Strategies in Mediterranean grassland annuals in relation to stress and disturbance

Abstract

Abstract. Morphological (size and shape) and functional (growth, reproduction and phenology) attributes are used to characterize 42 annual species of Mediterranean grasslands according to their strategy. Principal component analysis of the matrix of 42 species x 9 attributes shows that the main trend of variation is related to plant size. Larger species have larger seeds, lower relative growth rates and lower reproductive output. The second and third trends of variation are related to plant shape. Ordination of species shows differences in shape between taxa and growth forms (grasses, legumes, forbs). The relative abundance of species with different attributes vary with the level of stress (water and nutrient availability) and disturbance (grazing and ploughing). Size is related to stress, with larger plants dominating in productive habitats and smaller ones in the most unproductive. Disturbance is related to shape and phenology, since grazing favours species with low canopies and ploughing favours species with shorter life cycles, that are usually small in size. Relations between plant attributes and habitat characteristics are examined within the more general framework of plant strategy theory.

Plant drought survival under climate change and strategies to improve perennial grasses. A review

“…These grasses evolved in association with annual species in Mediterranean grasslands (Naveh 1960). Annual species dominate these plant communities and complete their growth cycles before the onset of summer drought, thus minimising competition for limiting resources with the summer-dormant grasses (Fernández-Alés et al 1993). Preliminary research suggests that summerdormant grasses originating from the Mediterranean Basin and introduced to Mediterranean environments of California have very limited potential for invasiveness when compared with introduced Mediterranean annuals and native summerdormant grasses (Vaughn et al 2011).…”

“…In Northern Africa, animal production is widespread and mostly extensive, often with a strong negative impact because of overgrazing on rangelands. However, greater production of animal products is required to satisfy the need of growing populations (Delgado et al 1999;FAO 2009). In Morocco for example, public actions ('Plan Vert') have been implemented to foster livestock farming.…”

The Effect of Timing of Grassland Management on Plant Reproduction

“…No obvious growth-form-related defence mechanisms, such as thorns, occurred among the analyzed species. Low-growing plants can be expected to be able to escape cattle herbivory to some extent [22], but plant height was not correlated with fruit set in this study.…”

“…This disturbance is necessary for grassland ecosystems since it maintains openness and counteracts succession towards tall vegetation dominated by few competitive species. Plants in grassland habitats are adapted to the disturbance, for example, by mechanisms related to palatability and mechanical defence [19,20], growth form [21], and phenology of reproduction [22][23][24]. Phenology can be assumed to be a particularly important trait in mown and other late managed habitats since it determines whether a plant can produce seeds before the vegetation is disturbed [25].…”

Plant functional groups based on vegetative and reproductive traits in a subtropical forest community

“…Some of them, for example, Vile et al (2006) who examined 34 herbaceous species, have proposed that plant ecological strategies can be quantified and modeled by principal components analysis, and some of them have tied PFTs with environmental factors such as linking tree growth of PFTs to habitats (Kariuki et al 2006), or to stress, grazing, and ploughing (Fernández-Alés et al 1993), and to strategies of soil water uptake (Golluscio and Sala 1993). However, many of the previous surveys for PFTs mainly focused on herbaceous plants community on grassland but not on woody species in a forest, such that growth form or/and life form are still popular terms used up until now in this field for depicting woody species-groups within a forest community, in which terms the climate adaptability of species is mainly taken into account.…”