Invasion of the Black Rat Rattus rattus Alexis Roque Karin Lisa Sirjoo

Introduction  Species: Rattus rattus  Also Know as Ship Rat and Roof Rat  Originated in Asia  Found primarily around human habitations  Mainly vegetarian diet uments/presentation/jcudev_008406~2.3.jpg

Physical Description  Medium sized body  Large ears  Tail usually longer than body  Weighs between 70 to 300 grams  Usually black  Can be any combination of black, white or grey  Males longer and heavier than females

Lifestyle  Black Rats are nocturnal and omnivorous  Breed and reproduce throughout the year  Live together in large groups

Geographic Distribution  Found on all continents especially tropical regions  Most common in coastal areas  Agile climber – often lives in high places like top floors of buildings or in trees  Rarely swims  Spreads disease

Black Rat Vs. Santiago Rice Rat  The Black Rat negatively affects the population of the Rice Rats  Interference of population by aggression  Removal of R. rattus slowed population decline of N. swarthi

Black Rat Vs. Santiago Rice Rat  Interference Competition  Both species share the same interest in food sources  General encounters cause confrontation between species  Climate factors affect the population growth of the Black Rat

Black Rat Vs. Deer Mice  Deer mice is native to the California Channel Islands  Black Rat affects Deer Mice in 2 ways:  1. Increasing Predation & Competition  2. Introducing new parasites & diseases  Parasite: Whipworm - Trichuris muris  Habitat and foraging behavior overlap

Black Rat Vs. Deer Mice  Whipworm is transferred through contaminated materials and foods  Eggs of the worm are infectious within 3 weeks of being passed from the system Deer%20mouse.jpg

Black Rat Vs. Sea Birds  Black rat is largest contributor to seabird extinction  Prey mostly on on small burrow nesters  Smaller birds are more vulnerable

Invading the Canary Islands  Seven main islands  100km from NW coast of Africa  Varied vegetation  3672 terrestrial endemic species  Of those, 1434 introduced by man www-biology.ucsd.edu/news/images/ L

Invading the Canary Islands Ecological Effects of Rattus Rattus  One of the world’s100 worst invasive species (IUCN, 2001)  Present on all 7 islands  Arrived with European conquistadors in the 15 th century

Invading the Canary Islands Ecological Effects of Rattus Rattus  Affects plant regeneration and structure  Predator of birds, especially eggs and chicks  Causes decreased breeding success in birds history/conservation-002.jpg

Human Prevention  Sanitation  Traps & Poison baits  Sound & Electronic devices  Control by cats & dogs  Eradication

References  Harris, Donna B., Gregory, S.H., Macdonald, D.W Space invaders? A search for patterns underlying the coexistence of alien black rats and Galápagos rice rats. Oecologia 149:  Harris, Donna B., Macdonald, D.W Interference competition between introduced black rats and endemic Galapagos rice rats. Ecology 88:2330.  Jones Severity of the Effects of Invasive Rats on Seabirds: A Global Review. Conservation Biology 22:  Nogales, M., Rodriguez, J.L., Marrero, P Ecological effects and distribution of invasive non-native mammals on the Canary Islands. Mammal Society 36:  Smith, Katherine F., Carpenter, S.M Potential spread of introduced black rat (Rattus rattus) parasites to endemic deer mice (Peromyscus maniculatus) on the California Channel Islands. Diversity distributions 12:742.

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