نتایج جستجو برای: tropical forests
تعداد نتایج: 102462 فیلتر نتایج به سال:
Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the re-5 sults of high frequency (ca. 1 min −1) methane measurements cond...
The functional role of herbivores in tropical rainforests remains poorly understood. We quantified the magnitude of, and underlying controls on, carbon, nitrogen and phosphorus cycled by invertebrate herbivory along a 2800 m elevational gradient in the tropical Andes spanning 12°C mean annual temperature. We find, firstly, that leaf area loss is greater at warmer sites with lower foliar phospho...
Condit et al. (1) and Duivenvoorden et al. (2) discussed beta-diversity of tropical rainforest trees and came to some conclusions that we find problematic. Condit et al. argued that betadiversity of lowland rainforest trees is higher in Panama than in western Amazonia, based on observation of a steeper distance-decay of floristic similarity in 34 Panamanian tree plots compared with 16 Ecuadoria...
*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent droug...
Observations of the tropical nitrogen (N) cycle over the past half century indicate that intact tropical forests tend to accumulate and recycle large quantities of N relative to temperate forests, as evidenced by plant and soil N to phosphorus (P) ratios, by P limitation of plant growth in some tropical forests, by an abundance of N-fixing plants, and by sustained export of bioavailable N at th...
The response of tropical forests to climate change will depend on individual plant species' nutritional strategies, which have not been defined in the case of the nitrogen nutrition that is critical to sustaining plant growth and photosynthesis. We used isotope natural abundances to show that a group of tropical plant species with diverse growth strategies (trees and ferns, canopy, and subcanop...
Australian rain forests extend from tropical climates in the north to temperate climates in the south, providing an opportunity to investigate physiological responses to temperature of both temperate and tropical species within the same forest type. Eight, rain forest canopy tree species were selected to cover the 33 degrees latitudinal range of rain forests in eastern Australia. Temperature to...
In the present study, Randomly Amplified Polymorphic DNA (RAPD) markers were used to analyze the genetic diversity in 20 varieties of Philodendron. The polymerase chain reaction was performed with 60 RAPD primers, out of which 21 primers showed clear amplification as well as more polymorphism. In total, 354 scorable RAPD loci with 348 polymorphic bands (98%) were observed. Percentages of polymo...
Global com parisons suggest that rates o f N fixation in tropical rain forests m ay be am ong the highest on earth. However, data supporting this contention are rare, and the factors th a t regulate N hxation w ithin the biom e rem ain largely unknow n. W e conducted a full-factorial (N X P) fertilization experim ent in two lowland tropical rain forests in C osta Rica to explore the effects o f...
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