Biology subjects

Maestre, F.

Publications and source records attributed to Maestre, F..

4 recordsLinked to original sources

bioRxiv2020

Abiotic and biotic drivers underly short- and long-term soil respiration responses to experimental warming in a dryland ecosystem

Soil carbon losses to the atmosphere through soil respiration are expected to rise with ongoing temperature increases, but available evidence from mesic biomes suggests that such response disappears after a few years of experimental warming. However, there is lack of empirical basis for these temporal dynamics in soil respiration responses, and of the mechanisms underlying them, in drylands, which collectively form the largest biome on Earth and store 32% of the global soil organic carbon pool. We coupled data from a ten-year warming experiment in a biocrust-dominated dryland ecosystem with laboratory incubations to confront 0-2 years (short-term hereafter) vs. 8-10 years (long-term hereafter) soil respiration responses to warming. Our results showed that increased soil respiration rates with short-term warming observed in areas with high biocrust cover returned to control levels in the long-term. Warming-induced increases in soil temperature were the main driver of the short-term soil respiration responses, whereas long-term soil respiration responses to warming were primarily driven by thermal acclimation and warming-induced reductions in biocrust cover. Our results highlight the importance of evaluating short and long-term soil respiration responses to warming as a mean to reduce the uncertainty in predicting the soil carbon - climate feedback in drylands.

ecology↗

bioRxiv2019

A global survey of mycobacterial diversity in soil

Mycobacterium is a diverse bacterial genus ubiquitous in many soil and aquatic environments. Members of this genus have been associated with human and other animal diseases, including the nontuberculous mycobacteria (NTM), which are of growing relevance to public health worldwide. Although soils are often considered an important source of environmentally-acquired NTM infections, the biodiversity and ecological preferences of soil mycobacteria remain largely unexplored across contrasting climates and ecosystem types. Using a culture-independent approach by combining 16S rRNA marker gene sequencing with mycobacterial-specific hsp65 gene sequencing, we analyzed the diversity, distributions, and environmental preferences of soil-dwelling mycobacteria in 143 soil samples collected from across the globe. The surveyed soils harbored highly diverse mycobacterial communities that span the full-extent of the known mycobacterial phylogeny, with most soil mycobacteria belonging to previously undescribed lineages. While the genus Mycobacterium tended to have higher relative abundances in cool, wet, and acidic soil environments, several individual mycobacterial clades had contrasting environmental preferences. We identified the environmental preferences of many mycobacterial clades, including the clinically-relevant M. avium complex that was more commonly detected in wet and acidic soils. However, most of the soil mycobacteria detected were not closely related to known pathogens, calling into question previous assumptions about the general importance of soil as a source of NTM infections. Together this work provides novel insights into the diversity, distributions and ecological preferences of soil mycobacteria, and lays the foundation for future efforts to link mycobacterial phenotypes to their distributions. ImportanceMycobacteria are common inhabitants of soil, and while most members of the bacterial genus are innocuous, some mycobacteria can cause environmentally-acquired infections of humans and other animals. Human infections from nontuberculous mycobacteria (NTM) are increasingly prevalent worldwide, and some areas appear to be hotspots for NTM disease. While exposure to soil is frequently implicated as an important mode of NTM transmission, the diversity, distributions and ecological preferences of soil mycobacteria remain poorly understood. We analyzed 143 soils from across the globe and found that the genus Mycobacterium and lineages within the genus often exhibited predictable preferences for specific environmental conditions. Soils harbor large amounts of previously-undescribed mycobacterial diversity, and lineages that include known pathogens were rarely detected in soil. Together these findings suggest that soil is an unlikely source of many mycobacterial infections. The biogeographical patterns we documented lend insight into the ecology of this important group of soil-dwelling bacteria.

microbiology↗

bioRxiv2018

Microbial dispersal limitation to isolated soil habitats in the McMurdo Dry Valleys of Antarctica

Dispersal is a critical yet poorly understood factor underlying macroecological patterns in microbial communities. Airborne microbial transport is assumed to occupy a central role in determining dispersal outcomes and extra-range dispersal has important implications for predicting ecosystem resilience and response to environmental change. One of the most pertinent biomes in this regard is Antarctica given its geographic isolation and vulnerability to climate change and human disturbance. Here we report the first characterisation of microbial diversity in near-ground and high-altitude air above a typical Antarctic Dry Valley as well as that of underlying soil microbial communities. We found that persistent airborne inputs were unable to fully explain local soil community assembly. Comparison with airborne microbial diversity from non-polar sources suggests that strong selection occurs during atmospheric transport resulting in regionally isolated airborne inputs and highly specialized soil communities where fungi displayed greater isolation than bacteria from non-polar sources. Overall microbial communities from this isolated Antarctic ecosystem displayed limited connectivity to the global microbial pool. Our findings provide critical insights to forecast the potential outcomes for microbial communities of climate change-mediated shifts in air circulation to the Dry Valleys, the largest ice-free region of Antarctica.

microbiology↗

bioRxiv2017

The Structure Of Plant Spatial Association Networks Increases Plant Diversity In Global Drylands

AimDespite their widespread use and value to unveil the complex structure of the interactions within ecological communities and their value to assess the resilience of communities, network analyses have seldom been applied in plant communities. We aim to evaluate how plant-plant interaction networks vary in global drylands, and to assess whether network structure is related to plant diversity in these ecosystems.\n\nLocation185 dryland ecosystems from all continents except Antarctica.\n\nMethodsWe built networks using the local spatial association between all the perennial plant species present in the communities studied, and used structural equation models to evaluate the effect of abiotic factors (including geography, topography, climate and soil conditions) and network structure on plant diversity.\n\nResultsThe structure of plant networks found at most study sites (72%) was not random and presented properties representative of robust systems, such as high link density and structural balance. Moreover, network indices linked to system robustness had a positive and significant effect on plant diversity, sometimes higher that the effect of abiotic factors.\n\nMain conclusionsOur results constitute the first empirical evidence showing the existence of a common network architecture structuring terrestrial plant communities at the global scale, and provide novel evidence of the importance of the network of interactions for the maintenance of biodiversity. Furthermore, they highlight the importance of system-level approaches to explain the diversity and structure of interactions in plant communities, two major drivers of terrestrial ecosystem functioning and resilience against the likely impacts derived from global change.

ecology↗