Vol.:(0123456789) 1 3 J Insect Conserv (2017) 21:873–883 DOI 10.1007/s10841-017-0026-8 ORIGINAL PAPER Water availability drives habitat quality for the butterfy Plebejus argus in a Mediterranean sand dune landscape Pilar Fernández 1  · David Gutiérrez 2  · Diego Jordano 1  · Juan Fernández Haeger 1   Received: 26 June 2017 / Accepted: 7 October 2017 / Published online: 16 October 2017 © Springer International Publishing AG 2017 (mutualistic ants and nectar sources). As a result, we found a high spatial congruence in habitat quality between males and females, and a moderate congruence between adults and eggs. Keywords Lasius niger · Lycaenidae · Nectar sources · Resource-based habitat · Water table depth Introduction The occurrence of species is afected by the area, isola- tion and quality of habitat patches (Thomas et al. 2001). In continuous landscapes, in which the spatial arrangement of habitat (area and isolation) has little efect on the distribu- tion of a given species, the relative role of habitat quality is expected to be more important (Mortelliti et al. 2010). Vegetation or land cover types are frequently used as sur- rogates of habitat availability, but the appropriate defni- tion of habitat quality requires more detailed information on the resources and conditions that are necessary for the maintenance of the species (Dennis et al. 2003; Mortelliti et al. 2010). This idea underlies the ‘resource-based habitat approach’ (Dennis et al. 2003), which has been suggested a much better perspective for efcient conservation of species (Dennis et al. 2006). Key processes involved in survival and reproduction of an individual should be the most important clues in habitat use (Sharp et al. 1974; Stefanescu and Traveset 2009). These clues include diferent abiotic factors like climate, geology, nutrients, shelter but also biotic interactions (Kubo et al. 2009; Berg et al. 2013; Lawson et al. 2014; Ochoa-Hueso et al. 2014; Suggitt et al. 2015). In the case of arthropods, their life cycle comprises several clearly diferentiated stages that may depend on diferent resources and conditions for Abstract For terrestrial species, habitat is frequently defned as physical patches of a certain land cover type in a matrix of non-habitat. However, the appropriate defnition of habitat quality requires more detailed information on the resources and conditions that are necessary for the mainte- nance of the species (‘resource-based habitat approach’). In arthropods, their life cycle comprises several clearly dif- ferentiated stages that may depend on diferent resources and conditions for successful development; in turn, males and females may have diferent habitat requirements due to their diferent behaviours. Here we examine the habitat quality for males, females and eggs of the butterfy Plebe- jus argus in a continuous sand dune landscape in southern Spain. For both sexes, abundance was related to host plant density (negatively) and distance to heathland vegetation (a surrogate for higher water availability; negatively for males and hump-shaped for females); and, for males only, posi- tively with fower presence. Egg abundance was positively related to mutualistic ant frequency and fower presence, and negatively to distance to heathland. Hence, female and male adults and eggs of P. argus partly difered in their depend- ence on resources and conditions, although distance to wet- ter areas of heathland was the common variable for all mod- els. This suggests that soil humidity is the key variable for P. argus habitat quality, probably through both direct efects on individuals and indirect efects on interacting species * Pilar Fernández bv2ferop@uco.es 1 Departamento de Botánica, Ecología y Fisiología Vegetal, Universidad de Córdoba, Campus de Rabanales. Edifcio C-4, 14071 Córdoba, Spain 2 Área de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain