Monitoring Pollinators: Case studies from Australia and New Zealand

Abstract

Pollination is an essential ecosystem service - yet in Australia, New Guinea, New Zealand and on the Oceanic Islands - we know very little about our pollinators. Monitoring is a key step here as it provides data on longer term trends and the information we lack on the distribution and ecology of pollinators and their ecosystem service-role. In addition the relative contributions of introduced and native pollinators in natural and agro-ecosystems is poorly understood from an economic perspective. To establish baselines for monitoring trends in pollinator services in Oceania, we have adopted diverse methods depending on the type of plant-pollinator interaction and the purpose of the investigation. Monitoring is undertaken for a variety of reasons, e.g. to detect change in pollinator communities in fragmented landscapes, to gauge the impact of exotic pollinators on native and exotic plant species, or to determine the contribution of alternative native pollinators in crops. Pollination systems in Oceania depend on the pollinating fauna available which is of very low diversity on most of the small remote islands (e.g., New Zealand) but higher in diversity in large continental sized islands (e.g., Australia). In island systems, exotic naturalized insects and plants are significant components of many habitats. Exotics may have positive or negative effects on native pollination systems (Newstrom and Robertson 2005). In some cases, it is clear that only exotic pollinators (e.g., bumblebees or honeybees) are capable of pollinating exotic plants. This type of interaction is called an "invasive mutualism" because without the exotic pollinator the exotic plant would not set seed and spread (e.g., broom, Simpson et al. 2005). In other cases, exotic pollinators may benefit native flora because they replace lost pollinators (e.g. birds on the mainland of New Zealand). Similarly, exotic plants rich in floral resources may benefit native pollinator populations but this could lead to abandonment of native plants leaving them bereft of pollinators.