(HAO) Conservation and Preservation Lesson

Instruction

Earth's systems are interconnected and nowhere is this more apparent than the land-water connection.   When water on Earth becomes polluted, it often comes from the land. Most of the pollutants in water can be traced to the land. These sources of pollution are known as nonpoint sources of pollution are poorly defined and scattered. They are difficult to monitor and identify. Some examples of nonpoint sources of pollution are runoff, pollution, storm-water drainage, and atmospheric deposition.

The Mississippi River is an excellent example of a river that has a large amount of pollutants from the land.   Pollutants from the land, along the entire Mississippi River, flow into the river, which dumps into the Gulf of Mexico. In fact, 1/3 of the topsoil in the United States has been lost to the Gulf of Mexico. This soil often has high levels of pesticides and fertilizers, which has caused a dead zone in the Mississippi delta. Inorganic nutrients are necessary for plant growth but too much of a good thing (nitrogen and phosphates, again) can cause algal blooms and cultural eutrophication. These algal blooms eventually die when they run out of their limiting nutrients, which increases the numbers of bacterial and fungal decomposers, which use up the majority of the dissolved oxygen (DO) in the area, which causes hypoxic, areas of low oxygen, dead zones. 

The Value of Ecosystems

Ecosystems have a remarkable natural ability to regenerate, so they are considered renewable resources. The trouble occurs when users take more than the excess and deplete the breeding population.

 

Some people only value species if they provide a service or are worthwhile to them in some way. Others understand the intrinsic value of species. The value of natural species and ecosystems can be categorized as follows:

• Value as sources for food and raw materials
• Value as sources for medicines and pharmaceuticals
• Recreational, aesthetic, and scientific value
• Value for their own sake

An important consideration is that we do not know all of the instrumental values that every species can have for humans, so it is likely that there is a species that we think may not have a lot of value, but that is just because we haven't discovered the use for that species yet. For example, some very rare species in the rainforest, such as the rosy periwinkle, are used to treat various cancers. When vincristine and vinblastine are used to treat childhood leukemia and Hodgkin's disease, patients have a 99% chance of remission. Rosy periwinkle is not the only plant with anti-cancer properties: over 3000 plants have been identified as having anti-cancer properties.  

A cost-benefit analysis is a tool that is used to develop environmental public policy. To conduct a cost-benefit analysis, you must first examine the need for the proposed regulation and describe a range of alternative approaches. Then, you must give all costs and benefits monetary values, when possible, and compare them using a cost-benefit ratio. This step is the hardest because it is often difficult to assign monetary values to environmental processes or resources. Once the options have been weighed, a recommendation is made.

External costs are effects of a business process that is not included in the usual calculations of profit and loss. It is important to account for all, or as much as possible, of the costs and benefits of a project or regulation, so the cost-benefit analysis is taking everything into consideration. Unfortunately, external costs can be difficult to measure. For example, when extracting gas from the ocean, what is the worth habitat being disturbed in terms of the environment, tourism, etc.

Conservation and Preservation

Ecosystems have a remarkable ability to regenerate after disturbances, so they are considered renewable resources. Problems occur when users take more than is sustainable and deplete the breeding population.   Conservation is when we manage or regulate use so that is sustainable. Preservation ensures the continuity of ecosystems and species, regardless of their potential utility. Generally, when we preserve an ecosystem, we protect it from use.

In order to conserve resources effectively, we need to know how much use can be sustained without hurting the ability of the species or system to renew itself. To this end, we have come up with a term known as maximum sustainable yield (MSY). This is the highest possible rate of use that the system can match with its own rate of replacement or maintenance. To calculate the MSY, we need to know the carrying capacity of the population, which is the maximum number of individuals that the area can support, and the optimal population size, halfway to the carrying capacity. Any population size over the optimal population, will be subject to competition for resources so managers like to keep the population at the optimal size or a little over the optimal size.   Once the MSY has been calculated, managers set the total allowable catch (TAC). Some years, if a population is struggling to recover, the total allowable catch can actually be zero.   This is known as the resource being closed to harvesting. Managers also try to employ something known as the precautionary principle. When there is uncertainty as to whether something will harm the natural resource, managers should favor the protection of the resource.

If resources have been overused or degraded, we sometimes have to restore them. This process seeks to repair damage so normal ecosystem integrity, resilience, and productivity can return. We are so good at degrading habitats, that restoration has become a $70 billion industry.

The graph above is of the Atlantic Cod population. This fishery was not managed well and the fishery has collapsed, meaning that the population is so small it can no longer support a commercial fishing industry.

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