Secondary Forest Fragments Research Articles

Vertical Stratification of Butterfly Assemblages Persists in Highly Disturbed Forest Fragments of the Brazilian Atlantic Forest

Vertical stratification is a property of forest habitats related to the differential distribution of organisms according to the variation in the conditions, from the understory to the canopy. Here, we aimed to test whether butterfly assemblages from highly disturbed forests maintain the pattern of vertical stratification. We hypothesized that degraded forests would not exhibit vertical stratification due to the low variation in the microhabitat conditions along the vertical gradient, resulting from the canopy openness. To test this, we sampled fruit-feeding butterflies with bait traps, alternately disposed between the understory and canopy of three secondary forest fragments in a very fragmented Atlantic Forest landscape, for one year. We found that the vertical strata differed in terms of species composition, with a high contribution by the nestedness component on the beta diversity spatial variation. The understory assemblages had a higher abundance and were more diverse than the upper stratum. We demonstrated that vertical stratification is maintained even in disturbed forests; however, this does not necessarily provide support for a good quality and functioning ecosystem in these habitats. The butterfly assemblages recorded here are a subset of the species pool that inhabits conserved remnants. Thus, even being represented by species commonly found in disturbed habitats, the dynamic of vertical stratification of assemblages remains.

Urban conservation and tree diversity: a case study in Parque Xokleng, Nova Veneza, Southern Santa Catarina

Urban forests can be defined as sets comprising vegetation fragments and isolated or grouped trees inserted in urban or peri-urban areas. Within this mosaic, urban fragments are important for biodiversity conservation. The aim of this study is to contribute to the knowledge about the structure of vegetation in an urban forest in the town of Nova Veneza, Santa Catarina, Brazil. The study was conducted in the Parque Natural Municipal Xokleng (PNMX). A phytosociological survey was conducted in the forest, using the plot method, in which 30 continuous plots of 10 m x 10 m were established. We considered a tree every individual that had a diameter at breast height greater than or equal to 5 cm. In this study, 497 individuals belonging to 75 species and 32 families were sampled, along with 14 dead individuals, three individuals identified only at genus level, and one unidentified individual. The species with the highest importance values were Tetrorchidium rubrivenium, Machaerium stipitatum, Ficus adhatodifolia, Cabralea canjerana, Mollinedia triflora. The vegetation structure is similar to the structure observed in other secondary forest fragments in the southern region of Santa Catarina. The presence of secondary species in the canopy and with high dominance values reflects the regeneration process the forest is undergoing.

EFFECT OF FUNCTIONAL STRATEGIES AND ABUNDANCE OF Acacia mangium Willd ON THE NUMBER OF NATIVE SPECIES IN A SECONDARY FOREST FRAGMENT IN SOUTHERN AMAPA, BRAZIL

Acacia mangium Willd is a fast-growing exotic tree that, when inserted in a different environment, can present an invasive potential in secondary forests. This study aimed to analyze the effect of abundance and functional strategies of A. mangium Willd and edaphic factors on native species richness in a secondary forest fragment located behind the Instituto Federal do Amapá campus Laranjal do Jari, Amapá. For this, all tree individuals with diameter at breast height (DBH) ≥ 10 cm occurring in 10
 plots of 200 m2 distributed in the fragment were identified. Soil samples were collected in the plots and sent for fertility and granulometry analysis. Three leaf functional attributes of individuals of A. mangium Willd occurring in the plots were measured: leaf area (LA), leaf thickness (LT) and specific leaf area (SLA). A total of 145 tree individuals and 14 species were sampled, with A. mangium Willd being the most abundant with 95 individuals. The relative abundance of A. mangium Willd was negatively related to native species richness in the fragment. The species also exhibited distinct leaf attributes and abundances according to the variation in soil acidity and fertility in the fragment, which influenced the number of native species. There is a need to develop monitoring and management of invasive exotic species such as A. mangium Willd in fragments of secondary forests, since the species is invasive and opportunistic, and can inhibit the regeneration of native species after local disturbances.

Impacts of a severe storm on carbon accumulation in coarse woody debris within a secondary Atlantic Forest fragment in Brazil.

The alarming increase in extreme weather events, such as severe storms with torrential rain and strong winds, is a direct result of climate change. These events have led to discernible shifts in forest structure and the carbon cycle, primarily driven by a surge in tree mortality. However, the impacts caused by these severe storms on the production and carbon increment from coarse woody debris (CWD) are still poorly understood, especially in the Brazilian Atlantic Forest. Thus, the goal proposed by the study was to quantify the CWD volume, necromass, and carbon stock before and after the occurrence of a severe storm and to determine the importance of spatial, structural, and qualitative variables of trees in the CWD carbon increment. The increase in carbon by the storm was 2.01 MgC ha-1, with a higher concentration in the CWD less decomposed and smaller diameter class. The forest fragment plots showed distinct increments (0.05-0.35 MgC), being influenced by spatial (elevation, declivity, and slope angle) structural (basal area) and qualitative factors (trunk quality and tree health), intrinsic to the forest. Thus, it is concluded that severe storms cause a large increase in carbon in CWD, making it essential to understand the susceptibility of forests to the action of intense rains and strong winds to model and monitor the future impacts of these extreme weather events on Atlantic Forest and other tropical forests in the world.

Coarse woody debris dynamics in a secondary Atlantic Forest fragment in Brazil

The Atlantic Forest fragments have suffered from the impacts of climate change, resulting in the increased production of coarse woody debris (CWD), which needs to be evaluated in space and time to generate accurate estimates of carbon accumulation. Thus, the goals of this study were (i) to quantify the CWD volume, necromass, carbon stock, and annual increment of carbon (AIcarb) over a period of 4 years; and (ii) to select the optimal combination of climatic, topographic, edaphic, and intrinsic forest variables to accurately predict AIcarb using machine learning and multivariate analysis. The CWD volume, necromass, and carbon stock increased between 2017 and 2020. The AIcarb was 1.09 MgC ha−1 year−1 (2017–2018), 1.24 MgC ha−1 year−1 (2018–2019), and 2.31 MgC ha−1 year−1 (2019–2020). Statistical analysis indicated that climate variables had greater weight in the CWD carbon increment in the 2018–2019 and 2019–2020 periods, while edaphic, topographical, and intrinsic forest variables were more important for the 2017–2018 period. Our findings showed that the carbon increase in CWD was linked to temporal and spatial variables within forests. These results demonstrate the importance of this parameter in the carbon cycle of forest ecosystems and highlight that there should be greater international research efforts to quantify this carbon pool.

Floristic and phytosociological study of an urban fragment of secondary Amazonian forest in Capitão Poço – PA

Secondary forests constitute important regenerating areas and they are expanding rapidly in the Amazonian landscape. The characterization of forest remnants provides essential information for conservation, management and recovery actions. The objective of the present study was to conduct a floristic and phytosociological evaluation of an urban fragment of secondary Amazonian forest (8.12 ha) in Capitão Poço, Pará. Trees with DBH ≥ 3.2 cm were inventoried in five 15 m x 30 m plots. The floristic diversity, importance value, and diametric distribution were investigated. In the survey, 236 individuals from 23 species were recorded. The floristic diversity index was 2.58. The most important species were Cecropia obtusa Trécul and Lacistema pubescens Mart. The curve of distribution of individuals in diametric classes followed a negative exponential pattern (inverted J-shape), with most individuals in the smallest diametric classes. These results imply that the forest presents species typical of initial stages of succession. Thus, conservation actions are needed to increase the local diversity. In addition, the studied forest is essential for academic and environmental education activities. We recommend further floristic studies in the area in order to assess the dynamics of the species in the forest community.

Nuevos registros de moscas de dos alas (Diptera: Brachycera) en colonias de avispas sociales (Hymenoptera: Vespidae) del bioma de la Mata Atlántica en el estado de Minas Gerais, Brasil

Nine new associations between dipterans and social wasp colonies are reported, providing information for understanding the ecological relationships between species in addition to new geographic distributions. The records took place between 2016 and 2018, in urban and secondary forest fragments in the cities of Cataguases, Goianá, Juiz de Fora, Muriaé, and Viçosa, all inserted in the Atlantic Forest biome in the state of Minas Gerais, Brazil. Understanding the ecological relationships between groups of insects provides subsidies for studies of ecology, biology, and behavior of the organisms involved in order to develop conservation strategies not only for the organisms but also for the areas where they occur.

Nuevos registros de moscas de dos alas (Diptera: Brachycera) en colonias de avispas sociales (Hymenoptera: Vespidae) del bioma de la Mata Atlántica en el estado de Minas Gerais, Brasil

Nine new associations between dipterans and social wasp colonies are reported, providing information for understanding the ecological relationships between species in addition to new geographic distributions. The records took place between 2016 and 2018, in urban and secondary forest fragments in the cities of Cataguases, Goianá, Juiz de Fora, Muriaé, and Viçosa, all inserted in the Atlantic Forest biome in the state of Minas Gerais, Brazil. Understanding the ecological relationships between groups of insects provides subsidies for studies of ecology, biology, and behavior of the organisms involved in order to develop conservation strategies not only for the organisms but also for the areas where they occur.

Effects of Vegetation Structure on Ant Diversity in Different Seasonal Periods in Impacted Fragments of Atlantic Forest

The destruction of forest habitats generates extremely fragmented areas and changes in vegetation structure. That changes the characteristics of microhabitats and the availability of resources and affects the diversity of animal species such as ants, which are a large group with an important ecological role. As ants forage on trees and shrubs, the vegetation structure can affect the presence of these organisms. Abiotic factors such as seasonality can also influence the diversity of the ant community. Based on that, this study aimed to investigate the distribution of the diversity of ant species that forage on plants in different seasonal periods. The study was carried out in eight secondary forest fragments of the Atlantic Forest. We used additive partitioning of diversity, partitioning of β diversity and canonical correspondence analysis to measure the effect of seasonality and vegetation structure on the distribution of ant species diversity. The rainy season positively influences the diversity of ants that forage on plants. Composition was affected by shrub leaf density in the rainy season and by tree circumference in the dry. Each fragment preserved a different pool of ant species, and the vegetation structure positively influenced ant diversity. These results highlight the importance of conserving the majority of forest fragments to better preserve the pool of ant species regionally.

Physical and chemical properties of Coarse Woody Debris submitted to the natural process of decomposition in a Secondary Atlantic Forest Fragment in Brazil

Coarse Woody Debris (CWDs) are constantly exposed to the natural decomposition process of wood, which can lead to a change in its physical–chemical properties. However, these changes have not yet been fully elucidated, requiring further studies to help to understand the effect of this process on CWDs degradation. Thus, the objectives of this study were: (i) verify if the decomposition affects the physical–chemical properties of the CWDs; (ii) verify if the structural chemical composition of the CWDs is altered as a function of decomposition, using immediate chemical and thermogravimetric analysis. Wood samples were collected from the CWDs to carry out these analyses, considering pieces with diameters ≥ 5 cm separated into 4 decay classes. The results indicated that the average apparent density decreased as a function of the increase of CWDs decomposition (0.62–0.37 g cm−3). The averages contents of Carbon and Nitrogen suffered less impact with the increase of CWDs decompositions, ranging from 49.66 to 48.80% and 0.52 to 0.58%, respectively. Immediate chemical and thermogravimetric analysis indicated a loss of holocelluloses and extractives and an increase in the concentration of lignin and ash throughout the decomposition process. The weight loss analyzed by thermogravimetric analysis was greater for less decomposed CWDs and with larger diameters. The use of these analyzes removes the subjectivity of CWDs decay classes, reducing the number of tests to determine CWDs physical–chemical properties and increasing the studies accuracy focused on the carbon cycle of these materials.

Earthworm communities in long-term no-tillage systems and secondary forest fragments in Paraná, Southern Brazil.

The area destined for agricultural production in Paraná state in Brazil is ~6 million hectares, of which 79% are under no-tillage systems (NTS) that can positively affect earthworm populations. Furthermore, earthworm abundance and richness can be valuable soil quality. This study assessed earthworm communities in long-term no-tillage sites (NTS) and nearby secondary Atlantic Forest (SF) fragments. Sampling was performed in June 2018 and May 2019 using the quantitative Tropical Soil Biology and Fertility handsorting method (ISO-TSBF), complemented by qualitative sampling in three municipalities: Faxinal, Mauá da Serra and Palmeira, in NTS and SF. Eleven earthworm species, belonging to five families (Benhamiidae, Glossoscolecidae, Megascolecidae, Ocnerodrilidae, and Rhinodrilidae) were found along with seven native species (Glossoscolex sp.22, Glossoscolex sp.23, Fimoscolex sp.21, Fimoscolex sp.24, Fimoscolex sp.42, Andiorrhinus duseni and Urobenus brasiliensis) and four exotic or cosmopolitan species (Dichogaster gracilis, Amynthas gracilis, Metaphire californica and Pontoscolex corethrurus). The cosmopolitan P. corethrurus dominated Faxinal and Mauá da Serra, while in Palmeira Fimoscolex and Glossoscolex were the most abundant. Six species belonging to Glossoscolex and Fimoscolex were new to science and must be described. Overall, 239 individuals were found. In 2018 126 individuals were found (76 in NTS and 50 in SF) and in 2019, only 112 individuals were found (45 in NTS and 67 in SF). The highest earthworm abundance was in Faxinal (123 individuals), with 76 individuals in NTS and 47 in SF. In Mauá da Serra the same pattern was observed (SF>NTS), while in Palmeira in overall, fewer individuals (38) were collected (24 in NTS and 14 in SF). The NTS at Faxinal and SF Mauá da Serra in 2019 had only/more exotic/cosmopolitan species, while at the other dates and sites >50% of the specimens sampled were native species. Overall, forests had more native species than exotics: in 2018, natives represented > 75% of all specimens, but in 2019 both Faxinal and Mauá da Serra had more exotic species (> 65%), while at Palmeira, they represented 50% of the individuals. Earthworm total biomass for forest sites was higher in Faxinal (3.2 g) and NTS in Mauá da Serra (1.7 g) in 2019. Overall, the total biomass was higher in SF sites than NTS. Using a classification available for earthworm populations in no-tillage systems, all three sites were considered to have poor quality in terms of abundance (ind m-2), while for species richness, they were considered to have moderate (Faxinal and Mauá da Serra) and good quality (Palmeira).

Temporal dynamics of ectomycorrhizal fungal communities in Shorea siamensis forest fragments

Investigating the dynamics of ectomycorrhizal fungal (EMF) communities in seasonally dry tropical forests is essential for sustainable management and for understanding the resilience of this forest type in future climate change scenarios. EMF communities in secondary forest fragments with Shorea siamensis as a single host tree species in central Thailand were sampled seasonally for 2.5 y. Ten EMF taxa were identified from ectomycorrhizal morphotypes, with/tomentella-thelephora and/russula-lactarius as the dominant taxa. Seasonal differences in EMF diversity were not detected; the dominant morphotypes were present in both seasons and their abundance varied. Most EMF taxa exhibited wide environmental ranges and only a few taxa were correlated with soil moisture. Seasonal dynamics of ectomycorrhizal colonization was likely influenced by climatic factors and the phenology of host species. Together, these results suggested that climatic variation may have a long-term and subtle influence on the composition of ectomycorrhizal communities. • Ectomycorrhizal fungi in secondary Shorea siamensis forest fragments in Thailand. • Fungal taxa were common species found in deciduous dipterocarp forests. • Lack of seasonal differences in fungal community composition. • Root number and ectomycorrhizal colonization were influenced by precipitation. • Broad environmental ranges of ectomycorrhizal fungi imply resilience.

Floristic composition and dispersal syndrome: How can environmental factors affect the Cracidae refuge in a secondary Atlantic Forest fragment?

The Atlantic Forest is a threatened biodiversity hotspot. Anthropogenic and environmental factors affect this biodiversity, including floristics and, consequently, the seed dispersal syndrome. The objective was to evaluate the influence of environmental factors on floristic composition, seed dispersal syndrome and potential for wild fauna refuge, especially birds of the Cracidae family, in a Private Reserve of Natural Heritage (RPPN) in the Atlantic Forest. The study was carried out in a forest fragment of 631 ha in the RPPN Fazenda Macedônia in Ipaba, Minas Gerais, Brazil. Twenty-three plots (10 × 50 m) were inventoried at three sampling levels with the plots being selectively distributed, considering the different geoenvironments. Environmental factors were divided into edaphic (soil chemical and physical) and landscape (altitude, slope, terrain exposure and edge distance) variables. Species composition and plot groupings by smallest dissimilarity were calculated. The dispersal syndrome and the type of zoochoric dispersal were determined for tree species. The species dispersed by birds had records of occurrence in the verified cracid diet. Two hundred and forty-nine species from 138 genera and 46 tree families were recorded. The dissimilarity between plots ranged from 0.4 to 1.0 forming four groups. Floristic composition was influenced by soil variables (soil pH, available potassium and magnesium, exchangeable aluminum, effective and potential CEC, remaining phosphorus, organic matter and silt) and landscape (altitude). The zoochoric dispersal syndrome was the most frequent, with ornithochory (68.09%) being the most important within this group. In the RRPN, 35 species of tree were recorded in the cracids diet. Tree species composition of varied with edaphic variables and with altitude. The wide distribution of species recorded in cracid diets reaffirms the fragment's potential for the establishment and conservation of these birds, highlighting the importance of creating and protecting private conservation areas, such as the RPPN Fazenda Macedônia.

Conspecific density plays a pivotal role in shaping sapling community in highly fragmented subtropical forests

AbstractTropical and subtropical regions shelter high levels of biodiversity. A combination of biological, environmental and anthropogenic factors influences tree community diversity and composition. Here, we use data from the IFFSC project to test the effect of conspecific and heterospecific density dependence, canopy cover and distance to edge on saplings populations of 229 woody species in 159 plots distributed across three forest types in Southern Brazil. All plots were measured twice with a standardized time interval of 5 years. We fitted one ordinary least square regression model to each species to test the strength of each predictor on the species' population growth rate, and one global mixed effect model including forest type, ecological group and the interaction between distance to edge and conspecific density to test their impact in the overall trend of the species. Our analysis provided circumstantial evidence that conspecific density dependence is shaping diversity of forest fragments. This mechanism was present for 75.5% of the species, while heterospecific density affected 10% of the species. Canopy cover affected the population dynamics of 9.2% of the species and distance to edge affected 7.4% of the species. Forest type had a significant effect in the global model, suggesting that population dynamics differ between different forest formations. Ecological group was not significant in the global model suggesting that the mechanism affects species similarly despite their ecological group. The interaction between distance to edge and conspecific density was significant in the global model, suggesting that this mechanism differs between interior and edge of fragments. This work represents one of the few large‐scale analyses of conspecific density dependence in fragmented secondary forests. Our results show that, once the forest is stablished, conspecific density dependence is crucial in sapling population dynamics, despite high levels of fragmentation.

Potential of slash-and-mulch system with legumes to conserve soil attributes and macrofauna diversity in Eastern Amazon

Slash-and-burn agriculture has been practiced for thousands of years in the tropics and is sustainable in conditions of low population density, and long fallow. However, the population increase leads to intensification, and consequently the reduction of fallow, productivity, and sustainability. Then, public and private institutions with farmers, are seeking alternatives to replace this farming system. The slash-and-mulch technique for smallholder farmers is widespread in Central America and has the potential to be transferred to other regions. Nonetheless, little information is available about its potential for the eastern Amazon. The soil macrofauna is associated with soil quality and agricultural sustainability as it plays a key role in the provision of ecosystem services. Higher taxa of this fauna are often used to evaluate soil management, given that they are influenced by land-use and produce a fast response. Therefore, this study evaluates the short-term effects of the slash-and-burn or the slash-and-mulch system, after different durations of fallow on the composition, density, and diversity of the soil macrofauna higher taxa and selected physical and chemical attributes. Results are compared to old-growth forest and secondary forest fragments. The slash-and-mulch fields had soil fertility attributes similar to slash-and-burn and macrofauna diversity and composition were similar to forests. In particular, functional groups like ecosystem engineers or predators augmented with slash-and-mulch and were efficient indicators of land-use change. Despite its scarcity and their very high fragmentation, old-growth forest small remnants do conserve a more diverse and abundant soil invertebrates community of saprophages and predators, therefore their conservation is of utmost importance. This is the first study to show the potential of the slash-and-mulch system in this region to enhance the resilience of the smallholders' landscapes. Nonetheless, soil quality needs to be monitored to confirm the effective restoration of soil functionality and agriculture productivity.

Multi-year, post-harvesting impact assessment in a neotropical secondary Atlantic Forest

Subject to overexploitation in the past centuries, the Atlantic Forest is subject to very rigorous protection rules. However, the law is a controversial issue since landowners are not compensated for the limited choice of land use possibilities. We believe that, alternatively to a general timber harvest ban, sustainable forest management of the Atlantic Forest has the potential to generate income for the landowners while sustaining important ecological functions of the forest. Such choice would require better understanding of the potential effects of timber harvesting on the forest ecosystem and on species composition and succession over time. In this context, we assessed the harvesting impact of a conventional harvesting method (CM) and compared it to an alternative harvesting method (AM) in three different stands (stands A, B and C) of a secondary forest fragment in southern Brazil. Results from three comprehensive forest inventories over a period of two years were used to assess the timber harvesting impact. Measurements of species composition (i.e., number of species, life form, ecological group), forest structure (i.e., density, basal area, DBH, volume) and saplings density formed the basis of the impact assessment. The inventories were carried out before, immediately after and two years after harvesting. Intensities of damage on remnant trees immediately after harvesting and two years after harvesting were also measured. Before harvesting, a total of 114 tree species (trees, tree fern and palm tree) belonging to 49 families were identified in the study site’s three research stands. Palm trees and secondary species, such as Euterpe edulis, represented the majority of recruited individuals (DBH ≥ 5 cm) two years after harvesting. However, new saplings (DBH ≤ 5 cm) after two years were mainly pioneer woody tree species, such as Cecropia glaziovii and Schizolobium parahyba. On average, AM reduced damage to saplings by 5%. Most of the damages caused by CM were moderate to severe, while AM caused light to moderate damages. Binary logistic regression indicated dependency of the mortality rates on the independent variables “stand, stem and leaning damages.” On the other hand, the recovery rates of damaged trees were dependent on crown, stem and leaning damages. Therefore, two years after harvesting a higher mortality rate of low-dimensional trees was observed in stands with high density of smaller trees and high density of improvement felling. Although crown damages were not related to mortality rates, high intensity of crown damages reduced recovery rates over time.

ESTIMATIVA DE VOLUME DE MADEIRA POR USO DE VARREDURA A LASER TERRESTRE: MÉTODO EM FLORESTAS SECUNDÁRIAS HIPERDIVERSAS

ABSTRACT High accuracy in timber volume estimation in tropical forests is required to support sustainable management. Terrestrial laser scanners (TLS) can provide high-quality estimates from tree structural variables. We compared stem variable estimations obtained by TLS and traditional methods at tree level and adjusted volume equations using data of a secondary seasonal semideciduous forest (Atlantic Forest). We also discuss the feasibility of TLS in hyperdiverse and secondary forest fragments. Traditional measurements (Method I) and TLS-based measurements (Method II) were performed on 29 trees belonging to 10 species. Volume equations based on the Schumacher and Hall (SH) and Spurr models were generated. DBH (diameter at breast height) was equal for both methods. Total height (TH) was overestimated by Method II, and commercial height (CH) showed a low correlation between the two methods. The adjusted volumetric equations were different for both methods, and those based on the SH volume model showed the best fit. Our results lead us to infer that in hyperdiverse secondary forests, tree structural variables should be obtained via TLS. However, attention should be given to the occlusion of target trees by the regenerating understory and to height estimates, which can be biased by the crown characteristics of the dominant species.

Description of the unknown female of Cosmosoma papalo (Laguerre, 2010) (Lepidoptera: Erebidae, Arctiinae) with a new state record from Mexico

ABSTRACT The female of Cosmosoma papalo (Laguerre) and its genitalia are described and illustrated here for the first time. A new record of this endemic moth provides a distributional extension of 101 km to the northwest of the type locality, in a secondary cloud forest fragment of mountainous central Veracruz, Mexico. Biogeographic comments on distributional patterns are made.

Topography as a determinant of bird distribution in secondary Atlantic Forest fragments

AbstractThe spatial distribution of Neotropical birds at local scales is often associated with plant successional stages and unique microhabitats such as bamboo stands and treefall gaps. Only 15% of the Atlantic Forest remains, yet this habitat is home to more than 200 endemic birds. Understanding the distribution of bird species within the Atlantic Forest can improve the test of ecological hypotheses related to habitat use and habitat selection. This study analyses the distribution of birds among different types of relief (lowlands, ravines, hillsides, and hilltops) in 41 forest fragments of different sizes (1 to 384.5 ha) within the Atlantic Forest, south east Brazil. The presence and absence data were analysed with dynamic occupancy models to determine the influence of area and topography in the distribution of bird species. Of the 169 species detected, we were able to estimate an occupancy probability of 67. Among them, relief type was an important variable for 26 species (39%). Most species showed a preference for lowlands and ravines, and some showed an association of combinations of these two reliefs with hillsides and hilltops. These preferences might be related to distribution of preferred food, nesting microhabitats, and thermoregulation. For the endemic and threatened Atlantic Forest mountain birds, the ecological association with areas of relief is a strong, and previously unsuspected, spatial distribution pattern. Our results suggest that the ecology and distribution of birds in tropical forests across hilly regions could be better understood if topography is considered. This pattern should be better investigated among other taxa in tropical forests.

Spatial and Temporal Distribution of Leafhoppers (Hemiptera: Cicadellidae) in a Corn Field.

Leafhoppers (Hemiptera: Cicadellidae) are phytophagous insects that transmit diseases and cause damage to this crop. Thus, the main goal of this study was to verify the spatiotemporal behavior of the leafhoppers Tapajosa ocellata (Osborn, 1926), Dechacona missionum (Berg, 1879), and Dalbulus maidis (DeLong, 1923) in a corn field in Igarapé-Açu, northeastern Pará, northern Brazil. An area of 1.0 ha was used for the development of the study. A mango agroecosystem, a pasture, and secondary forest fragment are adjacent to the experimental area. The sampling of leafhoppers occurred during the 2015 and 2016 harvests. For sampling, 10 random plants per plot were analyzed, totaling 1000 plants per sample. In order to verify the occurrence of leafhoppers, all aerial parts of the plants were analyzed visually. The spatiotemporal behavior of leafhoppers and influence of adjacent areas and phenological stages of corn were verified through geostatistics. From the composition of semivariograms, interpolation maps were constructed by kriging. The results showed that, in 2015, there was a higher incidence of D. maidis compared to the following year. In 2016, 352 individuals of T. ocellata and 66 of D. missionum were observed. Regarding the spatial distribution, it was found that the smallest area of influence of T. ocellata, D. missionum, and D. maidis was 0.09, 0.08, and 0.05 ha, respectively. The spatial distribution of leafhoppers showed an aggregate behavior concentrated close to adjacent areas with a predominance of grasses. Population fluctuation demonstrated that the highest incidence of leafhoppers occurs in the vegetative stages of corn.