Quartz Islands

Island biogeography and ecology of distinct terrestrial habitat islands

The Quartz Islands project is a joint research project of Prof. Dr. Severin Irl (University of Frankfurt) and Dr. Ute Schmiedel and Dr. Jens Oldeland (both University of Hamburg). The project is funded by the German Science Foundation (DFG) for three years and started in January 2019. The project is conducted in collaboration with CapeNature. PhD thesis in this project by Pia Eibes. Short project description by the DFG: Quarzinseln

Photo: Severin Irl

Project objectives:

In this study, we use a combined approach of Remote sensing techniques, Community ecology and Island Biogeography to quantify drivers of different aspects of taxonomic and functional richness as well as endemism in a unique system of edaphic habitat islands. We identify habitat island structure, heterogeneity and diversity as well as environmental and geographic isolation based on satellite image classification and a subsequent ground truth vegetation survey. We quantify the processes and drivers at different scales (community, island, landscape) and on different levels of organization (species and functional).

Study area:

Our study area is located in the South African Succulent Karoo, a biodiversity hotspot with outstanding numbers of vascular plant species. Our archipelago-like study system of quartz fields contains high numbers of succulent dwarf shrub species, of which many are local endemics and highly adapted to a small scaled mosaic of habitats within the quartz fields.

Quartz islands flora:

Quartz islands house a unique flora of mainly Aizoaceae, Asteraceae and Crassulaceae, dominated by leaf-succulent, compact dwarf shrubs that evolved independently in different taxonomic lineages and areas that developed through convergent evolution. About 140 plant taxa in southern Africa are quartz island endemics, of which 120 species are locally endemic, partly covering an area of only a few square kilometres.

A) Diplosoma luckhoffii (Aizoaceae)

B) Mesembryanthemum holense (Aizoaceae)

C) Lachenalia splendida (Hyacinthaceae)

D) Conophytum calculus (Aizoaceae)

E) Dactylopsis digitata (Aizocaceae).

Photos by Ute Schmiedel and Pia Eibes.


Scientific publications

Oldeland, J., Eibes, P. M., Irl, S. D. H., & Schmiedel, U. (2022). Do image resolution and classifier choice impact island biogeographical parameters of terrestrial islands?Transactions in GIS, 00, 1– 19. https://doi.org/10.1111/tgis.12920

Pia M. Eibes, Jens Oldeland, Severin D.H. Irl, Alina Twerski, Nicole Kühne, Ute Schmiedel (2021). Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands. Journal of Vegetation Science, 32:e13036, DOI: https://doi.org/10.1111/jvs.13036


Scientific presentations & posters

Eibes, P.; Schmiedel, U., Oldeland, J.; Irl, S. (2021). Habitat islands and their arid “ocean”: Habitat islands in an arid “ocean”: relative importance of different spatial characteristics on plant species richness, percentage endemism and habitat specialists. GfÖ-Annual Meeting, virtual conference. 30. 08. – 01.09.2021 and AZEF, Arid Zone Ecology Forum, Annual Meeting 2021, 11.- 14. 10.2021, virtual conference

Eibes, P.; Oldeland, J.; Irl, S.; Twerski, A., Kühne, N.; Schmiedel, U. (2021). Habitat islands and their arid “ocean”: Partitioned beta diversity patterns of plants across sharp and distinct boundaries of quartz habitat islands. ECBC 2021, 22.-24.10.2021, virtual conference

Eibes, P.; Schmiedel, U.; Oldeland, J., Irl, S. (2019). Edaphic habitat islands in quartz fields of South Africa – a model system for Island Biogeography? Poster, Arid Zone Ecology Forum (AZEF), Kimberley (South Africa), October 2019 pdf-link

Eibes, P.; Schmiedel, U.; Oldeland, J., Irl, S. (2019). Edaphic habitat islands in quartz fields of South Africa – a model system for Island Biogeography? Poster, Island Biology in Saint-Denis (La Reunión, France), July 2019 pdf-link


Principle investigators