Distribution and Ecology of Pectoral Antwren (Herpsilochmus pectoralis) and Caatinga Antwren (Herpsilochmus sellowi) in the Atlantic rainforest of Northeast Brazil

Abstract

The Pectoral Antwren (Herpsilochmus pectoralis) and Caatinga Antwren (H. sellowi) are Thamnophilidae endemic to Northeast Brazil. The Pectoral Antwren is considered an endangered species by the MMA (Brazilian Ministry of the Environment) and IUCN. The present study aimed at providing data on the distribution, abundance, habitat and conservation status of these species in Rio Grande do Norte state (RN), Brazil in order to help define conservation strategies and measures for the species. Thirty- three sites in the RN Atlantic Forest domain were sampled between November 2005 to March 2008, for a total sampling effort of 414 h. Observations took place mainly between 5h 30 min-12h 00 min, and records were based on visual and/or auditory contacts. Standardized censuses were conducted in four different phytophysiognomies to determine abundance and density. Herpsilochmus pectoralis was found in 73% (n = 24) of the sampled areas, mean density was estimated at ~102 individuals per km² and population size was approximately 66,000 individuals for the state. Available viable habitat was estimated at 504 km². Herpsilochmus sellowi was present in 39% (n = 13) of the areas, with mean density of ~47 individuals per km², estimated population of 14,700 and viable habitat of 312 km². These data widen knowledge of the species at local and national levels, in addition to confirming the importance of H. pectoralis in RN. The low number of conservation units in the region is alarming, given that privately-owned areas face fragmentation, selective deforesting, burnings and significant real estate development.