Fragments Of Tropical Dry Forest Research Articles

Variations in the plasticity of functional traits indicate the differential impacts of abiotic and biotic factors on the structure and growth of trees in tropical dry forest fragments

Abiotic and biotic factors have considerable impact on the plasticity of plant functional traits, which influences forest structure and productivity; however, their inter-relationships have not been quantified for fragmented tropical dry forest (TDF) ecosystems. We asked the following questions: (1) what are the variations in the plasticity of functional traits due to soil moisture availability in TDF fragments? (2) what are the roles of soil nutrients and forest disturbances in influencing variations in the plasticity of functional traits in the TDF fragments? and (3) how do the variations in the plasticity of functional traits influence the structure and productivity of TDF fragments? Based on linear mixed-effects results, we observed significant variations among tree species for soil moisture content (SMC) under the canopy and selected functional traits across forest fragments. We categorized tree species across fragments by principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) analyses into three functional types, viz., low wood density high deciduous (LWHD), high wood density medium deciduous (HWMD), and high wood density low deciduous (HWLD). Assemblage of functional traits suggested that the LWHD functional type exhibits a drought-avoiding strategy, whereas HWMD and HWLD adopt a drought-tolerant strategy. Our study showed that the variations in functional trait plasticity and the structural attributes of trees in the three functional types exhibit contrasting affinity with SMC, soil nutrients, and disturbances, although the LWHD functional type was comparatively more influenced by soil resources and disturbances compared to HWMD and HWLD along the declining SMC and edge distance gradients. Plasticity in functional traits for the LWHD functional type exhibited greater variations in traits associated with the conservation of water and resources, whereas for HWMD and HWLD, the traits exhibiting greater plasticity were linked with higher productivity and water transport. The cumulative influence of SMC, disturbances, and functional trait variations was also visible in the relative abundance of functional types in large and small sized fragments. Our analysis further revealed the critical differences in the responses of functional trait plasticity of the coexisting tree species in TDF, which suggests that important deciduous endemic species with drought-avoiding strategies might be prone to strategic exclusion under expected rises in anthropogenic disturbances, habitat fragmentation, and resource limitations.

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.

What Do Butterflies Tell Us about an Intermediate Disturbance in a Dry Tropical Forest Context?

Montes de María is the best-preserved tropical dry forest fragment in the Colombian Caribbean, making it an ideal location for studying the impacts of human disturbance on local ecosystems. In this study, we analyzed the community structure of diurnal butterflies in both forested and disturbed areas using 16 circular plots to identify relationships between alpha and beta diversity, and the geographic distance between disturbed areas and native forests, using a range of metrics, including range–abundance and rarefaction curves, nonlinear models, and the Bray–Curtis dissimilarity index. The results revealed three distinct species assemblages associated with forests, intermediate disturbed areas (IDAs), and disturbed areas (DAs). Nonlinear models show that IDAs are more diverse than forests and DAs. However, forests have more beta diversity in plots than IDAs and DAs. Indicator species for each butterfly assemblage were also identified. Thus, although new butterfly species assemblages emerge from a new human landscape, it is clear that species that only occur within dry forest fragments are lost when forest fragments disappear. Overall, these findings have important implications for conservation efforts and understanding how human disturbance affects biodiversity in tropical ecosystems.

Spatial Turnover and Functional Redundancy in the Ants of Urban Fragments of Tropical Dry Forest

Spatial and temporal variation in the diversity of ants in four urban fragments of the tropical dry forest in the city of Santa Marta was evaluated. The fragments were sampled four times in the dry and rainy season, from October 2019 to January 2020, using pitfall traps, mini-Winkler bags, baits, and manual collection. Both alpha and beta taxonomic diversity and their components were quantified. The functional groups were established based on proposals for Neotropical ant species. A total of 7 subfamilies, 37 genera, and 84 species were collected. Richness varied spatially from 33 to 61 species, but between the two seasons it was 72 and 76 species. Sites N01 and N02 had greater diversity than N03 and N04. In all the fragments, soil ants were dominated by Ectatomma ruidum, but litter ants showed a structure with less dominant species. The dissimilarity between fragments was 60–80%, attributable mainly to turnover (50–70%) but not to nestedness (10%). Seventeen functional groups were identified. Taxonomic diversity of ants in urban fragments in Santa Marta showed marked spatial variation, without influence from the seasons. Despite taxonomic turnover, there was broad similarity in functional groups between the fragments, indicating ecological equivalence of species between the ant assemblages.

Molecular Detection of Rickettsia and Other Bacteria in Ticks and Birds in an Urban Fragment of Tropical Dry Forest in Magdalena, Colombia.

Birds are important hosts in the life cycle of some species of ticks. In Colombia, there are few eco-epidemiological studies of tick-borne diseases; the existing ones have been focused on areas where unusual outbreaks have occurred. This study describes the identification of ticks collected from birds and vegetation, and the detection of bacteria in those ticks and in blood samples from birds in an urban fragment of tropical dry forest in the department of Magdalena, Colombia. Bird sampling was carried out monthly in 2021, and 367 birds, distributed among 41 species, were captured. All collected ticks were identified as Amblyomma sp. or Amblyomma dissimile. The presence of rickettsiae in ticks collected from birds was evaluated by molecular analysis of the gltA, ompA and sca1 genes. 16S rRNA meta-taxonomy was used to evaluate rickettsiae in ticks collected from vegetation and in blood samples from birds. The presence of the species "Candidatus Rickettsia colombianensi" was detected in ticks from birds. Bacteria of the family Rickettsiacea was the most abundant in ticks collected from vegetation. Bacteria of the families Staphylococcaceae, Comamonadaceae and Pseudomonadaceae were prevalent in the samples of blood from birds. Rickettsia spp. was also detected in low abundance in some of the bird blood samples.

Litter dynamics in a seasonally dry forest fragment

Litter decomposition makes possible the nutrient cycling and is a link between vegetation and soil, vital for a healthy forest ecosystem. Although several studies on litter decomposition have been carried out in different regions of Brazil, there are few studies for transitional zones between Cerrado and Caatinga, particularly in the state of Piauí. Therefore, the objective of this work was to evaluate the litterfall production, litter composition and decomposition rate in a tropical dry forest fragment located in the southeast region of Piauí, Brazil. Monthly litterfall dynamics were evaluated for one year, by placing litter traps in the center of six forest inventory permanent sample plots, and the decomposition rate was determined by the litterbag technique. Litterfall production was estimated at 4,401.7 kg ha-1 year-1, similar to Caatinga environment values, with the leaves fraction contributing with the highest percentage (64%). On the other hand, litter decomposition rate was estimated at 0.003 g day-1, similar to rates found in Cerrado environments, highlighting the importance to better understand this ecozone litter dynamics. Wind speed had significative correlation with litterfall production. The number of species in the sample plot had highest correlation with the decomposition rate, and the diameter growth rate was the dendrometric variable most correlated to litterfall production.

Seed’s morpho-anatomy and post-seminal development of Bromeliaceae from tropical dry forest

Abstract Drastic changes in dry tropical forest result in the loss of biological components and reveal the importance of studies on the biology of species living in it. The present study aimed to describe seed morphoanatomy, germination and post-seminal development of Bromeliaceae species in fragments of tropical dry forest in Sucre, Colombia. Seven species representing Bromelia and Tillandsia genera were evaluated. The results provide characteristics related to the habitat of each species and contribute to distinguish the genera evaluated: fruit and seed measurements, seed shape, plumose appendage, testa characteristics, and the aleurone layer, embryo endosperm ratio, types of reserves, constriction zone in the embryo and type of post-seminal development. Characteristics of plumose appendages and the presence of vascular bundles in the embryo also contribute to distinguish Tillandsia species. In T. elongata and T. flexuosa, high number of seeds per fruit (> 100), morphoanatomical aspects, high germination (> 92%) and plant formation (> 77%) percentages, and higher germination rate values (> 4.5) give them the potential capacity for establishment in this environment. Our results provide information with taxonomic and ecological relevance for bromeliads in dry tropical forest.

Silvopastoral and conventional management of extensive livestock and the diversity of bats in fragments of tropical dry forest in C\xf3rdoba, Colombia

The establishment of extensive livestock systems in the Colombian Caribbean Region has historically generated a strong loss of the tropical dry forest (TDF) with negative effects on biodiversity. Currently, the implementation of silvopastoral systems (SPS) has been proposed with strategy to curb the loss of biodiversity caused by the conventional management system (CS). The objective was to evaluate the effect of SPS and CS of extensive livestock on the assemblage of bats associated with fragments of TDF. During a continuous year and a sampling effort of 30,240 h-net/night, the structure and composition of bat assemblage between SPS and CS were compared. 2788 bats belonging to six families, 23 genera, and 39 species were captured. The Phyllostomidae family presented the highest species richness (S = 30), with the greatest abundance in the Stenodermatinae subfamily (n = 1543). Bat assemblage in the SPS fragments was more equitable; and the relative abundance per species, per genera, and per foraging guilds was also significantly higher. The capture success showed significant variations between the climatic seasons (dry and rainy). The rate of species turnover was higher in the CS fragments. The species Artibeus planirostris, Artibeus lituratus, Carollia perspicillata, Carollia castanea, Phyllostomus discolor, Dermanura phaeotis, Uroderma convexum, Glossophaga soricina, C. brevicauda, and Sturnira lilium accounted for 92% of the captures. In conclusion, frugivorous bats were more abundant in the SPS, type of extensive livestock management that can generate greater temporal stability of bat assemblage. This research provides the first scientific evidence of the positive effect of silvopastoral management on the diversity of bats in tropical dry forest areas of the Colombian Caribbean region.

Small non-volant mammals from Bosque Protector Cerro Blanco, a fragment of tropical dry forest in western Ecuador

Basic diversity studies of small non-volant mammals are scarce in western Ecuador, evidencing a knowledge gap regarding the mammalian fauna in the region. These organisms play key roles in important ecological processes and may be affected by several anthropogenic factors. Herein we report the results of a rapid assessment of marsupials and rodents of Bosque Protector Cerro Blanco (Guayas province), a fragment of dry forest surrounded by urban development. Between October 2016 and March 2017, we trapped rodents and marsupials with Sherman and Tomahawk live traps; also, we conducted direct observations and searched for skeletal remains. We recorded nine species of small non-volant mammals, seven native and two invasive. The marsupial Marmosa simonsi was the most frequently captured species. We reported three previously unrecorded species for this reserve: Sigmodon peruanus, Aegialomys baroni, and Rhipidomys latimanus. We recommend continued monitoring of the mammalian fauna of Cerro Blanco using alternative techniques such as pitfall traps, canopy live traps, and analysis of owl pellets. These efforts will permit a better understanding of the marsupial and rodent assemblage in this important site for biodiversity conservation in coastal Ecuador, a region that unfortunately faces intense human pressure.

Geographic distance and environmental variation drive community structure of woody plants in Neotropical seasonally dry forest fragments in the Colombian Caribbean

ABSTRACT Background Montes de María is the best-preserved tropical dry forest fragment in the Colombian Caribbean, making it a good model to relate environmental and geographic factors to woody plant community structure. Aims We related alpha and beta diversity of woody plant communities to geographic distance and bioclimatic factors to understand the underlying factors of community structure. Methods We compared species composition among seven sites and calculated alpha (using effective numbers of species) and beta diversity using Whitaker and Bray–Curtis dissimilarity index. Canonical correspondence analysis (CCA) and a Mantel test were used to quantify how community structure was related to environmental and/or geographic distance. Results We found that Montes de María is as diverse as other dry forest fragments in Colombia. We detected three groups of communities which were shaped mainly by turnover associated with both precipitation and geographic distance. Conclusions The high beta diversity of the dry forest of Montes de María is related to a mixture of environmental variation and geographic distance.

Living fences decrease the edge effect on nest predation in a tropical dry forest landscape: evidence from an experiment using artificial nests

Agricultural expansion has contributed to the loss and fragmentation of natural habitats and, as a consequence, the edge effect in these habitats has increased, leading to nest predation rates higher at the edge of fragments than in the interior. Living fences in abandoned croplands, however, add a structural component to the landscape which can help to mitigate the effects of disturbance. We used artificial nests to assess whether a living fence at the edge of a fragment of tropical dry forest, immersed in an agricultural landscape, can assuage the edge effect by decreasing predation rates. We identified the predators that attacked nests at several distances from the living fence and related the frequency of predator attacks with plant height, leaf height diversity, and tree and herb coverage. Vegetation structure of the living fence was vertically more complex than that found inside the fragment. 52% of nests were predated and we did not find a significant relationship between predation rates and the proximity of nests to the living fence, suggesting a null edge effect on predation. Birds were the most frequent predators, followed by rodents and carnivorous mammals, with the composition of predators varying among transects. The composition of predators and vegetation structure of the living fence were the factors that explained the null edge effect on nests predation. Our results indicate that the presence of a living fence at the edge of a fragment in agroforestry systems could mitigate the edge effects on nest predation.

Diversity of longhorned beetles (Coleoptera: Cerambycidae) in the Caribbean region of Colombia: temporal variation between two fragments of tropical dry forest

Abstract: The tropical dry forest is under constant threat from many anthropic activities which are conducted indiscriminately, modifying the forest, and therefore, affecting species that are closely related to its phenology, such as longhorned beetles (Cerambycidae). The spatio-temporal variation of the cerambycid diversity in two fragments of tropical dry forest (Reserva Campesina la Montaña and La Flecha) in the Caribbean region of Colombia was analyzed. At each locality, four squared plots were delimited, and the beetles were collected with fruit traps, beating sheets and manual capture, and with light traps in the center. Five hundred eighty-seven specimens representing 128 species were collected, of which members of the tribe Ectenessini (Cerambycinae) were the most abundant. At the subfamily level, Cerambycinae was the most abundant (465 specimens) and diverse (73 species), followed by Lamiinae and Prioninae. The highest values of richness (110 species), abundance (428), biomass (21.18 g), and as well as the highest values of true diversity (1D= 73.44, 2D= 34.30) were found during the first precipitations. Regarding beta diversity, temporal variation was determined and mainly explained by a high percentage of turnover (> 70%). Lastly, the high diversity of Cerambycidae was associated with high values of relative humidity and canopy cover during the rainy season. This showed that the structure of the cerambycid community in the tropical dry forest of the Caribbean region of Colombia depends on these variables, which are closely related to precipitation.

Understanding the ecology of medium-sized carnivores (Mammalia: Carnivora) from a Tropical Dry Forest in Colombian Caribbean

Fauna in Tropical Dry Forest (TDF) is highly dependent on water availability due to a marked seasonality in precipitation. There are few studies addressing carnivore’s ecology and the role of seasonality of TDF in Neotropics. We used scent-station and camera trapping to assess seasonal changes in occurrence and habitat use probability with seasonality. We also described activity patterns and collected fresh scats to describe diet for small sized carnivore species in a TDF fragment in the Colombian Caribbean region. We present information regarding: Cerdocyon thous, Leopardus pardalis, and Procyon spp. The analysis showed a significantly higher occurrence probability during the dry season for the three species, and no differences in the detection probability between seasons. The diet of C. thous included 24 different food items; for L. pardalis it was composed of seven items, and finally, 25 food items were identified in the diet of Procyon spp. We found that the three species presented activity patterns corresponding with previous studies. Finally, our results reflect that these species are probably making more/larger habitat use during the dry season than in the wet season, because the area has permanent water ponds by which limited resources (such as water and food) are available almost constantly in this natural reserve.

Differences in body mass among the frugivorous bats Artibeus lituratus and Carollia perspicillata (Chiroptera: Phyllostomidae) from an urban and a peri-urban area of Cúcuta, Colombia

We report differences in body mass of two species of fruit bats, Artibeus lituratus and Carollia perspicillata, from two fragments of tropical dry forest (TDF) located in urban and peri-urban areas of the city of Cúcuta, Colombia. From January to September 2018 bat sampling was carried out using mist nets to captured and weigh individuals in the field. The analysis was based only on adults who were not in a reproductive state. We found that both males and females of each species had a higher body mass in the peri-urban area than in the urban area. This highlights the importance of testing subsequent hypotheses to explain the body mass variations reported in this note in response to effects related to diet, diseases, and changes in land use, among others.

Low adaptive and neutral genetic diversity in the endangered Antioquia wren (Thryophilus sernai)

Determining the amount and distribution of genetic variation represents a fundamental step for the inference of evolutionary processes acting on populations of endangered species. For these species, adaptive evolutionary potential is highly reduced by the loss of genetic variation due to drift. Here, we examined genetic diversity at the mitochondrial control region (CR), 17 microsatellites, and six Toll-like receptor (TLR) genes, known to play a key role on the innate immune response of vertebrates in the Antioquia wren (AW) Thryophilus sernai, an endangered passerine bird inhabiting the remnant fragments of tropical dry forest in the northernmost part of the Cauca river canyon, Colombia. We found very low variation for the three types of markers. The CR showed scarce variability, while only six of the 17 microsatellites analyzed and two of the six TLRs sequenced were polymorphic. Population structure analyses suggest the occurrence of one single population in the area. Selection tests could not detect signatures of positive selection for the variable sites in the species, and assessment of amino acid changes found within the lineage do not suggest any functional effects that could be associated to selection in either polymorphic TLR loci. Comparisons with species showing widespread and restricted distribution supports a low TLR variability typical of small populations. These results suggest current low evolutionary potential for the species, as its reduced genetic diversity is expected to increase extinction risk by limiting the ability to cope with environmental changes. Our study supports current evidence suggesting drift as the main driver shaping TLR variation.

<p><strong>A new species of Capparidastrum (Capparaceae Juss.) from the Cauca inter Andean valley of Colombia</strong></p>

We describe and illustrate a new species of Capparidastrum subgen. Pulviniglans (Capparaceae). Capparidastrum dugandii occurs in tropical dry forest fragments of the Colombian inter-Andean valley of the Dagua River, near the municipality of Santa Fe de Antioquia. Capparidastrum dugandii is distinguished from other species of subgen. Pulviniglans molecularly and by the lowest number of stamens (18–20). In addition, the species is endemic to the Cauca biogeographic province.

Nutrient stock and nutritional efficiency of woody species in dry tropical forest as reforestation indicators

ABSTRACT Efficient forest species can be indicated for reforesting environments, which present nutritional restriction. The objective of this study was to determine the nutrient stock in leaf biomass of the species of greatest importance value (IV) in a tropical dry forest fragment, as well as to evaluate the nutritional efficiency of these species as reforestation indicators. A phytosociological study of the woody species was carried out defining the ten species with the greatest IV. Three individuals of each species were selected and sampled, with 25 leaves being collected from the middle part of the crown of each individual. The N, P, K, Ca and Mg contents were determined in these leaves and the leaf biomass was estimated by an allometric equation, calculating the stock of these nutrients and the nutritional efficiency of the species. The Schinopsis brasiliensis and Mimosa tenuiflora species can be recommended in environments with restricted P availability, and Spondias tuberosa can additionally be indicated to populate areas with low levels of K and Mg in the soil. Differences in the nutritional efficiency of the species can be attributed to the differences in the absorption and translocation capacity, as well as the utilization of these nutrients.

Phytogeography and Floristic Affinities of Woody Plants in “Los Montes de María”, a Tropical Dry Forest Fragment in the Colombian Caribbean

The phytogeographic and floristic connections of the “Montes de Maria” (MM: north of Colombia) were analyzed through Geographic Information Systems, at worldwide, Neotropical and in Colombia scales in order to determine its geographical origin and floristic affinities. We estimated that genera are mostly of the Neotropical (74%) and Nearctic (26%) origin. At the Neotropical level, MM is located at the Pacific dominion and shares species with the Mesoamerican dominion. In addition, shares species with the Chaquena, Antilles subregions, and the South American and Mexican transition zones. At the regional level, the MM is located between Guajira and Magdalena provinces, although is floristically more similar to Guajira province. MM shape a floristic unit together with other fragments of dry forest in the Colombian Caribbean, which is highly related to dry forests of the inter-Andean valleys. In addition, the floristic origin of MM is associated to dry flora of Mesoamerica, nonetheless it was also influenced by the Amazonian and the Sabana province.

A new species of the armored spider genus Caraimatta Lehtinen, 1981 from Colombia (Araneae: Synspermiata: Tetrablemmidae).

A new species of the armored spider genus Caraimatta Lehtinen, 1981 from Colombian Tropical dry forest fragments is described and illustrated: Caraimatta brescoviti sp. nov. (based on male and female) from Bolivar and Sucre departments, representing the first record of the genus from Colombia. Additionally, photographs of Monoblemma muchmorei Shear, 1978 (other tetrablemmid species previously recorded from the country) are given. A map with the known distribution and an identification key for males and females of the Caraimatta species are also included.

Use of forest strata by bats according to wing morphology and habitat complexity in a fragment of tropical dry forest (Colombia)

Use of forest strata by bats according to wing morphology and habitat complexity in a fragment of tropical dry forest (Colombia)