Anthropogenically driven spatial niche partitioning in a large herbivore assemblage

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• Human activities, including civil conflict and subsequent restoration efforts, profoundly impact species distributions and ecological interactions.
• Gorongosa National Park in Mozambique provides a unique case study for examining ecological shifts due to extreme disturbance and recovery.
• Understanding niche partitioning is crucial for predicting how species coexist and respond to environmental changes.

Purpose of the Study:

• To investigate changes in distribution patterns and spatial niche overlap of four key grazing herbivore species (buffalo, sable, waterbuck, zebra) in Gorongosa National Park.
• To compare pre-war and post-war ecological scenarios to assess the impact of disturbance and recovery on species interactions.
• To determine how altered population dynamics influence niche similarity and dissimilarity among sympatric grazers.

Main Methods:

• Utilized long-term aerial survey data to quantify species' range sizes and spatial niche overlap.
• Analyzed data from pre-war and post-war periods to establish temporal ecological changes.
• Focused on four specific herbivore species: buffalo (Syncerus caffer), sable (Hippotragus niger), waterbuck (Kobus ellipsiprymnus), and zebra (Equus quagga).

Main Results:

• Buffalo and zebra populations experienced drastic range reductions post-war, occupying only subsets of their historical distributions.
• Sable and waterbuck expanded into previously avoided habitats, with waterbuck doubling their pre-war range.
• Pre-war spatial overlap among the four grazers was high, indicating niche similarity; this overlap significantly decreased in the post-war period.

Conclusions:

• Anthropogenic disturbances, such as civil war and subsequent ecological restoration, lead to significant alterations in species distributions.
• Changes in population sizes and distributions following disturbance can result in altered patterns of niche similarity and dissimilarity among coexisting species.
• The findings underscore the dynamic nature of ecological niches and the importance of considering disturbance history in conservation and wildlife management.