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Conservation with elevated elephant densities sequesters carbon in soils despite losses of woody biomass
- Nature conservation and restoration in terrestrial ecosystems is often focused on increasing the numbers of megafauna, expecting them to have positive impacts on ecological self-regulation processes and biodiversity. In sub-Saharan Africa, conservation efforts also aspire to protect and enhance biodiversity with particular focus on elephants. However, elephant browsing carries the risk of woody biomass losses. In this context, little is known about how increasing elephant numbers affects carbon stocks in soils, including the subsoils. We hypothesized that (1) increasing numbers of elephants reduce tree biomass, and thus the amount of C stored therein, resulting (2) in a loss of soil organic carbon (SOC). If true, a negative carbon footprint could limit the sustainability of elephant conservation from a global carbon perspective. To test these hypotheses, we selected plots of low, medium, and high elephant densities in two national parks and adjacent conservancies in the Namibian component of the Kavango Zambezi Transfrontier AreaNature conservation and restoration in terrestrial ecosystems is often focused on increasing the numbers of megafauna, expecting them to have positive impacts on ecological self-regulation processes and biodiversity. In sub-Saharan Africa, conservation efforts also aspire to protect and enhance biodiversity with particular focus on elephants. However, elephant browsing carries the risk of woody biomass losses. In this context, little is known about how increasing elephant numbers affects carbon stocks in soils, including the subsoils. We hypothesized that (1) increasing numbers of elephants reduce tree biomass, and thus the amount of C stored therein, resulting (2) in a loss of soil organic carbon (SOC). If true, a negative carbon footprint could limit the sustainability of elephant conservation from a global carbon perspective. To test these hypotheses, we selected plots of low, medium, and high elephant densities in two national parks and adjacent conservancies in the Namibian component of the Kavango Zambezi Transfrontier Area (KAZA), and quantified carbon storage in both woody vegetation and soils (1 m). Analyses were supplemented by the assessment of soil carbon isotopic composition. We found that increasing elephant densities resulted in a loss of tree carbon storage by 6.4 t ha(-1). However, and in contrast to our second hypothesis, SOC stocks increased by 4.7 t ha(-1) with increasing elephant densities. These higher SOC stocks were mainly found in the topsoil (0-30 cm) and were largely due to the formation of SOC from woody biomass. A second carbon input source into the soils was megaherbivore dung, which contributed with 0.02-0.323 t C ha(-1) year(-1) to ecosystem carbon storage in the low and high elephant density plots, respectively. Consequently, increasing elephant density does not necessarily lead to a negative C footprint, as soil carbon sequestration and transient C storage in dung almost compensate for losses in tree biomass.…
Verfasserangaben: | Alexandra Sandhage-HofmannORCiDGND, Anja LinstädterORCiDGND, Liana KindermannORCiDGND, Simon AngombeORCiD, Wulf AmelungORCiDGND |
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DOI: | https://doi.org/10.1111/gcb.15779 |
ISSN: | 1354-1013 |
ISSN: | 1365-2486 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/34197679 |
Titel des übergeordneten Werks (Englisch): | Global change biology |
Verlag: | Blackwell Science |
Verlagsort: | Oxford [u.a.] |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Datum der Erstveröffentlichung: | 01.07.2021 |
Erscheinungsjahr: | 2021 |
Datum der Freischaltung: | 22.02.2024 |
Freies Schlagwort / Tag: | carbon sequestration; conservation; elephants; soil organic carbon; woody biomass |
Band: | 27 |
Ausgabe: | 19 |
Seitenanzahl: | 14 |
Erste Seite: | 4601 |
Letzte Seite: | 4614 |
Fördernde Institution: | Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG) [TRR 228/1] |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Peer Review: | Referiert |
Publikationsweg: | Open Access / Hybrid Open-Access |
Lizenz (Deutsch): | CC-BY-NC - Namensnennung, nicht kommerziell 4.0 International |