Functional response of epiphytes in an enriching restoration

Epiphytes play a crucial role in natural ecosystems; however, their natural recolonization in areas undergoing ecological restoration is often slow and requires active restoration enrichments. This topic has been overlooked in ecological studies. This study aimed to evaluate the functional response of three epiphytes over a one-year sampling interval in two areas with distinct succession stages and standing forest structures (approximately five, and 20 years after restoration) in the environmental protection area of the São João hydrographic basin, Rio de Janeiro state. About 360 individuals (120 per species) of Araceae, Bromeliaceae, and Orchidaceae were studied. We measured six morphophysiological traits of all individuals, including specific leaf area, leaf dry matter content, relative water content, total chlorophyll (a and b) content, chlorophyll a/b ratio, and total chlorophyll/carotenoids ratio. Measurements were made at the beginning of the enriching restoration (October 2022), and every three months until the end of one year. Here we present the preliminary results from the first three months of monitoring (T0 and T1). Even for a relatively short evaluation period, multivariate ordination analyses revealed contrasting functional spaces occupied by individuals from each time, and area (five and 20 years of restoration). The multifunctional trait space became reduced for all species after three months for both areas, possibly due to the need to change traits that efficiently overcome more stressful environmental conditions. The most responsive traits were specific leaf area and chlorophyll content, which showed reduced values in the younger successional area. This suggested that excess light supply in this area may require a more conservative strategy than the initial condition of individuals. In this sense, the restoration enrichment of epiphytes in younger successional areas may require a pre-acclimatization phase to decrease functional changes during the process and, therefore, increase survival. We believe that our preliminary results are fundamental for a better understanding of the plastic capacity of epiphytes and, consequently, the improvement of epiphytic enrichment techniques.