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|Title: ||Ecological and Political Implications of Conversion from Shade to Sun Coffee in Puerto Rico|
|Authors: ||Borkhataria, Rena Rebecca|
|Advisors: ||Jaime Collazo, Chair|
Martha Groom, Member
Marcia Gumpertz, Member
Harold Heatwole, Member
Robert Rice, Member
|Issue Date: ||10-Jan-2002|
|Abstract: ||Recent studies have shown that biodiversity is greater in shaded plantations than in sun coffee plantations, yet many farmers are converting to sun coffee varieties to increase short-term yields or to gain access to economic incentives. Through conversion, ecosystem complexity may be reduced and ecological services rendered by inhabitants may be lost. I attempted to quantify differences in abundances and diversity of predators in sun and shade coffee plantations in Puerto Rico and to gain insight into the ecological services they might provide. I also interviewed coffee farmers to determine the factors influencing conversion to sun coffee in Puerto Rico and to examine their attitudes toward the conservation of wildlife.
Avian abundances were significantly higher in shaded coffee than in sun (p = 0.01) as were the number of species (p = 0.09). Avian species that were significantly more abundant in shaded coffee tended to be insectivorous, whereas those in sun coffee were granivorous. Lizard abundances (all species combined) did not differ significantly between plantations types, but Anolis stratulus was more abundant in sun plantations and A. gundlachi and A. evermanni were present only in shaded plantations. Insect abundances (all species combined) were significantly higher in shaded coffee (p = 0.02). I used exclosures in a shaded coffee plantation to examine the effects of vertebrate predators on the arthropods associated with coffee, in particular the coffee leaf miner (Leucoptera coffeela) and the flatid planthopper Petrusa epilepsis, in a shaded coffee plantation in Puerto Rico. Treatments included exclusion of birds, lizards, birds and lizards, and no exclusion. I found that birds had a significant effect on the abundance of Petrusa epilepsis and on insects > 5 mm in length. Combined insect species abundance as well as abundance of insects 2-5 mm and 5-10 mm varied significantly by treatment and removal of both birds and lizards had a larger effect than the removal of either taxa alone. Vertebrate predators exerted little influence over the coffee leaf miner, nor did they appear to appear with the leaf miner's natural enemies, a complex of parasitoid wasps.
In the survey of 100 coffee farmers, I found that sun coffee was substantially more prevalent than shaded coffee, both in number of farms and in land area devoted to its production. The average sun coffee plantation was significantly larger than the average shaded plantation (p = 0.02). Reasons for conversion from shade to sun coffee included higher yields, recommendations by agronomists, and incentives from the government.
Farmers placed high conservation value on species that are rare or provide services to humans. Vertebrate insectivores were more diverse and abundant in shaded coffee and may provide a service to farmers by depressing total insect numbers and preventing outbreaks of the planthopper Petrusa epilepsis. Furthermore, they did not interfere with parasitism of the coffee leaf miner by parasitoid wasps. I conclude that governmental incentives for shaded coffee have a high probability of success, since coffee growers are highly dependent upon assistance from the government.|
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