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Wet Forests (wet + forest)
Kinds of Wet Forests Selected AbstractsChanges in Structure, Composition, and Nutrients During 15 Yr of Hurricane-Induced Succession in a Subtropical Wet Forest in Puerto RicoBIOTROPICA, Issue 4 2010Tamara Heartsill Scalley ABSTRACT The trajectory of hurricane-induced succession was evaluated in a network of forest plots measured immediately before and 3 mo, 5, 10, and 15 yr after the direct impact of a Category 4 hurricane. Comparisons of forest structure, composition, and aboveground nutrients pools were made through time, and between species, life-history groups and geomorphic settings. The hurricane reduced aboveground biomass by 50 percent, causing an immediate decrease in stem density and diversity indices among all geomorphic settings. After 15 yr, basal area and aboveground biomass returned to pre-hurricane levels, while species richness, diversity indices, and stem densities exceeded pre-hurricane levels. Differences in species composition among geomorphic settings had not returned after 15 yr but differences in stem densities and structure were beginning to emerge. Significant differences were observed in the nutrient concentration of the three species that comprised the most aboveground biomass, and between species categorized as secondary high-light species and primary, low-light species. Species whose abundance was negatively correlated with the mature forest dominant also had distinct nutrient concentrations. When total aboveground nutrient pools were compared over time, differences in leaf nutrients among species were hidden by similarities in wood nutrient concentrations and the biomass dominance of a few species. The observed successional trajectory indicates that changes in species composition contributed to fast recovery of aboveground biomass and nutrient pools, while the influence of geomorphic setting on species composition occurs at time scales >15 yr of succession. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source] Inner-crown Microenvironments of Two Emergent Tree Species in a Lowland Wet Forest,BIOTROPICA, Issue 2 2005Catherine L. Cardelús ABSTRACT Vascular epiphyte communities, comprising up to 25 percent of tropical forest flora, contribute to plant diversity and thus ecosystem-level processes; however, one of the proximal determinants of those communities, microclimate, is little studied. Here we present the first comprehensive study of microclimates in the inner crowns of two emergent tree species, Hyeronima alchorneoides and Lecythis ampla, at La Selva Biological Station, Costa Rica. We examined photon flux density, temperature, vapor pressure, and humidity in inner-crown branches during the wet and dry seasons and during the wet-season leafless phase of Lecythis. In both seasons, the percentage daily PFD in foliated Lecythis crowns (9%, wet season; 11%, dry season) was significantly higher than in Hyeronima crowns (5%, both seasons), with the leafless wet-season PFD of Lecythis reaching 23 percent of full sun. Temperature and vapor pressure varied less in Hyeronima than in Lecythis crowns during the dry season. Microenvironmental conditions for epiphytes within Hyeronima crowns were more spatially and temporally homogeneous and were more buffered from ambient conditions than within Lecythis crowns. Growing conditions within the crowns of the same trees and among different trees were measurably different and are likely to affect the structure and composition of the resident epiphyte communities. RESUMEN Las epífitas vasculares representan el 25 por ciento de la flora vascular en bosques tropicales. Sin embargo, existe poca información sobre el microclima en que estas plantas habitan. Comparamos flujo fotosintético (PFD), temperatura, presión de vapor y humedad en las ramas interiores de dos especies de árboles emergentes, Hyeronima alchorneoides y Lecythis ampla, en la Estación Biológica La Selva, Costa Rica. En cada estación, se encontró una diferencia significativa entre el por ciento PFD en el dosel de Lecythis (9%, estación lluviosa; 11%, estación seca) y el por ciento PFD registrado en Hyeronima (5.6%, los dos estaciones), con por ciento PFD de Lecythis en la época sin hojas llegando a 23 por ciento. Las copas de Hyeronima mostraron menos variación en temperatura y presión de vapor que las copas de Lecythis durante la época seca. El microclima en el dosel de Hyeronima fue más homogéneo espacialmente y temporalmente y más regulado en comparación con el microclima en Lecythis. Las condiciones de crecer en el dosel de un árbol y entre diferentes árboles son diferentes, y probablemente afectan la estructura y composición de las comunidades de epífitas. [source] Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forestGLOBAL CHANGE BIOLOGY, Issue 2 2006YIQING LI Abstract Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C allocation and the response of different C pools to nutrient addition in these forests remain poorly understood. We measured soil organic carbon (SOC), litterfall, root biomass, microbial biomass and soil physical and chemical properties in a wet tropical forest from May 1996 to July 1997 following a 7-year continuous fertilization. We found that although there was no significant difference in total SOC in the top 0,10 cm of the soils between the fertilization plots (5.42±0.18 kg m,2) and the control plots (5.27±0.22 kg m,2), the proportion of the heavy-fraction organic C in the total SOC was significantly higher in the fertilized plots (59%) than in the control plots (46%) (P<0.05). The annual decomposition rate of fertilized leaf litter was 13% higher than that of the control leaf litter. We also found that fertilization significantly increased microbial biomass (fungi+bacteria) with 952±48 mg kg,1soil in the fertilized plots and 755±37 mg kg,1soil in the control plots. Our results suggest that fertilization in tropical forests may enhance long-term C sequestration in the soils of tropical wet forests. [source] Estimating soil carbon fluxes following land-cover change: a test of some critical assumptions for a region in Costa RicaGLOBAL CHANGE BIOLOGY, Issue 2 2004Jennifer S. Powers Abstract Changes in soil carbon storage that accompany land-cover change may have significant effects on the global carbon cycle. The objective of this work was to examine how assumptions about preconversion soil C storage and the effects of land-cover change influence estimates of regional soil C storage. We applied three models of land-cover change effects to two maps of preconversion soil C in a 140 000 ha area of northeastern Costa Rica. One preconversion soil C map was generated using values assigned to tropical wet forest from the literature, the second used values obtained from extensive field sampling. The first model of land-cover change effects used values that are typically applied in global assessments, the second and third models used field data but differed in how the data were aggregated (one was based on land-cover transitions and one was based on terrain attributes). Changes in regional soil C storage were estimated for each combination of model and preconversion soil C for three time periods defined by geo-referenced land-cover maps. The estimated regional soil C under forest vegetation (to 0.3 m) was higher in the map based on field data (10.03 Tg C) than in the map based on literature data (8.90 Tg C), although the range of values derived from propagating estimation errors was large (7.67,12.40 Tg C). Regional soil C storage declined through time due to forest clearing for pasture and crops. Estimated CO2 fluxes depended more on the model of land-cover change effects than on preconversion soil C. Cumulative soil C losses (1950,1996) under the literature model of land-cover effects exceeded estimates based on field data by factors of 3.8,8.0. In order to better constrain regional and global-scale assessments of carbon fluxes from soils in the tropics, future research should focus on methods for extrapolating regional-scale constraints on soil C dynamics to larger spatial and temporal scales. [source] The role of tropical dry forest as a long-term barrier to dispersal: a comparative phylogeographical analysis of dry forest tolerant and intolerant frogsMOLECULAR ECOLOGY, Issue 22 2007ANDREW J. CRAWFORD Abstract We used a comparative phylogeographical approach to investigate the origins of the disjunct wet forest biota of the Golfo Dulce region along the Pacific slope of Costa Rica. This region is isolated by Pacific dry forests north and south and isolated from Caribbean wet forests by mountains. We studied three sympatric lowland frog species in the Craugastor fitzingeri species group that prefer wet forest but differ in their response to dry habitats. In dry forest, C. fitzingeri can survive along streams while C. crassidigitus and C. talamancae are entirely absent. We collected samples from across the ranges of all three species, and obtained mitochondrial DNA sequence data from the COI and cytochrome b genes. We observed significant phylogeographical structure in C. crassidigitus and C. talamancae, but much less in C. fitzingeri, demonstrating that mountain barriers and dry forest habitat have reduced mitochondrial gene flow in the strictly wet-forest species. Additionally, we discovered that the Golfo Dulce and Central Panama populations of C. crassidigitus appear to have diverged in the Pliocene or earlier, suggesting that the dry forest separating these populations is old. Our phylogenetic analysis of 12 of approximately 16 species of the C. fitzingeri species group suggests that the three lowland species are each other's closest relatives. Because of this shared phylogenetic history, we attribute the striking differences in phylogeographical structure to the different ecologies of the frogs. In summary, we find that what appear to be minor differences in the natural history of these three closely related species may profoundly impact the potential for dispersal, range size, and cladogenesis. [source] First record of tool use by wild populations of the yellow-breasted capuchin monkey (Cebus xanthosternos) and new records for the bearded capuchin (Cebus libidinosus)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2009Gustavo Rodrigues Canale Abstract Reports on use of stones as hammers and anvils to open hard nuts by wild capuchin monkeys are scarce and limited to Cebus libidinosus. Here, we report for the first time data on tool use,stones as hammer and anvils to open nuts,in wild C. xanthosternos and a description of new tool using sites for C. libidinosus. Our records were made by visiting anvil sites and by information obtained from local residents. We surveyed three different biomes: Caatinga (dry forest and thorn scrub), Cerrado (Brazilian bush savannah), and Atlantic forest (wet forest), all records of tool use were from Caatinga or transitional areas between habitats. The behavior is suggested to be routinely performed and widespread among several populations. The fruits of six plant species in different localities were opened with hammer stones by C. xanthosternos. Hammer stones were of similar weigh as those described in other studies of C. libidinosus. Conditions found in Caatinga, such as a more frequent use of the ground by the monkeys and/or food scarcity, may play an important role in the acquisition of nut-cracking behavior. The absence of more reports of nut cracking and other forms of tool use in other species of wild Cebus is likely to result from a lack of surveys in very dry and food limited habitats or intrinsic characteristics of other Cebus species. Am. J. Primatol. 71:366,372, 2009. © 2009 Wiley-Liss, Inc. [source] Diet of spider monkeys (Ateles geoffroyi) in Mesoamerica: current knowledge and future directionsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2009Arturo González-Zamora Abstract Here we review all published articles and book chapters, as well as unpublished theses and data of Ateles geoffroyi diet to (1) summarize the literature; (2) synthesize general feeding patterns; (3) document plant taxonomic similarity in diet across study sites; and (4) suggest directions for future research and conservation priorities. We found 22 samples from five countries: Mexico, Guatemala, El Salvador, Costa Rica and Panama. Tropical wet forest is the most studied habitat (N=13 samples), followed by tropical dry forest (6) and tropical moist forest (3). Most samples have been carried out in large protected forests. In spite of showing an overall high dietetic diversity (364 species, 76 families), A. geoffroyi concentrated the majority of feeding time on a few species in the families Moraceae and Fabaceae. At all study sites fruits were the most common food item in the diet followed by leaves. Furthermore, a greater variety of food items and less fruit were consumed in forest fragments. These findings suggest that fruit shortage in fragments results in primates using foods of presumably lower energetic content such as leaves. Similarity in diet was higher among groups geographically closer to each other than among distant groups, showing that the floristic and phenological characteristics of the forest can influence diet composition. We conclude that several years of data are required to fully describe the dietary list of A. geoffroyi at any one site, as studies of the same group over different years shared as little as 56% of species. As most populations of A. geoffroyi live in highly fragmented landscapes, it is crucial to carry out studies in these areas to evaluate (1) changes in diet and activity patterns that may negatively affect survival; and (2) habitat attributes that may favor their persistence in altered landscapes. Am. J. Primatol. 71:8,20, 2009. © 2008 Wiley-Liss, Inc. [source] Variable strength of top-down effects in Nothofagus forests: bird predation and insect herbivory during an ENSO eventAUSTRAL ECOLOGY, Issue 4 2009C. NOEMI MAZIA Abstract Predators are thought to play a key role in controlling herbivory, thus having positive indirect effects on plants. However, evidence for terrestrial trophic cascades is still fragmentary, perhaps due to variation in top-down forces created by environmental heterogeneity. We examined the magnitude of predation effects on foliar damage by chewing insects and mean leaf size, by excluding birds from saplings in ,dry' and ,wet'Nothofagus pumilio forests in the northern Patagonian Andes, Argentina. The experiment lasted 2 years encompassing a severe drought during the La Niña phase of a strong El Niño/Southern Oscillation event, which was followed by unusually high background folivory levels. Insect damage was consistently higher in wet than in dry forest saplings. In the drought year (1999), bird exclusion increased folivory rates in both forests but did not affect tree leaf size. In the ensuing season (2000), leaf damage was generally twice as high as in the drought year. As a result, bird exclusion not only increased the extent of folivory but also significantly decreased sapling leaf size. The latter effect was stronger in the wet forest, suggesting compensation of leaf area loss by dry forest saplings. Overall, the magnitude of predator indirect effects depended on the response variable measured. Insectivorous birds were more effective at reducing folivory than at facilitating leaf area growth. Our results indicate that bird-initiated trophic cascades protect N. pumilio saplings from insect damage even during years with above-normal herbivory, and also support the view that large-scale climatic events influence the strength of trophic cascades. [source] Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forestGLOBAL CHANGE BIOLOGY, Issue 2 2006YIQING LI Abstract Wet tropical forests play a critical role in global ecosystem carbon (C) cycle, but C allocation and the response of different C pools to nutrient addition in these forests remain poorly understood. We measured soil organic carbon (SOC), litterfall, root biomass, microbial biomass and soil physical and chemical properties in a wet tropical forest from May 1996 to July 1997 following a 7-year continuous fertilization. We found that although there was no significant difference in total SOC in the top 0,10 cm of the soils between the fertilization plots (5.42±0.18 kg m,2) and the control plots (5.27±0.22 kg m,2), the proportion of the heavy-fraction organic C in the total SOC was significantly higher in the fertilized plots (59%) than in the control plots (46%) (P<0.05). The annual decomposition rate of fertilized leaf litter was 13% higher than that of the control leaf litter. We also found that fertilization significantly increased microbial biomass (fungi+bacteria) with 952±48 mg kg,1soil in the fertilized plots and 755±37 mg kg,1soil in the control plots. Our results suggest that fertilization in tropical forests may enhance long-term C sequestration in the soils of tropical wet forests. [source] Maximum size distributions in tropical forest communities: relationships with rainfall and disturbanceJOURNAL OF ECOLOGY, Issue 3 2008Lourens Poorter Summary 1The diversity and structure of communities are partly determined by how species partition resource gradients. Plant size is an important indicator of species position along the vertical light gradient in the vegetation. 2Here, we compared the size distribution of tree species in 44 Ghanaian tropical forest communities, using data from 880 one-hectare plots and over 118 000 trees belonging to more than 210 species. 3The size distribution of forest species showed a continuous normal or log-normal distribution, with many canopy species and a few large species, and varied from community to community. Multiple regression showed that this variation is related to rainfall and to disturbance. 4Size distributions in wet forests were less skewed than those in dry forests, with a smaller proportion of big species and a smaller size range. At the same time they exhibited tighter species packing, resulting in higher species richness. Communities with high disturbance have less species packing and lower species richness. 5Synthesis. We conclude that the factors that constrain organism size and species coexistence in these tropical forest tree communities differ from those known to operate on a number of well-studied animal communities. [source] The role of tropical dry forest as a long-term barrier to dispersal: a comparative phylogeographical analysis of dry forest tolerant and intolerant frogsMOLECULAR ECOLOGY, Issue 22 2007ANDREW J. CRAWFORD Abstract We used a comparative phylogeographical approach to investigate the origins of the disjunct wet forest biota of the Golfo Dulce region along the Pacific slope of Costa Rica. This region is isolated by Pacific dry forests north and south and isolated from Caribbean wet forests by mountains. We studied three sympatric lowland frog species in the Craugastor fitzingeri species group that prefer wet forest but differ in their response to dry habitats. In dry forest, C. fitzingeri can survive along streams while C. crassidigitus and C. talamancae are entirely absent. We collected samples from across the ranges of all three species, and obtained mitochondrial DNA sequence data from the COI and cytochrome b genes. We observed significant phylogeographical structure in C. crassidigitus and C. talamancae, but much less in C. fitzingeri, demonstrating that mountain barriers and dry forest habitat have reduced mitochondrial gene flow in the strictly wet-forest species. Additionally, we discovered that the Golfo Dulce and Central Panama populations of C. crassidigitus appear to have diverged in the Pliocene or earlier, suggesting that the dry forest separating these populations is old. Our phylogenetic analysis of 12 of approximately 16 species of the C. fitzingeri species group suggests that the three lowland species are each other's closest relatives. Because of this shared phylogenetic history, we attribute the striking differences in phylogeographical structure to the different ecologies of the frogs. In summary, we find that what appear to be minor differences in the natural history of these three closely related species may profoundly impact the potential for dispersal, range size, and cladogenesis. [source] Epiphytic ferns and bryophytes of Tasmanian tree-ferns: A comparison of diversity and composition between two host speciesAUSTRAL ECOLOGY, Issue 2 2005NINA R. ROBERTS Abstract Ferns, bryophytes and lichens are the most diverse groups of plants in wet forests in south-eastern Australia. However, management of this diversity is limited by a lack of ecological knowledge of these groups and the difficulty in identifying species for non-experts. These problems may be alleviated by the identification and characterization of suitable proxies for this diversity. Epiphytic substrates are potential proxies. To evaluate the significance of some epiphytic substrates, fern and bryophyte assemblages on a common tree-fern species, Dicksonia antarctica (soft tree-fern), were compared with those on a rare species, Cyathea cunninghamii (slender tree-fern), in eastern Tasmania, Australia. A total of 97 fern and bryophyte species were recorded on D. antarctica from 120 trunks at 10 sites, and 64 species on C. cunninghamii from 39 trunks at four of these sites. The trunks of C. cunninghamii generally supported fewer species than D. antarctica, but two mosses (particularly Hymenodon pilifer) and one liverwort showed significant associations with this host. Several other bryophytes and epiphytic ferns showed an affinity for the trunks of D. antarctica. Species assemblages differed significantly between both sites and hosts, and the differences between hosts varied significantly among sites. The exceptionally high epiphytic diversity associated with D. antarctica suggests that it plays an important ecological role in Tasmanian forests. Evidently C. cunninghamii also supports a diverse suite of epiphytes, including at least one specialist species. [source] Age-Dependent Radial Increases in Wood Specific Gravity of Tropical Pioneers in Costa RicaBIOTROPICA, Issue 5 2010G. Bruce Williamson ABSTRACT Wood specific gravity is the single best descriptor of wood functional properties and tree life-history traits, and it is the most important variable in estimating carbon stocks in forests. Tropical pioneer trees produce wood of increasing specific gravity across the trunk radius as they grow in stature. Here, we tested whether radial increases in wood specific gravity were dependent on a tree's diameter or its age by comparing trees of different diameters within cohorts. We cored trunks of four pioneer species in naturally regenerating, even-aged stands in the lowland, wet forests of Costa Rica. For each core, specific gravity was determined for 1-cm radial wood segments, pith to bark. Increases across the radius were evident in all four species studied, and in four different stands for one species. For any given species in a given stand, the rate of radial increase in specific gravity as a function of radial distance from the pith was greater in smaller diameter trees. As the trees in a stand represent a colonizing cohort, these results strongly suggest that the radial increases in specific gravity in lowland pioneers are associated with tree age, not with tree diameter. Furthermore, the specific gravity of the outermost wood was not associated with tree radius, further negating size dependence. One consequence of these results is that species-specific biomass estimates for trees in secondary forests are likely to be confounded by age, as diameter alone may be a poor indicator of specific gravity in individual trees for pioneers of tropical wet forests. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source] Phyllostomid Bat Community Structure and Abundance in Two Contrasting Tropical Dry Forests,BIOTROPICA, Issue 4 2005Kathryn E. Stoner ABSTRACT Although tropical wet forests are generally more diverse than dry forests for many faunal groups, few studies have compared bat diversity among dry forests. I compared ground level phyllostomid bat community structure between two tropical dry forests with different precipitation regimes. Parque National Palo Verde in northwestern Costa Rica represents one of the wettest tropical dry forests (rainfall 1.5 m/yr), whereas the Chamela-Cuixmala Biosphere Reserve on the Pacific coast of central Mexico represents one of the driest (750 mm/yr). Mist net sampling was conducted at the two study sites to compare changes in ground level phyllostomid bat community structure between regions and seasons. Palo Verde was more diverse than Chamela and phyllostomid species showed low similarity between sites (Classic Jaccard = 0.263). The distinct phyllostomid communities observed at these two dry forest sites demonstrates that variants of tropical dry forest can be sufficiently different in structure and composition to affect phyllostomid communities. At both dry forest sites, abundance of the two most common foraging guilds (frugivores and nectarivores) differed between seasons, with greatest numbers of individuals captured coinciding with highest chiropterophilic resource abundance. RESUMEN A pesar de que los bosques tropicales húmedos, en general, son más diversos que los bosques tropicales secos para muchos grupos de fauna, pocos estudios han comparado la diversidad de murciélogos en los bosques tropicales secos. El presente estudio compara la estructura de la comunidad de los murciélagos filostómidos a nivel del suelo entre dos tipos de bosque tropical seco con diferentes regimenes de precipitación. El parque Nacional Palo Verde esta localizado en el Noroeste de Costa Rica y representa uno de los bosques tropicales secos mas húmedos (con una precipitación de 1.5 m/año), mientras que la Reserva de la Biosfera Chamela-Cuixmala esta localizada en la costa oeste del pacífico de México y representa uno de los bosques más secos (750 mm/año). Se realizó un muestreo con redes de niebla en los dos sitios para comparar los cambios en la estructura de la comunidad de murciélagos filostómidos a nivel de suelo. Palo Verde fue más diverso que Chamela y se encontró la simultud de las especies filostomidos entre los dos sitio fue bajo (Classic Jaccard = 0.263). Las comunidades distintas de filostomidos observado en estos dos sitios de bosque seco demuestra que las variantes en el bosque tropical seco pueden ser suficientemente diferentes en estructura y composición para poder afectar la comunidad de filostomidos. En ambos bosques secos la abundancia de lo dos gremios tróficos más comunes (frugívoros y nectarívoros) fue diferente en las estaciones, con un mayor número de individuos capturados coincidiendo con una mayor abundancia de recursos quiropterofílicos. [source] | ||||||||||