Research trends on integrative landscape assessment using indicators - A systematic review

Indicators are increasingly needed in landscape assessment. Over recent years, a wide range of methods and assessment frameworks were developed to describe and evaluate landscape. However, landscape study is supported by several disciplines with different research targets and goals. Hence, it is not clear to what extent academic research shows interest in holistic, multidisciplinary, and integrative approaches combining a broad spectrum of indicators. To assess this, the ability to compare research outcomes through the indicators they have used provides common ground, enabling a comprehensive analysis across several fields and topic areas. Which six categories of indicators are commonly considered and combined (e.g., ecological, historical-cultural, socioeconomic, land use, environmental and perceptual), along with the leading research trends and gaps of integrative assessments is of particular interest to landscape assessment research. Relevant records were selected following a PRISMA protocol, where indicators used in the literature were identified and organised according to the six category reference framework. Only papers with at least three categories were further analysed according to the spatial and temporal context, the integration of indicators, and the primary assessment goals. Finally, a random forest model is explored to predict which variables correlate the most with integrative studies. Main research trends and gaps are also presented and discussed. Results revealed that, although the number of integrative studies has increased through time, only 14 of the 239 retrieved records (5%) consider all six categories of indicators. The most combined indicators are ecological and land use, also registering the highest increasing trend. Historical-cultural and perceptual indicators were the least mentioned (6 and 7%, respectively). Records related to planning, management and policy monitoring goals are the most successful for stimulating integration. Studies target mainly heterogeneous regions (31%), followed by urban and agricultural landscapes (16% and 14%). In conclusion, the main integration gaps pertain to the socioeconomic, perceptual, and historical categories. This review offers an innovative approach to compare indicators used by different assessment frameworks, disciplines, and topic areas. The presence of indicators from different categories enabled the operationalisation of a systematic, formal, and applicable evaluation system to a large number of articles. This simplification offers one of many possible perspectives on a very complex issue, difficult to measure and evaluate.