Category Archives: Permaculture landscape architecture

Biodiversity management in Permaculture

The term Biodiversity encompass 3 perspectives;

– The number of species
– The genetic diversity
– The ecosystems variations

These 3 perspectives are 3 different paradigms with different natures, epistemology and complexities.

A species is the set of animals having the capability to interbreed and give life to fertile offspring. Bacteria species definition is different because of their character asexual. Viruses are excluded as well due to their specific nature.

Genetic diversity is the variation in alleles of genes within and among populations of individuals.

Ecosystem diversity is the variation in the complexity of a biological community. It represents the largest scale of biodiversity due to its systemic dimension. Complexity emerging from the multitude of relationships between the elements, biotic and abiotic.

The main focus in Permaculture is the ecosystem diversity, the relationship between elements being more important than the elements themselves. However the design of the domestic part of the ecosystem relies on the knowledge of the species introduced or attracted taking into account their specific functions and behaviors.

The design of the domestic biologic community in Permaculture may be influenced by

– The cost, capability and quantity of individuals of a species to fit inside a specific sub-ecosystem (adapted niches and schedules)
– The number of functions and positive interrelationships a species may have within the sub-ecosystem (positive relationships includes collaboration with productive elements and competition against counterproductive elements)
– The autonomy (including breeding) of the species (reduction of human monitoring)
– The opportunities the species may bring (food or resources production)
– The architecture and the potential niches of the ecosystem
– The permeability and ecotones between the sub-ecosystems and in particular with Zone 5

In every of these considerations we must have conscience of the possible lack of knowledge and the necessity to step in very carefully every time we introduce a new species.

The mechanisms at play in biodiversity related to the species and their environment are;

– Speciation : mechanism of life differentiation through evolution. (specialization, adaptation to a niche, emergence…) Mobility of a species and time spent in a specific environment are the two predominant factors of speciation
– Extinction : due to niche change, competition with more adapted species, food chain or food web perturbation (new predators, diseases, lack of food and resources, …)
– Migrations : immigration of new species in a specific ecosystem, emigration to other ecosystems .

Here are some drives in the construction of a biologic community in Permaculture;

– Use local species (species found in local ecosystems similar to the type of climax we may direct our ecosystem to).

– Limit the organisms introduction to few individuals at start and observe the group evolution and the impact on the environment. The early identification of niches allows as well to monitor the best ratio population size / allocated area.

– Time of reactivity after the emergence of an invasive species (extinction hosting) is an important factor to consider in order to reduce future maintenance.

– By favoring the introduction of perennials plants and large elements (trees) we facilitate the control of possible invasions (e.g. competition against grass or easy management of invasive perennials due to their slowness of propagation), multiply the number of niches (3 dimensional ecosystem) therefore the number of species (speciation hosting) and introduce a factor of stability favoring species settlement on the long term.

– Permaculture farms usually gives a preponderant role to aquatic ecosystems by their capacity to distribute water, produce resources and increase biodiversity both in the aquatic ecosystem itself and through its interface (ecotone) with connected ecosystems . Water ecosystems plays an important role in wild life attraction therefore biodiversity through natural (im)migration.

– Acceptance of balance in the impacts. A recent studies showed an increase of plants health in an ecosystem after bear introduction. The animal being a predator of ants themselves impacting negatively plants through different type of fungi culture. If introducing a bear in urban Permaculture for example is maybe not the best idea other examples can be found where accepting some impact can open bigger opportunity in the global balance.

– Increase the variations inside and in between species to enlarge the scope of opportunities. E.g. Having different fruit trees species or varieties spreads production over time.

– Get inform about or test the settlement of guilds.

– Resources about the benefits of biodiversity in ecosystems functions (services) :http://en.wikipedia.org/wiki/Biodiversity#Services_enhanced_by_biodiversity

Designing the Forest Succession

When conducting the process of reforestation we may consider two kinds of trees;

The support species, in charge of creating the nurturing framework of the forest ecosystem (soil fertilization through nitrogen fixation with leguminous plants, strong root penetration for soil breaking, nurturing and ventilation, rapid biomass production for mulch production and topsoil reconstitution, wind breaking and moisture capture, etc.) and

The productive species, in charge of food production for human and animals and side products generation like timber, fibers, etc.

At start 80% of planted trees, bushes and cover-ground are leguminous (support species) in order to boost the ecosystem capability to develop, and 20% of productive species are planted taking into account their capacity to adapt and resist to the first years of a non fertile and often dry environment. The support species are planted in various sizes and  over-density and will be pruned or removed over time to produce mulch and allow productive species to receive light.

How to proceed in term of design

80% of the support plants, mainly leguminous, will disappear, either naturally or pruned or removed, to create mulch and biomass.

The design needs to show on paper the species that will stay in fine in the food forest. They are mostly productive species and 20% of supportive species (for fertilization, wind break, mulch production, etc.) The location per zone of the different productive trees needs to be defined.

Then if the support species can be spread in the field surrounding densely the productive species they don’t really need to be included in the drawing since they form a nurturing placenta evenly distributed.

The distribution of support species may be compared to the construction of a grid, mixing homogeneously the different supportive species in size and shapes. Later the landscape architecture will operate negatively and remove the unnecessary plants.

It is on one part; classical landscape drawing, in the other; design by negative space in the landscape architecture. The supportive species which will remain (not been removed) are plants with particular positive interaction, health and robustness and capability to act as a permanent species, in size, shape and adaptability (pruning recovery, propagation capability, weather adaptation, …).

In Time

With regard to the time scale it is to be considered that some (most ?) productive species have poor pioneering qualities and will be able to settle only after a buffer of time, requiring the protection and the fertilization from pioneer species.

In this case either you have resources and may invest for each plant enough organic fertilizer, enough labor (modify the soil texture at the plant location if necessary), enough biomass to ensure global moisture and carbon availability, enough money to invest in infrastructure, e.g. “Groasis Waterboxx” See external resource.

or you may schedule the plantation following some strategies;

– Pioneer productive species are planted at the same time than the support species, at start of the reforestation . They will not grow quick but will resist and settle, ready to use in the future the resources provided by the support species.

– Productive species will be planted following a calendar based on their need for fertility, humidity and protection and on the resources available. The calendar is based on global fertility of the land improved over years by the support species and on the different specificity of the various location (An outdoor shower will provide with constant humidity, an existing tree will protect from the sun, a roof may concentrate rain falls or help to water zone 1 by rain water harvesting, etc…). Resource location (swales, pond, compost, chicken tractor, dry toilets, etc.) is as well key in the way to orchestrate plantation over time.

– Recent studies show that reforestation at large scale is better done by planting clusters of trees and not spread them homogeneously. The many small forests will nurture their close environment and help the settlement of trees in their peripheries, till the clusters extend and reach each others. As an habitat for seed gathering animals the tree cluster will support biodiversity in the forest propagation.

In space

A domestic variant of the cluster distribution is to stretch vegetation in strategic directions once settled. Various techniques can apply;

– If you have the capability to harvest branches and leaves (3rd / 4th year) you may over-stack the soil in between the sun course and the tree cluster, close to it, with pruned material. The material must be 1 meter high ideally and will protect the young seedlings from the sun and represent a reserve of biomass fertilizing the soil and keeping moisture. The presence of the tree cluster will provide with fertility on its periphery and wind absorption.

– On the other side, where the shadow of the tree cluster bring humidity and cool down the temperature seedlings do not need a lot of attention and no mulch is needed. The growth is the most reduced where the shade is the most intense.

Other fountains of resources (gray water treatment, swales, dry toilets, stable, ponds, etc.) can see their flow orientated in order to nurture vegetation extensions. In this case the slope play a determinant role associated with the sun course.

In all cases the prevailing wind and wind sectors need to be taken into account in the stretching directions.

Knowing the result in space and time of the stretching process for every tree cluster or resource fountain, this knowledge can be used to anticipate the design and influence the location of the resource fountain and tree clusters themselves.

New plantations are done at the start of the humid season. Exception can happen for zone 1 where watering can be done easily.

Flora

Leguminous species

Large : Acacia Mangium (see reforestation with Acacia Mangium)…

Middle size : Inga Edulis, Leucaena, Samsao do campo…

Small size and vines : Pigeon Pea, velvet Beans, Jack beans, Crotalaria…

Cover-ground (perennial) : Amendoin Foragera…

Some pioneer productive plants:

Mango, Jackfruits, Acai, Coconut trees, Dende, lemon tree…

Plants needing a fertile soil:

Banana trees, papaya, amora, goyava, caja, graviola…