Notes On Native Orchids In Hanmer Forest

Transcription

1 32 Notes On Native Ochids In Hanme Foest Bian Molloy Landcae Reseach NZ Ltd., PO Box 69, Lincoln Intoduction My intoduction to the ochids o Hanme Foest occued in 1974 when I assisted the New Zealand Foest Sevice to descibe the native plants at selected points along the newlyconstucted Mt Isobel Walk (Molloy 1974). This inomation was included in a booklet on the Hanme Foest Walks, published a yea late (McCaskill & Johns 1975). Although most o this wok concened native vegetation, seveal visits wee made to the vaious walks in the exotic oests. About that time the pesence o native ochids in these oests was beginning to aouse attention, especially among membes o the Cantebuy Botanical Society who have visited the aea on seveal occasions (e.g., Elde & Mooe 1973). The impotance o Hanme Foest as an ochid habitat was bought into shape ocus by the discovey thee o an Austalian ochid, believed to be Chiloglottis gunnii, in Novembe 1981 by Gant Bawden o the New Zealand Foest Sevice (Johns & Molloy 1983, Molloy & Johns 1983). This was the ist ecod o this Austalian ochid in New Zealand and it stimulated the seach o this migant elsewhee. Subsequently the same ochid was ound unde beech oest in the Richmond Range Foest Pak in 1981 by Helen Rainoth o the Wellington Botanical Society (A.P. Duce pes, comm.), and unde Pinus niga at Iwatahi, Kaingaoa Foest in 1985 by Loma Gey, Tauanga Ochid Society (M. Gibbs pes. comm.). Until now this ochid was thought to be Chiloglottis gunnii Lindley, known in Austalia as the common bid ochid. Extensive studies o Chiloglottis in Austalia by David Jones have shown that thee ae seveal distinct taxa included unde the name Chiloglottis gunnii. One o these, Chiloglottis valida D. Jones is descibed as new (Jones, 1991) and specimens om Hanme, Richmond Range Foest Pak and Iwatahi have been conimed as the same species (D.L. Jones, pes, comm., 1991). Chiloglottis gunnii is now consideed to be a Tasmanian endemic o esticted distibution (Jones 1991). Fom inomation passed on to me by Gant Bawden, and om my own expeience at Hanme, it became clea that stands o seveal exotic conies, paticulaly those planted in the ealy 19s suppoted unusually lage numbes o native ochids. These notes summaise inomation gatheed on ochids at Hanme om 1982 onwads. Not all the exotic stands have been examined and to that extent the notes ae incomplete. Rathe, I have concentated on those aeas whee ochids have been (and in some cases still ae) abundant. Geneal distibution o ochids The distibution o native ochids within old stands o conies at Hanme is summaised in Table 1.

2 33 Table 1: Distibution o native ochid species in dieent conie plantation stands. Fequency o occuence is indicated by symbols: ab = abundant, = equent, o = occasional, and = ae. Ochid species Laix decidua Pinus niga* Pinus pondeosa Gastodia mino Gastodia cunninghami i Chiloglottis conuta Chiloglottis valida Pteostylis banksii Coybas tilobus Micotis uniolia Caladenia lyallii Apoostylis biolia Thelymita longiolia Adenochilus gacilis Pteostylis aeolata o ab ' ab ab * No distinction is made between Austian pine (Pinus niga ssp. austiaca) and Cosican pine (Pinus niga ssp. laicio) as little i any dieence was noted in thei ochid populations. The main conies associated with native ochids at Hanme ae Euopean lach (Laix decidua), Cosican and Austian pines (Pinus niga) and westen yellow pine (Pinus pondeosa). The old lach stands (194, 195) in the Receation Aea, which includes the well known Foest Walk, seem most suitable o the small potato ochid, Gastodia mino, and the ecent Austalian migant, Chiloglottis valida. Old stands o Cosican and Austian pines ( ) ae also avoued by gastodias, but especially the spide ochid, Coybas tilobus, as well as seveal othes. The ome stands o westen yellow pine (1914) in compatments 2 and 13 in the easten pat o Hanme Foest wee the pime habitat o the bid ochid, Chiloglottis conuta, and the sole habitat o the slende oest ochid, Adenochilus gacilis, which gew in abundance. These and the adjoining stands o Cosican pine in these compatments wee easily the best ochid habitats at Hanme and suppoted the widest ange o ochids until the stands wee cleaed in Explanation As a habitat o oest ochids, some o the old stands o exotic conies at Hanme ae ideal. With tee densities om 811 stems/ha, these stands povide the shade, shelte and longtem stability needed o ochid establishment and epoduction. Aside om lach which is summegeen, the evegeen canopies o Cosican and Austian pines and westen yellow pine povide suicient shade to inhibit the establishment o most potential competitos o ochids, while allowing enough diuse light o ochid

3 34 gowth and epoduction. The egula lines and spacing o tees also povide a lage uniom aea o open spaces o ochids to colonise. An even moe impotant acto o ochids is the buildup o ungi in the litte layes associated with the continuous decomposition o allen leaves and cones, punings, and allen tees. Most ochids depend on ungi o seed gemination, etaining this dependence thoughout thei lives to a geate o lesse degee. The gastodias o example, lack chloophyll and ae entiely dependent on speciic ungi. Othe genea and species o teestial ochids with nomal geen leaves also have speciic ungal patnes, but ae capable o photosynthesis. These ungi inect the oots and hizomes o ochids as well as the swollen basal pat o thei stems. The ungi ae digested by the ochid cells and povide a ich souce o nutients. Fom he extensive studies o ou nongeen, stongly mycohizal ochids, Ella Campbell has suggested that Gastodia cunninghamii and Gastodia mino possibly obtain nutients om ungi ectotophic on the oots o associated tees and ae theeoe epipaasites (Campbell 1962, 1963). At Hanme howeve, both these species seem conined to ootee decomposing litte layes, especially otting stumps and logs. At Hanme, dieent conies poduce dieent amounts and kinds o litte which ae elected by coesponding dieences in litte and soil ph. This in tun detemines the kinds o ungi pesent and thei speciic ochid patnes. As a as I know, the ungi at Hanme have not been identiied systematically, but the inluence o the vaious conies is appaent even to the untained eye by the egula appeaance o dieent 'mushooms' and 'toadstools' (matue uiting bodies) ollowing autumn and sping ains, with the lach bolete and agaics being especially plentiul. Ochids ae not the only plants aected. Othe native and intoduced loweing plants such as Lageniea pumila and Mycelis mualis ae associated with speciic conies. This suggests that they too may have close mycohizal elationships with paticula ungi, o ae esponding to othe actos such as the degee o shading o soil ph. The climatic conditions thoughout Hanme Foest ae aily uniom, and the soils o the pevailing teaces and olling lands ae mapped as Ashwick soils, which ae silt loams, and stony loams with low natual etility. These conditions, while conducive to ochid development, ae unlikely to play a majo ole in detemining the local distibutions o ochids pesent at Hanme. The conies on the othe hand ae consideed the majo acto in this espect. Table 2 summaises inomation on the litte, ungi, soil and ph at the vaious sites examined. As can be seen, the deepest and most acid litte occus unde Pinus pondeosa, and thee is a dieence o almost two units o ph between the litte o this conie and Noway spuce (Picea abies) whee

4 35 Table 2: Litte, ungi, soil and ph at the vaious sites examined. Conie Species Pinus pondeosa Compatment 2 Compatment 13 I Pinus niga ssp. austiaca Compatment 3 I Laix decidua Compatment 3 Compatment 4 (Chiloglottis valida site) Pinus niga spp. laicio Compatment 2 I Picea abies Compatment 3 Bie Desciption o Litte, Fungi, and Soil 24 cm esh needles; 6 cm decomp. needles, cones etc., much white and yellow ungal hyphae; ove bown stony silt loam 34 cm esh needles; 4 cm decomp. needles, cones etc., much white ungal hyphae; ove geyish bown gitty silt loam 3 cm esh needles; 5 cm decomp. needles, cones etc., much white ungal hyphae; ove geyish bown stony silt loam 12 cm esh needles; 12 cm decomp. needles, cones etc., vey little white ungal hyphae; ove geyish bown stony silt loam 1 cm esh needles; 23 cm decomp. needles, cones etc., vey little white ungal hyphae; ove geyish bown stony silt loam. 2 cm esh needles; 23 cm decomp. needles, cones etc., much white ungal hyphae; ove bown stony silt loam 1 cm esh needles; 12 cm decomp. needles, wood etc., vey little yellow ungal hyphae; ove geyish bown stony silt loam Litte ph* Soil 1 ph* * ph was detemined with a Cambidge ph mete on the decomposed and patly decomposed litte layes and the uppemost mineal soils immediately beneath. no ochids wee ound. Fungi wee most pevalent unde Pinus pondeosa and the two subspecies o Pinus niga, and least o all unde Euopean lach and Noway spuce. Not supisingly, thee was less than a unit o ph

5 36 dieence among the soils immediately beneath these dieent littes and ungi extended into the topmost soil layes unde Pinus pondeosa and P. niga in paticula. Most o the ochids' hizomes, oots and tubes ae conined to the ungalich litte, with a ew like Coybas tilobus penetating the ungalinected soil. Conclusion Old stands o exotic conies at Hanme have poved to be some o the best habitats in the county o cetain native ochids though pehaps not as ich as those at Iwatahi, Kaingaoa Foest (Gibbs 1988). Impotant eatues o these stands which have attacted ochids ae; stand density (81 stems/ha) inhibiting competitos on the one hand and yet pemitting suicient light o ochid establishment on the othe, stand age (7787 yeas) allowing an uninteupted development o deep litte layes and a consequent buildup o the allimpotant mycohizal ungi, and the species o conie planted which in tun detemines the kind and quantity o litte, ungi and ochids pesent. In tems o ochid species divesity, the conies at Hanme can be ated in the ode Pinus niga (both subspecies), Pinus pondeosa and Laix decidua. Howeve, the last two ae the only known habitats in Hanme Foest o cetain ochids, including the ae (o New Zealand) migant om Austalia, Chiloglottis valida. Pio to elling in 199 and 1991 the stands o Pinus pondeosa and Pinus niga in Compatments 2 and 3 wee consideed the best ochid habitats at Hanme o the numbe and divesity o ochids pesent. On the othe hand, the stands o Pinus niga and Laix decidua in Compatments 3 and 4 o the Receation Aea ae little ineio and should be maintained o as long as possible. The colony o Chiloglottis valida emains vigoous and healthy and continues to expand beyond its boundaies mapped in It seems clea to me that some o the old conies in the Receation Aea have eached the stage whee individual stands ae thinning out o one eason o anothe ceating openings o othe plants to ente, thus making these new habitats less suitable o ochids. Othe pats have been windthown o elled in the past and eplanted with conie species and/o at densities less suitable o ochids. I undestand that it is now planned to havest small goups o old conies om this aea and to eplant in these gaps in ode to maintain this unique species planting as an amenity the public have come to enjoy. Povided the appopiate species ae eplanted, and at the appopiate densities, the ochids should continue to cycle though this aea. The main poblems could be the susceptibility o esidual stands to wind damage, and the continual ingess o undesiable plants, both native and intoduced. Given the ight habitats, I am conident the ochids at Hanme can look ate themselves. The majoity o species pesent ae selpollinating and sel

6 37 etilised and poduce abundant seed. Some, like Coybas tilobus, ely less on seed poduction but extend vegetatively with geat success. Ove the last ten yeas native ochids have become one o the moe unusual attactions o Hanme oest exceeding in numbes thei countepats in the suounding beech oests and shublands. With appopiate management it should be possible to maintain i not enhance this eatue. Reeences Campbell, E.O The mycohiza o Gastodia cunninghamii Hook.. Tansactions Royal Society o New Zealand, Botany 1, Campbell, E.O Gastodia mino Petie, an epipaasite o manuka. Tansactions Royal Society o New Zealand, Botany, 2,7381 Elde, Y. & Mooe, L.B What gows unde the oest at Hanme. Cantebuy Botanical Society Jounal 6,13 Gibbs, M Iwatahi: a native ochid eseve in exotic pine oest, New Zealand. The Ochadian 9(3), 4951 Johns, J. & Molloy, B Native Ochids o New Zealand. Reed, Wellington. Jones, D.L New taxa o Austalian Ochidaceae. Austalian Ochid Reseach 2,4344, Fig 54. McCaskill, L.W. & Johns, J.H The Hanme Foest Walks. New Zealand Foest Sevice, Wellington. Molloy, B.P.J Foest Walk Mt Isobel: The Vegetation and Floa. Botany Division DSIR Vegetation Repot Numbe 61. Molloy, B. & Johns, J Chiloglottis gunnii Lindley, a new ochid ecod o New Zealand. The Ochadian 7 (9),