grassy weeds in pastoral systems - context, needs and directions
DESCRIPTION
Grassy weeds in pastoral systems - CONTEXT, NEEDS AND DIRECTIONS. weeds are everywhere. pastoral systems are often weedy. perception is important. Weeds of pastoral systems. Weeds of significance to the grazing industries of Australia MLA and Weeds CRC 2002 . - PowerPoint PPT PresentationTRANSCRIPT
Grassy weeds in pastoral systems
- CONTEXT, NEEDS AND DIRECTIONS
• weeds are everywhere
• perception is important
• pastoral systems are often weedy
Weeds of pastoral systems
• Weeds of significance to the grazing industries of AustraliaMLA and Weeds CRC 2002
• 119 weed species referenced
• 48 species or groups of species of greatest significance
• 9 grasses or groups of grasses:African lovegrassbrowntop bent grassChilean needle grassCoolatai grassgrader grassannual grasses – e.g. barley grassperennial mission grassrat’s tail grassesserrated tussock
Grassy weeds – where have they come from?
INTRODUCED GRASSES
DELIBERATE ACCIDENTAL
ORNAMENTALAGRICULTURE
Grassy weeds – where have they come from?
CSIRO Plant Introduction Service 1924-2000crops 197 speciesother C3 grasses 1067other C4 grasses 992TOTAL 2250
No. of grass accessions introduced fromSub-Saharan Africa 3490Asia 2052N&E Europe 3786Mediterranean 2934North America 4559Central America 298South America 2000Other/unknown 660TOTAL 19779
Some deliberately introduced weedy grasses
Pennisetum – 5 speciesincluding P. polystachion (mission grass)
Nassella – 9 species, including N. trichotoma and N. neesiana
Andropogon virginicusBromus spp.Eragrostis curvula (African lovegrass)Hyparrhenia hirta (Coolatai grass)Sporobolus indicus (rat’s tail grass)Themeda quadrivalvis (grader grass)Vulpia bromoides
Weedy grasses and the Weeds CRC
• Landscape Management ProgramTask 1: Habitat approach Task 2: Functional group approachTask 3: The science of biological control
• Weeds CRC in its second round since 2001
• 3 research programs(1) Management of new incursions(2) Cropping systems(3) Landscape management
• Task 3 deals with four functional groups(i) invasive rangeland shrubs(ii) bird-dispersed weeds(iii) aquatic weeds(iv) unpalatable grasses
Unpalatable grass weeds in context
• Prominence
• Impact
• Threat
• Intractability
• Conflict