bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

ABSTRACTField 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

AbstractCanopy‐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

ABSTRACTThe 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

ABSTRACTThe 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

ABSTRACTWe 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

ABSTRACTChanges 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

ABSTRACTTropical 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

ABSTRACTCharacteristic 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

RESUMENExisten 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

ABSTRACTTropical 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

ABSTRACTThe 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

ABSTRACTToucans 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

ABSTRACTGiven 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

ABSTRACTI 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

ABSTRACTThe 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.