An easy entry for me today, I’m simply going to copy and paste someone else work, not plagiarism but with permission from Ceri Sansom. Ceri works for the Environmental Management Division here on St Helena, her husband Ben heads up the division and the team who are helping to restore the fragile habitats of which I spoke about last time. Her very well written account of the challenges they face compliments my last blog entry perfectly. Here I am enjoying the fruits of the work of people like those who work at EMD and here Ceri is explaining the difficulties in restoring somewhere like the Diana’s Peak national park. Please read on, and take a look at Ceri’s Page, its well worth a visit.
And thank you Ceri for allowing me to use your blog.
St Helena’s terrestrial conservation is a story that cuts both ways. It is a story with successes. It is also a story of monumental failure. It depends, to some extent, where you start your timeline.
When the Portuguese stumbled across the island in 1502 it was a unique biosphere; an extraordinary natural treasure. Not that the sailors would have seen it in that light. To them it was land, food, water and a means to extend their domain. So, how to improve it? Add meat (goats) and maybe a few citrus trees and all of a sudden it has become a stepping stone into the ocean and beyond.
Within a few short decades the introduced animal life ate its way through the verdant forests. Humanity worked through a good chunk of the rest for buildings, boat mending and fuel. Who knows how many species and fragile microcosms were lost. In Napoleon’s time there was still a Great Wood at Longwood, but goats and rabbits and man stripped the land, until there were just a few cliffs or high areas that escaped the devastation. With the vegetation went the accumulated soils and the treasures within. Reports of vast volumes of soils being washed from the rocks that lie comfortably at a 35degree angle corroborate the idea that this island is now only 20% of its size only a few, short million years ago. The soils and rocks continue to slide away particularly in scruffy August when the sea becomes cloudy with sediment and it is rockfall season.
Twenty years ago, in 1980 Dr Quentin Cronk, from Cambridge University, spent a few short weeks on the island. He met with George Benjamin, a Saint searching the landscape for lost species. It was a partnership that marked the start of the terrestrial conservation on St Helena that we know it today. Having a passion for rediscovery George had already found the lost St Helena olive (now extinct). During Quentin’s short time here they walked many of the remotest areas of the island scouring cliffs and inaccessible tracts for endemic plants. With George’s extraordinary eyesight he spotted a specimen of St Helena Ebony clinging a tens of metres down an inaccessible cliff below the Asses Ears. George’s brother, Charlie, a fisherman and therefore climber (you have to be good on these cliff tracks with a sack of fish on your back), was sent down on the end of a rope to retrieve cuttings which he bought back up between his teeth. These were duly taken back to Royal Botanic Gardens Kew for formal identification and fortuitously the cuttings rooted on the RMS so not only was there a herbarium sample but live specimens too.
This was the start of a building interest in clawing back the remnants of St Helena’s endemic plants. It has been a long haul with successes and failures.
In the intervening years many others, including Stedson Stroud, have joined the hunt and and found a Bastard Gumwood, a few St Helena boxwoods and the finding of a ‘lost’ group of St Helena tea plants. In the Scotland nursery Vanessa Thomas has bought her breadth of experience from old time Saints and Kew horticultural techniques to bear. Many other ecologists have bought their expertise to the island to catalogue and take the early steps in understanding how the habitats might work – not just for plants but invertebrate life too. EMD, St Helena National Trust and the St Helena Conservation Group all contribute to the effort. Serious efforts have been made to squirrel away seed collections for storage and to create living collections on island. But all is not rosy. There are significant hurdles that are only on the periphery of research, let alone action.
The problem with finding ‘the last one’ of anything is that the genetic variation is tiny and unrepresentative, and this makes the offspring inbred and weak. For example, take the Irish potato famine. That was (at least in part) down to the lack of genetic diversity in the potato so the entire harvest failed as a result of a particular fungal attack, resulting in the starvation of a nation. The same is true of any single plant. Often they are hard to breed from and the offspring are uncommonly fragile and vulnerable. This is a problem facing many of the endemics here. The population sizes have dwindled and although now bulked up and apparently healthy, the population will be less resilient than a more diverse collection. It is an issue that will continue to be felt, particularly with the advent of climate change and reduced habitat imposing more challenging conditions on the plants.
Another, seemingly more subtle, problem is that of lack of fungi in the soil. Many plants rely on fungal association (so fungi and plant roots grow in alliance to the benefit of both) to allow them to extract the nutrition from soils. For some species it is absolutely essential, for others it is the difference between spindly and robust growth. It is not a process that is widely understood, least of all on St Helena, although some root samples retrieved by Prof Cronk in years gone by would suggest that there may well be particular fungi that support particular plants. This is a problem. Firstly, because it means it is not possible to just pop plants in the soil and assume that that they will grow, as in most areas of re-colonisation the soil containing the necessary fungal spores has gone. Secondly, it means it is probably not possible to add some generalist fungi (if it were agreed with biosecurity) to the mix and hope more vigorous trees are produced. An example perhaps is that of the gumwood. These should be wonderfully open canopy gnarled daisy trees, and yet a noticeable proportion of the trees that have been carefully planted seem to get to a certain height and then stop. And then die. Because there are so many factors at play it is hard to identify what horticultural practices may entice these beautiful umbrella shaped trees back to their full habit, but depleted soils do not help.
When you present a case you should use no more than three points to make a case, or so I’ve been taught. So now I’m faced with a dilemma. I want to talk about the daily challenge of not allowing species to go extinct (St Helena Olive extinct, Bastard Gumwood last adult dead seeds in propagation, False Gumwood last specimen in the wild dead and a stiff fight for the large bellflower), fragmentation of habitats, increasing pressure from more types of invasives with consequent increase in labour intensive methods to preserve habitats, shrinking good quality habitats and the impact of short term project funding compromises conservation. They are all significant challenges and they all affect the resilience of habitats to climate change and water supply. But I have intruded on your time enough.
Prof Cronk has returned to St Helena, which I hope marks only the end of the beginning. He is delighted with the recolonization programmes, the opportunity to learn from them and although the Benjamin brothers are no longer here to share his enthusiasm, it builds on their extraordinary commitment to conservation. Although St Helena has a habitat that is a shadow of its former self, it still is the home of 30% of the UK and British Overseas Territories endemic biodiversity – something that has to be worth protecting and cherishing. But it will take work, expertise, commitment and funding to preserve what we have left.