Range, population estimates and conservation recommendations for Baillon's Crake, Allen's Gallinule, African Swamphen and Red-chested Flufftail in South Africa

Abstract

Africa’s herbaceous wetlands are vital ecosystems, which provide essential services such as water filtration, flood mitigation, and carbon sequestration, while supporting a diverse array of species, including Baillon’s Crake (Zapornia pusilla), Allen’s Gallinule (Porphyrio alleni), Red-chested Flufftail (Sarothrura rufa), and African Swamphen (Porphyrio madagascariensis). These species were chosen from the many that use wetlands as declines were inferred from citizen-science datasets and more detailed information was needed to aid in threat assessments for the IUCN Red Listing process. This study presents updated information on the distribution and population estimates of these four bird species in South Africa, utilising records from the BirdLasser mobile app and cross-verified with the Southern African Bird Atlas Project 2 (SABAP2) database. Species Distribution Modelling was conducted using MaxEnt, and South Africa’s 2020 Land Use and Land Cover dataset was employed to identify and delineate suitable herbaceous wetland habitats. By extracting the habitat from the predicted niche over 0.5 likelihood of suitability, results indicated an area of occupancy of 497 km2 for Baillon’s Crake, 173 km2 for Allen’s Gallinule, 3 574 km2 for Red-chested Flufftail, and 3 114 km2 for African Swamphen. Estimated home-range sizes allowed for projected maximum populations of 43 736 individuals for Baillon’s Crake, 17 128 individuals for Allen’s Gallinule, 1 588 444 individuals for Red-chested Flufftail, and 249 120 individuals for African Swamphen. This study highlights the critical importance of herbaceous wetlands for these species and underscores the significant threats posed by habitat loss and degradation, pollution, and climate change. Based on the range sizes, and degradation of suitable wetland habitat, it is recommended that Baillon’s Crake be considered regionally Endangered. Allen’s Gallinule occurs peripherally in South Africa and may potentially meet regionally Vulnerable under the IUCN Regional Red List criteria, when considering potential rescue effects from the more extensive extra-limital population stronghold. Conservation measures, including habitat protection and restoration, pollution control, climate-adaptation strategies, community engagement, and ongoing research and monitoring, are essential to safeguard these species and their habitats.