Comparison of Catasetum bicolor and C. ochraceum (Catasetinae: Orchidaceae) habitat preferences: implications for their conservation

Abstract

Family Orchidaceae is widely recognized for its mutualistic relationship with their pollinators, however, the knowledge about the most diverse monocotyledonous group on the planet it is still limited. Here, we recognized the ecological requirements and modeled the habitat preferences for Catasetum bicolor and C. ochraceum (Subfamily: Epidendroideae). We used climatic and bioclimatic data along with species’ occurrences records in a) Principal Components Analysis (PCA) to screen for the most influential variables; and, b) a maximum entropy algorithm (Maxent) for habitat suitability modeling. Also, preliminary conservation status and probable priority areas for monitoring and conservation were identified. Both species differed in their habitat preferences as shown by the altitudinal range. Factors screened by PCA were associated to temperature (average, minimum, seasonality), solar radiation, and precipitation of the driest and warmest months. The variables that influenced the most in the modeling process for C. bicolor were solar radiation, temperature seasonality, and its annual range; while for C. ochraceum were the precipitation of the driest month and solar radiation. Areas with habitat suitable conditions were identified in countries (Brazil, Colombia, Costa Rica, Ecuador, Nicaragua, Panama, and Venezuela) and biomes (humid and dry tropical, and subtropical forests) with highly dynamic land cover changes. The studied species were found to be in an endangered status based on their area of occupancy (< 76 km2). However, considering their extent of occurrence (> 20000 km2), they are in a status of less concern. These findings may be relevant for future monitoring plans and planning for ex-situ and in-situ conservation strategies.