Benefits of Remote Sensing Data for Biodiversity Monitoring Birds, Ants and their Role as Predators
Abstract
Biodiversity describes the variability of all living organisms and comprises the variability of ecosystems, of species, and within species (genetic diversity). One of the most diverse, important, and threatened biodiversity hotspots of the world are tropical mountain rainforests. Especially the Andean mountain rainforests are known for high numbers of endemic species such as trees, moths, and birds. Land use intensifications often threaten mountain ecosystems through a loss of biodiversity – e.g. extinction of certain species. As every species plays a specific role within an ecosystem a loss of diversity can lead to the degradation of important ecological functions. One important ecological function is herbivory of insects on seedlings, which influences the ability for forest regeneration. For instance, a compositional change of insects and/or their predators can strongly alter forest regeneration. Simultaneously, herbivores depend on the diversity of occurring plants and are regulated by their predators – e.g. insectivorous birds, ants, and wasps. High numbers of insectivorous predators have cascading effects on forest regeneration: Decreasing numbers of herbivores reduce herbivory leading to enhanced plant seedling survival. A continuous monitoring of all aspects of biodiversity is there fore important. This means to monitor different measures of biodiversity and not only selected important or attractive species (often called flagship species). Instead, integrative indicator systems are urgently needed that comprise species as well as functional diversity measures. A continuous monitoring of herbivory and predation can provide important insights into the status of forest ecosystems. Nevertheless, the quantification of those functions is time consuming and cost intensive, especially for large areas. A simple indicator system that can be applied over large scales is therefore urgently needed for conservation planning and the development of management strategies. Recent improvements of remote sensing technologies offer possibilities to develop indicator systems at a landscape scale with high resolutions. Remote sensing data – such as aerial pictures – can be used to predict certain aspects of biodiversity such as species richness. The development of indicator systems for ecosystem functions – such as herbivory, predation, or seed dispersal – would allow a continuous and convenient monitoring of the status of threatened ecosystems and the biodiversity there in.
