Occurrence of non-mycorrhizal plant species in south Swedish rocky habitats is related to exchangeable soil phosphate

1 Plant species that do not typically form mycorrhiza are most likely to be successful under conditions where mycorrhizal fungi are not important for plant coexistence or where the costs of symbiosis outweigh the benefits. The relative occurrence of non-mycorrhizal species was investigated in relationship to exchangeable soil P in herbaceous vegetation, where arbuscular mycorrhizal (AM) associations are generally common. We investigated a total of 439 sites in rocky habitats with sparse vegetation and 110 meadows with dense vegetation. 2 In both rocky habitats and meadows, soil pH was inversely related to exchangeable P. In rocky habitats plant species richness increased greatly between pH 3 and 5 and was also inversely related to P. 3 Plant communities in rocky habitats contained a relatively larger proportion of non-mycorrhizal species than those in meadows. More non-mycorrhizal species occurred at high soil P in the rocky habitats, but no such relation was found in meadows. 4 Non-mycorrhizal species in rocky habitats were most common at low soil pH (high P availability). Plant species that thrived at extreme soil pH were often non-mycorrhizal. 5 The occurrence of fewer non-mycorrhizal plants in meadows than in rocky habitats supports the hypothesis that AM associations are more important in ecosystems with intense competition among plants. In rocky habitats, where abiotic stress may restrict photosynthesis more than nutrient limitation does, it is adaptive for plant species to utilize strategies other than mycorrhiza, particularly at low pH sites where P availability is likely to be adequate

The ground beetle fauna (Coleoptera:Carabidae) of abandoned fields, as related to plant cover, previous management and succession stage

This study describes differences in species richness, diversity and composition of Carabidae in gradients from recently abandoned, non-grazed fields over stages of overgrowth into forest on formerly agricultural land in a large, sandy outwash plain, south Sweden. Totally 80 pitfall traps, (4 succession stages, each represented by 4 sites; 5 traps per site) installed on 29 March 2006 were emptied continuously until 1 November. Succession stages were: 7–10 y old fallows after cereals with thin and low vegetation of small perennial and annual herbs (Ia), 7–10 y old fallows abandoned as lay with a rich plant cover of broad-leaved grasses and herbs (Ib), 20–25 y old fallows with a shrub layer of colonising pine and narrow-leaved grasses (II), and ca 80 y old pine stands planted on originally cultivated ground with a rich shrub layer but lacking herbaceous plants (III). A total of 14,068 individuals of 71 carabid species were captured. Species richness was highest in stage Ib, whereas Shannon species diversity was highest in Ia. Both species richness and diversity were lowest in III, sites II being intermediate. Total number of individuals captured site−1 was low in III, being highest in Ib. Mean body weight and total dry mass of species, however, increased with succession stage. Amara and Harpalus species were most common in Ia but important also in Ib, with large differences in species composition between the two stages. These genera were almost lacking in III, where Carabus spp. and Pterostichus niger dominated. The share of Calathus was highest in II, where C. fuscipes played a dominating role. P. versicolor dominated in Ib, whereas P. lepidus was quite common in all non-forest stages. Duration and intensity of capturing activity necessary to find most species of the sites are discussed. Many scarce or rare species in south Scandinavia were captured, mainly in Ib. Abandoned non-grazed fields are important hibernating and breeding refuges for many carabids. Using extensive and non-expensive management this ought to be considered as an additional alternative in environment conservation policy, which now usually recommends economically subsidised grazing on set-aside land

Effects of sample pretreatment and sequential fractionation by centrifuge drainage on concentrations of minerals in a calcareous soil solution

Soil solution is the direct source of mineral nutrients to vascular plants. Soil solutions of sieved samples at water-holding capacity of a seminatural calcareous soil, never cultivated or treated by fertilizers, were collected by sequential centrifugation at 24-18,900 X g relative centrifugal force (RCF), followed by ultrafiltration (0.2 mu m), and analysed for Al, Ca, Fe, K, Mg, Mn, Mo, Na, P, S, Si and pH. Soil solution held by weak forces (low RCF applied) had higher concentrations of base cations, Fe, and Si than soil solutions obtained at higher RCF. Opposite relationships were measured for P-TOT, molybdate-reactive P and Mo, whereas concentrations of Mn and S did not vary much according to RCF level. A comparison between centrifugation of soil cores at undisturbed stratification and mixed samples uncovered no great differences in soil solution pH or concentrations of major constituents, though concentrations of Ca, Si and S were 10-20% lower in solution from undisturbed cores. Possible mechanisms accounting for the observations are discussed. (C) 2000 Elsevier Science B.V. All rights reserved

Vertical distribution of major, minor, and rare elements in a Haplic Podzol

Total and 0.2 M HCl-soluble concentrations of 44 mineral elements were studied in four profiles (0-110 cm) of a Haplic Podzol, developed from a 13,000-14,000-year-old quartzite-gneiss moraine deposit in south Sweden. Depending on element and soil fraction of the element considered, concentration maxima occurred in different horizons in the soil. The E horizon was impoverished in HCl-soluble fractions of nearly all and of total contents of most elements. Most alkali (sodium, potassium, rubidium, and caesium), alkaline-earth (magnesium, calcium, strontium, and barium), and several divalent transition metals (vanadium, cobalt, nickel, zinc, cadmium, mercury, and lead) had their HCl-soluble concentration peaks in the topsoil (01 or 02 horizons, rich in organic matter), iron and gallium in the B1 horizon, aluminium together with chromium, lithium, beryllium, scandium, silicon, thorium, zirconium, and molybdenum in the B2 horizon. HCl-soluble lanthanum, yttrium, and the lanthanides (cerium, dysprosium, gadolinium, neodymium, praseodymium, samarium, thulium, and ytterbium) peaked further down in the soil. Factor (PCA) analysis (all samples and horizons considered in the HCl extraction) arranged the elements in three groups. One group was composed of the rare-earth elements but also included several less heavy transition metals as well as phosphorus, boron, and aluminium. A second group, also containing organic carbon, comprised most alkali and alkaline-earth elements but also heavy metals such as nickel, copper, lead, zinc, cadmium, and mercury. Iron and gallium were discerned as a third group in the PCA analysis. Relative budget estimates based on total amounts per unit soil volume indicated that the greatest losses since deglaciation from the E+B horizons had occurred of alkaline-earths, lanthanides, uranium, and some divalent transition metals (cadmium, cobalt, and zinc). Accumulation in the 01 and 02 horizons, however, had compensated for the losses from the mineral soil of particularly cadmium and lead, to a large extent elements originating from atmospheric deposition of long-distance transported pollutants

Differences in abundance, species richness, and body size of ground beetles (Coleoptera: Carabidae) between beech (Fagus sylvatica L.) forests on Podzol and Cambisol

Ten forest sites with a tree layer of almost pure beech in southern-central Scania, south Sweden, were studied. They were all located in the interior of large forest stands. Five of the stands were developed on mor Podzols with scanty or almost no ground layer vegetation. The other five sites were located on mull Cambisols with a rich ground layer of many vascular plant species and a shrub layer of varying density. In total, 42 carabid beetle species and 9260 individuals were captured with pitfall traps (15 per site, diameter 87 mm) during 12 weeks in April, July and September 2007. Composition of the carabid fauna differed considerably between the two types of sites. In the Cambisol sites 39 carabid species were found, compared to only 21 species in the Cambisol sites. Mean carabid species richness per site differed significantly between Cambisol and Podzol sites (n = 20.4 and 13.2, respectively). The difference was wholly due to a lower number of small carabid species (mean body length 50%) of the carabid beetle variability compared to the three other variables. Carabus glabratus and Pterostichus oblongopunctatus were almost exclusively found on Podzol. Carabus coriaceus, Pterostichus melanarius and in particular Carabus nemoralis were more abundant on Cambisol, whereas Carabus hortensis and Pterostichus niger were almost ubiquitous and attained the highest total numbers. There was no significant difference between Podzol and Cambisol sites in the total number of carabid individuals captured. C. coriaceus, C. hortensis, and Carabus violaceus, species that were abundant enough in all sites for a comparison, had significantly larger mean body sizes in the Podzol than in the Cambisol sites, a finding valid for both sexes. There were more males than females of C. coriaceus, C. violaceus, and C. nemoralis in the catches, whereas sex distribution of C. hortensis was equal. Possible explanations for the findings are differences in microclimate and food web characteristics related to differences between Podzols and Cambisols in understorey vegetation and soil or litter properties. (C) 2008 Elsevier B.V. All rights reserved

Ionic charge, radius, and potential control root/soil concentration ratios of fifty cationic elements in the organic horizon of a beech (Fagus sylvatica) forest podzol

The root/organic soil concentration ratio; R/S) of 50 cationic mineral elements was related to their ionic properties, including ionic radius (r), ionic charge (z), and ionic potential (z/r or z(2)/r). The materials studied were ectomycorrhizal beech (Fagus sylvatica L.) roots and their almost purely organic soil substrate, the O-horizon (mor; raw humus) of a Podzol in South Sweden, developed in a site which has been untouched by forestry or other mechanical disturbance since at least 50 years and located in an area with no local sources of pollution. Elements determined by ICP-AES were aluminium, barium, calcium, iron, potassium, magnesium, manganese, sodium and strontium. Determined by ICP-MS were silver, beryllium, bismuth, cadmium, cerium, cobalt, chromium, caesium, copper, dysprosium, erbium, europium, gallium, gadolinium, hafnium, mercury, holmium, indium, lanthanum, lithium, lutetium, niobium, neodymium, nickel, lead, praseodymium, rubidium, scandium, samarium, tin, terbium, thorium, titanium, thallium, thulium, uranium, vanadium, yttrium, ytterbium, zinc and zirconium. The R/S ratios were most clearly related to the ionic potential of the cationic elements studied, which accounted for approximately 60% of the variability in R/S among elements. The ionic charge of an element was more important than the ionic radius. Elements with high ionic charge had low R/S ratios and vice versa. No clear differences in R/S between essential and non-essential plant nutrients were observed, especially when ions of similar charge were compared

Comparisons of the weevil fauna (Curculionidae, Apionidae, Bruchidae) of fifteen legume hosts (Fabaceae) in South Sweden.

The legume host preference of species belonging to Curculionidae, Apionidae, and Bruchidae was studied in the province of Scania, South Sweden during 2010–2015. It was suggested that significant differences existed between host preferences reported from other parts of Europe and South Sweden. In total, 375 pure stands of 15 legume species (Fabaceae), 25 stands of each species, were carefully searched, each stand for 15 min., using a scoop net. A total of 68 species belonging to Curculionidae, Apionidae, and Bruchidae with known or suspected preference for legumes were found. Species with <10 individuals in the material as a whole were excluded from statistical analysis, leaving 44 species of these groups to be considered. Correspondence Analysis (CA) performed on plant-weevil species relationships closely reflected the phylogenetic relationships of the host plants and demonstrated that most weevils were distinctly related to one single legume species, or to a few species phylogenetically closely related. Comparisons with information from Central Europe, the British Isles, and Denmark showed that the host preferences for legume genera documented in Scania were often similar to those observed elsewhere, but that considerable differences existed within the same host genus, particularly in Trifolium