TY  - JOUR
A1  - Irob, Katja
A1  - Blaum, Niels
A1  - Baldauf, Selina
A1  - Kerger, Leon
A1  - Strohbach, Ben
A1  - Kanduvarisa, Angelina
A1  - Lohmann, Dirk
A1  - Tietjen, Britta
T1  - Browsing herbivores improve the state and functioning of savannas
BT  - A model assessment of alternative land-use strategies
JF  - Ecology and evolution
N2  - Changing climatic conditions and unsustainable land use are major threats to savannas worldwide. Historically, many African savannas were used intensively for livestock grazing, which contributed to widespread patterns of bush encroachment across savanna systems. To reverse bush encroachment, it has been proposed to change the cattle-dominated land use to one dominated by comparatively specialized browsers and usually native herbivores. However, the consequences for ecosystem properties and processes remain largely unclear. We used the ecohydrological, spatially explicit model EcoHyD to assess the impacts of two contrasting, herbivore land-use strategies on a Namibian savanna: grazer- versus browser-dominated herbivore communities. We varied the densities of grazers and browsers and determined the resulting composition and diversity of the plant community, total vegetation cover, soil moisture, and water use by plants. Our results showed that plant types that are less palatable to herbivores were best adapted to grazing or browsing animals in all simulated densities. Also, plant types that had a competitive advantage under limited water availability were among the dominant ones irrespective of land-use scenario. Overall, the results were in line with our expectations: under high grazer densities, we found heavy bush encroachment and the loss of the perennial grass matrix. Importantly, regardless of the density of browsers, grass cover and plant functional diversity were significantly higher in browsing scenarios. Browsing herbivores increased grass cover, and the higher total cover in turn improved water uptake by plants overall. We concluded that, in contrast to grazing-dominated land-use strategies, land-use strategies dominated by browsing herbivores, even at high herbivore densities, sustain diverse vegetation communities with high cover of perennial grasses, resulting in lower erosion risk and bolstering ecosystem services.
KW  - browsing
KW  - ecohydrology
KW  - land use
KW  - plant community
KW  - savanna
KW  - wildlife
KW  - management
Y1  - 2022
U6  - https://doi.org/10.1002/ece3.8715
SN  - 2045-7758
VL  - 12
IS  - 3
PB  - Wiley
CY  - Hoboken
ER  -