Disruptions to Ecosystems - Detailed Notes
Disruptions to Ecosystems
Overview of Ecosystems
Ecosystems constantly change due to various factors:
Geological
Meteorological
Anthropogenic
Biological
Biological Factors
Evolutionary Impact
Changes to ecosystems drive the evolution of species.
Random mutations may lead to adaptations, making species more suited to new selective pressures.
Geological/Meteorological Factors
Natural Disasters
Examples include:
Volcanoes
Hurricanes
Floods
Wildfires
Significant changes to ecosystems following disruptive events.
Ecological Succession
Definition
Ecological succession is the process by which an ecological community changes over time.
Types of Ecological Succession
Pioneer Species:
First organisms to colonize an ecosystem.
Examples: Lichens, weeds, moss, grasses.
Function: Break down rock to create soil over time.
Intermediate Community:
Characterized by:
Grasses
Shrubs
Fast-growing mature trees
Young slower-growing trees.
Climax Community:
End point of succession; a fully stable ecological community.
Characterized by fully mature slow-growing trees.
Example: Old-growth forest.
Primary Succession:
Occurs when a land area is created or exposed for the first time.
Characteristics:
No soil initially present.
Takes a long time to develop (hundreds of years).
Examples: Receding glaciers or volcanic eruptions in Hawaii.
Stages of Primary Succession:
Initial colonization by pioneer species on bare rock.
Development of soil over time by lichens and annual plants.
Transitioning to grasses and perennials, intermediate species, and finally climax communities.
Secondary Succession:
Occurs when an established community experiences disturbance but soil remains.
Characteristics:
Relatively quick community rebuilding.
Example: Forest after a fire.
Stages of Secondary Succession:
Immediate colonization by pioneer species.
Development of intermediate species up to a climax community.
Geological/Meteorological Events
El Niño and La Niña:
El Niño increases warm, wet conditions; La Niña generally leads to cooler, drier conditions.
Both affect weather patterns, influencing ecosystems.
Anthropogenic Factors
Climate Change:
Leads to phenomena including:
Increased droughts
Altered species distribution.
Direct impact on coral reef ecosystems.
**Effects on Coral Reefs:
Climate change causes:
Rising ocean temperatures.
Sea level rise.
Ocean acidification.
Impacts:
Coral bleaching, increased diseases, reduction in growth rate and structural integrity of reefs.
Species and Diseases:
Climate change causes shifting distributions of species and disease vectors like Aedes aegypti, which can lead to increased transmission of diseases such as dengue.
Invasive Species
Definition and Impact:
Invasive species outcompete native species for resources.
They typically lack predators in their new environments, leading to unchecked population growth which disrupts existing food webs.
Examples of Invasive Species:
Not all non-native species are invasive, e.g., certain agricultural crops.
Negligent dumping of pets, like aquarium fish, contributes to species invasion.
Global economy has accelerated the spread of invasive species.
USDA Definition of Invasive Species:
Non-native to the ecosystem.
Causes or is likely to cause economic/environmental harm or harm to human health.
Takeaway: Understanding the various factors that disrupt ecosystems, including natural events and human activities, is essential for implementing conservation efforts and managing ecological health.
Recommendations to Help Ecological Health:
Reduce carbon footprints by driving less, recycling, and conserving energy.
Support sustainable practices in agriculture and seafood choices.
Participate in local conservation efforts and maintain good reef etiquette when visiting marine environments.