26th Annual Conference of the Botanical Society of Nigeria (BOSON) at
The Department of Plant Science and Biotechnology, Ekiti State University, Ado-Ekiti, Ekiti State, Nigeria.
Title: Distribution, Host Range and Habitat Characteristics of Thonningia sanguinea Vahl. (Balanophoraceae) in Southern Nigeria
by 1Imarhiagbe, O. and 2Aigbokhan E. I.
1. Faculty of Science, Edo University, Iyamho 2. Faculty of Life Science, University of Benin Introduction Distribution, host range, and habitat characteristics are significant factors in planning conservation strategy for parasitic plants (Marvier and Smith, 1997).
Parasitic plants (Kuijt, 1969; Musselman and Press, 1995; Heide-Jørgensen, 2008).
Thonningia sanguinea is a rare obligate holoparasitic plant endemic of forest trees (Bullock, 1948).
Thonningia sanguinea Thonningia sanguinea is a fleshy dioecious herb growing from an underground tuber.
The leaves lack chlorophyll.
It is dioecious, but some monoecious specimens have been observed.
The flowering stage is the only visible above ground part.
The crowded flower heads are Plate 1:Thonningia covered in scales (bracts) sanguinea plants. Male plant (top); female plant (Below)
JUSTIFICATION Thonningia sanguinea is endemic to tropical Africa and on which, to my knowledge, no recent ecological studies have been performed.
Beyond the visual occurrence of T. sanguinea on forest floors, little is known of its host range, distribution and habitat preference.
The cryptic nature of T. sanguinea and the fact that it has attracted little attention makes it imperative to conduct this research.
Aim and objectives Aim The aim of this study was to investigate the ecology of Thonningia sanguinea in Southern Nigeria.
Objectives Delineate the scope, range and distribution of T. sanguinea in Southern Nigeria.
Identify and elucidate its host range and preference
Characterize its habitat
Materials and Methods Table 1: Selected forested locations representing study sites S/N Study Area States Specific Locations
1 National Parks Edo Okomu National Park
Cross River Cross River National Park
2 Forest Reserves Ondo Ofosu Forest Reserves
Oyo IITA Forest Reserves
Ondo Idanre Forest Reserves
Osun Oba Hills Forest Reserves
3 Community Forest Edo Ehor nu wire
Edo Okuor
Edo Okokhuo
4 Plantation forest Edo Iyanomo
Figure 1: Map of Southern Nigeria showing study sites. (Inset: Nigeria Map)
Population Location Because of the cryptic and non-random nature of Thonningia sanguinea distribution within the forest environment, populations of T. sanguinea were located using:
Meander search
Published materials
Personal communication
The availability of local names for T. sanguinea in some ethnic groups. Sampling method Stratified sampling (Thorogood and Hiscock, 2007)
A 10 m x 10 m quadrat was used to accommodate the number of host trees present (Agianaku and Aigbokhan, 2018).
Host Location and Identification Excavation method was use to locate host plant
Taxonomic Identification of host and associated plant species were carried out using Floras (Hutchinson and Dalziel, 1927-1936), manuals (Keay, 1989), and Plate 2: Excavation process to checklists (Aigbokhan, 2014). reveal host connection
Distribution Reconnaissance studies by road were used to delineate the distribution of Thonningia in Southern Nigeria (Aigbokhan et al., 2010)
The distribution map of Thonningia was drawn with the ArcGIS software using data collected from the GPS readings of the various locations visited.
In order to fully understand the effects of other anthropogenic disturbance on this plant, oral interview were granted to the locals to determine the historical distribution of T. sangiunea.
Habitat characteristics Host type
Elevation: The elevation status per stand was recorded using a Garmin GPS device
GPS location/orientation (NS-EW): the location coordinate was recorded was recorded using a Garmin GPS device
Associated plant species
Soil type: Soil characteristics follows Hall,
(1977). Plate 3: some habitat characteristics monitoring gadgets
Results & Discussion
Figure 2: Potential and confirmed distribution of Thonningia sanguinea in Southern Nigeria Table 2: Habitat description and characteristics of Thonningia sanguinea Location Longitude Latitude Altitude Habitat description Soil type /Parent rocks (E) (N) (m)
Found growing on the edge of a Ferrallitic soils-central sub- Ehor Nu 0050 48.598 06018.342” 99.1 secondary forest. group less compact soil Wire Forest particles. Cenozoic sands
Present in large numbers Ferrallitic soils-central sub- Iyanomo 005034.898 060 09.746” 35.3 around stands of Hevea group less compact soil Forest brasiliensis. particles. Cenozoic sands
Ferrallitic soils-central sub-
group Coarse litter, with Secondary forest, comprising Okour partially decomposed plant 006004.928 060 11.962” 147.6 stands of Musanga cecropiodes Forest materials on soil surface. serving as host plant. Cenozoic sands
Location Longitude Latitude (N) Altitude Habitat location Soil type (E) (m) Parent rocks*
Idanre Colonies found in Theobroma Ferruginous tropical soil- Forest 005009.868 07001.954” 196.6 cacao plantation of the forest wet subgroup.. Basement Reserve reserve complex
Ofosu Found parasitizing Musanga Ferruginous tropical soil- Forest 005007.852 06043.278” 188.6 cecropiodes along nature trail, Dry sub soil group. Reserve forest interior Basement complex
Oba hills Ferruginous tropical soil- Along nature trail of the forest. Forest 004007.752 07045.275” 253.3 Dry sub soil group Host unknown. Reserve Basement complex
Ferruginous tropical soil- IITA Forest Along nature trail of the forest. 003053.530 07029.820” 214.5 Dry sub soil group. Reserve Host unknown. Basement complex
Location Longitude Latitude Altitude Habitat location Soil type (E) (N) (m) Parent rocks*
Ferrallitic soils-central 060 34.909” Secondary forest, largely sub-group. Cenozoic Okokhuo 0050 36.415” 21.0 dominated by stands of sands Hevea brasiliensis.
Found parasitizing mostly Ferrallitic soils-western Musanga cecropiodes,and Okomu sub-group, Coarse 060 21, 656” Myrianthus arboreus along National 0050 21.587” 10.2 litter, with partially nature trail in the forest. An Park decomposed plant indication of preference for materials on soil disturbed sites. surface
Parasitizing Host species Ferrallitic soils-South- along nature walk way in Cross eastern sub group. the forest. Some scattered River Fine litter, with fully 008026.438 05021.863” 139.2 on hard surfaces such as National decomposed organic rocks. Lophira alata was the Park material. Soil particles dominant host species in the highly compact. park.
Okomu National Park Okuor Forest Ofosu Forest Reserve
Cross River National Park Okomu National Park Plate 4: Habitat Preference of Thonningia sanguinea Table 3: Phytogeographical status of the host plant species of Thonningia sanguinea in Southern Nigeria S/n Host Plants Family Phytogeographic Life form Forest type status
1 Guarea cedrata Meliaceae Native Tree Secondary
2 Hevea brasiliensis Euphorbiaceae Exotic Tree Plantation
3 Lophira alata Ochanaceae Native Tree Secondary
4 Musanga cecropiodes Urticaceae Native Tree Secondary
5 Myrianthus arboreus Urticaceae Native Tree Secondary
6 Ricinodendron Euphorbiaceae Native Tree Secondary
heudelotii
7 Theobroma cacao Malvaceae Exotic Tree Plantation A B C
D E
Plate 5: Host species of T. sanguinea in Southern Nigeria (A): Ricinodendron heudelotii (B) Lophira alata (C) and (D) Myrianthus arboreus (E) Musanga cecropiodes A B
D E C Plate 6: Hautorium attachment in Thonningia (A, B, & C) Shows haustorial connection to host root (D) haustorium with multiple host root attachments (E) Thonningia sangunnea preference for Richinodendron as againstTrichilia monadelpha 35 31.57
30
host (%) host 26.31
25
20 occurrence of of occurrence 15 10.53 10.53 10.53 10
5.26 5.26 Percentage Percentage 5
0
Figure 3: Percentage occurrence of host plants in sites visited
14 14
12 10.5
10
8 7.25
6 5.2 4.25 4.34 4 3.15
2
0
Figure 4: Degree of infestation of Thonningia sanguinea on different host FINDINGS
The Findings from this study are as follows:
The physical presence of Thonningia was observed in 25 locations but records from folk taxonomy suggest a wider distribution range.
Thonningia sanguinea showed a broad host range with special preference for native trees and members of the Euphorbiaceae and Urticaceae.
The presence or absence of host plants appears not to be critical in the prevalence of Thonningia because even with the presence of host species, Thonningia was markedly absent in some areas.
FINDINGS cont.
However, host plants species were mostly located on the forest margins,where Thonningia sanguinea seemed to be very prevalent
T. sanguinea has a preference for disturbed areas of the forest preferably, areas along forest margins
Certain species were observed to show high frequency of association with Thonningia, they include: Allanblankia floribunda, Cleistopholis patens, Funtumia elastica, Harugana madagascariensis, Strombosia grandifolia, and Voacanga africana
Conclusion
The study has documented for the first time the range and scope of the distribution of Thonningia sanguinea in Southern Nigeria and also produced a comprehensive list of its host tree species.
The habitat preference suggests T. sanguinea as a good bio- indicator in predicting environmental insults in forested ecosystem.
Selected References • Aigbokhan, E. I., Osazuwa-Peters, O. L. and Ilubon, K.O. (2010). Range and distribution of Mimosa diplotricha in Nigeria and effects of fire on seed germination. Nigerian Journal of Botany 24 (1): 141-151
• Bullock, A. A. (1948). Thonningia Vahl. Kew Bulletin 3 (3):363-367.
• Thorogood, C. J., Rumsey, F. I. and Hiscock, S. J. (2009). Host specific races in holoparasitic Orobanhe minor: implications for speciation in parasitic plants. Annals of Botany 103: 1005-1014.
• Hall, J. B. (1977). Forest-types in Nigeria: An analysis of pre-exploitation forest enumeration data. Journal of Ecology 65 (1):187-199.
• Steentoft, M. (2008). Flowering Plants in West Africa. Cambridge University Press. pp. 1-350