Even though in my blog I have tended to favour the opposing
argument to the conventional story, which obviously makes a very good analogy
for the issues human society faces today in regards to environmental
degradation and climate change, I still think that the alternative explanations
offer important lessons.
Vulnerability
A key issue talked about by a number of researchers was the
vulnerability of the environment on Easter. The island received a very small
amount of rainfall, relatively strong winds and a very small amount of volcanic
dust to fertilise the soil (
Rolett and Diamond 2004). Furthermore, the soils of
the island allowed rainfall to percolate very quickly due to it’s volcanic
nature, cutting down freshwater supplies significant, reflected by the island’s
one stream (
Flenley and Bahn 2003). The island therefore had poor soil quality
and a small amount of reliable freshwater, making it almost predisposed to
deforestation. Furthermore, the small size and isolation of the island made it relatively
deficient in biota (
Flenley 1993), giving it very low biodiversity, thus making
it especially vulnerable to invasive species (
Willis and Birks 2006).
I think therefore Easter shows the danger of exerting
pressure on already vulnerable environments. Hunt and Lipo (
2009) showed
evidence of adaption developed by the islanders, but the environment still
declined regardless. In terms of biodiversity and conservation management this
is a key lesson, as identifying areas most at risk of environmental degradation
is a major objective (
Willis and Birks 2006), and the treeless island, almost devoid
of native species of both animals and plants should be a stark warning.
Invasive Species
As mentioned the geography of the island made it especially
vulnerable to invasive species and as I mentioned in a number of posts rats
were likely a key driver of deforestation on the island, gnawing palm nuts to
prevent the forests from regenerating (
Hunt & Lipo 2009). Rats as an invasive
species on a small island would have been able to reproduce rapidly with no
natural predators and prey on the animal and plant life on the island almost
unhindered.
An article on
Britannica discusses the impacts invasive
species can have on ecosystems in depth, noting that they can both reduce an
ecosystem’s biodiversity and cause severe economic harm to the people dependent
on the ecosystem’s biological resources, as rats would have on Easter, through
their use of both palm nuts and animal eggs as primary food sources (
Hunt &Lipo 2009). It is possible that rats not only aided in depletion of the forests
but through their predation of other animal species made further resources more
scarce for the islanders, pushing the Polynesians into pressuring the forests
and the land to make up for this. The effect invasive species can have on ecosystems can be devastating as I have discussed in earlier posts, and indeed likely had a very harmful impact on Easter, so it is important (as conservationists have noted) to take heed of the effect invaders can have on environments, especially fragile ones like Easter's.
So the alternative Easter Island story does provide some
clear lessons for the issues humanity faces today, with environmental
vulnerability and invasive species being key topics in most serious
conservation and biodiversity management schemes.