Plants on Rich-Magnesium Dolomite Barrens: A Global Phenomenon

Spontaneous Primary Succession and Vascular Plant Recovery in the Iberian Gypsum Quarries: Insights for Ecological Restoration in an EU Priority Habitat

Gypsum covers a vast area of the Iberian Peninsula, making Spain a leader in its production. Gypsum is a fundamental raw material for modern societies. However, gypsum quarries have an obvious impact on the landscape and biodiversity. Gypsum outcrops host a high percentage of endemic plants and unique vegetation, considered a priority by the EU. Restoring gypsum areas after mining is a key strategy to prevent biodiversity loss. For the implementation of restoration approaches, understanding vegetation's successional processes can be of invaluable help. To fully document the spontaneous succession in gypsum quarries and to evaluate its interest for restoration, 10 permanent plots of 20 × 50 m were proposed, with nested subplots, in which vegetation change was recorded for 13 years in Almeria (Spain). Through Species-Area Relationships (SARs), these plots' floristic changes were monitored and compared to others in which an active restoration was carried out, as well as others with natural vegetation. Furthermore, the successional pattern found was compared to those recorded in 28 quarries distributed throughout the Spanish territory. The results show that an ecological pattern of spontaneous primary auto-succession is widely recurring in Iberian gypsum quarries, which is capable of regenerating the pre-existing natural vegetation.

An in-depth investigation of cryptic taxonomic diversity in the rare endemic mustard Draba maguirei

PREMISE

Previously published evidence suggests that Draba maguirei, a mustard endemic to a few localities in the Bear River, Wellsville, and Wasatch Mountains of northern Utah, may represent a cryptic species complex rather than a single species. Conservation concerns prompted an in-depth systematic study of this taxon and its putative relatives.

METHODS

Sampling most known populations of D. maguirei s.l. (D. maguirei var. maguirei and D. maguirei var. burkei), we integrate data from geography, ecology, morphology, cytogenetics and pollen, enzyme electrophoresis, and the phylogenetic analysis of nuclear internal transcribed spacer sequences to explore potential taxonomic diversity in the species complex.

RESULTS

Draba maguirei var. burkei is shown here to be a distinct species (D. burkei) most closely related to D. globosa, rather than to D. maguirei. Within D. maguirei s.s., the northern (high elevation) and southern (low elevation) population clusters are genetically isolated and morphologically distinguishable, leading to the recognition here of the southern taxon as D. maguirei subsp. stonei.

CONCLUSIONS

Our study reveals that plants traditionally assigned to D. maguirei comprise three genetically divergent lineages (D. burkei and two newly recognized subspecies of D. maguirei), each exhibiting a different chromosome number and occupying a discrete portion of the geographic range. Although previously overlooked and underappreciated taxonomically, the three taxa are morphologically recognizable based on the distribution and types of trichomes present on the leaves, stems, and fruit. Our clarification of the diversity and distribution of these taxa provides an improved framework for conservation efforts.

Population Genomics Study and Implications for the Conservation of Zabelia tyaihyonii Based on Genotyping-By-Sequencing

Zabelia tyaihyonii (Nakai) Hisauti and H. Hara is a perennial shrub endemic to Republic of Korea that grows naturally in only a very limited region of the dolomite areas of Gangwon-do and Chungcheongbuk-do Provinces in the Republic of Korea. Given its geographical characteristics, it is more vulnerable than more widely distributed species. Despite the need for comprehensive information to support conservation, population genetic information for this species is very scarce. In this study, we analyzed the genetic diversity and population structure of 94 individuals from six populations of Z. tyaihyonii using a genotyping-by-sequencing (GBS) approach to provide important information for proper conservation and management. Our results, based on 3088 single nucleotide polymorphisms (SNPs), showed a mean expected heterozygosity (He) of 0.233, no sign of within-population inbreeding (G_IS that was close to or even below zero in all populations), and a high level of genetic differentiation (F_ST = 0.170). Analysis of molecular variance (AMOVA) indicated that the principal molecular variance existed within populations (84.5%) rather than among populations (17.0%). We suggested that six management units were proposed for conservation considering Bayesian structure analysis and phylogenetic analysis, and given the various current situations faced by Z. tyaihyonii, it is believed that not only the in situ conservation but also the ex situ conservation should be considered.

Gypsum endemics accumulate excess nutrients in leaves as a potential constitutive strategy to grow in grazed extreme soils

Extreme soils often have mineral nutrient imbalances compared to plant nutritional requirements and co-occur in open areas where grazers thrive. Thus, plants must respond to both constraints, which can affect nutrient concentrations in all plant organs. Gypsum soil provides an excellent model system to study adaptations to extreme soils under current grazing practices as it harbours two groups of plant species that differ in their tolerance to gypsum soils and foliar composition. However, nutrient concentrations in organs other than leaves, and their individual responses to simulated herbivory, are still unknown in gypsum plants. We studied plant biomass, root mass ratio and nutrient partitioning among different organs (leaves, stems, coarse roots, fine roots) in five gypsum endemics and five generalists cultivated in gypsum and calcareous soils and subjected to different levels of simulated browsing. Gypsum endemics tended to have higher elemental concentration in leaves, stems and coarse roots than generalist species in both soil types, whereas both groups tended to show similar high concentrations in fine roots. This behaviour was especially clear with sulphur (S), which is found in excess in gypsum soils, and which endemics accumulated in leaves as sulphate (>50% of S). Moreover, plants subjected to clipping, regardless of their affinity to gypsum, were unable to compensate for biomass losses and showed similar elemental composition to unclipped plants. The accumulation of excess mineral nutrients by endemic species in aboveground organs may be a constitutive nutritional strategy in extreme soils and is potentially playing an anti-herbivore role in grazed gypsum outcrops.