In order to better understand the recovery process of temperate marine habitats and
species, Scottish Natural Heritage commissioned a literature review, leading to a framework
for assessing recovery potential, with a particular (but not exclusive) focus on features within
Marine Protected Areas (MPAs) which have been identified as having a conservation
objective to ‘recover’ or ‘conserve (uncertain)’. This will enable a consistent approach to
recovery (including the way it is defined and the goals for recovery) and will help to inform
and standardise the SNH approach to managing the species and habitats within MPAs in
order to maximise recovery potential.
A number of species and habitats of national and international importance have been
identified in the seas around Scotland through the Scottish Marine Protected Areas Project.
A number of these are classed as threatened and/or declining under OSPAR, and draft
conservation objectives for these features have been presented to the Scottish Government
by SNH and JNCC. However, where a ‘recovery’ conservation objective has been assigned,
further development of the potential approaches that could be followed for achieving this
objective is required. Approaches under consideration can be characterised as including the
reduction or removal of pressures and consideration of the extent over which management
might be applied in relation to the extent of the features within MPAs. However, a better
understanding of the effectiveness of these, and other, management options will enable
SNH to optimise their approach.
A review of the literature indicated a high degree of variation in the use and interpretation
of the term ‘recovery’. It is proposed that ‘recovery’ should refer to a process or
trajectory and ‘recovered’ should refer to an end point. Separate definitions of
recovery and recovered have been proposed for individual species, communities
(including biogenic species) and habitats.
Of the species, communities and habitats reviewed, many show limited recovery potential
and of those which could recover, the timescale for recovery is likely to be long (tens to
hundreds of years). There are examples of recovery, or indications of recovery, having
been achieved as a result of pressure removal.
Factors limiting recovery included anthropogenic influence, together with aspects of the
biology of individual species and communities and environmental conditions. Of key
importance is the scale of the disturbance, the degree of habitat
homogenisation/fragmentation, species removal and the longevity of physical
modifications to the habitat. Recovery is reliant on environmental and biological
connectivity between populations or species patches and on the suitability of the habitat
in terms of substratum type, depth, water quality and sediment quality. For some species
(particularly those inhabiting soft sediments), subtle change in the sediment structure,
consolidation, stability and chemistry are of importance. Superimposed upon this are the
life history traits of the individual species, which may or may not enhance recovery
potential. These include reproductive strategy and frequency, growth rate, longevity and
dispersal ability, coupled with biological interactions between species which may
influence the direction and timescale of the recovery trajectory.
A brief review of restoration techniques indicates potential for application to a limited
number of species, particularly bivalves. However, the long-term success is unknown and
restoration should not be attempted at the expense of other management to enable
recovery and/or prevent further decline.
Management should take account of both environmental and biological connectivity and
should aim to protect the interaction between populations and sub-populations (e.g.
sources and sinks of propagules). Therefore, management should be targeted at both
physical and biological processes and management may have to be applied between
MPAs and/or beyond MPA boundaries if recovery is to be achieved.
Management needs to account for direct (near-field) and indirect (far-field) pressures.