Research

The aim of the project is to survey hoverflies, together with bees the most important pollinators worldwide, nationwide. This will be the standardised monitoring data for these important headline indicators for the first time in Austria. In addition, the flowering plants visited by the hoverflies are to be plants visited by hoverflies in order to gain knowledge about the pollen and nectar sources of hoverflies. Data on the occurrence and distribution of highly endangered hoverfly species in Europe will also be collected. Overall, the project fills a gap in Austria's biodiversity monitoring, also collects data on species that are highly endangered throughout Europe, and thus represents an important contribution to achieving the goals set out in the national biodiversity strategy. It establishes the headline indicator hoverfly in Austrian biodiversity monitoring.

The von Bertalanffy equation was developed in the 1940s and has since been the almost universal biologically motivated model to describe the ontogenetic growth of different species; it is characterized by the metabolic exponents a = 2/3, b = 1. West et al. (1997, 2001) suggested another pair of metabolic exponents (a = 2/3, b = 1) and provided biological reasoning for this choice. This project proposes biological reasoning for yet two other exponent pairs based on the ideas of Bertalanffy and West about metabolism and on a model of Parks (1982) about the dependency of growth on food intake.

In recent years, the use of terrestrial laser scanners (TLS) and airborne laser scanning (ALS) to characterize forests has made considerable progress and can be used both to record individual trees and thus biomass and carbon stocks and to monitor changes (growth, turnover). In evergreen tropical forests, such evaluations face the challenge that it is not possible to measure in a leafless state, which limits the view of trunks and branches and thus makes it difficult to calculate trunk sizes. In 2024, LIDAR surveys were carried out in La Gamba, Costa Rica, in primary, secondary forests and reforestation areas with planted trees using modern TLS and ALS systems. These data are to be analyzed as part of the project. First, individual TLS scans must be linked and the trees segmented, then these results will be checked with direct measurements of the trees on site and, as far as possible, the allometric model used for biomass calculation will be improved.