Agradecimentos: We thank the ICMBio for allowing us to work in Catimbau National Park. This project was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq PELD 403770/2012-2 and Edital Universal 470480/2013-0) and the Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE APQ 0738-2.05/12, APQ 0138-2.05/14, and PRONEX APQ 0138-2.05/14). This study is part of DHAM's PhD thesis as part of the Programa de Pós-Graduação em Biologia Animal (PPGBA-UFPE). DHAM acknowledges the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Finance Code 001, for a PhD scholarship. BKCF acknowledges the FACEPE for a post-doc grant (BFP-0141-2.05/21) and AVLF, MT and IRL for productivity grants (304291/2020-0, 310228/2016-6 and 305611/2014-3, respectively). AVLF also acknowledges support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2011/50225-3 and 2013/50297-0) and from the National Science Foundation (NSF DEB-1256742). This publication is part of the Rede Lep – Rede Nacional de Pesquisa e Conservação de Lepidópteros: SISBIOTA-Brasil/CNPq (Grant 563332/2010-7) Ver menos

Abstract: Anthropogenic disturbances and climate change are expected to reorganize biodiversity on multiple ecological levels from populations to ecosystems, especially in arid and semiarid regions due to environmental filtering imposed by water stress. This paper examines the individual and combined effects of chronic anthropogenic disturbance and increased aridity on the structure of fruit-feeding butterfly assemblages in a human-modified landscape of Caatinga dry forest, in the northeast of Brazil. Butterflies were recorded monthly across old-growth forest stands and their assemblages were described in terms of taxonomic and functional community-level attributes confronted to different levels of chronic disturbance and aridity. Butterfly assemblages were species-poor but had high species replacement (turnover) along both the chronic disturbance and aridity gradients. We observed a negative effect of aridity on alpha and beta diversity of butterfly assemblages. Butterfly assemblages across forest stands exposed to high levels of chronic disturbance and aridity had a nested structure. Functional diversity (Rao's Q) and the community-weighted means (CWM) of ocellus-bearing species and monocot-feeding larvae were negatively and positively affected by increased aridity and chronic disturbance, respectively. Our findings suggest that aridity and its combination with chronic disturbance have a drastic effect on the structure of butterfly assemblages in the Caatinga dry forest. These findings highlight that rainfall and chronic disturbances as major drivers of biological reorganization in human-modified landscapes. As aridity increases, Caatinga tends to support taxonomically and functionally impoverished and highly distorted assemblages Ver menos