THE LAND IS DIVIDED

          

          Could you imagine losing your home and having to find a new area to live in? This is one of the primary reasons of endangerment for several species that are currently losing their natural habitats. The Salt-Marsh Harvest mouse is an endangered species that is highly threatened right now because the majority of salt marshes have become fragmented, which impacts the entire ecosystem living there. Fragmentation can negatively impact species like the salt-harvest mouse that are dependent on large ranges on land to survive. Effects of fragmentation occurring include isolation effects on marsh habitat; making the species have an increased level of inbreeding, causing the offspring to have genetic abnormalities or not be able to adapt to the environment compared to its ancestors (The Wildlife Society, 2019). This means that about 84% of all historical marshes have been destroyed in the San Francisco Bay area due to increased fragmentation of the range. To prevent further fragmentation in marsh habitat from happening, buffer zones need to be implanted. These zones create areas around edge habitat that protect the interior habitat of the marshes from disturbances on land (The Wildlife Society, 2014).

 

THE BATTLE FOR THE MARSH

 

          The salt marsh harvest mouse is being forced to compete with the Microtus californicus (California vole) because the wetlands are shrinking and drying out. The California vole isn’t technically an invasive species since it is native to the region, but it is not native to the salt marshes (UC IPM, 2017). As humans destroy the grasslands that the vole once inhabited, they are being forced towards the wetlands. Since they are five times the size of the salt marsh harvest mouse, they quickly kick the smaller rodent out. The mouse then retreats to the very edges of the marshes, where they are more exposed and prone to drowning (Howell, 2013).

 

YOUR POLLUTANTS ARE DAMAGING

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          The increased amount of pollution that is produced from our cars, building corporations and non-renewable energy sources such as coal and oil, have all contributed to the number of greenhouse gases that are in our atmosphere. If there are pollutants in the groundwater of the marshes, it will impact all of the plants and animals that live in that specific ecosystem. Excess nutrients such as nitrogen and phosphorus from pesticides and human agricultural activities can lead to eutrophication. When it rains, stormwater carries sediment, nutrients, and chemicals which all end up being deposited in salt marshes. Salt Marshes are located in depositional areas meaning that if there are several pollutants entering into the area they cause a detrimental effect on the biodiversity of the different species living there (New Hampshire Department of Environmental Services, 2004).

 

PAVING OVER PARADISE

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          Throughout the early 1900s, urban runoff polluted a majority of the local bays including the San Francisco bay which is one of the habitats of the salt-marsh harvest mouse. The human population has grown in immense numbers since that and has also impacted the hydrological cycles of wetlands because of the increase in water extraction. Over the past 15 years, the total area of wetlands (swamps, lakes, and marshes) has dropped by 6% (PHYS, 2012). Over the last two decades, human population and construction of cities have caused detrimental effects on the marsh ecosystems.

 

THE ICE IS MELTING

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          If the sea levels keep rising there will eventually be no more salt marshes for the harvest mouse and many other animals to live in. Already, Southern California has lost three-quarters of its salt marshes, and it is projected to be completely gone within the next one hundred years (Xia, 2018). A quote from UCLA professor Glen MacDonald stated that “We are essentially drowning our marshes.”   Polar ice melt is flooding the marshes. In order to help save the little harvest mice we need to take action immediately and face the problem of climate change together. This is a challenging issue to solve, but here are a couple of things we could do:

 

​    -   Reduce the use of greenhouse gases because it contributes to climate change and sea-level rise. 

 

    -    This could be done by driving smart and less, using less hot water, and by reducing, reusing, and recycling (Conserve, 2019).

 

    -    Plant more plants that will absorb the water causing sea level to go down (Clean Ocean Actions).

 

IT'S NOT USED TO THIS PRESSURE

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          The short lifespan of the salt marsh harvest mouse makes it highly vulnerable to becoming extinct. Typically the average lifespan of the species is approximately a year. In their environment, the longest period of time is about 18 months. The low reproduction rates during the mating season also make it challenging for the species to have increased numbers. The average litter is only about four and females usually only mate once a year, spanning from March to October or November, which is considered a low reproduction rate (Environmental Protection Agency, 2010).  Although females are able to reproduce two to three litters per year, only a small number of these mice survive their whole lifespan and make it to adulthood. Predation, habitat destruction of marshes and limited amounts of food such as pickleweed and glasswort, make it hard for the species to survive on top of the small biotic potential the salt-harvest mouse has.