Composition, spatial abundance, co-occurrence and host preference of mistletoes in the Central highland savanna of Namibia
| dc.contributor.advisor | Kwembeya, E. G. | |
| dc.contributor.author | Ondigo, Lilian K. | |
| dc.date.accessioned | 2025-10-30T14:10:23Z | |
| dc.date.available | 2025-10-30T14:10:23Z | |
| dc.date.issued | 2021 | |
| dc.description | A thesis submitted in fulfilment of the requirements for the Degree of Master of Science (By Thesis) | |
| dc.description.abstract | Aerial parasitic plants, commonly called mistletoes, are a polyphyletic group of organisms with a common evolutionary ancestor. This study was aimed at determining composition, spatial abundance within hosts, co-occurrence and host preference of mistletoes in the central highland savannas. The study site was divided into four sampling areas based on the presence of the distribution records of the species. Forty circular plots were demarcated and for every infested host plant species within these plots, canopy height, two diameter measurements at approximately 90", number of mistletoes, mistletoe species were recorded. All non-infested plant species within the plot were also identified and their abundances were recorded. Based on field records and herbarium records, four mistletoe species were identified and mapped namely; Oncocalyx welwitschii, Plicosepalus kalachariensis, and Tapinanthus oleifolius, belonging to the Family Loranthaceae and, Viscum rotundifolium which belongs to Family Viscaceae. A simple linear regression model established that canopy volume accounted for 12% of the variation in mistletoe abundance (R2 = 0.12, p < 0.001). However, canopy diameter was a better predictor of mistletoe abundance than canopy volume and accounted 20% of the variation in mistletoe abundance within the host canopy (R2 = 0.20, p = 0.0003). Canopy volume was a poor predictor because it might have included branches of various sizes even those that do not support mistletoe establishment. Also gaps within the host canopy as well as the extent and positioning of branches might have led to an overestimation of the actual volume of the host canopy that can potentially be infested by parasites. The results further revealed a statistically significant relationship between mistletoe abundance and vertical canopy position (x2 = 67.089, df = 6, p < 0.00 l) with most mistletoes occurring in the lower and middle third of the canopy of the host plant. The presence of V. rotundifolium and P. kalachariensis on the lower third of the canopy of the host plant could be explained by habitat preference and deposition behaviour of the Red faced mousebird ( Urocolius indicus). This means that the selection of this bird species for lower third of canopy for nesting and roosting, results in defecating of seeds more frequently on this part. On the contrary, the distribution ofT. oleifolius and 0. welwitschii in the middle third of the canopy could have been due to perch preference of the Yellow-fronted Tinker Barbets (Pogoniulus chrysoconus). It is possible they perch in the middle third of the canopy because there is a low risk of predation. Also, it could be that the branches in | |
| dc.identifier.uri | http://hdl.handle.net/11070/4182 | |
| dc.language.iso | en | |
| dc.publisher | University of Namibia | |
| dc.subject | Aerial parasitic plants | |
| dc.subject | Polyphyletic group | |
| dc.subject | Central highland savannas | |
| dc.subject | Namibia | |
| dc.subject | University of Namibia | |
| dc.title | Composition, spatial abundance, co-occurrence and host preference of mistletoes in the Central highland savanna of Namibia | |
| dc.type | Thesis |