Ecological Function #4
Plants as Contributors to Ecosystem Resilience:
- Phenotypic plasticity and acclimation – Because environmental conditions change all the time, species have mechanisms for constantly adjusting their biochemistry, physiology, and growth/development – a phenomenon known as homeostasis. Plant scientists describe some of these adjustments as “phenotypic plasticity” (involving gene expression adjustments) and “acclimation” (involving physiological adjustments). Both types enable individual plants to “roll with the changes” within limits, helping the plant to respond to stresses and continue growing. For example, plant leaf shape and color depend on the intensity of sunlight: shade-grown leaves tend to be larger, thinner, and greener than sun-grown leaves. However, environmental conditions that exceed a plant’s ability to adjust will result in declining health or even death.
- Biodiversity and adaptation – Gardeners can think of biodiversity in terms of species diversity and genetic diversity. Species diversity (having many different species) enables an ecosystem to be more resilient in the face of environmental stress (heat, drought, flooding, disease, etc.). This is because different species have different tolerances for different stresses and because species interact with one another during the phenotypic plasticity and acclimation processes. Genetic diversity (having a large gene pool) enables a population of organisms (all belonging to the same species) to better adapt to environmental changes. This is because some genotypes (gene combinations) will be better fit for the new conditions, enabling those plants to thrive and reproduce. If these fitter plants can spread their genes within the population, then the entire population is more able to adapt to the new conditions. Corridors and connections between populations are crucial for spreading these fit genes throughout the area.
- Mutualistic relationships, especially with mycorrhizal fungi – There’s a lot going on underground between plants and microbes, especially with mycorrhizal fungi that live in and around plant roots. Long assumed to have neutral or negative effects on plant health, these fungi use their threadlike mycelia to form networks with plant roots. A growing body of recent evidence now demonstrates that these networks are used for positive interactions, including communication and nutrient sharing between plants. Some researchers have now dubbed this hot new field the “wood-wide web.” Over the past few years, additional studies have explored this web’s potential for helping plants deal with herbivores, pathogens, and abiotic stresses (including drought and heat). Early results suggest that most plant species are capable to interconnecting via this web and that the web is useful for stress acclimation. Clearly, we have a lot to learn yet about the social life of plants!
Implications for Gardeners:
- Recognize that phenotypic plasticity and acclimation adjustments do take place on an individual basis, with some plant varieties capable of a broader range of adjustments than others. When deciding which varieties to plant, look for information about tolerance for cold vs heat, sun vs shade, and wet vs dry conditions.
- Increasing species biodiversity in one’s garden helps to improve its resilience to climate and other ecological changes.
- Increasing genetic diversity in one’s garden and providing connections (such as pollinator corridors) to neighboring gardens can help a species to adapt to new environmental conditions.
- Nurturing biotic soils to support mutualistic relationships involving underground mycorrhizal fungi may prove essential as plants deal with multiple environmental stresses at once. This will likely entail the formation of underground networks between neighboring plants (even between different species) over long periods of time (years). Minimizing soil disturbance will help with this.
1-Diversifying for the future
2-Focusing on ecological functions
Food
Protection
Regulation
Resilience
3-Fitting the natural landscape
4-Co-creating with nature
5-Cultivating relational caring
Refugia Gardening 