Flowers on the volcano

Following yesterday's journey we have now arrived close to the summit of El Teide. The landscape is a vast expanse of bleak volcanic rock, including obsidian, phonolite and trachyte, which form when lava solidifies according to different physico-chemical criteria.

El Teide volcano

Teide's most recent eruption dates back to 1909, and some tremors have been recorded in 2004, indicating a dormant volcano may become active in a few years' time.

El Teide's 1909 eruption, live (photo stolen from here)

In any case, the plants seem quite happy about their choice of habitat. A large number of endemic species characterize Tenerife and many of these species are abundant high above the pine forest. The southern side of the Teide, in the Las Cañadas caldera, is a habitat known as subalpine scrub, dominated by shrubs of the legume Spartocystus supranubius L., together with bushes of the beautiful Pterocephalus lasiospermum Link.

dark green shrubs of Spartocystus supranubius L., with Pterocephalus lasiospermus Link in the foreground

Spartocystus supranubius L. with seed-pods

Pterocephalus lasiospermus Link

flowers of Pterocephalus lasiospermus Link

Amongst these one can also find the very interesting Cheirolophus teydis (C.Sm.) G.López, an endemic plant of Teide that is a very close relation of Malta's national (and also endemic) plant, Cheirolophus crassifolius (Bertoloni). Unfortunately all plants were only on the verge of flowering during this visit. Flowers of C. teydis are pale yellowish.

Cheirolophus teydis (C.Sm.) G.López

Adenocarpus viscosus (Willd.) Webb & Berthel. and several species of Echium are also very characteristic inhabitants of El Teide, characterizing landscapes with their yellow flowers and tall spikes respectively.

Adenocarpus viscosus (Willd.) Webb & Berthel.

Echium sp.

Echium sp. flowers

lycaenid butterfly resting on Echium sp.

Above the clouds of El Teide

The third largest volcano on earth (according to some sources, but not to others - it depends on how you go about measuring volcanoes) is found off West Africa, on Tenerife.

To see the majestic peak of this volcano, El Teide, one must traverse a height of about two kilometres of pine forest, dominated by the endemic Canarian pine Pinus canariensis C.Sm. This pine has developed an extraordinary way of utilizing the water available in the mist enveloping these forests - its leaves are tall and thin, allowing condensation of water droplets on their large surface area. This water trickles down, dropping into the soil and providing roots with much-needed hydration.

Pinus canariensis C.Sm., 2.5km up east El Teide

In some places, violent storms some years back have ripped the trees down, the trunks of which together with the flowing clouds produce an eerie atmosphere reminiscent of any horror film worth its salt:

wind-battered pine forest, c. 2km up east El Teide

After the ascent of about another kilometre one can see the forest spread below and a wide swathe of cloud enveloping it:

About 3km up El Teide, the volcano in the background

Coming up next: some local flora.

My first encounter with a Canarian dinosaur

As soon as one starts travelling around Tenerife one starts becoming aware of a particular species of reptile populating much of its landscapes. The first things that struck me about this animal are its fairly large size (about 30cm in males) and its bold colouration, which are features by all means not unheard of in lizards (see here for an extinct Maltese giant lizard); however, being more accustomed to the smaller and much more agile Maltese Podarcis, I was surprised.

The lizards are also fearless and will venture very close to their human observers, especially if food is involved. They are endemic to Tenerife and belong to the species Gallotia galloti Oudart, 1839, which has differentiated into four subspecies around the same island and its neighbours. The ones in the following pictures are from the northern population of Gallotia galloti eisentrauti Bischoff, 1982 in Puerto de la Cruz, Tenerife.

It can be seen here that males are characterized by the larger size and a neon-blue throat, together with several other markings not found in females, which on the other hand are smaller and covered in brown patterns.

male specimen of Gallotia galloti eisentrauti Bischoff, 1982 basking in the sun

male Gallotia galloti eisentrauti Bischoff, 1982

female Gallotia galloti eisentrauti Bischoff, 1982 on the alert

The other subspecies are Gallotia galloti galloti (Oudart, 1839) from southern Tenerife, Gallotia galloti insulanagae Martin, 1985, from the isolated and inaccessible island northeast of Tenerife (Roque de Fuera de Anaga), and Gallotia galloti palmae (Boettger & Müller, 1914) from the island of La Palma.

The lizards are also an icon of the Guanche (aboriginal/ pre-Hispanic) culture on Tenerife, with several depictions and rock carvings still existing and on show in museums. They also ensure a steady income from tourists, their (highly non-realistic) outlines being featured on everything from ashtrays to t-shirts (though I must admit I had to buy one of the latter).

Los Gigantes cliffs in Tenerife

The highest cliffs in the volcanic island of Tenerife, in the Atlantic Ocean, are found on its western side. These majestic geological features are known as 'Los Gigantes' (the Giants), a term which perfectly befits their massive presence.

Acantilados de Los Gigantes, Tenerife

The cliffs are (like much of the island) composed of 'alkali' basalt, a volcanic rock which contains high proportions minerals like feldspar, olivine and iron oxides. These mineral accretions are sometimes large enough to be seen with the naked eye:

feldspar (white crystals) and iron oxides (brown aggregate) in basalt

feldspar (white crystals) and iron oxides (brown aggregate) in basalt

olivine (greenish crystals) in basalt

The basalt is found in layers which are texturally highly varied, each layer indicating a different episode or process in the island's violent volcanic history. For example, the breccia-like ignimbrite forms when a stream of lava partly melts the substrate upon which it is flowing and drags the pieces of hot rock along, subsequently welding the fragments together into a pudding-like composition, in this case containing fragments of widely disparate size:

ignimbrite

Another rock which stands out visually is red ochre, which forms when hot lava passes over well-developed soils. It can be seen as a thin reddish line in the following photograph:

red ochre stratum

Over millions of years, boulders of basalt tumble down the cliffs and are rounded by wave and wind action.

boulders on the shore

As a rough habitat largely characterized by strong currents and abrasive basalt gravel, the interface between the sea and land is largely devoid of macrofauna, though some usual suspects make an appearance. Most notable of these are two Macaronesian endemics - the limpet Patella piperata Gould, 1846 and the periwinkle Littorina striata King & Broderip, 1832. Closer to mean sea level, Patella tenuis crenata d'Orbigny, 1840 makes an appearance. The third species of limpet that may be encountered on Tenerife is Patella ulyssiponensis Gmelin, 1791, though none of these were seen during this trip. 

Littorina striata King & Broderip, 1832

Littorina striata King & Broderip, 1832

Patella piperata Gould, 1846

Patella piperata Gould, 1846

Specimens of Osilinus sauciatus (Koch, 1845) were found in small clusters, mostly using deep cracks as shelter.

Osilinus sauciatus (Koch, 1845)

Some swimmers in Hyde Park

Canada geese (Branta canadensis parvipes (Cassin, 1852)) coming closer to the photographer, hoping for scraps of food.

Eurasian coots (Fulica atra L., 1758) preening while a pigeon (Columba livia Gmelin, 1798) struts by.



Male mallard duck (Anas platyrhynchos L., 1758) taking it easy.

New marine biology papers

1. Mifsud, C. & Cachia, C., 2011. New additions and corrections, with annotations, to the check-list of the marine Mollusca of the Maltese Islands. Triton, 23: 10-18.

This paper is an addendum to the four volumes on marine mollusc records from the Maltese Islands by Cachia, Mifsud & Sammut (1991; 1996; 2001; 2004 - see full references below). In this paper, 99 additional records are mentioned together with a number of corrections of previous records.

Of particular interest is a second species of Paludinella for Malta. This minute snail is rare and lives in marshes, and previously only Paludinella littorina (Delle Chiaje, 1828) was known to occur. Samples from Salina Bay have yielded some individuals of Paludinella sicana (Brugnone, 1876).

A comparison of Paludinella sicana (Brugnone, 1876) and Paludinella littorina (Delle Chiaje, 1828), pictures taken from the Natuurhistorisch Museum Rotterdam collection

Also worthy of mention is the first Central Mediterranean record of the pyramidellid Leucotina eva Thiele, 1925.

2. Deidun, A., Galea Bonavia, F. & Schembri, P. J., 2011. Distribution of Tylos spp. in the Maltese Islands and population dynamics of Tylos europaeus. Journal of Coastal Research, SI 57: 369-372.

Tylos is a genus of woodlice, two species of which - Tylos europaeus Arcangeli, 1938 and Tylos sardous Arcangeli, 1938 - occur on two sandy beaches on island of Gozo. This paper examines their habitat and gives an account of yearly fluctuations in the former's population.

References:

Cachia, C., Mifsud, C. & Sammut, P., 1991. The Marine Shelled Mollusca of the Maltese Islands Part 1: Archaeogastropoda. Malta: Grima Printing & Publishing Industries; 112 pp.

Cachia, C., Mifsud, C. & Sammut, P., 1996. The Marine Mollusca of the Maltese Islands, Part 2: Neotaenioglossa. Netherlands: Backhuys Publishers; 228 pp.

Cachia, C., Mifsud, C. & Sammut, P., 2001. The Marine Mollusca of the Maltese Islands Part 3: Sub-class Prosobranchia to sub-class Pulmonata, order Basommatophora. Netherlands: Backhuys Publishers; 266 pp.
Cachia, C., Mifsud, C. & Sammut, P., 2004. The Marine Mollusca of the Maltese Islands Part 4: Caudofoveata, Solenogastres, Bivalvia, Scaphopoda and Cephalopoda. Netherlands: Backhuys Publishers; 270 pp.

Endangered Species Day 2011

On the occasion of Endangered Species Day 2011, I present one of the most characteristic floral endemics of Malta, namely the Maltese Everlasting (Helichrysum melitense). This plant grows on the cliffs of Dwejra (Gozo) and Fungus Rock, and is most probably extinct in the wild from Malta. The remnants of the population are threatened by quarrying (mostly illegal), dumping of construction materials, alien species and habitat deterioration.

Helichrysum melitense (Pignatti), Dwejra - Għawdex, 21.VI.2008

Sealed destiny?

Monachus monachus (Herrmann, 1779), picture from marinebio.org

The Mediterranean monk seal, Monachus monachus (Herrmann, 1779), sometimes appearing also around Malta (Lanfranco, 1969), is one of the species cited as being 'close to extinction' by the EU environment commissioner Janez Potocnik. About 400 individuals are left around the Mediterranean and many factors heavily influence the decline of the population, including viral diseases, though most threats are anthropogenic.

The Mediterranean Monk Seal on a 2004 stamp from Maltapost

References:

Lanfranco, G. G., 1969. Maltese Mammals (Central Mediterranean). Progress Press: Malta.

MarineBio, undated. Monachus monachus, Mediterranean Monk Seal. [www document, url=http://marinebio.org/species.asp?id=343, last accessed 17.V.2011]

The Roman Villa in Żejtun

Today's edition of the Times of Malta reports that remains of a Roman Villa in Żejtun will be cleaned up and conserved. The following are some pictures taken in 2009 at this site. 

It is interesting to note that, in the course of about two millennia, yellow colonies of the lichen Xanthoria parietina have colonized most of the limestone blocks available, and only rarely are they found growing on the earthenware tiles. This is probably a direct effect of the materials' porosity relative to each other.

A collection of lichens

Lichens are a group of fungi that have, during the course of evolution, entered a mutual association with algae or cyanobacteria, resulting in a complex relationship that benefits both organisms and allowing them to colonize habitats which would otherwise be inaccessible to the fungus or to the algae by itself.

These habitats may range from bare rock to tree trunks; considerable variety is amply demonstrated even in a relatively small area such as the Buskett woodland, where all the following photographs were taken.

Caloplaca sp., a distinctive yellow lichen which covers bare rock

Ramalina durieui, found mostly on thin branches of pine (Pinus halepensis) and cypress (Cupressus sempervirens)

Another 'leafy', cypress-loving species

This lichen appears to prefer dead bark of the pine tree

A black lichen using rock as its substrate. The green growth consists of moss, which, unlike lichen, is a true plant.

A white lichen on rock.