Arbuscular Mycorrhiza Fungi Communities and Associated Common Tree Species in Chawia, Fururu and Ngangao Forest Fragments of the Taita Hills Forest, Kenya

Abstract

Arbuscular mycorrhizal fungi (AMF) are forms of symbionts that are ubiquitous in natural ecosystems. They are crucial in maintaining plant communities by enhancing uptake of nutrient and water as well as acting as major drivers of seedling recruitment and sustainability. This research study intended to (1) To evaluate arbuscular mycorrhiza fungi status of common tree species, (2) To establish diversity of arbuscular mycorrhiza species and, (3) To determine arbuscular mycorrhiza propagules infectivity potential of the forest soils in selected forest fragments in Taita Hills. In circular plots of 15m radius, data on tree species, altitudes, levels of disturbances and fine root samples of seedlings of common tree species were collected. In addition, 500g of soil samples were collected 10cm of each circular plot at 30cm depth. Two grams of fine root samples of the common tree species were stained in trypan blue for morphological assessment and two hundred milligrams of the fine roots were grounded and Arbuscular mycorrhizal DNA exacted using Zymo plant/seed DNA extraction kit. One hundred grams of soil samples were extracted using wet sieving and decantation methods and the most probable number method was used in the assessment of Mycorrhizal infective propagules. The Mycorrhizal colonization status varied across eight tree species with colonization intensity ranging between 43.33% and 90.50%. Genetic diversity of AMF colonizing common tree species revealed a predominance of Glomus spp. The spore density of AMF in soils differed across forest fragments. The calculated Shannon diversity index across forest fragments ranged between 1.376 and 1.504 with no variation recorded in AMF diversity across forest fragments. Mycorrizal infective propagules differed significantly across forest fragments. Positive correlation between AMF diversity and tree diversity was recorded while altitudes negatively correlated with AMF diversity. Disturbances positively associated with AMF diversity. In conclusion, the selected tree species were mycorrhizal and the diversity of AMF in the Taita hills forest was within the recommended range of AMF diversity in tropical forests