Coprosma robusta

Identification

Species description

Coprosma Robusta is identified as large bushy shrub that could grow up to 6 meters ^[1]. Branches stout with no hair (New Zealand Conservation Net work, 2015). Domatia is a significant character (small holes on the back of the leaf at the intersection of veins) can be observed from Coprosmas and meanwhile different Coprosmas species can be classified according to stipules. ^[2] In this case, C. robusta's stipules are black, hairless and obtuse with slightly serrated margin that united at base ^[3]

Leaves

The glossy leaves of Coprosma robusta ranges from 5 to 12 centimeters long, with elliptic-oblong shape and acute or obtuse leaf apex and veins are obvious(Oliver, 1935). Different colours on leaf which is dark green on the blade and light green on the back (New Zealand Conservation Network, 2015). Leaved thick, midrib not raised on upper surface. ^[4]

Flower

Flowers are small and white, axillary, dense, 4 lobes and appearance are different in male and female. Male flowers are dense, glomerules with a campanulate shape corolla and have four stamens; female flowers are compound with tubular shape of corolla. Stigmas are obvious ^[5]. The best flowering period is between August and September ^[6].

Fruit

Fruits are often dark-orange red to red, oblong to narrow ovate drups ^[7]. The best fruting period is between April and May ^[8].

Geographic Distribution and habitat

Natural global range

Coprosma robusta is endemic to New Zealand ^[9]. However, it is gradually becoming naturalized at the south-east coast corner of Australia such as Victoria and Tasmania (Blood, 2001) and has been rated as a weed thread in such places ^[10].

New Zealand range

It is widely distributed over New Zealand in both North island and South Island. On Chatham Islands between Waitangi and Owenga, there is a small area where Coprosma robusta starts naturalizing ^[11]. They can often be observed naturally in lowland forest. Judging from the distribution map on New Zealand Plant Observation ^[12], the distribution of Coprosma robusta increases with the differentiation in lower altitude which means more C. robustas in North Island.

In Canterbury the karamu is found on Banks Penninsula in fragments of regenerating native bush and bush remnants. Additionally it is also found in forest margins and edges of the montane and lowland forests in the southern alps at the start of the Canterbury planes. Coprosma robusta can also be found in the urban environment of many Christchurch city green spaces (e.g. park like Riccarton Bush) ^[13].

Habitat preferences

C. robusta can be widely found near coastal, lowland and lower montane areas. It can also grow within shrub lands and expansive areas within dense trees such as lowland forest ^[14]. However, the population will become lesser in lowland forest such as beech and kahikatea forests ^[15]. Normally C. robusta is a hardy plant that can adapt to infertile soils, poorly drained and exposed lands. it could also grow in a large range of altitude varying from 0-1200 meters under full sun to shady, windy and frosty circumstances.

Life cycle/Phenology

As mentioned before, the flowering season of C. robusta is from winter (approximately from July) to summer (ends around December). Male and female flowers are separated which called dioecious. Seeds will be mature in around April and start germinating afterwards. The growing speed at this stage will be very high. Worth mentioning that the process of the reproduction of this plant starts from the germination of the seeds with enough sunlight and moisture ^[16]. According to Burrows (2005), it is less likely to create a soil seed bank that last long although there will be germination happens in a short period of time. Today Coprosma has evolved into at least 58 species, subspecies and varieties ^[17].

The seeds would be largely dispersed by birds when they eat the fruit and drop the seed down to the ground. Due to the hardy characteristics, it is easy growing from seed and is also identified as one of the most effective growing plant on open sites ^[18]. Again, as mentioned before, the best season for C. robusta's fruting is between April and May. It would finally grow up to six meters high and will normally act as a secondary succession plant during this process ^[19].

Diet / Prey / Predators

Diet

C. robusta is an extremely hardy plant that could grow from a large range environmental conditions from full sun to shady, from dry to moist. One distinct character that worth mentioning is that It could tolerate frost and wind. The mature fruit of C. robusta could endure a minimum temperature to -8°C and the leaves could endure a minimum temperature -7°C before it gets irretrievably damaged ^[20]. It is identified to gain the best growing condition in a certain level of moist soils ^[21] which is not too acid, although they have the ability of living in poor soils ^[22]. They can also be found in coastal conditions, lowland scrubs, swamps and rock associations ^[23].

Predators

Herbivorous mammal predators such as goats (Capra hircus) and deer (Cervus elaphus) has the most severe impact on C. robusta species with damaging the plant and seedlings such as hares (Lepus timidus) and rabbits (Oryctolagus cuniculus) that would eat the juvenile plants.(Brockie, 1992). According to the database in Encyclopedia of Life ^[24],additional herbivores that would consume energy from C. robusta are Batracomorphus, Batracomorphus adventitiosus, leafhoppers and Membracoidea.

Interaction

As mentioned before, birds will help C. robusta to disperse seeds such as native bellbird (Anthornis melanura), Tuis (Prosthemadera novaeseelandiae), indigenous silvereyes (Zosterops lateralis), adventive blackbirds (Turdus merula), and song thrushes (Turdus philomelos) ^[25]. Under birds' dispersal, the seeds could possibly travel a long way to somewhere under succession ^[26]. According to the database in Encyclopedia of Life ^[27], additional species that have interaction with C. robusta are Acalitus, Acalitus cottieri, Eriophyid mites, European greenfinch, goldfinch, grey-breated silvereye, honeteaters and so on.

Karamu and mychorrhizal fungi can make a symbiotic mutualism in roots system. Because mychorrhizal fungi can supply water and nutrients to plant. A experiment for coprosma robusta with adding sufficient solube phosphate into soil which aim to provide whether phosphorus useful to mycorrhizal. Numerous mycorrhizas of coprosma robusta grows larger in phosphorus soil than those with little or no infection, no added phosphate ^[28].

Parasites

C. robusta will sometimes act as a host plant to support other plant's growing including Posocarp,Totara and yellow-wood family^[29].

Cultural uses

Medicinal uses

Juvenile shoots can be applied to release inflammation or bladder problems by boiled to liquid and drunk. The leaves are believed by Maori having the ability to deal with kidney troubles and boiling the barks are used to stop stomache and vomiting. Both the leaves and the barks will be used in bath for medicinal mysterious reason ^[30].

Food supply

The mature berries of C. robusta can be eaten as a food resource as well as its leaves could be drunk as tea ^[31].

Dyes

C. robusta is rich in dying properties including alizarin and purpurin. Traditional Maori will make use of these dying matters to dye Phormium fiber to yellow ^[32]. Sometimes leaves of C. robusta will be put on stones and dye the food and preserve them after a hangi ^[33].

Traditions

Baptists will use the leaves in a ceremony and green C. robusta braches will be held by tohunga in tohi for newly born babies ^[34].

Revegetation and plantings

Coprosma robusta is noted for its quick bushy growth and for this reason is commonly cultivated and frequently used for revegetation projects ^[35]. Beside of the revegetation used, this shrub also highly used in urban form. People like to plant them for their beautiful flowers and cute orange-red fruits. They provide shelter for people to have rest and food for the wildlife, especially could be used for attracting birds like Fantails and Goldfinches.

Interesting facts

It is one of the first seven Coprosma species that be discovered and collected by Joseph Banks with Cook's voyage to New Zealand. At the very first time, Coprosma robusta was called Pelaphia lata ^[36].

In recent years, there is a report showing the sex ratio of Coprosma robusta in the Riccarton Bush in Christchurch. The sex ratio of population of Coprosma robusta is female-biased with 70% of the flowering plants being female. This female-biased ratio differs from the few other counts of sex ratios in New Zealand species of Coprosma. That could be influenced by a number of factors, including the pollen and seed fecundity of the two sexes and factors affecting their sexual maturity and mortality. That is interesting because the Coprosma robusta often male-biased in sex ratios. This differential survival of the sexes in long-lived species is usually attributed to differences in reproductive effort between male and female plants. In particular, the energy cost of producing ovules and fruit in female plants is greater than the cost of male flowers producing pollen. Female-biased sex ratios also occur as a consequence of differential fertilization and genetic differentiation of sex chromosomes ^[37].

1. ↑ Poole, A.L.; Adams, N.M. (1990). Trees and Shrubs of New Zealand. Wellington, New Zealand: DSIR Publishing. 
2. ↑ Dawson, J; Lucas, R (2000). Nature Guide to the New Zealand Forest. Auckland, New Zealand: Random House. 
3. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
4. ↑ Poole, A.L.; Adams, N.M. (1990). Trees and Shrubs of New Zealand. Wellington, New Zealand: DSIR Publishing. 
5. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
6. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
7. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
8. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
9. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
10. ↑ "Weed Risk Assessment: Coprosma robusta" (PDF). Tasmanian Government. Retrieved 1 April 2015. 
11. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
12. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
13. ↑ Burrows, C.J. (1995). "Germination behaviour of the seeds of the New Zealand species". New Zealand Journal of Botany 33 (2): 257–264. 
14. ↑ "Coprosma robusta". New Zealand Plant Conservation Network. Retrieved 1 April 2015. 
15. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
16. ↑ Heenan, P.B.; Molloy, B.P.J; Bicknell, R.A.; Luo, C. (2003). "Levels of apomictic and amphimictic seed formation in a natural population of Comprosma robusta (Rubiaceae) in Riccarton Bush, Christchurch, New Zealand". New Zealand Journal of Botany 41 (2): 287–291. 
17. ↑ Eagle, A (1986). Eagle’s trees and shrubs of New Zealand volume one revised. Auckland, New Zealand: Collins books. 
18. ↑ Williams, P.A.; Buxton, R.P. (1989). New Zealand Journal of Ecology 12 (95): 101.  Missing or empty |title= (help)
19. ↑ Williams, P.A.; Buxton, R.P. (1989). New Zealand Journal of Ecology 12 (95): 101.  Missing or empty |title= (help)
20. ↑ Bannister, P; Lee, W. "The frost resistance of fruits and leaves of some Coprosma species in relation to altitude and habitat". New Zealand Journal of Botany 27: 477–479. 
21. ↑ "Weed Risk Assessment: Coprosma robusta" (PDF). Tasmanian Government. Retrieved 1 April 2015. 
22. ↑ Mckay, A.C.; McGill, C.R.; Fountain, D.W.; Southward, R.C. (2002). "Seed dormancy and germination of a panel of New Zealand plants suitable for re‐vegetation". New Zealand Journal of Botany 40 (3): 373–382. 
23. ↑ Clarke, A (2007). The Great Sacred Forest of Tane: a natural pre-history of Aotearoa. Auckland, New Zealand: Reed Books. 
24. ↑ "Coprosma robusta". Encyclopedia of Life. Retrieved 1 April 2015. 
25. ↑ Karl, B.J; Williams, P.A (1996). "Fleshy fruits of indigenous and adventive plants in". New Zealand Journal of Ecology 20: 127–145. 
26. ↑ Burrows, C.J. (1995). "Germination behaviour of the seeds of the New Zealand species". New Zealand Journal of Botany 33 (2): 257–264. 
27. ↑ "Coprosma robusta". Encyclopedia of Life. Retrieved 1 April 2015. 
28. ↑ Baylis, G (1967). "Experiments on the ecological significance of phycomycetous mycorrhizas". New Phytologist 66 (2): 231–243. 
29. ↑ "Coprosma robusta". Encyclopedia of Life. Retrieved 1 April 2015. 
30. ↑ "Maori Plant Use: Coprosma Robusta". Landcare Research. Retrieved 1 April 2015. 
31. ↑ "Maori Plant Use: Coprosma Robusta". Landcare Research. Retrieved 1 April 2015. 
32. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
33. ↑ "Maori Plant Use: Coprosma Robusta". Landcare Research. Retrieved 1 April 2015. 
34. ↑ "Maori Plant Use: Coprosma Robusta". Landcare Research. Retrieved 1 April 2015. 
35. ↑ Burrows, C.J. (1995). "Germination behaviour of the seeds of the New Zealand species". New Zealand Journal of Botany 33 (2): 257–264. 
36. ↑ Oliver, W.R.B (1935). The Genus Coprosma. Honolulu, Hawaii: The Museum. 
37. ↑ Heenan, P.B.; Molloy, B.P.J; Bicknell, R.A.; Luo, C. (2003). "Levels of apomictic and amphimictic seed formation in a natural population of Comprosma robusta (Rubiaceae) in Riccarton Bush, Christchurch, New Zealand". New Zealand Journal of Botany 41 (2): 287–291.