Natural succession as a restoration tool ― Editorial

Ecosystems are continuously being serverely damaged by human activities, and we are now beginning to understand that these changes often disrupt ecological processes that we rely on.  Thus ecological restoration is becoming increasingly critical.  Practitioners of ecological restoration often use technical means, including the use of heavy machinery and large amounts of manual labor, to restore biodiversity to damaged areas.  This is often very expensive; nevertheless we must find a way to rehabilitate the overwhelmingly large amount of damaged ecosystems throughout the world.

In ecological restoration we are concerned with increasing the natural value of degraded areas.  Apart from technical restoration, changes within ecosystems occur through natural succession.  Often a primary goal in restoration is to increase the cover- and diversity of vegetion.  One doesn't expect to see these increases, at least not through natural succession alone, at sites which are extremely toxic or dry.  However, one could use technical restoration methods until the plant community becomes capable of continuing the succession process on its own.  On steep slopes, or other areas where the threat of landslides or erosion is great, re-vegetating the site as quickly as possible is clearly justafiable; and faster formation of continuous vegetation cover is a common advantage of technical restoration methods.  A study looking at erosion in Fujian Province, China, indicated that 20 % vegetation cover represents a restoration threshold, beyond which natural succession can be embraced.

A number of scientific investigations by Czech biologists suggest that leaving Czech post-mining sites to undergo natural succession can be beneficial for aquatic- and terrestrial communities.  Amphibians benefit from natural succession in these areas, as this process creates many small shallow ponds, rich in vegetation, throughout the landscape; while sites which are reclaimed by technical methods are typically flattened and contain only large deep ponds which are vegetated only within the riparian zone, and contain predatory fish.  Sites where natural succession prevails often represent various stages of succession, called seral stages; and landscape-scale studies have indicated that a greater diversity of seral stages tends to increase regional biodiversity.

Strategically embracing natural succession as a restoration tool can save time, money, and effort, and lead to more-diverse ecosystem development.  At many sites, technical measures may be necessary to prevent- or remediate extreme environmental damage.  Of course, there are countless degraded sites at which biodiversity can re-develop from natural succession alone.  At countless other sites we can surely find a balance between technical restoration methods and the strategic use of natural succession; this balance would be specific to the restoration site in question.  A limited-intervention approach has been suggested for wide use.  This limited-intervention approach involves assessing limiting factors for a particular site's development, leading to a restoration approach using the minimum effort required to meet specific restoration goals.  Additionally, as long-term monitoring remains one of the largest let-downs in conservation science- and practice, this approach may help the field move forward by allowing more-robust monitoring efforts due to the money saved on restoration methods.  Considering the amount of terrestrial- and aquatic habitat that currently requires restoration, the limited-intervention approach may be the wisest and most feasible option.