bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental Effects on Components of Pollen Performance in Faramea occidentalis (L.) A. Rich. (Rubiaceae)1
Authors: Travers Steve E.
Published: March 2006

Studies focusing on gametophytic competition have focused on differences in pollen performance (e.g., pollen germination rate and pollen tube growth rate) among donors in order to examine genetic sources of variation in siring success among them. Donors that produce the fastest growing pollen tubes are expected to fertilize more ovules relative to donors with slow growing pollen tubes under conditions of gametophytic competition. However, the performance of pollen in the field is known to be influenced by environmental conditions in addition to the genotype of donor plants. This field study of Faramea occidentalis was conducted to: (1) determine the effect of environmental conditions during pollination on pollen performance; (2) measure differences among pollen donors in pollen performance; (3) determine if the pollen of different donors responds differently to a variety of environmental conditions surrounding pollinated flowers; and (4) measure differences among pollen recipients in pollen performance. Single‐donor crosses were made between four pollen donors and four pollen recipients under a variety of environmental conditions. Pollen performance was then quantified as the growth rate of the fastest pollen tube, the mean pollen tube growth rate, and by a pollen germination index. Pollination environment (the environment surrounding a pollinated flower) and recipient significantly affected all three measures of pollen performance. Pollen donors did not differ overall in pollen performance. However, there was significant among‐donor variation in two of the five pollination environment conditions. Future studies of variation in relative siring success may benefit by considering pollination environment in addition to donor and recipient identity.
Tropical Monodominance: A Preliminary Test of the Ectomycorrhizal Hypothesis1
Authors: Torti Sylvia D. , Coley Phyllis D.
Published: March 2006

This study reports results from the first explicit test of the ectomycorrhizal hypothesis for tropical monodominance in the Ituri Forest of the Democratic Republic of Congo (formerly Zaire), where the canopy tree Gilbertiodendron dewevrei forms large, monospecific stands. To test the hypothesis that ectomycorrhizae are important to the success of dominant species, we surveyed the mycorrhizal status of dominant species, as well as other common, but not dominant, species in the forest. The survey reveals that two dominant species, Gilbertiodendron dewevrei and Julbernardia seretii, form ectomycorrhizae and vesicular‐arbuscular mycorrhizae, while Cynometra alexandri, another dominant, forms only vesicular‐arbuscular mycorrhizae. These results, along with those of other species in this and other forests, are discussed within the context of the ectomycorrhizal hypothesis for tropical mondominance. This study demonstrates that the relationship between EM and tropical monodominance is more complex than has been previously recognized.
Nitrogen Fixation in Soils and Canals of Rehabilitated Raised‐Fields of the Bolivian Altiplano1
Authors: Biesboer David D. , Binford Michael W. , Kolata Alan
Published: March 2006

Raised‐field agricultural systems were exploited extensively by pre‐Columbian Andean civilizations and now are used less extensively by contemporary Bolivian and Peruvian farmers as a method for farming the perennially wet soils of the intermontane pampas of the Andean high altiplano. The raised‐field agricultural systems are linear or semi‐linear raised planting platforms interspersed with shallow, parallel canals filled with water. The elevated planting platforms raise the critical rooting zone of crops such as potatoes, quinoa, or barley above perennially saturated soils. A hypothesized advantage of the raised‐field system is that agricultural production can be increased by exploiting the ability of bacteria and Azolla fililculoides to fix nitrogen in the canals adjacent to the planting platforms.

To test this hypothesis, nitrogen fixation was estimated in situ in the water column of canals, in the soils of planting platforms, in the soils of a dry hillside field, and in the sediments and water column of marshes and totora beds. Nitrogen fixation was significantly greater in the canals of the raised‐field systems and in marshes compared to planting platforms and the hillside field. These data support the theory that pre‐Hispanic agricultural prosperity of the Andes, as well as other regions of Central and South America, was partially supported by extensive development of raised‐field agriculture and probable exploitation of nitrogen fixation.
Effects of Elevated CO2 and Defoliation on Compensatory Growth and Photosynthesis of Seedlings in a Tropical Tree, Copaifera aromatica1
Authors: Lovelock Catherine E. , Posada Juan , Winter Klaus
Published: March 2006

After defoliation by herbivores, some plants exhibit enhanced rates of photosynthesis and growth that enable them to compensate for lost tissue, thus maintaining their fitness relative to competing, undefoliated plants. Our aim was to determine whether compensatory photosynthesis and growth would be altered by increasing concentrations of atmospheric CO2. Defoliation of developing leaflets on seedlings of a tropical tree, Copaifera aromatica, caused increases in photosynthesis under ambient CO2, but not under elevated CO2. An enhancement in the development of buds in the leaf axils followed defoliation at ambient levels of CO2. In contrast, under elevated CO2, enhanced development of buds occurred in undefoliated plants with no further enhancement in bud development due to exposure to elevated CO2. Growth of leaf area after defoliation was increased, particularly under elevated CO2. Despite this increase, defoliated plants grown under elevated CO2 were further from compensating for tissue lost during defoliation after 51/2 weeks than those grown under ambient CO2 concentrations.
The Bromeliad Microcosm and the Assessment of Faunal Diversity in a Neotropical Forest1
Authors: Richardson Barbara A.
Published: March 2006

The faunas of tank bromeliads were sampled over two years in three forest types at different elevations in the Luquillo Experimental Forest, Puerto Rico, and the diversity of their animal communities compared. Bromeliad plants behaved as islands in that, within forests, the species richness and abundance of their animal communities were significantly and positively correlated with increase in plant size. The amount of canopy debris they accumulated was similarly correlated with increase in plant size. Overall diversity was lowest in the dwarf forest, where plants were uniformly small. Animal communities were stable from year to year, and could be characterised for each forest type and for compartments within the plant. They showed a pattern of high dominance, which increased with elevation (Mc‐Naughton index 37, 54, and 73, respectively, for the tabonuco, palo Colorado, and dwarf forest). Alpha‐diversity for sites sampled in each year reflected net primary productivity (NPP) of the forest, declining with increasing elevation when animal abundance measures were used (jackknife estimates of Simpson's diversity index 6.54 & 11.04 [tabonuco], 3.53 & 6.22 [palo Colorado], and 2.75 & 2.17 [dwarf forest]). Species richness over the two years, however, was highest in the intermediate palo Colorado forest (187 species), compared to 146 and 88 in the tabonuco and dwarf forests, respectively. These figures were close to jackknife estimates of maximum species richness. The difference in species richness between tabonuco and palo Colorado forests was significant in one year only. In addition to NPP, other factors, such as litter quality and the structural complexity of the habitat in the palo Colorado forest, may have influenced species richness. The most abundant species in individual plants were also the most widely occurring, confirming known patterns of abundance and distribution in other functional groups. Diversity within bromeliad microcosms at different elevations supported known relationships between diversity, productivity, and habitat complexity along gradients and was not related to differences in the total bromeliad habitat available for colonization.
Sampling Effects on Food Availability Estimates: Phenological Method, Sample Size, and Species Composition1
Authors: Hemingway Claire A. , Overdorff Deborah J.
Published: March 2006

It is currently recognized that the method used to collect phenology data can affect the resulting pattern. However, to date, the underlying influences have not been examined. To examine potential methodological biases, we investigated the effects of phenological method, sample size, and species composition on phenological patterns using data collected to estimate food availability for three primate species in Ranomafana National Park, Madagascar. Two phenological methods were compared: selected tree observations and systematic transect monitoring. By generating bootstrapped subsamples derived from the transect tree data set, we simulated two selected tree data sets and subsequently compared the observed and bootstrapped values. Although the observed values fell within the bootstrapped confidence inrervals, suggesting no significant effects of sampling protocol or sample size, additional lines of evidence suggest otherwise. Observed samples composed of different plant species, whether based on species attributes such as life‐form or categories such as food versus nonfood plants, consistently produced different phenological patterns. Wide confidence intervals of the bootstrapped samples indicate high individual variation in reproductive activity within the species sampled. Finally, we compared how well the selected tree and the transect methods represented food items used by all three primate species studied and found that transect methods sampled a wider diversity of food items, including rare foods, and a higher percentage of main primate food items than selected tree methods.
Variation in Nickel Content in the Nickel‐Hyperaccumulating Shrub Psychotria douarrei (Rubiaceae) from New Caledonia1
Authors: Boyd Robert S. , Jaffré Tanguy , Odom John W.
Published: March 2006

Plants that hyperaccumulate Ni contain > 1000 ppm (dry wt.) in their tissues. Variation of Ni content within hyperaccumulating plant species is poorly explored. Using the Ni‐hyperaccumulating shrub Psychotria douarrei, we documented variation of leaf Ni levels within individual shrubs, and variation with respect to plant size and leaf age. Plant size did not correlate significantly with leaf Ni content, and leaf Ni content did not correlate significantly with soil Ni content. Older leaves contained twice as much Ni as younger leaves. Older leaves also contained greater concentrations of Ca, Fe, and Cr but less K, P, and Cu. Five elements (Zn, Pb, Co, Mn, Mg) showed no significant variation due to leaf age. We also examined the effect of leaf age on epiphyll cover, finding increased epiphyll cover on the upper surface of older leaves. The dominant leafy liverwort epiphyll had a relatively high Ni content (400 ppm), suggesting that epiphylls of Ni hyperaccumulators obtain some Ni from host leaves. Individual shrubs differed in mean leaf Ni content almost two‐fold (14,900‐27,700 ppm). Variation among branches within individuals also ranged widely; however, this intraplant variability was not strongly correlated with the mean leaf Ni content of an individual shrub. We concluded that Ni contents in leaves of P. douarrei vary considerably due to leaf age, among individual shrubs, and among branches within a shrub.
Dispersal of Amazonian Trees: Hydrochory in Swartzia polyphylla1
Authors: Williamson G. Bruce , Costa Flávia , Vera Carolina V. Minte
Published: March 2006

Hydrochory was investigated in the seeds of the Amazonian floodplain tree, Swartzia polyphylla, in which pods open on the tree to release one large seed. Seeds collected from beach drift along the Rio Negro showed a high percentage of floaters (82%). Yet most seeds sank following collection from: adult trees (89%), unflooded ground under adults (96%), and flooded ground under adults (86%). The specific gravity of the seeds was near that of water, 1.04 ± 0.03 for sinkers and 0.98 ± 0.02 for floaters. The ability to float was correlated directly with the volume of the air pocket between the two cotyledons, which varied from 5.6 to 20.5 percent of the total seed volume. In a long‐term floatation test lasting 81 days, 45 percent of the seeds never floated, 33 percent always floated, and 22 percent first sank for one week and then floated for at least one month. Seeds that never floated eventually rotted, but not until days 63‐73. Seeds that were floating at day 81, regardless of how long they had been floating, were placed on moistened filter paper for 18 days during which time 36 percent germinated, 45 percent rotted, and 19 percent did neither but remained viable. These results suggest that S. polyphylla achieves dimorphism in flotation of its seeds, some sinking and some floating, by producing seeds of continuous variation in specific gravity around a mean close to 1.00. Seeds that float can be dispersed long distances along river margins, while those that sink may be moved only marginally from the parent tree.
Seed Dispersal by Bats and Birds in Forest and Disturbed Habitats of Chiapas, Mexico1
Authors: Medellin Rodrigo A. , Gaona Osiris
Published: March 2006

We examined seed dispersal by bats and birds in four habitats of the Selva Lacandona tropical rain forest region, Chiapas, Mexico. The four habitats represented a disturbance gradient: active cornfield, ten‐year‐old abandoned cornfield, cacao plantation, and forest. Using seed traps examined before sunrise (0400 h) and before sunset (1800 h), we compared volant vertebrate seed dispersal, assuming that seeds found at the end of the night were dispersed by bats and those found at the end of the day were dispersed by birds. We did not find seeds from other frugivores such as monkeys or opossums. In all habitats bats dispersed more seeds than birds. In most months bats also dispersed more seeds than birds, except in December when no seeds were found in the traps. Bats also consistently dispersed more species of seeds than birds, although a x2 comparison showed differences not to be significant. Fifty percent of the species represented in the dispersed seeds in all habitats were pioneer species. Cecropia seeds represented a high percentage (up to 87% of those dispersed by bats and up to 83% by birds) of dispersed seeds that fell in our traps. The influence of bats and birds on secondary successional processes is likely to be fundamental for the establishment of vegetation. Since bats dispersed more seeds than birds (primarily to disturbed areas and consisting primarily of pioneer species), they are likely to play an important role in successional and restoration processes among habitats as structurally and vegetationally different as cornfields, old fields, cacao plantations, and forest.
Feeding Ecology of the Giant Otter, Pteronura brasiliensis1
Authors: Rosas Fernando C. W. , Zuanon Jansen A. S. , Carter Sarah K.
Published: March 2006

The food habits of the giant otter, Pteronura brasiliensis, were determined by analyzing fecal samples collected year–round from communal latrines at Xixtiaú Creek (00°48'S, 61°33'W), Jauaperi River (central Brazilian Amazon) between 1993 and 1994. Communal latrines were also sampled during the low water season at Aquidauana River (19°32'S, 56°40'W), Pantanal of Mato Grosso do Sul (central Brazil). Fragments of vertebrae, mandibles, teeth, scales, and fin spines provided an estimate of the diet composition. Remains of fish were present in all of the samples. The main fish groups found at Xixuaú Creek were Perciformes, represented specifically by Cichlidae (97.3% of all samples), Characiformes (86.5%) and Siluriformes (5.4%). The Characiformes were represented mainly by E, rythrinidae (Hoplias sp. 90.6%), followed by Serrasalmidae (28%). The Anostomidae occurred with a frequency of 18.7 percent, while Characinae, Bryconinae, and Cynodontidae were only observed in 3.1 percent of the Characiformes records. At Aquidauana River, the Characiformes were the most frequent fish group, represented in 100 percent of all samples, followed by Siluriformes (66.6%) and Perciformes (33.3%). The fish from the main groups identified in the diet of the giant otters prefer riverbanks, lakes, and flooded forests. The feeding habits of Pteronura brasiliensis are probably influenced by the vulnerability and abundance of the prey consumed by this carnivore.
Early Plant Succession in Abandoned Pastures in Ecuador1
Authors: Zahawi R. A. , Augspurger C. K.
Published: March 2006

We compared early plant succession in four abandoned pastures of differing age since abandonment and a nearby secondary forest site in northwestern Ecuador. Two “Open” pastures had no tree canopy covering, and two “Guava” pastures had a well‐developed canopy cover of Psidium guajava. No site had been seeded with pasture grasses. All pastures were compared in a chronological sequence; two were monitored for 18 months. Species richness was consistently higher in Guava sites than in Open sites and it continued to increase over time, whereas it remained static in Open sites. Species richness was highest in secondary forest. Recruitment of tree saplings in Guava sites was lower than in secondary forest; however, it was nearly absent in Open sites. The seed bank contained predominantly herbaceous species at all sites, and was highly dissimilar to aboveground vegetation. Dominance‐diversity curves for Guava sites showed a more equitable distribution of species that increased over time. In contrast, dominance‐diversity curves for Open sites were static and indicated dominance by a few aggressive species. Soil characteristics among sites were variable; however, a principal components analysis on soils isolated the older Open site from all others. The older Open site had the lowest species richness and was dominated by Baccharis trinervis, an aggressive shrub species. The site appears to be in a state of arrested succession and some form of restorative intervention may be necessary to initiate succession toward a forested condition. Succession in Guava sites appears headed toward secondary forest, whereas it does not in Open sites.
Single‐Seeded Fruits and Seedling Establishment in Dalbergia miscolobium Benth. (Papilionaceae)1
Authors: Sassaki Regina Miyuki , Felippe G.M.
Published: March 2006

Dalbergia miscolobium (Papilionaceae) is a tree of the Brazilian cerrado that produces ovaries with two ovules. Only one ovule usually matures, but when two mature, they are smaller than seeds of single‐seeded pods. Germination percentage was lower in small seeds than in medium or large seeds. In general, small seeds gave rise to smaller seedlings (dry mass) than did medium and large seeds. The root/shoot ratio, however, was very similar for the first six months, indicating that this ratio is consistent across seedling sizes. There was no correlation between seed size and relative growth rate. Single‐seeded fruit production in D. miscolobium resulted in greater seed reserves and increased fruit dispersal distance; single‐seeded fruits were lighter than double‐seeded ones. Together, these two features should increase the probability of successful seedling establishment of seeds from single‐seeded versus double‐seeded fruits.
Pollination Ecology and Effect of Nectar Removal in Macleania bullata (Ericaceae)1
Authors: Navarro Luis
Published: March 2006

The floral syndrome of Macleania bullataYeo (Ericaceae) reflects its adaptation to hummingbird pollination. Its flowers, however, are subject to high levels of nectar robbing. I examined the floral visitor assemblage of M. bullata in a tropical montane wet forest in southwestern Colombia, focusing on the behavior of the visitors. I also tested for the presence of nocturnal pollination and the effects of nectar removal on new nectar production. The principal floral visitors were the nectar robbing hummingbirds Ocreatus underwoodii (19.1% of visits) and Chlorostilbon mellisugus (18.9%). Only two species of long–billed hummingbirds visited the flowers of M. bullata as “legitimate” pollinators: Coeligena torquata (14.7% of visits) and Doryfera ludoviciae (14.3%). The remaining visits constituted nectar robbing by bees, butterflies, and other species of hummingbirds. Nocturnal pollination took place, although fruit set levels were 2.4 times higher when only diurnal pollination was allowed as opposed to exclusively nocturnal pollination. Nectar robbers removed floral nectar without pollinating the flower. Treatments of experimental nectar removal were carried out to examine if flowers synthesize more nectar after nectar removal. Nectar removal increased the total volume of nectar produced by each flower without affecting sugar concentration. Thus, nectar robbing can impose a high cost to the plants by forcing them to replace lost nectar.
Behavioral and Physiological Differences between Two Parapatric Heliconius Species1
Authors: Davison Angus , McMillan W. Owen , Griffin Ashleigh S. , Jiggins Chris D. , Mallet James L. B.
Published: March 2006

The behavior and physiology of two parapatric sibling species,i Heliconius erato cyrbiaGodt. andH. himeraHew., were investigated to assess if environmental adaptation enabled stable morphological, genetic, and ecological differences to exist in the face of hybridization. Morning and evening activity, egg production, and larval development time ofH. himeraandH. eratoin insectaries were recorded; individuals were collected in allopatry and in sympatry from a hybrid zone in which the species overlapped. Studies were performed at ambient conditions within the natural range ofH. himera. H. himerawas considerably more active thanH, eratoflying earlier in the morning and later in the evening, even when both species were collected in sympatry. Similarly,H. himeralaid more eggs, and the hatched larvae developed more rapidly. The results suggest that physiological constraints are an important selective force that may have been important in speciation and counteracts hybridization in the maintenance of theH. himeral H. eratocontact zone. Ecological selection, arising from adaptation to low temperatures, may help explain the competitive exclusion ofH. eratobyH. himerain the drier, cooler montane habitat favored by the latter species.
Diversity and Abundance of Litter Frogs in a Montane Forest of Southeastern Brazil: Seasonal and Altitudinal Changes1
Authors: Giaretta A. A. , Facure K. G. , Sawaya R. J. , Meyer J. H. De M. , Chemin N.
Published: March 2006

We sampled litter frogs in an 1800‐ha mid‐elevation seasonal forest in southeastern Brazil. One hundred 8 * 8‐m plots were sampled during the dry/cold season and wet/warm season (unburned areas); we also examined the effects of fire in recently burned areas. A total of 267 frogs (305 g), belonging to 16 species (4 families) were caught. A single species comprised 78.5 percent of the individuals in the dry/cold season and 54.3 percent in the wet/warm season. The density of individuals did not change significantly with season, biomass did. Density and biomass of frogs were positively correlated with altitude. A Mantel test indicated that biological data (species and their abundance) were significantly associated with environmental parameters. The burned areas showed low values in richness, density and biomass of frogs. Harsh seasonal climate and a history of human disturbance may produce the low observed diversity values. The greater densities of frogs in sites of higher elevation may primarily result from mist‐generated humidity, which diminishes the harshness of the dry/cold season in relation to lower sites.
Home Range, Population Density, and Food Resources of Agouti paca (Rodentia: Agoutidae) in Costa Rica: A Study Using Alternative Methods1
Authors: Beck–King Harald , Helversen Otto von , Beck–King Rachel
Published: March 2006

Field studies of elusive mammals such as Agouti paca are difficult, and results are often biased and incomplete because the animals are nocturnal and avoid traps. By studying an A. paca population in a Pacific lowland forest of Costa Rica, we developed indirect observational methods to estimate population density and food resource utilization. To estimate population density, we divided the number of A. paca burrows found in a 12‐ha census area by the average number of burrows utilized per individual from radiotelemetry data. We compared this estimate to independent population estimates obtained using two transect methods. Agouti paca density was estimated at 93 individuals/km2 based on burrow number, and between 67 to 70 individuals/km2 using transect methods. This discrepancy corroborates previous studies suggesting that transect methods underestimate population density. To identify food resources consumed by the species, we collected fruits and seeds with unambiguous A. paca teeth marks. The only animal in Central America with an incisor width similar to A. paca. is Dasyprocta variegata; in a comparison of both species, however, we found that A. paca had a significantly larger incisor width and that teeth marks of 4 mm or wider unambiguously indicated handling by this species. By applying this technique, food resources utilized by A. paca can be identified more easily than by direct observation. At our study site, we identified 33 plant species consumed by A. paca; 61 percent are new records for this animal. Our results suggest that A. paca plays a major, although not fully understood, ecological role in seed predation and dispersal.
Tree Leaf Form in Brunei: A Heath Forest and a Mixed Dipterocarp Forest Compared1
Authors: Turner I. M. , Lucas P. W. , Becker P. , Wong S. C. , Yong J. W. H. , Choong M. F. , Tyree M. T.
Published: March 2006

Canopy‐top leaves of the dominant tree species from two 0.96‐ha plots in Brunei, northern Borneo, were sampled for structural and chemical analysis. Thirteen species from the mixed dipterocarp forest at Andulau and 14 from the lowland heath forest at Badas were studied. The heath‐forest species had significantly thicker leaves and were lower in nitrogen and ash concentration than those from the mixed dipterocarp forest. There were no significant differences between the two species groups in leaf mass per unit area (LMA), leaf fracture toughness, carbon concentration, 813C, neutral detergent fiber concentration, sclerophylly index, and stomatal density. A significant negative correlation between %C and 813C was found for the species from the mixed dipterocarp forest, but not those from the heath forest. The degree of sclerophylly measured in physical terms overlapped between the two sites to a considerable degree; however, all six species tested that were present in both plots had higher leaf fracture toughness in the heath forest. The possible reasons for the marked sclerophylly in the mixed dipterocarp forest are discussed.
Insights into the Witheringia solanacea (Solanaceae) Complex in Costa Rica. I. Breeding Systems and Crossing Studies1
Authors: Bohs Lynn
Published: March 2006

The Witheringia solanacea complex consists of three species, W. asterotricha, W. meiantha, and W, solanacea, native to Central and South America. The three taxa are morphologically similar, and their distinctions and relationships have been the subject of taxonomic controversy. To investigate breeding systems and potential for hybridization among the taxa of the complex, two Costa Rican accessions per species were used in a crossing program. All plants were self‐incompatible except for one accession of W. solanacea. Hybrid plants resulted from all crosses among accessions of W. asterotricha and W. solanacea. Most crosses were unsuccessful using W. meiantha in combination with either of the other two taxa. It is suggested that W. meiantha and W. solanacea be recognized as separate taxa, but that W. asterotricha be considered a synonym of W. solanacea.
The Importance of Where to Dump the Refuse: Seed Banks and Fine Roots in Nests of the Leaf‐Cutting Ants Atta cephalotes and A. colombica1
Authors: Farji‐Brener Alejandro G. , Medina Claudia A.
Published: March 2006

The location of the nutrient‐rich organic refuse produced by a leaf‐cutting ant colony varies among ant species. Atta cephalotes locate their organic refuse in subterranean chambers, whereas A. colombica place their organic refuse on the soil surface near the nest. We studied the effect of the absence or presence of external organic refuse on the abundance of fine roots and seed bank composition in the superficial horizons of ant nests. We sampled soils from ant nests or dumps and adjacent areas of 15 adult nests of A. cephalotes at La Selva (LS), Costa Rica, and of 15 of A. colombica nests on Barro Colorado Island (BCI), Panama. Soils from A. cephalotes nests did not differ from adjacent soils in abundance of fine‐root and seed diversity. In contrast, organic refuse from A. colombica nests was less diverse in seed composition (due to the great abundance of Miconia argentea) and had a greater abundance of fine roots than adjacent areas. Thus the external location of the ant‐nest organic refuse is potentially important in determining the different types of plant recolonization in abandoned or dead ant nests. The relative abundance of these Atta species may influence the structure and/or composition of tropical forests.
Roosting Behavior of Colonial and Solitary Flying Foxes in American Samoa (Chiroptera: Pteropodidae)1
Authors: Brooke Anne P. , Solek Christopher , Tualaulelei Ailao
Published: March 2006

We examined characteristics of roosting sites utilized by two flying fox species (Pteropus tonganus and P. samoensis) in American Samoa. The colonial roosting sites of P. tonganus were observed over a ten‐year period, including two years when severe hurricanes devastated bat populations and destroyed roost trees. Prior to the hurricanes, roosts were located on cliff faces above the ocean or steep mountainsides, locations that were either inaccessible to people or in protected areas where hunting was not allowed. In the years immediately following the hurricanes, P. tonganus colonies split into smaller groups that moved frequently to different locations. Four years after the second hurricane, colonies had coalesced and returned to many of the traditional roosting sites used before the hurricanes. Common tree species in upland and coastal forest were selected as roosts. The isolated locations selected for P. tonganus roosts were apparently the result of hunting pressure on the colonies. The solitary roosts of P. samoensis were observed during 29 months. Roosting bats were well concealed and hard to detect within the forest; even bats on exposed branches were cryptic. Mature primary forest was favored as roosting habitat. Individual bats used specific branches or trees as roosts and returned to them for up to 29 months. Unlike P. tonganus, people did not alarm roosting P. samoensis easily and some roosts were located near houses and along roads.
Leaf Phenology and Leaf Damage of Saplings in the Luquillo Experimental Forest, Puerto Rico1
Authors: Angulo‐Sandoval Pilar , Aide T. Mitchell
Published: March 2006

Changes in light or water availability can result in synchronous leaf production, concentrating food availability for herbivores of young leaves to only a few months. To determine the importance of food availability on herbivory, leaf phenology and leaf damage were studied in the Luquillo Experimental Forest (LEF) of Puerto Rico. We studied 20 individuals of eight species for two years. Every month, new leaves were marked; the following month, leaf area and area of damage were measured. Over two years, comparison of leaf production and percent herbivory were performed for each species, and for all species taken together. More than 30 percent of the annual leaf production occurred in May and June. Leaf production was associated with an increase in PFD (photon flux density) and was not related to the patterns of rainfall. Although leaf production was synchronous, there were no differences in herbivory between the peak and non‐peak periods of leaf production. Possible explanations for the constant levels of herbivory throughout the year are the presence of a generalist herbivore community, the ability of herbivores to track changes in food availability, or high densities of herbivore predators that control herbivore populations.
Monodominance in an African Rain Forest: Is Reduced Herbivory Important?1
Authors: Gross Nicole D. , Torti Sylvia D. , Feener Donald H. , Coley Phyllis D.
Published: March 2006

Tropical monodominant forests in which one tree species dominates the canopy occur in all three major tropical regions, but few studies have focused on the mechanisms responsible for dominance. This study tests the hypothesis that relative to other species in the community, dominant species are well defended and escape herbivore and pathogen damage. We surveyed the rate of damage on young expanding leaves of seedlings and saplings belonging to eight species within both monodominant Gilbertiodendron dewevrei forests and adjacent mixed–species forests in eastern Congo. Results showed that escape from herbivore and pathogen damage is not a mechanism by which Gilbertiodendron achieves dominance, as it suffered the highest damage level of any species surveyed. Similarly, other sub–dominant common species also suffered high rates of damage. These results are discussed in relation to the phenolic, fiber, and nitrogen content of leaves, and in the context of current theories pertaining to plant–herbivore interactions.
Do Lecythidaceae Specialists (Coleoptera, Cerambycidae) Shun Fetid Tree Species?1
Authors: Berkov Amy , Meurer‐Grimes Barbara , Purzycki Kenneth L.
Published: March 2006

Characteristic secondary metabolites are currently acknowledged to play a pivotal role in the circumscription of a plant's insect fauna. A newly discovered association between wood–boring longicorn beetles (Cerambycidae) and their host trees belonging to the Brazil nut family (Lecythidaceae) inspired a yearlong rearing project in the lowland Neotropical rain forest of central French Guiana. Branches severed from five species of Lecythidaceae yielded 1813 cerambycids belonging to 37 species. Two of the five tree species, Couratari stellata and Gustavia hexapetala, yielded impoverished complements of cerambycids that included large percentages of generalists. Both tree species are characterized by fetid odors. Wood samples collected from the malodorous C. stellata, as well as from two well–colonized species, Lecythis poiteaui and Eschweilera coriacea, were analyzed for their volatile components. Sulfur compounds accounted for almost 15 percent of the volatiles detected from C. stellata, while they were at most minor components of the two well–colonized tree species. S–methylmethionine, isolated from a C. stellata wood sample, appeared to be the major sulfur compound contributing to the distinctive smell. We hypothesize that this foul odor is a deterrent to specialist cerambycids seeking oviposition sites.
Frugivoría por Aves en un Paisaje Fragmentado: Consecuencias en la Dispersión de Semillas1
Authors: Ortiz‐Pulido Raúl , Laborde Javier , Guevara Sergio
Published: March 2006

Existen pocos datos sobre la dispersión de semillas por aves frugivoras en paisajes fragmentados que se originaron de selvas tropicales secas, en comparación a los existentes para selvas tropicales húmedas. En este trabajo evaluamos el efecto de las aves frugfvoras en un paisaje fragmentado localizado en Veracruz, México, ocupado actualmente por remanentes de selvas mediana y baja, pastizal, y matorrales sobre dunas de arena. Para ello determinamos cuatro caracteristicas para el paisaje relacionadas con la dispersión de semillas por aves: especies de aves y plantas interactuantes, caracterfsticas de estas especies, variabilidad espacio‐temporal en la dispersión, y resultado de la interacción. Durante un año registramos 54 especies de aves y 33 especies de plantas que realizaron 176 interacciones frugivoro–ornitócoro diferentes. La similitud (Indice de Sorensen) entre las comunidades de aves frugivoras entre tipos de vegetación fue alta (>70%), sugiriendo que muchas especies de aves usan todos los tipos de vegetatión. Por el contrario la similitud entre las comunidades de plantas ornitócoras fue comúnmente baja (<37%), sugiriendo que muchas especies de plantas están restringidas a sitios particulares del paisaje. A nivel paisaje y en la selva mediana, detectamos una relatión positiva significativa (Prueba de Spearman > 0.65, P < 0.05) entre la riqueza mensual de las comunidades de aves frugivoras y plantas ornitócoras con frutos maduros. Encontramos que muchas de las especies de plantas detectadas en estudios previos de lluvia de semillas de la zona son consumidas por aves. Las semillas zoocoras llegando a las selvas de la zona son principalmente producidas en estos tipos de vegetación (i.e., autóctonas) y las que llegan al pastizal y matorrales sobre dunas de arena son producidas en otros sitios (i.e., alóctonas) y generalmente de especies leñosas. Las aves son importances dispersoras de semillas entre los diferentes tipos de vegetación de este paisaje fragmentado, pero su efecto es distinto en cada uno de ellos. El haber determinado las cuatro caracteristicas del paisaje nos permitio detectar patrones espaciales y temporales que de otra manera hubieran permanecido ocultos.
The Flight Heights of Chalcid Wasps (Hymenoptera, Chalcidoidea) in a Lowland Bornean Rain Forest: Fig Wasps are the High Fliers1
Authors: Compton Stephen G. , Ellwood Martin D. F. , Davis Andrew J. , Welch Kathleen
Published: March 2006

Tropical rain forests are characterized by their rich plant diversity and highly diverse insect faunas containing mainly rare species. Phytophagous and parasitoid insects utilizing such fragmented resources often must travel considerable distances to find suitable hosts. For small, weak‐flying insects, entry into the fast‐flowing air above the canopy can provide one way by which long‐distance dispersal is achieved. Using sticky traps placed at different heights in a lowland rain forest of Borneo, we compared the diurnal and nocturnal flight heights of chalcids, a group of mainly very small parasitoids and phytophages, to determine if the air above the canopy was used for dispersal. Most families were represented throughout the range of trap heights, including those above the general canopy. A higher proportion of individuals were trapped above the canopy at night than during the day. Fig wasps were exceptional in that they were trapped almost entirely above the canopy. They included species associated with host trees that do not fruit in the canopy, suggesting that these short‐lived, slow‐flying insects actively fly up above the canopy and then use the wind to passively carry them the long distances needed to reach their highly localized and ephemeral hosts. Once the fig wasps detect the species‐specific volatiles released by their host figs, they then may fly down into the canopy, where the lower wind speeds would allow them to fly actively upwind to their hosts.
Introduction: The Brazilian Atlantic Forest1
Authors: Morellato L. Patricia C. , Haddad Célio F. B.
Published: March 2006

The year 2000 marks 500 years of massive destruction for the Brazilian Atlantic Forest, as a consequence of the European colonization of Brazil. Today, the Atlantic Forest is restricted to ca 98,800 km2 of remnants, or 7.6 percent of its original extension. The Atlantic Forest continues to suffer under severe anthropogenic pressure, risking imminent extinction of the remaining species. Our current knowledge indicates that this complex biome contains a species diversity higher than most of the Amazon forests, and also has high levels of endemism. The 13 selected articles in this special issue present data on the natural history, ecology, sustainable management, and conservation of the Atlantic Forest. These articles represent a sample of the research conducted to date in the region and suggest avenues of future research, particularly with regard to conservation alternatives for the remaining portions of the Atlantic Forest. This special issue represents one of the first general references pertaining to the Brazilian Atlantic Forest.
Frugivory by Toucans (Ramphastidae) at Two Altitudes in the Atlantic Forest of Brazil1
Authors: Galetti Mauro , Laps Rudi , Pizo Marco A.
Published: March 2006

Toucans are prominent components of the tropical American avifauna. Although these birds are very conspicuous, there are few ecological studies focusing on them. In this study, the diets of four sympatric toucans (Ramphastos vitellinus, R. dicolorus, Selenidera maculirostris, and Baillonius bailloni) were assessed by recording feeding bouts at two altitudes in the Atlantic Forest of southeast Brazil. Our results show that toucans are predominantly frugivorous birds (96.5% of the 289 feeding bouts were on fruits). In the lowlands (70 m elev.), only fruits (48 species, 27 families) were recorded, while in the highlands (700 m elev.), toucans were observed feeding on fruits (25 species, 22 families), flowers, leaves, and insects. Non‐fruit items were recorded only in the highlands, most of them eaten by B. bailloni. Cecropia glaziovii and Euterpe edulis, two abundant plants in the highland and lowland sites, respectively, and Virola oleifera, a plant that produces lipid‐rich arillate fruits, were eaten heavily by the toucans. The number of feeding bouts recorded for R. vitellinus in the lowlands was positively correlated with lipid content of the fruits eaten. The diameters of fruits eaten by toucans varied greatly (range = 0.4–25.0 mm). While the large Ramphastos species not only ate tiny fruits (e.g., Hyeronima alchorneoides) but also large ones (e.g., Virola gardneri), the toucanets ate piecemeal the large fruits that exceeded their gape width, suggesting that gape size did not limit the use of any fruit by the toucans at our study sites.
The Use of Fruits and Seeds by Ants in the Atlantic Forest of Southeast Brazil1
Authors: Pizo Marco A. , Oliveira Paulo S.
Published: March 2006

Given the abundance of litter‐foraging ants and fallen fleshy diaspores on the floor of tropical forests, interactions involving them should be common and may render important consequences for the biology of the diaspores. In this study, we surveyed the interactions between ants and non‐myrmecochorous diaspores along a 5‐km transect in a lowland Atlantic rain forest of southeast Brazil. A diaspore is defined as any seed, fruit, or infructescence that constitutes the unit of dispersal of the plant. During two years of monthly samplings of naturally fallen diaspores, 886 ant– diaspore interactions involving 36 ant species and 56 different species of diaspores (range = 0.05–29.5 g) were recorded. The number of interactions was significantly and positively correlated with rainfall but not with mean temperature. The number of ant species recorded in the interactions was positively associated with both rainfall and temperature. Lipid‐rich diaspores attracted a larger ant assemblage than those with lower contents of lipids. The seasonal pattern for ant‐diaspore interactions in the Atlantic rain forest is predicted by well known seasonal patterns in ant activity and diaspore production. Other factors that also may affect the observed pattern are the massive and episodic fruiting of some plant species in which diaspores are especially attractive to ants, and a preference for lipid‐rich arillate seeds. Interactions between ants and fallen non‐myrmecochorous diaspores may be especially common in lowland rain forests in which the abundance of ants is coupled with the year‐round availability of fleshy diaspores.
Cave Faunas in the Atlantic Tropical Rain Forest: Composition, Ecology, and Conservation1
Authors: Trajano Eleonora
Published: March 2006

I present a comparative analysis of the cave fauna composition for two karst areas in the Atlantic tropical rain forest: the extensively studied Ribeira Valley, southeastern Brazil, and the small and poorly known Rio Pardo region, southern Bahia state, northeastern Brazil. These regions also are compared to other Brazilian karst areas. The cave fauna from Rio Pardo appears to be more similar to the fauna of other tropical caves in the Caatinga and Cerrado domains than to the cave fauna of the subtropical Ribeira Valley. Ecological data, including probable trophic relationships, are presented, and special conservation problems related to karst areas, with examples from the Atlantic rain forest cave taxa, are discussed.
Atlantic Forest Butterflies: Indicators for Landscape Conservation1
Authors: Brown Keith S. , Freitas André Victor L.
Published: March 2006

The Atlantic Forest region (wide sense) includes very complex tropical environments, increasingly threatened by extensive anthropogenic conversion (>90%). Ecologically specialized, short‐generation insects (butterflies) are evaluated here as indicators for monitoring community richness, landscape integrity, and sustainable resource use in the region. The > 2100 butterfly species in the Atlantic Forest tegion have been censused in many sites over 35 years, giving comparable daily, weekly, monthly, and long‐tetm site lists. The 21 most thoroughly studied sites include 218–914 species, of which half can be censused in a week or less. The butterfly communities are divided into six relatively distinct faunal regions, centered in the northeast, the central coastal tablelands, the southeast coastal plain, the mountains plus interior of the southeastern states, the central plateau, and the southern states. Species richness shows the highest values in coastal mountains from 15 to 23°S. Local butterfly communities show a high turnover, with 20 to 40 percent of the species, especially small Lycaenidae and Hesperiidae, recorded only as unstable populations or “tourists.” Easily sampled species in the family Nymphalidae, and especially its bait‐attracted subfamilies, are best correlated with the entire butterfly fauna and can be used as surrogates for species diversity. In most butterfly groups, species richness is well predicted by landscape connectivity alone, or by composite indices of environmental heterogeneity, natural disturbance, and (negatively) anthropogenic disturbance. Principal components and redundancy analyses showed that the richness and proportions of different butterfly groups in the local fauna are variably explained by disturbance, seasonality, temperature, vegetation, soils, and landscape connectivity. Various groups thus can be used as rapid indicators of different types of change in the community, its environment, and the landscape. Threatened and rare species also can be used as indicators of the most unique Atlantic Forest communities (paleoenvironments), which need special attention.