SPECIES AT RISKLevels of classification:Extinct: A species that no longer existsExtirpated: A species that no longer exists in a specific areaEndangered: A species facing imminent extirpation orextinctionThreatened: A species that is likely to become endangered iffactors reducing its survival are not changedSpecial Concern: A species that may become threatened orendangered because of a combination of factors
SPECIES AT RISKExtinct: A species that no longer existsSPECIES AT RISKGreat auk Passenger pigeon Sea mink
SPECIES AT RISKExtirpated: A species that no longer exists in aspecific areaPaddlefish Atlantic walrus
SPECIES AT RISKEndangered: A species facing imminent extirpationor extinctionBarn owl Swift fox Northern cricket frog
SPECIES AT RISKThreatened: A species that is likely to becomeendangered if factors reducing its survival are notchangedHumpback whale Wood bison
SPECIES AT RISKSpecial Concern: A species that may becomethreatened or endangered because of a combinationof factorsPolar bear Atlantic cod
SPECIES AT RISKWHY?!-Over-hunting (including over-fishing)-Disease-Change of climate and environment (includingpollution)-Habitat loss-Introduction of non-native species
SPECIES AT RISKHabitat lossHuman activity Impacts on ecosystemReplacing naturalvegetation alongcoastlines andwaterfrontsHabitat destruction, shoreline erosion, loss of somespecies, loss of breeding areasDredging to createdeeper water forboatsDisruption of bottom-living organisms and spawningbeds, habitat distructionSediment runofffrom land-clearing,agricultural, andforestry operationsSediments may smother natural habitatsCommercial fishing Bottom trawlers and drag lines injure and kill bottom-dwelling organisms, damage to abiotic features
SPECIES AT RISKIntroduction of non-native speciesNot all non-native species are harmful, but thosethat are would be considered “invasive species”INVASIVE species: Anon-native specieswhose intentional oraccidental introductionnegatively impacts thenatural environment
SPECIES AT RISKINVASIVE species: A non-native species whoseintentional or accidental introduction negativelyimpacts the natural environmentThe brown tree snakewas introduced to thePacific island of Guamas an accidentalintroduction around1950.Caused the extinctionof 9 of Guam’s 12forest birds and halfof the lizard species
SPECIES AT RISKType of Impact ConsequencesEcological -Invasive species compete with or feed on native species,leading to population decline or extinction.-Invasive species change ecosystem dynamics by alteringnutrient cucles or energy flowEconomic -Damage to forests and agricultural crops causes financiallosses-Competition with invasive plants lowers crop yields-Diseases and pests may destroy livestock and crops, killtrees, and harm important species such as honeybeesTourism -Species loss and reduced water quality have negativeimpacts on wildlife viewing, fishing, and water-basedrecreation-Waterways become choked with invasive aquatic plants,rendering them impassable to boatsHealth -Disease-causing organisms, such as West-Nile Virus-Pesticides used to control invasive species cause pollutionand are health risks
SPECIES AT RISKControlling introduced species…Chemical Control (pesticides)Mechanical Control (physical barriers or removal by burning,hunting, trapping, or hand-removal)Biological Control (intentional introduction of organisms tocontrol invasive species)Leaf-eating beetleshelp controlpurple loosetrife
SPECIES AT RISKHow do we know that a species is at risk?Ecologists count the number of animals of a particular species overmany years time and plot population graphs.Population graphs tell scientists if a particular species is in decline.
SPECIES AT RISKPopulation can also indicate predator-prey relationships.
SPECIES AT RISKWhat happens to the moose population when the wolf populationdeclined?The moose population increases when the wolf population decreases.