Tag Archives: Canary Islands

Book review: Vegetation of the Canary Islands by Marcelino J. del Arco Aguilar and Octavio Rodríguez Delgado (Springer 2018)

Figure 1 - Tenerife 2008 - students on the Aeonium field - lo res


This is the text from a book review that’s published this week in The Niche, which is the British Ecological Society’s members’ bulletin.


The Canary Islands mean many things to different people.  To the millions of holiday makers each year they are places of relaxation, of sun, sand, sea and holiday shenanigans.  To Charles Darwin, writing during the early weeks of the Beagle voyage, they were the “long wished for object of my ambition”.  Having read accounts of Tenerife by earlier explorers such as Alexander von Humboldt, Darwin was excited to have the opportunity to visit “perhaps one of the most interesting places in the world”.  Sadly it was not to be: an outbreak of cholera back in Britain meant that the Beagle’s crew would have to be quarantined for 12 days before they could disembark.  Captain FitzRoy was not prepared to do this and so the Beagle moved on.

I recount this story to my University of Northampton students each April when we visit Tenerife for our annual field course.  Referring to it as “Darwin’s Unrequited Isle”, I point out how fortunate they are to live at a time when a short plane flight can take them from the UK to such a fascinating natural laboratory of in situ evolution and biogeographical processes (Figure 1).  We’ve been going to the island since 2003 and we’re certainly not the only European university to do so, I know of at least five others in the UK alone.

To ecologists and those interested in natural history the Canary Islands are a fascinating mixture of the exotic and the banal.  Endemic succulent spurges (Eurphorbia spp.) grow with non-native prickly pear cacti (Opuntia spp.), traditional cafes serving tapas and local wines butt up against sports bars providing a full English breakfast with a pint of Carlsberg for less than five Euros.  The rapid development of tourism on the islands means that there are enormous pressures on land for building apartment complexes, as well as on water resources, energy generation and wastes management.  The islands are a laboratory for sustainable development as much as they are for evolution.

The literature on Canary Island ecology, biogeography and conservation has grown quickly, much of it fuelled by the education opportunities afforded by the islands.  As the authors of Vegetation of the Canary Islands note, the book is both “a synthesis of numerous publications….[and data and experience].…from many years of teaching and research…at the University of La Laguna”.  This fieldwork-focused, dusty boots approach to understanding the Canary Islands flora is apparent throughout the volume which has clearly been a labour of love for the highly knowledgeable authors.

The book is divided into eight chapters, plus appendices. Chapter 1 entitled Geographic Framework gives a summary of the physical geographical and geological context of the islands in relation to the rest of Macaronesia, and explains something of the human history of indigenous peoples (collectively termed the Guanches) and the later European colonisers.  The population of the islands (estimated to be 2.1 million in 2016) swells by an order of magnitude with close to 15 million tourists visiting that same year.  One of the attractions for north Europeans is dealt with in Chapter 2 Canary Climate   Although categorised as subtropical, the weather can be hugely variable, especially on the more mountainous islands; we have experienced blistering heat, torrential rain and snow storms in April in the higher reaches of Tenerife (which at 3,718 m is the second highest island in the world).  Irregular and geographically sporadic rainfall is a particular feature. This leads neatly into Chapter 3 on Bioclimatology that relates this climatic variability to the plant communities of the islands.  A sense of how complex this is can be gauged from Table 3.4 that lists 57 different bioclimatic combinations and their associated vegetation types, many of which overlap.

Chapter 4 on Biogeography considers how the islands have been colonised over a time scale that goes back more than 65 million years, including islands that no longer exist, having eroded and become submerged, but which in the past acted as stepping stones for colonisation of species from the continent and between archipelagos.  This includes some fascinating speculation regarding the role of much earlier island groups to the south west of the Canary Islands that may have allowed exchange of plants between Africa and the Americas, and that could explain some intriguing disjunctions in current distributions.  There is also a very useful summary of endemic genera.

Chapter 5 Other Floristic Considerations initially looks at the non-vascular flora of algae, fungi, lichens and bryophytes, which is rich (5508 species compared to 2091 vascular plants) though the rate of endemism is not so high.  There is then more comparison of diversity and endemism between plant families and islands, followed by a summary of molecular taxonomic findings.  Given how short it is I think that this chapter could easily have been incorporated into the previous one, though that’s a minor criticism.

The bulk of the book (from pages 83 to 308) is taken up by Chapter 6 Vegetation of the Canary Islands which provides a very detailed arrangement of the flora in the classical Braun-Blanquet form using names adapted from the species that are characteristic of that community (“Nerio-Tamaricetea”, “Morello fayae-Pinetum canariensis”, etc.).  To ecologists not trained in this tradition, and more used to the National Vegetation Classification (NVC) scheme familiar to us in Britain, this terminology can seem a little daunting.  Fortunately the introductory section provides a broader classification of the vegetation into categories such as “Euphorbia scrub and shrublands”, “Laurel forest”, etc.  This is a good stepping off point for anyone interested in understanding the vegetation further, before plunging into the subsequent sections that examine these communities in great detail.  The later coloured maps of the potential natural vegetation of the islands, without anthropogenic interference, are especially useful for teaching.

This leads us into Chapter 7 which deals with Changes in the Natural Landscape Through Human Influence.  As the authors point out, people have influenced the vegetation since the earliest period of human settlement on the islands, about 1000 BCE, as these arrivals brought with them livestock such as goats, sheep and pigs, as well as useful plants.  However this process was hugely accelerated from the 15th century onwards as Europeans rapidly conquered the islands and cleared large areas of forest, as well as introducing many more invasive species.  The chapter ends with a very thought provoking section on climate change and its likely effects.

Chapter 8 considers the Conservation Status of the Canarian Flora and Vegetation, providing a history of how protected areas were set up, including the designation of seven UNESCO Biosphere Reserves and two Natural World Heritage Sites. Lists of protected plant species and their various designations are also provided and there’s a short summary of invasive species.

The four appendices give: (1) an over view of the phytosociological scheme for understanding the communities; (2) a short history of botanical exploration of the islands,  which emphasises just how many botanists and ecologists the archipelago has attracted over the years; (3) notes on the ethnobotany of the islands; (4) and a long list of relevant literature, extending over 18 pages.  A weakness of the book is that the literature is not cited within the text, presumably for reasons of readability.  This does make it much more difficult to track specific sources of information back to its origin, however. The text concludes with two indices, one phytosociological and one taxonomic.

The book is well illustrated with both colour and black and white photographs and figures, though the quality of some of these in the e-book version that I was provided with for this review were not as sharp as they could have been.  I hope that the print version is better quality.

Vegetation of the Canary Islands will appeal to anyone interested in the ecology of this most fascinating of archipelagos, though at £119.99 for the hardback it is expensive.  It should certainly be bought by any library of a university that carries out teaching and research on the islands.  The earlier and later chapters will be of most use for students and their teachers; the central sections on phytosociology really require more specialist knowledge, though there’s a lot of fascinating ecology in there for the patient reader.  One thing that did surprise me about the book is that the role of fire in determining the type of vegetation in an area is hardly considered, except as it relates to the negative consequences of large wild fires.  Yet many of these habitats must have burned naturally before people arrived on the islands, as evidenced by the amazing ability of Pinus canariensis to re-sprout after it has burned (Figure 2).

During our field course in Tenerife the students and staff spend a week exploring the different plant communities of the island, as well as bird and bee behaviour, and half a day of sea mammal observation.  I’ve used it as an opportunity to conduct long term data collection that otherwise would never get funded (see Figure 1), and some of this research has already been published.  Two other books that I’ve found useful and which should be on the bookshelves of anyone wishing to learn more about Darwin’s Unrequited Isle are: Natural History of Tenerife by Philip and Myrtle Ashmole (2016) and Tenerife Nature Walks by Sally Lamdin-Whymark (2013).  Both are available on Amazon.

Figure titles:

Figure 1:  University of Northampton students surveying a population of Aeonium urbicum, Santiago del Teide, Tenerife, 2008.  This monocarpic species is the subject of long-term data collection to assess what triggers flowering.

Figure 2:  Post-fire regeneration of Canary Island Pine (Pinus canariensis) on Tenerife 2008-2017.  Most species of pines are killed by fire; P. canariensis is one of the few that can re-sprout following a burn.

Figure 2 - Pine forest burn sequence.jpg


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Filed under Biodiversity, Tenerife, University of Northampton

Why conservation is like paella: thoughts and photos from our Tenerife field trip


A couple of days ago I posted a photograph on Facebook with a comment that “after a hot day of collecting data there’s nothing better than a nice big Tenerife paella!”:

Karin and the paella.jpg

My wife Karin and I had ended up in the small town of Candelaria, tired and hungry after sweating our way through the Malpais de Guimar  counting and measuring plants.  Big plates of hot food were just what we needed!

After I posted the image a Spanish colleague commented that the dish was “closer to being an arroz con cosas than a paella”.  The term translates as “rice with things” and is used to convey the fact that the original Valencian dish of paella has been bastardised and changed across the Spanish-speaking world, and no longer reflects its culinary tradition.  Knowing nothing of that culinary tradition I took a look at the Wikipedia entry for paella.  It makes for interesting reading, not least the fact that in the original dish one of the main ingredients was the meat of water voles and that the dish was cooked on an open fire fuelled by wood from orange and pine trees to give a distinctive smoky flavour.  There was also a lot of geographic variation in the dish, so what constitutes an authentic paella is debatable.

Although there was no sign of rodent flesh or naked flames in the dish that we ate, it was certainly delicious!  But the comment about arroz con cosas got me thinking about shifting baselines in cooking and conservation.

The idea of a shifting baseline is that expectations of what is “correct” or “normal” or “natural” change over time depending upon what each generation has experienced.  It’s been mainly applied in conservation; for example, the Lake District of England is seen by many as a “natural” landscape of rolling hills and low mountains, but originally it would have been covered in deciduous forest.  Likewise large parts of Tenerife contain a high proportion of alien plants (such as agave and prickly pear) but local people and visitors see this as natural.  The baseline of “naturalness” has shifted for people.  Returning these landscapes to their original condition would mean a drastic shift in the composition of the vegetation.  And what point do we return that condition to?  One hundred years ago?  One thousand?  Ten thousand?  It’s an issue that is widely debated in the conservation literature, especially in relation to rewilding.

Likewise, over time paella has evolved and been adapted by different chefs, and what is currently cooked in restaurants only partially reflects how the dish was originally cooked.  Other than for epicurean purists, our culinary expectations have changed.  There’s been a shift in the paella baseline.

Anyway, enough metaphorising, here are some photographs from our trip.  To set the context, University of Northampton students and staff, including Pablo Gorostiague who is visiting from Argentina, and colleagues from the University of Sussex (Maria Clara Castellanos and Chris Mackin), were out with us last week.  Then we bade them farewell on Sunday before moving on to do some field work.

Field work on the lava fields at Santiago del Teide:

Santiago del Teide 2018-04-28 11.21.30.jpg

Santiago del Teide 2018-04-28 11.23.30.jpg

Santiago del Teide 2018-04-28 12.20.48.jpg

The landscape of Malpais de Guimar, which actually probably hasn’t changed much in the last 10,000 years:



How many people can you fit around Pino Gordo, the largest Pinus canariensis on the island:

Pino Gordo 2018-04-24 12.10.41.jpg

Pino Gordo 2018-04-24 12.10.50.jpg

Pino Gordo 2018-04-24 12.11.09.jpg

The endemic Tenerife Blue Chaffinch:


The cold, damp laurel forest:


Team Nicotiana!  Helping Chris with locating Tree Tobacco populations for his PhD work:

Team Nicotiana - 2018-04-27 11.52.15.jpg

Team Nicotiana 2018-04-26 10.13.13.jpg

Pablito takes a break:






Filed under Biodiversity, Biodiversity and culture, Rewilding, Tenerife, University of Northampton

Local and regional specialization in plant–pollinator networks: a new study just published

Euphorbia canariensis pollinators 2016-04-29 17 58 00

A fundamental feature of the natural world is that no species exists in isolation: all organisms interact with other organisms during their lives. These interactions take many forms and the outcome varies with the type of interactions. For example predator-prey interactions are clearly negative for the prey species, but positive for the predator. Other interactions result in positive outcomes for both species, including relationships between pollinators such as bees, birds and flies, and the flowers that they pollinate. An important feature of such interactions is how specialized or generalized it is; that is, how many different pollinators are actually involved in pollinating a particular type of flower, or how many types of flower does a specific pollinator visits.

In a newly published study, I have collaborated with colleagues from Denmark and Brazil to assess how local specialization (within a community) relates to regional specialization (across communities) using two separate data sets from the Brazilian rupestrian grasslands and Canary Island/North African succulent scrub vegetation.

Here’s the citation with a link to the paper (drop me a line if you can’t access it and need a PDF):

Carstensen, D.W., Trøjelsgaard, K., Ollerton, J. and Morellato, L.P.C. (2017) Local and regional specialization in plant–pollinator networks. Oikos (in press) doi:10.1111/oik.04436

The abstract is as follows:

“Specialization of species is often studied in ecology but its quantification and meaning is disputed. More recently, ecological network analysis has been widely used as a tool to quantify specialization, but here its true meaning is also debated. However, irrespective of the tool used, the geographic scale at which specialization is measured remains central. Consequently, we use data sets of plant–pollinator networks from Brazil and the Canary Islands to explore specialization at local and regional scales. We ask how local specialization of a species is related to its regional specialization, and whether or not species tend to interact with a non-random set of partners in local communities. Local and regional specialization were strongly correlated around the 1:1 line, indicating that species conserve their specialization levels across spatial scales. Furthermore, most plants and pollinators also showed link conservatism repeatedly across local communities, and thus seem to be constrained in their fundamental niche. However, some species are more constrained than others, indicating true specialists. We argue that several geographically separated populations should be evaluated in order to provide a robust evaluation of species specialization.”

This is what those two different habitats look like:

If you would like more information on plant-pollinator networks, including details of an edible game for Christmas (!), follow this link to the standingoutinmyfield blog.


Filed under Bees, Biodiversity, Biogeography, Brazil, Macroecology, Mutualism, Pollination, Tenerife

Spiral Sunday #31 – hola Tenerife!

Tenerife graffiti spiral P1010967.png

In a few hours I’m heading of to Tenerife with students and colleagues for our annual undergraduate field course, following which I’m staying on to be joined by Karin for a further 10 days of field work.  I’ll try to post as and when I can, though it’ll be a packed few weeks.

In the meantime this week’s Spiral Sunday is a piece of Canarian independence graffiti that I photographed a few years ago on the road above Guimar.  As I’ve mentioned before, the spiral is an ancient and important symbol in the Canary Islands.  Adios!

Tenerife graffiti spiral - full P1010968.png

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Spiral Sunday #10 – a shrine in Tenerife


To celebrate number ten in my series I thought I would fulfil a promise that I made in Spiral Sunday #1 to tell the story behind the main image of a blue spiral that adorns this blog.

In 2008 I was leading a group of students on a walk in the Anaga region of Tenerife during our annual undergraduate field course to the island.  We were hiking through laurel forest along the trails from the restaurant at Cruz del Carmen,  looking at the forest and cliff vegetation community structure.  During our lunch break I set off alone down a side trail and came across a shallow recess, a sort of low natural grotto, in the vertical bank that defined one side of the track.

The walls of the grotto were green with lichen which made a vivid backdrop to what appeared to be a small shrine consisting of branches, including one set upright that looked like a human figure with arms raised, or could it represent a crucifix?  Around this were scattered coloured pencils (to the right on the main image) and pieces of paper with writing on them, possibly prayers (on the left).

Most striking of all was a drawing of a blue spiral, its colours smudged and faded with the humidity, but still a conspicuous contrast to the lichen.  I took a few photographs, being careful not to disturb the display, then headed back to catch up with the students.

There is a strong local sense of traditional, pre-Spanish identity in this part of Tenerife and it is well known for its local stories such as the “Witches of Anaga“, and it’s possible that this shrine relates to local ritualistic practices.  The spiral is a traditional design used by the original Guanche inhabitants of the Canary Islands and still regularly found on logos, pottery, etc.  Alternatively what I discovered could have been just kids playing in the forest, though that seems unlikely as it’s off the beaten track and not close to any villages.

I’ve occasionally found other ritualistic items on the island (e.g. a child’s doll wrapped in cloth, with folded paper in the bindings) but the Anaga spiral shrine was a particualrly striking discovery.  When we returned with the field course the following year the spiral had disintegrated but the rest of the shrine had been tidied up and more neatly arranged (see lower photograph).  I wonder if it’s still there?





Filed under Biodiversity and culture, Tenerife