104
.'
0'· .
.... p....... """ ........ 0 .. ·· .. ·'0
.....
·· .. ······41·· •. :
Before
t
A.J. Underwood . M.G. Chapman
/
After
Fig. 6.2. A "Beyond-BACI" analysis of the potential effects of an environmental disturbance affecting
the numbers of some organism in the potentially impacted (filled circles) and three control areas. BACI
designs, i.e. in which there are data before and after the apparent impact and from the potentially impacted and control locations are important for detecting environmental problems. Replication of the
controls is necessary for valid conclusions to be made (see Underwood 1992, 1993a, 1994a for details).
An impact must cause an interaction, i.e. the change from before to after the impact is different from
natural changes over the same time in undisturbed control locations
Managers of attempted improvements in resources or conservation of deleteriously
affected species need to aware of the nature of appropriate information and the minimal requirements ,of measurements. The same realization is true for those responsible
for detection and estimation of the magnitude of environmental impacts from planned
developments or accidental releases of toxic chemicals. Dealing with ecological uncertainty requires recognition of how to eliminate it.
6.2.3
Life~liistories and Scales of Management
Sometimes, the scale of environmental changes due to pollution, disturbances, planned
developments, etc., are not known. It is therefore important to ensure that any subsequent investigation of the consequences be designed to cover the relevant spatial scales.
This almost always requires an hierarchical design of sampling that can allow analysis
at a series of overlapping spatial scales (see Underwood 1992, 1993a for details).
This does, however, raise the important point that management of any aspect of
coastal environments requires very careful consideration of the spatial scales of the
biological systems being managed. There may be planned developments of a localized
nature, for example, a marina or canal estate may be built on a small patch of the coast.
The area chosen, however, may be an important source of offspring supplying new individuals to areas of similar habitats far away. Some marine species disperse over enor-
.'
0'· .
.... p....... """ ........ 0 .. ·· .. ·'0
.....
·· .. ······41·· •. :
Before
t
A.J. Underwood . M.G. Chapman
/
After
Fig. 6.2. A "Beyond-BACI" analysis of the potential effects of an environmental disturbance affecting
the numbers of some organism in the potentially impacted (filled circles) and three control areas. BACI
designs, i.e. in which there are data before and after the apparent impact and from the potentially impacted and control locations are important for detecting environmental problems. Replication of the
controls is necessary for valid conclusions to be made (see Underwood 1992, 1993a, 1994a for details).
An impact must cause an interaction, i.e. the change from before to after the impact is different from
natural changes over the same time in undisturbed control locations
Managers of attempted improvements in resources or conservation of deleteriously
affected species need to aware of the nature of appropriate information and the minimal requirements ,of measurements. The same realization is true for those responsible
for detection and estimation of the magnitude of environmental impacts from planned
developments or accidental releases of toxic chemicals. Dealing with ecological uncertainty requires recognition of how to eliminate it.
6.2.3
Life~liistories and Scales of Management
Sometimes, the scale of environmental changes due to pollution, disturbances, planned
developments, etc., are not known. It is therefore important to ensure that any subsequent investigation of the consequences be designed to cover the relevant spatial scales.
This almost always requires an hierarchical design of sampling that can allow analysis
at a series of overlapping spatial scales (see Underwood 1992, 1993a for details).
This does, however, raise the important point that management of any aspect of
coastal environments requires very careful consideration of the spatial scales of the
biological systems being managed. There may be planned developments of a localized
nature, for example, a marina or canal estate may be built on a small patch of the coast.
The area chosen, however, may be an important source of offspring supplying new individuals to areas of similar habitats far away. Some marine species disperse over enor-