Additive Effects Of Vertebrate Predators On Insects In A Puerto Rican Coffee Plantation

Abstract

A variety of studies have established the value of shaded coffee plantations as habitat for birds. While the value of birds as biological controls in coffee has received some attention, the interactions between birds and other predators of insects have not been tested. We used exclosures to examine the effects of vertebrate predators on the arthropods associated with coffee, in particular the coffee leafminer (Leucoptera coffeella) and the flatid planthopper Petrusa epilepsis, in a shaded coffee plantation in Puerto Rico. We used a 2 x 2 factorial design with four treatments: exclusion of birds, lizards, birds and lizards, and control (no exclusion). Abundance of insects > 5 mm increased when birds or both birds and lizards were removed. Birds and lizards had an additive effect for insects < 5 mm and for all insects combined. Coffee leafminers showed a weak response to removal of predators while planthopper abundance increased significantly in the absence of avian predators. Arthropod predators and parasitoids did not differ significantly between treatments. Our findings suggest that vertebrate insectivores have an additive effect on insects in coffee and may help control abundances of some coffee pests. Equally important, we present evidence suggesting that they do not interfere with other known natural enemies of coffee pests.

Avian Conservation Practices Strengthen Ecosystem Services in California Vineyards

“…Each of these factors may cause an underestimation of the effects of bird predation. Furthermore, overestimates may result from a faster reproduction rate of prey [36], which makes it difficult to assess the predation effect of a particular species, or even class of predator [37]. The CA winegrape growing season overlaps with the migratory bird breeding season when, due to the energetic demands of reproductive activities, the strongest predatory pressures occur [38].…”

Birds help plants: a meta-analysis of top-down trophic cascades caused by avian predators

“…Our four criteria excluded large numbers of articles, where cascading eVects on the plant level were not considered, even though they reported signiWcant eVects of the birds on their arthopod prey communities (e.g. Holmes et al 1979;Joern 1986;Fowler et al 1991;Floyd 1996;Borkhataria et al 2006). The 29 articles included in the meta-analysis had a total of 81 diVerent experiments or study set-ups, which were used as independent studies in the analysis.…”

Diet, microhabitat use, and thermal preferences of Ptychoglossus bicolor (Squamata: Gymnophthalmidae) in an organic coffee shade plantation in Colombia

“…Therefore, this kind of evidence might also provide a good arsenal for defending the value of natural ecosystems, especially when drastic habitat alteration as the cultivation of some crops is under consideration, as well as practices that combine biodiversity conservation with sustainable agricultural systems (Glor et al, 2001;Pianka & Vitt, 2003;Vitt et al, 2003b;Borkhataria et al, 2006). Organic farming or traditional shade coffee farming have shown to be a good model that unites biodiversity conservation with sustainable agricultural practices, not only because these plantations overlap with biodiversity hot-spots, but also because of their biological control of coffee pests (in contrast to other plantations as sun coffee plantations, where biodiversity is significantly lower than that of coffee shade plantations) (Hardner & Rice, 2002).…”

“…Since landscape, especially in altered environments, is a mosaic of patches and habitats along space, to understand how particular natural populations cope with to keep viable populations in human transformed habitats is of importance to the appropriated management and conservation of such populations. For all these reasons, understanding how species live in these modified systems is imperative (Perfecto et al, 1996(Perfecto et al, , 2003(Perfecto et al, , 2007Borkhataria et al, 2006).…”