scholarly journals The epidemiology and small-scale spatial heterogeneity of urinary schistosomiasis in Lusaka province, Zambia

2008 ◽  
Vol 3 (1) ◽  
pp. 57 ◽  
Author(s):  
Christopher Simoonga ◽  
Lawrence N. Kazembe ◽  
Thomas K. Kristensen ◽  
Annette Olsen ◽  
Chris C. Appleton ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Small Scale ◽  
Urinary Schistosomiasis ◽  
Lusaka Province

Effects of sediment nutrients and depth on small-scale spatial heterogeneity of submersed macrophyte communities in Lake Pleasant, Pennsylvania

2004 ◽  
Vol 61 (8) ◽  
pp. 1493-1502 ◽  
Author(s):  
R K Johnson ◽  
M L Ostrofsky
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Spatial Heterogeneity ◽  
Environmental Gradients ◽  
Small Scale ◽  
Sediment Characteristics ◽  
Available Nitrogen ◽  
Total N ◽  
Available N ◽  
Prevailing Paradigm

Sediment concentrations of total and available nitrogen (N), phosphorus (P), and potassium (K) and organic matter from the littoral zone of Lake Pleasant, Pennsylvania, were highly variable. Only organic matter and total N were correlated with depth, however. This result suggests the existence of more complex environmental gradients than the prevailing paradigm of monotonic changes in sediment characteristics with increasing depth. The spatial heterogeneity of submersed aquatic plant communities was significantly correlated with depth, and available N and P. Canonical correspondence analysis demonstrated that these three factors explained 38% of the variance in community structure. Other sediment characteristics (available K, organic matter, and total N, P and K) were not significant by themselves, but all variables combined explained 63% of community-structure variance. Cluster analysis identified species or groups of species typical of endpoints on the depth versus nutrient axes. Myriophyllum exalbescens was typical of deep sites with relatively nutrient-rich sediments, whereas deep nutrient-poor sites were dominated by Vallisneria americana and Megalodonta beckii. Shallow nutrient-rich sites were dominated by several species of Potamogeton and Elodea canadensis, and shallow nutrient-poor sites were dominated by Heteranthera dubia and Najas flexilis. These results demonstrate the importance of sediment characteristics in determining macrophytes' community structure within lakes.

Variation in small-scale spatial heterogeneity of soil properties and vegetation with different land use in semiarid grassland ecosystem

2008 ◽  
Vol 310 (1-2) ◽  
pp. 103-112 ◽  
Author(s):  
Zhiyong Zhou ◽  
Osbert Jianxin Sun ◽  
Zhongkui Luo ◽  
Hongmei Jin ◽  
Quansheng Chen ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Heterogeneity ◽  
Soil Properties ◽  
Small Scale ◽  
Grassland Ecosystem ◽  
Semiarid Grassland

scholarly journals Small-scale spatial heterogeneity and seasonal variation in a population of a cave-dwelling Mediterranean mysid

1996 ◽  
Vol 18 (5) ◽  
pp. 659-671 ◽  
Author(s):  
Marta Ribes ◽  
Rafel Coma ◽  
Mikel Zabala ◽  
Josep-Maria Gili
Keyword(s):  
Seasonal Variation ◽  
Spatial Heterogeneity ◽  
Small Scale

scholarly journals Toward improved parameterization of a macro-scale hydrologic model in a discontinuous permafrost boreal forest ecosystem

2017 ◽  
Author(s):  
Abraham Endalamaw ◽  
W. Robert Bolton ◽  
Jessica M. Young-Robertson ◽  
Don Morton ◽  
Laryy Hinzman ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Vegetation Cover ◽  
Large Scale ◽  
Small Scale ◽  
Hydrological Models ◽  
Landscape Model ◽  
Coarse Resolution ◽  
Fine Resolution ◽  
Resolution Dataset ◽  
Meso Scale

Abstract. Modeling hydrological processes in the Alaskan sub-arctic is challenging because of the extreme spatial heterogeneity in soil properties and vegetation communities. However, modeling and predicting hydrological processes is critical in this region due to its vulnerability to the effects of climate change. Coarse spatial resolution datasets used in land surface modeling poised a new challenge in simulating the spatially distributed and basin integrated processes since these datasets do not adequately represent the small-scale hydrologic, thermal and ecological heterogeneity. The goal of this study is to improve the prediction capacity of meso-scale to large-scale hydrological models by introducing a small-scale parameterization scheme, which better represents the spatial heterogeneity of soil properties and vegetation cover in the Alaskan sub-arctic. The small-scale parameterization schemes are derived from observations and fine resolution landscape modeling in the two contrasting sub-basins of the Caribou Poker Creek Research Watershed (CPCRW) in Interior Alaska: one nearly permafrost-free (LowP) and one that is permafrost-dominated (HighP). The fine resolution landscape model used in the small-scale parameterization scheme is derived from the watershed topography. We found that observed soil thermal and hydraulic properties – including the distribution of permafrost and vegetation cover heterogeneity – are better represented in the fine resolution landscape model than the coarse resolution datasets. Parameters derived from coarse resolution dataset and from the fine resolution landscape model are implemented into the Variable Infiltration Capacity (VIC) meso-scale hydrological model to simulate runoff, evapotranspiration (ET) and soil moisture in the two sub-basins of the CPCRW. Simulated hydrographs based on the small-scale parameterization capture most of the peak and low flows with similar accuracy in both sub-basins compared to the parameterization based on coarse resolution dataset. On average, small-scale parameterization improves the total runoff simulation approximately by up to 50 % in the LowP sub-basin and 10 % in the HighP sub-basin from the large-scale parameterization. This study shows that the proposed small-scale landscape model can be used to improve the performance of meso-scale hydrological models in the Alaskan sub-arctic watersheds.

The influence of tree species on small scale spatial heterogeneity of soil respiration in a temperate mixed forest

2017 ◽  
Vol 590-591 ◽  
pp. 242-248 ◽  
Author(s):  
Weibin Li ◽  
Zhen Bai ◽  
Changjie Jin ◽  
Xinzhong Zhang ◽  
Dexin Guan ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Spatial Heterogeneity ◽  
Tree Species ◽  
Mixed Forest ◽  
Small Scale ◽  
Temperate Mixed Forest
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