Scientific name: Agathis montana de Laubenfels 1969
Synonyms: Salisburyodendron montana (de Laub.) A.V.Bobrov & Melikyan
Common names: Mount Panié kauri, Kaori du mont Panié (French), Dayu Biik
Description
Tree to 15(-20) m tall, with relatively short trunk to 1 m in diameter. Bark smooth and light brown at first, weathering grayish brown and flaking in thin sheets and later in small, irregular scales to reveal reddish brown fresh patches, often streaked or blotched with fresh or dried resin. Crown dense to open, broadly vase-shaped with a flattened top made up stout, contorted branches bearing tufts of branchlets. Branchlets green from the beginning, densely clothed with foliage. Leaves dark green above, paler but without a waxy film beneath, 6-8 cm long (to 10 cm in juveniles), 1.5-2.5 cm wide (to 3 cm in juveniles), widest near the middle (or sometimes a little before the middle in juveniles), tapering fairly rapidly to the roundly triangular to rounded tip and to the roundly wedge-shaped base on a short petiole 1-6 mm long. Pollen cones 4-5 cm long, 8-10 mm thick, with five or six pairs of larger, clasping, sterile scales at the base and attached directly in the leaf axils without a stalk or on a very short stalk 1-2 mm long. Each pollen scale with five to eight pollen sacs and a rounded external face. Seed cones not conspicuously waxy at maturity, round but noticeably longer than wide about 8-9 cm long and 6-7 cm thick. Seed scales turned up at the outer rim but without a large, tonguelike projection. Seed body about 10 mm long and 7 mm wide, the larger wing 18-20 mm by 14-15 mm, the smaller one roundly triangular, projecting about 4-5 mm.
Agathis montana forms a single subpopulation spread over a narrow altitudinal band on three peaks located within 20 km of each other along a single ridgeline. Restricted to and common along the summits of the Mount Panié range (hence the names), from Mount Ignambi to Mount Painé in northern New Caledonia, with a few stands in the Roches d’ Ouaïème just across the Ouaïème River to the south. Forming the canopy of the summit cloud forest, alone or in combination with other species, on soils derived from sedimentary rocks; 900-1,630 m.
Conservation Status
Red List Category & Criteria: Critically Endangered
Agathis montana is a long lived conifer (generation length may be ca 500 years) restricted to a single subpopulation in one location in the higher elevations of the Mt. Panié range in Province Nord, New Caledonia. The extent of occurrence is estimated to be 90 km2 and a population decline and habitat degradation have been observed over the last five years and is projected to continue. Agathis montana is therefore considered Critically Endangered under the B1 criterion.
Twenty percent of the trees within the area of a monitoring programme are already dead: 5% of mature monitored trees died between October 2012 and February 2014, suggesting a projected population reduction of 80% within the next 21 years and a likelihood of there being no mature trees left in 100 years. An assessment under Criterion A4 was considered but has not been used due to the small sample size and the limited time period for which the situation has been monitored.
Several factors may be contributing to the decline and habitat degradation. Foraging invasive pigs disturb soil leading to increased erosion of the thin and vulnerable soil as well as the death of the fine feeder roots of the kauri trees causing stress. Feral pigs are also known to be vectors of pathogens which may be attacking the weakened trees. A Phytophthora species with affinities to the one linked to extensive die back of New Zealand Agathis australis has been recorded on Agathis montana trees that are showing evidence of decline. Recorded increases in temperature and potentially altered cloud regime may lead to an increase in water stress. Recent regional droughts, concurrent with the recorded increase in temperatures and combined with the impact of feral pigs and Phytophthora may be jointly causing the decline.
Conservation management includes pig control and is due to start in 2015. Further research into other causes of the decline is needed.
Most trees grow in mono-specific stands in the canopy above 1,300 m on the SW slope and above 1,200 m asl on the NE slope. Below that, only a few isolated individual trees are seen down to 1,000 m asl (de Laubenfels 1972). This elevation range seems to correspond to a cloud layer that envelopes this part of the mountain most of the time.
Agathis montana forms near-monospecific stands that dominate the canopy between 10 and 25 meters above ground. It probably plays a significant role (=keystone species) in filtering sunlight and maintaining humidity and thus creating a unique habitat. Most other plant species grow up to 3-5 meters, creating a very thick understorey (Tron and Texier 2013). Several micro-endemic plant species (Wulff 2013) and insects (Grandcolas et al. 2008) are known from this habitat, one of the most important for micro-endemism in New Caledonia (Wulff 2013) and now internationally recognized as a "Key Biodiversity Area" (Conservation International 2011).
One recently dead tree of 80 cm diameter was estimated to be aged 1,100-1,300 years based on Carbon 14 dating methods (GNS Science 2012). Life-span is therefore suspected to be well over 1,000 years (Tron and Texier 2013). Based on this information and assuming linear growth, annual diameter growth is expected to be 0.7 mm/year. Fruiting is irregular and few observation have been made; however, maturity may be reached when trees are 20-30 cm DBH. Generation length may be ca 500 years. Regeneration is very dense in the understorey, but very few of them reach maturity (Texier 2013). From casual observations, regeneration looks sparse or may even be absent when mature Agathis montana are dead: most dead trees are in eroded areas.
Agathis montana produces a dense, fine and highly ectomycorrhized feeder-roots matt within the first 5 cm of the soil (Tron and Texier 2013).The soil is silty and shallow (<50 cm) and seems to be the product of the bedrock (schist) and litter degradation. It is therefore particularly sensitive to erosion. Agathis montana does not grow on purely rocky substrate outcrops.
Four threats and factors are suspected to be involved in the decline of this species (Tron and Texier 2013):
1) Feral pigs: in searching for food in the soil, feral pigs disturb moss, litter and the surface horizon that contains the fine feeder roots of kauris, creating a first stress to kauris. In 2012, within the 14 random plots 95.6% trees had pig uprootings, with an average of 8.5 uprootings per tree. Dead feeder-roots can be recognized as dead when they appear grey rather than the normal red when they are alive and healthy. Many dead feeder roots have been recorded in areas damaged by pigs. This disturbance also causes significant erosion, sometimes down to the bedrock, which permanently damages roots, especially the fine feeder-roots; many anchoring roots now emerge out of the ground. In eroded areas where many kauris have died, other vegetation looks less dense, vital and varied. Trees may then suffer water and mineral stresses, likely becoming more vulnerable to pests and pathogens and overall leading to dieback of the trees and eventually death. Feral pigs are also known to spread soil-borne diseases, including Phytophthora cinnamomi in New Zealand (Krull et al. 2012). The first introduction of pigs to New Caledonia dates back to the arrival of James Cook's fleet in 1774 and several releases have occurred since then throughout New Caledonia. Local indigenous people report a recent (ca over the last 10-20 years) population increase in feral pigs, possibly in relation to limitations on the ownership of guns and ammunition and changes in hunting practices that have led to a reduction in hunting effort and range. Similar changes have been reported in many other parts of New Caledonia.
2) Disease: an unidentified Phytophthora species was found in July 2012 (PlantWise 2014). While its exact taxonomic position is not yet known, it is known that it is not Phytophthora cinnamomi and has been identified as a member of the same clade that includes the Phytophthora linked to extensive dieback in New Zealand Agathis australis forests (Phytophthora Taxon Agathis). It is currently uncertain whether it is a native or introduced, and whether it is a primary or secondary pathogen. Biosecurity measures have never been requested at the entrance of Mt. Panié reserve.
3) Insects: two bark beetles species (most likely Hylurgus sp. and Hypocryphalus sp. Hulcr pers. comm.) were found in July-October 2012 on trees showing signs of dieback. Their exact taxonomic position is not yet known and it is uncertain if they are native or introduced, or are acting as primary or secondary pests.
4) Climate change: an analysis of local weather records (from a weather station based 10 km away, at sea level) shows a temperature increase of 1°C over the last 40 years and a significant drought in the period 2003-2007 (Casola and Tron 2013). Similar increases have been reported across New Caledonia (Maitrepierre et al. 2008). Temperature increase may alter the cloud regime possibly leading to a lowering of the cloud upper limit (areas above 1,300 m regularly emerge from the clouds) and thereby exposing the Agathis forests to a different microclimate with less humidity. Higher temperatures and less humidity may cause a significant water stress on Agathis montana; the genus Agathis is considered particularly vulnerable to it (Delzon and Brodribb in review). In French Polynesia, feral pigs move and forage more intensively at higher altitude during droughts, where they also have a significant impact on soil and vegetation (J.F. Buteau pers. comm.). Water stressed trees would be more vulnerable to pests and pathogens, possibly leading to die-back and eventually to death.
Local indigenous guides and local senior botanists report that a thick moss layer (20-50 cm thick) used to cover large parts of the ground: it is now restricted to small and isolated patches. During the 1970s, the French army felled a significant number of trees on the summit of Mt. Panié and built a wooden hut in order to facilitate helicopter and troop exercises: many old dead trees are clustered around this clearing. Some local indigenous people consider that taboos involving Mt. Panié have been breached and are one of the causes of the decline.
Agathis montana is called “Dayu Biik” in Némi and Fwaî, two local dialects. The translates as “strong and flexible Kauri” in reference to its ability to withstand strong winds. Its is also considered by some indigenous people with land rights on Mt. Panié as the guardian of the place and trees have a cultural importance in relation to the spirits of the local people's ancestors. Dayu Biik is also the name of a secondary, but very sacred peak within the Mt. Panié range. Several legends refer to the place where Agathis montana grows.
The indigenous organization in charge of the management of Mt. Panié wilderness reserve, is named after Agathis montana. They hence have a key cultural responsibility in caring for that species in particular. Agathis montana is an iconic species, often displayed on pictures promoting New Caledonian biodiversity and landscape.
Along with other Agathis spp. its gum is used by local guides as fuel for campfires. Trees may be grown as ornamentals, but mostly in specialist collections.
Conservation of Agathis montana is a specific objective of the first Mt. Panié wilderness reserve management plan. Some resources have been allocated for pig control & yearly monitoring (Anonyme 2011) but these now seem insufficient. In 2012, implementation of Year 1 of the management plan involved the following activities; a field visit from Dr. Nick Waipara (Waipara 2012), sampling of tissues and pathogen identification (PlantWise 2014), tree architecture study (Texier 2013),establishment of monitoring plots and protocols (Texier 2013) and assessment of management options (Tron and Texier 2013). To date, pig control has been identified as the most realistic management option. Feral pig control should start in 2015 while other conservation strategies, including research are being considered. Mt Panié reserve contains ca 30% of A. montana's main range (ca 350 of 1,200 hectares). A wider community consultation was started in 2013 to mobilize all concerned stakeholders in agreeing an extension to the reserve so that appropriate conservation management can be undertaken at that scale.
References
- Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
- Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
- IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland
Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.
