查看更多>>摘要：To investigate the effect of surrounding tree density and the topography of the site of the host tree on the abundance, species richness, and diversity of epiphytic orchids, 32 trees of Schima wallichii were chosen randomly and the epiphytic orchids were counted and identified. Within a circle of radius 20m from each host tree, trees with diameter at breast height (DBH) greater than 20 cm had their species name and DBH recorded. In addition, the angle and direction of slope on which the host tree stood were measured. DBH of host trees affected epiphytic orchid abundance, species richness, and diversity positively. Density of trees surrounding each host tree, steepness and being on a north facing slope had a negative effect on epiphytic orchid abundance. However, species richness and the diversity of epiphytic orchids were not affected by any of the host conditions.
查看更多>>摘要：Age-related changes in root morphology and physiology, and the relationship with N dynamics between species that differ in resource use (i.e., conservative or acquisitive) and lifespan strategies are largely unexplored and experimental evidence very scarce.
查看更多>>摘要：Fruit type composition (dry or fleshy) can substantially influence plant community function. Many studies have researched how fruit type changes with elevation gradient in montane regions; however, these data are lacking for climbing plants. Climbing plants have unique functional traits and requirements, determined by a diversity of factors. Here we analyzed the fruit type produced by 245 climbing plant species collected along a 3-km elevational gradient in a subtropical forest ecosystem in China. We found that woody lianas showed a monotonic increase (McFadden's R-2 = 0.164) in the proportion of fleshy-fruited species, while herbaceous vines showed a unimodal pattern (McFadden's R-2 = 0.080). The results remained consistent after taking phylogenetic correlation among species into account. This clear relationship suggests that for climbing plants the change in various environmental factors with elevation is the main driver of the proportion of fleshy-fruited species. Understanding which factors and mechanisms underpin climbing plant fruit types, and thus seed dispersal dynamics, is not only important for conceptual ecology, but also for conservation and predicting forest composition under global change.
Henriques e Souza, Flaviada Silva, Elizamar CiriacoBocchiglieri, Adriana
5页
查看更多>>摘要：Seed dispersal consists of diaspore removal from parental plants and relocation to new locations where seeds can germinate and grow seedlings. Seeds that passage through an animal's digestive tract may have changes in percentages, speed, and synchronization of germination. Cerdocyon thous is an omnivorous canid from South America and we investigated its role as a dispersing agent, in semiarid areas, by analyzing feces in three areas of northeastern Brazil. Seeds found in feces and removed directly from fruit (control) had their viabilities evaluated in germination tests, where germinability, germination time of 50% of viable seeds (t(50)), the emergence velocity, and synchronization indices were determined. Of the evaluated species, the cactus Pilosocereus gounellei showed differences in the parameters between treatments. The passage of seeds of P. gounellei through the canid digestive tract decreased germinability and the germination speed and increased the t(50). For the other species, there were no difference between treatments. Therefore, C. thous influenced the germination success and pattern of this cactus, although it did not influence the reproductive behavior of most species. This canid was considered an effective seed disperser in semiarid areas because it moved seeds from the parental plant to sites suitable for its germination.
查看更多>>摘要：Old-growth tropical forests provide an essential climate regulation service to humans, functioning as carbon (C) sink due to the high productivity, species diversity, and variety of life forms, such as bamboos. Bamboos growth fast and display plastic functional traits, which favor the occupation of environments under different conditions, making them efficient C stockers in addition to providing raw material for local human populations. Asian bamboos are known to sequester considerable amounts of C in a short time, and although is likely that New World bamboo species have the same capacity, this perspective is rarely addressed. To evaluate the impact of a native bamboo on biomass and carbon stocks of an Atlantic Forest Protected Area, we first developed an allometric equation to estimate its live aboveground biomass (AGB) based on the destructive sampling method. We then compare our results to the AGB of forest components previously estimated for the same area, as well as to Asian and other Neotropical bamboo species to place our case study in a global scenario. In four 1-ha permanent plots in Sao Paulo State, Brazil, we made a census of all live culms and collected 20 healthy ones for equations purposes. The Merostachys neesii Rupr. (Poaceae) studied species has 343 clumps ha(-1), 3663 culms ha(-1), and 12.1 Mg ha(-1) of biomass (5.2 Mg C ha(-1)) or 4% of total AGB and C stocks of the studied area. M. neesii's contributes as much as palms solely, but more than lianas and tree ferns together for the total AGB in the old-growth Montane Atlantic Forest we studied. These results show that the non-inclusion of bamboos may underestimate the role of terrestrial ecosystems in buffering anthropogenic CO2. The comprehension of bamboo ecology is crucial for conservation and management purposes, and it is relevant since, with global warming, the C stored may be released turning these ecosystems into source instead of a sink of C.
NSTL
Elsevier