At high stocking rates, cattle do not functionally replace wild herbivores in shaping understory community...

Area of Science:

• Ecology
• Rangeland Management
• Conservation Biology

Background:

• Livestock grazing impacts ecosystem structure and function globally.
• Cattle may functionally replace wild herbivores, but effects at high stocking rates are unclear.
• Interactions between cattle and wild herbivores can alter savanna vegetation dynamics.

Purpose of the Study:

• To evaluate if cattle at high stocking rates functionally replace wild herbivores.
• To test for interactive effects between cattle and wild herbivores on savanna understory vegetation.
• To understand how cattle stocking rates influence vegetation composition, diversity, and leafiness.

Main Methods:

• Long-term exclosure experiment in a semi-arid Kenyan savanna.
• Assessed herbaceous vegetation under varying cattle stocking rates (zero/moderate/high).
• Investigated effects in the presence and absence of wild mesoherbivores and megaherbivores.

Main Results:

• Herbivore identity, not total herbivory, determined community composition at high cattle stocking rates.
• High cattle stocking with wild mesoherbivores increased bare ground, annual grass, and diversity, while reducing perennial grass and leafiness.
• Megaherbivores modulated cattle impacts on composition and bare ground, but amplified effects on diversity.

Conclusions:

• Cattle at high stocking rates do not functionally replace wild herbivores in shaping savanna herbaceous communities.
• Interactions between cattle stocking rates and wild herbivore presence lead to non-additive vegetation responses.
• Findings have significant implications for wildlife conservation and livestock production in mixed-use rangelands.