Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon Small forest losses degrade stream macroinvertebrate assemblages in the eastern Brazilian Amazon Janaina G. Brito a , F.O. Roque b,c , Renato T. Martins d, *, Jorge L. Nessimian e , Vivian C. Oliveira d , Robert M. Hughes f , Felipe R. de Paula g , Silvio F.B. Ferraz g , Neusa Hamada d a Secretaria de Educação do Estado de Matogrosso (SEDUC-MT), Colniza, Matogrosso, Brazil b Instituto de Biociências, Universidade Federal do Estado de Matogrosso do Sul, Campo Grande, MS, Brazil c Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Australia d Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia – INPA, Manaus, Amazonas, Brazil e Departmento de Zoologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil f Amnis Opes Institute and Department of Fisheries & Wildlife, Oregon State University, Corvallis, OR, United States g Laboratório de Hidrologia Florestal (LHF), Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, São Paulo, Brazil ARTICLEINFO Keywords: Aquatic insects Non-linear response Segmented regression Streams TITAN ABSTRACT Generally, habitat loss and fragmentation negatively afect biota, often in nonlinear ways. Such nonlinear re- sponses suggest the existence of critical limits for habitat loss beyond which taxa experience substantial changes. Therefore, we identifed change points for aquatic macroinvertebrate assemblages at both local-riparian and catchment extents in response to a forest-loss gradient in agriculture-altered landscapes of 51 small (1st to 3rd Strahler order) eastern Amazon streams. We used Threshold Indicator Taxa Analysis (TITAN) to identify change points for individual taxa and segmented regression analysis for assemblage richness. Considering the patterns of the cumulative frequency distributions of sum(Z - ) maxima across bootstrap replications, peak changes in macroinvertebrate assemblages were at ∼9% (5–95 percentiles = 1–15%) of forest-loss at the catchment extent, and at ∼1.4% (5–95 percentiles = 0–35%) of forest-loss at the local-riparian extent. Although the assemblage change point at the site extent was less than that detected at the catchment extent, the markedly lower percentile range indicates that biotic assemblages are more clearly responsive to forest-loss at the catchment/network- riparian extents than the site extent. For catchment and site extents, segmented regression analysis determined a change point for assemblage richness at 57% and 79% of forest-loss, respectively. This indicates the low capacity of total richness to separate early and synchronous decreases of sensitive taxa from gradual increases of tolerant taxa. Our results also show that it is not enough to focus management and conservation actions on riparian zones, but that conservation strategies should be expanded to entire catchments as well. The sharp decline of sensitive taxa in response to removal of a small portion of forest cover, even at catchment extents, indicates that the Brazilian Forest Code is insufcient for protecting stream macroinvertebrates. Consequently, we recommend strategies to reverse the potential collapse of aquatic biodiversity, particularly through avoiding deforestation and forest degradation, encouraging socio-economic incentives for restoring degraded areas, creating protected areas, and maintaining the current protected areas. We argue that reducing habitat loss should be a top priority for conservation planners in tropical forests because the sensitivity of aquatic biodiversity to removal of riparian forest-cover in Amazon rainforests is higher than previously thought. Therefore, the Forest Code regulatory framework needs complementary regulation that may be achived by more restrictive State and biome policies. 1. Introduction Agricultural activities performed over large areas cause extensive alterations in the landscape, mainly from conversion, loss, and frag- mentation of native vegetation (Laurance et al., 2014). These changes in the landscape signifcantly threaten ecosystem processes and biodi- versity, especially in highly diverse ecosystems such as tropical forests (Barlow et al., 2016). Recently, the expansion of agriculture and cattle grazing in the Brazilian Amazon has resulted in the loss of ∼18% of native forest (Ferreira et al., 2012). Moreover, such land use changes https://doi.org/10.1016/j.biocon.2019.108263 Received 6 May 2018; Received in revised form 12 September 2019; Accepted 20 September 2019 ⁎ Corresponding author. E-mail address: martinsrt@gmail.com (R.T. Martins). Biological Conservation 241 (2020) 108263 Available online 21 November 2019 0006-3207/ © 2019 Elsevier Ltd. All rights reserved. T