Xymalos Monospora Research Articles

English

The study was aimed at contributing to sustainable management of Ajei Highlands Watershed Community Forest, one of the vulnerable and highly threatened biological hotspots remaining within the Cameroon western highlands through an analysis of its woody species diversity and stand structure. The results of inventory of its 12 gallery forest patches through 17 permanent sample plots (20 m x 50 m) with multiple spatial scales subplots (1, 10 and 100 m2) using Whittaker plot sampling method showed that a total of 3644 individuals  were recorded (124 species showing exclusive affinity to forest patches, 90 genera and 46 families). Diversity indices were 4.34 and 0.93 for Shannon-Weaver and Simpson indexes, respectively, indicating a highly diverse forest. The mean density was 1820 ± 24 stems/ha and the basal area 27.72 ± 0.04 m2/ha; with mean and maximum diameter of 9.3 and 140 cm, respectively. Species importance value index ranged from 0.35 to 35.19%, the most dominant species being Macaranga occidentalis, Xymalos monospora and Rauvolfia vomitoria. Euphorbiaceae, Apocynaceae, Moraceae and Rubiaceae were the most important families. Although this forest presented a high diversity and a certain floristic richness; few potentially commercial timber species were identified. Management options are prescribed within the framework of a participative management plan promoting watershed protection and habitat restoration, targeting livelihoods sustenance through agroforestry and reforestation activities favoring local tree species.   Key words: Woody diversity; watershed, gallery forest, community forest, Cameroon.

Production of an herbal green tea from ambang (Xymalos monospora) leaves: Influence of drying method and temperature on the drying kinetics and tea quality.

Decoctions of ambang (Xymalos monospora) leaves are claimed to have therapeutic potentials but they are seasonal and highly perishable because of its high moisture content. To improve on the use of this plant, drying studies were carried out on its leaves in an effort to produce a green tea. Green tea was produced under 3 different drying conditions including shade, sun and electric drying. The effects of drying method and temperature (50, 60 and 70°C) on the kinetics, proximate composition and total phenolic content of the teas were analyzed. Drying method had a significant effect on the drying kinetics and quality of the green tea produced. Drying occurred entirely in the falling rate period suggesting that the principal mechanism of drying was by diffusion. Kinetics of the drying processed were modeled successfully by the Page and Modified Page equations. Activation energy for the drying process as determined using K-values from the modified page equation was 27.89kJ/mol. Significant differences were observed in the quality parameters of teas produced. Protein, carbohydrate and total phenolic content were also dependent on the type of solvent used for extraction. The green tea produced at 60°C had most of its properties comparable to the commercial green tea used as a reference in the study. It is recommended that to produce good quality tea from ambang leaves, drying should be done at 60°C for 6h to obtain a tea with the following composition; moisture content (6.56 ± 0.01), total polyphenols (8.29 ± 0.08), Proteins (2.99 ± 0.13), ash (8.40 ± 0.15) and fiber content (20.43 ± 2.60).

Harvesting fodder trees in montane forests in Kenya: species, techniques used and impacts

There has been an increasing interest in fodder trees and their potential to help the rural poor. However, few studies have addressed the ecological impacts of fodder tree harvesting. We investigated the species harvested and the techniques used, and the effects of fodder harvesting on (1) species’ populations and (2) forest carbon stocks in three montane forests in Kenya. Focus-group discussions were organized in 36 villages to determine which species were harvested and with which techniques. Field observations were made on vegetation plots: stem diameter, tree height, species and extent of harvest were recorded. Carbon stocks were calculated using an allometric equation with (1) observed height of harvested trees, and (2) potential height estimated with a power model, and results were compared. Eight tree species were commonly harvested for fodder using different techniques (some branches, main stem, most branches except stem apex). Fodder harvesting (together with other uses for some species) negatively affected one species populations (Olea europaea), it did not negatively affect four (Drypetes gerrardii, Gymnosporia heterophylla, Pavetta gardeniifolia, Xymalos monospora), and more information is needed for three species (Olea capensis, Prunus africana, Rinorea convallarioides). Fodder harvesting did not significantly reduce forest carbon stocks, suggesting that local communities could continue using these fodder trees if a carbon project is established. Among the fodder species studied, X. monospora could be used in reforestation programs, as it has multiple uses and can withstand severe pruning. Although our study is only a snapshot, it is a baseline which can be used to monitor changes in fodder harvesting and its impacts related to increasing droughts in northern Kenya and increasing human populations.

Interactions between native tree species and environmental variables along forest edge-interior gradient in fragmented forest patches of Taita Hills, Kenya

Abstract Comparative investigations were undertaken in five forest fragments (Chawia, Fururu, Mbololo, Ngangao and Vuria) of varying sizes in Taita Hills, Kenya to examine the effects of forest edge on soil moisture, nitrogen, phosphorus, potassium, pH, electrical conductivity and organic carbon (hereafter referred to as environmental variables) along forest edge-interior gradient and relate them to tree species distribution and abundance. For each of the forest fragment, belt transects proportional to the forest area were established for data collection. Within each belt transect, plots of 10.0 × 10.0 m were systematically established and replicated three times in a stratum at an interval of between 10.0 and 50.0 m along forest edge-interior gradient depending on the size of the forest fragment for assessment of environmental variables and tree species distribution and abundance. Results showed significant edge effect on the distribution and abundance of dominant and adaptable tree species i.e. Macaranga conglomerata, Albizia gummifera, Syzygium guineense, Xymalos monospora, Tabernaemontana stapfiana and Maesa lanceolata (p = .012). Edge effect was also noted among the following environmental variables; soil pH in Mbololo (p

Diversity, Distribution, and Abundance of Plants in Lewoh-Lebang in the Lebialem Highlands of Southwestern Cameroon

A survey was conducted between October 2010 and June 2011 to determine the diversity, distribution, and abundance of plants in 4 sites of the Lebialem highlands and to relate species diversity and abundance to altitude and soil types. Twelve (12) plots, each of 1 ha (250 × 40 m), were surveyed at the submontane and montane altitudes of the sites. One hundred (100) species belonging to 82 genera were identified with the genera Cola and Psychotria being the most represented. Vulnerable species included Guarea thompsonii, Schefflera hierniana, Allanblackia gabonensis, Cyclomorpha solmsii, Vepris trifoliolata, and Xylopia africana. Species such as Xymalos monospora, Tricalysia atherura, and Piptostigma oyemense present in the study area were endemic to Cameroon. Diversity and distribution of plants were affected by parameters such as the altitude and the soil type. Soil analysis revealed that diversity in the study area was affected by the organic carbon, nitrogen, calcium, and the cation exchange capacity of the soil.

Avian fruit ingestion differentially facilitates seed germination of four fleshy-fruited plant species of an Afrotropical forest

Background and aims – The effects of gut treatment on the germination of animal-dispersed seeds are critical for the recruitment of many fleshy-fruited plant species, and hence for forest dynamics. However, these effects remain poorly studied especially in African plant species. In this paper, we aim to investigate the effects of gut treatment on the germination capacity and mean germination time of four common plant species of an Afrotropical cloud forest. Methods – We fed Xymalos monospora fruits to its three main avian dispersers to investigate different responses among frugivore species. Next, fruits of four plant species were fed to the most dominant avian disperser, Andropadus milanjensis, to compare responses among plant species. Germination capacity and mean germination time were compared among gut-passed seeds, manually depulped seeds and intact fruits. Key results – Germination of Xymalos monospora seeds was up to nine times more likely and almost twice as fast after bird ingestion compared to intact fruits. An increase in germination capacity, but not in mean germination time, was also detected in four sympatric plant species after ingestion by Andropadus milanjensis. The positive effects of seed ingestion on germination was mainly by fruit pulp removal; only one plant species showed an indication of the combined effect of fruit pulp removal and seed coat scarification on its germination success. Conclusion – Our results indicate that fruit ingestion of four common African forest plant species positively affected germination capacity and mean germination time, and that recruitment success of these plant species may therefore largely depend on their seed dispersers.

Tree species diversity, richness, and similarity between exotic and indigenous forests in the cloud forests of Eastern Arc Mountains, Taita Hills, Kenya

Biodiversity assessment for tree species was conducted in three forest fragments ofthe Taita Hills, southeastern Kenya to compare species diversity between and within three exotic forest plantations of pine, eucalyptus, cypress and the indigenous forests. The study sites were: Ngangao (120 ha), Chawia (86 ha), and Mbololo (185 ha). A Y-plot design was used to sample 32 plots comprising of 65 subplots. At each subplot, all juvenile trees of 5 cm and above in diameter at breast height (DBH) were enumerated and recorded by species. Tree regeneration (seedlings and saplings) was tallied by species. The Shannon-Weiner Index was used to calculate species diversity and evenness. The derived Shannon’s indices were further converted into effective numbers to show the magnitude of differences in species biodiversities. To evaluate differences in species diversities, a one way ANOVA was conducted and to separate the means, Tukey’s HSD and Duncan’s tests were used for even and uneven number of samples respectively. Jaccard’s similarity index was used to assess species similarities. There were more than 58 species whose stem densities varied between 10 and 2 000 trees per hectare. There were significant differences in species diversities between forest types and sites; the indigenous forests showed higher diversities than the exotic forests. Similarly, Chawia sites had higher species diversity than both Ngangao and Mbololo. Chawia also had a higher number of regenerated species than the two other sites, including species such as Xymalos monospora, Rapanea melanophloeos, and Syzygium guineense, which are associated with low levels of disturbance. These findings indicate that the indigenous forest is more diverse in species as would be expected in the tropics. The high species diversity in Chawia could be accounted for by the higher levels of disturbance it underwent, unlike the two other sites. The regeneration of species associated with low levels of disturbance found in the exotic plots of Chawia show the likelihood of presence of long-term soil seed banks. The low regeneration in the exotics plots observed in Ngangao and Mbololo are likely due to the absence of seed banks since some of the plantations were established on bare land (in Ngango), or the inherent physiology (allelopathy) of some of species repelling the regeneration of others.

Biogeography of the Monimiaceae (Laurales): a role for East Gondwana and long‐distance dispersal, but not West Gondwana

AbstractAim The biogeography of the tropical plant family Monimiaceae has long been thought to reflect the break‐up of West and East Gondwana, followed by limited transoceanic dispersal.Location Southern Hemisphere, with fossils in East and West Gondwana.Methods We use phylogenetic analysis of DNA sequences from 67 of the c. 200 species, representing 26 of the 28 genera of Monimiaceae, and a Bayesian relaxed clock model with fossil prior constraints to estimate species relationships and divergence times. Likelihood optimization is used to infer switches between biogeographical regions on the highest likelihood tree.Results Peumus from Chile, Monimia from the Mascarenes and Palmeria from eastern Australia/New Guinea form a clade that is sister to all other Monimiaceae. The next‐deepest split is between the Sri Lankan Hortonia and the remaining genera. The African Monimiaceae, Xymalos monospora, then forms the sister clade to a polytomy of five clades: (I) Mollinedia and allies from South America; (II) Tambourissa and allies from Madagascar and the Mascarenes; (III) Hedycarya, Kibariopsis and Leviera from New Zealand, New Caledonia and Australia; (IV) Wilkiea, Kibara, Kairoa; and (V) Steganthera and allies, all from tropical Australasia.Main conclusions Tree topology, fossils, inferred divergence times and ances‐tral area reconstruction fit with the break‐up of East Gondwana having left a still discernible signature consisting of sister clades in Chile and Australia. There is no support for previous hypotheses that the break‐up of West Gondwana (Africa/South America) explains disjunctions in the Monimiaceae. The South American Mollinedia clade is only 28–16 Myr old, and appears to have arrived via trans‐Pacific dispersal from Australasia. The clade apparently spread in southern South America prior to the Andean orogeny, fitting with its first‐diverging lineage (Hennecartia) having a southern‐temperate range. The crown ages of the other major clades (II–V) range from 20 to 29 Ma, implying over‐water dispersal between Australia, New Caledonia, New Zealand, and across the Indian Ocean to Madagascar and the Mascarenes. The endemic genus Monimia on the Mascarenes provides an interesting example of an island lineage being much older than the islands on which it presently occurs.

Spatial and temporal effects on recruitment of an Afromontane forest tree in a threatened fragmented ecosystem

Tropical forest fragmentation affects animal and plant populations in different ways. For plants, early stages (seed to seedling) are more sensitive to habitat alteration than adults, and can shape their future spatial patterns. Therefore, studying how seed germination and seedling growth and survival vary at different spatiotemporal scales enhances our understanding about plant recruitment in fragmented ecosystems. In this study we examine if, and to what extent, recruitment at early life-stages of Xymalos monospora (Monomiaceae), a bird-dispersed Afrotropical tree, differs between and within forest fragments that vary in size, surrounding matrix and microhabitats. Three years of field experiments (2004–2006) in south-east Kenya, revealed that patterns of seed germination and seedling survival and growth were largely inconsistent, both in space and time. Recruitment was not consistently higher in larger or less disturbed fragments. At smaller spatial scales within forest fragments, recruitment was subject to high between-year variation too, with decreased germination in gaps only in the dry year of 2004. However, performance of seeds and seedlings was consistently better away from than under conspecific fruiting trees. Our results imply that fragmented tree populations of X. monospora may become age-structured, or ultimately go extinct, if recruitment fails in subsequent years. This may especially affect populations in small, disturbed forest fragments, where seed dispersal and buffering against stochastic processes are generally reduced. Exotic plantations bordering indigenous forest fragments may provide suitable conditions for native tree recruitment; hence, forest expansion through enrichment planting should be considered in future conservation plans.

Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa

The Major Megetation Types (MVT) and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA) and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN). The resulting classification was further refined with table-sorting procedures based on the Braun–Blanquet floristic–sociological approach of vegetation classification using MEGATAB. Eight MVT’s were identified and described as Eragrostis lehmanniana var. lehmanniana–Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum–Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum–Combretum molle Blouberg Mountain Bushveld, Adansonia digitata–Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis–Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon–Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida–Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora–Rhus chirendensis Soutpansberg Forest Vegetation.

A Note on the Type of Paxiodendron ulugurense (Monimiaceae)

In tropical Africa the Monimiaceae are represented by two genera, Glossocalyx Benth. with four West African species, and Xymalos Baill. with one fairly widespread and variable species, X. monospora (Harv.) Warb. What appears to be one of the most unusual variants of X. monospora is that represented by the Kew isotype of Paxiodendron ulugurense Engl., which was reduced to synonymy by Verdcourt in Flora of Tropical East Africa, Monimiaceae (1968). This specimen was collected by Goetze (n. 274) in 1898 on the Lukwangule plateau of the Uluguru mountains, Tanzania, at an altitude of 2,400 m. Unfortunately this sheet consists only of fragments, and appears to be the only remaining material of this number; the holotype was destroyed in Berlin, and there is no other isotype at BR which has many of Goetze's collections (Bamps in litt.). The Kew material is remarkable in that, whilst the fruits are definitely those of a Xymalos, the leaves resemble those of Ocotea usambarensis Engl. As the fruits and leaves are separate on this sheet, it is quite possible that there has been a mix at some point, seeing that Ocotea usambarensis and Xymalos monospora grow together naturally. The Engler description mentions axillary racemes, so presumably the holotype consisted of more complete material than that sent to Kew, and it is almost certain that the specimen Engler described was a high altitude variant of Xymalos monospora with bullate leaves. However, in view of there being a possible mix in the Kew isotype, it is perhaps sensible to designate the fruits of the Kew sheet as the lectotype for Paxiodendron ulugurense, and ignore the leaves. It can now sink more conformably into Xymalos monospora.

The Rate of Forest Tree Growth and a Forest Ordination at Xumeni, Natal

The rate of increment in circumference at breast height of canopy tree species in the southern temperate, Mist-belt forest at Xumeni, Natal, South Africa, is very slow. The mean for all trees calculated from measurements in 1929 and 1966 is 0.201 ± 0.015 inches per year. Results from an ordination analysis of 39 plots were interpreted in terms of a successional gradient from serai sites on steep ground, characterized by Kiggelaria africana, Xymalos monospora and Fagara davyi, to climax sites on flatter ground with Podocarpus spp. Two climax types are indicated, with P. henkelli on moist soil and P. falcatus on drier soils.