Biotropica最新文献

Reforestation projects in the tropics often consist of plantations, typically monocultures of non-native timber species. It has been questioned whether such plantations are suitable as wildlife habitat, but empirical evidence is scarce, especially on plantations embedded on highly disturbed landscapes. Here, we compare species richness and occupancy of ground-dwelling mammals between five types of plantations within a single area in Central Panama, the narrowest tract of the Mesoamerican Biological Corridor. We deployed camera traps at stratified random points and followed a hierarchical modeling approach to compare community composition and occupancy between plantation types. We found a total of 16 ground-dwelling mammals in the area, most of which were small-bodied and short-lived, and the majority of species' occupancy probabilities were below 0.5 at any given plantation. Teak (Tectona grandis) plantations, which covered the largest area in the study, had the lowest estimated richness and occupancy, with occupancy probabilities exceeding 0.5 for just three species. Conversely, plantations of the native Pachira quinata and the non-native Gmelina arborea, covering an area four and nineteen times smaller than Teak, respectively, had higher richness and occupancy. Occupancy values were intermediate in the Acacia and mixed plantation types. Our findings suggest that plantations embedded in lowland tropical landscapes have limited conservation value for large-bodied mammals, and are ecologically constrained habitats for small- and medium-sized mammals.

While the reassembly of fruit-frugivore interactions remains at the forefront of tropical forest restoration, seed dispersal networks emerge as a potential approach to enhance restoration success. This review explores the integration of seed dispersal networks in tropical forest restoration, with the aims of (1) synthesizing important findings in the literature, (2) detailing potential biases in utilizing network theory, and (3) addressing current knowledge gaps and future directions for the field. We first highlight the importance of combining phytocentric and zoocentric approaches when sampling for seed dispersal interactions, as different methodologies have varying effects on network measures, and combining approaches can foster a more comprehensive understanding of dispersal interactions. Furthermore, when integrating seed dispersal networks into restoration goals, we suggest a highly connected and species-rich network is desirable for earlier stages of forest succession where community turnover and transient interactions are pivotal. Nested patterns may emerge throughout varying stages of forest succession, and identifying generalist species that make up nested patterns may be useful for restoration practitioners in both early and later stages of forest regeneration. Modularity should be highest at later stages of succession to maintain community structure and stability, and connector species may play important roles in facilitating seed dispersal across temporal scales. Finally, we emphasize the importance of site-specific long-term datasets, chronosequences, and studies at large spatial scales to continue to understand network reassembly as a function of tropical forest succession and to develop effective strategies that enhance the recovery of tropical forest ecosystems.

The role of archeological zones in biological conservation has been highlighted because of their restrictions over land-use change, size, and maintenance of upstanding vegetation. The Yucatan Peninsula in Mexico has over 2000 archeological zones amidst biological, ecological, and culturally diverse landscapes. However, due to population centers and tourism growth, the peninsula is experiencing high deforestation and habitat fragmentation rates. To explore the role of archeological zones in biological conservation, we focused on bat species because of their high mobility, use of human structures as refugia, and the ecosystem services they provide. Using mist nets and roost surveys, we compared the bat diversity in four highly visited archeological zones during the dry and wet seasons. In a total effort of 34,560 m² mist net hours, we found 23 species from six families and seven guilds, representing 53% of all bat species known from the Yucatan state, including two endangered species for Mexico: Mimon cozumelae and Micronycteris schmidtorum. We found between 12 and 19 species in each archeological zone, and the communities were similar between the four sites and between seasons. The Phyllostomidae family was dominant across all sites, accounting for 92% of all the captures. We also recorded 12 species across 52 diurnal and nocturnal roosts, suggesting that Mayan archeological structures could offer several advantages to bats despite the high visitation of tourists. Our results emphasize the need to conduct research beyond natural protected areas to complement conservation policies and incentivize the inclusion of archeological zones in Yucatan's bat conservation plans.

Abstract in Spanish is available with online material.

Tropical forests are vertically complex and offer unique niche opportunities in the form of resources, climate, and habitat gradients from the forest floor to the canopy. Rainforest amphibians have diversified within this vertical space, resulting in partitioned niches and corresponding morphological, behavioral, and reproductive traits. However, a lack of data regarding the vertical niche space used by amphibian species has prevented a nuanced analysis of the form-function relationship between traits and vertical height. We performed 74 ground-to-canopy surveys for amphibians in the tropical rainforest of Gabon and described the vertical stratification patterns of the assemblage in terms of richness, abundance, and species-specific vertical niches. We determined that the community shift in richness and abundance between the ground and understory was pronounced, while the community change from understory to canopy was gradual. We analyzed the relationships between amphibian traits with vertical height using linear mixed effects models, finding strong support (>60% variance explained) that frogs with bigger toes in relation to their length access greater height in the canopy. This relationship provides support for the form-function hypothesis: that morphology changes predictably to meet the functional demands of species along niche gradients. Furthermore, we documented differences in the vertical heights of species according to their reproductive modes, highlighting the potential impact of reproductive mode diversity on the vertical stratification patterns of amphibian assemblages.

During a biodiversity monitoring of woody and herbaceous plants in 2023, we observed the formation of new individuals through cloning in Velloziaceae species. Based on recorded evidence and scientific literature, we discussed the importance of cloning in maintaining the high dominance of these species in seasonal open ecosystems. In addition, we hope to shed light on the discussion of the importance of asexual reproduction through cloning and resprouting strategies in plants widely widespread in savanna ecosystems.

Abstract in Portuguese is available with online material.

The Amazon rainforest faces escalating human disturbances such as logging, mining, agriculture, and urbanization, leading to the conversion of primary forest into matrix habitat. This transformation's impact on mesocarnivores, specifically ocelots (Leopardus pardalis), is still largely unknown. In 2021, we deployed camera traps across a 174 km² study area in Las Piedras, Madre de Dios, Peru, containing mixed land use and protected forests. Utilizing kernel density functions, we compared temporal activity patterns and employed spatially explicit capture-recapture (SECR) models to assess density, encounter probability, and movement by habitat and trail type, as well as sex. Of the 293 captures, we identified 39 ocelots (21 females, 18 males), estimating an average density of 31.46 (SE 5.15) individuals per 100 km² with no significant difference between protected and mixed-use areas. Baseline detection and movement varied by sex, with male and female home ranges estimated at 17.14 and 4.10 km², respectively. Ocelot temporal activity patterns differed between the protected area and the mixed-use area, with increased nocturnality in areas of higher human impact. Our SECR results highlight that matrix habitats can support ocelot populations, emphasizing the need for further research on ocelot demographics in human-modified Amazon rainforest areas facing varying degrees of anthropogenic disturbance.

Abstract in Spanish is available with online material.

Insects in islands may undergo morphological variations related to the geographic isolation faced by their populations. This isolation on insular biota can vary according to the history and characteristics of the islands, as well as the dispersal ability of each species. We investigated the existence of morphological variations in the populations of the Canthon rutilans cyanescens dung beetle from the southern Brazil islands and the nearby mainland. Dung beetles were sampled from December/2020 to April/2021 from five Islands in the Santa Catarina Archipelago and on the mainland through samplings with baited live traps. With geometric morphometry analyses and individuals from each population we compared the body size using an Analysis of Variance and body shape using a Discriminant Analysis with cross-validation test, followed by a Canonical Variable Analysis to visualize the populations in morphometric space. We found a significant difference in the body length: the population of Ratones Grande Island has smaller individuals than the populations of the mainland, Dona Francisca Island, and Peri on Santa Catarina Island. We also observed that the body shape of the population of Campeche Island differs from the populations of Arvoredo Island and Dona Francisca Island, with a slightly oval body, a larger dorsal region, and a retracted abdomen. These results are consistent with the hypothesis that the populations found on the islands may have remained there since their formation after the Last Glacial Maximum. The isolation and the absence of connectivity between the populations would explain why some islands have populations with distinct morphology.

Abstract in Portuguese is available with online material.

Caatinga's conservation and biodiversity are threatened due to the intensification of anthropic activities and climate change. The mammals have different responses to seasonal and anthropic changes, however particularly in Caatinga, these effects are still poorly understood. We assessed the influence of anthropic (distance from urban areas and wind farms), environmental (distance from water), and seasonal (Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST)) variables on the number of records and richness of medium and large-sized mammals in Brazilian Caatinga. We used camera traps in 2016–2017 and 2018–2019, estimated the variation (cv) of NDVI and LST, and generated Euclidean distance maps to anthropic and environmental variables at 250, 500, and 1000 m spatial scales. We performed Generalized Linear Models, used the Akaike information criterion, and calculated model averaging to assess the strength and direction of effect and the uncertainties of the winner models, respectively. The distance from wind farms and maximum LST had a noticeable effect on the number of records and total richness. The distance from wind farms had a negative effect on the records of Dicotyles tajacu and a positive effect on the records of Leopardus pardalis and richness. The maximum LST had a negative effect on the records of L. pardalis and a positive effect on the records of Puma concolor and Cerdocyon thous. Our results emphasize that an unsustainable expansion of wind farms is likely to compromise mammal diversity. We found an opposite pattern for some species regarding LST. However, it is important to highlight that the conservation of vegetation areas on the top of mountains and springs, and the installation of artificial water sources are important strategies to mitigate the impacts of high temperatures on mammals' biodiversity in Caatinga.

Abstract in Portuguese is available with online material.

Caves provide relatively stable and advantageous roosting sites for bats compared to more open roosts, like tree foliage. This environment may have the drawback of facilitating interactions with their ectoparasites due to the confined spaces. Understanding the structure of interactions between bats, acting as hosts, and bat flies, serving as parasites in cave ecosystems, is a crucial first step in deciphering the roles of each species (pullers and pushers) within the networks that form in subterranean ecosystems. Here, we describe and evaluate the network structures of bat-fly interactions in two distinct cave systems: cold caves (n = 10), also known as bat caves, and hot caves (n = 6). Based on the records of 700 bats from 16 species and 1.412 bat flies from 30 species we uncovered highly distinct topologies comparing hot and cold bat caves that differed also in terms of interactions, specializations, and modularity. We found relatively lower specialization and modularity in hot caves compared to the cold caves, which may be associated to the bat composition and the cave microclimate. Bat flies were highly species-specific in relation to their bat hosts and dependent on the bats in both hot and cold caves systems. The differences in network structure and at the species level between the bat (cold) and hot caves systems suggest that bat-fly interactions are shaped by the host species' composition and by the cave system type. Those differences stem from each bat species' adaptation to extreme cave microclimates and their species-specific roosting behaviors.

Abstract in Portuguese is available with online material.