The degradation of an ecosystem triggers a cascade of effects, some of which also affect other ecosystems. The resulting can be an accelerated decay of their resilience. The prospect, says a team of UK researchers, is that the collapse of ecosystems happens much earlier than we expect
The study is published in Nature Sustainability
– A domino effect that can radically change the planet and human societies in a few decades. And much sooner than you think. This is the scenario hypothesized by a study on the Ecosystem collapse that analyzes both the triggers of degradation and the interactions and strengthening mechanisms between one collapse and another.
Normally, the study of tipping points, that is, those points of no return that, if exceeded, cause an irreversible change of an ecosystem, analyzes a single ecosystem and takes into account the factors that directly influence it. And typically the time of the possible collapse is set in the second half of the 21st century. It’s a time of death. Few works, like the one just published in Nature Sustainability, try to shed light on the interactions between different tipping points.
“The acceleration of stress levels, the increase in the frequency of extreme events and the strengthening of inter-system connections suggest that conventional modelling approaches, based on incremental variations of a single stress, can provide insufficient estimates of the impact of climate and human activities on ecosystems,” write the authors.
How the Ecosystem collapse accelerates
To go beyond the limits of this approach, the research team used 4 models to simulate radical changes in 4 different ecosystems (caught in the Chilika lagoon, Easter Island communities, forest decay and lake water quality). The Ecosystem collapse, the authors conclude, occurs first with increasing levels of primary stress, but “additional stress and/or the inclusion of noise in all four models” – that is, taking into account the potential interactions between tipping points – “bring the collapses substantially closer to today’s by about 38-81%”.
Another factor to take into account – so far rather undervalued – is the rate of change to which ecosystems are exposed. The more the rate changes, the less responsive ecosystems are. “Our results show that systems do not collapse to a constant level of cumulative stress (i.e., the total stress accumulated over time) regardless of the rate of stress variation, but rather emphasize the importance of rate versus accumulated stress”, the authors conclude.
