**3. Results**

#### *3.1. Species Geographical Distribution*

All locations where the species was observed lie along south-facing, very rocky slopes, at the cliff foot of the mountains Symvolo and Rhodope, at low altitudes (100–150 m asl), approximately 3–15 km from the Aegean Sea, just over the plain (agricultural) area lying between the sea and the mountains. The area of the species appearance is restricted to this altitudinal zone, suggesting that these specific ecological conditions favor its thriving. However, the core population of the species was found more westward with respect to the location indicated in the previous records, at 40◦5816.59 N, 24◦2754.93 E, near the village Chalkero, close to the city of Kavala, approximately 150 km from Thessaloniki (Figure 1), in areas exposed to several anthropogenic actions, such as grazing production, livestock raising, agricultural crops cultivation, presence of vehicles, and generally, in degraded habitats.

**Figure 1.** Map showing the location of the species *Verbascum dingleri* occurrence. Geographical coordinates: 40◦5816.59 N, 24◦2754.93 E.

The climate of this area belongs to the type Csa according to the Koeppen classification system. On the basis of the available data of the nearest meteorological station of Kavala city, the mean annual temperature is 14.6 ◦C, and the mean annual rainfall is 602 mm. The mean monthly temperature during the coldest month (January) is 4.2 ◦C, and that during the warmest month (August) is 26.0 ◦C, while the prevailing wind is from the southeast (SE) [26].

From a geological point of view, the study area is part of the Rhodope massif that consists of metamorphic and plutonic-eruptive rocks. The specific rock types where the species appears are marbles and limestone. The soils are very shallow (depth range 5–19 cm), with an extremely high rock presence (80–85% of the total area) (Figure 2a, Table 1). The soil is alkaline, and the pH value was found to be almost constant (7.8) in all four sampling points, with very slight differences. However, even though the soil is very shallow, it was found to be relatively rich in organic matter (7.18%), with adequate total nitrogen content (0.42%), as well as phosphorous and potassium contents (8.55 ppm

and 336.5 ppm, respectively). Other similar habitats near the species area were investigated during the species flowering period, but we did not locate any additional populations.

**Figure 2.** Photo of the species *V. dingleri:* (**a**) in situ photo near Chalkero village, showing the dominant site characteristics; (**b**) fruits of *V. dingleri*; (**c**) seeds of *V. dingleri* (photos from a stereomicroscope).


**Table 1.** Soil characteristics of the habitat of *V. dingleri*.

The site topography provides a habitat that su ffers from hot and dry weather conditions during the dry summer season. As summer approaches, the sunrays fall almost vertically, causing the soil to dry and exposing the vegetation to high sunlight. This, in turn, results in high summer evaporation rates, causing the drying of *V. dingleri* and other annual plants and eventually their disappearance during the late summer season.

The spatial data analysis showed that the species niche is determined by the afore-mentioned specific site characteristics that favor the species survival and thriving. The species distribution is probably constrained by hard dispersal obstacles or physiological thresholds along environmental gradients rather than by interactions with other species. Thus, the species appears only in dry, rocky, south-faced slopes, with medium inclination, on shallow soils and limestone, under the climate type Csa, and at a short distance from the sea, in the location at 40◦5816.59 N, 24◦2754.93 E.
