Germination success of habitat specialists from the Succulent Karoo and Renosterveld on different soil types

Schmiedel, Ute; Siemen, Svend-Erik; Dludlu, M.N.; Oldeland, Jens

doi:10.1016/j.sajb.2020.10.030

Cited by 4 publications

(6 citation statements)

References 42 publications

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“…This assumption is supported by the fact that several quartz species have been shown in recent germination experiments to be perfectly capable of germinating on soil substrates other than those of their original quartz habitats (Schmiedel et al, 2021). This means that some of the quartz species could grow in matrix habitats, but are outcompeted there probably by biotic interactions (Schmiedel et al, 2021). All tested species, even halophytes and salt‐tolerant species, including taxa of the Argyroderma genus, needed strong dilution of their original highly saline soils for successful germination (Schmiedel et al, 2021).…”

Section: Discussionmentioning

confidence: 94%

“…In our study all boundary types including Ruschia burtoniae habitats showed a high species turnover and very low nestedness values. High soil acidity can limit plant growth in a number of ways, such as by increasing the mobility of plant‐toxic elements or decreasing concentrations of ions that are fundamental for plant growth (Schmiedel et al, 2021). Although we found no significant relationship with increased beta diversity, soil salinity is also an important driver of phytogeography, which is particularly well documented for arid regions and desert ecosystems (Bui, 2013; Ward, 2016).…”

Section: Discussionmentioning

confidence: 99%

Section: Species Turnover Stronger Than Nestedness Componentmentioning

confidence: 97%

“…This means that some of the quartz species could grow in matrix habitats, but are outcompeted there probably by biotic interactions (Schmiedel et al, 2021). All tested species, even halophytes and salt-tolerant species, including taxa of the Argyroderma genus, needed strong dilution of their original highly saline soils for successful germination (Schmiedel et al, 2021). Thus, seeds of Argyroderma crateriforme might also benefit from the less saline conditions at margins of saline habitats or boundary zones (Schmiedel et al, 2015).…”

Section: Species Turnover Stronger Than Nestedness Componentmentioning

confidence: 99%

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Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands

Eibes

Oldeland

Irl

et al. 2021

J Vegetation Science

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Questions Habitat islands are often characterized by the presence of more or less sharp boundaries to adjacent matrix habitats. However, knowledge on boundaries of natural habitat islands is scarce, especially regarding patterns of beta diversity and its two underlying components: species turnover and nestedness. We therefore aim to quantify the effects of fine‐scaled and sharp boundaries of quartz islands (quartz gravel‐covered soils) on the different components of plant beta diversity and how they are linked to different soil environmental drivers. Location Knersvlakte, Western Cape, South Africa. Methods We sampled plant species richness in 56 fine‐scale transects of 6 m × 1 m plots across eight different boundary types (four quartz island to matrix, four between habitats on quartz islands). Soil depth and chemistry (pH, electrical conductivity) were analyzed for each 1 m2 plot. Differences in the two beta diversity components (turnover and nestedness) for each boundary type were tested by t tests. We used linear models to test relationships between species and environmental dissimilarity. Results All boundary types showed high beta diversity. Species turnover was the prevailing component for six boundary types, the nestedness component was only important for two boundary types. We found a significant linear increase of species dissimilarity with increasing dissimilarity in soil pH and distinct plant communities for the habitat types, but no significant increase for electrical conductivity or soil depth. Conclusions The spatial distinctiveness of the quartz islands leads to sharp boundaries, which result in high beta diversity, mainly through species turnover. This reflects the high levels of diversification and adaptation of the local plant communities. Nestedness occurred at two boundaries to the matrix, indicating that the latter does not necessarily represent an impermeable boundary for all species of the respective ecosystem. Studying diversity patterns across boundaries contributes to the question of applicability of island biogeography theory to habitat islands.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Species Turnover Stronger Than Nestedness Componentmentioning

confidence: 97%

Section: Species Turnover Stronger Than Nestedness Componentmentioning

confidence: 99%

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Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands

Eibes

Oldeland

Irl

et al. 2021

J Vegetation Science

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“…the flora inhabiting stressful edaphic conditions, adapted to the high concentration of heavy metals in soils (Chiarucci and Baker, 2007), wild plant life in serpentine soils with low calcium: magnesium ratio (Brady et al, 2005), halophyllous flora adapted to saline soils (Flowers and Colmer, 2015) and gypsophyllous flora adapted to high gypsum content soils (IUSS, 2007). Specialized taxa are restricted to the special habitats not because they are dependent on the respective growing conditions but because of their inability to compete on other, more benign soils (Schmiedel et al, 2021).…”

Section: Germination Of San Ignacio Seeds In Two Sites and Two Soilsmentioning

confidence: 99%

Seed germination of Opuntia dejecta, a non-desert cactus native to Central America

Matus

Perroni

Virgen

et al. 2022

J PROF ASSOC CACTUS

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Opuntia species from arid and semiarid environments have dormant seeds. The objective of this study was to evaluate how the soil influences seed germination of the cactus O. dejecta. We hypothesized that O. dejecta seeds in the basaltic rocky soil will show lower seed germination than seeds in a site with alluvial soil from the coastal plain. An experiment of partial reciprocal transplant was performed, placing seeds from basaltic soil (San Ignacio population) in pots containing alluvial soil from Puente Nacional population and in slabs from basaltic soil, and placing them on two greenhouses, in San Ignacio population and Puente Nacional population. We found that seed germination (%) was lower in San Ignacio site (with basaltic soil) than in Puente Nacional site (with alluvial soil), and that alluvial soil showed higher seed germination than basaltic soil, as well as higher seed germination in Puente Nacional than in San Ignacio. The results suggest that seed dormancy for the population situated in the rocky condition is a trait locally adapted, and the basaltic soil can be considered as a selection factor.

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Do phylogenetic community metrics reveal the South African quartz fields as terrestrial-habitat islands?

Zhigila,

Elliott,

Schmiedel

et al. 2024

Annals of Botany

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Background and aims The quartz fields of the Greater Cape Floristic Region (GCFR) are arid and island-like special habitats, hosting about 142 habitat-specialized plant species of which 81% are local endemics, characterized by a rapid turnover of species between and among sites. We use several phylogenetic community metrics to i) examine species diversity and phylogenetic structure within and among quartz fields; ii) investigate whether quartz field specialists are evolutionarily drawn from local species pools, while the alternative hypothesis posits that there is no significant evolutionary connection between quartz field specialists and the local species pools; and iii) determine whether there is an association between certain traits and the presence of species in quartz fields. Methods We sampled and developed dated phylogenies for six species-rich angiosperm families (Aizoaceae, Asteraceae, Crassulaceae, Cyperaceae, Fabaceae and Santalaceae) represented in the quartz field floras of southern Africa. Specifically, we focused on the flora of three quartz field regions in South Africa (Knersvlakte, Little Karoo and Overberg) and their surrounding species pools to address our research questions, scoring traits associated with harsh environments. Key results We found that the Overberg and Little Karoo had the highest level of species overlap for families Aizoaceae and Fabaceae, while the Knersvlakte and the Overberg had the highest species overlap for families Asteraceae, Crassulaceae, and Santalaceae. Although our phylogenetic community structure and trait analyses showed no clear patterns, relatively low pairwise phylogenetic distances between specialists and their local species pools for Aizoaceae and Fabaceae suggest that quartz species could be evolutionarily drawn from their surrounding areas, with phylogenetic overdispersion in Knersvlakte and Little Karoo for Aizoaceae and Crassulaceae. Conclusions Despite their proximity to one another within the GCFR, the studied areas differ in their species pools and the phylogenetic structure of their specialists. Our work provides further justification for increased conservation focus of these unique habitats under future scenarios of global change.

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Germination success of habitat specialists from the Succulent Karoo and Renosterveld on different soil types

Cited by 4 publications

References 42 publications

Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands

Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands

Seed germination of Opuntia dejecta, a non-desert cactus native to Central America

Do phylogenetic community metrics reveal the South African quartz fields as terrestrial-habitat islands?

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