General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

Abstract

Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types.

The influence of environmental variables on soil mite communities (Acari: Mesostigmata) from overgrazed grassland ecosystems – Romania

“…Similar results have been reported by other authors, concluding that a pH close to neutral is optimal for mesostigmatids (Bedano et al 2005). In contrast, some other research has found that these invertebrates prefer a lower pH, which is favourable for the development of fungi, the food source for other soil invertebrates which in turn form the prey for mesostigmatids (Chikoski et al 2006;Manu 2011a;Birkhofer et al 2012). Acidity and dominance of sandy soils (such as those described from the six grassland ecosystems in the present study) are known to contribute to low actinomycete biomass (Kooijman et al 2009;Birkhofer et al 2012).…”

“…Studies on predator mite communities from natural grassland ecosystems revealed that mites have been reported as most abundant in soils with low pH values and nitrate concentrations (Hasegawa 2001;Bedano et al 2005;Birkhofer et al 2012;Miller et al 2014). Different studies have shown the relationship between soil mesofauna and nitrate content in grasslands to be very variable, with no, weak negative, strong negative or even positive correlations, depending on land-use type (Jandl et al 2003;Lindberg & Persson 2004;Cole et al 2005;Fountain et al 2008;Birkhofer et al 2012).…”

“…Different studies have shown the relationship between soil mesofauna and nitrate content in grasslands to be very variable, with no, weak negative, strong negative or even positive correlations, depending on land-use type (Jandl et al 2003;Lindberg & Persson 2004;Cole et al 2005;Fountain et al 2008;Birkhofer et al 2012).…”

Mean age of carbon in fine roots from temperate forests and grasslands with different management

“…Given the limited amount of grazed and mowed sites in our dataset, we did not find any significant effect of these management practices on root C age. We also did not find any significant correlation with soil pH, which was surprising because we expected that soil pH would vary according to different management schemes (Falkengren-Grerup et al, 2006;Birkhofer et al, 2012).…”

No depth-dependence of fine root litter decomposition in temperate beech forest soils

“…Moreover, higher root decomposition rates in the Schorfheide-Chorin may result from a greater vertical water movement through the sand in this study region, which can increase the leaching of the soluble organic matter derived from the decomposing roots. Regional differences in the diversity of the soil biota, adapted to diverse edaphic factors including climate, soil texture and pH may also have played a role in determining the regional variability in fine root decomposition (Birkhofer et al 2012, Thoms et al 2010). …”