Changes in vegetation types and Ellenberg indicator values after 65 years of fertilizer application in the Rengen Grassland Experiment, Germany

Abstract

Question: How does semi-natural grassland diversify after 65 years of differential application of Ca, N, P, and K fertilizers? Is fertilizer application adequately reflected by the Ellenberg indicator values (EIVs)?Location: Eifel Mountains, West Germany. Methods:The Rengen Grassland Experiment (RGE) was established in an oligotrophic grassland in 1941. Six fertilizer treatments (Ca, CaN, CaNP, CaNP-KCl, CaNP-K 2 SO 4 , and unfertilized control) were applied annually in five complete randomized blocks. Species composition of experimental plots was sampled in 2006 and compared with constancy tables representing grassland types in a phytosociological monograph of a wider area. Each plot was matched to the most similar community type using the Associa method. Mean EIVs were calculated for each treatment. Results:The control plots supported oligotrophic Nardus grassland of the Polygalo-Nardetum association (Violion caninae alliance). Vegetation in the Ca and CaN treatments mostly resembled montane meadow of GeranioTrisetetum (Polygono-Trisetion). Transitional types between Poo-Trisetetum and Arrhenatheretum (both from the Arrhenatherion alliance) developed in the CaNP treatment. In the CaNP-KCl and CaNP-K 2 SO 4 treatments, vegetation corresponded to the mesotrophic Arrhenatheretum meadow. Major discontinuity in species composition was found between control, Ca, and CaN treatments, and all treatments with P application. EIVs for both nutrients and soil reaction were considerably higher in P treatments than in Ca and CaN treatments. Surprisingly, the control plots had the lowest EIVs for continentality and moisture, although these factors had not been manipulated in the experiment.Conclusions: Long-term fertilizer application can create different plant communities belonging to different phytosociological alliances and classes, even within a distance of a few meters. Due to their correlated nature, EIVs can erroneously indicate changes in factors that actually did not change, but co-varied with factors that did change. In P-limited ecosystems, EIVs for nutrients may indicate availability of P rather than N.

Effects of cattle slurry application on plant species composition of moderately moist Arrhenatherion grassland

“…In general, reducing availability of soil nutrients is expected to increase plant species richness according to 'hump-back' model produced by Grime (2001) which shows species richness peaks at a moderate level of nutrient availability. The reasonable application of fertilizers can even increase plant species diversity in species-poor grassland with low productivity as was reported by Chytrý et al (2009) in the case of Arrhenatheretum meadows on oligotrophic substrates. In the Czech Republic, Arrhenatherion meadows are a typical cut grasslands with their conservation made difficult by the scarcity of research on effective management practices (Čámská and Skálová 2012).…”

Distinguishing Intensity Levels of Grassland Fertilization Using Vegetation Indices

“…In contrast, nWI remained at a high level for a longer time, indicating that water content stayed at a high level at the onset of senescence. At the time, NP(K) fertilized plots started senescing, all four VIs in the Ca and CaN plots increased because these plots host slow-growing species [23,24]. Such species not only increase in their biomass over a longer time-span, but also remain relatively constant in their water and chlorophyll content.…”

“…Furthermore, long-term fertilization resulted in significant differences in the floristic compositions of the communities. The vegetation in the Ca and CaN treatments mostly resemble the montane meadow of Geranio-Trisetetum (Polygono-Trisetion), whereas the CaNP plot features a transitional type between Poo-Trisetetum and Arrhenateretum (both from the Arrhenatherion alliance) [24]. In the NPK treatments, vegetation corresponded to the mesotrophic Arrhenateretum meadows [24].…”

Різноманіття Та Фітоіндикаційні Можливості Рослинного Угруповання

“…Такі взаємні кореляції між фітоіндикаційними шкалами здатні призводити до зміщених біоіндикаційних 84 оцінок (Pakeman et al, 2008). У довготривалих експериментах з внесення добрив у лучні екосистеми фітоіндикаційні оцінки континентальності та вологості змінювались, хоч вологість ґрунту та клімат змін не зазнавали (Chytrý et al, 2009). Цей ефект був результатом взаємної кореляції фітоіндикаційних шкал.…”