In
order to gather some more data on the bryoflora of the remaining Azorean
islands with significant patches of native vegetation, an expedition following
the methodology of the Moveclim project took place in São Miguel island
(Azores) between the 26th and 30th of August 2013. The
team was composed by Rosalina Gabriel, Débora Henriques, Márcia Coelho and
Fernando Pereira, with the help of Paulo A. V. Borges and Diogo Silva. Three additional transects were done in the Azorean archipelago in the framework of the PhD thesis of D. Henriques, these elevational transects complete the Pico transect originally planned in the Moveclim project, allowing a comparison between 4 transects along a gradient of age from São Miguel (4.1 Ma) to the youngest Pico (0.27 Ma).
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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.
 |
| Fig. 1: Map of the six altitudes of São Miguel transect |
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
