Length–biomass and energy relationships of terrestrial gastropods in northern forest ecosystems

1997 ◽  
Vol 75 (3) ◽  
pp. 501-505 ◽  
Author(s):  
J. W. Hawkins ◽  
M. W. Lankester ◽  
R. A. Lautenschlager ◽  
F. W. Bell
Keyword(s):  
Boreal Forest ◽  
Efficient Method ◽  
Forest Floor ◽  
Forest Ecosystems ◽  
Northern Forest ◽  
Terrestrial Gastropods ◽  
Power Equation ◽  
Biomass Models ◽  
Energy Relationships ◽  
Underlying Soil

Length–biomass models are a convenient and time-efficient method of estimating the biomass of invertebrates. Our purpose was to develop such a model for terrestrial gastropods that adequately predicted gastropod dry tissue biomass (Y) on the basis of animal length (X). The power equation Y = 0.172X1.688 (r2 = 0.85) proved to be the best model for this purpose. Gastropod dry tissue biomass was 6.52 ± 1.58 mg (mean ± SE) and, based on gastropod densities ranging from 2 to 38/m2 reported in the literature, snails and slugs active on the surface of the forest floor accounted for 2.5 and 6% of the total animal biomass and energy, respectively, of boreal forest ecosystems. However, because densities of gastropods in both the litter and underlying soil can reach 1607/m2, our results suggest that published values for total animal biomass (4.9 g/m2) and caloric energy (104 cal/m2) in boreal forest ecosystems are underestimated.

Spatial variability of trace metals in Podzols of northern forest ecosystems: Sampling implications

2003 ◽  
Vol 83 (5) ◽  
pp. 581-587 ◽  
Author(s):  
J. D. MacDonald ◽  
W. H. Hendershot
Keyword(s):  
Trace Metals ◽  
Spatial Variability ◽  
Point Source ◽  
Forest Ecosystems ◽  
Physical Factors ◽  
Individual Plant ◽  
Forest Site ◽  
Organic Carbon Content ◽  
Metal Concentrations ◽  
Northern Forest

The concentrations of metals in soils are spatially heterogeneous and soil sampling carried out when studying metals in forest ecosystems is often inadequate. We examined the spatial variability of Cd, Cu, Mn, Ni, Pb and Zn in northern forest ecosystems on a transect with distance from two point source emitters with the goal of providing basic information about the distribution and variability of metals in these soils. Samples were taken under six sampling points at four depths from three experimental sites on each of the two transects. Soils were analysed for acid digestible metals, pH and organic carbon content. Standard deviation, coefficients of variation, mean and medians were analysed for each horizon of each site. It was observed that Cu and Mn variability is higher in closer proximity to the point source while the variability of Zn increased with decreasing soil pH. In Sudbury, emitted metals Ni and Cu accumulate together in soils, whereas in Rouyn-Noranda, with the exception of Cd and Zn, metal concentrations were not related in forest floors. Observations suggest that physical factors influencing where metals are deposited as well as the inherent variability in soil chemical characteristics, and the distance from the point source can all act together to result in high variability in soil metal concentrations in a single forest site. Sampling in the interest of relating vegetation metal concentrations or response to soil metals should be carried out on an individual plant basis with multiple samples taken for each individual. Soil samples taken at intervals of 1 to 1.7 m will provide relative error in estimating soil concentrations of 10% or 20%, respectively. Key words: Spatial variability, trace metals, podzolic soils, smelter emissions

scholarly journals Microbial Mechanisms Mediating Increased Soil C Storage under Elevated Atmospheric N Deposition

2012 ◽  
Vol 79 (4) ◽  
pp. 1191-1199 ◽  
Author(s):  
Sarah D. Eisenlord ◽  
Zachary Freedman ◽  
Donald R. Zak ◽  
Kai Xue ◽  
Zhili He ◽  
...  
Keyword(s):  
Forest Floor ◽  
Forest Ecosystems ◽  
N Deposition ◽  
Fungal Communities ◽  
Functional Genes ◽  
Atmospheric N Deposition ◽  
Soil C ◽  
C Storage ◽  
Genes Encoding ◽  
Soil C Storage

ABSTRACTFuture rates of anthropogenic N deposition can slow the cycling and enhance the storage of C in forest ecosystems. In a northern hardwood forest ecosystem, experimental N deposition has decreased the extent of forest floor decay, leading to increased soil C storage. To better understand the microbial mechanisms mediating this response, we examined the functional genes derived from communities of actinobacteria and fungi present in the forest floor using GeoChip 4.0, a high-throughput functional-gene microarray. The compositions of functional genes derived from actinobacterial and fungal communities was significantly altered by experimental nitrogen deposition, with more heterogeneity detected in both groups. Experimental N deposition significantly decreased the richness and diversity of genes involved in the depolymerization of starch (∼12%), hemicellulose (∼16%), cellulose (∼16%), chitin (∼15%), and lignin (∼16%). The decrease in richness occurred across all taxonomic groupings detected by the microarray. The compositions of genes encoding oxidoreductases, which plausibly mediate lignin decay, were responsible for much of the observed dissimilarity between actinobacterial communities under ambient and experimental N deposition. This shift in composition and decrease in richness and diversity of genes encoding enzymes that mediate the decay process has occurred in parallel with a reduction in the extent of decay and accumulation of soil organic matter. Our observations indicate that compositional changes in actinobacterial and fungal communities elicited by experimental N deposition have functional implications for the cycling and storage of carbon in forest ecosystems.

Insect Defoliators as Periodic Disturbances in Northern Forest Ecosystems

2007 ◽  
pp. 487-525 ◽  
Author(s):  
Barry J. Cooke ◽  
Vincent G. Nealis ◽  
Jacques Régnière
Keyword(s):  
Forest Ecosystems ◽  
Northern Forest ◽  
Periodic Disturbances
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