Positive long-term effect of mulching on a nutrient-poor mountain meadow, Czechia

Summary

Summary

This case study reports a 13-year management experiment on an oligotrophic mountain meadow in Šumava National Park, Czech Republic. After the end of hay-making and autumn grazing, three regimes were compared on permanent plots cut each July. Mulching left the cut biomass in place, mowing removed it, and fallow had no cutting. The site sits at 1160 m on acidic brown soils with cool, wet climate. Monitoring combined yearly vegetation surveys in nested 1 m² plots and pre-treatment biomass harvests.

Mulching maintained biomass while improving diversity and soil condition. Mean aboveground biomass averaged 319 g m⁻² under mulching, 301 g m⁻² under mowing, and 386 g m⁻² in fallow. Species richness in mulched plots increased from 11.2 to 18.6 species per m² between 1997 and 2009, with a shift from grass dominance to forb-rich swards. By year nine, soils in mulched plots showed higher pHKCl (3.8 to 4.4), organic matter (4.6–6.3%), total N (0.31–0.45%), and greater plant-available P, K, Mg and Ca.

Functional trait analyses revealed communities under mulching moved toward acquisitive strategies with higher SLA, LNC and LPC and lower LDMC, SDMC, C:N and plant height. Many trait diversities increased with mulching, although SLA diversity converged. In contrast, mowing alone tended to deplete nutrients and fallowing drove litter build-up and grass competition, both reducing diversity. Detectable ecological divergence among treatments appeared only after 5–6 years, reflecting slow responses in cold, acidic conditions. The authors conclude that annual mulching is a practical, biodiversity-friendly alternative where traditional grazing has ceased, provided site fertility remains low.

Overview
Year of issue
2025
Implementation status
Ongoing
Location of the project
Šumava National Park and Biosphere Reserve, Bohemian Forest Mts., Czech Republic. SW-facing slope.
Sponge measures implemented in the case study
Mulching
Objectives
Test whether mulching can maintain or enhance plant species and functional trait diversity and sustain biomass production in oligotrophic mountain meadows after cessation of traditional hay-making and autumn grazing.
Involved partners
Authority typeAuthority nameAuthority roleCommentsAuthority responsibility
Research institute / UniversityInstitute of Botany, Czech Academy of SciencesImplementation—Responsible
Nature parkAdministration of the Šumava National ParkOthersite access and liaisonSupporting
Research institute / UniversityUniversity of South Bohemia, Faculty of ScienceOtherfield ecology, analysisSupporting
Research institute / UniversityInstitute of Ecology, Evolution & Diversity, Goethe University FrankfurtOthertrait ecologySupporting
Research institute / UniversityInstitute of Systems Biology and Ecology, Czech Academy of SciencesOthersoil and systems ecologySupporting
Site Information
Climate Zone
Cool temperate moist
Temperature (°C)
4.80 °C
Elevation range
1160 m
Slope range
SW-facing slope, 2–8° inclination.
Vegetation class
Original vegetation acidophilous meadow dominated by Deschampsia cespitosa, Festuca rubra, Agrostis capillaris, Hypericum maculatum.
WFD Ecological status
Moderate
WFD Chemical status
Failing to achieve good
Water quality status
Soil chemistry reported later in the experiment: in mulched plots, increases by 2007 in pHKCl (≈3.8 to 4.4), organic matter (≈4.6–6.3%), total N (≈0.31–0.45%), and plant-available P, K, Mg, Ca; limited changes in mown and fallow plots.
Design and Implementation
Project scale
Micro
Project scale specifications
Micro-scale field experiment on a single meadow site. 12 ha surrounding context, experimental core 300 m × 400 m.
Project area
0.12 km² site footprint noted; vegetation and biomass measured in permanent 1 m × 1 m plots (five per treatment) with nested subplots.
Principles
1997 to 2009 continuous annual management and monitoring. Divergence among treatments became evident after 5–6 years.
Annual July defoliation under three regimes to compare biodiversity and productivity outcomes. Mulch left to decompose on site to recycle nutrients in an otherwise oligotrophic, acidic, cold-climate meadow.
Factor constraints
Cold mountain climate and acidic soils slow vegetation response and mulch decomposition, making long-term monitoring essential. Low inherent soil fertility. Gentle slopes.
Financing
Compensations
No
Policy and Governance
Policy description
Experiment conducted within Šumava National Park and Biosphere Reserve to inform biodiversity-friendly, economically acceptable alternatives to traditional hay-making plus autumn grazing.
Land ownership
Experimental management started in 1997 and ran for 13 consecutive growing seasons to 2009. Project finished (field phase complete).
Target remarks
Maintain plant species richness and functional diversity while sustaining biomass in nutrient-poor mountain meadows when traditional practices cease.
Pressure remarks
Abandonment of traditional management, nutrient depletion under mowing-only, grass domination and litter accumulation under fallowing, regional biodiversity decline in seminatural meadows.
Part of a wider plan
No
Public consultation
No
Has contractual arrangements
No
Impacts and Monitoring

Monitoring System

Monitoring parameters
Five permanent 1 m × 1 m plots per treatment with nine 0.33 m × 0.33 m subplots each; annual vegetation cover surveys from 1997–2009; annual pre-treatment biomass harvests at set July dates; soil chemistry compared early and at year 9; extensive plant trait datasets compiled from European grassland trait databases.

Maintenance

Maintenance requirements
Annual July cutting under the assigned regime for each plot. Mulch left in place on mulched plots; hay removed on mown plots; no cutting on fallow.

Impact Assessment Methodology

Biophysical impact assessment method
Ordination and constrained ordination (PCA, RDA), community-weighted means (CWM), Rao’s quadratic entropy for functional diversity (FD), beta-diversity partitioning per Jost, regression of biomass versus diversity and trait metrics.

Socio-economic Impacts

Direct benefits
Mulching maintained or enhanced plant species and functional diversity while keeping relatively high biomass production. It countered nutrient loss seen under mowing-only and avoided the diversity decline and litter build-up seen under fallowing.
Under mulching, FD for SLA decreased over time despite increases in mean SLA, indicating convergence for this trait even as other traits diverged. Fallowing led to grass dominance and litter accumulation with gradual diversity loss. Mowing-only led to gradual nutrient depletion and reduced productivity.

Biophysical impacts: Hydrology

Hydrological effects
Not assessed

Biophysical impacts: Biodiversity

Information on improved biodiversity
Species richness in mulched plots increased from 11.2 to 18.6 species per 1 m² over 13 years. Proportion of forbs rose from ~20% to ~60%, grasses declined from ~75% to ~20% in mulched plots. Functional trait shifts toward acquisitive strategies: higher LNC, LPC, SLA; lower LDMC, SDMC, C:N, and plant height. Functional diversity increased for many traits under mulching.

Biophysical impacts: Water & Soil Quality

Information on water quality overall
Mulched plots showed by year 9 increases in soil pH, organic matter, total N and exchangeable P, K, Mg, Ca; mown and fallow changed little. Mechanism attributed to mulch mineralisation and enhanced microbial activity and legumes.

Biophysical impacts: Others

Information on other biophysical impacts
Aboveground biomass averaged 319 g m⁻² in mulched, 301 g m⁻² in mown, 386 g m⁻² in fallow plots. Diversity and productivity were positively associated within treatments.
Lessons Learned
Key lessons
Mulching is a suitable, biodiversity-friendly management alternative for oligotrophic, acidic mountain meadows, promoting niche complementarity and preventing competitive exclusion. Detectable ecological divergence required 5–6 years, so short studies risk missing real trends. Management outcomes are climate and soil constrained in cold, acidic sites.
Drivers
Driver typeDriver roleComments
Balancing different objectivesMain driverNeed for economically acceptable alternatives after abandonment of traditional hay-making and grazing, and for biodiversity conservation in seminatural meadows.
Success factors
Success factor typeSuccess factor roleComments
OtherMain factorConsistent annual timing of management
Conducted assessments (incl. economic)Secondary factorlong-term monitoring, access to comprehensive trait data
Successful coordination between authoritiesMain factorcollaboration between research institutes and the national park administration
Cost effectiveness
No cost data. Ecologically, mulching provided a good compromise maintaining diversity and relatively high biomass without external fertiliser inputs.
Flexibility / Adaptability
Findings apply to low-productivity, acidic, cool mountain meadows. Authors caution that mulching can be inappropriate in productive lowland meadows due to auto-eutrophication and biodiversity loss reported elsewhere. Context-specificity is key.
Sources