DOCSLIB.ORG

Invasive Aquatic Plants and the Aquarium and Ornamental Pond Industries Shakira Stephanie Elaine Azan

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Invasive Aquatic Plants and the Aquarium and Ornamental Pond Industries Shakira Stephanie Elaine Azan Ryerson University Digital Commons @ Ryerson Theses and dissertations 1-1-2011 Invasive aquatic plants and the aquarium and ornamental pond industries Shakira Stephanie Elaine Azan Follow this and additional works at: http://digitalcommons.ryerson.ca/dissertations Part of the Plant Sciences Commons Recommended Citation Azan, Shakira Stephanie Elaine, "Invasive aquatic plants and the aquarium and ornamental pond industries" (2011). Theses and dissertations. Paper 818. This Thesis is brought to you for free and open access by Digital Commons @ Ryerson. It has been accepted for inclusion in Theses and dissertations by an authorized administrator of Digital Commons @ Ryerson. For more information, please contact [email protected]. INVASIVE AQUATIC PLANTS AND THE AQUARIUM AND ORNAMENTAL POND INDUSTRIES by Shakira Stephanie Elaine Azan Master of Philosophy, University of the West Indies, Mona Campus, Jamaica, 2002 Bachelor of Science (Hons.), University of the West Indies, Mona Campus, Jamaica, 1997 A thesis presented to Ryerson University in partial fulfilment of the requirements for the degree of Master of Applied Science in the Program of Environmental Applied Science and Management Toronto, Ontario, Canada, 2011 ©Shakira Azan 2011 AUTHOR’S DECLARATION I hereby declare that I am the sole author of this thesis. I authorize Ryerson University to lend this thesis to other institutions or individuals for the purpose of scholarly research. ........................................................................................ I further authorize Ryerson University to reproduce this thesis by photocopying or by other means, in total or in part, at the request of other institutions or individuals for the purpose of scholarly research. ......................................................................................... ii ABSTRACT INVASIVE AQUATIC PLANTS AND THE AQUARIUM AND ORNAMENTAL POND INDUSTRIES Master of Applied Science 2011 Shakira Stephanie Elaine Azan Environmental Applied Science and Management Ryerson University The purpose of the research was to clarify the common traits of a successful aquatic invasive plant. The biological traits of aquatic plants sold by aquarium and ornamental pond stores in the Greater Toronto Area, Ontario were analysed using logistic regression analyses (LRM). The multinomial LRM successfully predicts group identity 63% of the time, clearly differentiating native invasive and native non invasive from alien invasive (AI), but not alien non invasive (ANI) from AI. In contrast, the binomial LRM effectively discriminates ANI from AI taxa 77% of the time. The variables that best discriminated between AI and ANI are type of propagation strategies, number of propagation strategies used, number of dispersal mechanisms used, minimum temperature, and sales volume of aquatic plants as a proxy for introduction. Recognizing the common traits of successful invaders allows for the identification of ANI taxa that have the potential to become invaders, prior to introduction, thus preventing future invasions. iii ACKNOWLEDGEMENTS “A gem cannot be polished without friction, nor a man perfected without trials” Chinese proverb When I decided to embark on the journey of pursuing another Masters, I had no expectations, but had an open mind for anything that could happen. I did not foresee that this journey would have been filled with so many unforgettable experiences that have helped to shape me into the gem that I have become. To all who contributed to these experiences, I would like to say a big thank you. The completion of this thesis would not have been possible without the assistance of a number of persons; to them I would like to express my deepest appreciation. To my heavenly Father, I would like to thank you for life and for creating me with a questioning mind. I also express my gratitude for allowing me to make it to the end and to fulfil the requirements of the programme. To my supervisors, Drs. Michal Bardecki and Andrew Laursen, I extend my appreciation for your advice and dedication in reviewing and providing constructive critiques on this paper. For your continuous support, guidance and encouragement, even when my insecurities were showing, thank you. To my family and friends who stood by me and never allowed me to give up, always encouraging and praying for me, I could never have done it without your love and affections. iv TABLE OF CONTENTS AUTHOR’S DECLARATION .................................................................................................................................... ii ABSTRACT .................................................................................................................................................................. iii ACKNOWLEDGEMENTS ........................................................................................................................................ iv TABLE OF CONTENTS ............................................................................................................................................ v LIST OF TABLES .................................................................................................................................................... viii LIST OF FIGURES ..................................................................................................................................................... ix LIST OF APPENDICES ............................................................................................................................................. x LIST OF ABBREVIATIONS .................................................................................................................................... xi 1.0 INTRODUCTION ........................................................................................................................................... 1 1.1 Invasive alien species ............................................................................................................................. 1 1.1.1 The Problems with prevention, control and mitigation of IAS ...................................... 3 1.2 Aquatic plant species ............................................................................................................................. 4 1.2.1 Aquatic plants and the aquarium and ornamental pond industries .......................... 7 1.3 Rationale for study ................................................................................................................................. 9 1.4 Purpose and objectives ....................................................................................................................... 10 2.0 LITERATURE REVIEW ........................................................................................................................... 13 2.1 General Introduction .......................................................................................................................... 13 2.2 Pathways of introduction for aquatic plants ............................................................................. 15 2.2.1 Aquarium industry ...................................................................................................................... 16 2.2.2 Internet, mail parcels/order catalogues ............................................................................ 25 2.2.3 Ornamental ponds ....................................................................................................................... 27 2.3 Invasion success of aquatic plants ................................................................................................. 28 2.3.1 Plant invasions .............................................................................................................................. 28 2.3.2 Traits of successful aquatic plant invaders ....................................................................... 34 2.3.2.1 Reproduction and perennation ........................................................................................ 35 2.3.2.2 Life form and growth characteristics ............................................................................ 40 2.3.2.3 Morphological plasticity ...................................................................................................... 42 2.3.2.4 Boom‐and‐bust and propagule pressure ..................................................................... 43 2.4 Legislative framework for the introduction of aquatic plants into Ontario ................. 46 v 2.4.1 Canadian Food Inspection Agency ........................................................................................ 46 2.4.1.1 CFIA and invasive plants ..................................................................................................... 47 2.4.1.2 Administration and enforcement of the CFIA ............................................................ 52 2.5 Risk assessment ..................................................................................................................................... 56 2.5.1 CFIA and risk assessment .......................................................................................................... 57 2.6 Link between literature review and methodology .................................................................. 60 3.0 METHODOLOGY ........................................................................................................................................ 62 3.1 Selection of potential aquatic
Load more

Recommended publications
  • Alternanthera Reineckii ''Roseafolia'' No. 023 Alternanthera Reineckii
    Ceratophyllum demersum is a Family Ceratophyllaceae genuine cosmopolitan found all Continent Cosmopolitan over the globe. It has no true roots Region Cosmopolitan but can be planted in the bottom. Country of origin In the wild it is often found rooted, Height 5-80+ cm with the lower leaves forming Width 5-15+ cm anchors. As a floating plant it Light requirements very low-very high provides a good hiding-place for Temperature 10-28 °C 1 young fish. C. demersum can be Hardness tolerance soft-very hard useful in combating algae pH tolerance 6-9 because it consumes nutrients in Growth fast the water and secretes substances Demands easy that counteract algae. Some varieties are difficult to transport. Ceratophyllum demersum No. 021 #023 The purple colour Family Amaranthaceae underneath Alternanthera reineckii Continent South America ''roseafolia'' leaves provides an Region South America effective contrast to the many Country of origin green plants in an aquarium - Height 25-50 cm particularly when planted in Width 10-15 cm groups. Good light encourages the Light requirements medium-very high leaves to turn red. Most Temperature 17-28 °C 2 Alternanthera species are difficult Hardness tolerance soft-hard to grow, but this one is relatively pH tolerance 5-8 undemanding. Easy to propagate Growth medium by nipping off the terminal bud Demands medium and planting it in the bottom. This Common Name: Red Temple also makes the mother plant more Alternanthera reineckii bushy, because more side shoots ''roseafolia'' No. 023 are formed. #023B Alternanthera reineckii Family Amaranthaceae ''lilacina'' needs plenty of light to Continent South America grow and form dark-red leaves.
    [Show full text]
  • EVENT! NEWSLETTER EXCHANGE KWAS to The
    The Official Newsletter of the Ottawa Valley Aquarium Society Currents BIOLOGICAL APPROACHto AQUASCAPING EARTH DAY EVENT! NEWSLETTER EXCHANGE KWAS to the RESCUE! ...and MORE! Pictures CLUB of the year! NEWS JAN-FEB 2012 “Patrick S” OVAS FORUM PICTURE OF THE YEAR IT’S A 3-WAY TIE! “jojo621” “Chubs” 2 Ottawa Valley Aquarium Society • OVAS.CA “Patrick S” THE FIRST SPLASH appy New Year to all OVASians! I wish you all Ha very successful and fun-filled year in your aquaristic endeavours! For those of you thinking of becoming an OVAS club member, January is good time to join. Membership prices are discounted as we approach the half-way mark of the 2011-12 season. There are still many events to enjoy: our monthly meetings, the annual Giant Auction, our first ever Earth Day Event, and the end-of-year pig roast. We look forward to seeing newcomers take part in our live community of aquarium and pond enthusiasts! The first issue of the year hasn’t quite turned out as I had planned. My work and home schedule have been pretty hectic these past weeks, so I wasn’t able to finish two of our regular columns: “Meet the OVASians” and “Getting to know... (one of our sponsors)”. My apologies – I will make up for it in March! However, we have a great contribution from Joe Schwartz, our club’s Vice President. He has provided us with a well documented and informative article entitled “Biological Approach to Aquascaping”. The picture that graces the cover is of Joe’s 180 gallon planted tank.
    [Show full text]
  • Invasive Alien Plants an Ecological Appraisal for the Indian Subcontinent
    Invasive Alien Plants An Ecological Appraisal for the Indian Subcontinent EDITED BY I.R. BHATT, J.S. SINGH, S.P. SINGH, R.S. TRIPATHI AND R.K. KOHL! 019eas Invasive Alien Plants An Ecological Appraisal for the Indian Subcontinent FSC ...wesc.org MIX Paper from responsible sources `FSC C013604 CABI INVASIVE SPECIES SERIES Invasive species are plants, animals or microorganisms not native to an ecosystem, whose introduction has threatened biodiversity, food security, health or economic development. Many ecosystems are affected by invasive species and they pose one of the biggest threats to biodiversity worldwide. Globalization through increased trade, transport, travel and tour- ism will inevitably increase the intentional or accidental introduction of organisms to new environments, and it is widely predicted that climate change will further increase the threat posed by invasive species. To help control and mitigate the effects of invasive species, scien- tists need access to information that not only provides an overview of and background to the field, but also keeps them up to date with the latest research findings. This series addresses all topics relating to invasive species, including biosecurity surveil- lance, mapping and modelling, economics of invasive species and species interactions in plant invasions. Aimed at researchers, upper-level students and policy makers, titles in the series provide international coverage of topics related to invasive species, including both a synthesis of facts and discussions of future research perspectives and possible solutions. Titles Available 1.Invasive Alien Plants : An Ecological Appraisal for the Indian Subcontinent Edited by J.R. Bhatt, J.S. Singh, R.S. Tripathi, S.P.
    [Show full text]
  • FOTAS Fish Tales 05.4
    In this issue: 3 The Future of the Fed- eration of Texas Aquarium Societies Greg Steeves 8 FOTAS BAP 17 FOTAS HAP 24 FOTAS CARES Greg Steeves 25 Spawning the Buffalo- Volume 5 Issue 4 head Cichlid The FOTAS Fish Tales is a quarterly publication of the Federation of Texas Duc Nguyen Aquarium Societies a non-profit organization. The views and opinions contained within are not necessarily those of the editors and/or the officers 27 GloFish, Love them or and members of the Federation of Texas Aquarium Societies. Hate them, They are here to stay! FOTAS Fish Tales Editor: Gerald Griffin [email protected] Gerald Griffin Fish Tales Submission Guidelines 31 What the Heck is an ESU? Articles: Leslie Dick Please submit all articles in electronic form. We can accept most popular software formats and fonts. Email to [email protected]. Photos and 35 Spawning Julido- graphics are encouraged with your articles! Please remember to include the photo/graphic credits. Graphics and photo files may be submitted in chromis dickfieldi any format, however uncompressed TIFF, JPEG or vector format is pre- Gerald Griffin ferred, at the highest resolution/file size possible. If you need help with graphics files or your file is too large to email, please contact me for alterna- 37 Meet the San Antonio tive submission info. Aquatic Plant Club Art Submission: Chris Lewis Graphics and photo files may be submitted in any format. However, uncom- pressed TIFF, JPEG or vector formats are preferred. Please submit the 39 Participating in the FO- highest resolution possible. TAS BAP and HAP Next deadline…… Gerald Griffin January 15th 2016 On the Cover: COPYRIGHT NOTICE GloFish - Photos by York- All Rights Reserved.
    [Show full text]
  • Growers Award Program (GAP)
    GGRROOWWEERRSS AAWWAARRDD PPRROOGGRRAAMM ((GGAAPP)) V.6 1 Welcome to the North Jersey Aquarium Society's Growers Award Program (GAP). The purpose of the GAP is to: 1. encourage members to integrate aquatic plants into their filtration and aquascaping 2. recognize the talents and achievements of our members 3. provide a better selection of plants at our auctions Two programs are available to award members, including those who only keep a few types of plants in their aquariums. Any NJAS member in good standing can participate in the programs. The Achievement Program In the Achievement Program, points are awarded for each species propagated, one time only. This is normally done by submitting the propagations for auction. 15 and 20 point plants require a short, written “grower report” of one or more paragraphs to be credited. Members can earn an additional 2.5 points for articles written about aquarium plants submitted to the society’s newsletter, 2.5 points for participating in a panel on plants, and 5 points for presenting a program. Member standings are published on the NJAS website as well as in our newsletter. Plaques are awarded to the member with every new level of achievement. It is the grower's responsibility to see that points have been properly recorded. Suggestions are welcomed. Decisions by the GAP Chair are final. Achievement Level Points Required Other Requirements I Grower 75 propagations in at least 2 categories II Advanced Grower 150 propagations in at least 4 categories to date III Senior Grower 300 propagations in at least
    [Show full text]
  • Low Risk Aquarium and Pond Plants
    Plant Identification Guide Low-risk aquarium and pond plants Planting these in your pond or aquarium is environmentally-friendly. Glossostigma elatinoides, image © Sonia Frimmel. One of the biggest threats to New Zealand’s waterbodies is the establishment and proliferation of weeds. The majority of New Zealand’s current aquatic weeds started out as aquarium and pond plants. To reduce the occurrence of new weeds becoming established in waterbodies this guide has been prepared to encourage the use of aquarium and pond plants that pose minimal risk to waterbodies. Guide prepared by Dr John Clayton, Paula Reeves, Paul Champion and Tracey Edwards, National Centre of Aquatic Biodiversity and Biosecurity, NIWA with funding from the Department of Conservation. The guides will be updated on a regular basis and will be available on the NIWA website: www.niwa.co.nz/ncabb/tools. Key to plant life-forms Sprawling marginal plants. Grow across the ground and out over water. Pond plants Short turf-like plants. Grow in shallow water on the edges of ponds and foreground of aquariums. Includes very small plants (up to 2-3 cm in height). Most species can grow both submerged (usually more erect) and emergent. Pond and aquarium plants Tall emergent plants. Can grow in water depths up to 2 m deep depending on the species. Usually tall reed-like plants but sometimes with broad leaves. Ideal for deeper ponds. Pond plants Free floating plants. These plants grow on the water surface and are not anchored to banks or bottom substrates. Pond and aquarium plants Floating-leaved plants. Water lily-type plants.
    [Show full text]
  • SOME OBSERVATIONS on the IMPORTANCE of Aponogeton Rigidifolius in ENDEMIC FISH BREEDING HABITATS Iitloya
    Kfflhories and Aquatic Resources, 2004 SO M E OBSERVATIONS ON THE IMPORTANCE OF Aponogeton rigidifolius IN ENDEMIC FISH BREEDING HABITATS A.S.L.E. Corea,jM.S.S. Jayasekara and N.N.E Cooray Notional Aquatic Resources Research and Development agency (NARA), Crow Island, Mattakkuliya, Colombo 15, Sri Lanka Aponogeton rigidifolius is an endemic aquatic plant with thin long laiives extending to over 0.5m in length. This species is mainly found in ilroams in the wet zone. Fish species associated with A.' rigidifolius were sampled using a drag net made of mosquito netting material. The net was dragged 10 times And the mean number of fish caught per net was recorded. In areas with a dShse population of A. rigidifolius (82 ± 6.33 plants / m2) with leaf size 46 ± 10.2 cm, the number of R. vaterifloris collected per net sample was 32 ± 5.6. The size range of fish collected was 0.8 - 3.0 cm. In the areas with dense patches of A. rigidifolius, the dominant species was R. vaterifloris. The number of R. vaterifloris caught per net sample in areas where there were no A. rigidifolius was <10, and the size range of fish in these areas was 1.4 * 2,8 cm. The fry which were <1.2 cm in total length were found only in siBIOciation with A. rigidifolius. They were found in these habitats throughout lb® year. A total of 600 plants of A. rigidifolius was introduced to a site of 10 m® In the same stream devoid of vegetation. At the point of introduction two inclemic species, namely Belontia signata (size 1.5 - 6.0 cm, 14±2.33 fish / hffit) and Puntius titteya (size 1.5 - 3.0 cm, 6+1.1 fish / net) were observed at lb® site of introduction.
    [Show full text]
  • Flora.Sa.Gov.Au/Jabg
    JOURNAL of the ADELAIDE BOTANIC GARDENS AN OPEN ACCESS JOURNAL FOR AUSTRALIAN SYSTEMATIC BOTANY flora.sa.gov.au/jabg Published by the STATE HERBARIUM OF SOUTH AUSTRALIA on behalf of the BOARD OF THE BOTANIC GARDENS AND STATE HERBARIUM © Board of the Botanic Gardens and State Herbarium, Adelaide, South Australia © Department of Environment, Water and Natural Resources, Government of South Australia All rights reserved State Herbarium of South Australia PO Box 2732 Kent Town SA 5071 Australia J. Adelaide Bot. Gard. 1(1) 55-59 (1976) A SUMMARY OF THE FAMILY LYTHRACEAE IN THE NORTHERN TERRITORY (WITH ADDITIONAL COMMENTS ON AUSTRALIAN MATERIAL) by A. S. Mitchell Arid Zone Research Institute, Animal Industry and Agriculture Branch, Department of the Northern Territory, Alice Springs, N.T. 5750. Abstract This paper presents a synopsis of the nomenclature of the family Lythraceae in the Northern Territory. Keysto the genera and species have been prepared. The family Lythraceae has been neglected in Australian systematics, andas a result both the taxonomy and nomenclature are confused. Not since the early work of Koehne (1881, 1903) has there been any major revision of the family. Recent work has been restricted to regional floras (Polatschek and Rechinger 1968; Chamberlain 1972; Dar 1975), with Bentham's Flora (1886) being the most recenton the family in Australia. From a survey of the available literature the author has attempted to extract all the relevant names applicable to Australian material and to present them solelyas a survey of the nomenclature of the group. No type material has beenseen, and the only material examined was that lodged in the Department of the Northern Territory Herbariaat Alice Springs (NT) and Darwin (DNA).
    [Show full text]
  • International Phd PLANT HEALTH TECHNOLOGIES and PROTECTION of AGROECOSYSTEMS XXVII CYCLE 2012-2014 Molecular Characterization Of
    International PhD PLANT HEALTH TECHNOLOGIES AND PROTECTION OF AGROECOSYSTEMS XXVII CYCLE 2012-2014 Molecular characterization of Rhizoctonia spp. isolates and sustainable approaches to control Rhizoctonia diseases in ornamental nursery This thesis is presented for the degree of Doctor of Philosophy by PIETRO TINDARO FORMICA COORDINATOR TUTOR PROF. C. RAPISARDA PROF. G.POLIZZI This work was supported by MIUR project PON01_01611 (SO.PRO.ME.: Sustainable production of Potted Plants in Mediterranea Environment) Contents 1. The genus Rhizoctonia ................................................................................................. 1 1.1. Introduction .......................................................................................................... 1 1.2. Anastomosis group (AG) of Rhizoctonia solani and BNR and molecular analysis . 3 1.3. Systematics of Rhizoctonia species ....................................................................... 7 Genus Thanatephorus [Rhizoctonia s. str.] ...................................................................... 7 Genus Ceratobasidium [binucleate Rhizoctonia (BNR)] .................................................. 9 1.4. Biology .............................................................................................................. 12 1.5. Pathogenicity and hosts....................................................................................... 15 1.5.1. Seed decay .................................................................................................. 15 1.5.2.
    [Show full text]
  • Aponogeton Pollen from the Cretaceous and Paleogene of North America and West Greenland: Implications for the Origin and Palaeobiogeography of the Genus☆
    Review of Palaeobotany and Palynology 200 (2014) 161–187 Contents lists available at ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo Research paper Aponogeton pollen from the Cretaceous and Paleogene of North America and West Greenland: Implications for the origin and palaeobiogeography of the genus☆ Friðgeir Grímsson a,⁎, Reinhard Zetter a, Heidemarie Halbritter b, Guido W. Grimm c a University of Vienna, Department of Palaeontology, Althanstraße 14 (UZA II), Vienna, Austria b University of Vienna, Department of Structural and Functional Botany, Rennweg 14, Vienna, Austria c Swedish Museum of Natural History, Department of Palaeobiology, Box 50007, 10405 Stockholm, Sweden article info abstract Article history: The fossil record of Aponogeton (Aponogetonaceae) is scarce and the few reported macrofossil findings are in Received 15 January 2013 need of taxonomic revision. Aponogeton pollen is highly diagnostic and when studied with light microscopy Received in revised form 4 September 2013 (LM) and scanning electron microscopy (SEM) it cannot be confused with any other pollen types. The fossil Accepted 22 September 2013 Aponogeton pollen described here represent the first reliable Cretaceous and Eocene records of this genus world- Available online 3 October 2013 wide. Today, Aponogeton is confined to the tropics and subtropics of the Old World, but the new fossil records show that during the late Cretaceous and early Cenozoic it was thriving in North America and Greenland. The Keywords: Alismatales late Cretaceous pollen record provides important data for future phylogenetic and phylogeographic studies Aponogetonaceae focusing on basal monocots, especially the Alismatales. The Eocene pollen morphotypes from North America aquatic plant and Greenland differ in morphology from each other and also from the older Late Cretaceous North American early angiosperm pollen morphotype, indicating evolutionary trends and diversification within the genus over that time period.
    [Show full text]
  • Identification Guide of Invasive Alien Species of Union Concern
    Identification guide of Invasive Alien Species of Union concern Support for customs on the identification of IAS of Union concern Project task ENV.D.2/SER/2016/0011 (v1.1) Text: Riccardo Scalera, Johan van Valkenburg, Sandro Bertolino, Elena Tricarico, Katharina Lapin Illustrations: Massimiliano Lipperi, Studio Wildart Date of completion: 6/11/2017 Comments which could support improvement of this document are welcome. Please send your comments by e-mail to [email protected] This technical note has been drafted by a team of experts under the supervision of IUCN within the framework of the contract No 07.0202/2016/739524/SER/ENV.D.2 “Technical and Scientific support in relation to the Implementation of Regulation 1143/2014 on Invasive Alien Species”. The information and views set out in this note do not necessarily reflect the official opinion of the Commission. The Commission does not guarantee the accuracy of the data included in this note. Neither the Commission nor any person acting on the Commission’s behalf may be held responsible for the use which may be made of the information contained therein. Reproduction is authorised provided the source is acknowledged. Table of contents Gunnera tinctoria 2 Alternanthera philoxeroides 8 Procambarus fallax f. virginalis 13 Tamias sibiricus 18 Callosciurus erythraeus 23 Gunnera tinctoria Giant rhubarb, Chilean rhubarb, Chilean gunnera, Nalca, Panque General description: Synonyms Gunnera chilensis Lam., Gunnera scabra Ruiz. & Deep-green herbaceous, deciduous, Pav., Panke tinctoria Molina. clump-forming, perennial plant with thick, wholly rhizomatous stems Species ID producing umbrella-sized, orbicular or Kingdom: Plantae ovate leaves on stout petioles.
    [Show full text]
  • Downloaded from the WORLDCLIM Database (Hijmans Et Al
    Drivers of Macrophyte Assemblages in South African Freshwater Systems THESIS Submitted in fulfilment of the requirements for the degree DOCTOR OF PHILOSOPHY at Rhodes University By Grant Douglas Martin January 2013 i Abstract Abstract Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to find out the distribution and diversity of the species present, imported to, and traded in South Africa. Numerous submerged indigenous and invasive macrophyte locality records were collected during field surveys, of which many were first time records. Pet stores and aquarist trading activities were identified as potential vectors for the spread of submerged macrophytes through online surveys and personal interviews. These results highlighted the potential these species have for continuing to enter, and spread within South African water bodies. Maximum Entropy (MAXENT) is a general-purpose method used to predict or infer distributions from incomplete information, and was used here to predict areas suitable for the establishment of five of these invasive macrophytes. Many systems throughout South Africa, particularly those in the subtropical coastal regions, were found to be climatically suitable for the establishment of Elodea canadensis Michx., Egeria densa Planch., Hydrilla verticillata (L.f.) Royle (all Hydrocharitaceae), Myriophyllum spicatum L.
    [Show full text]