bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluctuaciones Temporales en la Composición Floristica del Bosque Tropical Atlántico1
Authors: Rolim Samir Gonçalves , Couto Hilton Thadeu Zarate do , de Jesus Renato Moraes
Published: March 2006

Temporal and spatial changes in floristic composition over a 15‐year period in an Atlantic tropical forest in Brazil were analyzed. The data were recorded in five 0.5‐ha (50 × 100 m) plots within a 22,000‐ha forest reserve. In each plot, all stems ± 10 cm diameter at breast height (DBH) were repeatedly inventoried. The overall number of species among all plots was steady over time but changed within a given plot. In all plots, the proportion for the disappearance of species was 7 percent and that for immigration of new species into the plots was 9.5 percent. Approximately 65 percent of the disappearance occurred between 1986 and 1989, and 74 percent of the immigration happened after 1986. The observed changes in composition evidently were due to natural disturbance and climatic events, such as an unusual four‐month drought. Disappearance of species from the plots did not denote regional extinction of those species, because they persisted elsewhere in the forest reserve. The changes in species composition within the plots and persistence outside them, however, indicated that large areas are required for in situ conservation of tropical tree species. These areas must be large enough for population changes to occur without negative effects on genetic and demographic structures of tree species.

RESUMES

Foram analisadas as variações temporais e espaciais na composição florística de uma floresta tropical num período de 15 anos entre os anos de 1980 e 1995. Em 5 parcelas de 0.5 ha (50 × 100 m) amostraram‐se todas as árvores com diàmetro a altura do peito (DAP) ≥ 10 cm. Para a escala e período que este estudo abrangeu pode‐se concluir que há uma estabilidade no número de espécies da comunidade ao longo do tempo e esta estabilidade foi significativamente afetada por um distúrbio natural (um período seco de 4 meses) ocorrido em 1987. Foi constatado que em 15 anos desapareceram 7 por ciento das espécies nas parcelas monitoradas, contra um total de 9.5 por ciento de novas espécies recrutadas. Aproximadamente 65 por ciento do desaparecimento de espécies ocorreu entre 1986 e 1989 e 74 por ciento das novas espécies foram recrutadas apos 1986. O desaparecimento não significa necessariatmente um fenômeno de extinção e foi demonstrado que as espécies continuam ocorrendo na comunidade. O desaparecimento de espécies dentro das parcelas e sua pcrsisténcia fora delas indica que são necessárias grandes áreas para conservação in situ de espécies arbóreas. Estas áreas devem ser capazes de absorver as flutuaçz̃oes populacionais sem afetar a estrutura genética e demográfica das espécies.
Detrital Fruit Processing in a Hawaiian Stream Ecosystem1
Authors: Larned Scott T. , Chong Charles T. , Punewai Noelani
Published: March 2006

In temperate forested streams, fruit from riparian trees is generally a minor and seasonal component of the allo‐chthonous detritus. In contrast, riparian fruit input to tropical streams is often high and continuous. Detrital fruit is abundant in some forested Hawaiian streams compared to other forms of riparian detritus, and rates of leaf litter processing by macroscopic invertebrates are very low. These observations suggested that fruit is an important food resource for detritivores. A microcosm system was used to measure the rates at which two common detrital fruits, guava and mango, were processed by two common detritivores, the prawn Macrobrachium lar and the gastropod Tarebia granifera. Comparisons of fruit weight loss rates normalized by detritivore weight indicated that M, lar processed guavas at significantly higher rates than T. granifera, differences in rates of mango processing by M. lar and T. granifera were not significant. Microcosms containing both M. lar and T. granifera were used to test for interactions between the invertebrates that affected rates of mango processing. No interspecific interactions were detected. A field study was conducted in Kaiwiki Stream, Island of Hawaii, to determine rates of detrital fruit input and export. Detrital fruit was supplied to the study area year‐round, with peaks corresponding to summer and autumn fruiting seasons. Guavas and mangos accounted for 85 percent of the fruit biomass entering the stream and 92 percent of the fruit exported from the stream. Mean daily export rates of guava were 7 percent of input, and export rates of mango were 5 percent of input. These measurements suggested that most of the fruit entering the stream is retained and comprises a substantial food resource for detritivores. Comparisons of the biomass‐specific rates at which M. lar and T. granifera processed mangos and guavas with the rates at which mangos and guavas entered Kaiwiki Stream suggested that these invertebrates can process most of the detrital fruit in the stream.
Tropical Rain Forest Recovery from Cyclone Damage and Fire in Samoa1
Authors: Hjerpe Johan , Hedenâs Henrik , Elmqvist Thomas
Published: March 2006

In 1990 and 1991, Samoa was struck by two cyclones, Ofa and Val. In the Tafua Rain Forest Preserve on the island of Savai'i, one part of the forest also burned after the first cyclone. Here we report on patterns of regeneration and changes in tree species composition in the Tafua lowland rain forest after five years of recovery from cyclone and fire disturbance. In the unburned area, tree canopy cover increased from 27 percent after the last cyclone to 58 percent, and in the burned area from below 12 to 49 percent. Nine of the ten most common tree species decreased in relative abundance in the entire forest after the last cyclone. One fast growing pioneer species, Macaranga harveyana now makes up 42 percent of the total number of trees (>5 cm DBH) in the unburned area and 86 percent in the burned area. Large interspecific differences occur in size distribution and there are at least four distinguishable regeneration patterns, which may be related to shade tolerance. Mean number of species per plot was generally higher in the unburned area than in the burned area, while the Shannon evenness index was higher in the unburned than in the burned area only for trees above 1 cm DBH. Species with fruits known to be fed upon by birds and/or bats generally made up a larger proportion of all trees in the burned than in the unburned area. In contrast to other studies of post‐cyclone regeneration, in which recovery is often rapid due to resprouting of trees, recovery in the Tafua forest was a slow process with regeneration more dependent on vertebrate seed dispersal than on resprouting.
Removal of Nonnative Vines and Post‐Hurricane Recruitment in Tropical Hardwood Forests of Florida1
Authors: Horvitz Carol C. , Koop Anthony
Published: March 2006

In hardwood subtropical forests of southern Florida, nonnative vines have been hypothesized to be detrimental, as many species form dense “vine blankets” that shroud the forest. To investigate the effects of nonnative vines in post‐hurricane regeneration, we set up four large (two pairs of 30 X 60 m) study areas in each of three study sites. One of each pair was unmanaged and the other was managed by removal of nonnative plants, predominantly vines. Within these areas, we sampled vegetation in 5 X 5 m plots for stems 2 cm DBH (diameter at breast height) or greater and in 2 X 0.5 m plots for stems of all sizes. For five years, at annual censuses, we tagged and measured stems of vines, trees, shrubs and herbs in these plots. For each 5 X 5 m plot, we estimated percent coverage by individual vine species, using native and nonnative vines as classes. We investigated the hypotheses that: (1) plot coverage, occurrence and recruitment of nonnative vines were greater than that of native vines in unmanaged plots; (2) the management program was effective at reducing cover by nonnative vines; and (3) reduction of cover by nonnative vines improved recruitment of seedlings and saplings of native trees, shrubs, and herbs. In unmanaged plots, nonnative vines recruited more seedlings and had a significantly higher plot‐cover index, but not a higher frequency of occurrence. Management significantly reduced cover by nonnative vines and had a significant overall positive effect on recruitment of seedlings and saplings of native trees, shrubs and herbs. Management also affected the seedling community (which included vines, trees, shrubs, and herbs) in some unanticipated ways, favoring early successional species for a longer period of time. The vine species with the greatest potential to “strangle” gaps were those that rapidly formed dense cover, had shade tolerant seedling recruitment, and were animal‐dispersed. This suite of traits was more common in the nonnative vines than in the native vines. Our results suggest that some vines may alter the spatiotemporal pattern of recruitment sites in a forest ecosystem following a natural disturbance by creating many very shady spots very quickly.
Pollination and Predation Limit Fruit Set in a Shrub, Bourreria succulents (Boraginaceae), after Hurricanes on San Salvador Island, Bahamas1
Authors: Rathcke Beverly J.
Published: March 2006

Hurricanes have been assumed to reduce the reproduction of plants, either directly by leaf stripping and stress or indirectly by reducing pollinators. I examined the pollination and fruit set of a common shrub, Bourreria succulenta, after hurricanes on San Salvador island, Bahamas. Contrary to the assumption of resource limitation, B. succulenta showed unusually prolific flowering after Hurricane Lili stripped leaves from most of the plants in October 1996. I predicted that the abundant flowering would saturate pollinators and that fruit set would be pollination‐limited. Fruit set was strongly pollination‐limited by 71 percent. Butterflies are probably the major pollinators and were present at the site, but they rarely visited B. succulenta flowers even though flowers were brimming with nectar. Nectarivorous birds (Bananaquits and Bahama Wbodstars) visit B. succulenta flowers, but their populations were decimated by Hurricane Lili and they rarely visited flowers during this time. Fruit set was also severely predation‐limited; a moth caterpillar (Gelechiidae) was extremely abundant and ate buds, flowers, and fruits, causing a further 68 percent reduction in fruit set. Together, pollination limitation and predation limitation reduced fruit set to only 7 percent or less. Predation was also intense in 1999 after Hurricane Floyd and resulted in 11 percent fruit set or less. Whether or not hurricanes were the cause of limited pollinators or abundant predators, the resulting low fruit set could have population effects because hurricanes can provide opportunities for the recruitment of new plants. These results emphasize that understanding plant–animal interactions may be necessary for predicting the effects of hurricanes on plant reproductive success, which may affect subsequent recruitment. Species on small islands like San Salvador (150 km2) with relatively few species may be especially vulnerable to environmental disturbances such as hurricanes.
Mammalian Diet and Broad Hunting Strategy of the Dingo (Canis familiaris dingo) in the Wet Tropical Rain Forests of Northeastern Australia1
Authors: Vernes Karl , Dennis Andrew , Winter John
Published: March 2006

The diet of dingoes (Canis familiaris dingo) in the Australian Wet Tropics was examined by analyzing 383 dingo scats collected throughout the region for the presence of mammal prey remains. The scats yielded 29 native and 4 introduced mammal prey species from 14 families. The most important species in terms of percentage occurrence in the scats were Melomys cervinipes (22.2%), hoodon macrourus (17.0%), Perameles nasuta (12.5%), and Thylogale stigmatica (12.5%). The most important families were Muridae (37.1%), Peramelidae (29.5%), and Macropodidae (25.8%). Examination of small‐scale habitat preferences revealed species that preferentially use the forest edge ranked significantly higher in the diet than those that do not, and species that are terrestrial ranked higher in the diet than those that are arboreal. Relative abundance was also a significant factor in the ranked dietary occurrence of each species, with abundant species ranked significantly higher than those that are less abundant. These results suggest that dingoes in the Australian Wet Tropics are opportunistic predators of a wide variety of mammal species, with abundant terrestrial and forest edge‐dwelling taxa the most susceptible to predation.
Home Range Size of Sympatric Squirrel Species Inhabiting a Lowland Dipterocarp Forest in Malaysia1
Authors: Saiful A. A. , Idris A. H. , Rashid Y. N. , Tamura N. , Hayashi F.
Published: March 2006

Home range sizes and spatial overlap of four sympatric squirrel species were investigated in a lowland dipterocarp forest in Malaysia using a radio‐tracking method. The population density of Callosciurus caniceps was highest and C. notatus was next highest, while C. nigrovittatus and Lariscus insignis were scarce. C. caniceps was larger than C. nigrovittatus and C. notatus while L. insignis was extremely small. For females, home range size was smaller in L. insignis than Callosciurus spp., which may support the body weight hypothesis: larger species have larger home ranges. Among the three Callosciurus species, female C. caniceps had the smallest home range. These differences were accounted for by habitat characteristics rather than by density or body weight; C. caniceps was dominant in bushy areas and used crowded small trees while C. notatus and C. nigrovittatus used large trees in the forest. In this study, home range size did not change seasonally; this differs from studies in temperate regions, possibly because food availability is much less variable among seasons in tropical rain forest. Home range overlap among heterospecific individuals was common but different species seemed to partition space by using different vertical levels of the forest. Consequently, the home range size and spatial overlap of sympatric squirrel species may be affected by habitat diversity in tropical rain forest.
Communities of Endophytic Fungi in Leaves of a Tropical Timber Tree (Guarea guidonia: Meliaceae)1
Authors: Gamboa Miguel A. , Bayman Paul
Published: March 2006

Endophytes are microorganisms that live inside plant tissues without causing symptoms of disease. They are a largely unexplored component of biodiversity, especially in the tropics. In this study, leaves from two populations of Guarea guidonia trees (Meliaceae) in the Luquillo region, Puerto Rico, were screened for diversity and composition of en‐dophytic fungal communities. A total of 268 leaf fragments from 14 trees were surveyed. Thirty‐eight morphospecies of endophytes were found. Phomopsis, Colletotrichum, Xylaria, and Rhizoctonia‐iike fungi were the most abundant taxa. Over 95 percent of the leaf pieces had endophytes. Communities had a few abundant species and many species with few individuals. The fungal community from the Guarea population in a forest preserve was more diverse than that from a disturbed area. Fungal communities were stratified according to height within a tree, but no differences were found between blade, petiolule, and rachis. The data suggest that the smaller and the more scattered the plant fragments sampled, the higher the probability of approaching real diversity values of endophytic fungal communities.

RESUMES

Los endófitos son microorganismos que viven dentro de las tejidos vegetales sin manifestarse patológicamente. Ellos constituyen un componente poco explorado de la biodiversidad, especialmente en las zonas tropicales. En este trabajo se estudió la diversidad y composición de las comunidades de hongos endófitos en hojas de dos poblaciones del árbol Guarea guidonia (Meliaceae), en la región de Luquillo, Puerto Rico. Un total de 268 fragmentos provenientes de 14 árboles fueron muestreados, encontrándose 38 morfoespecies de hongos endófitos. Los taxones más abundantes fueron Phomopsis, Colletotrichum, Xylaria, y Rhizoctonia. Más del 95 por ciento de los fragmentos presentó endófitos; las comunidades tenían pocas especies abundantes y muchas especies raras. De las dos poblaciones de G. guidonia estudiadas, la situada en una zona más conservada fue más diversa en cuanto a su comunidad de endófitos. Se observó estratificación de acuerdo con la altura del árbol, pero no se observaron diferencias entre la lámina, el peció1ulo, y el raquis de las hojas. Los datos sugieren que entre más pequeños y esparcidos scan los fragmentos muestreados, mayor será la probabilidad de aproximarse a los valores reales de diversidad de las comunidades de hongos endófitos.
Seed Size, Seed Germination, and Seedling Survival of Brazilian Tropical Tree Species Differing in Successional Status1
Authors: de Souza Rogéria Pereira , Válio I. F. M.
Published: March 2006

Seed germination and seedling establishment patterns have been used to classify species as shade tolerant or intolerant. The main objective of this research was to investigate, under controlled conditions, seed germination of species from different successional positions as well as to follow seed germination and seedling survival under natural shade in the field. The species studied were Solarium granuloso‐leprosum, Trema micrantha, Cecropia pachystachya, Croton piptocalyx, Bauhinia forficata subsp. pruinosa. Senna macranthera, Schizolobium parahyba, Piptadenia gonoacantha, Chorisia speciosa, Pseudobombax grandiflorum, Ficus guaranitica, Esenbeckia leiocarpa, Pachystroma longifolium, Myroxylon peruiferum, and Hymenaea courbaril. Field trials were carried out at Santa Genebra Municipal Reserve, Campinas, SP, Brazil, at the forest edge and in the understory. No significant correlations were detected between successional status and seed size or seed water content. Light‐regulated germination was present only in small‐seeded species. In field experiments, most species, including the light‐sensitive ones, were able to germinate under the canopy, where a low red/far‐red ratio predominates. Most species, mainly those of early‐ and intermediate successional positions, presented low seedling survival rates under shade. Myroxylon peruiferum was the most shade tolerant species, while 5. granuloso‐leprosum, C. speciosa, P. gonoacantha, F. guaranitica, T. micrantha, and 5. parahyba were the most shade intolerant. These latter species showed little or no survival under the shade conditions.
The Fate of Attalea phalerata (Palmae) Seeds Dispersed to a Tapir Latrine1
Authors: Quiroga‐Castro Verónica D. , Roldán Alexandra I.
Published: March 2006

At the Beni Biological Station, Bolivia, we compared the fate of seeds of the palm Attalea phalerata dispersed by tapirs to a latrine with that of non‐dispersed seeds. Survival of seeds that had passed through tapir guts did not differ significantly from that of unconsumed seeds, demonstrating that tapirs are legitimate seed dispersers of A. phalerata. Experimental and observational studies showed that tapir dispersal can contribute to escape from seed predation by bruchid beetles such as Pachymerus cardo. Nevertheless, the major contribution of the dispersal process may simply be the mechanical barrier to bruchid attack represented by the fecal material covering seeds. Furthermore, total absence of seedlings and adults from the tapir latrine studied suggests that seasonally flooded tapir latrines are not safe sites for A. phalerata.

RESUMES

En la Estación Biologica del Beni, Bolivia, comparamos el destino de las semillas de la palmera Attalea phalerata dispersadas por tapires a su letrina con aquel de las semillas no dispersadas. La sobrevivencia de las semillas que pasaron por el tracto digestive de tapires no difirió significativamente de aquellas no consumidas, mostrando que los tapires son legítimos dispersores de semillas de A. phalerata. Estudios experimentales y observacionales mostraron que la dispersión de semillas por tapir puede ayudar al escape de los depredadores de semillas como el bruquido Pachymerus cardo. Sin embargo, la principal contribución del proceso de dispersión puede ser simplemente la barrera mecánica al ataque por brúquidos representada por la materia fecal que cubre a las semillas. Ademas, la ausencia total de plántulas y adultos en la letrina estudiada sugiere que las letrinas de tapir que se inunden estacionalmente no son sitios seguros para la germinación y sobrevivencia de A. phalerata.
Geographic Variation in Host Location Cues for a Dipteran Parasitoid of Paraponera clavata1
Authors: Morehead Shellee A.
Published: March 2006

Parasitoid insects face considerable trade‐offs in locating suitable hosts within complex environments. Apocephalus paraponerae (Diptera: Phoridae) locates its host ant Paraponera clavata (Formicidae: Ponerinae) using olfactory cues. Here, comparing two populations of A. paraponerae, I describe differences in host location cues between two sites, Barro Colorado Island (BCI) in Panama and La Selva Biological Research Station in Costa Rica. At La Selva, A. paraponerae uses the ant mandibular gland products 4‐methyl‐3‐heptanone and 4‐ methyl‐3‐heptanol in host location, but does not do so on BCI. I propose that higher colony density of P. clavata causes A. paraponerae to use more species‐specific cues on BCI. I also discuss how geographic variation in host location cues could lead to allopatric speciation.

RESUMES

Los insectos parasitoides enfrentan muchas dificultades cuando buscan hospederos en ambientes complejos. Apocephalus paraponerae (Diptera: Phoridae) localiza a su hormiga hospedera, Paraponera clavata (Formicinae: Ponerinae), a travéz de pistas olfativas. En este estudio describe las diferencias en los mecanismos de localizatión de hospederos en dos sitios, la Isla Barro Colorado en Panamá y La Estación de Investigacion Biológica La Selva en Costa Rica. En La Selva, A. paraponerae usa productos de la glándula mandibular (4‐metil‐3‐heptanona y 4‐metil‐3‐heptanoI) para localizar a su hospedero, pero no hace lo mismo en IBC. Considero que un mayor densidad poblacional de P. clavata hace que A. paraponerae tenga que usar pistas más específicas en IBC. Además, propongo la existencia de otros factores ecol#oAgicos y de comportamiento que pueden afectar los mecanismos de localizacion y discuto como la variación geográfica de las pistas olfativas afecta la evolución y especiacion de los linajes de parasitoides.
Patterns of Richness and Abundance in a Tropical African Leaf‐litter Herpetofauna1
Authors: Vonesh James R.
Published: March 2006

I compared species richness and habitat correlates of leaf‐litter herpetofaunal abundance in undisturbed and selectively logged forests, and an abandoned pine plantation in Kibale National Park, Uganda. I sampled 50 randomly located 25 m2 litter plots in each area during the wet and dry seasons in 1997. Ten anuran, five lizard, and three snake species were captured in plots over the study. Assemblage composition was most similar at logged and unlogged sites. The logged forest herpetofauna had higher species richness and abundance than the unlogged forest, but diversity was greater in the unlogged forest due to greater evenness. In contrast, the pine plantation site had the highest richness, abundance, and evenness of the three study sites, but species composition was distinct from the other areas. Herpetofaunal densities were significantly lower in all three areas during the dry season than in the wet season. During the dry season, soil moisture, litter mass, topography, shrub cover, and number of fallen logs were significant positive predictors of herpetofaunal presence in litter plots, but only soil moisture was significant in the wet season. The interaction of moisture and topography appears to be important in determining seasonal patterns of litter herpetofaunal distribution. Comparison of litter herpetofaunal studies across the tropics have shown that mid‐elevation faunas generally support fewer species than lowland faunas. Compared with other tropical mid‐elevation litter faunas, Kibale supports an intermediate number of species, but at lower densities than observed at any other mid‐elevation site reported in the literature.
Landscape Patterns of Tropical Forest Recovery in the Republic of Palau1
Authors: Endress Bryan A. , Chinea J. Danilo
Published: March 2006

A GIS (geographic information systems) database was constructed from aerial photographs, a vegetation map, and topographic map data of the Ngeremeduu Bay Drainage Area (NBDA), Palau, to examine relationships between upland land cover dynamics, environmental variables, and past land use. In 1992, 82.9 percent of the NBDA was forest, 16.6 percent was grassland, and 0.5 percent consisted of village areas. Between 1947 and 1992, there was a 11.2 percent reduction of grassland area primarily due to a 10.9 percent increase in forest cover. These land cover changes led to larger, more continuous stretches of forest and numerous, highly fragmented grassland patches. Significant relationships (P 0.001) were found between the spatial distribution of forest and grassland cover and slope, elevation, soil pH, and percent soil organic matter. These patterns, however, may have resulted from past farm site selection rather than from ecological relationships. Our results indicate that areas of forest expansion were significantly (P 0.001) associated with the location of abandoned agricultural communities. In addition, over 92 percent of areas of forest expansion occurred within 100 m of established forest. These results suggest that the proximity of established forest facilitate forest recovery following human disturbance.
Phenology, Sexual Expression, and Reproductive Success of the Rare Neotropical Palm Geonoma epetiolata1
Authors: Martén Silvana , Quesada Mauricio
Published: March 2006

We studied the phenology and reproductive biology of the stained glass palm Geonoma epetiolata in a premontane rain forest of Costa Rica. This understory species is endemic to Costa Rica and Panama. We followed 102 plants for two years and found that G. epetiolata is monoecious and protandrous. Flowering duration at the inflorescence level is three to six months for the male phase and two to three weeks for the female phase; this is one the most extended flowering periods reported for palms. Flowering in this palm is continuous throughout the year, both at the individual and population level. This long and continuous flowering pattern may represent an adaptation to increase the chances of reproduction in a environment of high and unpredictable rainfall. The species is self–compatible, but self–pollination is possible only when there is overlap of male and female inflorescences (38% of the cases). Only 28 percent of the stigmas of 1020 flowers received pollen grains and 20 percent developed pollen tubes in the styles. Of all the flowers produced by an inflorescence, 14 percent initiated fruit development but only 3 percent develop into mature fruits. Seventy–six percent of the initiated fruits were aborted.

RESUMES

Estudiamos la fenologia y la biología reproductiva de la palma Geonoma epetiolata en un bosque húmedo del pre‐montano en Costa Rica. Esta palma de sotobosque es endémica de Costa Rica y Panamá. Durante dos años observamos 102 plantas marcadas y encontramos que G. epetiolata es monoica y protándrica. La duración de floración a nivel de inflorescencia es de tres a seis meses para la fase masculina y de dos a tres semanas para la fase femenina, este es el período de floración más prolongado que se ha reportado para cualquier especie de palma. La floración de esta palma es continua a través del año, tanto a nivel individual como poblacional. Este partón de floración largo y continue parece representar una adaptación para aumentar las posibilidades de reproductión en un ambiente de precipitacion alta e impredecible. La especie es auto‐compatible pero la autopolinización solo es posible cuando existe traslape de flores femeninas y masculinas dentro de un mismo individuo (38% de los casos). Unicamente el 28 por ciento de los estigmas de 1020 flores analizadas recibieron granos de polen y 20 por ciento desarrollaron tubos polínicos en los estilos. De todas las flores producidas por una inflorescencia, en promedio 14 por ciento inician el desarrollo de frutos pero solo el 3 por ciento de las flores llega a producir frutos maduros. El 76 por ciento de los frutos iniciados se abortan.
Dietary Benefits of Twilight Foraging by the Insectivorous Bat Hipposideros speoris1
Authors: Pavey Chris R. , Burwell Chris J. , Grunwald Jan‐Eric , Marshall Chris J. , Neuweiler Gerhard
Published: March 2006

Although bats are nocturnal, many species emerge from roosts to forage during twilight, despite a presumed high risk of predation at this time. Here, we describe twilight foraging by a maternity colony of Schneider's leafnosed bat (Hipposideros speoris) in the dry zone of Sri Lanka and determine the dietary benefits of such behavior. Bats usually began foraging during dusk, sometimes before sunset, and also foraged during twilight in the morning. Mean use of available twilight by four radio‐tagged bats was 75 percent. Twilight foraging made up, on average, 47 percent of the total foraging time of these bats (range = 25–96%), although twilight consisted of only 12 percent of the available time between sunset and sunrise the next morning. Eight species of potential predators (7 birds and 1 mammal) were observed within a 1 km radius of the colony, of which 5 species are predicted to regularly capture bats. Bats took a wide diversity of prey (11 insect orders, including at least 27 families, and spiders) that ranged in wing length from 2.0 to 54.0 mm. Major orders in the diet were Coleoptera, Lepidoptera, and Diptera. Prey of secondary importance included Hemiptera, Hymenoptera, Isoptera, and Neuroptera. Bats captured large numbers of insects that were only available or had marked peaks in abundance during twilight. These groups included small, swarming insects (especially flies) that have peaks in flight activity at dusk and dawn, large diurnal species (especially dragonflies) that have crepuscular activity, and winged termites that emerge in swarms at dusk. Access to these insects was a clear benefit of twilight foraging.
Jaguar (Panthera onca) Food Habits in Atlantic Rain Forest of Southeastern Brazil1
Authors: Garla Ricardo C. , Setz Eleonore Z. F. , Gobbi Nivar
Published: March 2006

Between January and December 1996, the food habits of a relict population of jaguars were studied in 220 km2 Linhares Forest Preserve, which comprises much of the remaining old‐growth Atlantic Forest of Espirito Santo, Brazil. Fecal analysis indicated opportunistic feeding on 24 prey species (N= 101 scats). Mammals represented 87 percent of the total items, followed by reptiles (9.8%) and birds (2.8%). Considering prey weight, 23.4 percent of the items weighed 1–3 kg, 40.5 percent were 3–10 kg, and 27.7 percent weighed more than 10 kg. Analysis of relative prey frequency and biomass indicated that the diet was concentrated in two prey types: long‐nosed armadillo and white‐lipped peccary. Literature data suggest that forest jaguars rely on the same mammal prey over their entire geographic range.

RESUMES

Entre janeiro e dezembro de 1996, os hábiros alimentares de uma populaçáo da onga pinrada foram estudados na Reserva Florestal de Linhares (220 km2), que cornpreende 25 porcento da floresra Atlintica primlria remanescente do Esrado do Espirito Santo, Brasil. A andise de fezes indicou o consumo de 24 esptcies de presas (N = 101 arnosrras). Mamiferos representaram 87 porcento do total de itens, seguidos por rtpteis (9.8%) e aves (2.8%). Considerando o peso das presas 23.4 porcento dos itens pesavam entre 1 e 3 kg, 40.5 porcenro de 3 a 10 kg, e 27.7 porcento acima de 10 kg. De acordo com a análise de freqütncia relariva de ocorrsncia e a estimariva de biomassa relativa, a dieta concentra‐se em dois itens: o tatu galinha e queixada. A onga pintada parece basear sua dieta nas mesmas esptcies de mamiferos ao longo de sua distribuig8o geogrlfica.
Comparative Genetic Structure between Tropical Colombian and North American Drosophila pseudoobscura Populations1
Authors: Alvarez Diana , Noor Mohamed A. F. , Ruiz‐Garcia Manuel
Published: March 2006

Since the discovery of Drosophila pseudoobscura in the tropical highlands of the Colombian Andes during the 1960s, this population has been studied by many evolutionary biologists because of its geographical isolation from the main North American range of this species. We used five highly variable microsatellite loci (DPSX001, DPS2001, DPS3001, DPS3002, and DPS4001) to analyze the genetic structure of three Colombian populations and the genetic relationships with four North American populations. We found that the average heterozygosity was consistent among the three tropical Colombian populations (H = 0.665–0.675), but they had less variability than their North American counterparts. Nonetheless, the genie diversity found in the Colombian populations was higher than that found previously using other genetic markers. The average genie heterogeneity estimate among the Colombian populations (Rjr = 0.042), although statistically significant, was substantially lower than that found among the North American populations (RsT = 0.088). We identified alleles in the Colombian populations not reported in North American populations, suggesting further divergence between the populations. We estimated that the populations on the two continents diverged ca 80,000 years ago, consistent with independent sequence analyses of these populations but contrary to some suggestions in the literature. Finally, we estimated an average effective population size of the Colombian populations to be on the order of 100,000.
Home Range of Dobsonia minor (Pteropodidae): A Solitary, Foliage–roosting Fruit Bat in Papua New Guinea
Authors: Bonaccorso Frank J. , Winkelmann John R. , Dumont Elizabeth R. , Thibault Katherlne
Published: March 2006

Lesser bare–backed bats (Dobsonia minor [Pteropodidae]) are solitary and roost in foliage of understory and subcanopy trees in lowland rain forest. These 70–90 gram frugivorous bats forage in primary and secondary forest and in abandoned gardens. At the Kau Wildlife Area in Papua New Guinea, movements (N = 1041) of four males and four females fitted with radio transmitters were monitored for 1 to 18 months. Mean home range within 30–day sampling periods was 5.1 ha (N = 12). There were no significant differences in home ranges by sex or by dry–wet season. Females, however, had significandy larger mean core–use areas than males (1.43 ± 0.61 and 0.65 ±0.16 ha, respectively). There was moderate overlap in home range and core–use areas among some simultaneously tracked animals. The long axes of home ranges varied from 150 to 1150 m and the mean was significantly larger in females. Individuals commuted from day roosts to multiple feeding areas, sometimes resulting in disjunct core–use areas and home ranges. Fruits of native Fiats species and the exotic shrub Piper attuncum were staple food items. Piper aduncum grew as dense clusters within early successional habitats, and individual plants ripened 5–20 fruits per night throughout the year. Ficus spp. grew in primary and secondary forest and fruited asynchronously, but individual trees produced tens to thousands of ripe fruits over 7 to 10 days. Three adult female D. minor were tracked over multiple periods spanning 2.5–18 months. Although each female continued to visit a core–use area containing P. aduncum throughout the study, turnover of other core–use areas reflected the ephemeral locations of fruiting fig trees.
Organic Matter Dynamics on the Forest Floor of a Micronesian Mangrove Forest: An Investigation of Species Composition Shifts1
Authors: Gleason Sean M. , Ewel Katherine C.
Published: March 2006

Species composition shifts in mangrove forests may alter organic matter dynamics. The purpose of this study was to predict the effect of species replacements among mangrove trees on organic matter dynamics in a mangrove forest on the island of Kosrae, Federated States of Micronesia. We were particularly interested in elements of the carbon cycle that affect peat accumulation rates, organic matter exports to the estuary and coral reef systems, and soil microbiology. We compared organic matter production and decomposition rates among three mangrove species that commonly grow in similar hydrogeomorphic settings: Rhizophora apiculata BL, which is selectively harvested; Bruguiera gymnorrhiza, which may gradually replace Rhizophora; and Sonneratia alba, which is producing few mature fruits. Sonneratia had significantly higher rates of root production (estimated with ingrowth chambers) than Bruguiera or Rhizophora. Sonneratia foliage had significantly faster decomposition rates and significantly lower lignin:nitrogen ratios than Bruguiera foliage. Live root mass was positively correlated with ingrowth and soil carbon, although soil carbon and ingrowth were not significantly correlated with each other. Humic acid concentrations were significantly higher in Sonneratia rhizospheres than in either Bruguiera or Rhizophora rhizospheres and were positively correlated with root ingrowth. The species changes taking place on Kosrae are likely to result in lower rates of root production and foliage decomposition, and more refractory carbon pools in soil.
The Role of Cloud Combing and Shading by Isolated Trees in the Succession from Maquis to Rain Forest in New Caledonia1
Authors: Rigg L. S. , Enright N. J. , Perry G. L. W. , Miller B. P.
Published: March 2006

This study examined the role of shading and cloud combing of moisture by scattered trees of the emergent conifer Araucaria laubenfelsii (Corbass.) in montane shrubland‐maquis at Mont Do, New Caledonia, in facilitating the succession from shrubland to rain forest. Water collection experiments showed that these trees combed significant amounts of water from low clouds on days when no rainfall was recorded and deposited this moisture on the ground beneath the tree canopy. Analysis of photosystem II function in A. laubenfelsii and five other plant species using fluorometry revealed much lower photosystem stress in plants beneath scattered A. laubenfelsii than for individuals exposed to full sunlight in the open maquis. Transition matrix analyses of vegetation change based on “the most likely recruit to succeed” indicated that the transition from maquis to forest was markedly faster when emergent trees of A. laubenfelsii acted as nuclei for forest species invasion of die maquis. On the basis of these lines of evidence, it is argued that increased moisture and shading supplied to the area directly below the crown of isolated A. laubenfelsii trees in the maquis facilitates the establishment of both conifer seedlings and other rain forest tree and shrub species. In the absence of fire, rain forest can reestablish through spread in two ways: first, by expansion from remnant patches, and second, from coalescence of small rain forest patches formed around individual trees of A. laubenfelsii.
High Temperatures and Net CO2 Uptake, Growth, and Stem Damage for the Hemiepiphytic Cactus Hylocereus undatus1
Authors: Nobel Park S. , De la Barrera Erick
Published: March 2006

Hylocereus undatus, which is native to tropical forests experiencing moderate temperatures, would not be expected to tolerate the extremely high temperatures that can be tolerated by cacti native to deserts. Nevertheless, total daily net CO2 uptake by this hemiepiphytic cactus, which is widely cultivated for its fruits, was optimal at day/night air temperatures of 30/20°C, temperatures that are higher than those optimal for daily net CO2 uptake by cacti native to arid and semiarid areas. Exposure to 35/25°C for 30 weeks led to lower net CO2 uptake than at 10 weeks; exposure to 40/30°C led to considerable necrosis visible on the stems at 6 weeks and nearly complete browning of the stems by 19 weeks. Dry mass gain over 31 weeks was greatest for plants at 30/20°C, with root growth being especially noteworthy and root dry mass gain representing an increasing percentage of plant dry mass gain as day/night air temperatures were increased. Viability of chlorenchyma cells, assayed by the uptake of the vital stain neutral red into the central vacuoles, was decreased 50 percent by a one‐hour treatment at 55°C compared with an average of 64°C for 18 species of cacti native to deserts. The lower high‐temperature tolerance for H. undatus reflected its low high‐temperature acclimation of only 1.4°C as growth temperatures were raised by 10°C compared with an average acclimation of 5.3°C for the other 18 species of cacti. Thus, this tropical hemiepiphytic cactus is not adapted to day/night air temperatures above ca 40/30°C, although its net CO2 uptake is optimal at the relatively high day/night air temperatures of 30/20°C.
Disperser‐ vs. Establishment‐Limited Distribution of a Riparian Fig Tree (Ficus insipida) in a Costa Rican Tropical Rain Forest1
Authors: Banack Sandra Anne , Horn Michael H. , Gawlicka Anna
Published: March 2006

Studies were conducted at the La Selva Biological Station in Costa Rica and in a greenhouse in California to determine the factors accounting for the nonrandom distribution of the riparian fig tree Ficus insipida Willd. along streams in the La Selva Biological Reserve and adjacent deforested lands. We also evaluated the potential seed dispersers of this tree relative to the role of the fruit‐eating fish Brycon guatemalensis that previously was proposed to be an important disperser of F. insipida seeds in this system. At La Selva, we recorded the fig‐foraging activities of vertebrates at fruiting F. insipida trees, surveyed for the presence or absence of F. insipida along streams of different sizes, and determined the fate of fig seedlings transplanted in different riparian habitats. In the greenhouse, we measured seed germination and seedling survival and growth under different light and soil pH conditions mimicking natural conditions. The findings provided evidence that (1) the tree occurs along the larger streams running through forest habitat and only along smaller streams with relatively high light availability; (2) bats (Artibeus spp.) and fish are the major dispersers of F. insipida seeds; (3) the seedlings are subject to mortality not only from low light conditions but also from treefalls, frequent flooding, and bank erosion; and (4) high light levels and near neutral soil pH result in relatively better seed germination, faster growth, and higher survival rates of seedlings. Overall, our results suggest that this fig tree is dispersed mainly by bats and fish and is more establishment‐limited than disperser‐limited in its local distribution in the La Selva rain forest habitat.
Ornithophilous and Chiropterophilous Pollination in Musa itinerans (Musaceae), a Pioneer Species in Tropical Rain Forests of Yunnan, Southwestern China1
Authors: Liu Ai‐Zhong , Li De‐Zhu , Wang Hong , Kress W. John
Published: March 2006

The role of bats and sunbirds in the pollination ecology of Musa itinerans Cheesman (Musaceae) was studied in the tropical seasonal rain forests of Xishuangbanna, southern Yunnan, China. It was found that both long–tongued fruit bats (Macroglossus sobrinus) and sunbirds (Arachnothera longirostris) were effective pollinators of M. itinerans. Nectar production had two peaks, one during the day and one during night (0800–1200 h and 2000–2400 h), which allowed the two different foragers to visit at specific times. The visitation patterns of the two foragers coincided with both flowering time and nectar production. By measuring the differences in fruit weight and seed production among different bagging experiments, we found that birds and bats were equally effective as pollinators of this species.
Primary Seed Dispersal by Red Howler Monkeys and the Effect of Defecation Patterns on the Fate of Dispersed Seeds1
Authors: Andresen Ellen
Published: March 2006

The effectiveness of a seed disperser depends on the quantity and quality of dispersal. The quality of dispersal depends in large part on factors that affect the post–dispersal fate of seeds, and yet this aspect of dispersal quality is rarely assessed. In the particular case of seed dispersal through endozoochory, the defecation pattern produced has the potential of affecting the fate of dispersed seeds and consequently, dispersal quality and effectiveness. In this study, I assessed the effects of dung presence and dung/seed densities on seed predation by rodents and secondary dispersal by dung beetles. In particular, I compared seed fates in clumped defecation patterns, as those produced by howler monkeys, with seed fates in scattered defecation patterns, as those produced by other frugivores. I also determined the prevalence of red howler monkeys(Alouatta seniculus)as seed dispersers at the plant community level in Central Amazonia by determining the number of species they dispersed in a 25–month period. I found that dung presence and amount affected rodent and dung beetle behavior. Seed predation rates were higher when dung was present, and when it was in higher densities. The same number of seeds was buried by dung beedes, in dumped versus scattered defecation patterns, but more seeds were buried when they were inside large dung–piles versus small piles. Seed density had no effect on rodent or dung beetle behavior. Results indicate that caution should be taken when categorizing an animal as a high or low quality seed disperser before carefully examining the factors that affect the fate of dispersed seeds. Red howler monkeys dispersed the seeds of 137 species during the study period, which is the highest yet reported number for anAlouattaspecies, and should thus be considered highly prevalent seed dispersers at the plant community level in Central Amazonian terra firme rain forests.
Effects of Selective Logging on Populations of Two Tropical Understory Herbs in an Amazonian Forest1
Authors: Costa Flívia Regina Capellotto , Senna Cristina , Nakkazono Erika Matsuno
Published: March 2006

This study examined the effects of (1) rime elapsed after logging and (2) logging intensity on the total, juvenile, and adult densities, and on reproduction of Calathea altissima and Ischnosiphon amuma (Matantaceae), two monocot herb species in the understory of Central Amazonian forests. Logging was carried out experimentally at various intensities in eight plots (4 ha each) during 1987 and three plots in 1993. Five plots were left as experimental controls. In 1998, total and adult densities of the two species were greater in the plots logged 11 years before than in controls. For I. arouma, total and adult densities were also higher in the plots logged 5 years before; however, juvenile densities were less affected. The intensity of logging influenced adult density of both species but not total or juvenile densities. Densities of reproductive individuals of both species were higher in the logged areas and increased with logging intensity. The effects of time after logging and logging intensity on reproduction were indirect due to the greater number of adult plants in those areas. The observed effects were probably mediated by changes in canopy cover in logged areas. Greater light intensities in logging gaps, roads, and their margins may lead to increased reproduction, recruitment, growth, and survival, which in turn can lead to increased plant density. These results indicate that logging has long–term effects on understory plant populations.