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Drone seeding and E-seeds sound exciting, but ecosystem restoration needs practical solutions


A drone drops a small wooden projectile with three spiral tails and a seed on the tip. It lands softly on the bare ground and sits there, exposed to the elements, until it rains. Then the moisture penetrates the wood fibers and the spiral tails begin to twist, slowly pushing the seed into the soil, where it will germinate.

The design of this incredible depth-seeking seed carrier, recently published in Naturewas inspired by the self-burial mechanism of some grass species, such as those of the genus Erodium.

According to the authors, these seed carriers, also known as E-seedscan be built in different sizes for different species and dropped by planes or drones to restore degraded ecosystems.

This bio-inspired engineering marvel has received a huge and well-deserved share of attention and praise.

But from a restoration practitioner’s point of view, it has logistical issues that can greatly limit its application on a large scale.

Unproven ‘game-changers’

E-seeds are the latest of many technologies being presented as “game-changers” for recovery.

Numerous private companies have entered the market with revolutionary devices (usually drones), claiming to restore ecosystems through planting billions of trees. Yet it is there to this day little evidence of their efficacy.

This fascination with shiny technological gadgets could divert scarce resources from practical solutions on the ground that will seriously affect our ability to restore degraded ecosystems worldwide.

Much of the world’s ecosystem has been damaged or destroyed as a result of human activities. Global initiatives, such as the UN Decade for Ecosystem Restoration and the Bonn Challengepromote international cooperation to restore 350 million hectares by 2030.

For decades, scientists and practitioners have been working on solutions to support and accelerate the recovery of degraded ecosystems.

Read more: Restoration of forests is often the responsibility of landowners. Here’s how to do it cheaply and well

Most seeds fail

Often the first step in initiating the natural restoration of terrestrial ecosystems is the establishment of native vegetation. Tree planting is a common approach but can be expensive on a large scale. Direct sowing is faster and cheaper, but also riskier.

For starters, seeds must reach the right spot in the soil to germinate and grow.

If seeds are spread on the soil surface by hand, tractor or drone (seed broadcasting), they can be blown away by the wind or eaten by animals. Even if they germinate, the seedling may dry up and die. As a result, most seeds will not become a plant.

Therefore, the penetration of the seed into the soil is key to increasing a seed’s success rate. In general, the larger a seed is, the deeper it can go. This is often achieved using precision seed drills, similar to those used in agriculture. These machines open up the soil, place the seed at a precise depth and cover it. The E-seed can achieve a similar result, making seed spreading ideally as effective as precision seeding.

Precision farm seeder used with native species in Western Australia.
Simon Pedrini, Author provided

Unfortunately, this approach poses two problems: scalability and logistics. First, the multi-step process required to produce E-seeds is unlikely to be scaled up to the many billions of seeds spread across thousands of species that we need to restore entire ecosystems.

Second, the tails of the E-seeds can easily get tangled together, causing the seed delivery mechanism to clog or release in clumps. The authors solved this problem by using the seed tray in compartments with a single E-seed. This stopped seed clumping, but significantly reduced the number of seeds that could be delivered on each drone flight.

This clumping seed problem is also common with native species, such as the grasses that inspired the design of the E-seed. A simpler, less technological solution currently used in restoration is actually to delete the tails.

This reduces seed volume for storage and delivery and improves seed flow through the planting equipment. In some cases, the removal of appendages can also be done improve seed germination.

Such approaches are not as spectacular as E-seeds dropped from drones. Yet, in most scenarios, they are the most cost-effective way to reintroduce native vegetation to a degraded site on a large scale.

Close-up of several brown and yellow seeds, most of them round
Native seed mix of Western Australian species.
Kingsley Dixon, Author provided

Effective, not flamboyant

Ecological recovery is an incredibly complex activity that goes beyond the establishment of vegetation.

It must take into account the complex and dynamic interactions of organisms and their environment, while considering the social and economic implications for local communities. Therefore, we need to approach ecosystem restoration holistically and not get carried away by the lure of shiny technologies.

Financiers with limited appreciation for the environmental and practical complexities of restoration are eager to embrace and invest in charismatic, but often unproven, technologies.

For example, a start-up focused on drone seeding released a An investment of 200 million dollarsdouble the amount the Australian federal government has earmarked for the environmental restoration fund more than four years. But the science has yet to show whether drone seeding on a large scale can work to rebuild Australia’s degraded landscapes and ecosystems.

We should welcome any attempt to improve the success of ecological restoration and promote the implementation of new technologies.

But new technologies must prove their value and usefulness. We need to focus on the most effective ways to restore native ecosystems, not the most flamboyant.

Read more: Australia could ‘green’ its degraded landscapes for just 6% of what we spend on defense

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