The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Raffaele Lafortezza - One of the best experts on this subject based on the ideXlab platform.
-
air contaminants and Litter Fall decomposition in urban forest areas the case of sao paulo sp brazil
Environmental Research, 2017Co-Authors: Mauricio Lamano Ferreira, Andreza Portella Ribeiro, Caroline Rodrigues Albuquerque, Ana Paula Do Nascimento Lamano Ferreira, Rubens Cesar Lopes Figueira, Raffaele LafortezzaAbstract:Abstract Background Urban forests are usually affected by several types of atmospheric contaminants and by abnormal variations in weather conditions, thus facilitating the biotic homogenization and modification of ecosystem processes, such as nutrient cycling. Peri-urban forests and even natural forests that surround metropolitan areas are also subject to anthropogenic effects generated by cities, which may compromise the dynamics of these ecosystems. Hence, this study advances the hypothesis that the forests located at the margins of the Metropolitan Region of Sao Paulo (MRSP), Brazil, have high concentrations of atmospheric contaminants leading to adverse effects on Litter Fall stock. Methods The production, stock and decomposition of Litter Fall in two forests were quantified. The first, known as Guarapiranga forest, lies closer to the urban area and is located within the MRSP, approximately 20 km from the city center. The second, Curucutu forest, is located 70 km from the urban center. This forest is situated exactly on the border of the largest continuum of vegetation of the Atlantic Forest. To verify the reach of atmospheric pollutants from the urban area, levels of heavy metals (Cd, Pb, Ni, Cu) adsorbed on the Litter Fall deposited on the soil surface of the forests were also quantified. Results The stock of Litter Fall and the levels of heavy metals were generally higher in the Guarapiranga forest in the samples collected during the lower rainFall season (dry season). Non-metric multidimensional scaling multivariate analysis showed a clear distinction of the sample units related to the concentrations of heavy metals in each forest. A subtle difference between the units related to the dry and rainy seasons in the Curucutu forest was also noted. Multivariate Analysis of Variance revealed that both site and season of the year (dry or rainy) were important to differentiate the quantity of heavy metals in Litter Fall stock, although the analysis did not show the interaction between these two factors. Precipitation appeared to be an important factor to disperse air pollutants; one method to better regulate this process is the development and integration of green infrastructure at city level, which might contribute to nature-based solutions. Conclusions Results suggest that although the Curucutu forest is not very far from the MRSP, which could result in heavy metal levels similar to those observed in the Guarapiranga forest, the weather conditions, geographic location and rainFall rates might act as efficient physical barriers against the dispersion of pollutants in the urban area. However, it is important to highlight that in the period studied (2012–2013), MRSP presented unusual features during the winter period marked by the highest levels of precipitation which was due to several numbers of frontal systems and also due to their permanence for a couple days in the region. Thus, it is recommended to continue this study in order to obtain a database for characterizing the seasonal variation of air pollution levels in the Litter Fall and their adverse effects on ecosystem processes in these remnants of the Atlantic Forest.
Shinya Sugita - One of the best experts on this subject based on the ideXlab platform.
-
A spatially explicit model of leaf Litter Fall in hemlock-hardwood forests
Canadian Journal of Forest Research, 1996Co-Authors: James B. Ferrari, Shinya SugitaAbstract:A spatially explicit model of leaf Litter Fall was developed for hemlock–hardwood forests using Litter-trap data from mapped forest plots and from isolated trees. The model assumes that Litter decl...
-
a spatially explicit model of leaf Litter Fall in hemlock hardwood forests
Canadian Journal of Forest Research, 1996Co-Authors: James B. Ferrari, Shinya SugitaAbstract:A spatially explicit model of leaf Litter Fall was developed for hemlock–hardwood forests using Litter-trap data from mapped forest plots and from isolated trees. The model assumes that Litter declines exponentially with distance, as shown by the Litter traps from isolated trees, and that a variable allometric equation describes the relationship of DBH to foliage biomass. Model parameters were estimated by a maximum likelihood method using field data from one mapped plot and then tested on a second plot. Predicted leaf Fall of sugar maple (Acersaccharum Marsh.), yellow birch (Betulaalleghaniensis Britton), basswood (Tiliaamericana L.), and eastern hemlock (Tsugacanadensis (L.) Carriere) was consistent with the leaf Fall measured in 20 traps (r = 0.86, 0.77, 0.95, 0.92, respectively). Data from 100 paired Litter traps show the similarity of Litter Fall at sites 2.7 m apart; trap contents in two successive autumns were also comparable. The model results show that hemlock has the narrowest leaf-Fall shadow, ...
Gerd Gleixner - One of the best experts on this subject based on the ideXlab platform.
-
overstory specific effects of Litter Fall on the microbial carbon turnover in a mature deciduous forest
Forest Ecology and Management, 2009Co-Authors: Christel Baum, Mirko Fienemann, Stephan Glatzel, Gerd GleixnerAbstract:Mature deciduous forests can serve as important carbon (C) sinks, but the C storage differs significantly in dependency on the tree species. To specify the significance of overstory-specific effects of Litter Fall on the soil microbial C turnover, we have investigated the 13C isotopic signature of microbial biomarker phospholipid fatty acids (PLFAs). Samples were taken under pure Fagus sylvatica and mixed overstory (F. sylvatica and Fraxinus excelsior or F. excelsior, Acer spp. and F. sylvatica) in a mature temperate deciduous forest in Central Germany 4 weeks prior to and 3 weeks after Litter Fall. Accordingly, the CO2 emission from soil was measured before, during and after the Litter Fall to investigate the response of decomposition. At all sites and at both sampling dates the fungal biomarker PLFA 18:2ω6,9 had predominantly lower δ13C values (from −32 to −43‰) than the bacterial biomarker PLFAs (δ13C values from −23 to −39‰). This difference indicated that fungi generally used preferentially plant derived C, whereas the bacterial populations include groups which used SOM derived C, independent on the overstory trees. Under pure F. sylvatica overstory the δ13C values of microbial biomarker PLFAs were slightly decreased (up to 2‰ for 17:0br) or unchanged after Litter Fall. By contrast, under both variants of mixed overstory the δ13C values of biomarker PLFAs of fungi (18:2ω6,9) were increased after Litter Fall (+3.5 and +3.8‰). This might be explained partly by a faster initial decomposition of foliar Litter from mixed overstory already during Litter Fall as confirmed by higher CO2 emission under mixed F. excelsior, Acer spp. and F. sylvatica than under pure F. sylvatica in this period. However, the involved microbial populations differed overstory-specific. Bacterial biomarker PLFAs with strongest overstory-specific differences in the response on Litter Fall were 17:0br (Gram-positive bacteria), 18:1 and 19:0cy (Gram-negative bacteria). The present results indicate that a tree species conversion even exclusively between deciduous tree species might alter the soil microbial C turnover during Litter decomposition and suggest that it would in the long-term change the SOM stability and C storage.
Nico Koedam - One of the best experts on this subject based on the ideXlab platform.
-
Are Peri-Urban Mangroves Vulnerable? An Assessment Through Litter Fall Studies
Estuaries of the World, 2016Co-Authors: Mohamed Omar Said Mohamed, Perrine Mangion, Steve Mwangi, James G Kairo, Farid Dahdouh-guebas, Nico KoedamAbstract:The productivity of an over-exploited and sewage polluted peri-urban mangrove was assessed through Litter Fall studies to establish vulnerability to human actions and climate change. Litter from three common mangrove species, Rhizophora mucronata Lam. (Rhizophoraceae), Sonneratia alba Sm. (Sonneratiaceae), and Avicennia marina (Forssk.) Vierh. (Avicenniaceae) were monitored over a period of two years. The mean annual Litter Fall was estimated at 12.16 ± 2.89 t ha−1yr−1. Litter Fall was seasonal in both content and quantity, with high rates occurring in the dry North Easterly Monsoon (NEM) season, January-April (ca. 5.10 ± 1.36 g DW m−2 day−1) and lower rates in the cool and wet South Easterly Monsoon (SEM) season, June-October (ca. 2.53 ± 0.47 g DW m−2 day−1). Litter Fall varied significantly between species, R. mucronata recording the highest annual rate (15.34 ± 3.34 t ha−1yr−1), with no significant difference between A. marina and S. alba, (11.44 ± 2.90 and 9.69 ± 5.26 t ha−1yr−1 respectively). Sewage exposure did not affect Litter Fall rates for all species, but affected leaf nutrient content as expressed by the leaf δ15N signature. A strong correlation between leaf C:N ratio and leaf δ15N signature was observed, indicating a more open N cycle, favouring δ15N accumulation. Sewage exposure therefore does not necessarily translate into elevated productivity in mangroves, but causes alteration of leaf nutrient content depending on species. Prevailing climatic conditions however, may influence Litter Fall and thus phenology and health of the system. The vulnerability of the Tudor Creek mangroves to climate change may be ranked high due to low production (20%
-
are peri urban mangroves vulnerable an assessment through Litter Fall studies
Estuaries of the World, 2016Co-Authors: Mohamed Omar Said Mohamed, Perrine Mangion, Steve Mwangi, James G Kairo, Farid Dahdouhguebas, Nico KoedamAbstract:The productivity of an over-exploited and sewage polluted peri-urban mangrove was assessed through Litter Fall studies to establish vulnerability to human actions and climate change. Litter from three common mangrove species, Rhizophora mucronata Lam. (Rhizophoraceae), Sonneratia alba Sm. (Sonneratiaceae), and Avicennia marina (Forssk.) Vierh. (Avicenniaceae) were monitored over a period of two years. The mean annual Litter Fall was estimated at 12.16 ± 2.89 t ha−1yr−1. Litter Fall was seasonal in both content and quantity, with high rates occurring in the dry North Easterly Monsoon (NEM) season, January-April (ca. 5.10 ± 1.36 g DW m−2 day−1) and lower rates in the cool and wet South Easterly Monsoon (SEM) season, June-October (ca. 2.53 ± 0.47 g DW m−2 day−1). Litter Fall varied significantly between species, R. mucronata recording the highest annual rate (15.34 ± 3.34 t ha−1yr−1), with no significant difference between A. marina and S. alba, (11.44 ± 2.90 and 9.69 ± 5.26 t ha−1yr−1 respectively). Sewage exposure did not affect Litter Fall rates for all species, but affected leaf nutrient content as expressed by the leaf δ15N signature. A strong correlation between leaf C:N ratio and leaf δ15N signature was observed, indicating a more open N cycle, favouring δ15N accumulation. Sewage exposure therefore does not necessarily translate into elevated productivity in mangroves, but causes alteration of leaf nutrient content depending on species. Prevailing climatic conditions however, may influence Litter Fall and thus phenology and health of the system. The vulnerability of the Tudor Creek mangroves to climate change may be ranked high due to low production (20%<) of reproductive materials and a die back of seaward fringe S. alba stand.
Juli G Pausas - One of the best experts on this subject based on the ideXlab platform.
-
Litter Fall and Litter decomposition in pinus sylvestris forests of the eastern pyrenees
Journal of Vegetation Science, 1997Co-Authors: Juli G PausasAbstract:Abstract. Litter Fall and Litter decomposition were studied in four mature stands of Pinus sylvestris (Scots pine) in the eastern Pyrenees. The stands were located in environments differing in bedrock type and exposition and were studied for two years. Mass-loss during the first year of decomposition was compared with other European P. sylvestris forests and regressed with environmental variables (temperature and rainFall) and latitude. The results suggested that the mean amount of needle Fall (1760 kg-ha-1·yr-1) was within the range reported for northern European stands. There were more differences in the amount of Litter Fall between the four stands than between the two years studied. However, the needle Fall pattern over the year showed significant differences between years in three of the four stands. Litter decomposition was similar in all the stands and only the one in drier conditions showed a lower decomposition rate. On the European scale the decomposition rate was positively related to mean annual temperature and annual rainFall. However, regression analysis suggests that there are other factors, not taken into account in this study, that are important for predicting the decomposition rate.