The reproductive biology of 16 native shrub species was studied in 34 populations to identify breeding systems, pollen limitation, local abundance, and population age structures. Seven of the study species are hermaphroditic, seven dioecious, and two gynodioecious. one of the 18 hermaphrodite populations (Alseuosmia macrophylla at Mamaku Plateau) had high levels of self-incompatibility and pollen limitation and mutualism failure was evident. in the gender-dimorphic taxa, two populations (Coprosma spathulata from Hakarimata and Cyathodes juniperina from Pukemokemoke) had high levels of pollen limitation and insect-pollinated species consistently ranked higher in a vulnerability assessment compared with wind-pollinated species. There was no significant relationship between natural fruit set and the distance to the nearest conspecific pollen in any of the study populations. Seedling recruitment was variable but evident in 32 of the 34 study populations and appeared to be related to availability of suitable habitat. The species we studied occur mostly on forest edges where they rely on disturbed soil and high light conditions for establishment, and edges may be important for successful reproduction of some native plants, especially shrubs. We have demonstrated that plants with self-incompatibility mechanisms and pollinator specialisation are at greater risk from pollen limitation and mutualism failure than self-compatible or generalist species.

We assessed the degree of pollen and fruit-dispersal limitation in the endemic gynodioecious New Zealand tree fuchsia Fuchsia excorticata over several seasons and at 17 sites throughout New Zealand. The flowers were visited mainly by two endemic honeyeaters (bellbirds and tui), and in some cases very frequently by silvereyes, which also occasionally rob nectar from flowers. We confirmed that hermaphrodites account for more than half the plants in all populations, are fully self-compatible, and can autonomously self in the absence of pollinators (especially in plants with smaller herkogamy). Fruit production in hermaphrodites and (particularly) females was frequently pollen-limited (mean Pollen Limitation Indices of 0.17 and 0.40, respectively), and was correlated with visual assessments of pollen loads on the stigma, a useful index of pollinator service. A comparison of the proportion of ripe or overripe fruit on branches exposed to birds versus branches enclosed in wire cages showed that uncaged fruit on Kapiti Island is removed almost as soon as it is ripe but on the mainland it persists for much longer. The proportion of ripe or overripe compared to green fruit is therefore an approximate index of dispersal service. Both indices may be useful to managers concerned with measuring the level of mutualism service provided by native birds.

The results suggest that for these populations, over half of the seeds produced are genetically doomed. This reduction in the fitness of progeny due to reduced pollinator service is probably important to population dynamics of other New Zealand species. More broadly, the results suggest that measures of seed production or seedling densities may be a gross overestimate of the effective offspring production. This could lead to cryptic recruitment failure, i.e. a decline in successful reproduction despite high progeny production. Given the global extent of pollinator declines, cryptic recruitment failure may be widespread.

1. Globally, invasive non-native plants are an increasing threat to indigenous biodiversity and ecosystems, but management can be compromised by poor efficacy of control methods, harmful non-target effects or secondary invasions by other non-native plant species. 2. A 5-year field trial compared two stakeholder-selected control methods for heather, a European plant invading native ecosystems in and adjoining Tongariro National Park in New Zealand. The control methods were a selective herbicide (Pasture Kleen ® ; 2,4-D ester) and biocontrol with an introduced beetle Lochmaea suturalis (Coleoptera: Chrysomelidae). 3. Biocontrol reduced mean heather cover by 97%, slightly more than herbicide at 87%, compared with a 20% increase in heather under no management. 4. Cover of native dicots, the most species-rich plant group, increased following biocontrol. In contrast, herbicide application had major non-target effects on native dicots, reducing their percentage cover and species richness. Native monocot cover and species richness increased following both herbicide and biocontrol treatments. 5. A similar eightfold increase in non-native monocots occurred following both biocontrol and herbicide treatments. Overall, secondary invasion was greatest with biocontrol because non-native dicot cover also increased, whereas herbicide almost eliminated non-native dicots. 6. Synthesis and applications. Biocontrol and herbicide treatments both controlled heather but herbicide application was associated with severe non-target impacts on native dicots. Benefits to the native flora were consequently greatest in the biocontrol treatment, despite greater secondary invasion. Control strategies for management of widespread non-native plants to optimize ecosystem outcomes should include more consideration of biocontrol.

The ecology of Alseuosmia quercifolia, a small endemic shrub, was investigated, focussing on its habitat requirements, population dynamics, phenology and reproductive biology, and conservation status. This species occurs most commonly in lowland native forests of the Waikato region of the North Island (north of latitude 38°05'S), but is also found in scattered populations to North Cape. In the Waikato region it typically occupies shady, welldrained, south or south-east facing lower slopes of hills and ranges at altitudes below 400 m. Population structures show considerable variation amongst seven study sites in the Waikato region, with disjunct size classes a reflection of the presence and abundance of introduced browsing mammals. It is a relatively short-lived (less than 50 years), slow-growing species with a fleshy fruit adapted to bird dispersal, but seed dispersal now appears to be primarily by gravity. Flowering occurs early in spring and is synchronous at both individual and population levels, occurring over a 5-week period, with peak flowering during the second and third weeks. While all populations set seed, reproductive output can be negatively affected by persistent browse and by rain during peak flowering. This species is vulnerable because it is highly palatable to introduced mammals and all plants in a population are within browse height. It has relatively narrow habitat specificity, localised distribution, and limited potential to extend its range. We suggest it fulfils the requirements of the category "declining", using the most recent classification of threatened and uncommon plants of New Zealand.