Intraspecific phenotypic variability of plant functional traits in contrasting mountain grasslands habitats

Abstract

29 Empirical studies that link plants intraspecific variation to environmental conditions are 30 almost lacking, despite their relevance in understanding mechanisms of plant adaptation, in 31 predicting the outcome of environmental change and in conservation. Here, we investigate 32 intraspecific trait variation of four grassland species along with abiotic environmental 33 variation at high spatial resolution (n=30 samples per species trait and environmental factor 34 per site) in two contrasting grassland habitats in Central Apennines (Italy). We test for 35 phenotypic adaptation between habitats, intraspecific trait-environment relationships within 36 habitats, and the extent of trait and environmental variation. We considered whole plant, 37 clonal, leaf, and seed traits. Differences between habitats were tested using ANOVA and 38 ANCOVA. Trait-environment relationships were assessed using multiple regression models 39 and hierarchical variance partitioning. The extent of variation was calculated using the 40 coefficient of variation. Significant intraspecific differences in trait attributes between the 41 contrasting habitats indicate phenotypic adaptation to in situ environmental conditions. 42Within habitats, light, soil temperature, and the availability of nitrate, ammonium, magnesium 43 and potassium were the most important factors driving intraspecific trait-environment 44 relationships. Leaf traits and height growth show lower variability than environment being 45 probably more regulated by plants than clonal traits which show much higher variability. We 46show the adaptive significance of key plant traits leading to intraspecific adaptation of 47 strategies providing insights for conservation of extant grassland communities. S but is also widespread in habitat N where it is scattered in small patches on rocky outcrops 180 and on shallow soil. L. corniculatus, one of the most important legume species in dry and 181 nutrient poor grasslands, is less abundant on both slopes but shows a similar distribution 182 pattern. The species can grow clonally by hypogeogenous rhizomes (own observations from 183 the present study), it develops tap roots and has a high capacity to withstand soil erosion and 184 is a highly efficient accumulator of nitrogen, for which it is used also in agricultural 185 management (Carter et al.1997 processes (see Table 2): (i) leaf traits (specific leaf area [SLA]; leaf dry matter content 199[LDMC]), (ii) whole plant traits (height; horizontal stem length), (iii) clonal traits (no. of 200 bifurcations/nodes per cm; distance between bifurcations/nodes) (see Table 2). As an 201 exception, seed traits (iiii) (i.e. seed mass and seed germination), were measured from a 202 random rate of seeds collected from all individuals in each habitat. The trait sampling 203 followed standard procedures (Cornelissen et al. 2003; Kleyer et al. 2008). In particular, leaf 204 traits were measured on three leaves per individual; after the measurement of the fresh weight 205 and area, the lea...

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