In his study  Effects of moisture and density-dependent interactions on tropical tree diversity , published in Nature, Dr. Edwin Lebrija-Trejos of the Biology and Environment Department shows that in central Panama plant diversity increased with soil moisture during the first year of life, persisting for over 15 years. Negative density‐dependent interactions among conspecifics were stronger in wetter years, contributing to increased diversity. Pathogens and phytophagous insects mediate interactions among seedlings in tropical forests, and many of these plant enemies are themselves moisture-sensitive. Changes in moisture availability caused by climate change and habitat degradation may alter these interactions and tropical tree diversity.