Study Design

The study employs a replicated plot-based design to compare ecological conditions across three distinct management zones within Queen Elizabeth National Park.

Management Zones

🌾 Recently Cleared Sites

Areas where D. cinerea has been manually removed through uprooting and burning

🌳 Undisturbed Thickets

Dense D. cinerea thickets with no management intervention

🌿 Non-invaded Grasslands

Control sites representing natural savanna conditions

Plot Design

4 plots per site, each measuring 40 × 40 meters, used to collect soil samples and macrofauna data

Data Collection Methods

Soil Sampling

Soil samples collected at three depths: 0-10cm, 10-20cm, and 20-30cm

Macrofauna Collection

Methods based on the Tropical Soil Biology and Fertility (TSBF) protocol:

Pitfall Trapping
Sweep-netting
Visual Surveys
Soil Monolith Extraction

Preliminary Analysis Results

Key Statistical Findings

Soil Properties Analysis

PERMANOVA revealed significant multivariate differences in soil properties across Site × Depth combinations (F = 2.21, R² = 0.43, p = 0.001), while PCA indicated clear separation of soil fertility profiles along the invasion gradient.

Cleared Areas

Exhibited elevated exchangeable cations (K, Na, Mg), available P, and higher bulk density, reflecting short-term nutrient enrichment following the intervention.

Grassland Soils

Showed higher organic carbon and calcium content compared to other zones.

Undisturbed Thickets

Were nutrient-depleted, indicating the negative impact of D. cinerea invasion on soil fertility.

Macrofauna Diversity Results

Below-ground Richness

Grasslands supported the highest below-ground species richness (n = 17) and overall diversity

Undisturbed Thickets

Exhibited the lowest diversity across indices for below-ground macrofauna

Above-ground Richness

Was highest in thicketed areas but did not translate into higher overall diversity

Study Conclusions

Main Findings

Collectively, the findings indicate that Dichrostachys cinerea invasion suppresses soil fertility and below-ground biodiversity, and that manual uprooting combined with targeted burning partially restores edaphic conditions and supports macrofaunal recovery.

These results underscore the ecological value of low-impact, community-supported removal strategies for enhancing soil health and biodiversity in invaded African savannas.

Conservation Implications

  • Community-based manual removal is an effective restoration strategy
  • Short-term nutrient enrichment occurs post-intervention
  • Below-ground biodiversity recovers with management
  • Low-impact methods preserve soil ecological functions
  • Approach is scalable for other invaded African savannas

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