Browsing by Author "Wanyama, Fredrick"

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    Does restoration success vary with tree size under restoration plantings and regrowth forests?
    (Conservation Science and Practice, 2022) Ssekuubwa, Enock; Goor, Wouter van; Snoep, Martijn; Riemer, Kars; Wanyama, Fredrick; Waiswa, Daniel; Yikii, Fred; Tweheyo, Mnason
    Several studies evaluate active (i.e., seeding/planting) and passive (i.e., protecting forest regrowth) restoration, but few studies examine successional patterns for different plant sizes. By using biodiversity and structure, we examined whether restoration communities approach old-growth forests over time, and whether restoration success varies for different tree sizes in both active and passive interventions. We examined how initial site conditions affect active restoration. Small (dbh ≥ 5 cm), medium (≥15 cm), and large trees (≥30 cm) were measured in 2003–2017 in permanent sample plots in restoration plantings (initially 3–8 years old) and in an old-growth forest in Kibale National Park, Uganda. Trees were also measured in regrowth forests (initially 16 years old) in 2011–2017. We collated information about site conditions from restoration reports. Biodiversity and structure increased over time towards the old-growth forest. Restoration plantings and regrowth forests recovered diversity and structure of small and medium trees except for large trees. Forest recovery increased with proportions of remnant banana plants and shrubs, while isolation from the old-growth forest slowed recovery. Disaggregating vegetation inventory data by tree size may be useful in achieving a holistic measure of restoration. Restorationists could prioritize sites with remnant banana plants and shrubs, and sites closer to old-growth forests in order to achieve better results.
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    Recovery of seedling community attributes during passive restoration of a tropical moist forest in Uganda
    (Applied Vegetation Science, 2021) Ssekuubwa, Enock; Goor, Wouter van; Snoep, Martijn; Riemer, Kars; Wanyama, Fredrick; Tweheyo, Mnason
    There has been a debate about the effectiveness of passive restoration for recovering tropical forests, but few studies quantify the success of passive restoration. The aim of this study was to better understand tropical forest succession under a passive restoration scenario. We compared floristic and functional attributes of seedlings in a passively restored and an old-growth forest, and assessed the effect of restoration age and distance from the old-growth forest on seedling attributes. Location: Kibale National Park, western Uganda. Methods: We measured seedlings in a passively restored and an old-growth forest in 2011, 2014 and 2017. We determined species diversity, structure and composition and searched the literature for functional traits. We used generalized linear mixedeffects models to compare seedling attributes between the restored and old-growth forest and determine the influence of restoration age and distance from the oldgrowth forest. Results: Seedling species abundance, evenness, basal area and height were similar between the restored and old-growth forest. Wood density and abundance of seedlings of different dispersal modes, habitat types, fruit size categories, and regeneration strategies were also similar between the restored and old-growth forest. However, richness, diversity and composition of seedlings were different. We found a positive effect of restoration age on species abundance and abundance of non-zoochorous, medium-fruited, forest-dependent, non-pioneer light demander and shade-tolerant species, and a negative effect on evenness, wood density, abundance of pioneers and compositional dissimilarity. Basal area of seedlings and the abundance of zoochorous and forest-dependent species declined while compositional dissimilarity increased with distance from the old-growth forest. Conclusions: Our results provide empirical evidence on the potential of passive restoration to recover the structure and functionality of tropical forests in a relatively short period of time. We demonstrate that the effect of restoration age and distance from the old-growth forest is not straightforward and depends on the attributes measured.