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Figure 4 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 4. Male specimens of Celeus ochraceus (MCNA 5057) from the study area (above) and Celeus flavescens (MCNA 552) from Fazenda Canabrava, Augusto de Lima, Minas Gerais (below).

Figure 6 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 6. From left to right: specimens of Lepidocolaptes squamatus from Pedra Bonita, Minas Gerais (MCNA 4079), Morro do Pilar, Minas Gerais (MCNA 4480); and specimens of Lepidocolaptes cf. squamatus from Curral de Pedras, Minas Gerais (MCNA 4978, MCNA 5237) in frontal (A) and ventral (B) views.

Figure 3 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 3. Tails of three female specimens of Campylopterus calcirupicola (from left to right: MCNA 4977, MCNA 5050, MCNA 5190) from Curral de Pedras, Minas Gerais, Brazil.

Figure 2 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 2. Species rarefaction curve (continuous line) and estimation curve using the Chao1 estimator (dashed line) for the avifauna of Curral de Pedras, Minas Gerais, southeastern Brazil, using 226 MacKinnon lists.

Figure 5 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 5. From left to right: specimens of Sittasomus griseicapillus sylviellus from Santa Teresa, Espírito Santo (DZUFMG 630), Mariana, Minas Gerais (MCNA 1406), Santa Bárbara, Minas Gerais (MCNA 4147), Curral de Pedras, Minas Gerais (MCNA 4970, MCNA 4981, MCNA 5052); and specimens of Sittasomus griseicapillus reiseri from Janaúba, Minas Gerais (DZUFMG 3428), and Riacho dos Machados, Minas Gerais (MCNA 2523).

Figure 7 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 7. From left to right: specimens of Xiphocolaptes albicollis albicollis fromTrês Rios, Rio de Janeiro (MCNA 2061); intermediate specimens between X. a. bahiae and X. a. albicollis from Conceição do Mato Dentro, Minas Gerais (MCNA 2903) and Mariana, Minas Gerais (DZUFMG 6536); and specimens of X. a. bahiae from Curral de Pedras, Minas Gerais (MCNA 5203, MCNA 5204) in lateral (A) and dorsal (B) views.

Figure 1 in First avifaunal survey of a Cerrado dry forest enclave on the right bank of the São Francisco River, Minas Gerais, Brazil, with insights on geographic variation of some species

Figure 1. Map of the study area in South America (black dot) in the Cerrado biogeographic province and its position in relation to the Caatinga and the Chaco biogeographic provinces (A); detail of the study area at Curral de Pedras with tracks of the sampled trails (white lines) (B).

opencc-zeroSep 2021View details →

Aboveground net primary productivity in regenerating seasonally dry tropical forest: contributions of rainfall, forest age, and soil

Identifying factors controlling forest productivity is critical to understanding forest-climate change feedbacks, modeling vegetation dynamics, and carbon finance schemes. However, little research has focused on productivity in regenerating tropical forest which are expanding in their fraction of global area have an order of magnitude larger carbon uptake rates relative to older forest. We examined aboveground net primary productivity (ANPP) and its components (wood production and litterfall) over ten years in forest plots that vary in successional age, soil characteristics, and species composition using band dendrometers and litterfall traps in regenerating seasonally dry tropical forests in northwestern Costa Rica. We show that the components of ANPP are differentially driven by age and annual rainfall and that local soil variation is important. Total ANPP was explained by a combination of age, annual rainfall, and soil variation. Wood production comprised 35% of ANPP on average across sites and years, and was explained by annual rainfall but not forest age. Conversely, litterfall increased with forest age and soil fertility yet was not affected by annual rainfall. In this region, edaphic variability is highly correlated with plant community composition. Thus, variation in ecosystem processes explained by soil may also be partially explained by species composition. These results suggest that future changes in annual rainfall can alter the secondary forest carbon sink, but that this effect will be buffered by the litterfall flux which varies little among years. In determining the long-term strength of the secondary forest carbon sink, both rainfall and forest age will be critical variables to track. We also conclude that a detailed understanding of local site variation in soils and plant communities may be required to accurately predict the impact of changing rainfall on forest carbon uptake. Synthesis We show that in seasonally dry tropical forests, annual rainfall has a positive relationship with the growth of aboveground woody tissues of trees and that droughts lead to significant reductions in aboveground productivity. These results provide evidence for climate change – carbon cycle feedbacks in the seasonal tropics and highlight the value of longitudinal data on forest regeneration.

opencc-zeroNov 2022View details →

Data for: Phosphorus limitation of early growth differs between nitrogen-fixing and non-fixing dry tropical forest tree species

Tropical forests are often characterized by low soil phosphorus (P) availability, suggesting that P limits plant performance. However, how seedlings from different functional types respond to soil P availability is poorly known but important for understanding and modeling forest dynamics under changing environmental conditions. We grew four nitrogen (N)-fixing Fabaceae and seven diverse non-N-fixing tropical dry forest tree species in a shade house under three P fertilization treatments, and evaluated carbon (C) allocation responses, P demand, P-use, investment in P acquisition traits, and correlations among P acquisition traits. N-fixers grew larger with increasing P addition in contrast to non-N-fixers, which showed fewer responses in C allocation and P-use. Foliar P increased with P addition for both functional types, while P acquisition strategies did not vary among treatments but differed between functional types, with N-fixers showing higher root phosphatase activity (RPA) than non-fixers. Growth responses suggest that N-fixers are limited by P, but non-fixers may be limited by other resources. However, regardless of limitation, P acquisition traits such as mycorrhizal colonization and RPA were non-plastic across a steep P gradient. Differential limitation among plant functional types has implications for forest succession and earth system models.

opencc-zeroDec 2022View details →

Biophysic and socioeconomic drivers of burned area and carbon emissions from fires in the Pantropical tropical dry forests

The global burned area declined by nearly one-quarter between 1998 and 2015. Drylands contain a large proportion of these global fires but there are important differences within the drylands, e.g., savannas and tropical dry forests (TDF). Savannas, a biome fire-prone and fire-adapted, have reduced the burned area, while the fire in the TDF is one of the most critical factors impacting biodiversity and carbon emissions. Moreover, under climate change scenarios TDF is expected to increase its current extent and raise the risk of fires. Despite regional and global scale effects, and the influence of this ecosystem on the global carbon cycle, little effort has been dedicated to studying the influence of climate (seasonality and extreme events) and socioeconomic conditions of fire regimen in TDF. Here we use the Global Fire Emissions Database and, climate and socioeconomic metrics to better understand long-term factors explaining the variation in burned area and biomass in TDF at the Pantropical scale. On average, fires affected 1.4% of the total TDF' area (60,208 km2) and burned 24.4% (259.6 Tg) of the global burned biomass annually at Pantropical scales. Climate modulators largely influence local and regional fire regimes. Inter-annual variation in fire regime is shaped by El Niño and La Niña. During El Niño and the forthcoming year of La Niña, there is an increment in extension (35.2 and 10.3%) and carbon emissions (42.9 and 10.6%). Socioeconomic indicators such as land management and population were modulators of the size of both, burned area and carbon emissions. Moreover, fires may reduce the capability to reach the target of "half protected species" in the globe, i.e., high-severity fires are recorded in ecoregions classified as nature could reach half protected. These observations may contribute to improving fire management.

opencc-zeroJan 2023View details →

Successional and phenological effects on plant-floral visitor interaction networks of a tropical dry forest

1. Plant-pollinator interactions are fundamental to ecosystem functioning; however, the role that succession and phenology have on these interactions is poorly understood, particularly in endangered tropical ecosystems. In highly diverse ecosystems such as tropical dry forests (TDF), variation in water and food availability determines the life cycles of animal pollinators. Therefore, understanding patterns of flowering phenology and plant-pollinator interactions across seasons in successional environments is key to maintaining and restoring TDF. 2. We analysed the functional dynamics of plant-floral visitor interactions at the community level across a successional gradient in a Mexican TDF. We evaluated changes in the diversity of blooming plant species and floral visitors, phenological patterns, interaction network metrics, and beta diversity among early, intermediate, and late successional stages, between dry and rainy seasons. 3. We found a higher diversity of blooming plant species and a higher richness of animal species in the intermediate and late successional stages. Peak abundance of floral visitors overlapped with flowering peaks in the late successional stages, but this was not consistently the case in the early and intermediate stages. Plant-floral visitors networks differed in structure according to successional stage and season, but specialisation metrics were higher in late successional stages. Interaction networks were more dissimilar between dry and rainy seasons within successional stages than within seasons between successional stages, suggesting connectivity across successional sites during each season. In addition, closely related plant species do not share the same pollination systems in any successional stage. 4. Synthesis. Our results showed that plant-floral visitor interactions are dynamic and vary with flowering phenology and with successional changes in plant and animal diversity. Plant-floral visitor interactions were more diverse and specialised in the late successional stages. In the rainy season, differences in network structure among successional stages are due to interaction rewiring, while in the dry season, it is caused by species turnover. Our results demonstrate that seasonality plays a key role in community diversity and network structure and highlight the importance of conserving mature forests to ensure the maintenance of critical pollination interactions across all successional stages.

opencc-zeroJan 2023View details →

Data from: Leaf-cutting ant nests support less dense and impoverished seed assemblages in a human-modified Caatinga dry forest

Regenerating forests make up an increasingly large portion of tropical landscapes worldwide and regeneration dynamics may be influenced by leaf-cutting ants (LCA), which proliferate in disturbed areas and collect seeds for fungus culturing. Here we investigate how LCA influence seed fate in human-modified areas of Caatinga dry forest. We evaluate the seed deposition and predation on Atta opaciceps nests, foraging habitat surrounding nest and control habitat away of nest influence of 15 colonies located along a forest cover gradient during the rainy and dry season. For each habitat, four 50-cm2 plots were established and all seeds on the soil surface were collected along one year. We recorded 13,628 seeds distributed among 47 species and 36.57% of the total seeds did not show any sign of predation. Nest mound habitats supported low-density and species-poor seed assemblages, which were taxonomically distinct from the control habitats. These effects only occurred in the rainy season. The proportion of undamaged seeds were similar across the habitats. While forest cover did not influence seed assemblage in terms of species richness or seed predation, it did interact with habitat type via increments in seed abundance as forest cover increased across the nests. Forest cover also affected seed composition, but only in the rainy season. These results indicate that LCA decrease seed deposition in areas under their influence, particularly on the nest mounds. As LCA profit from human disturbance in the Caatinga, their role as seed 'sinks' should be enhanced in disturbed Caatinga patches, particularly during the rainy season, when most of the plant recruitment occurs. Our findings reinforce the importance of LCA as drivers of forest dynamics and resilience in human-modified landscape.

opencc-zeroDec 2022View details →

A new, disjunct species of Bahiana (Euphorbiaceae-Acalyphoideae): Phytogeographic connections between the seasonally dry tropical forests of Peru and Brazil, and a review of spinescence in the family

Bahiana is expanded from 1 to 2 species with the description of B. occidentalis K. Wurdack, sp. nov. as a new endemic of the seasonally dry tropical forests (SDTFs) of Peru. The disjunct distribution of Bahiana with populations of B. occidentalis on opposite sides of the Andes in northwestern Peru (Tumbes, San Martín) and B. pyriformis in eastern Brazil (Bahia) adds to the phytogeographic links among the widely scattered New World SDTFs. Although B. occidentalis remains imperfectly known due to lack of flowering collections, molecular phylogenetic results from four loci (plastid matK, rbcL, and trnL-F; and nuclear ITS) unite the two species as does gross vegetative morphology, notably their spinose stipules, and androecial structure. Spinescence in Euphorbiaceae was surveyed and found on vegetative organs in 25 genera, which mostly have modified sharp branch tips. Among New World taxa, spines that originate from stipule modifications only occur in Bahiana and Acidocroton, while the intrastipular spines of Philyra are of uncertain homologies.

opencc-zeroMay 2023View details →

Cactus height increases the modularity of a plant-frugivore network in the Caatinga dry forest

Cacti fruits are key resources to many frugivorous animals in Neotropical arid and semiarid regions. However, most studies have focused on a particular animal group or cacti species, but few have explored the overall interactions of such species at the community level. Here we monitored frugivory on five cacti species using camera traps that sampled diurnal and nocturnal interactions. We investigated the structure of interactions with bird, mammal, and reptile frugivores in the Brazilian Caatinga dry forest. We hypothesized that the height of cacti limit interactions with different types of frugivores, which would result in highly structured and modular interaction networks. In 2,929 camera-days, we recorded 23 vertebrate species feeding on cacti fruits, including seven new records, all determined to be primary seed dispersers. As predicted, the cacti-frugivore network was modular and non-nested, with the two shortest cacti species grouped in a module dominated by interactions with reptiles and non-flying mammals. The tallest cacti species were dominated by frugivory interactions with birds and had comparatively less interaction diversity than shorter cacti species. Our results support the contention that cacti are keystone species in semiarid ecosystems where they produce small-seeded fleshy fruits year-round.

opencc-zeroJun 2023View details →

Throughfall exclusion and fertilization effects on tropical dry forest tree plantations, a large-scale experiment

Across tropical ecosystems, global environmental change is causing drier climatic conditions and increased nutrient deposition. Such changes represent large uncertainties due to unknown interactions between drought and nutrient availability in controlling ecosystem net primary productivity (NPP). Using a large-scale manipulative experiment, we studied for 4 years whether nutrient availability affects the individual and integrated responses of aboveground and belowground ecosystem processes to throughfall exclusion in 30-year-old mixed plantations of tropical dry forest tree species in Guanacaste, Costa Rica. We used a factorial design with four treatments: control, fertilization (F), drought (D), and drought + fertilization (D + F). While we found that a 13 %–15 % reduction in soil moisture only led to weak effects in the studied ecosystem processes, NPP increased as a function of F and D + F. The relative contribution of each biomass flux to NPP varied depending on the treatment, with woody biomass being more important for F and root biomass for D + F and D. Moreover, the F treatment showed modest increases in maximum canopy cover. Plant functional type (i.e., N fixation or deciduousness) and not the experimental manipulations was the main source of variation in tree growth. Belowground processes also responded to experimental treatments, as we found a decrease in nodulation for F plots and an increase in microbial carbon use efficiency 25 for F and D plots. Our results emphasize that nutrient availability, more so than modest reductions in soil moisture, limits ecosystem processes in tropical dry forests and that soil fertility interactions with other aspects of drought intensity (e.g., vapor pressure deficit) are yet to be explored.

opencc-zeroAug 2023View details →

Temporal dynamics of soil fungi in a pyrodiverse dry-sclerophyll forest

Fire is a major evolutionary and ecological driver that shapes biodiversity in forests. While above-ground community responses to fire have been well-documented, those below-ground are much less understood. However, below-ground communities, including fungi, play key roles in forests and facilitate the recovery of other organisms after fire. Here, we used internal transcribed spacer (ITS) meta-barcoding data from forests with three different times since fire [short (3 years), medium (13–19 years) and long (>26 years)] to characterize the temporal responses of soil fungal communities across functional groups, ectomycorrhizal exploration strategies and inter-guild associations. Our findings indicate that fire effects on fungal communities are strongest in the short to medium term, with clear distinctions between communities in forests with a short time (3 years) since fire, a medium time (13–19 years) and a long time (>26 years) since fire. Ectomycorrhizal fungi were disproportionately impacted by fire relative to saprotrophs, but the direction of the response varied depending on morphological structures and exploration strategies. For instance, short-distance ectomycorrhizal fungi increased with recent fire, while medium-distance (fringe) ectomycorrhizal fungi decreased. Further, we detected strong, negative inter-guild associations between ectomycorrhizal and saprotrophic fungi but only at medium and long times since fire. Given the functional significance of fungi, the temporal changes in fungal composition, inter-guild associations and functional groups after fire demonstrated in our study may have functional implications that require adaptive management to curtail.

opencc-zeroAug 2023View details →

Data from: leaf functional diversity and environmental filtering in a tropical dry forest: comparison between two geological substrates

The role of geological substrate in shaping plant community functional diversity remains poorly understood. Considering the involvement of leaves in the energy, water and nutrient economics of plants, we hypothesized that leaves experience geology-related filtering, impacting functional attributes and functional leaf community diversity on different substrates. We studied tropical dry forest communities on limestone and siliciclastic phyllite-derived soils, comparing their functional diversity and soil physico-chemical properties. We predicted the most benign habitat (less severe filter) to be associated with higher leaf functional diversity and an acquisitive strategy prevalence, while the more stressful habitat should show conservative leaf traits and lower leaf functional diversity. We measured six traits in 31 common tree species (representing ~80% of community crown cover): leaf area, specific leaf area, leaf thickness, leaf dry matter content, petiole length, and leaf blade narrowness. Leaf functional diversity was assessed through the functional trait dispersion metric. Intraspecific functional variation was examined in 25 species shared between substrates. The limestone substrate was more fertile (higher phosphorous) with higher water retention, while phyllite had higher nitrogen and lower humidity. Principal component analysis segregated plots by substrate, with limestone plots being more clustered. Community leaf functional diversity was higher in the limestone forest. Most species examined showed inter-substrate trait differences in at least one leaf functional trait. The two substrates constituted distinct growth environments, with the more benign substrate associated to higher community functional leaf diversity. The intraspecific analysis revealed the prevalence of acquisitive traits in the more benign and more conservative traits in the more stressful habitat. This study advances our understanding of the role of geological substrate as an environmental filter in tropical dry forest, influencing leaf functional responses and emphasizing the importance of intraspecific functional variation.

opencc-zeroSep 2023View details →

Environment differentially affects the functional and phylogenetic structures of plant communities in a dry evergreen Afromontane tropical forest

Testing how local environmental conditions influence plant community assembly is important to understand the underlying mechanisms that promote and/or maintain biodiversity. Functional traits are used to find the broad spectrum of resource use strategies that plants use to respond to environmental variation. The patterns and drivers of plant community assembly through the lens of traits and phylogeny, however, remain to be studied in a uniquely biodiversity rich but poorly known fragmented dry Afromontane forest of Ethiopia. Here, we combined trait and community phylogenetic data from thirty sampling plots of 20 × 20 m size to determine the functional and phylogenetic structures and their drivers in a fragmented, human-dominated dry evergreen Afromontane forest. We found phylogenetic and functional clustering of plants in which the effect of environment was found to be trait specific. A weak phylogenetic signal for traits was detected suggesting that species resource use strategies may not be inferred using species phylogenetic distance. Additionally, we found functional traits to be weak in predicting species abundance distribution. Overall, while this study shows a non-random community assembly pattern, it also highlights the importance of deterministic processes being trait specific.

opencc-by-4.0Sep 2023View details →

Chronological dataset of soil respiration fluxes from a seasonally dry forest in Northwest México

Soil respiration data was acquired and analyzed as described in Vargas-Terminel et al.[1]. Briefly, soil respiration was obtained by measuring changes in CO2 concentrations with a portable soil flux system attached to a static chamber covering a portion of soil. Each measurement cycle in soil lasted 3 mins and was done monthly during a four-year period in 8 to 12 locations within three sites of tropical dry forest in Northwestern Mexico (a recent abandonment, a mid-secondary forest and an old-growth).  Also, simultaneous soil temperature and volumetric soil water content measurements were carried with a thermocouple thermometer and a soil moisture sensor, respectively. Finally, soil respiration flux was calculated with commercial soil data processing software.