Tropical Forest Remnants Research Articles

New amphibian records for the Serranía de San Jacinto, Bolívar Department, Colombia

The San Jacinto Highlands are a mountainous formation that is part of the Montes de María in theColombian Caribbean Region. It harbors remnants of Tropical Dry Forest, which is rapidly disappearing due to developmentfor agriculture and livestock. This loss impacts amphibian diversity by fragmenting habitat, creating homogeneouslandscapes, and reducing environmental complexity. Despite its ecological importance, information on theherpetofauna in this region is limited due to access and security issues. We herein present five new amphibian records(Rhinella alata, Hyalinobatrachium tatayoi, Colostethus inguinalis, Boana rosenbergi, and Dendropsophus ebraccatus) forthe Bolívar Department, which extend the distributions of these species.

Using proxy data and vegetation modelling to predict past, current and future distributional shifts of Butea monosperma, a marker of land degradation in India

Extensive deviations in spatio-temporal social and environmental dynamics currently alter the health of ecosystems and the services they provide. Detecting the causes that contribute to the distribution of a natural forest species capable of restoring the lost ecosystem function and productivity will aid in determining better food security, livelihoods and provision of ecosystem goods and services. We modelled the spatial range of Butea monosperma (B. monosperma) under past, that is, Last Glacial Maximum (LGM), Middle Holocene (MH), current and future (2070) climatic scenarios with Maximum Entropy (MaxEnt) trained on present-day occurrences. We identified areas of suitable habitats for which the estimation of habitat stability is predicted in all the models at different times. To validate the inferred suitable habitat, we tested the model by the current occurrence and fossil pollen data of B. monosperma. Our distribution models agree with the fossil pollen records for the MH (4,500–7,000 yr BP) and predict the prevalence of B. monosperma covering 84.22% of the Indian subcontinent with maximum habitat stability in western and southwestern India (10.95%). The widespread potential distribution of the plant species during the LGM supports the presence of the last remnants of tropical dry deciduous forest in the region. However, a decline in habitat suitability (62.84%) is predicted under current and future climatic scenarios with maximum stability (0.90%–3.09%) along the Western Ghats, Nilgiri hills, Gir range in the western India and north-eastern region covering the Assam Valley and foothills of Tripura and Mizo hills. Temperature seasonality (33.6%) measured in terms of variable contribution in MaxEnt model significantly affects the distribution shift of B. monosperma, along with annual precipitation (22.8%) and annual mean temperature (16.2%). Model results provide evidence of habitat reduction and identify the stability hotspots for B. monosperma for its conservation and establishment of land management policies mainly for the dry tropics.

Long-term change in the tree community of a tropical forest remnant surrounded by human-modified landscapes

Long-term change in the tree community of a tropical forest remnant surrounded by human-modified landscapes

Molecular Discrimination for Two Anadenanthera Species of Seasonally Dry Tropical Forest Remnants in Brazil

Anadenanthera colubrina (Acol) and Anadenanthera peregrina (Aper) (Fabaceae) are two species popularly known as “angicos” that occur in seasonally dry tropical forest (SDTR) remnants in Brazil. Since many of the morphological characteristics of Anadenanthera species are superimposed and species-specific characteristics are difficult to observe, their identification is complex. Therefore, in this research, a set of ISSR (Inter-Simple Sequence Repeat Polymorphic DNA) molecular markers was standardized, aiming to characterize A. colubrina and A. peregrina species and study the genetic diversity of three populations of each species located within a fragmented landscape in São Paulo State, southeastern Brazil. Seven ISSR markers (UBC 2, 820, 851, 858, 864, 866, and 886) that show polymorphism for both species were used. The Bayesian cluster, PCoA and dendrogram analysis show that the total sample divides into two groups corresponding to each species. Also, a genetic divergence (Gst = 0.143) and a high number of migrants per generation (Nm = 3.0) were detected between them. The Acol populations showed significantly higher values for mean genetic diversity (h = 0.30) than Aper (h = 0.25) (p < 0.05). The ISSR marker UBC2250bp showed species-specific electrophoretic fingerprints for both species. The molecular tools generated herein support the conservation of Anadenanthera sp. and the restoration of vegetation where the species naturally occurs.

Bioclimatic predictors of forest structure, composition and phenology in the Paraguayan Dry Chaco

Abstract One of the largest remnants of tropical dry forest is the South American Gran Chaco. A quarter of this biome is in Paraguay, but there have been few studies in the Paraguayan Chaco. The Gran Chaco flora is diverse in structure, function, composition and phenology. Fundamental ecological questions remain in this biome, such as what bioclimatic factors shape the Chaco’s composition, structure and phenology. In this study, we integrated forest inventories from permanent plots with monthly high-resolution NDVI from PlanetScope and historical climate data from WorldClim to identify bioclimatic predictors of forest structure, composition and phenology. We found that bioclimatic variables related to precipitation were correlated with stem density and Pielou evenness index, while temperature-related variables correlated with basal area. The best predictor of forest phenology (NDVI variation) was precipitation lagged by 1 month followed by temperature lagged by 2 months. In the period with most water stress, the phenological response correlates with diversity, height and basal area, showing links with dominance and tree size. Our results indicate that even if the ecology and function of Dry Chaco Forest is characterised by water limitation, temperature has a moderating effect by limiting growth and influencing leaf flush and deciduousness.

Chiropteran diversity and diet of fruit bats in a tropical dry forest of northern South America

Remnants of Tropical Dry Forest persist in urban and peri-urban areas and are essential for maintaining biodiversity and ecosystem services. However, the challenges facing the conservation of these respective forests have intensified with the encroachment of the urban frontier, mining activities, deforestation, and cattle ranching. In this context, our study aims to estimate the diversity of the order Chiroptera and characterize the diet of the family Phyllostomidae. This approach allows us to gain insights into the ecological dynamics and assess the status of Tropical Dry Forest fragments located within the urban and peri-urban areas of Cúcuta, Colombia. Field sampling was conducted from January to September 2018, with a total sampling effort of 2,160 hours/meter/net. Bats were sexed, morphometrically characterized, and had their feces collected for diet analysis before being tagged and released. We identified three families, nine genera, and 11 species. A total of 276 individuals were captured. Seven species were observed in the urban area and ten in the peri-urban zone; Artibeus lituratus and Carollia perspicillata were the most abundant species in both locations. The diet included seeds from the families Moraceae, Anacardiaceae, and Rosaceae. Our findings reveal that in areas with dense vegetation, such as peri-urban zones, frugivorous bats prefer to consume fruits of domesticated species, including economically significant fruits like guava and tomato. This dietary shift could alter seed dispersal patterns and the dynamics of the Tropical Dry Forest, highlighting the ecological importance of these flying mammals in ecosystem regeneration.

Conserving the threatened woody vegetation on dune slopes: Monitoring the decline and designing adaptive strategies for restoration

The southern tip of the Thal desert in Pakistan harbors the remnants of the original tropical thorn forest, amounting to two percent, which covered the province of Punjab a hundred years ago. In the past three decades, there has been a progressive decline in woody species cover on dunes, which is directly related to the increase in population in the surrounding area. Stabilized and destabilized dunes were subjectively selected followed by quantification of cover and diversity of woody species on the top and lower slopes. Dunes closely resembling the overall cover were grouped to suggest corresponding restoration measures. The results suggest that trends of decrease in cover and diversity of woody species were evident in the upper slopes of some stabilized dunes having less than 50% cover. The destabilized dunes with less than 20% cover are highly vulnerable to erosion. A general trend observed among dunes was that with a decrease in the cover of upper slopes, there is a decrease in the cover on lower slopes. The number of destabilized dunes is increasing without effective restoration measures against the prevailing trends of disturbances. Ranking dunes on the basis of cover could help in proposing simple restoration measures as a first step towards developing an understanding of designing adaptive strategies to restore the woody cover.

Spatio-temporal variation of seed rain between urban and rural fragments of humid tropical forests

Introduction: The type of land use surrounding the remnants of tropical forest may generate changes in the characteristics of plant populations and communities. Consequently, there may be a significant reduction in processes of pollination and diasporas dispersion. Therefore, causing changes in some parameters of seed rain. Objective: To characterize and compare seed density, species richness, floristic composition, habit, dispersal syndrome, and successional category of seed rain between urban and rural fragments of Atlantic Forest, in the 2015 and 2016 weather seasons. Methods: The study areas were defined after mapping and quantification of urban and rural occupations around the remnants, based on satellite images. In each fragment, were installed 36 collectors of 0.25 m2. The material was collected monthly during two consecutive years. Results: Seed rain richness was higher in the urban fragment during the rainy season in the two years, whereas it was similar between the fragments in the dry season. The seed density in the rural fragment was higher than in the urban during the rainy season; did not vary in urban between years or between seasons; and it was higher in the rural fragment in the rainy season of one year. There was a difference in the floristic composition of the seed rain between the fragments along time. The variations in the functional attributes of habit, dispersal syndrome, and successional category, were explained by the variables fragment, season, and year. Conclusions: Differences in the characteristics of the seed rain between the fragments might reflect the spatial and temporal heterogeneity, due to the diverse uses of the soil and external pressures (anthropogenic actions) present in the surroundings of the forest fragments and temporal variation in precipitation.

Little noticed, but very important: The role of breeding sites formed by bamboos in maintaining the diversity of mosquitoes (Diptera: Culicidae) in the Atlantic Forest biome.

This study investigated the composition of mosquito species in different kinds of breeding sites in a tropical forest remnant of the Atlantic Forest and identified species of public health concern therein. Collections of immature forms of mosquitoes were carried out monthly at the Poço das Antas Biological Reserve in southeastern Brazil, between June 2014 and June 2015. Samples were collected from four types of breeding sites: bamboos, bromeliads, puddles, and a lake. A total of 1,182 specimens of mosquitoes belonging to 28 species and 13 genera were collected. Three species, Ad. squamipennis, An. neglectus, and Wy. arthrostigma represented 64.8% of the captured specimens. Only three species were found in more than one type of breeding site: Ps. ferox, An. triannulatus, and Tx. trichopygus. Two species of public health concern were found breeding in bamboo (Ae. aegypti and Ae. albopictus) and one in the lake (An. darlingi). Bamboo had the highest species richness, Shannon diversity, abundance of individuals and number of dominant species of all breeding sites. Similar Simpson diversity was obtained for bamboo and bromeliads, with higher values than those obtained for puddles and the lake. The significance of the four breeding sites, especially bamboos, is discussed in the context of controlling populations of sylvatic species of mosquitoes in Atlantic Forest areas.

Use of artificial nest boxes by two species of small, arboreal mammals in ecuadorian tropical dry forest

ABSTRACT The nest structure of two species of small mammals, Marmosa simonsi and Rhipidomys latimanus were recorded for the first time. Nests were found inside artificial nest boxes in a tropical dry forest remnant ecosystem in Western Ecuador. We described the nests and categorized them as rearing nest, permanent resting nest and transient refuge, depending on their intended use. Artificial nest boxes provide an optimal place for pup rearing and resting for these small mammals. These nest sites can be useful for ecological studies of behavior and habits of elusive, poorly-known mammalian species.

Seasonality and bait type driving the diversity of dung beetle (Scarabaeidae: Scarabaeinae) communities in urban remnants of the Atlantic Forest

Describing dung beetle communities in tropical forest remnants located in disturbed/urbanized and conserved areas can provide information about the functioning of these ecosystems and support conservation plans. This study aimed to verify the effect of seasons and bait type on dung beetle communities in remnants of the Atlantic Forest in order to describe their composition and diversity parameters. The study was carried out during both the rainy and dry seasons in periurban and urban remnants. Eighteen pitfall traps baited with feces, carrion, and injured millipedes were established in each site. A total of 3501 individuals and 23 species were recorded. Urban remnant presented higher abundance of individuals in the dry season. On the other hand, in periurban remnant the higher abundance was verified in the rainy season. The diversity was higher in the rainy season in both sites. In urban remnant, Coprophanaeus ensifer was found to be generalist regarding its choice of bait (feces and carrion). The use of injured millipedes as bait allowed the record of the predatory species Deltochilum alpercata. Among the types of bait used, the injured millipedes proved to be very effective, capturing a greater diversity of dung beetles during the rainy season in both remnants, and allowed the collection of specialized, necrophages, and generalists species. Therefore, we propose the use of mixed-bait sampling designs in inventories and surveys to increase the chances of sampling species with different traits or dietary preferences, which are often rare in collections.

Analysis of trends and changes in the successional trajectories of tropical forest using the Landsat NDVI time series

The vegetative growth of forest canopies changes their spectral response, which can be detected by multispectral sensors and enhanced by utilizing the normalized difference vegetation index (NDVI). The structural variability of canopies in heterogeneous forests can also be related to successional stages. Thereby, a spatiotemporal methodology is presented to associate the 3D photogrammetric information, derived from aerial images, with the NDVI time series extracted from the Landsat imagery, using spatial units connected to ecological succession. The technique is based on time series clustering within superpixels (extracted from the local variance of tree heights) and on trend analysis of the canopy using the breaks for additive season and trend (BFAST) algorithm. The study was conducted in a tropical native forest remnant (Inland Atlantic Forest) in the western region of São Paulo State, Brazil. We investigated the relationship between the variability of the forest vertical structure and the NDVI temporal trajectory associated with vegetation vigor in the period from 1984 to 2010. The experiments produced a regularized time series of overlaid superpixels. The cluster statistical analysis was successful in separating the NDVI trajectory into ten classes associated to successional stages, in which the evolution of the vegetation vigor could be observed and compared within degraded, transitional, and preserved areas. Such areas overlapping with the ten trajectory classes allowed us to quantify that 59.9% of the clusters were related to preserved areas, 30.1% to transitional areas, and 10.0% to degraded areas. Additionally, the BFAST algorithm allowed the identification of trend measures and the occurrence of disturbance events within these trajectory classes based on the vegetation response. Therefore, the classification of NDVI trajectory clusters helps to understand how the areas in a heterogeneous forest with different succession stages develop spectrally. Furthermore, monitoring secondary forests is essential for the conservation of biodiversity, ecosystem functioning, and carbon stock, among other values.

Variation in dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) assemblages in a tropical forest remnant from a Mexican National Park

The Cañón del Sumidero National Park (PNCS) is a priority area for conservation, but there are few studies on its fauna, which evidences the need for further basic studies to produce adequate knowledge on its biodiversity. This study aimed to determine dung beetle assemblages temporal distribution, trophic preference, and daily activity patterns. We conducted samplings using baited pitfall traps in a PNCS tropical sub deciduous forest remnant, during the dry and rainy seasons between 2014 and 2015. We captured a total of 863 individuals of 20 species, 12 genera, and five tribes of Scarabaeinae. Estimators suggest that we obtained high faunistic representation (> 80%), but species richness is low compared to other regional studies. The community was characterized by a high number of rare species and few dominant species. We captured the greatest richness and abundance during rainy months, however, species composition between seasons did not differ significantly. Trophic preference was mainly generalist and we considered only four species as specialists to tapir dung. We observed a clear segregation between activity hours. Nevertheless, we determined only nine species as specialists (six nocturnal and three diurnal) and two others had generalist habits. The low diversity we found could be influenced by the constant pressure of the urban area and non-native species within the park, which alter the dung beetle assemblages. However, performing samplings for longer periods and using a wider range of resources would help us obtain more robust results and better understand species distribution patterns.

The Road to Operationalization of Effective Tropical Forest Monitoring Systems

The urgency to preserve tropical forest remnants has encouraged the development of remote sensing tools and techniques to monitor diverse forest attributes for management and conservation. State-of-the-art methodologies for mapping and tracking these attributes usually achieve accuracies greater than 0.8 for forest cover monitoring; r-square values of ~0.5–0.7 for plant diversity, vegetation structure, and plant functional trait mapping, and overall accuracies of ~0.8 for categorical maps of forest attributes. Nonetheless, existing operational tropical forest monitoring systems only track single attributes at national to global scales. For the design and implementation of effective and integrated tropical forest monitoring systems, we recommend the integration of multiple data sources and techniques for monitoring structural, functional, and compositional attributes. We also recommend its decentralized implementation for adjusting methods to local climatic and ecological characteristics and for proper end-user engagement. The operationalization of the system should be based on all open-source computing platforms, leveraging international support in research and development and ensuring direct and constant user engagement. We recommend continuing the efforts to address these multiple challenges for effective monitoring.

Diversity of Convolvulaceae from Meruoca Massif, Ceará, Brazil

Abstract We present the taxonomic treatment of Convolvulaceae for the Meruoca Massif, located in the Northwest region of the Ceará state, where there are remnants of Tropical Pluvial Sub-deciduous Forest (Dry Forest) and Tropical Pluvial-Nebular Rainforest (Wet Forest). The present study was based on the morphological analysis of specimens collected in the field and from the collections EAC, HUEFS, HUVA, PEUFR, and SPF. We recorded 24 species distributed in four genera: Ipomoea (18 species), Jacquemontia (three species), Distimake (two species), and Camonea (one species). We report the first records of I. cearensis for Atlantic Forest and I. aristolochiifolia to the state of Ceará. The taxonomic treatment includes identification key, morphological descriptions, geographic distribution, taxonomic and ecological comments, the period of flowering and fruiting, and photos and illustrations of the diagnostic characters.

The role of seed size in the emergence and survival of seedlings in contrasting environments: the case of Ceiba aesculifolia

In the tropical low deciduous forest, seed size has been recognized as a functional trait that can contribute to the development of restoration strategies due to its influence on the processes of germination, survival and growth of seedlings. The objective of this study was to evaluate the effect of seed size on the seedling emergence and establishment of seedlings of Ceiba aesculifolia in pastures and remnants of tropical low deciduous forest in central Veracruz, Mexico. Three seed sizes were evaluated: small (120–218 mg), medium (219–316 mg) and large (317–414 mg). Seedling emergence rate was estimated, height, foliar production, stem thickness and insect herbivory were measured monthly in the seedlings. Seedling emergence differed significantly among seed sizes. The large seeds emerged at 40% in the pastures and 24% in the forest remnants, while the medium seeds presented 20 and 27% in these sites, respectively. The small seeds emerged similarly in the pasture (33%) and forest remnant (28%) sites. In the pastures, regardless of seed size, the seedlings presented significantly higher growth rates and foliar production, as well as an increase in the percentage of herbivory. At the end of the study, there was no difference in seedling survival between seed sizes or sites. The results suggest that the seed size only influences the seedling emergence, while the growth and responses to herbivory depend on their functional traits to face the environmental conditions of the sites. Finally, the ecological and management implications for future restoration programs are discussed.

Un caso de leucismo parcial en la ardilla de cola roja Notosciurus granatensis (Rodentia: Sciuridae) en el Sur-oeste de Ecuador

La presente nota da a conocer un caso de leucismo parcial en Notosciurus granatensis. El individuo fue avistado en la provincia de El Oro, cantón Pasaje, sector La Loma. El 7 de octubre de 2017, a las 12h44, se observó, entre un remanente de bosque tropical y un cultivo de cacao, presentaba hipopigmentación en la parte terminal de la cola. Si bien se desconoce la razón de su causa, se discuten posibles razones.

Seasonal influence on foraging activity of scorpion species (Arachnida: Scorpiones) in a seasonal tropical dry forest remnant in Brazil

ABSTRACT In Brazil, the Caatinga ecoregion is the only biome that lies completely within the country, covering approximately 11% of the national territory. This biome exhibits a strong climatic seasonality that may affect the activity of its fauna. We aimed to assess the effects of seasonality on scorpion foraging activity in an area of hypoxerophytic Caatinga, located in the municipality of Caetés, Pernambuco. Scorpions were collected through active nocturnal searching using ultraviolet flashlights during the rainy (May, June, and July) and dry (September, October, and November) seasons in 2017. A total of 96 specimens were collected, belonging to the Buthidae and Bothriuridae families, comprising seven species, Ananteris sp., Tityus pusillus, T. stigmurus, T. neglectus, Jaguajir rochae, Bothriurus asper, and B. rochai. No differences in foraging activity (rainy season, n = 47; dry season, n = 49) were found between rainy and dry seasons. These findings indicate that the studied area has a high scorpion richness, emphasizing the importance of conserving the area, as these animals are sensitive to habitat changes. In addition, the lack of variation between seasons found in this work may reflect the ecotonal nature of hypoxerophytic Caatinga.

Bats use live fences to move between tropical dry forest remnants

AbstractLinear features can benefit wildlife by assisting animal movement. We captured bats along barbed‐wire and live‐tree fences connecting tropical dry forest patches in Nicaragua. Bat species richness and captures were higher along live fences but we noted differences in sex ratios, richness, and species composition compared to surrounding natural forests.Abstract in Spanish is available with online only

Is forest remnants able to support bird community? Case in tropical lowland forest of West Java, Indonesia

Lowland tropical forests have undergone intensive fragmentation, resulting in the creating of many forest remnants. The aim of the research was to reveal how much tropical lowland forest remnant in West Java is able to support bird communities. The research was conducted during rainy and dry season in Dramaga and Haurbentes Experiment Forest (each covered 60 ha), by employing a standard point count method, for 5 days in each land use, using a 1.2 km transects of 5 points each (300 m distance) in April to October 2016. Shannon-Wiener (H’) and Jaccard’s similarity indices (SIJ) were calculated. The variation of species composition for both seasons was also compared. Bird richness was 30 species for Dramaga (H’ 2.72) and 39 species for Haurbentes (H’ 2.91), both seasons combined. SIJ was 0.39 (both seasons combined). Season had a significant impact on bird diversity and composition, where rainy season supported more birds in Haurbentes, but the opposite in Dramaga. Forest remnants were able to support the bird community, mostly small-sized insectivores, frugivores, granivores, and nectarivores. Small remnants were not able to support raptors (e.g., kite), medium to large-sized frugivores (hornbills, pigeon), medium-sized woodpeckers, as well as species preferred thick bushes and shrubs (e.g. babbler, starlings, crows, magpies).