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Working for Biodiversity andProtection from Invasive Species

Did you know?If you raise tomatoes in yourgarden, chances are you tillthe soil, periodically addlime, nutrients, and water,and you attempt to control“pests” such as weeds,insects, and woodchucks. Ittakes a lot of effort to raise anice crop of tomatoes in aspecially designated place onyour property, and manypeople have done so formany years. Have you start-ed to find over the years thattomato plants are growingin the woods, on the side ofroad, or in other farmfields—growing freely with-out any assistance or man-agement? No, of course not,because tomatoes, while anintroduced species, are notinvasive.

Oriental Bittersweet,however, is an invasivespecies that may come toyour front door as a decora-tive, seasonal wreath.Through seed and berry dis-persal, this plant can easilyestablish and grow in youryard and woodland area.

It can take anywhere from8 years to 388 years (aver-age 147 years) for non-native or introducedspecies to “become” inva-sive. Ecologists often referto the issue of invasivespecies as “an explosion inslow motion.”

What are invasive species?

Invasive species are organisms that havebeen introduced into an area wherethey did not originate or evolve, andthat usually have no natural enemies

(Westbrooks, 1998). According to theFederal Executive Order on InvasiveSpecies, “invasive species means an alienspecies whose introduction does or is like-ly to cause economic or environmentalharm or harm to human health.”

Invasive species are non-native –sometimes referred to as “exotic” or“alien” species--that have been intro-duced by humans either on purpose oraccidentally (as a result of our methods ofshipping and transportation, etc.). Thesespecies can “get a hold” and out-competenative species. Not all non-native speciesare invasive, in fact, it is estimated thatonly 1% of all introduced species becomeinvasive. The vast majority of introducedspecies cannot thrive without the aid ofcultivation or human management.

What are some other commonlyused terms?

Naturalized species are non-nativespecies considered to be well establishedand growing without human aid, eventhough they originated in another area.Most naturalized species are not inva-sive. Some examples of naturalizedspecies include Asiatic Dayflower,Mouse-eared Chickweed, Deptford Pink,Ring-necked Pheasant, and House Finch.

Native species are species that natu-rally evolved within a region or ecosys-tem and are better adapted, more appro-priate and ecologically suited to thatarea. Most native species have natural“enemies” and are balanced throughecosystem conditions and competition.And yes, there are some native speciessuch as poison ivy and green brier thatare considered “aggressive” or “pests”by human standards. However, they donot alter the surrounding ecosystemhabitat and processes, and they also pro-vide food and cover for local wildlife.

What are the characteristics thatmake a species invasive?

➣Rapid growers.➣Mature quickly (have short juvenile

periods).➣The timing of their life cycle is different

from native species. In the case of manyinvasive plants, they break dormancyearlier in the season or keep growinglater in the season, as well as flower,fruit, and disperse seed at differenttimes giving them an “unfair” advan-tage for soil nutrients, sunlight, etc.

➣Produce many fruits, seeds, or off-spring. In the case of many invasiveplants, seeds can remain dormant andviable in the soil for many years.

➣Disperse and spread fruits, seeds,spores, etc. easily through wind,stormwater runoff, and by birds thatfeed on the fruits and seeds.

➣“Crowd out” other species. In the caseof plants they may have dense foliagethat shades out other species anddense, shallow root systems that donot allow any “extra room.”

➣Some plant species are allelopathic,producing chemicals that inhibit thegrowth of other plants.

➣Able to thrive in a broad range ofenvironmental conditions includingdisturbed and/or polluted sites.

➣Lack natural enemies or other “checks& balances.”

What are some specific examplesof how non-native, invasivespecies have been or continue tobe introduced?

➣Through the trading and importing ofplants and seeds that have been usedfor agricultural crop production andornamental landscaping. A few of themany landscape plants includeOriental Bittersweet, JapaneseHoneysuckle, and Multiflora Rose.Other organisms, such as insects andplant diseases, can be contained with-in these “foreign” plants and is the

T o d a y ’ s F o r e s t • T o m o r r o w ’ s L e g a c yT o d a y ’ s F o r e s t • T o m o r r o w ’ s L e g a c y

Invasive specieshave become sucha great concernthat on Feb. 3, 1999,PresidentClinton signedExecutive Order13112, whichdirects the agencies of theexecutive branchof the federalgovernment towork to preventand control theintroduction and spread ofinvasive species.

Where do I turn for more information and help?

The RI Natural History Survey(401) 874-5800 • www.uri.edu/ce/rinhs• Information about invasive species, Rhode

Island’s ecology, biodiversity protection,and extensive links to many related organi-zations and publications.

The Rhode Island Wild Plant Society(401) 783-5895 • www.riwps.org• List of native plants; official RI Invasive

Species Council list of invasive plants; spe-cial programs, affiliations & newsletter.

URI CE GreenShare Program (401) 874-2900www.uri.edu/ce/ceec/greenshare.html• Sustainable Trees & Shrubs manual – lists

over 250 disease and insect-resistant plantsthat thrive in Southern New England withminimal maintenance, available on-linewww.uri.edu/ce/factsheets/sheets/sustplant.html

Other Recommended On-Line Resources

Federal efforts concerning invasive speciesand the National Invasive Species Council:www.invasivespecies.gov.

The Nature Conservancy’s site, includinginformation on invasive species manage-ment: http://tncweeds.ucdavis.edu.

URI Home*A*Syst Program, photos of someof Rhode Island’s invasive species:www.uri.edu/ce/wq/has/html/exotics.html

Connecticut Invasive Plant Working Groupincludes recommendations for control andmanagement of invasive plants:www.eeb.uconn.edu/cipwg

Other RecommendedPublications

Marinelli, J. (ed.) 1996. Invasive Plants: Weedsof the Global Garden. Brooklyn, NY: BrooklynBotanic Garden Handbook #149.

Shonbrun, S.B. (ed.). 1998. “Invaders.”Conservation Notes of the New England WildFlower Society, Vol. 2(3).

Westbrooks, R. 1998. Invasive Plants: Changingthe Landscape of American: Fact Book.Washington D.C.: Federal InteragencyCommittee for the Management of Noxiousand Exotic Weeds.

The journal of the Natural Areas Association(www.matareas.org) publishes many articlesabout the ecology and control of invasivespecies.

The information used to compile this factsheetwas provided by Lisa Gould, Executive Director,Rhode Island Natural History Survey.

Programs and activities are available to all persons withoutregard to race, color, sex, disability, religion, age, sexual orienta-tion, or national origin.

This project is a collaboration of the Southern New EnglandForest Consortium, Inc.1, and the University of Rhode IslandCooperative Extension Home*A*Syst Program2. Written byHolly K. Burdett 2, Christopher Modisette1, Alyson McCann2 andBrianne Neptin2. Special thanks to all publication reviewers.Funding for this project was provided by the USDA ForestService in cooperation with the Rhode Island Department ofEnvironmental Management Division of Forest Environmentand the USDA Renewable Resources Extension Act, URICooperative Extension.

T o d a y ’ s F o r e s t • T o m o r r o w ’ s L e g a c yT o d a y ’ s F o r e s t • T o m o r r o w ’ s L e g a c y

method by which Dutch Elm Diseaseand the Chestnut Blight were broughtto the US.

➣Through our methods of transporta-tion. Everything from the ballastwater of ships, sheep wool, packingcrates, and car tires can travel manymiles over a relatively short time andprovide a perfect means for “hitchhik-ers.” The large red seaweedGrateloupia doryphora, and Asian ShoreCrab, which now grow throughoutNarragansett Bay were “introduced”via ballast water.

➣Through the release or escape of exot-ic pets or aquarium plants. Fanwort isan example of an aquarium plant thathas become invasive in RI.

➣Through construction and the movingof soil and other “fill.” The soil fromone area can potentially contain andintroduce seeds and organisms toanother area. Furthermore, commonforms of erosion and sediment controlson construction sites include stakedhay bales, which are often importedfrom Canada. It is believed thatNodding Thistle came to RI this way.

Why, exactly, are invasive speciessuch a big concern?

Loss of biodiversity and basic ecologicalprocessesThe ecosystems of the world consist ofmillions of animals, plants, protists, fungi,bacteria, and viruses that interact withthe physical environment. Each ecosys-tem has its own combination of organ-isms. Non-native invasive species usuallyalter the natural succession or function ofan ecosystem over the long term. Thishappens because native species are out-competed or overtaken by an invasivespecies, which often leads to one or morenative species becoming extinct in thatecosystem. All of the other organisms inthe ecosystem that depended on or co-existed with the now-extinct naturalspecies are now adversely impacted.These impacted species (often 12 differentspecies per one species in temperate cli-mates, as many as 30 species in the tropi-cal rainforests) must either change toadapt or also become extinct.

Such a loss of biodiversity and basicecological processes can affect our agri-cultural food production, water qualityprotection, and health care worldwide.

Grave economic impacts and expenseInvasive species cost the United Statesan estimated $123 billion annually indirect economic losses each year, affect-ing food crops, golf courses, the growingof turf and ornamentals, industrial sites,forestry, aquatic sites, recreational areas,municipal water supplies—the list is on-going and extensive. This figure doesnot include damage to native speciesand ecosystems. Worldwide, the costsare even higher.

What are some common, widespread invasive species in Rhode Island?

Some animal species include theNorway Rat, Rock Dove, HouseSparrow, European Starling, Mute Swan,Monk Parakeet, Japanese Shore Crab,and Green Crab.

Some plant species include PurpleLoosestrife, Multiflora Rose, AutumnOlive, Glossy Buckthorn, JapaneseHoneysuckle, Asiatic Bittersweet, andmany others.

Some plant species that are agreed tobe invasive in Rhode Island, but moreinformation about the invasiveness of theircultivars is still needed include NorwayMaple, Japanese Barberry, Burning Bush,and Morrow and Bella Honeysuckle.

Some potentially invasive plantspecies include Water Hyacinth,Eurasian Water-milfoil, Water-chestnut,and Mile-a-minute Weed (known fromone site in the state).Assessed by the Rhode Island InvasiveSpecies Council during 2001

What can I do to make a difference?Invasive species are a serious problemthat is not going to disappear—many ofthem are here to stay. Attempts at con-trolling or eradicating the problem can bea daunting prospect, both financially anddue to the intensity of labor required. Butthere are some things that each of us cando at the individual level, the biggestbeing to prevent further introduction ofnon-native species.

Use the Record of Woodland Area Plansand Activities sheet to record actions youplan to take and develop a time frame foraccomplishing activities. Refer to the listof contacts and resources listed at theend of this factsheet for specific informa-tion and assistance with these activities.

➣When landscaping or enhancingwildlife habitat in your backyard andwoodlands, use native species. Learnwhich plant species are consideredinvasive to Rhode Island and the NewEngland region and avoid plantingthem. Consult with the URICooperative Extension GreenshareSustainable Trees and Shrubs Manual orrefer to factsheet Working for WildlifeHabitat for a list of suggested trees,shrubs and other plants.

➣Learn to identify the non-native andinvasive species that may already existin your backyard and woodlands andthe possible control methods andoptions available. Avoid waiting untilthe problem appears “seriousenough.” Be vigilant and monitor theproblem regularly. See the RhodeIsland Invasive Species Council list ofinvasive plants at www.riwps.org.

➣Minimize land disturbances and soilexposure on your property. These

areas are often prime targets for non-native invasive plant species to movein and take over.

➣When traveling—especially in foreigncountries, do not bring plants, seeds,or fruit back home with you.

➣Be very careful with “exotic” pets. Takeextra measures to learn your pet’sbehavior and how to prevent or antici-pate accidental escapes. In the eventthat you no longer wish to have thispet, please take it and any artificialhabitat features (such as an aquarium)to a proper pet store or other appropri-ate facility for assistance with place-ment. Never let an exotic pet “go free.”

About 60% ofinvasive specieshave resultedfrom horticulture,another 25%resulted fromagency and otherprofessional“recommendations”for soil and water conservation, and the remaining15% were accidental.

The mission ofthe Rhode IslandInvasive SpeciesCouncil, formedin 1999, is toprotect nativebiodiversity inRhode Island.This Council willgather and conveyinformation onthe presence, distribution, ecological andeconomic impacts,and managementof invasivespecies; promoteuses of nativespecies and non-invasivealternativesthroughoutRhode Island;and work cooperativelywith researchers,conservationorganizations,government agencies, thegreen industries,and the generalpublic to identifyand manage inva-sive species pro-actively andeffectively. TheCouncil uses atotal of 13 criteria to determine if aspecies isWidespread and Invasive,Restricted andInvasive, orPotentiallyInvasive.

Rock Dove

WaterChestnut

NorwayMaple

PurpleLoosestrife