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Large Herbivorous Mammals: Exotic Species In Northern Australia By: W.J. Freeland Reviewed By: Joy Bryson & Angela Maresco http://www.smallguide.com.au/maps/australia.gif Purpose The purpose of this article is to examine the effects of man’s deliberate introduction of large, herbivorous ungulates on their non-native environment of Northern Australian savannas. http://www.mareebaheritagecentre.com.au/images/Mt-Mulligan-landscape.jpg Vocabulary Words Co-evolution- when 2 interdependent species adapt to one another Feral- wild; untamed Inter-specific competition- when 2 or more species compete for the same resources Megafauna- large animals Pathogen- agents that cause disease Ungulates- hoofed mammals The Problem • Northern Australian savannas only have 6 large, herbivorous mammal species while Asian and African savannas have more • Environmental changes developed • Man’s arrival to Australia probably is the cause Effects of Europeans Arriving in Northern Australia • Extinction of large, herbivorous marsupials, flightless birds and lizard predators • Possible climate changes • Hunting • Native habitat modification • Due to fire • Large ungulates from Europe, Asia and Africa were introduced Herbivorous Mammals Quiz Directions: Match the scientific name of the following herbivorous mammals with their picture 1. 2. 3. a 4. 5. 6. 7. b 8. 9. c Mus musculus Rattus exulans Orycytolagus cuniculus Sus scrofa Capra hircus Bos banteng Equus asinus Equus caballus i h Bubalus bubalis d e f g Herbivorous Mammals Quiz Answers 1. 2. 3. a 4. 5. 6. 7. b 8. 9. c Mus musculus a Rattus exulans e Orycytolagus cuniculus d Sus scrofa g Capra hircus i Bos banteng h Equus asinus b Equus caballus f Bubalus bubalis c d e i h f g Picture References 1. 2. 3. 4. 5. 6. 7. 8. 9. http://genome.ucsc.edu/images/Mus_musculus.jpg mouse http://www.fieldmuseum.org/philippine_mammals/RODENTIA/Muridae/R ATTUS_exulans2.JPG rat http://fotoohota.spb.ru/members/mikhailov/02.jpg rabbit http://www.retamatour.com/web/02web/fauna/fichas/fotos/mamifer/Susscrofa.jpg Boar http://www.hilozoo.com/images/animals/m_goat.jpg goat http://www.csew.com/cattletag/Cattle%20Website/Images/banteng%20flehm en.jpg ox http://www.roztocze.pl/zoo/img/Osiol1w.jpg ass http://www.ultimateungulate.com/Images/Equus_caballus/E_caballus3.jpg horse http://www.ultimateungulate.com/Images/Equus_caballus/E_caballus3.jpg buffalo New Feral Species • Spread throughout the region • Bos taurus (cow) • equus caballus (horse) • Retained localized distribution • Bos banteng (ox) • Cervus unicolor (deer) • Expanding ranges • Camelus dromedarius (camel) Predicted vs. Actual Densities of Herbivorous Mammals • Based on Damuth relationship QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture. • Two surveys used: • Aerial • CaptureRecapture Table 35.1 The Human Impact Reader “Big is Beautiful But Lonely” • Illustrates concept of the Damuth relationship • Density and body size are inversely related http://www.sciencemag.org/cgi/content/full/289/5484/1487/F1 Explanations for High Population Density 1. Competition 2. Predators 3. Pathogens 4. Plant Defenses ***All have a significant impact on herbivorous mammal population in the natural setting Competition • Influenced by the combination of species in a community (man-made or natural) • Australian man-made community’s deficits compared to Asian/African natural communities • Absence of time for co-evolution=more competition • Absence of large herbivores=impossible to predict • Absence of browsing species=more competition • Influenced by biomass • Biomass was found to be both inversely and directly related to inter-specific competition Predators • Low population of large predators • Lack of predators=higher density of introduced herbivores in Australia • Dingo • Consumed large species of herbivores • Its effects cannot equate with that of species rich natural communities of predators with larger body sizes Quic kTime™ and a TIFF (Unc om pres s ed) dec ompres s or are needed to s ee t his pict ure. http://www.thewildones.org/Gifs/dingo.gif Pathogens • Few native pathogens are capable of infecting the introduced species • Few pathogens accompanied ungulates in Northern Australia compared to native herbivores • Disease causes death in natural population of herbivorous mammals • Less significant in feral herds Plant Defenses • Plants in Australia are similar to plants in other areas • cause no harm to native or introduced species because of coevolution Possible Solution For Population Control • Introduce pathogen • Low cost • Low environmental disturbance • No human involvement • No introduced predators Summary • Humans transported ungulates to Northern Australia and changed the environment • There were undesirable changes in the environmental conditions for the native herbivores due to the deliberate introduction of feral ungulates into Northern Australia • The introduced ungulates did not have natural factors to help control their population • A solution is needed to control the feral ungulate population Related Study “Extinctions of Herbivorous Mammals in the Late Pleistocene of Australia in Relation to their Feeding Ecology: No Evidence for Environmental Change as Cause of Extinction” In this study, scientists tried to determine the cause of extinction of the megafauna species in Northern Australia. This article included information about the survival rate of browsers and grazers and how their body mass was related to their probability of extinction. http://www.ingentaconnect.com/content/bsc/aec/2004/00000029/00 000005/art00007