150 Years of Ecological Change in Inland Eastern Australia

Total Page:16

File Type:pdf, Size:1020Kb

150 Years of Ecological Change in Inland Eastern Australia Degraded or just dusty?: 150 years of ecological change in inland eastern Australia Jennifer Lesley Silcock B. Environmental Management (Natural Systems & Wildlife) (Honours class I) A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland (2014) School of Biological Sciences ‘Remains of cow near a windmill, western Queensland’, Sidney Nolan (1952), part of Nolan’s drought series commissioned by The Courier Mail (National Library of Australia) (left) . ‘Mirrica Botanical (The Desert Garden)’, Jo Bertini (2012), part of the ‘Desert Garden’ collection depicting the eastern Simpson Desert blooming after exceptional summer rains (right) 0 ABSTRACT The ecological history of rangelands is often presented as a tale of devastation, where fragile drylands are irreversibly degraded through inappropriate land-use. There is confusion about how to recognise and measure degradation, especially in low productivity environments characterised by extreme natural variability and where abrupt management upheavals mean that there are few reference sites. These issues have important consequences for rangeland development and management programs, many of which are founded on a perception of serious and ongoing degradation from a former ‘natural’ state. In this thesis, I employ three approaches to assess degradation in inland eastern Australia, part of one of the largest desert landforms in the world and subject to recurring arguments about the cause and magnitude of landscape change since pastoral settlement 150 years ago: written historical records, grazing exclosures, and identification and surveys of rare and potentially sensitive elements of the flora. From the 1840s, the journals of European explorers provide the first written descriptions of inland Australia. In Chapter 2, I use this record to test prevailing paradigms relating to five key themes of environmental change: vegetation structure, fire regimes, waterhole permanence, macropod abundance and medium-sized mammal assemblages. 4500 observations from fourteen journals spanning twelve expeditions between 1844 and 1919 were geo-referenced. Careful evaluation of the record suggests little change in broad vegetation structure or waterhole permanence, running counter to prevailing paradigms. The sparse observations of fire suggest burning was infrequent, while macropods were apparently uncommon in semi-arid areas where they are abundant today. Systematic evaluation of the explorer record for a region can provide ecological insights that are difficult to obtain by other means. However, there are limitations inherent in the historical record and findings are necessarily broad. i In Chapter 3, I use long-term grazing exclosures to examine the impacts of cattle grazing on two widespread vegetation types. We measured herbaceous biomass and plant species richness and abundance at five 14-year-old exclosures in north-eastern South Australia. We did not detect any significant differences between grazed and ungrazed treatments in total species richness or abundance, life form richness or abundance, or herbaceous biomass. The dominance of ephemeral species confers resilience by limiting the development of strong feedbacks between grazing intensity and vegetation dynamics, meaning that the non- equilibrium paradigm best describes this grazing system. This chapter forms part of a series of three studies using exclosures to examine grazing impacts across three biogeographic regions. Exclosures encompass only a tiny area, meaning that rare or grazing-sensitive species may not be represented, or may have become locally extinct prior to the erection of exclosures. In Chapter 4, I identify rare and potentially sensitive elements of the western Queensland flora through a systematic examination of herbarium records and expert interviews. Five threat syndromes were identified, arising from the interaction of plant biology and threatening processes, and 60 potentially threatened species had been overlooked in the listing process. However, lack of data on distribution, abundance, population dynamics and threats precluded robust conservation assessments for most species. In particular, detecting genuine rarity and decline was confounded by extreme temporal variability, low collection effort spread over a vast area and poor understanding of threatening processes. Chapter 5 examines patterns of rarity in the flora of a semi-arid mountain range, the Grey Range, with a high concentration of rare species and 150 years of elevated grazing pressure. Habitat specialisation, reproductive biology and biogeographic history interact to create observed patterns of rarity, and there is no evidence that any species have become rare or restricted as a result of grazing. Species confined to barren plateaux, sheltered habitats and gidgee toeslopes represent relictual populations, and the association of rare plants with larger plateaux suggests local extinctions were more probable on smaller plateaux during Pleistocene climatic fluctuations. ii Chapter 6 presents the results of four years of targeted surveys for the candidate species identified in Chapter 4. Search effort and survey results were used to assess 91 species against international Red List criteria. One-third of species were widespread and abundant at least in certain seasons but had appeared rare due to sparse collections. The conservation status of 20 species, mostly newly-recognised species from restricted habitats, was upgraded and 14 remained listed due to having restricted areas of occupancy. The IUCN criterion that allows for listing of species due to extreme fluctuations (in combination with restricted and fragmented populations) is not justified for arid zones, where these fluctuations may actually confer resilience to grazing for short-lived forbs and geophytes. With the exception of 12 artesian spring species, continuing declines were documented for just six species. In Chapter 7, I bring together my results and those of previous studies to provide a critical evaluation of the extent and magnitude of ecological change in inland eastern Australia. There is no evidence of unidirectional change in vegetation structure, irreversible degradation or loss of plant species, although some palatable species have declined at a landscape scale. It is apparent that some prevailing paradigms have become entrenched despite lack of empirical evidence. However, many medium-sized mammals have declined dramatically or become extinct since European settlement, while large macropod numbers have increased in the semi- arid zone. Management actions and areas requiring further research are discussed. The approach presented here, incorporating the historical record, comparison of sites with different management histories and targeted surveys for rare and potentially sensitive species, can be used to assess degradation in drylands with abrupt changes in management and contentious ecological narratives. iii Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my research higher degree candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the General Award Rules of The University of Queensland, immediately made available for research and study in accordance with the Copyright Act 1968 . I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material. Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis. iv Publications during candidature Peer-reviewed papers forming part of thesis (See below for details of contributions for each paper.) Silcock, J.L., Piddocke, T.P. & Fensham, R.J. 2013, ‘Illuminating the dawn of pastoralism: evaluating the record of European explorers to inform landscape change’, Biological Conservation 159:321-331. Silcock, J.L. & Fensham, R.J. 2012, ‘Arid vegetation in disequilibrium with livestock grazing: evidence from long-term exclosures’, Austral Ecology 38:57-65. Silcock, J.L., Fensham, R.J. & Martin, T.G. 2011, ‘Assessing rarity and threat in an arid-zone flora’, Australian Journal of Botany , 59:336-350. Silcock, J.L. & Fensham, R.J. 2014, ‘Specialised and stranded: habitat specialisation and biogeographic history determine the rarity of species in a semi-arid mountain range’, Journal of Biogeography , 41:2332-2343. Silcock, J.L. & Fensham, R.J. 2015, ‘Lost in time and space: re-assessment of conservation status in an arid-zone flora through targeted field survey’, Australian Journal of Botany (accepted December 2014). Peer-reviewed papers not forming
Recommended publications
  • Lake Pinaroo Ramsar Site
    Ecological character description: Lake Pinaroo Ramsar site Ecological character description: Lake Pinaroo Ramsar site Disclaimer The Department of Environment and Climate Change NSW (DECC) has compiled the Ecological character description: Lake Pinaroo Ramsar site in good faith, exercising all due care and attention. DECC does not accept responsibility for any inaccurate or incomplete information supplied by third parties. No representation is made about the accuracy, completeness or suitability of the information in this publication for any particular purpose. Readers should seek appropriate advice about the suitability of the information to their needs. © State of New South Wales and Department of Environment and Climate Change DECC is pleased to allow the reproduction of material from this publication on the condition that the source, publisher and authorship are appropriately acknowledged. Published by: Department of Environment and Climate Change NSW 59–61 Goulburn Street, Sydney PO Box A290, Sydney South 1232 Phone: 131555 (NSW only – publications and information requests) (02) 9995 5000 (switchboard) Fax: (02) 9995 5999 TTY: (02) 9211 4723 Email: [email protected] Website: www.environment.nsw.gov.au DECC 2008/275 ISBN 978 1 74122 839 7 June 2008 Printed on environmentally sustainable paper Cover photos Inset upper: Lake Pinaroo in flood, 1976 (DECC) Aerial: Lake Pinaroo in flood, March 1976 (DECC) Inset lower left: Blue-billed duck (R. Kingsford) Inset lower middle: Red-necked avocet (C. Herbert) Inset lower right: Red-capped plover (C. Herbert) Summary An ecological character description has been defined as ‘the combination of the ecosystem components, processes, benefits and services that characterise a wetland at a given point in time’.
    [Show full text]
  • To: Standing Committee on Economics, House of Representatives, Parliament of Australia
    SUBMISSION 34 1 Submission on Wild Rivers Bill 2010. To: Standing Committee on Economics, House of Representatives, Parliament of Australia, Re: Inquiry into Indigenous economic development in Queensland and review of Wild Rivers Bill 2010. From: Emeritus Professor John Holmes, School of Geography, Planning and Environmental Management, The University of Queensland, 4072. Date: 7 February, 2011. Two issues are central in assessing the merit of the Wild Rivers declarations. These relate to property rights and to economic impacts, primarily for Indigenous people. This submission is directed towards economic issues. There are two questions requiring informed consideration. The first is to provide realistic appraisals of the immediate and longer-term economic opportunities in the declared catchments and riparian zones. The second is to determine the likely economic impacts of the declarations, including both positive and negative outcomes, particularly for the Indigenous people. Regional Economic Appraisal: Cape York Peninsula There are inescapable geographical impediments militating against broadscale agricultural and pastoral enterprises and against capital-intensive tourism on the peninsula. The peninsula lacks any lands of significant agricultural potential, comparable with extensive tracts in the Ord, Fitzroy or Douglas-Daly districts, capable of meeting any major impulses towards rural development in the tropical savannas. Environmental constraints are reinforced by formidable accessibility barriers, where, again, the peninsula is disadvantaged when compared with these other districts. There is a steep accessibility gradient towards the peninsula’s northern cul- de-sac. Inaccessibility leads to prohibitive cost burdens on agricultural inputs, notably fuel and fertilisers and also on marketing of outputs. In addition to the cost burdens, there are logistic impediments in ensuring reliability, frequency and timeliness in transport systems, reinforced during the Wet Season.
    [Show full text]
  • Sturt National Park
    Plan of Management Sturt National Park © 2018 State of NSW and the Office of Environment and Heritage With the exception of photographs, the State of NSW and the Office of Environment and Heritage (OEH) are pleased to allow this material to be reproduced in whole or in part for educational and non-commercial use, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. Specific permission is required for the reproduction of photographs. OEH has compiled this publication in good faith, exercising all due care and attention. No representation is made about the accuracy, completeness or suitability of the information in this publication for any particular purpose. OEH shall not be liable for any damage that may occur to any person or organisation taking action or not on the basis of this publication. All content in this publication is owned by OEH and is protected by Crown Copyright. It is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) , subject to the exemptions contained in the licence. The legal code for the licence is available at Creative Commons . OEH asserts the right to be attributed as author of the original material in the following manner: © State of New South Wales and Office of Environment and Heritage 2018. This plan of management was adopted by the Minister for the Environment on 23 January 2018. Acknowledgments OEH acknowledges that Sturt is in the traditional Country of the Wangkumara and Malyangapa people. This plan of management was prepared by staff of the NSW National Parks and Wildlife Service (NPWS), part of OEH.
    [Show full text]
  • Australia: State of the Environment 1996: Chapter 4
    Chapter 4 . Biodiversity ‘Still Flying’ from the painting of a Wandering Albatross by Richard Prepared by Weatherly. Denis Saunders (Chair), CSIRO Division of Wildlife and Ecology Andrew Beattie, Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University Susannah Eliott (Research Assistant/Science Writer), Centre for Science Communication, University of Technology, Sydney Marilyn Fox, School of Geography, University of New South Wales Burke Hill, CSIRO Division of Fisheries Bob Pressey, New South Wales National Parks and Wildlife Service Duncan Veal, Centre for Biodiversity and Bioresources, School of Biological Sciences, Macquarie University Jackie Venning, State of Environment Reporting, South Australian Department of Environment and Natural Resources Mathew Maliel (State of the Environment Reporting Unit member), Department of the Environment, Sport and Territories (Facilitator) Charlie Zammit (former State of the Environment Reporting Unit member), Department of the Environment, Sport and Territories (former Facilitator) 4-1 . Australia: State of the Environment 1996 . Contents Introduction. 4-4 Pressure . 4-7 Human populations . 4-9 Urban development . 4-9 Tourism and recreation . 4-9 Harvesting resources and land use. 4-10 Fisheries . 4-10 Forestry . 4-11 Pastoralism. 4-12 Agriculture . 4-12 Introduced species . 4-16 Vertebrates . 4-16 Invertebrates. 4-17 Plants. 4-18 Micro-organisms. 4-20 Native species out of place . 4-20 Pollution . 4-21 Mining . 4-22 Climate change . 4-22 State . 4-23 The state of ecosystem diversity . 4-23 Biogeographic regionalisations for Australia . 4-23 Ecosystem diversity. 4-26 The state of species diversity. 4-30 Number and distribution of species . 4-31 Status of species .
    [Show full text]
  • Outline of Angiosperm Phylogeny
    Outline of angiosperm phylogeny: orders, families, and representative genera with emphasis on Oregon native plants Priscilla Spears December 2013 The following listing gives an introduction to the phylogenetic classification of the flowering plants that has emerged in recent decades, and which is based on nucleic acid sequences as well as morphological and developmental data. This listing emphasizes temperate families of the Northern Hemisphere and is meant as an overview with examples of Oregon native plants. It includes many exotic genera that are grown in Oregon as ornamentals plus other plants of interest worldwide. The genera that are Oregon natives are printed in a blue font. Genera that are exotics are shown in black, however genera in blue may also contain non-native species. Names separated by a slash are alternatives or else the nomenclature is in flux. When several genera have the same common name, the names are separated by commas. The order of the family names is from the linear listing of families in the APG III report. For further information, see the references on the last page. Basal Angiosperms (ANITA grade) Amborellales Amborellaceae, sole family, the earliest branch of flowering plants, a shrub native to New Caledonia – Amborella Nymphaeales Hydatellaceae – aquatics from Australasia, previously classified as a grass Cabombaceae (water shield – Brasenia, fanwort – Cabomba) Nymphaeaceae (water lilies – Nymphaea; pond lilies – Nuphar) Austrobaileyales Schisandraceae (wild sarsaparilla, star vine – Schisandra; Japanese
    [Show full text]
  • Vegetation and Floristics of Naree and Yantabulla
    Vegetation and Floristics of Naree and Yantabulla Dr John T. Hunter June 2015 23 Kendall Rd, Invergowrie NSW, 2350 Ph. & Fax: (02) 6775 2452 Email: [email protected] A Report to the Bush Heritage Australia i Vegetation of Naree & Yantabulla Contents Summary ................................................................................................................ i 1 Introduction ....................................................................................................... 1 1.1 Objectives ....................................................................................... 1 2 Methodology ...................................................................................................... 2 2.1 Site and species information ......................................................... 2 2.2 Data management ......................................................................... 3 2.3 Multivariate analysis ..................................................................... 3 2.4 Significant vascular plant taxa within the study area ............... 5 2.5 Mapping ......................................................................................... 5 2.6 Mapping caveats ............................................................................ 8 3 Results ................................................................................................................ 9 3.1 Site stratification ........................................................................... 9 3.2 Floristics ......................................................................................
    [Show full text]
  • Heritage of the Birdsville and Strzelecki Tracks
    Department for Environment and Heritage Heritage of the Birdsville and Strzelecki Tracks Part of the Far North & Far West Region (Region 13) Historical Research Pty Ltd Adelaide in association with Austral Archaeology Pty Ltd Lyn Leader-Elliott Iris Iwanicki December 2002 Frontispiece Woolshed, Cordillo Downs Station (SHP:009) The Birdsville & Strzelecki Tracks Heritage Survey was financed by the South Australian Government (through the State Heritage Fund) and the Commonwealth of Australia (through the Australian Heritage Commission). It was carried out by heritage consultants Historical Research Pty Ltd, in association with Austral Archaeology Pty Ltd, Lyn Leader-Elliott and Iris Iwanicki between April 2001 and December 2002. The views expressed in this publication are not necessarily those of the South Australian Government or the Commonwealth of Australia and they do not accept responsibility for any advice or information in relation to this material. All recommendations are the opinions of the heritage consultants Historical Research Pty Ltd (or their subconsultants) and may not necessarily be acted upon by the State Heritage Authority or the Australian Heritage Commission. Information presented in this document may be copied for non-commercial purposes including for personal or educational uses. Reproduction for purposes other than those given above requires written permission from the South Australian Government or the Commonwealth of Australia. Requests and enquiries should be addressed to either the Manager, Heritage Branch, Department for Environment and Heritage, GPO Box 1047, Adelaide, SA, 5001, or email [email protected], or the Manager, Copyright Services, Info Access, GPO Box 1920, Canberra, ACT, 2601, or email [email protected].
    [Show full text]
  • Track-Based Monitoring for the Deserts and Rangelands of Australia
    Track-based monitoring for the deserts and rangelands of Australia Richard Southgate and Katherine Moseby Envisage Environmental Services Ecological Horizons June 2008 for the Threatened Species Network at WWF-Australia Executive Summary This document outlines a broad-scale nationally-coordinated program for monitoring threatened and invasive species in the inland deserts and rangelands of Australia. The program uses a track-based monitoring technique which has been developed after extensive work with Indigenous groups in arid Australia and is well suited to engage the skills of Indigenous people and provide meaningful employment. There is a pressing need to understand the broad-scale population trends and status of remnant threatened species and the distribution and abundance of invasive species in arid Australia. Animal populations are often highly dispersed, elusive and challenging to monitor and some species are producing considerable impact on agriculture and biodiversity. The proposed technique produces multi-species occupancy data and these data are foundational in studies of distribution and range and the study of animal invasions. The data are statistically robust and relatively inexpensive to produce. The technique is simple to apply and monitoring can be conducted on a broad-scale and is well-suited to the isolated, large, sandy areas of the interior. A draft monitoring protocol and data sheet is provided. To improve the validity of data it is proposed that a training and accreditation scheme would ensure the validity of data and allow skilled traditional owners to train others in their community. Track-based monitoring is not a new technique, indigenous groups have been using animal sign for millennia, and more recently scientists have also adopted this method particularly for monitoring introduced predators.
    [Show full text]
  • Enabling the Market: Incentives for Biodiversity in the Rangelands
    Enabling the Market: Incentives for Biodiversity in the Rangelands: Report to the Australian Government Department of the Environment and Water Resources by the Desert Knowledge Cooperative Research Centre Anita Smyth Anthea Coggan Famiza Yunus Russell Gorddard Stuart Whitten Jocelyn Davies Nic Gambold Jo Maloney Rodney Edwards Rob Brandle Mike Fleming John Read June 2007 Copyright and Disclaimers © Commonwealth of Australia 2007 Information contained in this publication may be copied or reproduced for study, research, information or educational purposes, subject to inclusion of an acknowledgment of the source. The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Water Resources. While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Australian Government does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. Contributing author information Anita Smyth: CSIRO Sustainable Ecosystems Anthea Coggan: CSIRO Sustainable Ecosystems Famiza Yunus: CSIRO Sustainable Ecosystems Russell Gorddard: CSIRO Sustainable Ecosystems Stuart Whitten: CSIRO Sustainable Ecosystems Jocelyn Davies: CSIRO Sustainable Ecosystems Nic Gambold: Central Land Council Jo Maloney Rodney Edwards: Ngaanyatjarra Council Rob Brandle: South Austalia Department for Environment and Heritage Mike Fleming: South Australia Department of Water, Land and Biodiversity Conservation John Read: BHP Billiton Desert Knowledge CRC Report Number 18 Information contained in this publication may be copied or reproduced for study, research, information or educational purposes, subject to inclusion of an acknowledgement of the source.
    [Show full text]
  • Southern Gulf, Queensland
    Biodiversity Summary for NRM Regions Species List What is the summary for and where does it come from? This list has been produced by the Department of Sustainability, Environment, Water, Population and Communities (SEWPC) for the Natural Resource Management Spatial Information System. The list was produced using the AustralianAustralian Natural Natural Heritage Heritage Assessment Assessment Tool Tool (ANHAT), which analyses data from a range of plant and animal surveys and collections from across Australia to automatically generate a report for each NRM region. Data sources (Appendix 2) include national and state herbaria, museums, state governments, CSIRO, Birds Australia and a range of surveys conducted by or for DEWHA. For each family of plant and animal covered by ANHAT (Appendix 1), this document gives the number of species in the country and how many of them are found in the region. It also identifies species listed as Vulnerable, Critically Endangered, Endangered or Conservation Dependent under the EPBC Act. A biodiversity summary for this region is also available. For more information please see: www.environment.gov.au/heritage/anhat/index.html Limitations • ANHAT currently contains information on the distribution of over 30,000 Australian taxa. This includes all mammals, birds, reptiles, frogs and fish, 137 families of vascular plants (over 15,000 species) and a range of invertebrate groups. Groups notnot yet yet covered covered in inANHAT ANHAT are notnot included included in in the the list. list. • The data used come from authoritative sources, but they are not perfect. All species names have been confirmed as valid species names, but it is not possible to confirm all species locations.
    [Show full text]
  • Flora Survey on Hiltaba Station and Gawler Ranges National Park
    Flora Survey on Hiltaba Station and Gawler Ranges National Park Hiltaba Pastoral Lease and Gawler Ranges National Park, South Australia Survey conducted: 12 to 22 Nov 2012 Report submitted: 22 May 2013 P.J. Lang, J. Kellermann, G.H. Bell & H.B. Cross with contributions from C.J. Brodie, H.P. Vonow & M. Waycott SA Department of Environment, Water and Natural Resources Vascular plants, macrofungi, lichens, and bryophytes Bush Blitz – Flora Survey on Hiltaba Station and Gawler Ranges NP, November 2012 Report submitted to Bush Blitz, Australian Biological Resources Study: 22 May 2013. Published online on http://data.environment.sa.gov.au/: 25 Nov. 2016. ISBN 978-1-922027-49-8 (pdf) © Department of Environment, Water and Natural Resouces, South Australia, 2013. With the exception of the Piping Shrike emblem, images, and other material or devices protected by a trademark and subject to review by the Government of South Australia at all times, this report is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. All other rights are reserved. This report should be cited as: Lang, P.J.1, Kellermann, J.1, 2, Bell, G.H.1 & Cross, H.B.1, 2, 3 (2013). Flora survey on Hiltaba Station and Gawler Ranges National Park: vascular plants, macrofungi, lichens, and bryophytes. Report for Bush Blitz, Australian Biological Resources Study, Canberra. (Department of Environment, Water and Natural Resources, South Australia: Adelaide). Authors’ addresses: 1State Herbarium of South Australia, Department of Environment, Water and Natural Resources (DEWNR), GPO Box 1047, Adelaide, SA 5001, Australia.
    [Show full text]
  • Biogeography and Diversification of Brassicales
    Molecular Phylogenetics and Evolution 99 (2016) 204–224 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev Biogeography and diversification of Brassicales: A 103 million year tale ⇑ Warren M. Cardinal-McTeague a,1, Kenneth J. Sytsma b, Jocelyn C. Hall a, a Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada b Department of Botany, University of Wisconsin, Madison, WI 53706, USA article info abstract Article history: Brassicales is a diverse order perhaps most famous because it houses Brassicaceae and, its premier mem- Received 22 July 2015 ber, Arabidopsis thaliana. This widely distributed and species-rich lineage has been overlooked as a Revised 24 February 2016 promising system to investigate patterns of disjunct distributions and diversification rates. We analyzed Accepted 25 February 2016 plastid and mitochondrial sequence data from five gene regions (>8000 bp) across 151 taxa to: (1) Available online 15 March 2016 produce a chronogram for major lineages in Brassicales, including Brassicaceae and Arabidopsis, based on greater taxon sampling across the order and previously overlooked fossil evidence, (2) examine Keywords: biogeographical ancestral range estimations and disjunct distributions in BioGeoBEARS, and (3) determine Arabidopsis thaliana where shifts in species diversification occur using BAMM. The evolution and radiation of the Brassicales BAMM BEAST began 103 Mya and was linked to a series of inter-continental vicariant, long-distance dispersal, and land BioGeoBEARS bridge migration events. North America appears to be a significant area for early stem lineages in the Brassicaceae order. Shifts to Australia then African are evident at nodes near the core Brassicales, which diverged Cleomaceae 68.5 Mya (HPD = 75.6–62.0).
    [Show full text]