bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use‐history Effects on Structure and Flora of Caatinga
Authors: Pereira Israel M. , Andrade Leonaldo A. , Sampaio Everardo V. S. B. , Barbosa Maria Regina V. 
Published: March 2006

ABSTRACTFloristic composition and vegetation structure of plants 3 cm stem diameter or greater were compared at four sites in the Agreste of Paraiba, Brazil: (1) little disturbed for five decades (LD); (2) grazed fragment, selectively logged 16 years before sampling (GF); (3) naturally regrowing for 30 years after 39 years of agriculture (OR); and (4) naturally regrowing for 20 years after 35 years of agriculture plus 15 years of pasture (NR). Cattle graze frequently in the last three sites but very seldom in LD. The little disturbed site had more species (53) than the other three sites (36, 25, and 11 species in GF, OG, and NG, respectively) and also more (3253, 2780, 2780, and 2115 plants/ha) and larger plants (34.8, 26.8, 18.6, and 7.8 m2/ha), including taller tree species (up to 15 m) absent in the other sites (maximum height: 14, 6, and 5 m). Differences were striking in relation to NR, the site with longer use and shorter regrowth period, which was strongly dominated by only two species: Mimosa tenuiflora (73% relative density and 81% basal area) and Piptadenia stipulacea (21% relative density and 16% basal area). These results indicate that abandoned agricultural sites may take several decades to reestablish vegetation similar to die original.RESUMOForam comparadas a composição florística e a estrutura da vegetação das plantas com dia̧metro do caule S 3 cm, em quatro áreas no Agreste da Paraíba: (1) pouco perturbada por cinco décadas (LD); (2) fragmento pastejado que teve corte seletivo de árvores 16 anos antes da amostragem (GF); (3) revegetação natural por 30 anos depois de 39 anos de agricultura (OR); e (4) revegetação natural por 20 anos depois de 35 anos de agricultura e 15 anos como pasto plantado (NR). Gado bovino pasta frequentemente nas trȩs últimas áreas e só raramente em LD. A área pouco perturbada tinha maior número de espécies (53) que as outras trés áreas (36, 25 e 11 espécies em GF, OR e NR, respectivamente), além de plantas em maior número (3253, 2780, 2780 e 2115 plantas/ha) e de maior tamanho (34.8, 26.8, 18.6 e 7.8 m2/ha), incluindo espécies arbóreas mais alias (até 15 m), ausentes nas outras áreas (alturas máximas de 14, 6 e 5 m). As diferenças foram marcantes em relação a NR, área com maior tempo de uso e menor tempo de revegetação, e dominada por apenas duas espécies: Mimosa tenuiflora (densidade e área basal relativas de 73 e 81%) e Piptadenia stipulacea (21% de densidade e 16% de área basal). Os resultados indicam que as áreas de agricultura abandonadas podem levar décadas até estabelecerem vegetação semelhante á original.
Foraging Patterns of Sympatric Hornbills during the Nonbreeding Season in Arunachal Pradesh, Northeast India
Authors: Datta Aparajita , Rawat G. S. 
Published: March 2006

ABSTRACTThe diet and food resource partitioning of three sympatric hornbills (Great Hornbill Buceros bicornis, Wreathed Hornbill Aceros undulatus, and Oriental Pied Hornbill Anthracoceros albirostris) during the nonbreeding season were studied relative to fruit availability in a foothill semievergreen forest of Arunachal Pradesh, northeast India. Hornbills fed on fruits of 49 plant species that comprised over 95 percent of their diet. Hornbill species partitioned food resources by varying the relative contribution of figs and non‐fig fruits in the diet. Similarity in non‐fig fruit diet was low. Ten species contributed to over 90 percent of the non‐fig diet. The availability of non‐fig fruits was much lower in the nonbreeding season than in the breeding season; however, despite lower fruit availability during the nonbreeding season, hornbills had a wide diet breadth and indirect evidence suggests that Wreathed Hornbills foraged widely in this season for fruit. Great Hornbills relied more on figs that were available year‐round. The diverse diet breadth that included rare and patchy fruit resources underscores the importance of conserving large forest tracts for hornbills.
Contrasting Responses to Induction Cues by Ants Inhabiting Maieta guianensis (Melastomataceae)
Authors: Lapola David M. , Bruna Emilio M. , Vasconcelos Heraldo L. 
Published: March 2006

ABSTRACTThe two most common ant associates of the understory myrmecophyte Maieta guianensis (Melastomataceae) respond in different ways to experimental cues associated with herbivory. While Pheidole minutula is induced by both physical damage and extracts of leaf tissue, Crematogaster laevis is induced by leaf damage only. We suggest such interspecific variation in induced responses is common and could influence the quality of defense against herbivores provided to host‐plants by ants.RESUMOAs duas formigas que mais comumente se associam com a mirmecófita de sub‐bosque Maieta guianensis (Melastomataceae) respondem de maneiras diferentes a simulações experimentais de herbivoria. Enquanto Pheidole minutulaé induzida tanto por danos fisicos e extratos de tecido foliar, Crematogaster laevisé induzida apenas pelos danos fisicos. Sugerimos que tal variação interespecifica em respostas induzidas é comum e pode influenciar a qualidade das defesas contra herbívoros que as formigas oferecem às plantas que elas ocupam.
Root/Shoot Allocation and Root Architecture in Seedlings: Variation among Forest Sites, Microhabitats, and Ecological Groups1
Authors: Paz Horacio 
Published: March 2006

ABSTRACTI analyzed patterns of variation in root mass allocation and root morphology among seedlings of woody species in relation to environmental factors in four Neotropical forests. Among forests, I explored the response of root traits to sites varying in water or nutrient availability. Within each forest, I explored the plastic response of species to different microhabitats: gaps and understory. Additionally, I explored evidence for life history correlation of root and shoot traits by comparing species differing in their successional group (light‐demanding [22 spp.] or shade tolerant [27 spp.]) and germination type (species with photosynthetic cotyledons or species with reserve cotyledons). At each forest site, young seedlings from 10 to 20 species were excavated. A total of 55 species was collected in understory conditions and 31 of them were also collected in gaps. From each seedling, six morphological ratios were determined. Allocation to roots was higher in forest sites with the lowest soil resources. Roots were finer and longer in the most infertile site, while roots were deeper in the site with the longest dry season. Seedling traits did not differ between germination types. Shade tolerant species allocated more to roots and developed thicker roots than light‐demanding species. Light‐demanding species showed stronger plastic responses to habitat than shade tolerant species, and species with photo‐synthetic cotyledons showed lower plasticity than species with reserve cotyledons. Overall, these results suggest that among Neotropical species, root allocation and root morphology of seedlings reflect plant adjustments to water or nutrient availability at geographic and microhabitat scales. In addition, life history specialization to light environments is suggested by differences among groups of species in their allocation to roots and in their root morphology.
Genetic Evidence for Natural Hybridization between Species of Dioecious Ficus on Island Populations1
Authors: Parrish Tracey L. , Koelewijn Hans P. , van Dijk Peter J. , Kruijt Marco 
Published: March 2006

ABSTRACTNatural hybrids between Ficus septica and two closely related dioecious species, F. fistulosa and F. hispida, were confirmed using amplified fragment length polymorphisms (AFLP) and chloroplast DNA markers. Ficus species have a highly species‐specific pollination mutualism with agaonid wasps. Therefore, the identification of cases in which breakdown in this sophisticated system occurs and the circumstances under which it happens is of interest. Various studies have confirmed that Ficus species are able to hybridize and that pollinator‐specificity breakdown can occur under certain conditions. This study is the first example in which hybrid identity and the presence of hybrids in the natural distribution of parental species for Ficus have been confirmed with molecular markers. Hybrid individuals were identified on three island locations in the Sunda Strait region of Indonesia. These findings support Janzen's (1979) hypothesis that breakdown in pollinator specificity is more likely to occur on islands. We hypothesized that hybrid events could occur when the population size of pollinator wasps was small or had been small in one of the parental species. Later generation hybrids were identified, indicating that backcrossing and introgression did occur to some extent and that therefore, hybrids could be fertile. The small number of hybrids found indicated that there was little effect of hybridization on parental species integrity over the study area. Although hybrid individuals were not common, their presence at multiple sites indicated that the hybridization events reported here were not isolated incidences. Chloroplast DNA haplotypes of hybrids were not derived solely from one species, suggesting that the seed donor was not of the same parental species in all hybridization events.
Does Müllerian Mimicry Work in Nature? Experiments with Butterflies and Birds (Tyrannidae)1
Authors: Pinheiro Carlos E. G. 
Published: March 2006

ABSTRACTThe selective advantage of Müllerian mimicry in nature was investigated by releasing live mimetic and nonmimetic butterflies close to wild, aerial‐hunting tropical kingbirds (Tyrannus melancholicus) and cliff‐flycatchers (Hirundinea ferruginea) in three Amazon habitats (rain forest, a city, and “canga” vegetation). Only mimetic butterflies elicited sight‐rejections by birds, but protection conferred by mimicry was restricted to sites in which both predators and mimics co‐occurred, as in the case of six mimicry rings at a forest site and two at a city site. Most other Müllerian mimics released at city and canga vegetation were heavily attacked and consumed by birds. These results appear to reflect the birds’previous experiences with resident butterfly faunas and illustrate how birds’discriminatory behavior varied among habitats that differed in butterfly species and mimicry ring composition.
Fragmentation and Alteration of Seed Dispersal Processes: An Initial Evaluation of Dung Beetles, Seed Fate, and Seedling Diversity1
Authors: Chapman Colin A. , Chapman Lauren J. , Vulinec Kevina , Zanne Amy , Lawes Michael J. 
Published: March 2006

ABSTRACTGiven current accelerated trends of tropical land conversion, forest fragments are being incorporated into many conservation programs. For investing in fragments to be a viable conservation strategy, forest fragments must maintain their ecological integrity over the long term. Based on fieldwork in 22 forest fragments in the crater lakes region of western Uganda and in the continuous forest of Kibale National Park, we examined (1) seed predation on experimentally dispersed seeds, (2) abundance and composition of the dung beetle community that may play a major role in removing seeds from sites of high seed predation, and (3) compared the fragments’ seedling community composition to adult tree community composition and the seedling community in continuous forest. First, the rate of seed removal at experimental stations was lower in forest fragments (85% remaining after 1 day) than at stations in the continuous forest (79% remaining) and the probability of stations being discovered by seed predators was lower in fragments (23%) than in the intact forest (41%). Second, there was a 62 percent decline in fragment dung beetle abundance. The magnitude of this decline varied among dung beetle guilds that process dung and seeds in different fashions. The abundance of large rollers that move large seeds away from sites of defecation did not differ, but medium and smaller rollers and burying beetles that process small and medium‐sized seeds were less common in the fragments than in the intact forest. Finally, we compared the seedling community composition relative to adult tree community composition by identifying all adult trees in each fragment and by sampling the composition of the seedling community. We found some evidence to suggest that there was movement of seeds among forest fragments by large‐bodied dispersers, particularly chimpanzees (Pan troglodytes) and hornbills (Ceratogymna subcylindricus).
Rapid Turnover and Edge Effects in Dung Beetle Assemblages (Scarabaeidae) at a Bolivian Neotropical Forest‐Savanna Ecotone1
Authors: Spector Sacha , Ayzama Sergio 
Published: March 2006

ABSTRACTHabitat fragmentation and the widespread creation of habitat edges have recently stimulated interest in assessing the effects of ecotones on biodiversity. Ecotones, natural or anthropogenic, can greatly affect faunal movement, population dynamics, species interactions, and community structure. Few data exist, however, on insect community response to forest–savanna ecotones, a natural analog to anthropogenically cleared areas adjacent to forest. In this study, the abundance, total biomass, average individual biomass, and distribution of scarabaeine dung beetles were examined at a sharp tropical evergreen forest–savanna ecotone in Santa Cruz, Bolivia. The abundance, total biomass, and average individual biomass of dung beetles varied significantly across the forest, edge, and savanna habitats. Species richness (Sobs) also varied significantly across the three habitats, but statistical estimations of true species richness (Sest) did not. Habitat specificity of the dung beetles in this study was extremely high. Of the 50 most common species collected during the study, only 2 species were collected in both the forest and savanna habitats, signaling nearly complete community turnover in just a few meters. Strong edge effects were evidenced by the decline in abundance, total biomass, and species richness at the forest‐savanna boundary.
Roosting Requirements of Two Frugivorous Bats (Sturnira lilium and Arbiteus intermedius) in Fragmented Neotropical Forest1
Authors: Evelyn Michelle J. , Stiles David A. 
Published: March 2006

ABSTRACTAs tropical forest fragmentation accelerates, scientists are concerned with the loss of species, particularly those that play important ecological roles. Because bats play a vital role as the primary seed dispersers in cleared areas, maintaining healthy bat populations is critical to natural forest regeneration. Observations of foraging bats suggest that many Neotropical fruit‐eating species have fairly general habitat requirements and can forage in many different kinds of disturbed vegetation; however, their roosting requirements may be quite different. To test whether or not general foraging requirements are matched by equally broad roosting requirements, we used radiotelemetry to locate roost sites of two common frugivorous bat species (Sturnira lilium and Artibeus intermedius) in a fragmented forest in southeastern Mexico. Sturnira lilium roosted inside tree cavities and selected large‐diameter roost trees in remnant patches of mature forest. Fewer than 2 percent of trees surveyed had a mean diameter equal to or greater than roost trees used by . S. lilium, Artibeus intermedius roosted externally on branches and vines and under palm leaves and selected roost trees of much smaller diameter. Compared to random trees, roost trees chosen by A. intermedius were closer to neighboring taller trees and also closer in height to these trees. Such trees likely provide cryptic roosts beneath multiple overlapping crowns, with sufficient shelter from predators and the elements. While males of A. intermedius generally roosted alone in small trees within secondary forest, females roosted in small groups in larger trees within mature forest and commuted more than three times farther than males to reach their roost sites. Loss of mature forest could impair the ability of frugivorous bats to locate suitable roost sites. This could have a negative impact on bat populations, which in turn could decrease forest regeneration in impacted areas.
Species‐specific Seedling Responses to Hurricane Disturbance in a Puerto Rican Rain Forest1
Authors: Walker Lawrence R. , Lodge D. Jean , Guzmín‐Grajales Sandra M. , Fetcher Ned 
Published: March 2006

ABSTRACTSeedling dynamics were followed in a Puerto Rican forest for 20 months following a severe hurricane to study the interactive effects of hurricane debris, nutrients, and light on seedling diversity, density, growth, and mortality. Three treatments (debris removal, an unaltered control with hurricane debris, and chemical fertilization added to hurricane debris) altered levels of forest debris and soil nutrients. Canopy openness was measured twice using hemispherical photographs of the canopy. We examined the demographic responses of six common species to treatments over time. Seedling densities increased for all six species but the only significant treatment effects were increased densities of the pioneer treeCecropiaand the shrubPalicoureain the debris removal treatment. Seedling growth declined with declining light levels for four species but not for the pioneer treeAlchorneaor the non‐pioneer treeDacryodes.OnlyCecropiaand the non‐pioneer treeChionanthushad treatment effects on growth. Mortality also differed among species and tended to be highest in the fertilized plots for all butCecropiaandDacryodes.We found only some of the expected differences between pioneer and non‐pioneer plants, as each species had a unique response to the patchy distributions of organic debris, nutrients, and light following the hurricane. High local species diversity was maintained through the individualistic responses of seedlings after a disturbance.
Fruit Bats (Chiroptera: Pteropodidae) as Seed Dispersers and Pollinators in a Lowland Malaysian Rain Forest1
Authors: Hodgkison Robert , Balding Sharon T. , Zubaid Akbar , Kunz Thomas H. 
Published: March 2006

ABSTRACTThe aims of this study were to (1) characterize the food resources exploited by fruit bats (Pteropodidae) within an old‐growth Malaysian dipterocarp forest, (2) test the viability of the seeds they disperse, and (3) provide an estimate of the proportion of trees that are to some degree dependent upon bats for seed dispersal and/or pollination. Fruit species exploited by bats could be distinguished from those eaten by birds largely on the basis of color (as perceived by human beings). Bat‐dispersed fruits were typically inconspicuous shades of green–yellow or dull red–brown, whereas fruits eaten by birds were generally bright orange to red. Dietary overlap between bats and nonflying mammals was relatively high. In contrast to primates and squirrels, which were major seed predators for several of the plant species under investigation, fruit bats had no negative impact on seed viability. A botanical survey in 1 ha of old‐growth forest revealed that 13.7 percent of trees (≫15 cm girth at breast height) were at least partially dependent upon fruit bats for pollination and/or seed dispersal.
Capture Rates of Male Euglossine Bees across a Human Intervention Gradient, Chocó Region, Colombia1
Authors: Otero J. Tupac , Sandino Juan Carlos 
Published: March 2006

ABSTRACTEuglossine bees are important pollinators of lowland Neotropical forests. Compared to disturbed habitats, undisturbed ones have been previously characterized by higher abundance and diversity of euglossine bees. Most past studies have relied on chemically baiting male bees at single sites within habitats. Over a two‐year period, we employed a repeated‐measures design in which we sampled bees at multiple sites within three different habitat types, reflecting a mosaic of human disturbance (farm, secondary forest, and old logged forest). After 22 monthly samples, a total of 2008 male bees were captured, representing 31 species in five genera: 1156 at the farm (57.6%, 21 spp.), 505 in the secondary forest (25.1%, 27 spp.), and 347 in the old logged forest (17.2%, 21 spp.). Eighty‐one percent of the bees captured belonged to the five most abundant species: Eulaema cingulata, El. chocoana, Euglossa hansoni, Eg. ignita, and Eg. imperialis. These species differed significantly in capture frequencies among habitats. Eulaema cingulata, El. chocoana, and Eg. ignita were captured most frequently at the farm, while Eg. imperialis was most abundant in the secondary forest. In contrast, Eg. hansoni, the sole short‐tongued species among the five, was equally abundant in the two forest habitats but occurred rarely on the farm. Additionally, habitats differed in bee composition. The high capture rates for long‐proboscis species at the farm may have been due to their ability to extract nectar from flowers with long floral tubes, which probably occurred at a greater density on the farmed land than in the adjacent forests.
Influence of Edge Exposure on Tree Seedling Species Recruitment in Tropical Rain Forest Fragments1
Authors: Benitez‐Malvido Julieta , Martínez‐Ramos Miguel 
Published: March 2006

ABSTRACTEdge creation has a pronounced influence on the understory vegetation, but the effects of edges on seedling species recruitment are still poorly understood. In Central Amazonia, 9–19 years after fragmentation, we recorded species richness and net seedling recruitment rate in 1 ha blocks exposed to none, one, or multiple edges within forest fragments. One‐hectare blocks were located in the center (no edge), the edge (one edge), the corners (two edges) of 10 and 100 ha fragments, and in a 1 ha fragment (four edges). In 1991, we counted all tree seedlings 5–100 cm tall found within permanent 1 m2 plots located within the 1 ha blocks. In May 1993, we manually removed all seedlings that were smaller than 1 m tall from the permanent plots. Six years and five months later (October 1999), all new seedlings recruited into the plots were counted and classified into distinct morphospecies. Species richness of recruited seedlings, scaled by total seedling density, declined from the center to the edge, the corner blocks, and then to the 1 ha fragment. Overall, the four‐edged, 1 ha fragment had the poorest species richness and the non‐edged 100 ha central block the highest. The total number of recruited individuals was 40 percent less than that previously present, with the 100 ha corner having the lowest recruitment. Pairwise comparisons showed that species similarity was related to edge number for the 100 and 1 ha fragments. Species rank/abundance curves showed that a subset of species was common in all blocks within the fragments, and that the 100 ha center held more rare species than any other 1 ha block. This study demonstrated that, in a given fragment patch, the number of tree seedling species recruited varied inversely with the number of edges.
Effects of Species, Density, Patch‐type, and Season on Post‐dispersal Seed Predation in a Puerto Rican Pasture1
Authors: Myster Randall W. 
Published: March 2006

ABSTRACTAn experimental study of seed removal of four woody species in an abandoned pasture revealed significant main effects of species, density (higher densities survived more than lower densities), and patch‐type (seeds under shrub patches survived more than in grass patches), but no effects of season. Rates of seed loss decreased with seed size across species. Significant interactions between species and density and between species and patch‐type were also observed.
Expedition to Kubunitu1
Authors: Whitmore T. C. 
Published: March 2006

ABSTRACTThis is a personal account of a 1964 expedition in search of two conifer species on Mts. Sasari and Kubunitu, the two highest peaks on Santa Ysabel in the Solomon Islands. Dacrydium xanthandrum and Dillenia crenata were both discovered in flower and collections were made. The account was recently discovered in Tim Whitmore's files.