September 2025: Paper of the Month by Lichtenberg et al -Enhancing Biodiversity in South Africa: Multi-Species Ecological Corridors Connecting Mega-Reserves for Conservation and Climate Resilience

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August 2025: Paper of the Month by Lichtenberg et al -Enhancing Biodiversity in South Africa: Multi-Species Ecological Corridors Connecting Mega-Reserves for Conservation and Climate Resilience

A recent study by Lichtenberg et al. (2025) titled “Landscape connectivity for biodiversity conservation: a mammal-based multi-species corridor approach for the Eden to addo corridor initiative, South Africa” published in Biodiversity and Conservation by Springer Nature reveals that 40 multi-species corridors connect South Africa’s mega-reserves, enhancing connectivity, guiding conservation, and informing protected area expansion.

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40 multi-species ecological corridors effectively connect South Africa’s mega-reserves, enhancing biodiversity, landscape connectivity, and conservation planning.– Lichtenberg et al. 2025

The study titled “Landscape connectivity for biodiversity conservation: a mammal-based multi-species corridor approach for the Eden to Addo Corridor Initiative, South Africa” aims to enhance biodiversity conservation by improving ecological connectivity across fragmented landscapes in South Africa. This research addresses the growing challenge of habitat fragmentation caused by urbanization and agriculture, with the goal of supporting national conservation initiatives such as the 30×30 plan and Vision 2040. To achieve this, the study models and identifies ecological corridors linking three major protected areas: Addo Elephant National Park (AENP), Baviaanskloof Mega-Reserve (BMR), and Garden Route National Park (GRNP). Using a multi-species approach, nine mammal species were selected as ecological indicators for their diverse habitat requirements and ecological roles: leopard, Cape grysbok, Cape mountain zebra, greater kudu, African elephant, bushpig, chacma baboon, bat-eared fox, and Cape clawless otter. These species represent different trophic levels and habitat preferences, offering a comprehensive perspective on ecological connectivity.

The study identified 40 potential ecological corridors ranging from 1.5 km to 53.6 km in length, primarily situated in areas with low to moderate human impact. Major barriers to connectivity include agriculture and road networks. While some corridors align with South Africa’s National Protected Area Expansion Strategy (NPAES), others reveal new opportunities for conservation action. The findings provide a practical framework for corridor planning at regional and national scales, emphasizing the importance of landowner participation, financial feasibility, and long-term management. Ecological corridors are also highlighted as tools to mitigate climate change impacts and facilitate species migration. The study’s limitations include a focus on mammals, which may not fully reflect the needs of birds, reptiles, or plants, and reliance on expert-based resistance mapping, which could be improved with GPS tracking and camera trap data. Future research should incorporate finer-scale ecological data, social dynamics, and land-use economics to strengthen corridor planning and biodiversity conservation efforts.

How the Study was Conducted

The study employed a structured, multi-step approach to model ecological connectivity across a large and ecologically diverse landscape in South Africa, specifically targeting the Eastern and Western Cape provinces, covering approximately 52,100 km². The focus was on three major protected areas: Addo Elephant National Park (AENP), Baviaanskloof Mega-Reserve (BMR), and Garden Route National Park (GRNP), with a 30 km buffer around each reserve to incorporate surrounding protected areas and potential corridor zones.

Nine mammal species were selected to represent diverse ecological roles, habitat preferences, and trophic levels. Selection criteria included ecological function (e.g., seed dispersal, predation), habitat specialization, trophic level, and expert input from regional conservationists.

To evaluate landscape permeability, resistance surfaces were developed for each species based on multiple environmental and anthropogenic factors, including land cover (SANLC 2022), human population density (WorldPop), road and rail networks (OpenStreetMap), topography (elevation, slope, roughness from SRTM), and proximity to water sources. Experts rated the influence of each feature on species movement on a scale of 1 (low resistance) to 100 (high resistance), and the averaged scores were used to generate species-specific resistance maps.

Connectivity modeling combined two complementary approaches. Least-Cost Path Analysis (using Linkage Mapper) identified the most efficient routes between habitat patches for each species, while Circuit Theory (using Circuitscape) simulated movement as electrical current, capturing multiple pathways and redundancy. The “all-to-one” mode was applied to model connectivity among all protected areas. Outputs from both models were rank-normalized and integrated to produce a multi-species corridor network, ultimately identifying 40 potential corridors ranging from 1.5 km to 53.6 km in length.

Corridors were further evaluated through land cover assessments to determine habitat composition and via the Human Footprint Index, which measured anthropogenic pressures using eight variables such as roads, croplands, and light pollution. Parcel-level mapping identified priority land parcels for corridor establishment, ensuring a minimum corridor width of 2 km to reduce edge effects.

Finally, resistance surfaces and model outputs were validated through expert review. Limitations of the study include the absence of GPS or camera-trap data, exclusion of non-mammalian taxa (birds, reptiles, and plants), and the lack of modeling of fencing impacts due to their variability across the landscape.

What the Authors Found

The authors found that 40 multi-species ecological corridors, varying in length and traversing largely low-to-moderate human impact landscapes, were identified to effectively connect South Africa’s three mega-reserves, revealing key areas for targeted conservation, enhancing landscape connectivity, and informing national protected area expansion.

Why is this important

Biodiversity Threats: Habitat fragmentation from agriculture, urbanization, and infrastructure isolates wildlife, reducing genetic diversity and increasing extinction risk.

Connectivity for Survival: Ecological corridors enable movement, migration, and adaptation, supporting gene flow, resource access, and climate resilience for wide-ranging species.

Strategic Conservation Planning: The study offers a replicable framework for identifying multi-species corridors, helping prioritize areas for protection and restoration.

Support for National and Global Goals: Aligns with South Africa’s Vision 2040, the 30×30 plan, and international biodiversity frameworks, promoting conservation targets.

Landowner and Policy Engagement: Parcel-level mapping facilitates collaboration with landowners, encouraging corridor establishment across public and private lands.

Climate Change Adaptation: Corridors allow species to shift ranges in response to climate change, acting as ecological lifelines under environmental stress.

Advancing Scientific Understanding: Demonstrates multi-species modeling applications in data-poor regions and highlights the value of expert-based resistance mapping.

What the Authors Recommended

• The authors advocate using multi-species modelling to identify connectivity hotspots, prioritize corridors, and align efforts with South Africa’s Vision 2040 and 30×30 goals.
• The study argues to establish corridors at least 2 km wide, utilize parcel-level mapping for land stewardship, and avoid highly urbanized or heavily farmed areas.
• The study emphasizes focusing on mammals for large-scale connectivity, including other taxa in future studies, and validating expert-based resistance mapping with GPS or camera trap data when possible.
• The study further advocates managing fencing impacts, promoting sustainable land-use practices, and restoring degraded or marginal farmland to enhance corridor functionality.
• In addition, collaborate with landowners and communities, address human-wildlife conflict, and explore financial incentives such as ecotourism, carbon markets, and nature credits.
• Furthermore, incorporate fire control, invasive species management, erosion mitigation, and riverine corridor protection, while refining modeling techniques and monitoring corridor effectiveness over time.

The study underscores that establishing multi-species ecological corridors is essential for enhancing biodiversity, supporting climate resilience, and guiding strategic conservation across South Africa’s landscapes.