State of the world’s plants and fungi 2020

Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity

In vitro decomposition of Sphagnum-derived acrotelm and mesotelm peat by indigenous and alien basidiomycetous fungi

Northern peatlands have accumulated significant quantities of peat, and it has been predicted that rates of peat decomposition may increase due to climate warming. In peatlands, organic matter decomposition in the acrotelm is accomplished primarily by fungi that act differentially through time on various peat constituents. After four months of decomposition in vitro, I show a distinct microbiological limitation to the decomposition of Sphagnum-derived peat (mean mass losses of 1.1–7.1 %) by indigenous and alien basidiomycetous fungi of both acrotelm and mesotelm peat (the mesotelm is the lower part of the acrotelm sensu lato, in which conditions fluctuate between oxic and anoxic). Neither acrotelm nor mesotelm Sphagnum peat can be degraded effectively by many fungi (mean mass losses of 2.7 % and 4.3 % for acrotelm and mesotelm peat, respectively), including the ubiquitous wood decomposing basidiomycetes known to decompose some of nature’s most complex polymers. Peatland basidiomycetes caused significantly greater mass losses of acrotelm and mesotelm peat than wood decay basidiomycetes (mean mass losses of 5.7 % and 1.4 %, respectively). Brown rot fungi caused significantly greater mass losses to acrotelm and mesotelm peat than white rot fungi and non-wood-decay fungi (mean mass losses of 10.1 %, 1.7 %, and 2.3 %, respectively). Rates of peat decomposition may not increase to the extent previously predicted, and peatlands may not necessarily be long-term sources of CO2 in response to a warming climate

Communities of larger fungi of ombrotrophic bogs in West Siberia

Bogs are common ecosystems in the Taiga of West Siberia. Little is known about mycological diversity in these important ecosystems. This article summarises the results of a two-year study of the macrofungi in two bogs near the town of Khanty-Mansiysk. Sporocarps were collected in 20 plots (about 300 m2) established in Mukhrino Bog as well as during random walks in Mukhrino Bog and Chistoe Bog in the late summer–autumn of 2012 and 2013. The plots were established in two common bog habitats representing the Ledo-Sphagnetum fusci (LS) and Scheuchzerio palustris-Sphagnetum cuspidati (SS) plant community associations. A total of 59 distinct fungal taxa were collected from the two bogs, with the LS association having a higher species richness and diversity than the SS association (50 taxa vs. 16 taxa and 30–40 taxa per 1000 m2 vs. 6–10 taxa per 1000 m2, respectively). Each of the two plant community associations has its own characteristic fungal taxa, with the LS association having 13 characteristic taxa and the SS association having five. Nearly two thirds of the fungal taxa are saprotrophic, mainly of Sphagnum spp., while others are mycorrhizal, mainly with Pinus spp. Most taxa were collected fewer than ten times during the study period and, hence, are considered rare and may need to be recognised for conservation programmes in this region

Plant biomass and production and CO2 exchange in an ombrotrophic bog

Summary Above-ground biomass was measured at bog hummock, bog hollow and poor-fen sites in Mer Bleue, a large, raised ombrotrophic bog near Ottawa, Ont., Canada. The average above-ground biomass was 587 g m−2 in the bog, composed mainly of shrubs and Sphagnum capitula. In the poor fen, the average biomass was 317 g m−2, comprising mainly sedges and herbs and Sphagnum capitula. Vascular plant above-ground biomass was greater where the water table was lower, with a similar but weaker relationship for Sphagnum capitula and vascular leaf biomass. Below-ground biomass averaged 2400 g m−2 at the bog hummock site, of which 300 g m−2 was fine roots (\u3c 2 mm diameter), compared with 1400 g m−2 in hollows (fine roots 450 g m−2) and 1200 g m−2 at the poor-fen site. Net Ecosystem Exchange (NEE) of CO2 was measured in chambers and used to derive ecosystem respiration and photosynthesis. Under high light flux (PAR of 1500 µmol m−2 s−1), NEE ranged across sites from 0.08 to 0.22 mg m−2 s−1 (a positive value indicates ecosystem uptake) in the spring and summer, but fell to –0.01 to –0.13 mg m−2 s−1 (i.e. a release of CO2) during a late-summer dry period. There was a general agreement between a combination of literature estimates of photosynthetic capacity for shrubs and mosses and measured biomass and summer-time CO2 uptake determined by the eddy covariance technique within a bog footprint (0.40 and 0.35–0.40 mg m−2 s−1, respectively). Gross photosynthesis was estimated to be about 530 g m−2 year−1, total respiration 460 g m−2 year−1, and export of DOC, DIC and CH4 10 g m−2 year−1, leaving an annual C sequestration rate of 60 g m−2 year−1. Root production and decomposition are important parts of the C budget of the bog. Root C production was estimated to be 161–176 g m−2 year−1, resulting in fractional turnover rates of 0.2 and 1 year−1 for total and fine roots, respectively

State of the World’s Plants and Fungi

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