Frugivory by Small Vertebrates Within a Deforested, Dry Tropical Region of Central America

Small vertebrates were inventoried within three habitat types in a degraded dry forest region of Panama. Animals were classified as frugivorous if they were observed foraging on fruit or if fecal samples contained mostly or exclusively seeds. Overall, we found that eight bat species and 21 bird species consumed fruit. The greatest numbers of birds were observed within live fences and bird species richness was greatest within riparian forests. Bat assemblages were not significantly different between habitats. The implication is that ecosystem services such as seed dispersal may still be functional in this landscape.     

Palm heart harvesting in the Brazilian Atlantic forest: changes in industry structure and the illegal trade

1. Until the late 1960s, Euterpe edulis was the most important edible palm species in the Brazilian markets. Since then, overharvesting of natural stands and the limited scope of plantations have caused the industry to shift to the multistemmed E. oleracea from the Amazon river estuary.
2. As a result of the relocation of the industry, the structure of the palm harvesting industry has changed and illegal trade has continued to exploit the remaining natural stands of E. edulis .
3. It is suggested that, to avoid the total harvesting of E. edulis and to achieve sustainable management of the palm heart, it will be necessary to diversify the local economy, create incentives for small land owners to improve their management practices, while keeping their competitiveness against the illegal trade, create the incentive of new sources of palm hearts and create a 'green stamping' for management palms.
4. Transformation of the illegal structure of the palm heart industry is probably the only solution to avoid the total depletion of the wild stands of E. edulis .     

Mammalian Densities in a Neotropical Wetland Subject to Extreme Climatic Events

Effective management and conservation of an ecosystem requires information on species assemblages as well as reliable estimates of population sizes to plan, implement and evaluate management strategies. The Brazilian Pantanal is one of the world's largest freshwater wetlands and considered a priority landscape for wildlife conservation. It is subject to pluri-annual extreme dry and wet periods, which cause extreme flood and drought events, which strongly affect wildlife. Using the line-transect method, this study examined the distribution of densities and metabolic biomass of medium- to large-sized nonvolant mammals in forest, cerrado and floodplain landscapes, in an area with low anthropogenic influence, in the central area of the Brazilian Pantanal during a prolonged drought. Comparisons with a previous survey conducted during years of average rainfall in part of the study area suggest that population fluctuations of certain species are closely associated with water due to the drought. Results from this study showed that mammal assemblages varied between landscapes. Forested landscapes have the highest densities of mammals and are the most important in terms of relative energy consumption. In addition, at the time of the study, frugivores were found to have higher energy consumption than browser/grazers across the three landscapes; most fruits are produced in forested areas stressing their importance. By converting forested landscapes into grasslands, the intensification of ranching practices seriously threatens biodiversity and ecological processes in the region.     

Determining nitrogen requirements of Aceros and Buceros hornbills

Over 2 months, seven feeding trials were conducted at St. Catherines Island, GA, to quantify protein intake and utilization in captive mature nonreproducing Aceros (n=3 spp.) and Buceros (n=2 spp.) Hornbills were fed homogeneous isocaloric diets. A mixture of Bird of Paradise pellets, grapes, and raisins was offered to the birds as grape‐sized balls, supplemented with diced cantaloupe melon to maintain hydration. To vary the protein level (range 10.8–22.6%) within the diets, different amounts of a powdered soy protein supplement were added to the mixture. Test diets were fed for 3 consecutive days. Birds were weighed to test for differences among diets. All excreta and diet samples were collected for nitrogen (N) analysis. Feeding trials were separated by a 4‐day period, in which the bird's regular diet was fed. Data were analyzed for N balance, N equilibrium (regression of N intake vs. N excretion) and body mass. Regression analysis of N balances of the nine birds showed that the N equilibriums ranged from 0.081 to 0.595 g N/kg^0.75/d with an average of 0.387±0.298. No differences in N balances were found between Aceros and Buceros hornbills. The methodology of this study suggested a dietary crude protein (CP) requirement of 7.3±3.0% dry matter (DM) in a diet containing 4.0 kcal. However, this value was determined by extrapolation and has not been experimentally determined to be adequate. In this study, the hornbills maintained body mass on a diet containing 10.8% CP (with energy at 4.0 kcal/g DM). Zoo Biol 27:282–293, 2008. © 2008 Wiley‐Liss, Inc.     

Long-term trends in fruit production in a tropical forest at Ngogo,Kibale National Park,Uganda

Fruit production in tropical forests varies considerably in space and time, with important implications for frugivorous consumers. Characterizing temporal variation in forest productivity is thus critical for understanding adaptations of tropical forest frugivores, yet long-term phenology data from the tropics, in particular from African forests, are still scarce. Similarly, as the abiotic factors driving phenology in the tropics are predicted to change with a warming climate, studies documenting the relationship between climatic variables and fruit production are increasingly important. Here, we present data from 19 years of monitoring the phenology of 20 tree species at Ngogo in Kibale National Park, Uganda. Our aims were to characterize short- and long-term trends in productivity and to understand the abiotic factors driving temporal variability in fruit production. Short-term (month-to-month) variability in fruiting was relatively low at Ngogo, and overall fruit production increased significantly through the first half of the study. Among the abiotic variables, we expected to influence phenology patterns (including rainfall, solar irradiance, and average temperature), only average temperature was a significant predictor of monthly fruit production. We discuss these findings as they relate to the resource base of the frugivorous vertebrate community inhabiting Ngogo.     

Cascading effects of climate extremes on vertebrate fauna through changes to low‐latitude tree flowering and fruiting phenology

Forest vertebrate fauna provide critical services, such as pollination and seed dispersal, which underpin functional and resilient ecosystems. In turn, many of these fauna are dependent on the flowering phenology of the plant species of such ecosystems. The impact of changes in climate, including climate extremes, on the interaction between these fauna and flora has not been identified or elucidated, yet influences on flowering phenology are already evident. These changes are well documented in the mid to high latitudes. However, there is emerging evidence that the flowering phenology, nectar/pollen production, and fruit production of long‐lived trees in tropical and subtropical forests are also being impacted by changes in the frequency and severity of climate extremes. Here, we examine the implications of these changes for vertebrate fauna dependent on these resources. We review the literature to establish evidence for links between climate extremes and flowering phenology, elucidating the nature of relationships between different vertebrate taxa and flowering regimes. We combine this information with climate change projections to postulate about the likely impacts on nectar, pollen and fruit resource availability and the consequences for dependent vertebrate fauna. The most recent climate projections show that the frequency and intensity of climate extremes will increase during the 21st century. These changes are likely to significantly alter mass flowering and fruiting events in the tropics and subtropics, which are frequently cued by climate extremes, such as intensive rainfall events or rapid temperature shifts. We find that in these systems the abundance and duration of resource availability for vertebrate fauna is likely to fluctuate, and the time intervals between episodes of high resource availability to increase. The combined impact of these changes has the potential to result in cascading effects on ecosystems through changes in pollinator and seed dispersal ecology, and demands a focused research effort.     

Nutritional Dimorphism in New Guinea Dioecious Figs

The life history of figs (Ficus, Moraceae) involves pollination by specialized insects and seed dispersal by vertebrate frugivores. This three-way interaction raises the possibility of conflict between pollinators and seed dispersers over fig resources. The conflict might be mediated in dioecious figs by the segregation of inflorescences with specialized male and female sexual functions, termed gall figs and seed figs, on separate trees. In dioecious figs, pollinators are intimately associated with gall figs, whereas vertebrate frugivores prefer seed figs and disperse the seeds they contain. Optimal foraging theory predicts that frugivore preference for ripe seed figs is associated with superior nutritional quality when compared to gall figs. We tested this prediction comparing nutrient and mineral properties of ripe figs in 12 functionally dioecious and two monoecious species from New Guinea. Analyses of variance indicated that gall figs contain more fiber and minerals, whereas seed figs contain significantly more carbohydrates and fat. Fruit bats, the primary dispersers of dioecious figs in New Guinea, prefer carbohydrate-rich diets, and from this perspective, seed figs offer a greater nutritional reward than gall figs. More nondigestible fiber in gall figs than seed figs would appear to discourage frugivory. Parallel differences between ripe gall figs and seed figs occur in each independent dioecious lineage whereas nutritional content in monoecious figs is more similar to seed figs. This suggests that sexual dimorphism in nutritional quality might be adaptive and associated with the maintenance of functional dioecy in figs.     

A Test of the Utility of Exotic Tree Plantations for Understory Birds and Food Resources in the Colombian Andes1

The spatial distribution and abundance of animals are in part determined by the distribution and abundance of their resource base. In the Central Andes of Colombia, monospecific tree plantations have been used to recover vegetative cover in watershed protection programs, but these plantations differ from natural forests in structure, composition, and resources available to wildlife. To evaluate these plantations as habitat for wildlife, we compared the diversity and abundance of understory birds, flowers, and fruits between juxtaposed 40‐yr‐old patches of exotic Chinese ash (Fraxinus chinensis) plantations and naturally regenerated forest of the same age. We observed more fruiting species in the regenerated forest, but there were no differences in total flower and fruit availability between habitat types. We also observed differences between habitats in the size of some understory shrubs, but these differences did not lead to differences between habitats in the diversity and abundance of birds. Capture rates of nectarivores correlated with resource abundance at sampling plot scale, but no such correlation was found for frugivores. Understory frugivorous birds are apparently functioning at a larger spatial scale than the patchiness created by the two habitats. Nectarivorous birds are responding to small‐scale patchiness in resource availability, but not to the different habitats. These results indicate that at small scales, the ash plantation understory provides adequate habitat for birds.     

RAPD variation and population genetic structure in Prunus mahaleb (Rosaceae), an animal-dispersed tree

We examined the patterns of random amplified polymorphic DNA (RAPD) variation among seven Prunus mahaleb (Rosaceae) populations extending over approximately 100 km2 to examine local differentiation in relation to spatial isolation due to both geographical distance and differences in elevation. No less than 51. 4% of the RAPD loci were polymorphic, but very few were fixed and among-population variation accounted for 16.46% of variation in RAPD patterns. Mean gene diversity was 0.1441, with mean Nei's genetic diversity for individual populations ranging between 0.089 and 0.149. Mean GST value across loci was 0.1935 (range, 0.0162-0.4685), giving an average estimate for Nm of 1.191. These results suggest extensive gene flow among populations, but higher GST and lower Nm values relative to other outcrossing, woody species with endozoochorous dispersal, also suggest a process of isolation by distance. The combined effect of both geographical and elevation distances and nonoverlapping flowering and fruiting phenophases on the GST matrix was partially significant, revealing only marginal isolation of the P. mahaleb populations. The matrix correlation between estimated Nm values among populations and the geographical + elevation distance matrices (r = -0.4623, P = 0.07), suggests a marginal trend for more isolated populations to exchange less immigrants. Long-distance seed dispersal by efficient medium-sized frugivorous birds and mammals is most likely associated to the high levels of within-population genetic diversity. However, vicariance factors and demographic bottlenecks (high postdispersal seed and seedling mortality) explain comparatively high levels of local differentiation.