The biodiversity of forests cannot be measured nor directly monitored. Indicators, based on scientific methods, are a way to better understand the diversity of natural landscapes. They are furthermore a source for policy consultation and other relevant stakeholders to set goals. The Austrian Research Centre for Forests (BFW) has the mandate to develop indicators for measuring biological diversity in forest ecosystems.
Following an initiative of the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW), BFW has set important steps to implement suitable indicators describing the conditions of biodiversity in our forests. Two aspects are important to understand – firstly biodiversity in forests cannot be determined entirely. The status and development can be measured to a certain degree, taking genes, species and the full multeity of ecosystems into account. Secondly target values are weighted in the Austrian Forest Biodiversity Index (AFBI). It is an innovative approach to evaluate the current situation and to understand the efficiency of implemented measures.
Biodiversity in an international and national context
The forest biodiversity index is a measure complying with international reporting commitments. The convention on biological diversity agrees on the definition of biodiversity as “the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems”. Following the UN Earth summit in Rio de Janeiro (1992) Austria developed a biodiversity strategy in 1998. The national Biodiversity Strategy 2020+ includes the targets of EU strategies and regulations.
Biodiversity in forests
The data for the AFBI is mainly based on outcomes of the national forest inventory. The biological diversity of forests includes all plants, animals and micro-organisms inhabiting the wooded land and all associated genetic diversity. From a biodiversity point of view the optimum is reached when anthropogenic influence is negligible, the composition of species equates to the “potential natural vegetation”, a sufficient amount of deadwood and veteran trees exist and natural vegetation occurs without too much influence by game or livestock. A value of 100 (best condition) can be scored in managed forests just theoretically.
Indicators of the AFBI
The indicators of the Forest Biodiversity Index are selected based on the criteria reliability, validity and objectivity. It is furthermore important to utilize already existing data and to choose definable target values. Three main indicator pools were identified – the status indicators, pressure indicators and response indicators. The status indicators include tree species composition, the amount of neophytic and dead trees as well as forest fragmentation. The pressure on ecosystems is evaluated based on browsing activities in the forests. The response indicators highlight the genetic reserves, the amount of seed stands and natural forest reserves.
The AFBI is a proposal by BFW to describe the approximately biodiversity of Austrian forests. It is an aggregated approach. For the national territory an AFB Index of ca 60 points was calculated. The value can be considered as (very) high. Regions of higher values are the “Randalpen” and “Innenalpen”, the “Waldviertel” region and “Mühlviertel” have a compared lower index. An assessment over a longer period of almost 20 years was possible due to the sufficient availability of data. The outcomes can be integrated in concepts to improve the conditions of forest biodiversity and offer a scientific basis for political decision making.