PLANT ECOLOGY BSC305

What Do You Know about Plant Ecology?

• Open plant communities consist of open canopies with sparse vegetation and usually one or two canopy layers.
• Closed communities include more dense vegetation with a closed canopy. Closed communities may consist of rain forest plants and include larger leafed species.  

Lesson Structure

There are 8 lessons in this course:

1. Introductory Ecology
   • Definitions for ecology, ecosystems
   • Constituents of an ecosystem
   • Ecological concepts
   • Interrelationships between climate, soil and living things (consumers, decomposers)
   • The food web
   • Habitat and niche
   • Biomes
   • Terminology
2. Plant Communities
   • Open and closed plant communities
   • Habitat types
   • Location and characteristics of biomes
   • Semi natural vegetation
   • Competition
   • Succession of plant communities
   • Community stability and equilibrium
   • Environmental stress
   • Edge effects
   • Terminology
3. Plants and their Environment
   • Development, structure and function
   • Plant modifications: functional adaptions
   • Environmental factors: light, temperature, fires, wind
   • Monitoring abiotic factors
   • Introduction to Environmental assessment
   • Pre purchase inspection of a site
   • Background data
   • Flora and fauna surveys
   • Open space management plans
   • Compliance with licencing conditions
   • Detection of pollutants
   • Use of plants
   • Remediation of a polluted site
4. Plants, Soils and Climate
   • Natural conditions andplants distribution
   • Climate classification
   • Examples: climate in the UK, climate in Australia
   • Meteorological data
   • Plant distribution
   • Geographic location
   • Rainfall
   • Evaporation
   • Effective rainfall
   • Circulation features
   • The walker circulation
   • Southern oscillation
   • El nino
   • La Nina
   • GAIA theory
   • Carbon dioxide cycle
   • Wind descriptions
   • Soil problems
   • Erosion
   • Salinity
   • Soil structure decline and soil compaction
   • Soil acidification
   • Build up of dangerous chemicals
5. Plant Adaptations to Extreme Environments
   • Ecological groups of plants: hydrophyte, xerophyte, mesophyte, halophyte
   • Xeromorphy
   • Common environmental problems when growing plants: foliage burn, pollution, lack of water, frost, shade, humidity, temperature, wind, etc
   • Desert landscapes
   • Xeriscapes
   • Coastal gardens
   • Water plant environments
   • Greenhouse plants
6. Manipulating Plant Environments
   • Controlling environmental conditions
   • Tolerance levels for different plants
   • Matching plants with their environment
   • Managing light
   • Managing water
   • Protective structures
   • Windbreaks
   • Tree guards
7. Environmental Conservation
   • Water pollution
   • Soil pollution
   • Atmospheric pollution
   • Effects of horticulture
   • Pesticides
   • Fertilisers
   • Deforestation problems
   • Loss of agricultural land
   • Loss of biodiversity
   • Environmental weeds
   • The greenhouse effect
   • Other environmental problems affecting plant communities
   • Greenhouse gases
   • Ozone depletion
   • Introduction to recycling
8. Environmental Organisations, Assessment and Funding
   • Plant conservation
   • Conservation of individual species
   • Conservation organisations
   • Conservation funding

Aims

• Define the term ecosystem
• Explain the importance of plants as energy producers within ecosystems
• Explain basic ecological principles
• Define the terms open and closed plant communities, semi-natural vegetation, dominant species, climax association.
• Describe the effects of plant association and competition on the succession of plants
• Describe how plant communities respond to environmental stresses.
• Explain how the development, structure and function of an organism depends on the interaction of that organism with its environment
• Describe the effects of a range of abiotic environmental factors on plant growth and development
• Explain the importance of monitoring abiotic environmental factors
• Describe plant modifications to withstand extreme environmental conditions
• Describe the weather and climate in a particular region.
• Relate plant distribution, growth and natural selection to soil, geography, weather and climate.
• State how soil, geography, weather and climate affect the horticulturist’s selection of plants for any specific growing location.
• Evaluate the use of meteorological records in relation to plant growth and development
• Define the terms xerophyte, hydrophyte and halophyte
• Describe the structure and function of xerophytes, hydrophytes and halophytes
• Describe how xerophytes, hydrophytes and halophytes can be utilised in garden or landscape situations
• Describe the significance of xeromorphy in temperate zone plants and its importance in the garden or landscape situation.
• Evaluate the methods by which environmental conditions can be manipulated to improve the growth and development of plants
• Determine factors affecting the choice of plants for garden or landscape sites with extreme conditions
• Assess the value of using protective structures to grow plants
• Describe the sources and nature of pollutants and possible effects on plants
• Describe how the environment may be affected by a range of horticultural practices
• Explain how planning, environmental assessment and impact analysis may contribute to the conservation process
• State the major sources of grant aide available to support environmental conservation on horticultural sites

Learn How Plant Communities Can Evolve

Plant communities change over time in response to changes in the environment. The process of changes is called succession. Plant community succession leads through a sequence of different community types to a stable plant community suitable for the environment. The stable part of the succession is called a climax community.

Succession that started on a place where plant community was completely destroyed as a result of fire, volcanic activity etc. is called primary succession. If environmental impact didn’t kill the community completely (i.e. land clearing, climate changes etc) and some elements of the old community are participating in the succession, this process is called secondary succession. Successions caused by internal ecosystem factors like overgrazing etc are called autogenic successions. Allogenic successions are caused by external factors (flood, fire, land clearing etc).

After a big disturbance a ruderal community is formed. The plants in the community are pioneers that can tolerate harsh environmental conditions and can propagate and grow fast, but they are not very competitive. After a sequence of intermediate communities a climax community typical for the conditions is formed. A climax community can consist of competitors (in good environmental conditions) or stress tolerators. Understanding what stresses a plant helps you understand how to reduce problems and improve plant growth.

All plants experience environmental stress, but some plants respond better than others. Certain plants have adapted to particular environments to survive. For example, rainforest plants have adapted to low light situations by having increased leaf size to capture more light. Other plants have many natural responses such as dropping excess leaves in dry periods, so not to waste energy on leaf production.

THREE GROUPS

All plants are classified into three different groups by their adaptation and response to environmental stress: ruderals, competitors, and stress tolerators.

Ruderals
Ruderals, often called weeds, are plants that can survive very high level of environmental stress. They are the first plants to colonize open space after fire, flood etc, but replaced by better competitors when environmental conditions improve.

Competitors
Competitors can’t stand environmental disturbance very well, but they take over available natural resources in a communities without high level of stress because of their high ability to compete for the resources.

Stress tolerators
Stress tolerators are adapted to environmental stress of some particular kind like high salinity, shade in lower levels of forests, desert conditions etc.