Results of Redundancy analyses analyzing butterfly species composition.

<p>Summary of single-term ordinations of predictors of interest (<i>Forest encroachment</i> and <i>Canopy)</i> and potential covariates (site characteristics and visit circumstances) as well as partial RDA ordinations assessing the effect of predictors of interest on butterfly species community composition (BSC) after controlling for site characteristics and visit circumstances (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#sec002" target="_blank">Methods</a> for details).</p

Life History Traits Reflect Changes in Mediterranean Butterfly Communities Due to Forest Encroachment

<div><p>The biodiversity of the Southern Balkans, part of the Mediterranean global biodiversity hot-spot, is threatened by land use intensification and abandonment, the latter causing forest encroachment of formerly open habitats. We investigated the impact of forest encroachment on butterfly species richness, community species composition and the representation of life history traits by repeated seasonal visits of 150 one-hectare sites in five separate regions in three countries—Greece, Bulgaria, and the Republic of Macedonia (FYROM—the Former Yugoslav Republic of Macedonia)— 10 replicates for each habitat type of grasslands, open formations and scrub forest within each region. Grasslands and open formations sites hosted in average more species and more red-listed species than scrub forest, while no pattern was found for numbers of Mediterranean species. As shown by ordination analyses, each of the three habitat types hosted distinct butterfly communities, with Mediterranean species inclining either towards grasslands or open formations. Analysing the representation of life history traits revealed that successional development from grasslands and open formations towards scrub forest shifts the community composition towards species overwintering in earlier stages, having fewer generations per year, and inhabiting large European or Eurosiberian (e.g. northern) ranges; it decreases the representation of Mediterranean endemics. The loss of grasslands and semi-open formations due to forest encroachment thus threatens exactly the species that should be the focus of conservation attention in the Mediterranean region, and innovative conservation actions to prevent ongoing forest encroachment are badly needed.</p></div

Impact of <i>Forest encroachment</i> and <i>Canopy</i> on butterfly species richness (A-B) and Red-listed species (C-D) recorded during 2012–2013 from 150 sites in the Southern Balkans.

<p>The box plots show values of species richness (A) and Red-listed species (C) predicted by the generalised linear model (glm) with <i>Forest Encroachment</i> treated as 3-level factors, no covariates included. The lines in (B–D) show glm predicted values with <i>Canopy</i> covers treated as linear predictor after inclusion of covariates for Species Richness (B) and without covariates for Red-listed species (D). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.t001" target="_blank">Table 1</a> for details.</p

Ordination diagrams showing life-history traits interpretation of analyses of the effects of <i>Forest encroachment</i> and <i>Canopy</i> on butterfly community composition.

<p>Partial redundancy analysis, computed after including covariates (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.t002" target="_blank">Table 2</a> for formulation of covariate model) and removing the effects of phylogeny. The arrows in panels (A–D) stand for horizontal (“<i>Scrub forest</i>”) and vertical (“<i>Open formations</i>”) ordination axes in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.g003" target="_blank">Fig 3(A)</a>, whereas panels (E–H) refer to ordination diagrams in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.g003" target="_blank">Fig 3(B)</a>. Statistical tests in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.t003" target="_blank">Table 3</a>.</p

Results of life history traits analysis.

<p>Traits-based interpretation of partial RDA ordinations of Southern Balkans butterfly community species composition (BSC) that assessed the response to <i>Forest encroachment</i> and <i>Canopy</i> models including significant covariates and controlled for phylogeny.</p

A map of the Southern Balkans showing the five study regions where impacts of Forest encroachment on butterflies were studied.

<p>R1 –foothills of Paramythia Mts, NW Greece (Epirus province); R2 –foothills of Taygetos Mts., S Greece (Lakonia); R3 –southern foothills of Giona Mts, Greece (Sterea Ellada); R4 –Macedonia, Prilep environs; R5 –SE Bulgaria (Kardzhali environs). Average aerial distance among regions was 220 km (range 143–320 km).</p

Ordination diagrams (partial redundancy analysis), showing the effect of (A) <i>Forest encroachment</i>, and (B) <i>Canopy</i> on butterfly species community composition.

<p>Both diagrams refer to analyses that statistically controlled for effects of covariates, and removed the effects of phylogeny (covariate model as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.t002" target="_blank">Table 2</a>). See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152026#pone.0152026.t002" target="_blank">Table 2</a> for results of statistical tests. Species with Mediterranean ranges written in bold, Red-listed species in CAPITALS.</p