Biotropica最新文献

We quantified seed removal and artificial fruit-animal interaction rates in forests and cashew orchards, in Guinea-Bissau, to understand whether the effects of land-use change extend into ecosystem functions. We found higher removal rates of pumpkin seeds in the forests, where rodents were more often involved in the seed removal events.

Fire management remains controversial worldwide, in spite of longstanding Indigenous burning practices that have shown benefits to biodiversity. In the Neotropics, limited information is available on wildlife response to fire, particularly for medium and large mammals. We conducted 1 year of transect surveys to detect signs and live sightings of mammals in the Rupununi, Guyana, within a habitat matrix of savanna, wetland, and forest, where Indigenous fire management is practiced. Species richness showed a non-linear relationship with time since fire. The number of live observations decreased with time since fire. Individual species responded differently, and this may be explained by habitat preference and post-fire resource availability. Savanna species—giant anteater (Myrmecophaga tridactyla), nine-banded armadillo (Dasypus novemcinctus), and crab-eating fox (Cerdocyon thous)—favored fire, while forest-associated species—agouti (Dasyprocta leporina) and tapir (Tapirus terrestris)—avoided fire prone areas, although some species showed no such response. Our data suggest that mammals in the Rupununi show an ecological response to traditional fire management practices, but that fires affecting forested areas or forest connectivity could negatively impact wildlife. We recommend the promotion of traditional knowledge of fire and fire management among Indigenous Peoples, and the integration of this expertise to inform fire management policies. Combining traditional and scientific knowledge may help people and wildlife adapt to fire regimes that are increasingly driven by climate change and anthropogenic activities within fire prone savanna and forest landscapes.

Gut passage is an important but understudied component of animal-mediated seed dispersal that can impact germination and survival. Melastomataceae plants are abundant and ecologically important throughout the tropics, but studies have obtained contrasting results regarding effects of avian gut passage on melastome germination. We conducted a paired germination experiment to test how gut passage by four species of manakins—key avian dispersers of melastomes—affects germination of the pioneer melastome shrub Miconia rubescens. Manakin gut passage accelerated M. rubescens germination, with gut-passed seeds germinating an average of 5.1 days earlier than controls, and percent germination of gut-passed seeds was significantly higher at 20 and 40 days post-planting. Interestingly, manakin species varied in their gut passage effects, with L. velutina having stronger overall germination effects than M. manacus. Within species, greater body mass was correlated with higher percent germination and shorter times to first germination. Within M. manacus, seeds passed by females had significantly shorter times to first germination than seeds passed by males. Because control seeds were manually depulped in the experiment, the observed gut passage effects are likely attributable to minor scarification of the seed coat during gut transit. Our results suggest manakin gut passage can have biologically meaningful impacts on melastome germination, and the magnitude of these effects can vary based on manakin species, mass, and sex. This study refines our understanding of the “quality” component of seed disperser effectiveness in an iconic dispersal mutualism, with implications for plant community composition and recovery of deforested neotropical ecosystems.

Abstract in Spanish is available with online material.

Studying plant–herbivore interactions within tropical rain forests is fundamental to understanding their ecology and evolution. An important aspect of plant–herbivore dynamics is the role of temporal and taxonomic variables in determining associations between herbivores and their host. Using the diverse and chemically rich plant family Annonaceae (Magnoliales), we conducted a year-long study in Ecuador's Yasuní National Park in lowland Amazonia. We focused on nine understory tree species across a broad phylogenetic range within Annonaceae. For these species, we investigated patterns of herbivory, identified herbivores through DNA barcoding, and documented unique ant–butterfly associations. In general, leaf damage ranged from 0.09% to 25%, with significant temporal fluctuations for three species. Notably, Anaxagorea brevipes and Unonopsis veneficiorum faced higher herbivore pressure when compared to the other studied species. We document a discreet but diverse herbivore community, with 40 larvae from 12 Lepidoptera families collected throughout the year. Our findings identify, for the first time across a phylogenetically diverse sampling of Annonaceae, the specialization of herbivores on our focal species. Overall, our data provide valuable information on herbivory patterns at the local scale for this important rain forest plant family. Furthermore, these findings contribute to our understanding of the ecological processes that influence plant species diversity in tropical rain forests.

Abstract in Spanish is available with online material.

Present-day Amazonia has an impoverished fauna of large folivorous mammals by comparison with African rainforests, but recent fossil discoveries suggest that late-Quaternary anthropogenic extinctions could account for most size and trophic faunal mismatches. The extent to which modern Amazonian ecology may be an artifact of prehistoric human intervention merits periodic re-evaluation as paleontological evidence of the Pleistocene megafauna continues to emerge.

We observed male euglossines collecting scent at 21 different non-floral sources in Central and South America, strengthening the view that these sources play a central role in euglossine perfume biology. A Protium tree provided over 50% of the perfumes for Eufriesea corusca and was repeatedly revisited. The co-occurrence of females collecting resin suggests an evolutionary link to male perfume-making.

Abstract in Spanish is available with online material.

Seedlings frequently suffer the highest mortality rate, as they have different requirements for growth and survival from their mature life cycle stage. However, the links between functional traits and photosynthetic traits of tree seedlings, especially from dry evergreen forests, remain largely unexplored. Here, we measured eleven functional traits and six photosynthetic traits of thirty species of tree seedlings from the seasonally dry evergreen forest in Southeast Asia. We explored the relationship between traits and photosynthesis, compared them with their canopy layers when mature, and classified growth strategies. The results showed that photosynthetic measurements were highly correlated with seedling growth traits. The measured functional and photosynthetic traits did not correspond with the canopy layers of the mature trees. Through k-mean clustering analyses of the tree seedling trait data, two main groups of growth strategies emerged: (1) the “fast-growing” group, which mainly consists of shade-intolerant or -avoidance species; and (2) the “slow-growing” group, which consists of shade-tolerant species. This finding can be applied by future practitioners to select tree seedlings accurately based on their juvenile physiology, which is fundamental to the success of species selection for forest restoration in the face of global climate change.

Large carnivores play a crucial role in trophic cascades, affecting the population dynamics of both co-predators and prey within an ecosystem. Understanding the significance of these carnivores in trophic interactions is essential for developing effective conservation and management strategies. We examined the effects of occupancy dynamics and patterns of species interactions and coexistence within the carnivore guild in the Panna Tiger Reserve in India. We collected camera trap data (two seasons, 2019) in a presence–absence framework and applied multispecies occupancy models to assess the occupancy, co-occurrence, and interactions among species. We also examined activity overlap to understand the temporal segregation in the carnivore guild. The mean marginal occupancy was highest for leopards in winter (Ψ_winter 0.92 ± 0.02, Ψ_summer 0.63 ± 0.05) and hyenas in summer (Ψ_summer 0.93 ± 0.03, Ψ_winter 0.78 ± 0.03) and was lowest for tigers in both seasons (Ψ_winter 0.62 ± 0.05, Ψ_summer 0.15 ± 0.05). Co-occurrence probability among carnivores was higher in winter than in summer, and conditional occupancy was consistently higher when other species were present. Different environmental factors influenced marginal occupancy and co-occurrence patterns across seasons. Strong temporal overlaps were recorded between tiger–leopard (0.87–0.91) and tiger–hyena (0.78–0.79). We detected a significant spatial segregation between tigers and leopards, as they prefer different habitat types in different seasons, along with high temporal overlap. Resource availability strongly governs the association of carnivores with their habitat selection. Hyenas demonstrated higher dependency on tigers than on leopards for resources. These findings indicate that coexistence with apex-predator species is feasible through strategic adaptation to fulfill resource requisition.

Large old trees (LOTs) are invaluable natural treasures and cultural legacies, holding ecological, historical, social, and economic significance. However, climate change and human impacts threaten their existence. Understanding their species composition, age structure, biomass, and distribution patterns in relation to environmental factors is essential for effective conservation. In Hainan Island, South China, we analyzed 1081 LOTs from 74 species across 35 families, using a combination of field surveys and government data. The dominant families were Moraceae, Sapindaceae, and Fagaceae, with key species including Ficus altissima, Litchi chinensis, and Tamarindus indica. The age distribution followed a reverse J-shape, indicating a prevalence of trees aged 300–399 years. In contrast, diameter at breast height (DBH) and height distributions were unimodal, favoring medium to large-sized trees. Spatial analysis revealed uneven distribution patterns: the western zone exhibited the highest species diversity, the central zone moderate diversity, and the eastern zone low diversity, reflecting uneven urban and agricultural impacts. Most LOTs were concentrated at elevations of 0–50 m. Factors such as GDP, urbanization, and forest cover positively correlated with LOT abundance and diversity, with forest cover and average annual temperature particularly favoring these trees. The findings emphasize the intricate relationship between environmental factors and LOT distribution. They advocate for tailored conservation strategies that address the complex interplay of ecological, socioeconomic, and cultural influences on their preservation.

Abstract in Chinese is available with online material.