Resilience in coastal dune grasslands: pH and soil organic matter effects on P nutrition, plant strategies, and soil communities

Abstract

2020. Resilience in coastal dune grasslands: pH and soil organic matter effects on P nutrition, plant strategies, and soil communities. Ecosphere 11(5):Abstract. Soil organic matter (SOM) and pH are key ecosystem drivers, influencing resilience to environmental change. We tested the separate effects of pH and SOM on nutrient availability, plant strategies, and soil community composition in calcareous and acidic Grey dunes (H2130) with low, intermediate, and/or high SOM, which differ in sensitivity to high atmospheric N deposition. Soil organic matter was mainly important for biomass parameters of plants, microbes, and soil animals, and for microarthropod diversity and network complexity. However, differences in pH led to fundamental differences in P availability and plant strategies, which overruled the normal soil community patterns, and influenced resilience to N deposition. In calcareous dunes with low grass-encroachment, P availability was low despite high amounts of inorganic P, due to low solubility of calcium phosphates and strong P sorption to Fe oxides at high pH. Calcareous dunes were dominated by low-competitive arbuscular mycorrhizal (AM) plants, which profit from mycorrhiza especially at low P. In acidic dunes with high grass-encroachment, P availability increased as calcium phosphates dissolved and P sorption weakened with the shift from Fe oxides to Fe-OM complexes. Weakly sorbed and colloidal P increased, and at least part of the sorbed P was organic. Acidic dunes were dominated by nonmycorrhizal (NM) plants, which increase P uptake through exudation of carboxylates and phosphatase enzymes, which release weakly sorbed P, and disintegrate labile organic P. The shifts in P availability and plant strategies also changed the soil community. Contrary to expectations, the bacterial pathway was more important in acidic than in calcareous dunes, possibly due to exudation of carboxylates and phosphatases by NM plants, which serve as bacterial food resource. Also, the fungal AM pathway was enhanced in calcareous dunes, and fungal feeders more abundant, due to the presence of AM fungi. The changes in soil communities in turn reduced expected differences in N cycling between calcareous and acidic dunes. Our results show that SOM and pH are important, but separate ecosystem drivers in Grey dunes. Differences in resilience to N deposition are mainly due to pH effects on P availability and plant strategies, which in turn overruled soil community patterns.

The Damage Caused by Decline Disease in Bayberry Plants through Changes in Soil Properties, Rhizosphere Microbial Community Structure and Metabolites

“…Furthermore, the results of this study revealed the complexity of the relationship between microbial growth and soil nutrient elements due to the fact that a differential change was observed between diseased and healthy bayberry rhizosphere soil in the contents of available soil nutrient elements, such as available nitrogen, calcium and phosphorus, as well as the magnesium content; indeed, nutritional balance may be best for microbial growth. However, the pH and organic matter have been proposed to exhibit a greater effect on microbial communities compared to the other soil parameters [31][32][33]. Therefore, the decrease in soil pH and organic matter in this study are expected to have a negative influence on microbial growth and diversity of diseased bayberry rhizosphere soil.…”

Blowout dynamics in lime‐rich and lime‐poor coastal dunes in the Netherlands

“…However, in BZ, rabbit numbers were much higher before 1996, and amounted to 26 per kilometer of road in 1989-1992. Also, the critical N load for BZ was set at 10 kg ha À1 yr À1 because of its lime-poor sand, but the dunes may be less sensitive to high N deposition due to the relatively high pH in the topsoil, which is associated with relatively low P availability (Kooijman et al, 2020(Kooijman et al, , 2021. The use of a higher critical load for BZ only slightly changed the results, but rabbit density and exceedance of the critical N load now explained 25% of the variance in total active area, instead of 3%.…”

“…The relatively low P availability in HD, AW and BZ may in turn explain why root biomass was relatively low, which may increase erodibility of the sand. High pH and low P availability to the vegetation may also have affected aeolian activity through higher food quality for rabbits, due to predominance of AM plants (Kooijman et al, 2020). It is unclear yet whether high food quality can help recover rabbits from viral diseases, but higher food quality may at least explain why rabbits are generally more abundant in lime-rich than in lime-poor dunes.…”

Invasion dynamics and potential future spread of sea spurge across Australia’s coastal dunes

“…In coastal dunes, organic carbon content and pH are primarily related to soil nutrient availability, whilst clay fraction influences soil water retention. Together, they play a key role in shaping the abundance, diversity and ecological strategy of plant species in dune ecosystems (Isermann, 2005;Kooijman et al, 2020;Vitti et al, 2020). Distance from the coast used a proxy for the sea-to-inland stress gradient that is a ubiquitous feature of coastal dune ecosystems (Carboni et al, 2011).…”