Bacterial communities in soil become sensitive to drought under intensive grazing

Abstract

Increasing climatic and anthropogenic pressures on soil ecosystems are expected to create a global patchwork of disturbance scenarios. Some regions will be strongly impacted by climate change, others by agricultural intensification, and others by both. Soil microbial communities are integral components of terrestrial ecosystems, but their responses to multiple perturbations are poorly understood. Here, we exposed soils from sustainably- or intensively-managed grasslands in an agro-silvo-pastoral oak woodland to month-long intensified drought and flood simulation treatments in a controlled mesocosm setting. We monitored the response of the bacterial communities at the end of one month as well as during the following month of recovery. The communities in sustainably-managed plots under all precipitation regimes were richer and more diverse than those in intensively-managed plots, and contained a lower proportion of rapidly-growing taxa. Soils from both land managements exhibited changes in bacterial community composition in response to flooding, but only intensively-managed soils were affected by drought. The ecologies of bacteria favored by both drought and flood point to both opportunism and stress tolerance as key traits shaping the community following disturbance. Finally, the response of several taxa (i.e. Chloracidobacteria RB41, Janthinobacterium sp.) to precipitation depended on land management, suggesting that the community itself affected individual disturbance responses. Our findings provide an in-depth view of the complexity of soil bacterial community responses to climatic and anthropogenic pressures in time, and highlight the potential of these stressors to have multiplicative effects on the soil biota.

Habitats Are More Important Than Seasons in Shaping Soil Bacterial Communities on the Qinghai-Tibetan Plateau

“…Both anthropogenic and natural factors affect the microbial communities in permafrost. Soil temperature, moisture, organic matter content and pH can influence the microbial community by directly regulating its physiological activities [ 4 , 5 ], while vegetation characteristics [ 5 ], spatiotemporal conversion [ 6 ], grazing intensity [ 7 ] and fertilizer management indirectly impact microbial communities by influencing nutrients in the soil [ 8 ]. Studies have shown that bacterial community structures vary among different habitats and months at small spatial scales due to changes in environmental conditions and ecological interactions [ 6 , 9 ].…”

Resistance–recovery trade‐off of soil microbial communities under altered rain regimes: An experimental test across European agroecosystems

“…bacteria, copiotrophs, drought, extracellular enzyme, fungi, oligotrophs, PLFA, resilience Managed grasslands are very common in agricultural landscapes (Lemaire et al, 2005), such as permanent grassland or sown grasslands included in crop rotation, with large variability of management intensity. Few studies have assessed the effect of grassland management on soil microbial community resilience (Cole et al, 2019;Jurburg, Natal-da-Luz, et al, 2017;Karlowsky, Augusti, Ingrisch, Hasibeder, et al, 2018), and it is still not clear how conventional and ecological systems might differ in their resilience capacity. Here, we used a cross-country experiment (France, Switzerland and Portugal; Figure S1) with intact monoliths brought to a common environment to test how contrasting management (conventional vs. ecological) affects soil microbial properties and their resistance and recovery to different altered rain regimes (dry, wet and intermittent wet/dry as compared to a control 'normal' level).…”

Salinization effects on coastal ecosystems: a terrestrial model ecosystem approach

“…Terrestrial model ecosystems (TME) [31] were used to assess soil salinization effects on soil communities and their potential recovery. These reproducible and controlled semi-field set-ups are accepted tools to evaluate the effects of soil contaminants and other stressors (including climate changes), as well as management practices, on soil communities [32][33][34][35][36][37]. Indeed, they consist of intact soil cores, containing the natural communities of soil fauna and flora, where long-term stability of the soil system is provided, allowing evaluation of not only the effects but also the communities' recovery potential [32,38].…”