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Highlights • Fever tree woodlands are important in the ecology and economics of tropical systems. • Fever trees stem size, crown cover and ground cover were evaluated. • Fever trees are resilient, but fever tree woodland crown and ground covers are vulnerable to disturbance. • Crown health of small fever trees respond negatively to wildlife disturbance. • Ground cover is less but more diverse in conservation areas while ground cover is more but less diverse in human disturbed areas. Abstract Losses of acacia woodlands have been reported throughout eastern and southern Africa. Of particular concern is the loss of fever tree (Vachellia xanthophloea) woodlands along the riparian areas of lakes which may result in the loss of important terrestrial and aquatic ecosystem services. For example, the Lake Naivasha basin in Kenya has endured considerable population growth and associated changes in land management with potential consequences for fever tree woodlands. This study assessed how fever tree woodland integrity differed with varying degrees of human and wildlife disturbances among surrounding land use management types. A field survey of fever tree woodlands suggest that land management types influenced degrees of human and wildlife disturbances, with settlement areas having significantly more human disturbance and conservation areas having significantly more wildlife disturbance. Furthermore, while land management type did not significantly influence the stem sizes of fever trees, it did influence the condition of woodland crown and ground covers. Settlement areas with high human disturbance were correlated with healthier crown covers (a possible artifact of the removal of dead or dying crown for fuelwood) while conservation areas with high wildlife disturbance were correlated with less healthy crown covers in smaller trees (<45 cm diameter at breast height) that were not killed but stunted by wildlife browsing. Settlement areas were dominated by more but less diverse ground cover while conservation areas were correlated with less but more diverse ground cover. While fever trees show resilience to multiple disturbances, the early warning of changes to the woodlands imply that the future of the fever tree woodlands is at risk and that limits to the encroachment of land management activities into the fever tree woodlands should be established. [ABSTRACT FROM AUTHOR]

Highlights • Tropical forests provide multiple benefits for surrounding human settlements. • Protection and conservation strategies safeguard carbon storage in undisturbed sites. • Previous authorized and ongoing unauthorized logging promote guava tree invasion. • Shift from non-guava to guava trees places multiple benefits including carbon at risk. • Enforcement of regulations and removal of guava trees needed to control their invasion. Abstract Tropical forests account for a substantial percentage of the world's carbon stocks, but the consequences to carbon storage of the rapid invasiveness of the guava tree in these forests is not known. Two different forest management strategies are practiced in a tropical forest in western Kenya: (1) a protection strategy where human entry is prohibited except for minimalistic human presence (e.g., research activities); and (2) a conservation strategy where human access to the forest and its resources are permitted. We assessed the effects of these management strategies and different levels of disturbance caused by the legacy effects of legal logging activities and the contemporary effects of unauthorized harvesting of forest products on the abundance of guava and non-guava trees and carbon storage in both plant biomass and soil in this forest. We found that guava trees were less likely to thrive and carbon storage in plants and soils was similar in sites with minimal disturbance under both the protection and conservation strategies. However, as disturbance increased, whether by the historical or contemporary effects of human activities, guava trees were more likely to thrive and carbon storage in plants shifted from non-guava trees to guava trees, but without an effect on more stable soil carbon. We conclude that regulations should be strictly enforced to prevent all logging activity, but the conservation strategy would provide similar effects on both forest plant and soil carbon to the protection strategy, while providing benefits to the surrounding community who rely on the forest for cultural and spiritual nourishment. [ABSTRACT FROM AUTHOR]