Landscape Simplification, Urbanization, Biological Invasions, and Climate Change: a Review of the Major Threats to Native Coccinellids in Central Chile

Coccinellids (Coleoptera) are important natural enemies of pests in agroecosystems. However, worldwide, native species face several threats, including landscape simplification, biological invasions, and climate change. In Central Chile, one of the global biodiversity hotspots, coccinellid communities are very diverse and are composed mostly of native species, which are most common in less disturbed habitats. In alfalfa fields, native coccinellids play a crucial role in the biological control of aphids, even when they are less abundant than exotics. However, in the last 2 decades, native species in this crop have declined in abundance and diversity. Our long-lasting field and laboratory studies have shown that this decline is associated with: (1) the invasion of Harmonia axyridis (Pallas), which has superior competitive abilities and escapes more from parasitism; (2) the simplification of agricultural landscapes, loss of natural habitats, and urbanization; and (3) increasing environmental temperatures and decreasing precipitation. The decline in native coccinellid populations has resulted in a loss of taxonomic and functional diversity of assemblages, which may jeopardize biological control. Alfalfa fields and natural and semi-natural habitats may offer an opportunity for the conservation of native coccinellids in agricultural landscapes. Such conservation might be achieved with better management of alfalfa fields and surrounding areas. Worldwide, native coccinellids (Coleoptera) face multiple threats. In Central Chile, coccinellid communities are diverse, with mostly native species. However, they have declined because of (1) invasion of Harmonia axyridis, (2) simplification of agricultural landscapes, natural habitats loss, and urbanization, and (3) increasing temperatures and decreasing precipitation. The decline in native coccinellids has resulted in lower taxonomic and functional diversity of assemblages, jeopardizing biological control. Alfalfa fields and natural and semi-natural habitats may offer an opportunity for their conservation in agricultural landscapes.image