Litter quality influences on decomposition, ectomycorrhizal community structure and mycorrhizal root surface acid phosphatase activity

The influence of litter quality on root growth, ectomycorrhizal communities and decay processes was investigated through a litter bag experiment. Litter bags containing either pine needles, oak leaves or oak+ pine mix were placed within the O horizon of a lowland pitch pine (Pinus rigida) forest in the New Jersey Pinelands. Upon retrieval, ingrown pine roots were removed and quantified for total length and percent ectomycorrhizal colonization by morphotype. Phosphatase activity was determined for dominant morphotypes. In addition, litter decay rates and N and P litter content were measured. Mixed litter (oaks pine) had highest total pine root ingrowth. Dominant ectomycorrhizal morphotypes differed in response to litter type. A tuberculate form dominated (35%) in pine litters while distinctly different nontuberculate morphotypes dominated in oak and mixed litters. High phosphatase activity of morphotypes was correlated with high phosphorus immobilization during oak leaf decay. Results indicate that a mix of forest litters (oak and pine) optimizes retention of scarce nutrients such as nitrogen and phosphorus. The diverse chemical environment of these different litter types induces different ectomycorrhizal community development which show functional differences in the way phosphorus is likely to be cycled. The influence of litter type on diversity and function of ectomycorhizae is an important step in identifying linkages between biodiversity of this group and ecosystem functions. (C) 2000 Elsevier Science Ltd. All rights reserved.