Summary: Although the study of nutrition during the last forty years has received considerable attention, there are still fields of the science about which our knowledge is very incomplete. In this country, in particular, there is little information even about the gross chemical composition of our foodstuffs -- a subject which must surely form the basis of any dietry constituents present in foods is of value to anyone concerned with the planning of accurate diets, or the investigation of the nutritional status of a community. It is well known that the figures, even for carbohydrate, protein and fat, compiled by workers in different parts of the world, vary widely. In accurate work it would therefore be incorrect to use such figures which were compiled in another country. This must necessarily occur in New Zealand because at present no complete and systematic analysis of our foods had been made, and hence there are no comprehensive tables. Further-more, there are many native products for which there are neither comparable overseas figures nor any New Zealand analyses of constituents--Introduction.

Historically there has been considerable debate over the origin of karaka (Corynocarpus laevigatus J.R. et G. Forst.) In contrast, the extent and importance of pre-historic arboriculture in New Zealand has received little attention in the literature. This study reviews the ecology and ethnobotony of karaka and investigates its cultural and natural biogeography. Maori migration traditions frequently state that karaka was introduced to New Zealand. However, molecular evidence and finds of fossil seeds of the late Oligocene age show that karaka is endemic to New Zealand. Therefore, Maori traditions probably relate to the translocation and cultivation of karaka within the New Zealand region, for which there is abundant anecdotal evidence. Karaka fruits were a valuable addition to the Maori diet and were likely to have functioned as a replacement for traditional Polynesian precedents and entailed a rigorous regime of steaming and soaking to rid the kernal of its toxic elements. There is data to suggest selection for fruit size and/or nutritional value in cultivated karaka populations. A database of karaka distribution was compiled and populations classified as �cultural� or �unknown� on the basis of spatial association with archaeological sites. Groves classed as cultural were assumed to be cultivated or translocated by pre-historic Maori. Lack of effective seed dispersal by birds and the longevity of the trees, mean that the contemporary distribution of karaka provides a reasonable template for the extent of its prehistoric translocation and cultivation within New Zealand. Karaka has a distinct cultural and natural biogeography. The greatest overlap between cultural and unknown trees occurred in the northern North Island while the majority of trees in the lower North Island, and all trees in the South Island were classed as cultural. Prior to the arrival of Polynesians in New Zealand, karaka was probably restricted in distribution to the Northland/Auckland region. Its natural range was then extended by human translocation and cultivation to the lower North Island, South Island, Kermadec Islands, Chatham Islands and many other in-shore islands off New Zealand. Climate variables were fitted to the distribution data and discriminant analysis used to further test the classification of karaka into cultural and unknown populations. Significant differences were found in climatic parameters between groups. Cultural karaka were found in enviroments with greater solar radiation seasonality, higher evaporative demands and greater soil moisture deficits than unknown karaka. The climate profile of karaka is biased towards the same environmental correlates of pa and pit site locations, further indicating that karaka was a cultivated tree crop. It is concluded that the importance and extent of karaka arboriculture, and probably that of other endemic tree species currently restricted to the northern North Island of cultural karaka is biased towards the same environmental correlates of pa and pit site locations, further indicating that karaka was a cultivated tree crop. The extensive translocation of karaka by Maori means that it has the potential, with the application of molecular methods, to serve as a marker for prehistoric settlement and mobility. Preliminary work was begun on this aspect and a predictive model is presented of the possible relationships within and between populations of karaka. It is concluded that the importance and extent of karaka arboriculture, and probably that of other endemic tree species, has previously been overlooked. This has implications for our view of certain plant communities as unmodified by humans, and provides an impetus to protect surface vegetation as an integral part of some prehistoric archaeological sites.

Historically there has been considerable debate over the origin of karaka (Corynocarpus laevigatus J.R. et G. Forst.) In contrast, the extent and importance of pre-historic arboriculture in New Zealand has received little attention in the literature. This study reviews the ecology and ethnobotony of karaka and investigates its cultural and natural biogeography. Maori migration traditions frequently state that karaka was introduced to New Zealand. However, molecular evidence and finds of fossil seeds of the late Oligocene age show that karaka is endemic to New Zealand. Therefore, Maori traditions probably relate to the translocation and cultivation of karaka within the New Zealand region, for which there is abundant anecdotal evidence. Karaka fruits were a valuable addition to the Maori diet and were likely to have functioned as a replacement for traditional Polynesian precedents and entailed a rigorous regime of steaming and soaking to rid the kernal of its toxic elements. There is data to suggest selection for fruit size and/or nutritional value in cultivated karaka populations. A database of karaka distribution was compiled and populations classified as �cultural� or �unknown� on the basis of spatial association with archaeological sites. Groves classed as cultural were assumed to be cultivated or translocated by pre-historic Maori. Lack of effective seed dispersal by birds and the longevity of the trees, mean that the contemporary distribution of karaka provides a reasonable template for the extent of its prehistoric translocation and cultivation within New Zealand. Karaka has a distinct cultural and natural biogeography. The greatest overlap between cultural and unknown trees occurred in the northern North Island while the majority of trees in the lower North Island, and all trees in the South Island were classed as cultural. Prior to the arrival of Polynesians in New Zealand, karaka was probably restricted in distribution to the Northland/Auckland region. Its natural range was then extended by human translocation and cultivation to the lower North Island, South Island, Kermadec Islands, Chatham Islands and many other in-shore islands off New Zealand. Climate variables were fitted to the distribution data and discriminant analysis used to further test the classification of karaka into cultural and unknown populations. Significant differences were found in climatic parameters between groups. Cultural karaka were found in enviroments with greater solar radiation seasonality, higher evaporative demands and greater soil moisture deficits than unknown karaka. The climate profile of karaka is biased towards the same environmental correlates of pa and pit site locations, further indicating that karaka was a cultivated tree crop. It is concluded that the importance and extent of karaka arboriculture, and probably that of other endemic tree species currently restricted to the northern North Island of cultural karaka is biased towards the same environmental correlates of pa and pit site locations, further indicating that karaka was a cultivated tree crop. The extensive translocation of karaka by Maori means that it has the potential, with the application of molecular methods, to serve as a marker for prehistoric settlement and mobility. Preliminary work was begun on this aspect and a predictive model is presented of the possible relationships within and between populations of karaka. It is concluded that the importance and extent of karaka arboriculture, and probably that of other endemic tree species, has previously been overlooked. This has implications for our view of certain plant communities as unmodified by humans, and provides an impetus to protect surface vegetation as an integral part of some prehistoric archaeological sites.

The decline of kereru (Hemiphaga novaeseelandiae) may limit dispersal of large-seeded plants in New Zealand, but the consequences of this are unknown. I determined kereru disperser effectiveness by modelling seed dispersal distances (using seed retention times and movement patterns). Mean seed retention time was significantly longer for larger-seeded species, ranging from 37-181 minutes. Wild radiotracked kereru were sedentary, remaining at one location for up to 5.25 hours. The mean flight distance was 77 m and the maximum was 1, 457 m. Estimated mean seed dispersal distances for tawa (Beilschmiedia tawa), puriri (Vitex lucens), and fivefinger (Pseudopanax arboreus) were 95, 98, and 61 m respectively. Kereru dispersed 66-87% of ingested seeds away from the parent tree, with 79-88% of seeds dispersed <100 m and < 1% dispersed over 1,000 m. In a field seed-fate experiment, "pre-human" conditions (cleaned seeds, low density, away from parent, and protected from mammals) increased survival compared to "post-human" conditions (whole fruits, high density, under parent, not protected) for both taraire (Beilschmiedia tarairi; 15% vs. 2% survival to one year respectively) and karaka (Corynocarpus laevigatus; 60% vs. 11% to two years, respectively). Fruit diameter varied considerably within karaka, taraire, and tawa, although theoretically not enough for them to be swallowed by other birds. Nevertheless, other birds are reported to occasionally take fruits of nearly all large-seeded species. Small tawa seeds produced smaller seedlings in the glasshouse; therefore selection of only smaller seeds by alternative dispersers may negatively affect tawa recruitment. Kereru are generally not gape-limited, and fruit size preferences were independent of mean fruit size. Kereru provide effective dispersal by moving most seeds away from the parent, and enhancing seed and seedling survival. Therefore, both dispersal failure and introduced mammals negatively affect the regeneration of large-seeded trees in New Zealand.

The decline of kereru (Hemiphaga novaeseelandiae) may limit dispersal of large-seeded plants in New Zealand, but the consequences of this are unknown. I determined kereru disperser effectiveness by modelling seed dispersal distances (using seed retention times and movement patterns). Mean seed retention time was significantly longer for larger-seeded species, ranging from 37-181 minutes. Wild radiotracked kereru were sedentary, remaining at one location for up to 5.25 hours. The mean flight distance was 77 m and the maximum was 1, 457 m. Estimated mean seed dispersal distances for tawa (Beilschmiedia tawa), puriri (Vitex lucens), and fivefinger (Pseudopanax arboreus) were 95, 98, and 61 m respectively. Kereru dispersed 66-87% of ingested seeds away from the parent tree, with 79-88% of seeds dispersed <100 m and < 1% dispersed over 1,000 m. In a field seed-fate experiment, "pre-human" conditions (cleaned seeds, low density, away from parent, and protected from mammals) increased survival compared to "post-human" conditions (whole fruits, high density, under parent, not protected) for both taraire (Beilschmiedia tarairi; 15% vs. 2% survival to one year respectively) and karaka (Corynocarpus laevigatus; 60% vs. 11% to two years, respectively). Fruit diameter varied considerably within karaka, taraire, and tawa, although theoretically not enough for them to be swallowed by other birds. Nevertheless, other birds are reported to occasionally take fruits of nearly all large-seeded species. Small tawa seeds produced smaller seedlings in the glasshouse; therefore selection of only smaller seeds by alternative dispersers may negatively affect tawa recruitment. Kereru are generally not gape-limited, and fruit size preferences were independent of mean fruit size. Kereru provide effective dispersal by moving most seeds away from the parent, and enhancing seed and seedling survival. Therefore, both dispersal failure and introduced mammals negatively affect the regeneration of large-seeded trees in New Zealand.