Abstract
The adaptation of plants to particular soil types has long intrigued biologists. Gypsum soils occupy large areas in many regions of the world and host a striking biological diversity, but their vegetation has been much less studied than that developing over serpentine or saline soils. Herein, we review all aspects of plant life on gypsum ecosystems, discuss the main processes driving their structure and functioning, and highlight the main conservation threats that they face. Plant communities in gypsum habitats typically show distinctive bands at very small spatial scales, which are mainly determined by topography. Plants living on gypsum soils can be classified into three categories: (i) wide gypsophiles are specialists that can penetrate the physical soil crust during early life stages and have physiological adjustments to cope with the chemical limitations imposed by gypsum soils; (ii) narrow gypsophiles are refugee plants which successfully deal with the physical soil crust and can tolerate these chemical limitations but do not show specific adaptations for this type of soils; and (iii) gypsovags are non-specialist gypsum plants that can only thrive in gypsum soils when the physical crust is absent or reduced. Their ability to survive in gypsum soils may also be mediated by below-ground interactions with soil microorganisms. Gypsophiles and gypsovags show efficient germination at low temperatures, seed and fruit heteromorphism within and among populations, and variation in seed dormancy among plants and populations. In gypsum ecosystems, spatio-temporal changes in the composition and structure of above-ground vegetation are closely related to those of the soil seed bank. Biological soil crusts (BSCs) dominated by cyanobacteria, lichens and mosses are conspicuous in gypsum environments worldwide, and are important drivers of ecosystem processes such as carbon and nitrogen cycling, water infiltration and run-off and soil stability. These organisms are also important determinants of the structure of annual plant communities living on gypsum soils. The short-distance seed dispersal of gypsophiles is responsible for the high number of very narrow endemisms typically found in gypsum outcrops, and suggests that these species are evolutionarily old taxa due to the time they need to colonize isolated gypsum outcrops by chance. Climate change and habitat fragmentation negatively affect both plants and BSCs in gypsum habitats, and are among the major threats to these ecosystems. Gypsum habitats and specialists offer the chance to advance our knowledge on restrictive soils, and are ideal models not only to test important evolutionary questions such as tolerance to low Ca/Mg proportions in soils, but also to improve the theoretical framework of community ecology and ecosystem functioning.
Original language | English (US) |
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Pages (from-to) | 1-18 |
Number of pages | 18 |
Journal | Biological Reviews |
Volume | 90 |
Issue number | 1 |
DOIs | |
State | Published - 2015 |
Bibliographical note
Publisher Copyright:© 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.
Keywords
- Community structure and dynamics
- Ecosystem functioning
- Edaphisms
- Gypsophily
- Local adaptation
- Refugee plants
- Special soils
- Specialists
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- General Agricultural and Biological Sciences