Bird surveys in grasslands: do different count methods present distinct results?

We compared two methods routinely used to conduct bird community surveys: point counts and transects. Our aim was to look for differences between these two methods regarding detection of bird richness and abundances. Additionally, we analyzed if one of the methods provided higher correlation of bird data with vegetation structure as an important habitat descriptor. From September 2014 to January 2015, we surveyed birds in 264 point counts and 258 transects spread across the southern Brazilian grasslands. We conducted one method in direct sequence of the other, in the same place with the same observers and at the same weather conditions. We standardized data to eliminate the effort bias caused by area covered and time employed in each method. Total abundance of birds recorded by the two methods did not differ (point counts 4753 and transects 4436, P = 0.31), but we found a significant difference in species richness (point counts 187 and transects 173, P = 0.01). Abundance of birds sampled with the transect method showed a slightly higher correlation with vegetation height (r2 = 0.07; P = 0.004) than the point counts method (r2 = 0.03; P = 0.05). While results from both methods were similar, richness detection was more effective in point counts, indicating that this method might be more useful than it currently is. We discuss potential factors that may influence effectiveness of both methods and suggest issues that should be addressed in further research in order to develop standardized sampling methods for bird communities

One hundred and thirty-five years of avifaunal surveys around Santarém, central Brazilian Amazon

We present an updated annotated avifaunal checklist for the Santarém region of central Pará state, Brazil, an area that has one of the oldest histories of ornithological exploration in South America. We combine data from a fivemonth quantitative survey of the birds of the municipalities of Santarém and Belterra (east of the Tapajós River) between 2010 and 2011 with an exhaustive search of material in museum collections worldwide and digital vouchers deposited online. Our own survey sampled habitats across a gradient of disturbance ranging from 'undisturbed' primary forest, through logged and burnt forest, patches of secondary forest, cattle pastures and intensive mechanized agriculture. Given the potential for species misidentifications in avian inventories, we paid special attention to obtaining voucher documentation. Here we present a collection of publicly accessible digital vouchers for all of the new species, in addition to providing museum catalogue numbers for all old records. We added 24 species to the regional list, principally species associated with anthropogenic land-uses, but also including seven species restricted to primary forest habitats which were missed from both recent published inventories and over the course of two centuries of intensive collecting efforts. The regional list now stands at 583 species for which voucher documentation is available, with an additional 26 undocumented species. Many of the species reported here are poorly known or represent notable range extensions, and we present new data on their status and distribution

A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazonia Sustentavel, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.Keywords: Social–ecological systems, Tropical forests, Land use, Interdisciplinary research, Sustainability, Trade-off

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Impact of Past Forest Fires on Bird Populations in Flooded Forests of the Cuini River in the Lowland Amazon

Blackwater floodplain forests of the Rio Negro are susceptible to understory fires. Bird composition was distinct between burned and unburned floodplain forest but not between young (12-18 yr) and old burns (>25 yr), indicating low resilience after fire. Forest regeneration is slow, with open grassy areas persisting >80 yr. © 2012 The Author(s) Journal compilation © 2012 by The Association for Tropical Biology and Conservation