Forest Resources and Wildlife Management

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Forest Resources and Wildlife Management

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Browsing Forest Resources and Wildlife Management by Author "Mlambo, D."

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    Effects of conspecifics and rocks on seedling recruitment of Brachystegia spiciformis Benth.in a dry miombo woodland in southern Africa
    (Elsevier, 2021) Mlambo, D.; Chiparange, F.T.
    Natural objects that buffer climate extremes and potentially function as regeneration niches are ubiquitous in dry miombo woodlands, yet few studies have explored their effects on early stages of plant recruitment. We used Brachystegia spiciformis to investigate the influence of conspecifics and rocks on early seedling recruitment in Cecil Kop Nature Reserve in Zimbabwe. B. spiciformis-dominated woodland was stratified into canopy and gap sites which were further divided into rock and rock-free microsites. In each microsite, we laid 3 blocks of 100 × 100 m and sow seeds of B. spiciformis in five 1 m2 plots close to rocks under canopies (CR), close to rocks in gaps (GR), rock-free in gaps (GF) and rock-free under canopies (CF), making a total of 60 plots. We laid additional 1 m2 plots to quantify the presence of naturally occurring seedlings at 1–12 m distances from boles of 15 trees in four cardinal directions. We found that photosynthetic photon flux density (PPFD), soil and air temperatures were significantly lower in CR, CF and GR than in GF while soil moisture displayed a reverse trend. Although seedling emergence was above 65% in all microsites, more than 60% of the seedlings died because of droughtrelated mortality which was increased in GF compared with other microsites. Survival probabilty of seedlings was highest in CF and CR, intermediate in GR and lowest in GF. Seedling biomass was increased in GR than under canopies despite higher concentrations of soil organic C, N and P in the latter. The density of naturally occurring seedlings was highest at the parent location than away from it, contradicting the Janzen-Connell recruitment pattern. We conclude that in dry miombo, conservation efforts may be well-served by focusing on the role of nurse objects in the plant recruitment process.
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    Mistletoe-infected trees facilitate invasion of the alien shrub Lantana camara in a semi-arid African savanna
    (Elsevier, 2024-07-18) Mlambo, D.; Mundava, J.
    The co-occurrence of mistletoes and Lantana camara (hereafter, lantana) is common in southern Africa, yet little is known about how they interact. To fill this gap, we investigated whether mistletoe-infected trees facilitate lantana invasion in a semi-arid southern African savanna. We compared invasibility, native woody plant diversity and soil parameters beneath mistletoe-infected and non-infected trees. We trapped bird droppings beneath mistletoe-infected and non-infected trees and conducted germination experiments to check if they contained viable lantana seeds. Regardless of whether trees were legumes or non-legumes, the subcanopy environments of mistletoe-infected trees had significantly higher invasibility than non-infected trees. The probability of lantana invasion beneath trees increased with mistletoe-infection levels. Soil nutrient concentrations were higher beneath mistletoe-infected trees than non-infected trees. Subcanopy invasibility was positively correlated with soil nutrient concentrations and negatively with native woody plant diversity. We found viable lantana seeds in bird droppings beneath mistletoe-infected trees. Put together, our findings indicate that mistletoes indirectly facilitate lantana invasion by enriching soil nutrients and attracting lantana seed dispersers. Our work provides a rationale for the necessity to simultaneously manage mistletoes and lantana where they cooccur to reduce invasion of the latter.
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    The coupling effects of pyrodiversity and land use on termite assemblages in semi-arid savanna
    (Elsevier, 2021-05-18) Ngwenya, B.T.; Ndagurwa, H.G.; Huruba, R.; Mlambo, D.; Mawanza, M.; Muvengwi, J.; MacFadyen, D.N.; Chirima, A
    Despite the importance of termites in the structure and function of savanna ecosystems, long-term studies that examine the effects of several disturbance factors on termite communities are limited constraining our understanding of determinants of termite assemblages in savanna. We determined termite assemblages in six random plots (100 m × 2 m) each established on no fire, low fire, and moderate fire frequency sites in a communal area and a commercial cattle-wildlife ranch in a semi-arid savanna, southwest Zimbabwe. Environmental variables i.e., soil and plant variables were also determined in the termite sampling sites. Relationships of land use, fire, and their interaction to (i) termite assemblage and (ii) soil and plant variables were tested using a general linear model (GLM). Relationships between termite assemblages and soil and plant variables were explored using canonical correspondence analysis (CCA). Nineteen termite species from three sub-families were present, dominated by Macrotermitinae. Termite species richness and abundance were greater by a factor of up to 2.8 in the ranch than in the communal area. Termite abundance and species richness only differed with fire frequency in the ranch, being greater at low fire frequency than at moderate fire frequency or no fire. Although some relationships were observed between the environmental variables and the composition of termite assemblages, the lack of differences in environmental variables between land uses and fire frequencies suggested that other factors may better explain the patterns in termite assemblages in this savanna.