Landscapes change over time. Any good landscape or permaculture designer, should foresee and account for those changes in their design.
It is important to consider factors which will impact on the change of the landscape including but not necessarily limited to: climatic or regional changes; seasonal changes; and, light intensity. Each of these must be considered in relation to the area that the system is based. Meaning that a system established in a humid subtropical climate will differ substantially from one established in a tropical savanna climate.
Climatic or regional changes
It is important to understand if and how there have been particular climatic or regional changes over time within the area designated for permaculture use. The combination of both flora and fauna inhabiting or able to live and perform well within an area will change according to the environmental factors impacting on that region. Accordingly, if the subject area is located in a region which has experience significant climatic change or is in the process of undergoing activity which will produce such change, it is beneficial to understand these processes and outcomes.
For example, if an area has seen considerable reduction in overstory tree coverage, as may be in the case of logging, bushfire, etc., the areas immediate and proximate to the reduction could be expected to experience an overall increase in soil tenuity leading to erosion and potential soil run-off following larger precipitation events, an overall reduction in soil health and decreased diversity of important microorganisms. These events may then lead to an overall reduction in plant and animal biodiversity across the region and/or an increase in the exposure of the area designated for permaculture. By knowing what has happened to the area and understanding how these changes have or will impact on the overall climate and health of the region, one can prepare for the resulting effects on the permaculture system. This understanding will support ones ability to prepare for and even utilise the process of natural succession within their permaculture system.
- Seasonal changes – plant flowers and fruits come & go with the years
- Soil changes – soils ban improve or degrade over time
- Light intensity – as plants grow taller shade can develop, air flow can reduce
Death of plants or animals can bring dramatic changes – when plants die; particularly bigger plants, microclimates change faster, and faster more significant changes can disturb ecosystems more dramatically than slower, gradual change. For example, when a large plant dies its remnants may collapse onto the ground, covering the earth and microhabitat below it, thereby almost immediately altering the microclimate. The coverage of the fallen tree or plant may reduce sun accessibility to the layers immediately below it while increase overall sun exposure to the area altering the microclimate of the surrounding zones. Additionally, different components left behind by the deceased plant will further impact on and prompt natural succession and its processes. For example, the root system left behind, the foliage or stems fallen to the ground, the nutrients no longer being taken by the plant. Each of these will have an impact on the immediate and surrounding areas of where the plant once stood.
When a major predator is killed, it can leave an environment vulnerable to invasion from a different predator. This concept remains the same at both an invertebrate and microscopic level impacting on the health and successive changes of the plants and soil within a permaculture system. For example, it is important to have a balance between the invertebrates and microorganisms residing within the soil of your garden beds and permaculture systems. For example, nematodes are important, often overlooked, bioregulators of soil health. Feeding on various fungi and microscopic organisms which reside within our soils their activity acts to regulate pest organisms and prompt biochemical conversion of various nutrients changing them into forms available for plants to uptake. A healthy presence of nematodes can contribute to ecosystem health through the control of significant pest insects, with their absence or removal then allowing an imbalance to ensue.
When structures are added or removed (eg. a fence), that can also introduce a more dramatic change.
Good permaculture design may demand more considered and graduated changes to a landscape to work with nature rather than shocking the working of nature. By understanding factors which affect the natural succession of an environment one can look to implement design systems and processes which work with the landscape and bolster a healthy ecosystem.