Ecology

1/26/10

Plant and Animal Invaders
by Krista Bergesen

The year 2010 marked the beginning of the UN’s International Year of Biodiversity in response to the present planet’s extinction crisis. But after a while, a person could start to wonder: what are some of the driving forces behind the loss of biodiversity on the planet? Well, there’s fossil fuel burning and deforestation to name a couple. That isn’t the end of the story, however.

Humans may have messed around with the ecological system even more than you may think. The increase in travel and importation going along with a global economy has allowed the transportation of many non-native plants and animals to sensitive habitats.

And that is just the beginning. These invasive species consume the resources of the original flora and fauna in the system. According to the International Union for Conservation of Nature, 40% of species are recorded as extinct because the effects of invasive species.

This has even caused economic damage. Yearly, 1.4 trillion dollars are spent worldwide on control measures and habitat restoration because of the havoc wreaked on the environment. The US itself suffers a loss of 138 billion dollars a year just for its own issues with invasive species.

As already stated, the unattended and unmanaged environment containing invasive species can result in extinction of native species. What’s worse is that the changing global temperatures are enabling non native species to gain a stronger foothold in their new environments.

For example, British Columbian forests are being plagued by mountain pine beetles, whose population has invaded and subsequently increased in number due to the milder winter temperatures. Normally, these creatures would not survive in such a harsh climate, but with the increasing global temperatures they can move further north with increasing speed in destructive numbers. Predictions have estimated that this beetle will be responsible for the devastation of 80% of pine in the province by the year of 2015.

Eradication and control efforts are commonly made against invasive species. However, in areas with multiple introduced species, it can become very difficult to foresee the consequences of various control efforts. Eradicating one invasive species may actually lead to increased damage from another.

The New Zealand ecosystem, only recently populated by humans, has faced many difficulties because of human-introduced species. Their many “management responses” dealing with the threats of invasive plants and animals have often had unforeseen consequences. Livestock, brought by human colonists has limited the habitat of Whitaker’s skink. However, when livestock was removed from certain areas to restore skink populations, predators moved in only to further reduce the skink numbers.

Despite difficulties faced in ecological restorative efforts, they are exceedingly important in maintaining diversity. To be successful, the control projects must be “intensive” and continued for long periods of time, otherwise any progress made with restoration will be lost. Also, when considering a project, all possible outcomes must be considered to ensure that more negative effects on the system are not accidently created.

It should be noted that many successful control efforts in have been documented, and that native species is preservation can be achieved. As global temperatures rise, these efforts will be more and more essential to preserving biodiversity and help slow the accelerating rates of extinction worldwide.

Berger, Matthew. “Invasive Species Threaten US Biodiversity” Guardian Environment Network. <http://www.guardian.co.uk/environment/2010/jan/05/invasive-species-us-waterways>
5 Jan 2010.

Strong, Donald and Robert Pemberton. “Biological Control of Invading Species–Risk and Reform.” Science Magazine. Vol. 288: 1969-1970. 16 Jun 2000.

Norton, David. “Species Invasions and the Limits to Restoration: Learning from the New Zealand Experience.” Science Magazine. Vol. 325: 569-571. 31 Jul 2009.

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1/11/10

In the Middle of a Mass Extinction

by Krista Bergesen

The phrase “mass extinction” can conjure some scary images. Maybe one person imagines a giant meteorite hitting the earth and killing all of the dinosaurs, while another person may think of the last article they read about the human impact on the environment. Either way, it doesn’t sound like a very upbeat topic.

But what is mass extinction anyway? For one, it encompasses much more than what many of us can fathom. It usually means that at least 75% of the species globally have or are dying out on the planet. The planet would never have the same species again, and it would take around 10 million years to regenerate the same species diversity that had once existed.

It may not surprise a lot of people to know that we are in the midst of the largest extinction since that of the dinosaurs. Magazines, television ads, and even movies have tried to spread the word. Some of the messages are depressing, some are inspirational. Either way, the message is clear: the extinction is happening and humans are a major cause.

In a recent study done on the mammals in North America and their extinction rate, a group of scientists concluded that with the migration of humans to the North American continent the “normal” species’ richness declined 15-42%. Going by the definition of a mass extinction said earlier, North American mammals are already one fifth to one half of the way there. And this was before the effects of industrialization.

The anthropogenic time period, or era in which humans have existed is referred to as the “Holocene Period.” When compared with fossil samples from preceding periods, it was concluded that the beginning of the dominance of humans on the North American continent is concurrent with the decline of mammalian diversity. There has been an extinction of nine subspecies and a significant loss of habitat for other North American mammals because of the predominance of humans on the landscape.  Also, the growth of human biomass has matched the decline of the biomass of other species. Thus, the diversity of mammals, as well as the diversity of other animals is being greatly threatened by human development.

Although the study done on North American mammals is by no means representative of the whole world, it does establish one important fact. It quantifies the extinction of a certain type of animal that stands for an important part of the animal population.

In 2006, an estimate was put out by the World Conservation Union stating that 844 species had gone extinct in the past 500 years, attributing the causes to “habitat change, over-exploitation, the introduction of invasive species, nutrient loading, and climate change.” Techniques used for agriculture homogenize the plant life, and often can rid animals of their habitat or food sources. And none of these problems have shown any sign of slowing.

So what can be done? It’s pretty obvious that things have not been going well for other species on the planet with the rapid growth of the human population. For one, awareness, along with conscious action will be very important. Reserves for the natural environment need to be maintained and added to, as well as a development of sustainable energy and food production practices. Sounds difficult, and maybe impossible at this point. But the point is that something needs to be done now or the planet will face a loss of many diverse and important creatures.

Sources:

Reuters. “Humans spur worst extinctions since dinosaurs.” ABC News Online.< http://www.abc.net.au/news/newsitems/200603/s1596740.htm >. 21 March 2006.

Carrasco, Mark, et al. “Quantifying the Extent of North American Mammal Extinction Relative to the Pre-Anthropogenic Baseline”. PloS one. 2009. Volume 4; Issue 12. 8331.

Barnosky, Anthony. “Megafauna biomass tradeoff as a driver of Quaternary and future extinctions.” The National Academy of Sciences of the USA. 2008. Volume 105. 11543-11548.

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12/15/09

The Environmental Impact of Washing Your Car

By: Deidra Metzler

There are various points of view regarding the environmental impact of washing your car as well as various methods to doing so.  That being said, some may question what impact, if any, car washing really has on the environment.  The first thing to be addressed is the bigger picture; wash water drainage.  Where does the wash water really go?  What impact does that wash water have on where it discharges?

All cities have different methods for directing water depending on its source.  For example, New York City, NY discharges ALL water to the sanitary sewer system where water is treated for various constituents (more information on sanitary sewer systems can be found here).  San Diego, CA on the other hand has two drainage systems, one is the sanitary sewer and the other is the storm drain system which discharges water, untreated, to nearby water bodies.  What distinguishes where the water is discharged to?  Location, location, location.  Water from your toilet, sink, bathtub, dishwasher, and washing machine discharges to the sanitary sewer; also known as black and grey water. This is the water that is treated.  The storm drain system drains to local water bodies; for San Diego, CA the water discharged to this system directly affects the Pacific Ocean.  Drainage points are found in streets, parking lots, and landscape in the form of curb inlets, catch basins, etc.

It is important to be familiar with this information to understand the direct impact different methods of car washing can have on the environment.  Knowing that water discharging to the storm drain system is untreated, it is important that car wash water is not discharged to it.  The majority of at home car washing results in discharge into the storm drain system because the wash water is not contained or collected.  Most commercial car washes prevent such discharges by containing wash water and directing it to the sanitary sewer.

What problems do wash water present to the storm drain system?  This also can depend on your location, and the types of pollutants your car may be exposed to.  However, it is most common for cars to have sediment and heavy metals on them.  The source of sediment accumulation is pretty obvious; however, heavy metals may not be an obvious pollutant.  Heavy metals such as copper can come from your brake pads.  Cadmium, lead, and zinc can be sourced from your tires and are considered pollutants to the storm drain system.  Sediment is problematic to aquatic life due to its ability to create a high turbidity, or cloudiness, in the water and the smothering affect it has on fish and amphibian eggs and gills.  Large quantities of heavy metals can be poisonous to all types of wildlife through ingestion or dermal absorption.

Another thing to consider is that infrequent washing of your car can also cause environmental detriment.  If you don’t wash sediment and other pollutants off your car on a regular basis any water discharge from your dirty car would most likely discharge to the storm drain system.  Water discharge from your car can include water from rain, sprinkler water hitting your car, etc.

Car washing can be performed at home without negatively affecting the environment if water is contained and/or redirected to prevent it from reaching the storm drain system.  To prevent water waste, it may be a good idea to collect wash water and distribute it to garden plants.  Or water can be collected and dumped in a drain leading to the sanitary sewer system.

Water can be collected through methods as simple as creating a barrier with sandbags.  Sandbags can be organized to direct water to a different location or to allow water to pool making collection easier.  Anther barrier option would be a large tarp or other similar fabric with a berm, which can be laid down to contain water from washing activities.  Other collection method examples are water vacuums or pumps, however these methods can be difficult without a pooled source of water.  Combining the sandbag or tarp and water pump methods can be extremely effective in reallocating wash water.  There are also products available that do not require the use of water to clean your car.  Such products would eliminate the need to contain wash water.

It is important to note that some commercial car washes are not always effective in containing all wash water.  Lack of complete containment can lead to a discharge to the storm drain system, which in many cases is considered an illegal discharge according to city regulations.  Illegal discharges can cause grounds for a citation and/or a fine by city officials.  Before utilizing a car wash ensure their wash water collection methods are effective in preventing discharges to the storm drain system.

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