Ecosystem services in the Mariana Islands: implications of bird loss for a wild chili pepper species
Egerer, Monika H.
MetadataShow full item record
Birds play an important ecological role in tropical forests, yet the ecosystem services they provide to the world’s human community are less understood. In addition, forest birds are declining at an alarming rate, thus understanding the effects of ecosystem service loss on surrounding ecological and human communities is critical. Here, I use a natural experiment to elucidate the importance of birds in the maintenance of a culturally and economically important plant, the Donne’ Sali wild chili pepper (Capsicum frutescens Linnaeus) in the Mariana Islands. One island (Guam) has lost nearly all native forest birds due to an invasive snake, while three nearby islands (Saipan, Tinian and Rota) have relatively healthy bird populations. To determine whether bird presence is correlated with chili abundance, I surveyed similar forest on all islands for chilies. I systematically observed plants to link bird species to chili consumption and quantify chili frugivory by birds. To determine whether dispersal affects seed survival and germination, I monitored seeds placed adjacent to, and at varying distances from chili plants. Finally, to determine the importance of wild chilies for humans, I surveyed islands for items made from wild chili peppers. I found that Guam has reduced abundance and distribution of wild chilies in comparison to other islands, suggesting that birds are important for wild chili success. However, I did not find high frugivory by birds or strong distancedependent advantages of chili seed dispersal for seed survivorship and germination, so the link between birds and chilies is still correlative. Together, my results present support for the role and importance of birds for the ecosystem services they provide the local human community as wild chilies have an economic value. Future work can continue to investigate the mechanism(s) leading to the reduced abundance of chili peppers on Guam.