Chapter 11 Human Impacts on Pollination, Reproduction, and Breeding Systems in Tropical Forest Plants Mauricio Quesada, Fernando Rosas, Ramiro Aguilar, Lorena Ashworth, Víctor M. Rosas-Guerrero, Roberto Sayago, Jorge A. Lobo, Yvonne Herrerías-Diego, and Gumersindo Sánchez-Montoya Over the last two decades several studies have shown that plant species of contrasting life-forms ranging from small herbs to large trees may experi- ence a decline in reproductive success following habitat fragmentation and population disruption (Bawa 1990; Aizen and Feinsinger 1994; Aguilar et al. 2006). Such outcome has been shown for many plants throughout the tropics, particularly trees, where human activities have resulted in elevated rates of habitat fragmentation and degradation (Ghazoul and Shaanker 2004; Quesada and Stoner 2004; Quesada et al. 2004). Because almost 90 percent of angiosperms (i.e., lowering plants) depend on animals for effec- tive pollination and sexual reproduction (Buchmann and Nabhan 1996), it is of central concern to understand the capacity of pollinators for transfer- ring pollen among individuals and its consequences on plant reproduction in newly created anthropogenic landscapes. While evolutionary dependence of plants on animal mutualists for sexual reproduction has improved pollen transfer to stigmas, it has also prompted increased plant susceptibility to fragmentation and other forms of anthropogenic disturbance that characterize today’s landscapes (e.g., Ai- zen et al. 2002; Ashworth et al. 2004). Changes in abundance, composi- tion, and/or foraging behavior of pollinators as a consequence of habitat disturbance will have an effect on the amount and/or quality (autogamous DOI 10.5822/978-1-61091-021-7_11, © Island Press 2011 173 , R. Dirzo , Seasonally Dry Tropical Forests: Ecology and Conservation et al. (eds.)