Management strategies must be adaptive in order to respond to possible future changes of drivers, growing evidence of external pressures, interactions and non- linear dynamics. Targets might need to be revised and policy instruments strengthened.
Any management strategy must be able to respond to future developments and new information. There are several possible ways in which future develop- ments and new information can influence what has to be done in order to meet the environmental objectives, and thereby the possibility and cost of reaching these.
First, if there is reason to believe that one or several of the drivers targeted by the management strategy (e.g. agricultural production, shipping, fishing) will increase in the future, it will be important that the strategy is capable of handling such a possibility. This emphasizes the need for a management strategy, which, when confronted with changes in the drivers or new informa- tion (regarding e.g. the effect of a measure), can adapt in order to make sure that the environmental objectives are reached. For example, in order to not exceed the targeted nutrient load to the Baltic Sea, more measures might be required due to an increase in agricultural production. In order to take account of possible future pressures holistic scenarios as regards the develop- ment of significant drivers can be of help.
Second, management strategies must also be capable to deal with so called moving targets. The targets, and thereby measures, required for meeting the environmental objectives might change due to:
• Faster increase of external forces (e.g. climate change) than expected. • Interactions that are not covered by the management strategy or yet not
completely understood (e.g. eutrophication-invasive species)
• Feedback mechanisms that accelerate undesirable changes and the risk of regime shifts.
Regime shifts
Natural systems change constantly, even with minimal pressures from human activities. However, there is growing evidence that human activities are causing pressures to ecosystems that could lead to regime shifts, pushing the systems into a whole new state. There is still much to learn about recovery and options when thresholds have been surpassed.
Recent research shows that even if measures are taken to reverse a negative development of state (e.g. depletion of fish stock, increased primary produc- tion), it will probably take time for these to recover. Furthermore, as illustrated in Figure 11.6, one cannot be certain that the ecosystem (response variables) will fully recover (green curve), the recovery might be partial (orange curve) or in worst case it might not be possible to recover at all. Examples from different parts of the world show that ecosystems that have undergone regime shifts may not return to the original state even if pressures are reduced to the
original level (Lotze et al., 2011). These examples often show patterns of only partial recovery.
One example with no recovery at all is the overfishing of cod (Gadus morhua) outside Newfoundland, which led to a collapse in the early 1990s. Despite a fishing moratorium no significant recovery has been seen up to date. (Hutchings & Reynolds, 2004)
Figure 11.6. Recovery can be measured as the magnitude (arrows), rate (slope) and time of
increase (or sometimes decrease) in a response variable, and compared to the magnitude, rate or time of previous depletion or degradation. Note that ‘no recovery’ could also consist of further decline or degradation.
As regards the Baltic Sea one could envisage that, for instance, the invasion of some new invasive species might be irreversible in that once they have established there are no ways to get ride of them. Also, changing conditions of the Sea, in combination with pressures such as overfishing, may lead to irreversible extinction of present species.
Modelling done at the Baltic Nest Institute indicates that eutrophication may be a problem for which it is difficult to reach a full recovery. Figure 11.7 illustrates the relation between phosphorus load and primary production (and thereby probability of algae blooms) in the Baltic Sea based on data from the period 1850–2006. It seems that in the 1980’s a threshold may have been surpassed after which reductions of phosphorus loads did not lead to any reductions of primary production.
Figures 11.7–10. Relation between phosphorus load and primary production in the Baltic
Sea based on data from the period 1850-2006 and modelling estimates 2007-2100. (Source: Unpublished figures, Bo Gustafsson, BNI (see also Gustafsson et al., 2012))
If phosphorus loads would remain at the same level as in 2006 primary pro- duction would develop as illustrated in Figure 11.8, where the blue line indi- cates predicted levels. As can be seen, there is not much of recovery as regards primary production up to 2100. However, if the phosphorus load is reduced somewhat more after 2006, a significant effect on primary production is pre- dicted as illustrated in Figure 11.9 and 11.10. Although, compared to the 1950s there is still not full recovery. Figures 11.7-11.10, thus, illustrate a case of par- tial recovery, in that even though the phosphorus loads have been reduced to a level corresponding to the 1950’s, the primary production is still higher compared to that time as illustrated in Figure 11.10. An interesting observa- tion is that the figures indicate that there may be thresholds also regarding actions to reverse negative developments.
Since changes in the state have implications for the benefits derived, high welfare values may be at stake if there is a risk of regime shifts. It seems that this is the case regarding the benefits to human societies provided by the Baltic Sea. Furthermore, the dynamics of ecosystems can be slow. In connec- tion to problems with long time spans between pressure and effects, such as is the case of eutrophication, invasive species, hazardous substances and to some extent oil spills, observations in the ecosystem as a basis for adaptive governance will not be satisfactory. Therefore, monitoring and developing
Figur 11.7 Figur 11.8
models, which can help understand future effects of today’s actions, are necessary tools for developing adaptive management strategies. It is therefore important with a science-policy dialogue.
The challenge for policy is to develop management strategies that can take into consideration the possibilities of regime shifts and threshold effects. That is, avoiding passing thresholds, but also understanding what is required once a regime shift has occurred and whether it is even possible to reverse such a shift and recover. In addition, management strategies must take into conside- ration that there might exist threshold points with regard to the effect of measures on state, as illustrated in figures 11.7–11.10. Even if a full recovery is not possible there may be ways to manage transformation so that welfare values are not lost.
Management challenges
A management strategy must be flexible for several reasons. First, a future increase of drivers might imply that more measures need to be implemented in order to reach the targets. Second, the ecological objectives might require a revision of the targets (e.g. allowable catches, maximum nutrient load) neces- sary to meet the objectives (e.g. good ecological status) due to change of external forces, ecosystem dynamics/interactions, possible feedback mecha- nisms and risk of regime shifts. This could imply that more measures are needed even if there is no increase of drivers.
Management strategies must be adaptive in that they include the possibility to revise the targets and the policy instruments towards the measures required to meet those targets.
In summary, a deeper sustainable management strategy, aimed at building the resilience required to cope and adapt to change, may be needed to respond to possible future increase of drivers, growing evidence of external pressures, interactions and non-linear dynamics.