Species need landscape features to shift at differing speeds.
Shifting Patterns in Time and Space
Some species depend on constantly and fairly rapidly changing circumstances such as the creation and loss of bare ground, changes in the inundation status of soils – drawdown zones around ponds for examples, or the slumping of cliffs and landslides. Many insects and spiders are associated with these short cycles of bare ground creation and revegetation – this explains in part why Brownfield sites are so important for invertebrates.
Other species depend on slower processes such succession from open ground, through scrub to woodland;, slow shifts in salinity at the edge of upper salt marshes, or slow shifts in hydrology as lakes silt up or rivers shift their courses.
Species that depend on a combination of habitat features – for example the parkland specialist invertebrates that need flower rich grassland, decaying wood and flowering shrubs; are of necessity dependant on the processes that enable these features to coincide at a certain time and place. But those processes are also inevitably going to mean that the combination of features will rapidly cease to coincide at a particular time and place, as scrub replaces grassland or the resource of decaying wood disappears.
This can also be the case with the direct impact of human activities. Past industrial activity created habitat features such as bare ground, rocky substrates, temporary inundation features, toxic soils. These are by their nature transient – indeed historic as some of the processes that led to their creation are now illegal!
This human activity (industry, agriculture, forestry, mineral extraction) mimicked to a certain extent the natural processes of habitat dynamics. These human activities provided a constantly changing landscape which species could move within, able to find suitable habitat within their abilities to colonise or re colonise.
Modern land use has effectively removed the processes which created this dynamic mosaic of constantly shifting habitat features. Landscape ossification would be a good phrase for what we have done.
Modern agriculture and forestry have adopted the philosophy of modern industrial production where efficiency is the primary goal to achieve highest production at lowest cost.
Natural dynamic processes are generally engineered out of the system, to maintain as constant and optimal conditions for product, crop or animal growth.
Natural variables such as soil fertility and hydrology are tightly controlled, and the growth of non-crop/stock biota is minimised as seen as either competing with the crop/stock or a threat to it (as a carrier of disease).
Natural processes such as succession, substantial changes in hydrology (shifting river channels), peat building, the effects of natural pathogens on habitat assemblages (the boom-bust relationship between parasite/pathogen and host populations) are also engineered out of the system for the same reasons.
Attempts have been made to use agri environment funding to support farmers and foresters to either tweak modern agricultural activities to benefit species, or to recreate traditional pre-industrial agriculture in the belief that these approaches will be able to provide species with the habitat features that they require. These approaches have become increasingly prescriptive, under pressure from auditors and politicians needing to demonstrate value for public money, rather than actual results of increasing populations of species.
CAP rules on eligibility for direct payments explicitly proscribe landowners wishing to allow natural dynamic processes from occurring on land in receipt of direct payments – through the ridiculous 50 trees rule and ban on encroaching vegetation.
20 years of the BAP
Conservationists have over the last 20 years attempted to identify and prioritise actions based on the identification of priority species and habitats, which has led to a focus on maintaining or creating habitats in what is regarded as an optimal but fixed state for priority species or what are regarded as optimal condition, mostly based on the presence of plant communities that are highly valued for a variety of reasons.
The focus on maintaining habitats or expanding them has also led to landscape ossification in that changes from one priority habitat state to another are prevented rather than encouraged. Again dynamics have been engineered out of the system. This has been reinforced by the overwhelming importance of AE scheme funding to support conservation management over the past 20 and especially the last 10 years.
So while many hundreds of millions of pounds of public money have been spent on agri environment schemes, the vast majority of species continue to decline or are only kept at levels from which they are vulnerable to stochastic impacts or external effects such as climate change or population growth.
With the new CAP regulation comes a consequent renewal of the Rural Development Plans across the UK and Europe. Do we have an opportunity to incorporate landscape dynamics into the new schemes? Can we bring landscapes back to life, de- ossify them and enable natural processes to start again.
Certainly much thought has been applied to developing approaches which enable floodplains dynamics to be revived, though this has only been actually applied in a very few places. Equally there have been approaches to developing dynamics in woodlands systems with wild Ennerdale being one example in England, and much more work going on in Scotland particiularly in the Caledonian pine forests.
Landowners will no doubt argue that money is needed to allow or even encourage landscape dynamics to operate, even assuming any would be sympathetic (well at least one is – the Knepp Estate) . It is more than just a question of money though. There is something intrinsically repugnant to farmers in allowing landscape dynamics to operate, because it is seen as bad farming practice. Education here is key, but also making it a condition of payment receipt will also be needed. Voluntary approaches are unlikely to be effective.
There will also be opposition from the Agro industrial complex as their interest is in maximising profit and therefore food production beyond all other interests. Strong arguments will need to be made as to why it is more important than food production.
The current approach to AE schemes is to pay area and capital payments. Both approaches could be beneficially applied to landscape dynamics. An area payment could be made to encourage processes such as succession, bare ground creation, accumulation of deadwood or wet woody debris, removing constraints on rivers and springs and changing the type, level and seasonality of grazing from year to year.
Capital payments could be made for the removal of engineered controls such as sluices, drains etc or for the creation of substantial areas of new habitat features such as bare ground, rocky substrates, or wetlands which are specifically designed to undergo succession.
However in general the philosophy should be to avoid engineering solutions, other than to set initial conditions, after which natural processes should be enabled to be the primary drivers of change. This is similar to but different from re-wilding approaches because the aim is not to remove human impact or action from the system, but to enable natural processes to operate alongside human activity.
It may be that trying to incorporate landscape change into modern Agro industrial systems is unlikely to be successful at least in the short term, and other land uses may provide more fruitful ground – land currently under industrial use or even land where residential development is going to proceed.
Indeed the valuable brownfield sites of today have developed precisely because once the initial conditions have been reset or enhanced through industrial use, after which natural processes were left in charge due to post-industrial abandonment. Nowadays this is not allowed for various reasons including health and safety, contaminated land rules, pressure to re-use land, and cultural reasons “tidying up”.
Incorporating land where natural processes predominate in new housing developments would also be challenging, as preconceived notions of what constitutes optimal greenspace tend to focus on “we’ll managed” spaces, with mown grass and planted trees. Again this means education both of the house-owning public but also green space and GI professionals.