First Year Success: Keyhaven Natural Capital Scheme Exceeds Expectations
John Durnell, Director of Nature-Based Solutions at Hampshire & Isle of Wight Wildlife Trust, provides an update on the Keyhaven Natural Capital Scheme, the first Biodiversity Net Gain (BNG) and Nitrate Mitigation scheme in the New Forest.
It has been nearly a year since the launch of the Keyhaven Natural Capital Scheme, which we are managing on behalf of Kingwell to transform farmland into thriving natural habitat. The results have exceeded our wildest expectations—this may be one of the best first-year wildflower meadow establishments I have ever witnessed.
Overcoming Early Challenges
Despite challenging dry conditions throughout the spring and early summer, our careful planning has paid dividends. The deep mulch applied during hedge planting proved essential, dramatically reducing hedgerow mortality rates. We were also fortunate to have a supportive neighbour who watered significant portions of the hedgerow before hosepipe restrictions took effect.
Paradoxically, the extreme dry conditions worked in our favour for meadow establishment. While the soil's fertility levels were slightly higher than ideal on paper, the exceptionally low organic content combined with drought conditions kept vigorous grass growth to a minimum. This allowed our carefully selected herb species to germinate and establish with minimal competition—exactly what we hoped to achieve.
The Power of Seed Mix Selection
Our investment in an herb-rich seed mix has proven worthwhile. Rather than using an off-the-shelf mix containing 50-70% grass species, we specified a blend with significantly more wildflowers and herbs. This strategic choice has created the open, apparently "bare" sward that traditional farmers might view with concern, but which wildflower specialists recognise as perfect conditions for long-term meadow success.
Whilst these open areas might look unsuccessful, but they represent precisely the growing conditions that allow wildflower seeds to fall and establish naturally over time. This foundation will support decades of biodiversity growth.
There were quite a few pioneers from the previous arable crops, but this is not a concern, as they will tend to disappear over the next few years as the annual meadow species close the sward up. It is one of the best first years of sowing I have ever seen.
A Spectacular First-Year Display
The diversity and distribution of flowering species across the site has been truly remarkable. Even in this inaugural year, we are witnessing stunning displays of oxeye daisy and wild carrot. We have also discovered rare annual species like cornflowers. While these are a delight to see they may naturally diminish as perennial species mature and dominate.
Some of my personal highlights include:
• Bird's-foot trefoil: These charming yellow flowers serve as an essential food plant for common blue butterfly caterpillars
• Grass vetchling: While unremarkable when not in flower, its single red blooms suspended on long stems create the effect of rubies floating in mid-air
The Sound of Success
The overall success of the meadows is not just about the plants; it is also about the abundance of butterflies and bees. Walking through these meadows, you can hear them buzz with life, which speaks volumes about the habitats immediate ecological value.
Looking Forward: Building on Success
The key achievement is not just the impressive flower display—it is the high ratio of herbs to grasses we have established. This lack of competitive rank grasses creates ideal conditions for continued biodiversity development in the years ahead.
While pioneer species from previous arable crops are visible, these will naturally diminish over the next few years as our planted annual meadow species mature and close the sward. This is all part of the natural progression we anticipated.
A Model for the Future
The speed with which positive indicator species have established has been remarkable, and the spectacular flower displays have impressed both our team and local neighbours. More importantly, this success demonstrates the viability of nature-based solutions for achieving both biodiversity net gain and nitrate mitigation objectives.
As we continue monitoring this pioneering scheme, the Keyhaven project is setting new standards for what's possible when careful planning, appropriate seed selection, and favourable conditions align. It is one of the best years of sowing of a wildflower meadow the Hampshire & Isle of Wight Wildlife Trust has ever achieved. The high percentage of herbs (non-grass species) compared to grass is a really is a positive sign for the land in the future.