Impact of invasive vine management on native flora: a case study of Kew Botanical Garden.databases

Thesis Abstract

Invasive vine proliferation threatens native flora at Kew Botanical Garden by altering habitat structure, reducing native plant richness, and disrupting pollination networks, with management practices varying across seasonal campaigns and horticultural zones. This study aims to evaluate the effectiveness of integrated invasive vine management on sustaining and recovering native plant communities within the garden’s conserved beds, temperate glasshouses, and outer arboretum plots. Specific objectives are (1) to quantify changes in native species richness, abundance, and cover before and after implementation of vine control interventions; (2) to assess shifts in soil properties, light availability, and microhabitat conditions associated with vine removal; (3) to analyze the relationship between management intensity, timing, and restoration of native vegetation; (4) to identify operational constraints and stakeholder perceptions influencing treatment efficacy; and (5) to develop a evidence-based framework for best-practice vine management tailored to botanic gardens. The methodological design adopts a longitudinal quasi-experimental approach (before-after-control-impact) conducted over 24 months, integrating ecological surveys with social-technical assessments. The population comprises native vascular plant communities across five management zones within Kew and the surrounding buffer areas, with treatment plots (n=15) subjected to standardized vine removal and follow-up weeding, and control plots (n=15) maintained under routine horticultural practice. Data collection employs (i) floristic surveys recording species presence, abundance, and cover using Braun-Blanquet scales, (ii) soil sampling for organic carbon, moisture, pH, and bulk density, (iii) light interception measurements (PAR) and canopy openness, (iv) remote-sensing-derived vegetation indices (NDVI) at quarterly intervals, and (v) stakeholder interviews (n=30) and workshop observations to capture management perceptions. Instruments include standardized plant identification keys, calibrated PAR sensors, soil analysis kits, a structured questionnaire, and interview guides, with validation via pilot testing (n=6 plots) and test-retest reliability assessments (Cronbach’s alpha > 0.8 for survey items). Data analysis integrates quantitative and qualitative techniques descriptive statistics and Shapiro-Wilk tests for normality, mixed-effects models to test treatment effects on native richness and cover while accounting for spatial autocorrelation, multivariate ordination (canonical correspondence analysis) to relate environmental variables to species assemblages, regression analyses to link vine density reduction to floristic recovery, and ANOVA to compare soil and light variables across zones. The conceptual framework draws on the niche theory to interpret competitive release following vine removal, the restoration ecology paradigm for succession dynamics, and the disturbance–diversity relationship to explain community responses under varying management intensities. It also incorporates the social-ecological systems lens to integrate stakeholder inputs into practice. Anticipated findings include significant increases in native species richness and cover in treated plots, improvements in soil structure and light availability, and a move toward native-dominated plant assemblages within 12–18 months post-intervention, contingent on consistent follow-up weeding. Expected secondary findings encompass correlations between higher vine suppression intensity and accelerated native recovery, as well as identified operational barriers such as seasonal labor constraints, access restrictions in heritage-listed zones, and herbicide-use considerations. The study contributes to knowledge by transferring evidence-based vine management strategies to botanic garden contexts, refining restoration protocols for temperate horticultural settings, and elucidating the interplay between physical habitat restoration and plant community reassembly. The main conclusion posits that integrated vine management, when coupled with timely monitoring and adaptive follow-up weeding, yields measurable restoration of native flora and ecosystem function in a major botanical institution. Recommendations include institutionalizing annual vine suppression cycles aligned with phenology, implementing a standardized monitoring framework (including routine NDVI and floristic surveys), augmenting stakeholder engagement to sustain long-term maintenance, and developing a decision-support toolkit for prioritizing management in zones with high native biodiversity value. Further research directions suggest exploring the long-term resilience of regenerated communities under climate variability and expanding the framework to other botanical gardens with similar ecological and operational constraints.