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Assembly processes under severe abiotic filtering: adaptation mechanisms of weed vegetation to the gradient of soil constraints.

Nikolic N, Böcker R, Kostic-Kravljanac L, Nikolic M - PLoS ONE (2014)

Bottom Line: We analysed the multivariate response of cereal weed assemblages (including biomass and foliar analyses) to a strong man-made soil gradient (from highly calcareous to highly acidic, nutrient-poor soils) over short distances (field scale).The soil gradient favoured a substitution of calcicoles by calcifuges, and an increase in abundance of pseudometallophytes, with preferences for Atlantic climate, broad geographical distribution, hemicryptophytic life form, adapted to low-nutrient and acidic soils, with lower concentrations of Ca, and very narrow range of Cu concentrations in leaves.The trends of abundance of the different ecological groups of indicator species along the soil gradient were systematically reflected in the maintenance of leaf P concentrations, and strong homeostasis in biomass N:P ratio.

View Article: PubMed Central - PubMed

Affiliation: Institute for Multidisciplinary Research, University of Belgrade, Belgrade, Serbia.

ABSTRACT

Questions: Effects of soil on vegetation patterns are commonly obscured by other environmental factors; clear and general relationships are difficult to find. How would community assembly processes be affected by a substantial change in soil characteristics when all other relevant factors are held constant? In particular, can we identify some functional adaptations which would underpin such soil-induced vegetation response?

Location: Eastern Serbia: fields partially damaged by long-term and large-scale fluvial deposition of sulphidic waste from a Cu mine; subcontinental/submediterranean climate.

Methods: We analysed the multivariate response of cereal weed assemblages (including biomass and foliar analyses) to a strong man-made soil gradient (from highly calcareous to highly acidic, nutrient-poor soils) over short distances (field scale).

Results: The soil gradient favoured a substitution of calcicoles by calcifuges, and an increase in abundance of pseudometallophytes, with preferences for Atlantic climate, broad geographical distribution, hemicryptophytic life form, adapted to low-nutrient and acidic soils, with lower concentrations of Ca, and very narrow range of Cu concentrations in leaves. The trends of abundance of the different ecological groups of indicator species along the soil gradient were systematically reflected in the maintenance of leaf P concentrations, and strong homeostasis in biomass N:P ratio.

Conclusion: Using annual weed vegetation at the field scale as a fairly simple model, we demonstrated links between gradients in soil properties (pH, nutrient availability) and floristic composition that are normally encountered over large geographic distances. We showed that leaf nutrient status, in particular the maintenance of leaf P concentrations and strong homeostasis of biomass N:P ratio, underpinned a clear functional response of vegetation to mineral stress. These findings can help to understand assembly processes leading to unusual, novel combinations of species which are typically observed as a consequence of strong environmental filtering, as for instance on sites affected by industrial activities.

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Average leaf concentrations of the major soil polluting elements (S, Fe, Cu and Al) in the three major ecological groups of species along the induced soil gradient.Leaf Al concentrations are separately shown for two key species dominant on severely degraded soils (f). Species groups are defined by Indicator Species Analysis (see Figure 2). Average group elemental concentrations were calculated by weighting the concentrations in each species by the relative proportion of a species in group biomass per m2. Leaves were sampled when crop was at milky ripeness phase (Z71–75).
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pone-0114290-g007: Average leaf concentrations of the major soil polluting elements (S, Fe, Cu and Al) in the three major ecological groups of species along the induced soil gradient.Leaf Al concentrations are separately shown for two key species dominant on severely degraded soils (f). Species groups are defined by Indicator Species Analysis (see Figure 2). Average group elemental concentrations were calculated by weighting the concentrations in each species by the relative proportion of a species in group biomass per m2. Leaves were sampled when crop was at milky ripeness phase (Z71–75).

Mentions: The soil concentrations of mineral elements (Table 3) that were strongly correlated with the main gradients in weed vegetation (Figure 4) were differentially reflected in the foliage of weed species (Figures 7 and 8). At the weed assemblage level, the leaf concentrations of the pollutants deposited with the mining waste (S, Fe, Cu and Al) roughly reflected the increase of pollution load along the spatial transects (Figure 7), but these trends did not indicate any relation with the spatial succession of the three major groups of indicator species (see Figures 2, 3 and 5). All three ecological groups of weeds successfully maintained leaf Cu concentrations in a relatively narrow range along the soil gradient (Figure 7d). Only one species (Chenopodium botrys) consistently had a markedly elevated leaf Cu concentration (over 100 mg kg−1 DW), but it never reached an OTV>4. Moreover, the two major species adapted to the most acidified soils apparently had contrasting adaptation strategies to high extractable Al (Figure 7f). As a consequence, differences in leaf Al concentrations at the vegetation relevée level between the common weeds of a broad ecological valence (Cluster B) and weeds that strongly indicate the most severely altered soils (Cluster C) could not be detected (Figure 7e).


Assembly processes under severe abiotic filtering: adaptation mechanisms of weed vegetation to the gradient of soil constraints.

Nikolic N, Böcker R, Kostic-Kravljanac L, Nikolic M - PLoS ONE (2014)

Average leaf concentrations of the major soil polluting elements (S, Fe, Cu and Al) in the three major ecological groups of species along the induced soil gradient.Leaf Al concentrations are separately shown for two key species dominant on severely degraded soils (f). Species groups are defined by Indicator Species Analysis (see Figure 2). Average group elemental concentrations were calculated by weighting the concentrations in each species by the relative proportion of a species in group biomass per m2. Leaves were sampled when crop was at milky ripeness phase (Z71–75).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256224&req=5

pone-0114290-g007: Average leaf concentrations of the major soil polluting elements (S, Fe, Cu and Al) in the three major ecological groups of species along the induced soil gradient.Leaf Al concentrations are separately shown for two key species dominant on severely degraded soils (f). Species groups are defined by Indicator Species Analysis (see Figure 2). Average group elemental concentrations were calculated by weighting the concentrations in each species by the relative proportion of a species in group biomass per m2. Leaves were sampled when crop was at milky ripeness phase (Z71–75).
Mentions: The soil concentrations of mineral elements (Table 3) that were strongly correlated with the main gradients in weed vegetation (Figure 4) were differentially reflected in the foliage of weed species (Figures 7 and 8). At the weed assemblage level, the leaf concentrations of the pollutants deposited with the mining waste (S, Fe, Cu and Al) roughly reflected the increase of pollution load along the spatial transects (Figure 7), but these trends did not indicate any relation with the spatial succession of the three major groups of indicator species (see Figures 2, 3 and 5). All three ecological groups of weeds successfully maintained leaf Cu concentrations in a relatively narrow range along the soil gradient (Figure 7d). Only one species (Chenopodium botrys) consistently had a markedly elevated leaf Cu concentration (over 100 mg kg−1 DW), but it never reached an OTV>4. Moreover, the two major species adapted to the most acidified soils apparently had contrasting adaptation strategies to high extractable Al (Figure 7f). As a consequence, differences in leaf Al concentrations at the vegetation relevée level between the common weeds of a broad ecological valence (Cluster B) and weeds that strongly indicate the most severely altered soils (Cluster C) could not be detected (Figure 7e).

Bottom Line: We analysed the multivariate response of cereal weed assemblages (including biomass and foliar analyses) to a strong man-made soil gradient (from highly calcareous to highly acidic, nutrient-poor soils) over short distances (field scale).The soil gradient favoured a substitution of calcicoles by calcifuges, and an increase in abundance of pseudometallophytes, with preferences for Atlantic climate, broad geographical distribution, hemicryptophytic life form, adapted to low-nutrient and acidic soils, with lower concentrations of Ca, and very narrow range of Cu concentrations in leaves.The trends of abundance of the different ecological groups of indicator species along the soil gradient were systematically reflected in the maintenance of leaf P concentrations, and strong homeostasis in biomass N:P ratio.

View Article: PubMed Central - PubMed

Affiliation: Institute for Multidisciplinary Research, University of Belgrade, Belgrade, Serbia.

ABSTRACT

Questions: Effects of soil on vegetation patterns are commonly obscured by other environmental factors; clear and general relationships are difficult to find. How would community assembly processes be affected by a substantial change in soil characteristics when all other relevant factors are held constant? In particular, can we identify some functional adaptations which would underpin such soil-induced vegetation response?

Location: Eastern Serbia: fields partially damaged by long-term and large-scale fluvial deposition of sulphidic waste from a Cu mine; subcontinental/submediterranean climate.

Methods: We analysed the multivariate response of cereal weed assemblages (including biomass and foliar analyses) to a strong man-made soil gradient (from highly calcareous to highly acidic, nutrient-poor soils) over short distances (field scale).

Results: The soil gradient favoured a substitution of calcicoles by calcifuges, and an increase in abundance of pseudometallophytes, with preferences for Atlantic climate, broad geographical distribution, hemicryptophytic life form, adapted to low-nutrient and acidic soils, with lower concentrations of Ca, and very narrow range of Cu concentrations in leaves. The trends of abundance of the different ecological groups of indicator species along the soil gradient were systematically reflected in the maintenance of leaf P concentrations, and strong homeostasis in biomass N:P ratio.

Conclusion: Using annual weed vegetation at the field scale as a fairly simple model, we demonstrated links between gradients in soil properties (pH, nutrient availability) and floristic composition that are normally encountered over large geographic distances. We showed that leaf nutrient status, in particular the maintenance of leaf P concentrations and strong homeostasis of biomass N:P ratio, underpinned a clear functional response of vegetation to mineral stress. These findings can help to understand assembly processes leading to unusual, novel combinations of species which are typically observed as a consequence of strong environmental filtering, as for instance on sites affected by industrial activities.

Show MeSH
Related in: MedlinePlus