Semi-traditional farm practices, integrated pest management, and sustainable livelihoods in the Andean Highlands of Venezuela

Traditional farming systems that conserve biodiversity often maintain pest populations in check by preserving the integrity of complex food webs. I used a participatory approach to explore the relationships between semi-traditional long fallow rotation practices, field management and landscape complexity, and invasive tuber pest and natural enemy establishment in potato ( Solanum tuberosum) agroecosystems of the Venezuelan Andes. Results from community-based arthropod monitoring revealed that, while long fallow rotation may not be an effective tuber pest management strategy, farm practices that promote paramo conservation or rotational-grazing can improve landscape complexity and concomitantly reduce tuber pest populations in potato fields. Furthermore, I found that field-scale management practices that improve soil fertility and reduce agrochemical application were most effective in reducing tuber pest establishment when surrounding landscape complexity was high.;In partial response to invasive tuber pest outbreaks, some farmers in the Venezuelan Andes complement their cultivation of imported seed-potato varieties with native varieties of Solanum tuberosum ss. andigenum. While widely perceived by Andean potato farmers to be "more resistant" to tuber pest damage; the role of native potato varieties in managing invasive tuber pest remains unclear. I assessed the susceptibility of a native variety, Imilla Negra cv., to damage from a key exotic pest, Tecia solanivora Povolny (Lepidoptera: Gelechiidae), and investigated how polyculture diversification of native and imported varieties influenced bottom-up and top-down pest impacts. Varietal diversification did not significantly increase natural enemy impacts, reduce tuber pest damage, or improve overall tuber yield. However, the native Imilla Negra variety was less susceptible to pest damage than two imported potato varieties, and natural enemies played an important role in suppressing tuber pests. My findings support local farmer knowledge regarding the heightened "pest-resistance" of native varieties and suggest that low intensity management practices may be key in promoting conservation biological control.;In the wake of recent shortages of imported seed-potatoes in Venezuela, the cultivation of native potatoes may represent an important resiliency strategy among potato producers to reduce input dependency, increase access to critical capital assets, and improve the achievement of livelihood goals. I used a sustainable livelihoods framework to quantitatively assess the direct and indirect linkages between native potato production, vulnerability reduction, and livelihood goal achievement. I found that native potatoes were directly linked with increased social capital, which indirectly was important in the diversification of livelihood activities and the development of sustainable production systems.