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Vegetation structure and composition of road verge and meadow sites colonized by Cabrera vole [Microtus cabrerae Thomas]

100%

Santos S. M. , Mathias M. , Mira A. , Simoes M. P.

nr 3

This paper analyses the floristic composition and vegetation structure in road verge and meadow sites colonized by Cabrera vole (Microtus cabrerae Thomas, 1906), a threatened rodent with fragmented distribution in the Iberian Peninsula. Vegetation was sampled in 26 colonized patches in five geographical areas of Southern Portugal. The cover of the herbaceous layer was sampled in 1 × 1 m plots. Several variables related to plant diversity, Raunkiaer lifeforms, taxonomic groups, disturbance and soil properties were assessed. Floristic composition of the herbaceous communities of road verge and meadow sites was different. Indicator species of road verges corresponded mainly to annual grasses and forbs, ruderal and nitrophilous species, along with a few perennials. In meadows, perennial grasses and moisture indicative species were more common. Results suggest that road verges are lower quality habitats for Cabrera vole maintenance, due to high disturbance, low moisture availability during summer and reduced patch surface. Nevertheless, they might provide benefits such as extra foraging and refuge, especially in disturbed areas. Potential ecological effects of road verge management are discussed in the light of species conservation goals.

Identification of humidity conditions in meadow site using plant species indexes [phytoindication method]

80%

Oswit J.

nr 84

Variation in size-dependent fitness components in a terrestrial orchid, Dactylorhiza majalis (Rchb.) Hunt et Summerh., in relation to environmental factors

70%

Mroz L. , Kosiba P.

nr 2

We investigated the flowering probability and flower production in relation to plant size in a terrestrial orchid, Dactylorhiza majalis at 10 meadow sites in central and southwestern Poland. These sites differed in altitude (low, high) and management (presence or absence of mowing). At all sites, concentrations of nutrients in the soil were also measured. The probability of flowering increased significantly with the size of the plant in all populations, indicating that individuals do not flower until they reach a threshold size. Populations at high altitudes and the unmown sites had significantly lower threshold sizes for reproduction and showed sharp increase in flowering probability with plant size, compared to other populations. The threshold sizes for reproduction tended to decrease at sites rich in N and Mg and poor in P and S. Flower production was also size-dependent in all populations. Considerable between-site differences were found in the slope and the intercept of the regression between plant size and flower production. Flower production at some sites, at high altitudes, increased more steeply with plant size than at other sites. However, no pattern in size-dependent flower production was found relative to the measured environmental variables. Most of the size-dependent components of flowering probability were related to each other but not with the size-dependent flower production.