Ecosystem-Based Effects

Written by Melanie Lenart, University of Arizona

Climate largely defines where ecosystems occur on the landscape, from deserts to wetlands and tropical forests to tundra. So it’s clear that changes in climate will mean changes in ecosystems around the globe. Not all ecosystems will be displaced, but they all will face potential disruptions and the likelihood of increased disturbance from changing fire regimes and invasions of insects and exotic species.

Some of the specific challenges facing forest ecosystems are described in the following sections, including:

• threats to biodiversity as species shift – or attempt to do so – in response to changing climate, and
• impacts on soil nutrients and soil carbon storage,
• changes in the water cycle that can affect streams, lakes, and other aquatic habitat.

While species and ecosystems have some inherent capacity to respond to natural variability in climate, the ability to acclimate to larger future changes will vary by species and also relate to factors such as how and how quickly the species propagates. A forest stand’s capacity to respond to climate variability also relates to the stage of stand development.

Monitoring of resources can help managers detect changes and potential problems. Even so, managing ecosystems in the face of climate change will take initiative and determination because multiple different climate change impacts can occur simultaneously or sequentially.

The ability to project impacts depends to some degree on the quality and resolution of climate projections. While an increase in temperature is a robust projection, the arguably more important changes in precipitation remain challenging to project for a region, much less an ecosystem. At the same time, it is clear that the temperature changes alone hold the potential to reduce the length of snow season in many areas. This, in turn, has been leading to a predictable lengthening of the fire season. Some insects also are responding to shorter winters, including many species of forest-attacking beetles.

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Resources in this section:

• Biodiversity and Climate Change
• Soils and Climate Change
• Climate Change Impacts on Hydrology
• Climate Variation and Ecosystem Responses
• Multiple Ecosystem Interactions from Climate Change Impacts