Flora of the Hawke’s Bay
Bruce Clarkson Programme Leader: People, Cities & Nature
Hawke’s Bay Ecological Restoration Workshop 2-3 November 2018 Unique Hawke’s Bay Environment
Hawke’s Bay has distinctive dry habitat that is: • rich in divaricating species • rich in threatened species • mistletoes • but low in epiphytes
Divaricating = having branches of wide angles that are intertangled
Threatened = at risk of extinction (to varying degrees)
Epiphytes = plants that perch on other plants
Mistletoes = hemi-parasitic plants that live on other plants Phil Bendle Upper Waikura River Valley Plants
Ferns
Dicot herbs other than composites Dicot trees
Dicot shrubs
Sedges
Dicot lianes and trailing plants
Grasses
Monocot herbs (others)
Rushes
Gymnosperm trees
Composite herbs 183 species Divaricates of the Upper Waikura River Valley Plants
20 species 1
8 11
Gymnosperm trees and shrubs Dicot Trees Phil Bendle Dicot Shrubs Threatened species of Hawke’s Bay
Geoff Walls, DOC, 1998: Kakabeak – Clianthus puniceus
Bernard Spragg Pirita – Yellow mistletoe – Alepis flavida
Bernard Spragg Hector’s tree daisy – Olearia hectorii
DOC Pua o Te Rēinga - Wood rose - Dactylanthus taylorii
R. Stanley Heart-leaved kohuhu - Pittosporum obcordatum
B Clarkson Kōwhai ngutu kākā - Kakabeak – Clianthus puniceus
Absoluteandy88 Mahia hunt for tāwhiri karo – Pittosporum cornifolium
Current and historic locations Predicted environmental distribution
Coprosma pedicellata Coprosma pedicellata Coprosma pedicellata C. pedicellata population structure
20 18 16 14 12 10 8 6
Number of stems Numberof 4 2 0 0.0.- 0.5- 1.0- 1.5- 2.0- 2.5- 3.0- 3.5- 4.0- 4.5- 5.0- 5.5- 6.0- 6.5- 7.0- 7.5- 8.0- 0.49 0.99 1.49 1.99 2.49 2.99 3.49 3.99 4.49 4.99 5.49 5.99 6.49 6.99 7.49 7.99 8.49 Height class (m) C. pedicellata height vs basal area
9 8 7 6 5 4 3
Stem height (m) 2 1 0 0 5 10 15 20 25 Stem basal diameter (cm) Coprosma pedicellata: Predicted loss using demographic data • Youngest adult = 3.5 cm = 13 years old • Life span <100 years; oldest recorded is 85 years • Adult death rate = 0.75 per year = 35 years all adults would be dead • Largest juvenile (+ 3 cm per year growth rate) would take 55 years to reach adulthood • Juvenile death rate = 18 per year = 1.5 years all juveniles would be dead • Remove browsing completely (+ 33 cm per year growth rate) would take largest juveniles only 5 years to reach adulthood
Pittosporum obcordatum: an experiment in the inheritance of a juvenile divaricating form Pittosporum obcordatum F1 hybrid with P. crassifolium & F2 hybrids with P.obcordatum & P. tenuifolium
THREATENED PLANTS: APPLIED AUTECOLOGY • Pittosporum obcordatum a small tree in the family Pittosporaceae (Pittosporum) • Corybas carsei a swamp dwelling helmet orchid (Orchidaceae) • Melicytus drucei a swamp dwelling shrub in the family Violaceae (violet) • Brachyglottis perdicioides a shrub in the family Asteraceae (daisy) • Caleana minor an orchid (Orchidaceae) found in geothermal areas • Coprosma pedicellata a small tree in the family Rubiaceae (coffee) Plant ecology 1
• Ecology- the science of interrelationships between living organisms and their environment • Autecology- interrelationships between the plant individual and its environment or the adaptations and behaviour of individual species or populations in relation to their environment • Adaptation- a peculiarity of structure, physiology, or behaviour that aids in fitting an organism to its environment Plant ecology 2
• The study of plant community relationships by contrast to autecology is termed synecology • Subdivisions of autecology: demecology (speciation), population ecology and demography (the regulation of population size), physiological ecology (ecophysiology) and genecology (genetics) Plant ecology 3
• Autecological classification of plants emphasises the relationship of a plant with its environment and focuses on the adaptations which enable it to survive this environment. This has been formalised by Raunkiaer and others as life form classification. • 5 basic life forms on the basis of the position of the buds or organs from which new shoots develop after an unfavourable season References
• Clarkson, B. D.; Clarkson, B. R. 1994: Ecology of an elusive endemic shrub, Pittosporum obcordatum Raoul. New Zealand Journal of Botany 32: 155-168. • Molloy, B. P. J.; Clarkson, B. D. 1996: A new, rare Melicytus (Violaceae) from New Zealand. New Zealand Journal of Botany 34: 431-440. • Clarkson, B.D.; Downs, T.M.; Clarkson, B.R. 2004: Predicting extinction of the northernmost Coprosma pedicellata population, Waikura Stream, Gisborne. NZ Natural Sciences 28: 1-8.