Marine Reserves as linked social-ecological systems

Figure 1 Showing the human effects on a food web before and after

Marine reserves are areas of ocean which are protected by law that prohibits any extractive activities such as fishing in order to preserve the marine ecosystems. Reserves are usually located in coastal areas near areas of large extractive activates. The importance of marine reserves only recently became apparent in the last few decades as fishing technology advanced to a point where by no part of the ocean was unfishable. When reserves were formed on previously highly fished areas it became obvious in just a few years how positive of an impact these areas can have. With no fishing allowed organisms were able to grow too much larger sizes, for fish this led to greater populations because the larger the females grow the amount of eggs they can release grows exponentially. Then with this increase in population it causes an ‘over spilling effect’ where by fish become too overcrowded and competition is made to high so they migrate out the marine reserves. This creates a constant supply of fish which fisheries can exploit without reducing the average size of any one species. However this fishing has to be sustainable i.e. not industrial trawling ships Fre 1 shows the impacts that people have on the complex food webs within marine environments which reserves attempt to reduce.

Some marine reserves are more effective than others and this may be due to the ecological variables of the area; as well as the socioeconomic views from the coastal colonies living within the reserves. This relationship has been explored on various occasions (however I will be focusing on the research carried out via Richard Pollnac et al. 2010). This research was carried out on 56 marine reserves in the Philippines, Caribbean and Western Indian Ocean. The ecological performance was compared by looking at the target fish biomass (which is the mass per unit area of fish that are exploited by fisherman living in a reef ecosystem). However this data is made relative to the outside of the reserve in order to give a better comparison and this is done by using the logged response ratio or InRR= in(inside/outside). Where by the inside and outside units is the mean fish biomass of each area. The outside areas that are measured are always close to the reserve on a similar habitat so to try and reduce variability of ecosystems.

Figure 2 Showing human environmental impacts on ecosystems

Socioeconomic variables were also taken into account in order to see whether there were any implications that affected fish biomass inside and outside the reserves. The variables taken account were the human population density of the coastal areas within the reserve and the compliance with the rules of the reserve. It has been usually suspected that reserves with higher or increasing population densities would show a negative ratio of fish biomass inside the reserve, as shown in figure one that shows just some of the implications of increasing human density in the surrounding communities. It was found however that it is area specific because the Caribbean was the only place to show this. This is because it was found that increasing population density had a negative effect in the Caribbean, a positive effect in the Western Indian Ocean and a non detectable effect in the Philippines implying that there were more variables than simply human density involved. One explanation given for the positive effect in the Western Indian Ocean is that people migrated around the reserve area due to the success of the reserve. This gave better fishing grounds around the reserve so drawing more fishermen to fish there. This over time dramatically reduced the fish biomass around the reserve so giving the relative positive result. This is one of the disadvantages with the data collecting method that the results can be shown to be positive but in fact the fish biomass as a whole could have decreased. For the Philippines it was later found that there had been very little change in population density so making it hard to make a clear cut relationship.

The more obedient the local government is with the reserves’ rules usually imply that there is a relatively higher fish biomass due to the strict lack of fishing and other extractive activities.However this was only found to betrue for the Caribbean as there was no effect in the Philippines and Western Indian Ocean. This may be due to the different ways in how each reserve is run. During the collection of data they foundthat the enforcement of the rules wasn’t as simple as first imagined. It was found that in fact the enforcement worked through a string of complex social interactions. This was more deeply looked into in a study concerning 127 marine reserves whilst looking at the contextual conditions of each reserve to determine if there was any correlation between social, cultural, political, economic conditions and the way the resources in the reserve are managed.   As seen in figure 3 enforcement is indirectly related to compliance where as the monitoring by the community and advisors is more directly related so in order for a reserve to be successful governments need to be investing in these indirect processes to ensure that the compliance increases.

Figure 3 Showing a Heuristic model between socieconomic consitions and compliance

Monitoring reserves from all around the world can be difficult because of the idiosyncratic methods that each area employs to track the progress of the reserve. Each therefore may give rise to different variables that another reserve may not have such as an unknown environmental factor which can affect the reserve’s performance. That’s why this research was carried out over across the entire social-economic gradient in order to give representation from all forms of economic regions and see how that effected a reserves resources.

Even though the focus of the research was on socioeconomic conditions and compliance other variables were taken into account. The boundary markers need to be placed strategically. This is because they are more than merely boundaries to the reserves; they have to be placed in an area where by a buffer zone can be set up around it. A buffer zone is the area around the reserve that has a socio-economic climate that is compatible to ensure the long term survival of the reserve. Marine reserves are much less common than land ones which is leading to Greenpeace campaigning for 40% of the oceans to be protected. The protection of migration paths and reproductive areas would lead to much better reproductive periods so increasing the marine animal’s populations, which would in turn improve the fishing industries productivity.

The reserve size and age are also good indicators to how successful a reserve is. This is because there it takes time for the effects of protection to be seen, this time is usually just a few years. A good example of this is a marine reserve in a New Zealand that over time went from bare rock environments covered with sea urchins to kelp forests in just 4 years. The size of the reserve can be a good indication because the larger the protected area, the more varying habitats are protected so giving protection to a wider range of species. The larger reserves also give rise to larger ‘over-spilling’ effects n the surrounding seas.

As seen in figure 4 the environmental impacts of human activities have impacted almost all parts of the ocean in some form. The most polluted areas are those in highly populated coastal areas such as the Caribbean, Japan and the UK. This is most likely one of the contributing factors leading to the fish biomass being negative in some of the Caribbean. If the oceans aren’t given the time to recover they may never return to the once bountiful and wide biodiversity that is already being lost in many parts of the oceans. Governments around the world need to employ more permanent means in protecting the oceans but like the areas researched the local participation is vital. This is because the compliance was measured through responses of resource users to see whether supplies were affected at all. This however was found to be bias in some areas in order to protect the resource areas they were exploiting so to take advantage of what resources were left.

Figure 4 Showing Global environmental impacts on the oceans

There will always be instances where by reserves can be totally destroyed due to freak accidents such as natural disasters or oil spills. However the rise in CO2 in the atmosphere will cause large scale bleaching of the oceans coral reefs which would lead to the biodiversity being greatly lowered. Bleaching occurs when the photosynthesising zooxanthellae leave the calcareous coral backbone due to the change in acidity in the oceans (due to he dissolved CO2 from the atmosphere making the waters more alkali). However this is just a defence mechanism corals employ during times of change in order to select zooxanthellae with more alkali environmental limits. However this can take a lot of time for the right type of zooxanthellae to come along so potentially leaving a habitat dead for many years.

There have been many examples where by the rules of reserves have been ignored such as in 2004 during the fisherman protests in the Galapagos islands. These protests were ended peacefully but not until many half promises were made allowing the regulations of fishing to be weakened that were carefully balanced in 1998. This allowed for Fishermans quarters to be increased meaning more fish could be caught in the reserve. This was stopped later in the year however due to many complaints about the changes in the regulations.  Whaling is another good example where by an industry, which in this case is a huge multibillion dollar industry, is unsustainably ridding the oceans of a vital part of food chains which has huge knock on effects down the niche. One of the most worrying facts is that it is estimated that 90% of all shark populations have been wiped out and at rates like this it has never been more evident that a sustainable option has to be made before the resource is gone forever.

“How is the ecological performance of marine reserves related to socio-economic conditions in neighbouring coastal communities” and “What social economic and contextual factors are related to high levels of compliance with reserve rules” were the main research questions explored. All three areas showed negative and positive results but the overall trend was that there was a higher fish biomass relative to outside the reserve with a 95% confidence. When it came to predicting the relationships between regions it was found that population density and stated compliance are the best forms of comparison. The success of marine reserves is undeniable and the push for more marine reserves to be set up is underway; however these are not just to be set up around coastal areas but in large areas of Open Ocean were the majority of the damage is occurring.


Figure References

12 years ago

Leave a Reply