Seasonality determines bird abundance, richness, and diversity among contrasting forest environments in the Northern Pantanal

Abstract

Seasonally flooded ecosystems are comprised by heterogeneous vegetation mosaics (i.e., environments), wherein habitat availability and food resources are spatially and temporally variable. Overall, these factors determine the abundance, richness, and diversity of birds. To evaluate season-and environment-dependent bird abundance, richness, and diversity, we sampled understory birds along two seasons (dry and wet) in three forest environments, i.e., one semideciduous non-flooding forest (Cordilheira) and two evergreen flooding ones (Cambarazal and Landizal), in the northern region of the Pantanal. Birds were captured using mist nets that were located in four sites for each environment between 06:00 h and 11:00 h, during 3 months in the dry season and 3 months in the wet season. We captured 505 individuals from 21 families and 70 species of understory birds. Seasonality significantly affected bird composition, with higher abundance, richness, and diversity in the dry season. Indeed, most of the individuals were captured in the dry season (n = 365), comprising 62 species and 20 families. During the wet season, we captured 140 individuals from 38 species and 15 families. Although the Landizal, an evergreen flooding forest environment, comprised a number of individuals about 20 and 40% higher than the Cambarazal and the Cordilheira, respectively, we did not detect any significant difference in understory bird composition among environments. This study reinforces the assumption that seasonality determines understory bird abundance, richness, and diversity, which increase during the dry season, in the Pantanal. We suggest that this pattern is related to higher habitat and food resources availability during the dry season.

Knowledge gaps and biases in the Pantanal indicate future directions for ornithological research in large wetlands

“…Thus, abundance and behaviour may better capture some important characteristics of bird populations and communities facing seasonality in the Pantanal. Indeed, abundance is a well-documented measure to determine differences in bird populations between the dry and the flooding season in this biome (Pinho & Marini 2012, Thomas et al 2020. By contrast, process-related responses such as interspecific interactions (e.g.…”

“…Amazonia, Cerrado and Chaco) supplies diverse habitat and food resources, which ultimately determine the breeding season, abundance and diversity of birds (Pinho & Marini 2012, Pinho et al 2017, Thomas et al 2020. However, few studies have described the spatial and temporal dynamics of Pantanal bird communities (Figueira et al 2006, Donatelli et al 2017 or aspects related to behaviour, reproduction and conservation of species (Yabe 2009, Yabe et al 2011, Pinho & Marini 2012, Pinho et al 2017, Thomas et al 2020. In recent decades, the spread of pastures for cattle, soy production and the introduction of exotic species have increased the rates of fragmentation and native habitat loss in the Pantanal by about 11% (MapBiomas 2017, Tomas et al 2019).…”

“…In the Pantanal, seasonality coupled with the proximity of three major ecoregions (i.e. Amazonia, Cerrado and Chaco) supplies diverse habitat and food resources, which ultimately determine the breeding season, abundance and diversity of birds (Pinho & Marini 2012, Pinho et al 2017, Thomas et al 2020. However, few studies have described the spatial and temporal dynamics of Pantanal bird communities (Figueira et al 2006, Donatelli et al 2017 or aspects related to behaviour, reproduction and conservation of species (Yabe 2009, Yabe et al 2011, Pinho & Marini 2012, Pinho et al 2017, Thomas et al 2020.…”

Bird dependence on wetlands determines functional responses to flood pulse in the Brazilian Pantanal

“…However, the ecosystem functions of birds in wetlands are often overlooked due to the lack of essential information on their interactions in these environments (Green and Elmberg 2013). Some studies conducted in the Pantanal demonstrated the importance of environmental heterogeneity and seasonality for the diversity of plants (Catian et al 2018;Olivo-Neto et al 2020), mammals (Lázari et al 2013), birds (Deus et al 2020, Thomas et al 2020, snakes (Piatti et al 2019), anurans (Pansonato et al 2011), fish (Penha et al 2017) and invertebrates (Aranda and Aoki 2018;Battirola et al 2018). Nevertheless, due to recurrent environmental changes, there are still gaps in the understanding of events related to seasonality in species diversity (Tonkin et al 2017).…”

Effect of Flood Pulse on the Functional Diversity and Traits Composition of Birds With Different Degrees of Wetland Dependence in the Brazilian Pantanal

“…However, the ecosystem functions of birds in wetlands are often overlooked due to the lack of essential information on their interactions in these environments (Green and Elmberg 2013). Some studies conducted in the Pantanal demonstrated the importance of environmental heterogeneity and seasonality for the diversity of plants (Catian et al 2018;Olivo-Neto et al 2020), mammals (Lázari et al 2013), birds (Deus et al 2020, Thomas et al 2020, snakes (Piatti et al 2019), anurans (Pansonato et al 2011), fish (Penha et al 2017) and invertebrates (Aranda and Aoki 2018;Battirola et al 2018). Nevertheless, due to recurrent environmental changes, there are still gaps in the understanding of events related to seasonality in species diversity (Tonkin et al 2017).…”