New Publication: Effects of Wildlife Conservation and Land Use Intensification on Heterotrophic Soil Respiration and Temperature Sensitivity (Q10) in Semiarid Savannas

By Alexandra Sandhage-Hofmann (Project A01 Future Carbon Storage), Judith Lenzen (Bundesamt für Naturschutz), Katharina Frindte (University of Bonn), Simon Tuhafeni Angombe (Project A01 Future Carbon Storage) and Wulf Amelung (Project A01 Future Carbon Storage).

Abstract

Increasing global temperatures promote heterotrophic soil respiration (Rh) and subsequent carbon losses. In addition, greater variability in precipitation leads to more frequent rainfall following dry periods, resulting in a ’pulse’ of microbial activity and carbon release known as the Birch effect, especially in dry regions. But the effect of wildlife conservation and landuse intensification on Rh and Q10 in savanna systems is almost unknown. We hypothesized that i) the Rh pulse after rewetting (“Birch” effect) contributes notably to carbon losses in semi-arid regions, ii) conservation with increasing elephant numbers leads to higher Rh and lower Q10 values compared to rangeland and cropland, iii) modulated locally by habitat type (subcanopy, grass, bare patch), and iv) explained by microbial community composition. We sampled topsoils (0–10 cm) from different habitat types in high and low elephant density plots, croplands, and rangelands in savanna woodlands of the Zambezi region, Namibia. The samples were incubated at different temperatures (20-40° C) using a Respicond® apparatus. Microbial biomass and associated community composition were analyzed by DNA analysis. Immediately after rewetting, carbon losses were substantial and amounted to 200 g CO2-C day-1ha−1.

WEB Elephant Mudumu
Savanna soil’s vulnerability to climate warming is comparable between conservation and intensification but carbon losses due to warming will be highest under wildlife conservation with high elephant densities. Image: Alexandra Sandhage-Hofmann

High elephant densities had the highest Rh at 25° C (1.21 µg CO2 g-1h−1) relative to other land uses (mean 0.75 µg CO2 g-1h−1) and significantly higher qPCR copy numbers. Rh was similar under different habitat types. The mean Q10 value during the growing season was comparable under cultivation and high elephant density (∼2.3), exceeding fixed values of land surface models. Warming increased Rh from 0.6 µg CO2 g-1h−1 at 20° C by a mean factor of 2.6 at 40° C, with the highest increase at high elephant densities (factor 3.4). Generalized linear mixed models identified contents of nitrogen, silt, pH, and land use type as main predictor variables, explaining 57 % of Rh variability. We conclude that savanna soil’s vulnerability to climate warming is comparable between conservation and intensification but that carbon losses due to warming will be highest under wildlife conservation with high elephant densities.


Reference

Sandhage-Hofmann, A., Lenzen, Frindte, K., Angombe, A., Amelung, W. 2025. Effects of wildlife conservation and land use intensification on heterotrophic soil respiration and temperature sensitivity (Q10) in semiarid savannas, Geoderma,Volume 454, 2025,117171, ISSN 0016-7061, DOI

More CRC News

picture taken during a workshop on "future making"

Methodologies of Future-Making: Ethnographic Inquiry Through Play and Landscape in Marginalized Contexts

This study by Saymore Ngonidzashe Kativu (German Institute of Development and Sustainability, IDOS & Project B05 “Science Futures”), Glory Ernest Mella (Sokoine University), Castrow Muunda ...
Read More »
book cover of "enforcing the line" by katrin sowa

Enforcing the Line: An Ethnography of the Kenyan Border Regime

By Katrin Sowa (University of Cologne). This book analyses historic and contemporary border regime developments in East Africa, and draws a complex picture of borders ...
Read More »
small holder farming in tanzania

New Publication: Blending Traditions – Evaluating Indigenous Agricultural Practices Among Smallholders in Turiani, Tanzania

In this study, Denis Chomboko (IDOS), Theobald Theodory (Project C03 “Green Futures”), Michael Brüntrup (IDOS & Project B05 “Science Futures”), Venance Shilingi (Project B03 “Violent ...
Read More »
poster for a speakers tour event on green hydrogen in namibia to take place in cologne on 13 october 2025

Speakers Tour: Green Hydrogen from Namibia – A New Chapter of German Colonial History?

Mon | October 13th, 2025 | 19:00 (CEST) Green Hydrogen from Namibia – A New Chapter of German Colonial History? Speakers Tour, organized by Attac, ...
Read More »
CfP-Africa-under-Construction

New Publication Explores How Global Infrastructure Projects Reshape Territorial Governance and Sovereignty

In this chapter, Erblin Berisha, Franziska Sielker and Peter Dannenberg (Project C01 “Future in Chains”) examine how international infrastructure and development initiatives—such as China’s Belt ...
Read More »
Scroll to Top