Impact of water levels on Typha spp. in a mesocosm experiment

Paludiculture is the productive use of wet or rewetted peatlands. Typha spp. is a promising paludiculture crop with usage options, including as building or insulation material. As part of the Paludi-PROGRESS project (Putting paludiculture into practice – optimization of cattail and reed cultures, project period 2022-2025) a mesocosm experiment was conducted to assess the above- and belowground biomass production and decomposition of Typha latifolia and Typha angustifolia to different water level treatments.

Using non-destructive sampling methods, we examined the annual biomass production of T. latifolia and T. angustifolia from April 2023 to April 2024 in response to either a water level gradient of -20 to +6 cm or to a drought gradient of 2 to 11 weeks. Phenospex PlantEye was used to assess the aboveground biomass production with a multi-spectral scanner. Belowground biomass production was examined with minirhizotrons and decomposition was assessed using litter bags.

At higher water levels, T. angustifolia showed higher aboveground biomass production whereas T. latifolia had higher aboveground biomass production at lower water levels. The latter also expressed higher belowground biomass production at lower water levels, whereas T. angustifolia’s belowground biomass response shifted during the vegetation period, benefitting from higher water levels until June 2023, afterwards showing higher belowground biomass production at lower water levels. Whereas both species benefit from short drought periods (2-4 weeks) with increasing belowground biomass production, longer drought periods negatively affected both species above- as well as belowground biomass production. T. angustifolia seemed to be more resilient against drought than T. latifolia. Information about the optimal water level and drought resistance of potential paludiculture crops are important information for a successful cultivation of Typha spp.