Signals of Climate Change in Butterfly Communities in a Mediterranean Protected Area

Abstract

The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998–2011/2012) and short-term (2011–2012) changes in the butterfly fauna of Dadia National Park (Greece) by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990–2012) in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a) species’ elevational distributions in Greece and (b) Community Temperature Index (calculated from the average temperature of species' geographical ranges in Europe, weighted by species' abundance per transect and year). Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011–2012) variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species’ resilience may have to be devised.

Who flies first? – habitat‐specific phenological shifts of butterflies and orthopterans in the light of climate change: a case study from the south‐eastMediterranean

“…Dadia NP is located in the east Mediterranean where extreme summer temperatures are anticipated in the future (Lelieveld et al, 2014). The rise of local temperature previously found (Zografou et al, 2014) might lead to multiple broods and prolonged flight periods (Haeler et al, 2014), but also it might intensify the extreme dry summer of the Mediterranean, causing ecological consequences to butterfly populations in Dadia NP by limiting adult nectaring and/or food availability (González-Estébanez et al, 2011). Trotta et al (2006) in their experiments showed that a short-lived invertebrate (Drosophila melanogaster Meigen) lived up to 29 days when raised at 31.2 ∘ C, whereas flies from the same population lived up to 247 days when reared at 12 ∘ C. In contrast, Maniola jurtina Linnaeus butterflies in Mediterranean, resulted in extremely prolonged life spans of females under continuous summer conditions (Haeler et al, 2014).…”

“…The climate is sub-Mediterranean, with a mean annual rainfall of 652.9 mm, a mean annual temperature of 14.3 ∘ C, presenting a minimum in January and a maximum in July-August, while the arid summer season extents from July to September (25 ∘ C, 210 mm) (Maris & Vasileiou, 2010). Along with the dry and hot summers that characterise Dadia NP, a significant increase of temperature by 0.95 ∘ C has been documented for a 22-year-period (1990-2012) (Zografou et al, 2014). The Dadia area was established as a nature reserve in 1980 mainly owing to its great variety of birds of prey, and since then it has been recognised for its high biodiversity value for other taxa (Korakis et al, 2006;Kati et al, 2007;Schindler et al, 2008), including invertebrates (Grill & Cleary, 2003;Kati et al, 2004Kati et al, , 2007Argyropoulou et al, 2005;Korakis et al, 2006;Schindler et al, 2013).…”

“…We considered two butterfly datasets from 1998 (Grill & Cleary, 2003) and 2011 (Zografou et al, 2014), which followed exactly the same sampling strategy (standard line transects; Pollard & Yates, 1993). Species diversity and abundance were recorded along 21 transects of a 200 m length and 5 m width, covering three major habitat types (forests, grasslands, and agriculture fields).…”

“…Apart from the warmer microclimate, the longer duration of a flight period in agriculture fields could be attributed to the extended availability of nectar resources; agricultural areas in Dadia NP have a traditional character with natural hedges and tree lines providing shade and flowering plants at field margins. At the same time, these areas provide cooler patches as a result of the irrigation system, prolonging the 'green season' and thus nectar availability until late summer (Zografou et al, 2014). Nectar constitutes the basic diet for temperate-zone butterflies (Wheeler, 1996), supplies them with the required energy for flight (Stefanescu & Traveset, 2009), and increases longevity through carbohydrate intake (Murphy et al, 1983).…”

Performance of methods to select landscape metrics for modelling species richness

“…The area is dominated by extensive pine and oak forest, but also contains a variety of other habitats such as pastures, arable land, torrents and stony hills. Dadia NP is a local biodiversity hotspot and has a successful history of monitoring, research and management for the conservation of biodiversity (Catsadorakis and Källander, 2010;Kati et al, 2004a,b;Schindler, 2010;Schindler et al, 2011;Zografou et al, 2014).…”