Biodiversity in Byron Shire - Byron Shire Council

Biodiversity in Byron ShireAn introduction to the biodiversity of Byron Shire and to thelegislative basis provided for its conservation by theNSW Threatened Species Conservation Act.

Biodiversity is the variety of life on earthBiodiversity is recognised at many differentlevels of organization, from the genetic throughthe species to the ecosystem.It consists of all the plants, the animals andthe micro-organisms, their constituent genes,their populations and the communities andecosystems of which they form a part.A common measure of biodiversity is at thespecies level. It is usual for vascular plantsand vertebrate animals to be the focus ofbiodiversity assessments as these tend to bethe best known groups of organisms.4

Byron Shire is at the centre of the wet subtropics bioregionWet subtropics bioregionThe wet subtropics is the Australian bioregioncomprising south-eastern Queensland andnorth-eastern NSW. On a national scale ofbiodiversity richness, the wet subtropics liesequal second, exceeded only by the wettropics of northern Queensland and equal withthe south-western corner of Western Australia.Wanganui GorgeMinyon FallsWet subtropics vertebrate richnessThe wet subtropics has the highest diversity of marsupials and microchiropteranbats of all Australian bioregions. It also has the equal highest diversity of frogs(with the wet tropics) and the second highest diversity of birds (exceeded onlyby the wet tropics).Koala (H. Bower)Lesueur’s FrogScaly-breasted LorikeetGolden-tipped Bat (P. German)6

Relict and endemic speciesThe wet subtropics has a high proportion ofrelict and endemic species. These arespecies with close links to the flora andfauna of the ancient continent of Gondwana,and species confined in their distributionsto the bioregion.Brush PepperbushSouthern Leaf-tailed GeckoAutumn and winter food resources for migratory and nomadic birds and flying-foxesThe bioregion is also of major significance to migratory and nomadic birds and flying-foxes from both higher andlower latitudes and higher elevations. A sequence of flowering wallum plants provides a continuous source of nectar,pollen and insects through autumn and winter months for these species at a time when such food resources are scarceelsewhere in eastern Australia.Little Friarbird Pink Bloodwood Grey-headed Flying-fox colony7

Biodiversity reflects influences of neogeographical and palaeogeographical factorsNeogeographical (or existing) factors contributing to biodiversity richnessByron Shire lies on the south-eastern edge of the Mt Warning shield volcano and is bounded to the east by a narrowcoastal plain that has experienced numerous relatively recent rises and falls in sea level.The range of physical features, including the interface with the sea, soils of high to low productivity, equitable climateand high rainfall all combine to produce a wide variety of habitats or niches supporting an equally wide variety ofplant and animal species.The area’s year-round growing season for plants, plus the availability of food resources for fauna from flowering andfruiting plants, are major contributors to this richness. Eucalypts, paperbarks, bottlebrushes, banksias and mistletoesproduce prolific quantities of nectar and pollen (particularly in autumn and winter) and many rainforest trees and vinesprovide an abundance of nutritious, fleshy fruits in different seasons.Byron, sea to the mountains, Nightcap Range to Cape ByronParallel dunes and swales at Tyagarah8

Mt Warning and the Mt Warning Caldera9

Biodiversity reflects influences of neogeographical and palaeogeographical factorsPalaeographical (or historical) factorscontributing to biodiversity richnessTumbunan biotaByron Shire is at the centre of one of two refugia for therelict Tumbunan biota, representative of the flora andfauna of the subtropical and temperate rainforests thatcovered much of the Australian continent in the early tomid-Tertiary period (30 million years ago). The otherrefugium is in the Atherton region of northern Queensland.Tumbunan species such as the Red Boppel Nut,Fletcher’s Frog and Fawn-footed Melomys are directdescendents of species of these early rainforests.Byron Shire also lies within an area of overlap betweenthe northern Torresian and southern Bassian biotas.Torresian biotaThe Torresian biota is represented by the flora andfauna of the hot, dry savannah grasslands and woodlandsof Queensland and the Northern Territory.Torresian species, typified by the Northern Banjo Frog,Brown Tree Snake and Common Planigale, occur mainlyin the drier coastal communities in Byron Shire.Subtropical rainforestFawn-footed MelomysScribbly Gum woodlandBrown Tree SnakeRed Boppel NutFletcher’s FrogNorthern Banjo FrogCommon Planigale10

Eastern FalsistrelleEastern SpinebillScarlet HoneyeaterBurton’s Snake-lizardOld-growth Blackbutt forestBrown-striped Marsh FrogEastern Blossom-batWhite-striped Freetail-batBassian biotaThe Bassian biota is characterised by the flora andfauna of the cool wet eucalypt forests of southeasternNSW, Victoria and Tasmania.Typical Bassian species present in the Shire includethe Brown-striped Marsh Frog, Eastern Spinebill andEastern Falsistrelle.Other biota that also extend into the wet subtropics,but with less influence, are the Irian and Eyrean.Irian biotaThe Irian biota, characteristic of lowland New Guinea,is represented in Byron Shire by species such as theScarlet Honeyeater and Eastern Blossom-bat. Irianspecies are present mainly in lowland rainforest andcoastal swamp forest habitats.Eyrean biotaThe Eyrean biota of arid inland Australia isrepresented in the Shire by species including Burton’sSnake-lizard and the White-striped Freetail-bat.These are mainly species of open habitats that havecolonised the area following the vegetation clearingthat has accompanied European settlement.11

Threatened species in Byron ShireThreatened Species Conservation ActThe legislative basis for biodiversity conservation in NSW is provided by theThreatened Species Conservation (TSC) Act of 1995.Byron Shire, at the centre of the wet subtropics, has close to the highest numberof threatened species and communities in the State. This is primarily the result ofpalaeogeographical or historical factors (refer to previous section).Almost 70 threatened flora species and over 90 threatened fauna species havebeen recorded in the Shire. These include many rare species, species with restrictedranges including some endemic to the region, and species reaching the southern ornorthern limits of their distribution in eastern Australia.Sooty Owl (D. Hollands)Smooth Davidsonia Durobby Loveridge’s Frog12

Rare rainforest speciesRare species listed under the TSC Act occurring in Byron Shire include a numberendemic to the bioregion and are typically relict rainforest species with ancientlineages (representative of the Tumbunan biota). Examples are the SmoothDavidsonia, Durobby, Loveridge’s Frog and Sooty Owl.Species reaching their distributional limitsSpecies reaching the southern limits of their distribution in the region arepredominantly Torresian and Irian species such as the Marbled Frogmouth andEastern Tube-nosed Bat. Species reaching their northern limits of distributionin the region are characteristically Bassian species that include the EasternPygmy-possum and Southern Myotis.Eastern Tube-nosed Bat (P. German)Marbled Frogmouth Southern Myotis Eastern Pygmy-possum13

Threatened communities in Byron ShireLittoral rainforest, Brunswick Heads Nature ReserveSwamp sclerophyll forest, Billinudgel Nature ReserveEndangered ecological communitiesThe TSC Act recognises threatened communities as well asspecies, with many of the listed endangered ecological communities(EECs) occurring in the Shire. These are concentrated along the coastand on floodplains, reflecting the areas most severely impacted by pastclearing for agriculture. Such areas are now under additional pressuresfrom residential and tourist development and associated infrastructure, withfurther impacts from weeds and introduced animals.Coastal EECs widespread in Byron Shire include coastal saltmarsh,Swamp Oak floodplain forest, littoral rainforest, freshwater wetlands oncoastal floodplains and swamp sclerophyll forest on coastal floodplains.Further inland, EECs commonly occurring comprise lowland rainforest,lowland rainforest on coastal floodplain, river-flat eucalypt forest oncoastal floodplains and subtropical coastal floodplain forest.EECs of more limited occurrence are Byron Bay dwarf graminoid clayheath, which is restricted to the Cape Byron area, and Themeda grasslandon seacliffs and coastal headlands, found mainly at Cape Byron andBroken Head.Subtropical coastal floodplain forest14

Localised extinctions and key threatening processesThe TSC Act also recognises major threats to biodiversity conservation whichare listed as key threatening processes (KTPs). These are the processes thatcause extinctions of local populations and which ultimately lead toextinctions of species.Several bird and mammal species are known to have suffered populationlosses in Byron Shire since European settlement including Coxen’s Fig-parrot,Rufous Scrub-bird, Spotted-tailed Quoll and Yellow-bellied Glider. Themain KTPs responsible for these losses were the widespread clearing ofnative vegetation for agricultural purposes last century and the associatedalteration to the natural flow regimes of rivers, streams, floodplains andwetlands. Unfortunately both processes have continued through to presenttimes due to increasing urbanisation, particularly in coastal areas.Additional threats of increasing concern are the result of plant and animalintroductions such as the invasion of native plant communities by Bitou Bushand Boneseed, the invasion, establishment and spread of Lantana, theinvasion and establishment of the Cane Toad and predation by theEuropean Red Fox and by feral cats.Spotted-tailed Quoll (N. Brothers)Clearing and draining coastal wetlands, Byron BayCane Toad15