Interviews with farmers suggest negative direct and indirect effects of the invasive green iguana (Iguana iguana) on agriculture in Puerto Rico

Abstract

Agricultural communities and crop production are negatively impacted by invasive species, with the effects of pathogenic fungi, parasitic insects and weedy plants being well studied. Mammals and birds are also recognized as impacting crops, but reptiles, such as non-native green iguanas ( Iguana iguana ), are typically not considered agricultural pests. Research on non-native green iguanas has largely focused on the lizard’s interactions with native species with little attention given to its impact in the agricultural landscape. We conducted semi-structured interviews with farmers from 20 farms in Puerto Rico to explore the effect of the invasive green iguana on the production of crops and how farmers manage impacts, if any. A total of 34 of 55 crop species reported by farmers were negatively affected by the green iguana. We found that green iguanas were absent from 20% of farms, did not consume crops in 10% of the farms and caused negative impacts in 70% of the remaining farms. Negative impacts included crop loss and infrastructural damage, which had behavioral, emotional, and economic effects on farmers. Specific outcomes of these effects were revenue loss, refurbishing costs, changes in crop selection, management costs and emotional stress. Farmers considered management strategies as mitigation measures that needed to be constant to produce any positive effects on crop yield. They reported use of mesh fencing, hunting, and domestic animals as attempts to reduce negative effects of green iguanas on crop production. Recognition of this species as an agricultural pest is warranted in Puerto Rico and perhaps elsewhere in its introduced range. Agricultural extension agents should consider providing guidance on strategies to reduce negative impacts of green iguanas including cultivating less susceptible crops when possible.