Succession in Inland Sand Ecosystems: Which Factors Determine the Occurrence of the Tall Grass Species Calamagrostis epigejos (L.) Roth and Stipa capillata L.?

Abstract

In many successional series, grass species play an important role in mid-successional stages. Using calcareous sand ecosystems in the northern upper Rhine valley (Germany) as a model, we analyzed successional trajectories and the factors that determine their direction. A 5- to 7-year study of 23 permanent plots is presented. Polar ordination revealed that succession starts with pioneer communities (dominated by Corynephorus canescens and cryptogams) and can eventually lead to relatively stable Calamagrostis epigejos or Stipa capillata tall grass stands. At some sites, Cynodon dactylon can play a major role, but we focused on the two previously mentioned species. Gradient analyses of their ecological amplitudes by means of principal components and regression analysis were carried out in order to elucidate the factors determining the successional trajectories. Soil analyses of 71 plots established significantly positive linear relations for C. epigejos with respect to total nitrogen, extractable phosphate and potassium, as well as soil moisture indicator values. C. epigejos is not able to spread if the stress factors nutrient deficiency and dryness are combined. Lower tolerance limits are presented. In contrast, S. capillata shows negative relations to phosphate, declining strongly at P contents > 20 mg kg(-1). At a moisture indicator value of around 3.2 (indicating dry sites), S. capillata reaches its optimum. S. capillata is a model for a tall grass species which, even with low nutrient levels and dry soil conditions, can be successful in mid-successional phases; but it is displaced by C. epigejos if soil moisture increases or phosphate/potassium supply is higher. Regarding a general framework, the successional phases are characterized by processes such as replacement of species, facilitation, and inhibition.

The influence of Calamagrostis epigejos expansion on the species composition and soil properties of mountain mesic meadows

“…Despite results showing a positive correlation between aboveground biomass and the amount of cumulating plant necromass which is dominated by this species with the exchangeable phosphorus and potassium concentrations in the soil, significant differences between plots along the transects occur only in the case of potassium. On the other hand, our results are in line with the observations of Süß et al [26] regarding non-degraded dry grasslands. They recorded weak positive correlations between C. epigejos coverage and soil richness in potassium and phosphorus.…”

“…Nevertheless, according to Rebele [44] and Lammerts et al [45], the availability of phosphorus and potassium facilitates the growth of C. epigejos. Süß et al [26] observed that in some cases scarcity of nutrients might prevent vast coverage by C. epigejos. The species' growth and expansion are physiologically aided by ecological succession, the corresponding increased nitrogen content in the soil, and the eutrophication of habitats as a result of increased phosphorus and potassium concentrations.…”

“…Moreover, C. epigejos is highly tolerant to abiotic stress factors [17]. Stands dominated by Calamagrostis epigejos form long-lasting stable grassland communities, what means stopping the course of succession [25,26].…”

Why are graminoid species more dominant? Trait‐mediated plant–soil feedbacks shape community composition

“…This species dominated in the two scenarios of overall PSFs but not in the two scenarios of soil biota‐mediated PSFs. Stipa species also tend to have a higher dominance after a dry year or under dry conditions in our study site and other studies as well (Cheng & Nakamura, 2006; Süß et al, 2004). This is possible because the drought may have weakened the negative soil biota‐mediated feedbacks.…”

Spatial patterns of aboveground phytogenic Si stocks in a grass-dominated catchment – results from UAS-based high-resolution remote sensing

“…The Jeffries-Matusita (J-M) distance (Kavzoglu and Mather, 2000), the divergence measure used in this study, was computed for all possible LCC pairs. A computed value of zero indicates that classes are inseparable, and a value of 1414 means total separability (Swain and Davis, 1978).…”