In São Miguel, our task was made easier thanks to the previous work of Pr. Dr. Rui Elias and Fernando Pereira, who chose and delimited the sampling plots during June and July in order to catalog the existing vascular flora. Despite some rain and heavy fog on the second to last day, the weather was mostly good, allowing the six altitudes of the gradient to be sampled relatively fast, within 3 days. The transect ranged from 50 to 1000 m and was set up along the southeastern side of the island (Fig. 1).
The aim of this report is to briefly describe the sampling sites and illustrate the gradient with some photographs.
50 m – Pelado viewpoint (Fig. 2)
Plot 1 coordinates: N37°51'00,1''; W25°09'00,8''
Plot 2 coordinates: N37°51'00,1''; W25°09'01,8''
|Fig. 2: Vegetation at the Pelado viewpoint (D. Henriques)|
The vegetation surrounding this viewpoint in the Nordeste municipality is included in the Pelado Endemic Park, a protected area that still maintains some vascular endemics, which nowadays are rare or even completely absent at this elevation in the rest of the island. The proximity to the ocean makes this a somewhat arid region (hence the name “Pelado”, which loosely translates to “hairless” or “bald”) with low vegetation (less than 5 meters high), predominantly composed by Erica azorica and Morella faya. Bryophytes are more abundant in the soil.
200 m – Ribeira Quente (Fig. 3)
Plot 1 coordinates: N37°44'26,2''; W25°18'12,6''
Plot 2 coordinates: N37°44'26,7''; W25°18'10,8''
|Fig. 3: The dominant presence of Hedychium gardnerianum is obvious at 200 m ( D. Henriques)|
Like most places at this altitudinal level, the Ribeira Quente area is greatly disturbed due to human activity. The forest patch, situated in a very steep slope (about 50°) is dominated by the non-native species Pittosporum undulatum at the canopy level and Hedychium gardnerianum in the undergrowth, with the sporadic presence of native trees like Laurus azorica, Picconia azorica and Morella faya. Bryophytes were mostly present on rocks and as epiphytes.
400 m – Lomba do Botão (Fig. 4)
Plot 1 coordinates: N37°46'26,3''; W25°16'30,4''
Plot 2 coordinates: N37°46'25,9''; W25°16'30,6''
|Fig. 4: The thalloïd liverwort Conocephalum conicum, surrounded by Fissidens sp. (D. Henriques)|
At this altitude we found a somewhat disturbed forest system with the canopy reaching up to 10 meters high. The vegetation is dominated by Laurus azorica, with the less prominent presence of Erica azorica, Picconia azorica, Ilex perado subsp. azorica and Vaccinium cylindraceum. The undergrowth consists mainly of Hedychium gardnerianum, as on the previous altitude, and bryophytes are mostly epiphytes.
600 m – Tronqueira
Plot 1 coordinates: N37°47'56,5''; W25°11'00,7''
Plot 2 coordinates: N37°47'56,4''; W25°11'00,0''
Plot 2 coordinates: N37°47'56,4''; W25°11'00,0''
The Tronqueira region is well known for harboring the small Azores Bullfinch (Pyrrhula murina), an endemic and endangered bird species restricted to a small area of native Laurisilva forest in São Miguel, ranging from 600 m to 1000 m (Pico da Vara). Since the Bullfinch conservation project includes the maintenance and restoration of its original laurel forest habitat, the native vegetation is well preserved and species like Ilex perado subsp. azorica, Erica azorica, Laurus azorica and Juniperus brevifolia dominate the landscape. Nevertheless there is a high amount of Clethra arborea, which behaves as an invasive exotic in this part of São Miguel. Bryophyte cover is predominant on the trees (75%) but also very significant on the soil (50%).
800 m – Salto do Cavalo (Fig. 5)
Plot 1 coordinates: N37°47'16,3''; W25°16'37,7''
Plot 2 coordinates: N37°47'15,7''; W25°16'37,6''
|Fig.5: The moss Myurium hochstetteri found mostly as epiphytes at this locality (D. Henriques)|
Salto do Cavalo is one of the highest points of the Island, from where both the southern and northern coastlines are visible. Its name (which loosely translates to “horse’s jump”) is associated with a legend in which a Portuguese king was saved from riding his horse down the cliff to a certain death by the archangel Michael, in honor of whom the island is named. This area is still part of the Azores Bullfinch distribution range, and its vegetation resembles the one found at the previous altitude. The forest system is dominated by Laurus azorica, with the presence of Ilex perado subsp. azorica, Erica azorica and Clethra arborea.
1000 m – Pico da Vara (Fig. 6)
Plot 1 coordinates: N37°48'35,1''; W25°12'50,5''
Plot 2 coordinates: N37°48'35,0''; W25°12'51,6''
|Fig. 6: The team working on the slopes of Pico da Vara (F. Pereira)|
Pico da Vara is the highest mountain on São Miguel Island, reaching up to 1103 meters at its peak. The vegetation is dominated by scrubland; bryophyte cover is predominant on the soil and shrubs. Vascular species are less than 2.5 m high and Vaccinium cylindraceum and Juniperus brevifolia dominate the plant composition. Other endemics, such as Ilex perado subsp. azorica, Laurus azorica, Prunus azorica, Erica azorica or Viburnum treleasei can also be found in the slopes and contribute to this area’s high endemism level.
At this point, samples of the São Miguel gradient have been curated and processed and will be analyzed at the University of the Azores.
Text and Photographs:
Débora Henriques, Márcia Coelho, Fernando Pereira and Rosalina Gabriel