Are Fe and P availabilities involved in determining the occurrence and distribution of Calluna vulgaris (L.) Hull in semi-arid grasslands on calcareous soils?

Abstract

Calluna vulgaris (L.) Hull is primarily found on acid soils and is generally classified as a calcifuge species. Therefore, its occasional growth in semi-arid grassland on shallow calcareous soils gave rise to the question as to whether special soil conditions, deviating from the typical conditions in calcareous soils, enable this unusual occurrence. In an attempt to answer this question, we analysed selected soil factors, comparing plots where C. vulgaris was growing besides calcicole species (=CF plots) with neighbouring plots where only calcicole species were present (=CC plots). Main emphasis was placed on Fe and P availability because results from growth experiments indicate that the availability of either Fe or P to calcifuges causes calcifuge species to fail on calcareous soils. The results of our investigations do not support the hypothesis that the occurrence of C. vulgaris in semi-arid calcareous grasslands depends on higher Fe and/or P availability.Rather, its growth on carbonate-buffered soils shows that this species is not really calcifuge. Since the CF plots differ from the CC plots either by a lower inclination or by a more northerly exposition, we assume that the primary establishment and this species' distribution pattern in the investigated semi-arid grassland are not dependent on soil chemical factors, but are governed by topography and its consequences for soil humidity and drought stress.

The lime–silicate question

“…Phosphate sorption and desorption characteristics in soils are complex (Schoumans and Chardon, 2014). Availability of P for plant growth is particularly restricted in calcareous soils (Tyler, 1992), because high Ca 2þ concentrations and high pH cause the precipitation of Ca-phosphates and formation of apatites (Fühner and Runge, 2009). In acid soils, P is often bound to Al and then also inaccessible for plants.…”

Calluna vulgaris as a Valuable Source of Bioactive Compounds: Exploring Its Phytochemical Profile, Biological Activities and Apitherapeutic Potential

“…Described as an oligotrophic, calcifuge species [ 23 , 24 ], this small evergreen perennial plant with woody, flexible stalks [ 25 ] is able to survive in rigid soils (acid soils, poor in minerals) [ 26 , 27 , 28 ] and severe environmental conditions (precipitations, temperature, altitudinal zonation, etc.) [ 29 , 30 , 31 , 32 ].…”

Interactive effects of climate change and plant invasion on alpine biodiversity and ecosystem dynamics

“…Similarly, soil chemical and biotic characteristics are unlikely to limit the invasion of C. vulgaris in New Zealand at large spatial scales on either island. Soil pH across New Zealand is predominantly within the ranges of 3 -6.5, which is highly suitable for C. vulgaris (Walker et al 2007, Fühner andRunge 2009).…”

“…Further, it forms facultative (Bannister and Norton 1974) ericoid mycorrhizas with generalist fungal partners (Johansson 2001). Finally, although C. vulgaris prefers acidic soils, its edaphic requirements are broad relative to many plant species (Walker et al 2007, Fühner andRunge 2009). C. vulgaris produces large numbers of small (5-8mm length), bell-shaped, tetramerous flowers in late summer Bannister 1995, Descamps et al 2015).…”

“…Furthermore, C. vulgaris is both wind and insect pollinated and is a generalist in its pollinator interactions (Descamps et al 2015); the pollinating fauna in New Zealand is dominated by generalists (Primack 1983). Finally, although C. vulgaris prefers acidic soils, its edaphic requirements are broad relative to many plant species (Walker et al 2007, Fühner andRunge 2009).…”