Publications by authors named "T Martijn Bezemer"

59 Publications

Plant-Soil Feedbacks and Temporal Dynamics of Plant Diversity-Productivity Relationships.

Trends Ecol Evol 2021 Jul 20;36(7):651-661. Epub 2021 Apr 20.

Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO- KNAW), Wageningen, The Netherlands; Institute of Biology, Section Plant Ecology and Phytochemistry, Leiden University, 2300, RA, Leiden, The Netherlands.

Plant-soil feedback (PSF) and diversity-productivity relationships are important research fields to study drivers and consequences of changes in plant biodiversity. While studies suggest that positive plant diversity-productivity relationships can be explained by variation in PSF in diverse plant communities, key questions on their temporal relationships remain. Here, we discuss three processes that change PSF over time in diverse plant communities, and their effects on temporal dynamics of diversity-productivity relationships: spatial redistribution and changes in dominance of plant species; phenotypic shifts in plant traits; and dilution of soil pathogens and increase in soil mutualists. Disentangling these processes in plant diversity experiments will yield new insights into how plant diversity-productivity relationships change over time.
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http://dx.doi.org/10.1016/j.tree.2021.03.011DOI Listing
July 2021

Spatial patterns and ecological drivers of soil nematode β-diversity in natural grasslands vary among vegetation types and trophic position.

J Anim Ecol 2021 05 17;90(5):1367-1378. Epub 2021 Mar 17.

Erguna Forest-Steppe Ecotone Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.

Understanding biogeographic patterns of community assemblages is a core objective in ecology, but for soil communities these patterns are poorly understood. To understand the spatial patterns and underlying mechanisms of β-diversity in soil communities, we investigated the β-diversity of soil nematode communities along a 3,200-km transect across semi-arid and arid grasslands. Spatial turnover and nested-resultant are the two fundamental components of β-diversity, which have been attributed to various processes of community assembly. We calculated the spatial turnover and nested-resultant components of soil nematode β-diversity based on the β-partitioning framework. Distance matrices for the dissimilarity of soil nematode communities were computed using the 'Sørensen' method. We fitted negative exponential models to compare the distance decay patterns in nematode community similarity with geographic distance and plant community distance in three vegetation types (desert, desert steppe and typical steppe) and along the whole transect. Variation partitioning was used to distinguish the contribution of geographic distance and environmental variables to β-diversity and the partitioned components. Geographic distance and environmental filtering jointly drove the β-diversity patterns of nematode community, but environmental filtering explained more of the variation in β-diversity in the desert and typical steppe, whereas geographic distance was important in the desert steppe. Nematode community assembly was explained more by the spatial turnover component than by the nested-resultant component. For nematode feeding groups, the β-diversity in different vegetation types increased with geographic distance and plant community distance, but the nested-resultant component of bacterial feeders in the desert ecosystem decreased with geographic distance and plant community distance. Our findings show that spatial variation in soil nematode communities is regulated by environmental processes at the vegetation type scale, while spatial processes mainly work on the regional scale, and emphasize that the spatial patterns and drivers of nematode β-diversity differ among trophic levels. Our study provides insight into the ecological processes that maintain soil biodiversity and biogeographic patterns of soil community assemblage at large spatial scales.
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http://dx.doi.org/10.1111/1365-2656.13461DOI Listing
May 2021

Globally, plant-soil feedbacks are weak predictors of plant abundance.

Ecol Evol 2021 Feb 27;11(4):1756-1768. Epub 2021 Jan 27.

Department of Biology University of British Columbia Kelowna BC Canada.

Plant-soil feedbacks (PSFs) have been shown to strongly affect plant performance under controlled conditions, and PSFs are thought to have far reaching consequences for plant population dynamics and the structuring of plant communities. However, thus far the relationship between PSF and plant species abundance in the field is not consistent. Here, we synthesize PSF experiments from tropical forests to semiarid grasslands, and test for a positive relationship between plant abundance in the field and PSFs estimated from controlled bioassays. We meta-analyzed results from 22 PSF experiments and found an overall positive correlation (0.12 ≤   ≤ 0.32) between plant abundance in the field and PSFs across plant functional types (herbaceous and woody plants) but also variation by plant functional type. Thus, our analysis provides quantitative support that plant abundance has a general albeit weak positive relationship with PSFs across ecosystems. Overall, our results suggest that harmful soil biota tend to accumulate around and disproportionately impact species that are rare. However, data for the herbaceous species, which are most common in the literature, had no significant abundance-PSFs relationship. Therefore, we conclude that further work is needed within and across biomes, succession stages and plant types, both under controlled and field conditions, while separating PSF effects from other drivers (e.g., herbivory, competition, disturbance) of plant abundance to tease apart the role of soil biota in causing patterns of plant rarity versus commonness.
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http://dx.doi.org/10.1002/ece3.7167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882948PMC
February 2021

Microbiomes of a specialist caterpillar are consistent across different habitats but also resemble the local soil microbial communities.

Anim Microbiome 2020 Oct 7;2(1):37. Epub 2020 Oct 7.

Department of Terrestrial Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB, Wageningen, The Netherlands.

Background: Insect-associated microorganisms can provide a wide range of benefits to their host, but insect dependency on these microbes varies greatly. The origin and functionality of insect microbiomes is not well understood. Many caterpillars can harbor symbionts in their gut that impact host metabolism, nutrient uptake and pathogen protection. Despite our lack of knowledge on the ecological factors driving microbiome assemblages of wild caterpillars, they seem to be highly variable and influenced by diet and environment. Several recent studies have shown that shoot-feeding caterpillars acquire part of their microbiome from the soil. Here, we examine microbiomes of a monophagous caterpillar (Tyria jacobaeae) collected from their natural host plant (Jacobaea vulgaris) growing in three different environments: coastal dunes, natural inland grasslands and riverine grasslands, and compare the bacterial communities of the wild caterpillars to those of soil samples collected from underneath each of the host plants from which the caterpillars were collected.

Results: The microbiomes of the caterpillars were dominated by Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. Only 5% of the total bacterial diversity represented 86.2% of the total caterpillar's microbiome. Interestingly, we found a high consistency of dominant bacteria within the family Burkholderiaceae in all caterpillar samples across the three habitats. There was one amplicon sequence variant belonging to the genus Ralstonia that represented on average 53% of total community composition across all caterpillars. On average, one quarter of the caterpillar microbiome was shared with the soil.

Conclusions: We found that the monophagous caterpillars collected from fields located more than 100 km apart were all dominated by a single Ralstonia. The remainder of the bacterial communities that were present resembled the local microbial communities in the soil in which the host plant was growing. Our findings provide an example of a caterpillar that has just a few key associated bacteria, but that also contains a community of low abundant bacteria characteristic of soil communities.
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http://dx.doi.org/10.1186/s42523-020-00055-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7807420PMC
October 2020

Quantitative comparison between the rhizosphere effect of Arabidopsis thaliana and co-occurring plant species with a longer life history.

ISME J 2020 10 8;14(10):2433-2448. Epub 2020 Jul 8.

Department of Plant Sciences, Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.

As a model for genetic studies, Arabidopsis thaliana (Arabidopsis) offers great potential to unravel plant genome-related mechanisms that shape the root microbiome. However, the fugitive life history of this species might have evolved at the expense of investing in capacity to steer an extensive rhizosphere effect. To determine whether the rhizosphere effect of Arabidopsis is different from other plant species that have a less fugitive life history, we compared the root microbiome of Arabidopsis to eight other, later succession plant species from the same habitat. The study included molecular analysis of soil, rhizosphere, and endorhizosphere microbiome both from the field and from a laboratory experiment. Molecular analysis revealed that the rhizosphere effect (as quantified by the number of enriched and depleted bacterial taxa) was ~35% lower than the average of the other eight species. Nevertheless, there are numerous microbial taxa differentially abundant between soil and rhizosphere, and they represent for a large part the rhizosphere effects of the other plants. In the case of fungal taxa, the number of differentially abundant taxa in the Arabidopsis rhizosphere is 10% of the other species' average. In the plant endorhizosphere, which is generally more selective, the rhizosphere effect of Arabidopsis is comparable to other species, both for bacterial and fungal taxa. Taken together, our data imply that the rhizosphere effect of the Arabidopsis is smaller in the rhizosphere, but equal in the endorhizosphere when compared to plant species with a less fugitive life history.
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http://dx.doi.org/10.1038/s41396-020-0695-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490400PMC
October 2020