Diagrama de gerencia de ecosistemas

The need for ecosystem rehabilitation measures should be determined
in the ecosystem management planning process (see 1.1). This
should include an assessment of the health of the ecosystem and ananalysis of threats. This is usually carried out through ecosystem surveys
as described earlier. Experienced scientists can recognize the
indications of ecosystem degradation, for example, byidentifying:
• the absence of certain species which used to be there, or would normally
be there;
• the presence of other species which have invaded or predominate
under changed conditions;
• thehealth of sedentary or less mobile species – both plants and animals,
e.g. coral;
• an absence of user groups, e.g. nomadic herders or fishermen that
would normally benefit from ecosystem productivity;• pollution levels – air, water and soil; and
• a failure of ecosystem functions, e.g. hydrological controls.
Many species populations show cyclical variation, which may be
annual or may extendover several years. Some ecosystems show
even longer-term natural patterns of change. Comparison of previous
conditions (e.g. of forest cover through satellite imagery and aerial
photography) andcontinuing observation may therefore be
necessary. Care has to be taken not to misread indicators of ecosystem
health that may vary according to seasonal, yearly or other timerelated
cycles, or toprevailing climatic conditions. Time-series
observations for longer periods of time may be necessary. Loss of productivity
in agriculture and fisheries and the well-being of farming
communities canserve as socioeconomic indicators of ecosystem
health. Participatory rural appraisal (see 1.4.4) techniques can facilitate
the comparison of earlier ecosystem conditions with the present.
Theassessment of ecosystem health should consider the linkages
between the different components and issues. Techniques, such as
problem tree analysis (Figure 5), allow an easy appreciation of the
linkages....