Characteristic scale of response for <i>Elater ferrugineus</i> using two models.

<p>i) Pooled density of trees within the groups <i>Quercus</i>, Noble 1 and Noble 2, and ii) density of <i>Quercus</i> only. The grey line indicates p<0.05, corresponding to Wald value 3.9.</p

Correlation between the densities of tree groups that explained the occurrence of <i>Elater ferrugineus</i>.

<p>Correlation between the densities of tree groups that explained the occurrence of <i>Elater ferrugineus</i>.</p

Trap locations in the county of Östergötland.

<p>(<b>a</b>) Trap location for systematically placed traps. Dots (•) represent occurrence of <i>E. ferrugineus</i> and crosses (×) represent non-occurrences. Thin lines delimit municipalities. (<b>b</b>) Trap locations of the two validation data sets. Filled circles (•) represent the strategic data set, sampled within the present study area and open circles (○) represent the Östergötland data set. Distributions of deciduous trees are marked in grey.</p

Maps of predicted occurrence of <i>Elater ferrugineus.</i>

<p>The maps show >25%, >50%, >75% and >90% probability of occurrence in the study area (<b>a,b,c,d</b>) and in the county of Östergötland (<b>e,f</b>) and the trap capture. Empty traps are presented by crosses (×) while occupied traps are marked with open circles (Ο) which size is proportional to the number of individuals caught. The first column (<b>a,c,e</b>) shows predictions based on models including the pooled density of trees within the groups <i>Quercus</i>, Noble 1 and Noble 2, while the second column (<b>b,d,f</b>) shows predictions based on models including the density of <i>Quercus</i> only. (<b>a,b</b>) shows trap captures in systematically placed traps, (<b>c,d</b>) the strategically sampled validation data and (<b>e,f</b>) the validation data set sampled in the entire Östergötland. In each map, the predictions are based on two models, one for each characteristic scales of response (blue tones represent a smaller scale: 433 m (pooled density of <i>Quercus</i>, Noble 1 and Noble 2) and 327 m (density of <i>Quercus</i> only), while orange tones represent prediction at larger scale: 4051 m (<i>Quercus</i>, Noble 1 and Noble 2) and 4658 m (<i>Quercus</i>).</p

Tree density required for 25%, 50% 75% and 90% probability of occurrence of <i>Elater ferrugineus</i>, for two candidate models and for two characteristic scales of response.

<p>Tree density required for 25%, 50% 75% and 90% probability of occurrence of <i>Elater ferrugineus</i>, for two candidate models and for two characteristic scales of response.</p

The relationships between occurrence of <i>Elater ferrugineus</i> and density of trees in different hollow classes.

<p>The relationships are expressed as Wald-values from 63 simple binomial GLMs. The explanatory variable ‘tree density’ is measured at 31 different spatial scales and includs trees from three different tree hollow classes: hollow trees ≥1 m dbh, hollow trees <1 m dbh and non-hollow trees. All models showed positive relationship between probability of occurrence and tree density. The grey line indicates p<0.05, corresponding to Wald value 3.9.</p

Categorization of trees in the study.

<p>Deciduous trees in the study area (49.4 km × 49.4 km) categorized according to the six tree groups and three tree hollow groups: ‘hollow’, which were then divided into two groups according to the diameter at breast height (dbh), and ‘non-hollow’ >0.70 m dbh.</p