Letting our earth rest and breathe

Biodiversity is making its way up the investment agenda as a natural companion to Climate Change. The Taskforce on Nature related Financial Disclosures (TNFD) will mirror the path of adoption that the Task Force on Climate-Related Financial Disclosures (TCFD) has already proven, but how can we make sure we search out the opportunities and solutions alongside an appreciation of the risks?  

Downing’s Head of Sustainability, Graham Brady, outlines how renewable energy is elevating biodiversity in the investment ecosystem.  

While sitting in a fantastic session on biodiversity loss at the UK SIF Spring Conference recently, one of the top trending questions was "please could the panel comment on biodiversity positive investment opportunities?" The answer might be renewable energy but only if biodiversity is measured and managed.

 Measuring and benefits 

Renewable energy is meeting a well-understood environmental need, displacing emission-intensive generation from our energy consumption needs. We always mitigate damage to the natural environment and, beyond that, land planning applications almost always include an expectation of biodiversity net gain - but how is this measured?  

For the purists, it’s typically using the biodiversity metric 3.1 calculation tool, developed in partnership by Department for Environment, Food & Rural Affairs alongside Natural England. This lens focuses on habitat types, but underpinning any healthy habitat is healthy soil.  

 Healthy soil, healthy planet 

Intensive arable production, while feeding our growing population, comes with some acute environmental risks - poor soil health being one. Healthy soil is typically a balance of air, water, decayed plant matter, organic material and minerals such as sand, silt and clay. Some of the risks to soil health can be mitigated by adding synthetic and organic fertilisers but doing so can have negative effects on water quality and habitats. It's hard to mitigate the effects of soil compaction from the passage of heavy machinery like tractors and it's hard to avoid the carbon emissions from constantly turning over and exposing the top 30-50cm of soil.  

Long before humans developed synthetic fertilisers, crop rotation and ‘resting’ land was the remedy for poor soil health. However, there has usually been a short-term economic price for not maximising the productivity of the land. Renewable energy has an important part to play in compensating farmers while the land is rested from intensive production techniques - but how do we measure and manage the benefits to soil health? 

It's time to test 

Reducing the time that soil is exposed to the elements by protecting it with wild grass and flower mixes can meaningfully slow the rate of soil erosion. Simply hammering a stake into the protected soil and measuring the topsoil height over time can illustrate how wild grass cover is slowing and reversing the effects of soil erosion.  

A penetrometer measures the soil’s compaction or compressive strength in kilograms per square centimetre.  

An earthworm count is a simple exercise that requires nothing more than a shovel and preferably some small children to help count.  

You can test the water infiltration rate with a tin can full of soil, a small amount of water and a watch. This infiltration rate will tell us something about soil compaction, a bit about the balance of organic material and a lot about the soil’s ability to retain water. A soil slake test is equally simple and can be an indicator of biological activity and nutrient cycling in the soil. Cutting a cross-section into the soil will enable us to measure root depth and volume.  

All these techniques sit within the ecologist and agronomist’s toolkit, and we want to understand these effects too.  

It's easy to talk about the risks of biodiversity loss, but we can only start to manage the positive benefits for biodiversity and natural capital when we measure them. Having an easily used biodiversity calculation gives us a single number that we can plot on charts and manage improvement against over time but habitat loss and gain is only one aspect -we want to know what’s under the surface. We are farmers of energy and stewards of our landscape. 

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