Invaders
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INVADERS PROGRAM

It may sound like science fiction, but an Arizona-Sonora Desert Museum program is in fact tackling a growing and very real problem - the rise of biological invasions by harmful exotic species of plants and animals. Exotic species - organisms that evolved in one area of the world that now occur in other areas - are becoming increasingly worrisome. One reason behind the worry is that we, humans, are the major intentional and/or unwitting agent of transportation for these marauding plants and animals.

The Desert Museum is one of many public agencies and private organizations working to confront this problem. Its research staff has been identifying the scope and spread of invasives in our region, and its conservation team is mapping the spread of buffelgrass throughout much of the Southwest. The Desert Museum is also facilitating collaborations among local, state and national entities involved in invasive species monitoring and management.

The Invaders Program was initiated in 2005 to tackle the rise of biological invasions by harmful exotic species of plants and animals, with an emphasis on seven species of interest. Since then, the program has expanded to include a broad number of invasive species within the Sonoran Desert, hands-on research, and education to community members. Our goals are to identify the impacts of invasives in our region, map the spread of these invasives, collaborate with eradication projects, and educate others about the resulting implications to the Sonoran Desert. Together, we are making a difference!

Who We Are and What We Do

We are a dedicated group of Desert Museum staff and volunteers that want to contribute to early detection of invasive species in the Sonoran Desert Region. We work closely with community partners throughout the region to map, conduct field experiments and research, collaborate with partners in control efforts, and provide educational materials and presentations to community groups on invasive species.

What is an invasive species?

An invasive species is non-native to the ecosystem in consideration and causes or is likely to cause economic or environmental harm or harm to human health.

Sometimes you will see invasive species referred to as exotic, alien, or non-indigenous species. The problem with these names is that they only refer to the non-native part of the definition above. Many exotic or alien species do not cause harm to our economy, our environment, or our health. In fact, the vast majority of "introduced" species do not survive and only about 15% of those that do go on to become "invasive" or harmful.

An invasive species grows/reproduces and spreads rapidly, establishes over large areas, and persists. Species that become invasive succeed due to favorable environmental conditions and lack of natural predators, competitors and diseases that normally regulate their populations.

What is an introduction?

When a species ends up in a new ecosystem, it is considered "introduced." Species do naturally change their ranges slowly over time, but it is not these "natural" events that we are concerned with. Most of the introductions that result in invasive species are human caused.

In some cases, we deliberately introduce species. Examples of this include garden ornamentals, range forage plants for cattle, animals and insects used to control other organisms (particularly in agriculture), and plants used for erosion control and habitat enhancement for wildlife.

Other species are introduced accidentally on imported nursery stock, fruits, and vegetables, in ship ballast waters, on vehicles, in packing materials and shipping containers, through human-built canals, and from human travel.

Why do we care?

Invasive species are a form of biological pollution. Invasive species decrease biodiversity by threatening the survival of native plants and animals. They interfere with ecosystem function by changing important processes like fire, nutrient flow, and flooding. Invasive species hybridize with native species resulting in negative genetic impacts.

They spread easily in today's modern global network of commerce and are difficult and costly to control. Invasives impede industries and threaten agriculture and can endanger human health. Invasive species are a significant threat to almost half of the native US species currently listed as federally endangered.

The costs to prevent, monitor and control invasive species are enormous not to mention the costs to crop damage, fisheries, forests, and other resources. Invasives cost the US $13 billion annually. Some of the most invasive and harmful species cost in excess of $100 million each annually.

Do not be a vehicle of dispersion

Most invasive species are introduced by humans accidentally. Learn how to prevent carrying invasive species on your boats, cars, bicycles, motorcycles, and socks and hiking boots.

Adopt a Conservation Mentality - www.habitattitude.net

What you can do to prevent species dispersion

Garden wisely

Avoid plants that self seed and show up outside of your garden. Do not use weedy volunteers from parks and abandoned lots. Most non-native species are okay; the invasive species are the ones to avoid. Planting a native species garden can be very rewarding. There are many resources to ehlp with creating low-maintenance and colorful native plant gardens that attract birds and wildlife.

Check out the National Wildlife Federation Native Gardening and Invasive Plants Guide.

Educate others

Tell your friends and family what you have learned and let your local nursery grower know your concerns if they are selling invasive species.