Thematic resolution matters: Indicators of landscape pattern for European agro-ecosystems

Selecting meaningful metrics to describe landscapes is difficult due to our limited understanding of the links between landscape pattern and ecological process, the numerous indices available and the interaction between the spatial characteristics of the system and metric behaviour. We used an exploratory approach (factor and cluster analysis) for the selection of small sets of landscape descriptors. Twenty-five agricultural landscapes located across temperate Europe were classified using coarse (two and three classes), intermediate (14 classes) and fine (47 classes) scales of thematic resolution. We used statistical analyses to identify which landscape metrics were most useful for distinguishing between different landscapes at each of these scales of thematic resolution. We examined which aspects of spatial pattern were described by the selected metrics and compared our selection with metrics chosen in previous studies. Many of our landscape descriptors were common to earlier investigations but we found that the suitability of the indicators were dependent upon thematic resolution. At coarse thematic scales metrics describing the grain and area occupied by the largest patch (dominance metrics) were suitable to distinguish between landscapes, whereas shape, configuration and diversity indices were more useful at finer scales. At intermediate scales metrics that represent all of these components of landscape pattern were appropriate as landscape descriptors. We anticipate that these results will enable a more informed selection of metrics based on an improved knowledge of the effects of thematic resolution.