during a wet period (up to 0.44%). In root-rat nest chambers, the highest (but still harmless) CO2 concentrations (up to 1.31%) were detected in the morning (measured in the late dry season only) together with an elevated concentration (up to 13.5ppm) of CH4. Regular surface activity of giant root-rats, combined with the relatively large dimensions of their nest chambers and tunnels, and the absence of heavy soils, may contribute to harmless atmospheres within their burrow systems.
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Affiliation(s)
- Radim Šumbera
- Faculty of Science, University of South Bohemia, Czech Republic.
| | - Matěj Lövy
- Faculty of Science, University of South Bohemia, Czech Republic
| | - Jorgelina Marino
- Wildlife Conservation Research Unit, Zoology Department, University of Oxford, Oxford, UK
| | - Miloslav Šimek
- Biology Centre CAS, Institute of Soil Biology, České Budějovice, Czech Republic
| | - Jan Šklíba
- Faculty of Science, University of South Bohemia, Czech Republic
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Hrouzková E, Bernasová E, Šklíba J. Eavesdropping on a heterospecific alarm call in the giant root-rat (Tachyorytes macrocephalus), an important prey of the Ethiopian wolf (Canis simensis). J ETHOL 2019. [DOI: 10.1007/s10164-019-00618-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Šklíba J, Vlasatá T, Lövy M, Hrouzková E, Meheretu Y, Sillero‐Zubiri C, Šumbera R. The giant that makes do with little: small and easy‐to‐leave home ranges found in the giant root‐rat. J Zool (1987) 2019. [DOI: 10.1111/jzo.12729] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Šklíba
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - T. Vlasatá
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - M. Lövy
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - E. Hrouzková
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - Y. Meheretu
- Department of Biology College of Natural and Computational Sciences University of Mekelle Mekelle Ethiopia
| | - C. Sillero‐Zubiri
- Wildlife Conservation Research Unit Zoology Department University of Oxford Oxford UK
- Born Free Foundation Horsham UK
| | - R. Šumbera
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
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Vlasatá T, Šklíba J, Lövy M, Meheretu Y, Sillero-Zubiri C, Šumbera R. Daily activity patterns in the giant root rat (Tachyoryctes macrocephalus
), a fossorial rodent from the Afro-alpine zone of the Bale Mountains, Ethiopia. J Zool (1987) 2017. [DOI: 10.1111/jzo.12441] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. Vlasatá
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - J. Šklíba
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
- Institute of Entomology; Biology Centre CAS; České Budějovice Czech Republic
| | - M. Lövy
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Y. Meheretu
- Department of Biology; College of natural and computational sciences; University of Mekelle; Mekelle Ethiopia
| | - C. Sillero-Zubiri
- Wildlife Conservation Research Unit; Zoology Department; University of Oxford; Oxford UK
| | - R. Šumbera
- Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
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