bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollination Biology of Myrrhinium atropurpureum (Myrtaceae): Sweet, Fleshy Petals Attract Frugivorous Birds
Authors: Roitman G. Germán , Montaldo Norberto H. , Medan Diego 
Published: March 2006

ABSTRACT Myrrhinium atropurpureum has unusual floral characteristics: sweet, juicy petals, long vivid stamens, and absence of nectar and odor. This uncommon syndrome is morphologically and anatomically described. Floral phenology is also described, and censuses of flower visitors are provided. The main pollinators are frugivorous passerine birds, which are attracted by the petals. This type of floral reward is vev uncommon and seems to be restricted, in South America, to Myrrhinium, Feijoa (Myrtaceae) and Calceolaria (Scrophulariaceae). The possible origin of the pollination mechanism is discussed.RESUMEN Myrrhinium atropurpureum posee caracteres florales inusuales: pétalos dulces y carnosos, estambres exertos y vistosos, y ausencia de néctar y perfume. Este poco común síndrome floral es descrito morfológica y anatómicamente. Se describe la fenología floral y se censaron los visitantes a las flores. Los principales polinizadores son aves frugívoras, que son atraídas por los pétalos. Este tipo de recompensa floral es infrecuente y parece estar restringido, en Sudamérica, a Myrrhinium, Feijoa (Myrtaceae) y Calceolaria (Scrophulariaceae). Se discute el posible origen de este mecanismo de polinización.
Differential Flower Herbivory and Gall Formation on Males and Females of Neea psychotrioides, a Dioecious Tree
Authors: Wolfe Lorne M. 
Published: March 2006

ABSTRACTThe goal of this study was to determine whether there exists intersexual differences in the degree of herbivore attack on a tropical, dioecious tree. Neea pychotrioides is a Costa Rican tree that experiences at least two types of attack on its reproductive structures: flower herbivory and gall formation on inflorescences. Although female trees were more common than males in the two study populations (overall sex ratio = 1.5 females/male), male flowers were more likely to be eaten by lepidopteran larvae. Similarly, inflorescence‐borne, fly‐induced galls were more frequent on males. Ten families of insects from three orders (Diptera, Hymenoptera, Lepidoptera) occupied the galls with varying levels of parasitism and hyperparasitism occurring within. Although the sexes were not significantly different in vegetative size, males had larger floral displays (more inflorescences and larger flowers) that may have acted as attractants to herbivores and gallmakers. The results are consistent with the hypothesis that flower damage and the energetic costs of producing galls exert a greater expense to males, ultimately resulting in death, and over time, a skewing of the sex ratio.
The Diet and Reproductive Schedules of Leptonycteris curasoae curasoae and Glossophaga longirostris elongata (Chiroptera: Glossophaginae) on Curaçao
Authors: Petit Sophie 
Published: March 2006

ABSTRACTTwo bat species, Leptonyrteris curasoae and Glossophaga longirostris, are the principal pollinators of at least two of the three species of columnar cacti that grow on the semiarid island of Curaçao, Netherlands Antilles. I examined the importance of the cacti in the diets of the bats and found that 85–91 percent of their diet samples contained cactus pollen and seeds. At least 43 percent of the samples from each species contained cactus pollen andlor seeds exclusively. Leptonycteris curasoae consumes nectar and pollen of Ceiba pentandra and Agave spp. at the beginning of the dry season and G. longirostris also consumes a few other plant products in the wet season, but both bat species depend nutritionally on cacti. Female bats give birth to one pup per year, and the periods of parturition and lactation in each species correspond to peaks in the reproductive phenology of the two most abundant columnar cactus species. From personal observations and a review of the literature, I determined that bats were unlikely to fly to the mainland to feed, although L. curasoae may do so. I conclude that the interdependence of bats and cacti is suggestive of coevolution, and that columnar cacti are critical for the survival and persistence of nectar‐feeding bats on Curaçao.
Forest Regeneration in Logged and Unlogged Forests of Kibale National Park, Uganda
Authors: Chapman Colin A. , Chapman Lauren J. 
Published: March 2006

ABSTRACTProcesses of forest regeneration in two unlogged areas and in three areas that were logged nearly 25 years ago were quantified in Kibale National Park, Uganda. For forests to recover from logging, one would predict recruitment and growth processes to be accelerated in logged areas relative to unlogged areas, facilitating increased recruitment of trees into the adult size classes. We examined this prediction first by determining the growth of 4733 trees over a 51 to 56 month period and found that growth rates in the most heavily logged area were consistently slower than in the two unlogged areas. In contrast, the lightly logged forest had similar growth rates to unlogged areas in the small size classes, but trees in the 30 to 50 cm DBH size cohort exhibited elevated growth rates relative to the unlogged areas. Mortality was highest in the heavily logged areas, with many deaths occurring when healthy trees were knocked over by neighboring treefalls. We found no difference in the density or species richness of seedlings in the logged and unlogged forests. The number of seedlings that emerged from the disturbed soil (seed bank+seed rain) and initially seed‐free soil (seed rain) was greater in the logged forest than in the unlogged forest. However, sapling density was lower in the heavily logged areas, suggesting that there is a high level of seedling mortality in logged areas. We suggest that the level of canopy opening created during logging, the lack of aggressive colonizing tree species, elephant activity that is concentrated in logged areas, and an aggressive herb community, all combine to delay vegetation recovery in Kibale Forest.
Rhizophora mangle L. Seedling Development into the Sapling Stage across Resource and Stress Gradients in Subtropical Florida1
Authors: Koch Marguerite S. 
Published: March 2006

ABSTRACTNutrient, light, salinity, soil redox potentials, and other soil characteristics were determined across a range of mangrove forest heights across the South Florida peninsula encompassing large‐stature trees (> 10 m) on the west coast and dwarf forms (< 1 m) in the southeast Everglades. Relationships were established between abiotic factors and Rhizophora mangle seedling growth rates in four height (cm) classes, 25‐40, > 40‐55, > 55–70, and > 70–85. Light in open canopy gaps was an important determinant of seedling growth. Growth rates in gaps (0.32 ± 0.04 to 1.89 ± 0.18 mm/d) were two‐ to five‐fold greater than adjacent closed canopy forests (0.14 ± 0.01 to 0.40 ± 0.07 mm/d). Among open canopy sites, labile soil phosphorus and soil redox potentials were significantly correlated to growth (P < 0.05; r= 0.98 and 0.89, respectively). Interstitial salinity ranged from 0 to 27 ppt across sites, well below hypersaline conditions. Thus, under low salinity stress and high light availabiliry, soil fertility is proposed to be the dominant factor controlling R. mangle seedling development to a sapling stage (> 85 cm) in South Florida mangrove forests. In addition, soil anoxia is hypothesized to be an important stressor in lagoonal‐bay estuaries and marsh‐mangrove ecotones with minimal tidal exchange.
Observations at a Ficus Tree in Malagasy Humid Forest1
Authors: Goodman Steven M. , Ganzhorn Jörg U. , Wilmé Lucienne 
Published: March 2006

ABSTRACTAlthough several authors have recognized that Madagascar has a depauperate frugivore community, little quantitative data is available on this issue. In order to start filling this gap, systematic observations were made at a Ficus tree in the eastern humid forest. Information is presented on the vertebrate species that visited the tree, estimates of total fruit production and proportion consumed by frugivores, and the chemical analysis of the fruits.RÉSUMÉBien que de nombreux auteurs aient reconnu la faible importance des communautés frugivores de Madagascar, peu de données quantitatives sont actuellement disponibles sur cet aspect. Afin de pallier à ce manque, des observations systématiques ont été faites sur un Ficus dans la forêt humide de l'est. Les connaissances apportées concernent les espèces de vertébrés qui ont visité l'arbre, des estimations de la production totale de fruits, des proportions consommés par les frugivores, et des analyses chimiques des fruits.
Seasonal and Spatial Patterns in Ground Foraging Ants in a Rain Forest in the Western Ghats, India1
Authors: Basu Parthiba 
Published: March 2006

ABSTRACTSeasonal variation and spatial distribution in ground foraging rain forest ants were studied in South Kannada–Kodagu District in Karnataka (India) between 1990 and 1991 by pit‐fall trap sampling. All ant species showed marked seasonality. A total of 31 species were recorded from the primary forest over a period of two years. More species were recorded from the closed canopy forest than from tree fall gaps in primary forest. All ant species showed marked seasonality with fewer species and individuals sampled/plot during the wetter seasons. The numerically dominant species, Pheidole sp., was markedly lower in abundance during the wet seasons. Spatial patterns were also studied during a dry season both in the primary forest and an adjacent logged forest. More species were recorded from the logged forest than the primary forest. Community composition in primary forest was different from that in logged forest. Common species were more ubiquitous than rarer species. Species were distributed bimodally across sampling plots. Probable underlying processes behind these seasonal and spatial patterns have been discussed.
Isozyme Variation in a Tropical Pioneer Tree Species (Cecropia obtusifolia, Moraceae) with High Contents of Secondary Compounds1
Authors: Garay‐Arroyo Adriana , Alvarer‐Buylla Elena R. 
Published: March 2006

ABSTRACTWe define 48 allozyme loci for a tropical pioneer tree species, Cecropia obtusifolia Bertol, which has high contents of secondary compounds. Our goals were to find the effects of extraction procedures on artifacts and variation in resolution of enzyme banding patterns; to explore the relationship among the variation of the loci sampled and the enzymes' molecular structure, metabolic function and substrate; to obtain estimates of the genetic variation in this species at Los Tuxtlas rain forest (México) and to explore the variation of allelic frequencies in six successive life‐history stages of the species.The resolution of the isozymes bands and the actual banding pattern varied with the type and age of tissue, the collection and storage procedures, the extraction buffer, and other loading and running procedural details. However, artifactual variation was eliminated with a new extraction buffer for species with high contents of secondary compounds.Of the 26 enzymes resolved for C. obtusifolia, we found that enzymes with a greater number of substrates and an oligomeric quaternary structure tended to be more variable than their counterparts, but the relationship was not statistically significant. The proportion of polymorphic systems varied significantly with the metabolic pathway and the function of the enzymes. Enzymes involved in starch synthesis are significantly more variable (p < 0.05) than all others, except those involved in amino acids metabolism and the proportion of polymorphic enzymes is also significantly associated with the hnction of the enzyme, the hydrolases and isomerases are significantly more variable than lyases and oxidoreductases enzymes.The percentage of polymorphic loci for C. obtusifolia was estimated at P = 27.1%. The effective number of alleles was estimated at ne = 1.3 and ne = 2.4 for all loci and only polymorphic ones respectively and the average heterozygosity (H) for all 48 loci was estimated at H = 0.05. Allele frequencies varied throughout the life‐cycle of the species, with significant differences for some alleles and loci among some life‐cycle stages. “Tree seeds” allele frequencies differ significantly (P < 0.05) from “rainy dispersed seeds” in 7 of 8 loci and from “soil seeds” in Six of eight loci. Allele frequencies of all three seed categories (“tree seeds”, “rainy dispersed seeds”, and “soil seeds”) differed strongly from established individuals (seedlings, juveniles and adults), while allele frequencies of established individuals are relatively similar to one another. Seedling allele frequencies at most loci were also significantly different from those found in seeds collected from trees, seed‐rain, and soil. Two alleles (at GOT‐2 and FE‐2) were only found in soil seeds and one allele (at LAP‐2) was only found in seedlings.
Disturbance and Seasonal Dynamics of Mycorrhizae in a Tropical Deciduous Forest in Mexico1
Authors: Allen Edith B. , Rincón Emmanuel , Allen Michael F. , Pérez‐Jimenez Alfredo , Huante Pilar 
Published: March 2006

ABSTRACTMycorrhizal fungi were sampled in a deciduous tropical forest on the Pacific coast of Mexico during different seasons and in natural treefall gaps and pastures. All 12 plant species sampled in the forest were arbuscular mycorrhizal. The percent root infection and spore production were closely related to the phenology of the plants. Most tree species and all herbaceous species had the highest infection in the summer rainy season, but two species, Opuntia excelsa and Jacquinia pungens, had highest infection in the dry season. Unusually high rainfall during the dry season was associated with increased infection but not increased spore production. Spore density was low for all species at all sample times, except at the beginning of the July 1993 rainy season in, when we observed up to 28 spores/g soil.The percent cover of shrubs or herbs did not increase in gaps after two years, and we observed no colonizing seedlings. No plant species with cover higher than 2.7 percent occurred exclusively in gaps or forest. The percent mycorrhizal infection did not differ significantly between gaps and forest. Spore counts were as high in the gaps as in the forest in two of the three gaps but lower in the third gap. The lack of significant response of plants in these gaps after two years differed from the rapid response in tropical rainforests. It is likely related to the small size of the gaps and to light infiltration to the forest floor. Pastures were dominated by two species of exotic grasses and one species of mycorrhizal fungus, whereas forests had 15 fungal species. The slow regrowth of vegetation in gaps was not limited by mycorrhizal fungi, since they were still abundant after the treefalls, but recovery in pastures could be affected by low fungal diversity and dominance of grasses.
Microclimate Change and Effect on Fire Following Forest‐Grass Conversion in Seasonally Dry Tropical Woodland1
Authors: Freifelder Rachel R. , Vitousek Peter M. , D'Antonio Carla M. 
Published: March 2006

ABSTRACTWe tested the hypothesis that, where fire has historically been infrequent, wooded areas that have been invaded by grasses and converted to grassland by fire are predisposed to future fire compared to adjacent areas that remain wooded; thus, an initial forest fire may promote future fires. We compared microclimate between a grass‐dominated burned area and a nearby grass‐invaded woodland that has not burned in recent history, both located in the submontane dry forest of Hawaii Volcanoes National Park. The results were used to parameterize BEHAVE, a fire behavior prediction model developed by the USDA Forest Service. The model's predictions include probability of ignition, intensity, rate of spread, and tree mortality. Contrary to expectations, daytime hourly mean temperatures were higher and relative humidity was lower in the woodland site. However, the differences in temperature and humidity were not great enough to affect spread rate or probability of ignition. Wind speeds were substantially greater in the grassland, and this was most important in driving differences in modeled fire spread. Given similar synoptic conditions, a fire started in the grassland can be expected to spread an order of magnitude faster than one started in the woodland.
Tree Regeneration and Species Diversity Following Conventional and Uniform Spacing Methods of Selective Cutting in a Subtropical Humid Forest Reserve1
Authors: Montagnini Florencla , Eibl Beatriz , Szczipanski Lilian , Rios Romàn 
Published: March 2006

ABSTRACTThere are a variety of ways to diminish the negative impacts of forest management for timber on biodiversity. A pilot project using a uniform spacing method of selective cutting was recently implemented in the 5340 ha Guarani Reserve, Misiones, Argentina, to design adequate management schemes for the subtropical forests of the region. Uniform spacing involves moderate timber harvesting and careful selection of remnant trees. In this article we compare tree regeneration in forests experimentally cut by diameter limit and uniform spacing methods. Seedlings of five size classes from 10 cm to 3 m in height were sampled using rectangular nested plots. Three years after cutting, an average of 54,330 and 22,270 seedling/ha (all height classes combined) of commercial and non‐commercial species were found in the forest cut by uniform spacing and by minimum diameter, respectively. In an adjacent uncut forest there were 34,900 seedlings/ha, and in another forest cut by minimum diameters 30 years ago there were 50,000 seedlings/ha, The forest cut by uniform spacing had the highest number of commercial seedlings/ha, with three times as many as the forest cut by minimum diameter three years ago and twice as many as the forest treated by minimum diameters 30 years ago. The forest cut by uniform spacing and the forest treated by minimum diameters 30 years ago had the highest diversity of understory plants other than trees, as well as heterogeneous canopy cover, while the other two forests had a predominance of bamboo in the understory and more open canopy conditions. Although lack of site replication limits interpretation of the results, these early findings suggest that the uniform spacing method can be an ecologically sound forest management option for the region.
Effects of Canopy Gaps, Topography, and Soils on the Distribution of Woody Species in a Central Brazilian Deciduous Dry Forest1
Authors: Oliveira‐Filho Ary T. , Curi Nilton , Vilela Enivanis A. , Carvalho Douglas A. 
Published: March 2006

ABSTRACTThe interrelationships between the distribution of woody species and environmental variables were investigated in an area of deciduous dry forest in Santa Vitöria, central Brazil. This is the first study of a vanishing type of dry forest which grows on base‐rich soils originating from the basalt bedrocks of southern Goiás and western Minas Gerais. A survey of topography, soil properties, canopy gaps and woody plants (≥5 cm diameter at the base of the stem) was conducted in 50–15 × 15 m quadrats. The soils were classified into the following soil series: Hapludolls → Haplustolls → Haplustolls → Ustropepts → Rhodustalfs. This series corresponded to a gradient of increasing elevation and effective soil depth and decreasing slope gradient, soil organic matter and total exchangeable bases. A canonical correspondence analysis and a detrended correspondence analysis indicated that plant species’abundance distribution was significantly correlated with both the relative area of canopy gaps in the quadrats and the soil‐topography gradient. Presumably, the critical factors involved in these two gradients are, respectively, light and ground water regimes. The influence of canopy gaps (i.e., light) was surprising and has not been documented previously for tropical deciduous dry forests.
Hurricane Disturbance, Plant‐Animal Interactions, and the Reproductive Success of a Tropical Shrub1
Authors: Pascarella John B. 
Published: March 2006

ABSTRACTHurricane disturbance may have strong effects on plant‐animal interactions important in plant reproductive success. Components of reproductive success (flowering, pollination, seed predation) in the tropical shrub Ardisia escallonioides (Myrsinaceae) were examined from 1991–1994 in four southern Florida populations. Hurricane Andrew struck three of the four populations on 24 August 1992. Hurricane Andrew delayed flowering by two months in 1992. In 1993 and 1994, the three hurricane‐damaged populations had increased flowering and inflorescence production compared to 1991 and 1992, while the undamaged population had no flowering.Hurricane disturbance had different effects on generalist versus specialist plant‐animal interactions. Species composition and relative abundance of the generalist pollinator community that visits A. escallonioides was similar before and after the hurricane, indicating little effect of the disturbance on this interaction. In contrast, populations of a specialist flower galling moth (Periploca sp., Cosmopterigidae) declined in 1992 following Hurricane Andrew. Although moth populations increased at two of the three sites in 1993, the relative impact of moth predation on seed production was low due to extensive flower production. One moth population suffered local population extirpation for two years, reestablishing itself in November 1994. Hurricane disturbance resulted in a window of opportunity for massive seed production of Ardisia escallonioides in south Florida. Total seed production in 1993 increased twelve to seventy‐three times the 1992 levels. Total seed production declined in 1994, but remained high compared to prehurricane levels.
Effects of Selection Logging on Birds in Northern Belize1
Authors: Whitman Andrew A. , Hagan John M. , Brokaw Nicholas V. L. 
Published: March 2006

ABSTRACTWe compared bird diversity and frequency in selection logged and unlogged forest to determine the effects of recent selection logging on avian biodiversity in a subtropical, moist evergreen forest. We used a combination of mist netting and fixed‐radius point counts to assess bird communities in February and March 1993 in northwestern Belize. Vegetation structure and composition was similar in logged and unlogged forest. The 66 most common species occurred with statistically similar frequency in logged and unlogged forest although 13 species were two times more frequent in intact forest. Numbers of total bird species were similar between logging gaps and the logged forest matrix, and between the logged forest matrix and unlogged forests. A comparison of numbers of species in 26 guilds based on migration strategy, diet, foraging substrate, and height strata also showed them to be similar regardless of logging history. Our results differed from previous studies that reported lower bird species richness and abundance of individual species in logged tropical forests than in unlogged forest. The differences might be explained by the lower logging intensity and/or greater levels of natural disturbance in our study area compared to previous studies.