Leaf litter

The effects that changes in vegetation have on soil carbon pools and nutrient availability are also difficult to evaluate. However, several models have been successful in predicting vegetation-soil nutrient relationships because they assume that such changes occur as a result of different rates of decomposition and nutrient release from leaf litter of different taxa 50, 60), Such predictions could be tested and the models refined or parameterized for new taxa by measuring soil nutrient availability and respiration in stands of different species on the same soil type. For example, fifty years ago the U.S. Civilian Conservation Corps (CCC) established such stands as species trial plots measurements in some indicate large differences in soil nutrient availability (48), Further measurements in these stands would now occur at the same time-scale at which we expect the feedback between species replacement and soil processes to occur. 

Land use changes in the tropics have resulted in a landscape characterized as a mosaic of logged forests, cleared fields, and successional forests. This results in the transformation from extremely fire resistant rainforest ecosystems to anthropogenic landscapes in which fire is a common event (16, 17), Fires occur in disturbed tropical forests because deforestation has a dramatic effect on microclimate. Deforestation results in lower relative humidities, increased wind speeds, and increased air temperatures. In addition, deforestation results in increased quantities of biomass that are susceptible to fire. This biomass may be in the form of forest slash, leaf litter, grasses, lianas or herbaceous species (16, 18). 

Langhans SD, Tockner K (2006) The role of timing, duration, and frequency of inundation in controlling leaf-litter decomposition in a river-floodplain ecosystem (Tagliamento, NE Italy). Oecologia 147 501-509... 

Sydes, C. Grime, J.P. (1981a). Effects of tree leaf litter on herbaceous vegetation in deciduous woodland. I. Field investigations. Journal of Ecology, 69, 237-48. 

Cu2+ 20 pM Indigenous community Leaf litter immersed in stream 63... 

Duarte, S., Pascoal, C., Alves, A., Correia, A., and Cassio, F., Copper and zinc mixtures induce shifts in microbial communities and reduce leaf litter decomposition in streams, Freshwater Biol, 53 (1), 91-101, 2008. 

The allelopathic effects of dominant plants on other plants in phytocoenosis are caused by phenolic phytotoxins present in all parts of plants, but the highest amount of these compounds is accumulated in the leaves. Leaves of dominant trees represent the main components of the litter in the forest, thus analysis of phenolic compounds and measurements of their content in leaves and leaf litter is considered as very important. 

The use of terrestrial invertebrates as sentinel organisms has been suggested for monitoring lead. The spider Araneus umbricatus, for example, contained lead body burdens that correlated with that in a lichen (Lecanora conizaeoides) that is used to monitor atmospheric lead (Clausen 1984). Similarly, the woodlouse (Porcellio scaber) seems to reflect lead concentrations in adjacent soil or leaf litter (Hopkin et al. 1986). 

Whole-body zinc content of terrestrial isopods seems to reflect soil zinc levels and may be a useful indicator of soil contamination (Hopkin et al. 1989). Porcellio scaber, a terrestrial isopod known as a woodlouse, is recommended as a biological indicator of zinc contamination because of the positive correlation between zinc content in soil or leaf litter and woodlouse hepatopancreas. Zinc content in Porcellio, litter, and soil near a zinc smelter, in mg/kg DW, was >1000 in whole isopod, >9000 in hepatopancreas, >10,000 in titter, and >50,000 in soil (Hopkin et al. 1986). 

Increased algal growth on leaf litter observed months after treatment, attributed to reduction in grazing stress by mosquito larvae (Hagmann and Porteus 1972)... 

Swift, M.C., K.W. Cummins, and R.A. Smucker. 1988a. Effects of dimilin on stream leaf-litter processing rates. Ver. Inter. Verein, Theoret. Ange. Limnol. 23 1255-1260. 

Mangrove ecosystems are an example of one of the most productive ecosystems of the World. The biomass pool is in excess of 100 ton/ha of dry matter and annual NPP varies from 10 to 30 ton/ha, including leaf litter production of 8-15 ton/ha. Using average data on annual net primary production and content of various elements, we... 

Two classes of dendrobatid alkaloids have potential dietary sources. The first are the pyrrolizidine oximes (32), whose carbon skeleton is identical to that of nitropolyzonamine, an alkaloid from a small millipede (33). Indeed, raising the dendrobatid frog D. auratus in Panama on leaf-litter arthropods, gathered weekly, resulted in skin levels of the... 

Ktlsel K, Drake HL. 1996. Anaerobic capacities of leaf litter. Appl Environ... 

A hedge (see also pp.142-145) is an excellent place for creatures to take shelter from predators or the weather, court, mate, and feed, as well as build a nest. In windy winter conditions, a hedge is warmer and stays dry at the base. A hedge base full of leaf litter is also a rich food source for insect eaters—not only birds but also toads, voles, and shrews. 

Herbs that enjoy dappled shade thrive on the edges of shrubs or by groups of small trees. Add a low-fertility soil improver on an annual basis in order to mimic the leaf litter layer that occurs naturally in woodland areas. Vigorous... 

Adults and young stages overwinter in soil, leaf litter, and plant debris. 

Jensen, V. Decomposition of angiosperm tree leaf litter, pp. 69-104. In C. H. Dickinson, and G. J. F. Pugh, Eds. Biology of Plant Litter Decomposition. Vol. 1. New York Academic Press, 1974. 

Frogs of the genus Dendrobates are ant specialists. Of the more than 20 structural classes of lipophilic alkaloids found in the frogs, six occur in myrmicine ants. However, many dendrobatid alkaloids such as the batrachotoxins, histri-onicotoxins, and pumiliotoxins, have not yet been found in insects and other leaf-litter prey such as beetles and millipedes (Daly et al., 2000). The snake Lio-phis epinephelus feeds on Dendrobates and may further bioaccumulate alkaloids. 

Possible functions Anti-herbivore inhibition of digestion Protect cell wall against microbes Retard decomposition of leaf litter slow down release of nutrients (assumed to benefit mother plant) Mostly aimed at microbes, not herbivores... 

Allelopathic chemicals from plants may be released from living leaves as volatiles or leachates or from roots through exudation or sloughing off of dead tissues. They also may be leached from leaf litter on the soil surface. 

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