techniques within the traditional harvest are considered. Learning and social mechanisms for the titi harvest are based on the foundation of tikanga (protocol) and kaitiakitanga (environmental guardianship), but are demonstrably adaptive, building the resilience and social-ecological sustainability of this culturally-fundamental harvest.Keywords adaptive co-management; lore and law; Puffinus griseus; tikanga; tītī harvesting; Traditional Ecological Knowledge Abstract In a fast-changing world, successful communication of traditional cultural principles and practices of guardianship and stewardship across generations is more important than ever before. This study investigates knowledge and learning in relation to the last large-scale customary harvest of a seabird in New Zealand, the titi (Puffinus griseus), by Rakiura Maori. Semi-directed interviews were conducted with 20 titi-harvesting elders. We sought firstly to identify the key knowledge-holders and mechanisms for the transmission of ecological knowledge, as well as the cultural and spiritual beliefs interwoven with harvest practice. Secondly, we sought to identify modern challenges to traditional pathways of learning, and the changing roles of knowledge holders in the harvesting community. Traditional approaches, including observation, hands-on experience, and storytelling, continue as the main mechanisms for knowledge transmission. Awareness of ancestors (tupuna) and taboo improve compliance of accepted harvesting practices, reinforcing the connection of Rakiura Maori to the harvesting islands and fostering a strong conservation ethic. However, modern needs and pressures appear to threaten the transmission of knowledge between successive generations. The effects, both positive and negative, of the adoption of modern processing, transport and communication

Natural and anthropogenic changes in nutrient concentrations can affect phytoplankton in marine and freshwater environments. However, potential micronutrient limitation of phytoplankton productivity in fresh waters is often overlooked. To investigate the responses of lake phytoplankton to micronutrient enrichment, we conducted a study in two contrasting New Zealand lakes, and analysed data from the published international literature. We undertook nutrient enrichment bioassays of phytoplankton communities sampled from a mesotrophic reservoir and an eutrophic coastal lake to determine the relative occurrence of micronutrient (iron, boron, cobalt, copper, molybdenum) and macronutrient (nitrogen, phosphorus) limitation. In the mesotrophic reservoir, phytoplankton productivity was phosphorus limited. No evidence of micronutrient limitation was found in six bioassays in summer. In the eutrophic lake, tenfold enrichment of ambient micronutrient concentrations increased the primary productivity in four of 11 bioassays. During a cyanobacterial bloom in the eutrophic lake, experimental enrichment with boron, cobalt, copper or molybdenum increased primary productivity by 40 %. These four micronutrients are commonly applied as agricultural fertiliser in the lakes catchment. Nitrogen or phosphorus enrichment had no effect on phytoplankton productivity at this time. Micronutrient limitation has been reported in more than 40 lakes internationally, and our analysis of published data suggests that the prevalence of micronutrient limitation is unrelated to lake size or trophic state. As micronutrient enrichment can significantly increase phytoplankton productivity in a range of lakes types, the potential contribution of micronutrient enrichment to eutrophication should not be overlooked.

Geothermal features such as geysers, mud pools, sinter terraces, fumaroles, hot springs, and steaming ground are natural attractions often visited by tourists. Visitation rates for such areas in the Taupo Volcanic Zone of New Zealand are in the order of hundreds of thousands annually. These areas are also habitat for rare and specialized plant and microbial communities that live in the steam-heated soils of unusual chemical composition. We evaluated historical and current trampling impacts of tourists on the thermotolerant vegetation of the Waimangu and Waiotapu geothermal areas near Rotorua, and compared the results to experimental trampling at a third site (Taheke) not used by tourists. Historical tourism has removed vegetation and soil from around key features, and remaining subsoil is compacted into an impervious pavement on which vegetation recolonization is unlikely in the short term. Social tracks made by tourists were present at both tourist sites often leading them onto hotter soils than constructed tracks. Vegetation height and cover were lower on and adjacent to social tracks than further from them. Thermotolerant vegetation showed extremely low resistance to experimental trampling. This confirms and extends previous research that also shows that thallophytes and woody shrubs, life forms that dominate in thermotolerant vegetation, are vulnerable to trampling damage. Preservation of these vulnerable ecosystems must ensure that tourist traffic is confined to existing tracks or boardwalks, and active restoration of impacted sites may be warranted.

Recent comparative glasshouse experiments have failed to isolate growth or competitive performance that would explain invasiveness in Hieracium lepidulum in New Zealand. It has been noted in a number of studies that root infection by arbuscular mycorrhizal fungi (AMF) can alter growth and competitive performance in invasive species. We therefore tested whether H. lepidulum plants grown in experimental substrates (river sand and potting mix) were infected with AMF, and compared AMF infection rates of these plants with those of field collected and inoculated plants. AMF infection was quantified at 100× magnification using a modified grid line intersect method, following staining of root associated fungal structures using trypan blue. In addition, plant establishment, leaf cover, biomass, and root:shoot ratios of plants were compared to test whether presence of AMF in roots was associated with changes in plant performance. Very low AMF hyphal infection rates were found in H. lepidulum roots from plants grown on river sand and potting mix only, while c. 50% and 15% infection rate was observed in field collected and field soil inoculated plants, respectively. The presence of arum-type arbuscules confirms that observed non-septate hyphae were AMF. Plant establishment, cover, and biomass (unfertilised pots only) were greater in AMF infected plants, though this was possibly confounded with soil addition effects. Future studies must separate soil addition and AMF effects explicitly to determine whether growth performance differences among AMF and non-AMF H. lepidulum plants are directly related to the presence of the fungi.

Plant‐based defence mutualisms utilize plant morphology to reduce the performance of plant parasites through their natural enemies. Leaf domatia primarily occur in the axials of secondary veins and are often inhabited by microbivorous and predaceous mites which often increase plant growth rates and reproductive success by controlling plant pests. Our study investigated if domatia investment is limited by plant primary productivity. To our knowledge no studies have tested if foliar domatia are resource‐limited. We tested our hypothesis using the genus Coprosma (Rubiaceae), conducting correlative field surveys and manipulative experiments measuring domatia production in new leaves along temperature, nutrient and irradiance gradients. Field surveys indicated a strong positive association between leaf area, the number of secondary veins, and domatia per leaf. The number of potential sites for domatia is underutilised, with leaves on selected Coprosma species having on average 47 to 72% of the ‘maximum’ number of available sites where domatia could occur. Foliar carbon was positively associated with domatia investment. Coprosma plants held under elevated night‐time temperatures showed a 34–91% decrease in daily carbon gain, a 38% decrease in domatia per leaf mass, and a positive relationship between domatia investment and integrated daily carbon gain. Under irradiance and nutrient stress, our data indicated evidence of a positive relationship between domatia investment and foliar carbon. We found a significant negative association between relative investment in domatia produced and investment in new leaf biomass. Our findings suggest investment in foliar domatia is limited by primary productivity. We propose that domatia are discretionary goods and not intrinsic structures produced automatically on leaves that mites utilize. We suggest that plants have the ability to regulate domatia formation during leaf ontogeny, with investment controlled by resource availability and some intrinsic allocation mechanism to defence.