Galapagos has two seasons largely at the mercy of the ocean currents that interact around the islands. They are known as the hot season and the cool, or garúa (mist) season. The mist is caused by the cool ocean currents that dominate at this time of year that cool the overlying air. Warmer tropical air sits above this layer and a temperature inversion is created. Where the two layers meet, moisture in the form of clouds is precipitated out at an altitude of a few hundred metres. Guess what altitude we are at.
I am assisting the Galapagos natural scientist, Mandy – Mark’s wife – as she carries out vegetation mapping for her PhD studies. We are bushwhacking through dense, damp undergrowth close to the Media Luna – a small, but prominent old crater in the Santa Cruz Highlands. She’s the expert plant ecologist and I’m the chap who fills in the record sheets while asking searching questions about the local ecology, climate, island-life, etc. Like Mark, Mandy is from Australia, and they are returning to Australia in a month’s time to start a new life after many years in the islands. Mandy is resourceful; on realizing she has forgotten her surveying pole and measuring tape, she fashions a pole with her machete from a three-metre-long, straightish, dead tree branch, and a seven-metre measuring tape from a piece of string she finds in her bag. We mark this every 25cm with duct tape using a piece of standard A4 paper, which, apparently, is 25cm long!
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| Mandy in her element |
Mandy is researching the vegetation of the highlands in relation to old aerial/ satellite photography to determine the rates of change caused by introduced species. Ultimately this will assist planning for the management of invasive plant species.
About 97% of the islands belong to the Galapagos Islands National Park, which is also a UNESCO World Heritage Site. We are in the national park, but on the edge of a large concession to farmland, which occupies a large area of the damper uplands on the island. The demarcation between the two is marked – a barbed wire perimeter fence separates the wild land from the farmed. From the other side of the fence an audience of cows watches us through the mist – the whole scene reminds me of an autumn day back home. I guess we’re the most excitement they’ve had for a while.
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| Our audience |
Why is this important? There are many reasons: if a species disappears, so does its unique genetic library – something that could be valuable to people in the form of potential medicines, genes for improving commercially important species that we used for all kinds of things (medicine, food, materials, to name three); reducing the number of species may reduce the ability of the environment to recover from a serious disturbance – which is of particular importance to islands subject to the rigours of a harsh climate, fire, and volcanic eruptions – this environmental resilience is important to people because it helps to mitigate against soil erosion, reduced water supply and moderation of the local climate, for example; also, to lose a unique, flagship species that hundreds of thousands of visitors come to the islands simply to look at, could have direct economic consequences.
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| Standing, but dead, Cuban cedar |
In the national park Cuban Cedar is controlled by hacking the trunk with a machete/ axe just above ground level and applying tree-killing herbicide. The dead trees remain standing for years, clothed in straggling mosses and ferns and, silhouetted in the mist, appear like a scene from a horror film. As my imagination starts to overtake me, from somewhere in the green kaleidoscope that has temporarily swallowed her, Mandy yells out the Latin name of another plant for me to scribble down, jolting me back to reality and forcing me to focus on trying to be professional again.
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| What did you say Mandy? |
Every now and then, the mist lifts enough for us to see across the coastal plain to Puerto Ayora on the coast, several kilometres to the south. There are four main ecological zones defined in the Galapagos and strongly affected by altitude and orientation. They are the coastal, dry, transitional and humid zones, recognizable largely by their vegetation (see images), and forming well-defined concentric rings around a volcanic centre.
One day, on an almost expeditionary, 30-plus mile bike-ride, I head inland from the coast and up-hill. The zonation is obvious to anyone who cares to look – and it helps extract your mind from the effort of the up-hill exertion. Initially, in the coastal zone, I notice plants such as the saltbush and mangrove, which appears to relish growing in harsh, black lava rock. After a couple of minutes of cycling over flat terrain, the dry zone is dominated aesthetically by the Opuntia tree cactus – a species of cactus that is found nowhere else on the planet. The vegetation is thorny and practically impenetrable to all but a determined Galapagos bulldozer – the giant tortoise. As the flanks of the volcano are reached and the pedalling starts to get harder with the steepening slope, the equatorial sun beats down turning my head red almost instantly, and I emerge from the dry zone into the transitional zone. This is characterised by the disappearance of tree cacti, a generally greener, lusher appearance and taller trees with epiphytes (plants that grow on other plants) and a profusion of herbaceous vegetation. After 40 minutes or so of up-hill pedalling, lungs bursting and soaked in perspiration, I reach the humid zone where everything appears one or other shade of green and is generally dripping with moisture (or at least it was when I was there). Here we find the Galapagos guava, Galapagos coffee, a variety of mosses, ferns and fungus. The air is, thankfully, cooler, with a refreshing breeze and a fine mist. I stop at a small shack for a sugary drink and rest before the long descent, unfortunately slow and tedious due to the puncture I have acquired a puncture!
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| Up-hill struggle in flip-flops! |
Mandy and I are working in the humid zone, in a Scalesia forest. Scalesia, also known as the giant daisy tree, is found nowhere else on the planet. It is generally a smallish tree with a rounded, umbrella-shaped canopy. There are two species; one is almost extinct, the other – the type I am leaning on – is more widespread. Naturally, these forests typify the vegetation of the damp highlands, but are under threat from invasive species. One of the worst invasive plant species is Mora – an attractive, white-stemmed blackberry with fruits that taste identical to the UK blackberry that is threatening to engulf my garden back home. The Mora is highly invasive and produces thousands of seeds per plant, which are spread by birds. It is rapidly taking over large tracts of forest as it forms dense stands smothering understorey plant species, including the next generation of native trees. Using current techniques it is very difficult, if not impossible, to control. Mandy’s husband, Mark, believes that the only effective way to control it is through the introduction of a bio-control agent – a disease or insect that selectively will only attack this introduced plant. However, introducing such a thing to the Galapagos is mired in politics leading to Mark’s current frustration, meanwhile the problem only intensifies – watch this space!
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| Scalesia forest |
Mandy’s last transect of the day is through a dense stand of the spiny Mora. She is forced to wield her trusty machete, which she does with the skill of a surgeon’s scalpel, although I stand at a safe distance, just in case.
After the final transect, we are finished for the day. Mandy invites me back to her and Mark’s house in Puerto Ayora for a cup of tea. Marks provides it – and it’s the best cup of tea since the Ty-Phoo experience I had in the US Army Corp of Engineers Office back in Florida, made by Michael, the Lieutenant Colonel. Mark takes me on a tour of their interesting house. There is not a right angle in it. There are two spiral stair-cases; one on the inside and one on the outside – like it was inspired by the DNA double helix. All the internal walls are curved. The third floor offers a roof patio where we stopped for some more restoration chit-chat. Mark relaxes in his hammock and I sip the tea. The view over the town to the picturesque port is pleasant and the sea breeze is cooling. For the first time on this journey I feel quite relaxed having spent a day, in a small way, contributing to Darwin's legacy.
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