Impact of Ecosystem Management on Microbial Community Level Physiological Profiles of Postmining Forest Rehabilitation

Abstract

We investigated the impacts of forest thinning, prescribed fire, and contour ripping on community level physiological profiles (CLPP) of the soil microbial population in postmining forest rehabilitation. We hypothesized that these management practices would affect CLPP via an influence on the quality and quantity of soil organic matter. The study site was an area of Jarrah (Eucalyptus marginata Donn ex Sm.) forest rehabilitation that had been mined for bauxite 12 years previously. Three replicate plots (20 x 20 m) were established in nontreated forest and in forest thinned from 3,000-8,000 stems ha(-1) to 600-800 stems ha(-1) in April (autumn) of 2003, followed either by a prescribed fire in September (spring) of 2003 or left nonburned. Soil samples were collected in August 2004 from two soil depths (0-5 cm and 5-10 cm) and from within mounds and furrows caused by postmining contour ripping. CLPP were not affected by prescribed fire, although the soil pH and organic carbon (C), total C and total nitrogen (N) contents were greater in burned compared with nonburned plots, and the coarse and fine litter mass lower. However, CLPP were affected by forest thinning, as were fine litter mass, soil C/N ratio, and soil pH, which were all higher in thinned than nonthinned plots. Furrow soil had greater coarse and fine litter mass, and inorganic phosphorous (P), organic P, organic C, total C, total N, ammonium, microbial biomass C contents, but lower soil pH and soil C/N ratio than mound soil. Soil pH, inorganic P, organic P, organic C, total C and N, ammonium, and microbial biomass C contents also decreased with depth, whereas soil C/N ratio increased. Differences in CLPP were largely (94%) associated with the relative utilization of gluconic, malic (greater in nonthinned than thinned soil and mound than furrow soil), L-tartaric, succinic, and uric acids (greater in thinned than nonthinned, mound than furrow, and 5-10 cm than 0-5 cm soil). The relative utilization of amino acids also tended to increase with increasing soil total C and organic C contents but decreased with increasing nitrate content, whereas the opposite was true for carboxylic acids. Only 45% of the variance in CLPP was explained using a multivariate multiple regression model, but soil C and N pools and litter mass were significant predictors of CLPP. Differences in soil textural components between treatments were also correlated with CLPP; likely causes of these differences are discussed. Our results suggest that 1 year after treatment, CLPP from this mined forest ecosystem are resilient to a spring prescribed fire but not forest thinning. We conclude that differences in CLPP are likely to result from complex interactions among soil properties that mediate substrate availability, microbial nutrient demand, and microbial community composition.

Soil microbial functional diversity and biomass as affected by different thinning intensities in a Chinese fir plantation

“…The PCA showed that the microbial communities in the soil under the different treatments were well separated, indicating that the microbial communities in the different treatments were distinct. Our results are consistent with those of Cookson et al (2008), who examined the community-level physiological profiles (CLPP) of surface (0-5 cm depth) and subsurface soil (5-10 cm depth) microbial communities under thinning, prescribed fire, and contour ripping treatments in a stand dominated by Jarrah (Eucalyptus marginata Donn ex Sm.) and obtained results that also clearly distinguished the thinned and non-thinned plots.…”

“…Both Thibodeau et al (2000) and Bolat (2014) observed that thinning increased MBC and MBN, but other studies showed that MBC and MBN were decreased or unchanged after thinning (Barg and Edmonds, 1999;Giai and Boerner, 2007;Schilling et al, 1999). To date, few studies have focused on soil microbial diversity changes associated with thinning, although Cookson et al (2008) and Giai and Boerner (2007) found that thinning had a significant effect on soil functional diversity. However, few of these studies used seasonal data to study soil functional microbial diversity.…”

Spatial distribution of bacterial communities driven by multiple environmental factors in a beach wetland of the largest freshwater lake in China

“…Several studies suggest that bacterial distributions may be spatially predictable rather than random (Ettema and Wardle, 2002). Differences in environmental factors along sediment horizontal gradients largely determine bacterial composition and diversity, such as water content (Drenovsky et al, 2004; Badin et al, 2011), C and N availability (Cookson et al, 2008; Moseman-Valtierra et al, 2010; Mackelprang et al, 2011; Lin et al, 2012), temperature (Hall et al, 2008; Redmond and Valentine, 2011), pH (Lindström et al, 2005), and sediment structure characteristics (Liu et al, 2011). Despite the importance of sediment bacteria in biogeochemical cycling, the bacterial communities in the deeper layers are not well studied (Haglund et al, 2003; Luna et al, 2004); the bacterial communities of the sediment surface layers have been far better studied than those of the deeper layers (Liao et al, 2009; Schauer et al, 2010).…”

Impacts of Triclosan in Greywater on Soil Microorganisms

“…As the primary organisms involved in the decomposition and recycling of organic materials, microbial communities are the basis of soil fertility providing nutrients both directly and indirectly to higher organisms. Thus, changes in the structure or function of either the entire heterotrophic microbial community or of component microbial assemblages has the potential to profoundly impact the rest of the terrestrial ecosystem [55][56][57][58]. There is an increasing recognition of essential functions fulfilled by microorganisms involved with biogeochemical cycling, and decomposition of organic matter and pollutants soil environments.…”