Patterns of species richness and abundance among cactus communities receiving different rainfall levels in the semiarid region of Brazil

Abstract

Th is study examines the variation in cacti species richness and abundance among sites with diff erent average rainfall and soil types. We assessed a total of 3,660 individuals of six species of Cactaceae: Cereus jamacaru, Melocactus zehntneri, Pilosocereus gounellei, Pilosocereus pachycladus, Tacinga inamoena, and Tacinga palmadora. Th e greatest species richness and abundance of cacti were at locations with low rainfall and more clayey soils. Th e species studied diff ered in multidimensional representation, with some species being more positively related to soils with a higher proportion of fi ne particles (M. zehntneri and P. gounellei), while others were negatively related to soils with a higher proportion of coarser particles (T. inamoena) or positively related to areas with higher rainfall and vegetation cover (C. jamacaru and P. pachycladus). Th e diff erential responses of the species of Cactaceae studied in relation to the gradients analyzed demonstrates the need for more research into the relationship between cacti and environmental variables in semiarid ecosystems with high environmental heterogeneity.

Effects of topographic factors on distribution of cacti along an elevation gradient in Brazilian Caatinga

“…The species richness and abundance found here are similar to values reported by other studies carried out in the semi-arid region of Brazil (Rodal & Nascimento 2002;Barbosa et al 2007;Lacerda et al 2007;Parente et al 2010;Araújo et al 2012;Pereira et al 2012;Ferreira et al 2016). Although species richness was found to be similar to other studies, the five sampled species corresponded to 50% of the total richness of cacti species present in the semi-arid region of Brazil (Barbosa et al 2007), which likely reflects the high environmental heterogeneity of the mountain for the establishment of species with different habitat and condition requirements.…”

“…It has been suggested that cacti species can be used as indicators of environmental heterogeneity and that the distributions of different species reflect edaphic gradients (Ferreira et al 2016). The results presented here also indicate that cacti species can be used for the analysis of heterogeneity in the formation of microhabitats at small scales, with topographic factors (elevation, slope, soil depth, rockiness) being drivers of patterns of abundance and richness of species of Cactaceae.…”

Composition of Caatinga Species Under Anthropic Disturbance and Its Correlation With Rainfall Partitioning

“…It has thorny and herbaceous succulent plants that during dry periods lose their leaves in response to weather conditions (Beuchle et al, 2015;Queiroz et al, 2019) The Caatinga Domain has suffered intense anthropogenic action over time (i.e., deforestation, logging and implementation of agricultural crops), and today it is estimated that half of its original surface has already been modified (Schulz et al, 2016;Vieira et al, 2013). The climatic seasonality also affect the plant cover, promoting alterations on phytosociology, and the floristic composition of the domains (Ferreira et al, 2016).…”