The Impact of Climate Change and Human Habitation on Long‐Term Ecological Stability
Timothy L. Staples, Wolfgang Kiessling, John M. PandolfiABSTRACT
Aim
Direct human impacts and climate change jeopardise the stability of ecological systems. Recent trends are built atop a long history of vegetation change from the Pleistocene deglaciation and Holocene human population expansion. We aimed to model a long‐term measure of ecological stability over the last 20,000 years, a period that includes both the most recent global warming and the spread of human civilisation.
Location
Europe and North America.
Time Period
0–20,000 years before present.
Major Taxa Studied
Land plants.
Methods
We quantified persistence, a non‐equilibrium estimate of ecological stability, across millennia of plant assemblage change proxied within palynological sediment cores. We modeled trends in persistence over time and based on historical reconstructions of human population density, contrasting trends between Europe and North America, continents with broadly similar biomes but divergent land‐use histories.
Results
The late Pleistocene deglaciation produced a prolonged ( c. 10,000 years) period of vegetation destabilisation. Despite continental differences in persistence during the deglaciation, we observed a synchronised increase across Europe and North America at the start of the Holocene. Human land use was linked to greater stability of North American vegetation in the early‐mid Holocene, with some evidence of destabilisation after European colonisation. European assemblages began destabilising 3000 years ago, a trend that has become more severe over time and in areas of higher human population density.
Main Conclusions
We provide a quantitative measurement of assemblage persistence, with trends over time that map onto climatic and human pressures. While palynological trends include responses to climate change, human actions and other assembly filters, with accompanying time‐lagged responses and extinction debts, we found a detectable signal that human land use can suppress and amplify long‐term ecological stability. In recent millennia, human actions have systematically destabilised temperate vegetation, reducing the biosphere's resilience prior to modern anthropogenic climate change.