Plant Ecology Notes

Plant Ecology Definitions

• Ecology: Study of organism interactions with each other and their environment.
• Plant Ecology: Study of the relationships between plants, and biotic & abiotic environmental factors.
• Biotic factors: Living things and their interactions.
• Abiotic factors: Non-living things and their interactions.
• Biome: Large environment characterized by abiotic (temperature, precipitation) and biotic factors (plant communities, wildlife).
• Biomass: Weight of living/dead organic matter in a given area.
• Ecotone: Transition zone between habitats.
• Ecological succession: Change in species structure of an ecological community over time.

History of Plant Ecology

• Emerged as a Western scientific discipline in the 19th century.
• Alexander von Humbolt's research led to synecology (study of plant communities).
• Indigenous Peoples have long understood plants as interconnected with other life forms.
• Ernst Haeckel coined the term “ecology” in 1866.
• Darwinian approaches became popular to understand plant adaptations to different environments.
• Henry Chandler Cowles investigated plant community succession.
• Frederic Clements viewed a plant community as a 'complex organism' with predictable development.
• Population genetics in mid-20th century led to identification of ecotypes (ecological varieties of species).
• Arthur Tansley proposed the term "ecosystem".
• Genomics is now integral to plant ecology, aiding understanding of plant adaptation to climate change.

Ecological Scales and Biomes

• Biome: Large environment with specific abiotic and biotic factors.
• Tundra: Coldest biome with little precipitation, poor nutrients, and short growing seasons.
• Taiga: Cold, subarctic forest with short growing seasons and coniferous trees.
• Temperate Forests: Mid-latitude forests with high precipitation and humidity; broadleaf trees.
• Steppe: Dry, grassy plains in temperate climates with semi-arid conditions.
• Mediterranean Vegetation: Climate with dry summers and humid winters; woodlands and shrublands.
• Tropical Rainforest: Hot, moist biome with high rainfall and diverse plant/animal species.
• Desert: Driest biome with very little rainfall and ground-hugging shrubs.
• Savanna: Hot, seasonally dry with open tree canopy and dominant grasses.
• Montane: High-elevation grasslands/shrublands with alpine climate and mixed forests.
• Intra-biome communities exist within biomes, driven by geology, altitude, and local climate.

Cryptogams and Biocrusts

• Cryptogams: Account for significant carbon and nitrogen fixation.
• Lichens: Symbiotic associations between fungi and algae/cyanobacteria, forming mini-ecosystems.
• Biocrusts: Communities of organisms on soil surface in arid/semi-arid ecosystems, including lichens, mosses, and cyanobacteria.

The Holobiont Concept

• Holobiont: A host and its associated species forming a discrete ecological unit through symbiosis.
• Plants are holobionts, comprising the plant itself and its associated microorganisms.

Symbiotic Relationships

• Symbiosis: Two or more species living together.
• Mutualism: Both partners benefit.
• Commensalism: One benefits, the other is neither harmed nor benefits.
• Parasitism: One benefits at the expense of the other.

Plant-Microbe Interactions

• Plant-soil-microbe interactions affect plant fitness and gene expression.
• Plant-microbe-pollinator interactions occur during pre-pollination, pollination, and post-pollination stages.