Going back to the Source: The Ecosystem at Velskov
Climbing Rata by Soulquest Photography
We are actively restoring the original Ecosystem at Velskov, classified at WF11.
WF11 - Regional IUCN threat status: Endangered
This diverse forest ecosystem is commonly derived from logged kauri forest, occurring in warm and sub-humid–humid areas with rainfall 1000–2500mm. It is found predominantly on hill slopes with acidic leached soils (oxidic, ultic soils grading to podzols) where kauri occurs; more fertile (granular) soils have broadleaved species in gullies (Molloy 1998).
Where kauri and podocarp trees are present, soil fertility is in decline, especially on more stable sites (Burns & Leathwick 1996). Canopy species can be long-lived, and wind-throw and associated soil disturbance caused by subtropical cyclones are significant factors influencing forest regeneration and soil rejuvenation cycles (Wardle 1991; Meurk 1995).
Distribution: Northern North Island, from north of Hamilton and Tauranga to North Cape, including Great Barrier and Little Barrier Islands. Predominantly from near sea level to 350m, and up to 500–600m on the Coromandel Peninsula, Great Barrier and Little Barrier islands. There are also good examples of this ecosystem type in the Waitākere Ranges, Rodney District and on the North Shore.
Characteristic native flora: A diverse forest related to topographical and edaphic factors, with a wide range of canopy and sub-canopy species. Kauri predominantly (but not exclusively) occurs on ridge crests and hill-slopes, with broadleaved species more abundant in gullies.
Podocarp trees are widespread, with rimu, tōtara, thin-barked tōtara, miro and tānekaha more common on ridges, while kahikatea is more common in gullies and on alluvial terraces.
Broadleaved trees are often dominant in gullies and include taraire, tawa, tōwai, kohekohe, pūriri, northern rātā, pukatea and rewarewa. Altitudinal variants occur, with taraire and kohekohe locally more abundant at lower altitudes, while tawa and tōwai are more abundant at higher altitudes (McKelvey & Nicholls 1959; Nicholls 1976; Esler 1983; Burns & Leathwick 1996). Tōwai is locally absent from most of the Auckland region (McKelvey & Nicholls 1959).
Characteristic native fauna: Pre-human era: Kauri, podocarp, and broadleaved forest would have supported a diverse range of invertebrates, amphibians, reptiles, birds and bats (Atkinson & Millener 1991; Worthy & Holdaway 2002). Forest productivity would have been enhanced by the nutrients brought ashore by burrowing seabirds (Atkinson & Millener 1991; Smith et al. 2011).
Several species of moa, adzebill, brown and little spotted kiwi were probably present, along with forest-inhabiting ducks, raptors, snipe and flightless rails (Atkinson & Millener 1991; Worthy & Holdaway 2002; Holdaway et al. 2013). Large-fruited trees, such as pūriri, tawa, taraire and kohekohe, would have attracted species such as kākāpō, kākā, kererū, saddleback, huia, kōkako and piopio.
Moa, in addition to browsing leaves and twigs, would have eaten fallen fruits, while nectivorous reptiles and birds would have had an almost year-round nectar supply (Whitaker 1987; Clout & Hay 1989; Kelly et al. 2010). Insectivores would have included tuatara, skinks, geckos, small rails, snipe, owls, owlet-nightjar, wrens, robin, tomtit, whitehead, fantail, grey warbler, saddleback, huia, piopio and bats (Atkinson & Millener 1991; Worthy & Holdaway 2002).
Present: These forests are an important habitat for kererū, which usually need good quantities of fruit to breed (Pierce & Graham 1995), while geckos, kākā, tūī and bellbird take abundant nectar in season (Whitaker 1987; Clout & Hay 1989; Anderson 2003; Kelly et al. 2010).
Kauri, podocarp, broadleaved forests support the more common native bush birds, e.g. morepork, kingfisher, shining cuckoo, fantail, grey warbler, tūī and silvereye, with others such as kākāriki species, long-tailed cuckoo, rifleman, whitehead, robin, tomtit, hihi, bellbird, saddleback and kōkako on larger pest-free islands.
Tree cavities in species such as pūriri and pōhutukawa in places free of mammalian predators provide shelter, roosting and nesting sites for geckos, kākā, kākāriki, hihi, saddleback and bats.
Introduced species, such as white cockatoo, rosella, blackbird, chaffinch and myna, are also present.
Key processes and interactions: The major factors influencing the composition of this forest are fertility, drainage and altitude (Burns & Leathwick 1996).
Over millennia, cyclical subtropical storm-induced disturbance is required to facilitate the regeneration of many canopy species, especially kauri and podocarps (Wardle 1991). Native birds, particularly kererū and tūī, are important for the pollination and seed dispersal of a wide range of canopy and sub-canopy species (Clout & Hay 1989).
Threats: Significant human-induced modification from both Māori and European settlement has occurred. The remaining areas have mostly been heavily logged, especially for kauri and podocarp trees, and many extant examples have also been burnt (Conning 2001).
Pest mammals are significant threats, with possums, goats and rats especially causing the decline of palatable flora (Payton 2000) and vulnerable fauna (Innes et al. 2010). Possums and goats in combination have the potential to cause canopy collapse and regeneration failure of a wide range of species within this ecosystem.
Closed-canopy intact examples are highly resistant to weed invasion, though shade-tolerant ground-covers (e.g. tradescantia, African clubmoss and wild ginger) and trees and shrubs (e.g. monkey apple, privet and palms) readily invade. Many kauri forests are suffering from kauri dieback, caused by the invasive pathogen Phytophthora agathidicida (commonly known as PTA).
Kauri dieback is now an emerging serious threat to the species and wider ecosystem (Jamieson et al. 2014). In the Auckland region, the Hunua Ranges and Little Barrier Island contain the largest stands of kauri forest that remain free of kauri dieback.
Source: Ecosystems of Auckland