Studies on Thonningia sanguinea vahl. (balanophoraceae) in Southern Nigeria: iii. Distribution, habitat characteristics and phytosociology

Abstract

Apart from the recognition of Thonningia sanguinea as a root parasite of forest trees, information on other aspects such as the nature of its population, habitat preference and distribution range in Nigeria has not been reported. Hence to delineate its presence and current distribution ranges, reconnaissance surveys were carried out across selected forested areas in Southern Nigeria. Records on habitat characteristics comprising host type, elevation, GPS location/orientation, companion plant species, and soil types were collected from sampling sites habouring the plant. This study reports the presence of T. sanguinea in the following locations with an accompanying number of population: Cross River National Park (13), Ehor Nu Wire Forest (3), Okokhuo Forest (3), Okour Forest (2), Iyanomo Forest (2), Okomu National Park (12), Idanre Forest Reserve (2), Ofosu Forest Reserve (3), Oba Hills Forest Reserve (2), IITA Forest Reserve (5), and Omo Forest Reserve (2). Analysis of its habitat features revealed its preference for disturbed habitats, particularly those along forest margins and nature trails, where sunlight reflection reaches the ground. T. sanguinea habitats were characteristically ferrallitic or ferruginous soil. Phytosociological analysis of T. sanguinea habitats showed a regular association with secondary forest indicator species such as Cercestis sp, Harugana madagascariensis, Anchomanes difformis, Musanga cecropioides, Strombosia grandifolia, Icacina trichantia, Myrianthus arboreus. Thus, based on habitat preference, T. sanguinea can best be described as a species that avoid a highly disturbed environment but show a preference for areas with minimal disturbance in a forested environment. Consequently, T. sanguinea could be a potential bioindicator in predicting environmental degradation in a forested ecosystem.

Keywords: Habitat characteristics, bioindicator, phytosociology, parasitic plant.