Unit 6: Drivers of Ecosystem Change
Introduction to Unit 6
In this unit we will be listening to a presentation by Dr. Nancy Shackelford, Director of the Restoration of Natural Systems Programs and ES Faculty at UVic.
The purpose of this unit is to understand:
- The many different influences of natural ecosystems around the globe
- How these ecosystems are responding to these influences
Learning Objectives
After successfully completing this unit, you will be able to:
- Examine complexity of ecosystem responses to change agents.
- Determine how individuals might assist in the recovery of ecosystems in their areas.
As you watch and listen to the presentation, think about the following questions:
- What are the primary goals of management in your site?
- What are the social, ecological, or environmental changes you expect will influence these goals in the next year? Five years? Twenty?
- At what scales are these changes occurring? Within your site? In the surrounding landscape? Regionally or globally?
- What are the possible actions that you could take, as a manager, to mitigate the impact of these changes on your goals? Are there even ways to incorporate these changes into your goals?
Video attribution: “Drivers of Ecosystem Change” is licensed under CC BY-NC-ND 4.0.
Summary of Key Points
Major ecosystem drivers globally:
- Habitat loss and fragmentation
- Edge effects on altered ecosystems
- Invasion by introduced species
- Global climate change
- Human population increases
Key Points
- Restoration projects must consider the impacts of these key drivers on ecosystems at the landscape and site levels
- SER describes (8) key principles of ecological restoration
- Ecological restoration process can be treated as an ecosystem risk analysis: strengths/weaknesses/opportunities/threats on each restoration site
- Landscape scale and site scale factors should be assessed for each restoration project
- New examples of planning tools to apply to ecological restoration, such as Miradi
- Adaptive management involves active learning, data collection and monitoring
In Summary
Several major forces are at play in driving ecological change around the globe – the movement of invasive species; human land use patterns; habitat loss; and climate change. In combination, these drivers of ecological change are transforming the world as we know it.
Terrestrial ecosystem function is governed largely by the composition and physical structure of vegetation communities, and climate change impacts on vegetation can potentially cause disruption of ecosystem services and loss of biodiversity. Ecosystem transformation generally involves the replacement of dominant plant species or functional types by other species, whether recruited locally or migrating from afar. Climate change is interacting with movement of invasive species, changing fire regimes, changing land use, and increases in CO2 to drive vegetation changes in many regions of the globe.
Vegetation composition and structure are sensitive to changes in mean annual temperature (and precipitation) and vegetation transformations will become increasingly extensive as temperatures increase. Although many ecological responses (species migration, colonization and succession) will lag behind climate changes, ecosystem transformations will be accelerated by the other drivers of ecological change – changes in land use, movement of invasive species, and climatic disturbance events. Without reduced CO2 levels, terrestrial vegetation over the entire planet is at risk of major compositional and structural changes. Emerging ecosystems may be novel in composition, structure and function, and there may be replacement of dominant or keystone species, changes in trophic levels and changes in species interactions. Species biodiversity, habitats and resource use may change drastically (Nolan et.al, 2018, Science 361, 920-923).
What can be done from a resource managers’ perspective to respond to or adapt to these proposed changes? There is a need to maintain and enhance ecosystem biodiversity and complexity by protecting key ecological processes, diversity of species, and diversity of cultural practices. Management should be done at multiple scales to ensure this protection. Managers should look beyond species-specific prescriptions and practices, to ensure that ecosystem processes and functions are protected and enhanced. Without ecosystem functions and processes in place, no ecosystem services or products will result. Ecosystem resilience will be maintained by protecting the widest range of species possible, and connections between habitats and across landscapes, to allow these species to move and adapt to climate changes (Harris, et.al. 2006, Restoration Ecology 14, No. 2, 170-176.)
At the local level, citizens, volunteers and resource managers can take similar forward-thinking actions: protect and restore sites of rare and endangered species, and build ecological connections between these sites to enhance genetic movement. Protect not just species per se, but the processes and functions that produce these species, to ensure that the sites can become self-sustaining as ecological changes continue in light of climate change and other ecological drivers.