Forest Ecology and Management 262 (2011) 1061–1066 Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco Selective logging in public pine forests of the central Iberian Peninsula: Effects of the recovery process on ant assemblages ⇑ Crisanto Gómez , Sílvia Abril Department of Environmental Sciences, University of Girona, Montilivi Campus s/n, 17071 Girona, Spain article info abstract Article history: Pine forests on the northern plateau of the Iberian Peninsula have a long history of use, exploitation, and Received 5 April 2011 management. Current management practices consist of selective logging with relatively short periods of Received in revised form 25 May 2011 time between logging events. The main objective of this study is to detect changes in ant assemblages in Accepted 27 May 2011 the short time periods between selective logging activities. Ants were sampled at 44 sites considering three grouping categories of time periods after the last timber extraction: short (<4 years), medium (4–8 years) and long (>8 years). After selective logging the number of ant species increases as the forest recovers. A look Keywords: at the differences between the assemblages when the analysis shifts from the species-specific level to func- Ants tional groups showed differences between the short and long categories. This indicates that in certain cir- Formicidae Ant assemblages cumstances the functional groups may be more informative of the functional restructuring of the ant Forest management assemblages in a disturbed habitat. Ant species from three functional groups display significant indicative Functional groups values (Opportunist, Hot Climate Specialists and Subordinate Camponotini) in the medium- and long-time- Pine forests after-logging categories: Messor capitatus (HCS) for medium-time category sites; and Aphaenogaster iberica (Op), Camponotus cruentatus (SC) and, Cataglyphis velox (HCS) for long-time category sites. No indicator spe- cies were found for the early stages of recovery. This information may also be of interest to managers because it reduces the number of data elements of the recovery status of these forests, and can be translated into monitoring protocols. The continued exploitation of these forests leads to an ant fauna that reflects this change. The results show that ant assemblages need at least 8 years to recover since only after that much time there is an emergence of Subordinate Camponotinae, a behaviorally dominant and low stress-tolerant functional group. This selective logging maintains the relative diversity and structure of ant assemblages. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction Given the general poverty of the soils of these pine forests, the underwood is very poor in woody shrubs, presenting a layer of dis- Pine forests (Pinus pinea L. and Pinus pinaster Ait.) on the northern continuous herbaceous mat composed mainly of various species of plateau of the Iberian Peninsula, located in a region known as Tierra xeric grasses. Forest management in the study area is characterized de Pinares (Pine Land) have a long history of use, exploitation and by a relatively low harvest intensity that permits a greater average management (Aránzazu et al., 1997). Information exists about the density of pines during the production cycle (213 pines haÀ1). This use and exploitation of pine forests (logging, harvesting pine nuts, management is designed to encourage more timber production, and resin collection) in human settlements of the first Iron Age in although it does not prevent the extraction of pine nuts. The man- the area of study. These species do not sprout, so they are very sen- agement of similar forests to produce pine nuts or combined wood sitive to human disturbance. We understand that there is a docu- and pine nuts needs less pine density (100–175 pines haÀ1) or, what mentary record of the region’s management and custody since the is the same, higher intensities of logging. An increase in canopy eleventh century. The pine forests under study are public use forests openness and a reduction in vegetation structure and understory in the province of Valladolid (Castile and León). They have been pre- plant richness can cause great changes to ant communities (Uhl served and managed as public use forests since their listing in 1859. and Vieira, 1989). However, taking into account both aspects, mainly This catalog of forests should be seen as a guarantee that their genet- herbaceous vegetation and relatively low intensity logging, the im- ic structure results from pristine formations, which have been al- pact of logging on the overall structure of the habitat is relatively tered by the story of the human-Mediterranean forest relationship light; except, of course, the partial disappearance of the tree layer. (Aránzazu et al., 1997). Ants are one of the terrestrial invertebrate groups used as bioin- dicators. They have been included in monitoring programs associ- ⇑ Corresponding author. ated with human activities around the world (Andersen et al., E-mail addresses: [email protected] (C. Gómez), [email protected] 2002; Bestelmeyer and Wiens, 1996; Gunawardene et al., 2010; (S. Abril). Majer, 1983; Nakamura et al., 2007; Read and Andersen, 2000; 0378-1127/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.foreco.2011.05.043 1062 C. Gómez, S. Abril / Forest Ecology and Management 262 (2011) 1061–1066 Ottonetti et al., 2006; Stephens and Wagner, 2006). In those pro- The distances between the five pine forests ranged between 1 grams ants have been used to monitor the effects of forest manage- and 5 km. ment practices such as selective logging and clearing, subsequent Ant species were assigned to functional groups according to their habitat recovery processes, or the subsequent land use of forest responses to environmental stress and disturbance, in line with pre- clearings (Gunawardene et al., 2010; Maeto and Sato, 2004; Nakam- vious studies of ants as bioindicators (Andersen, 1995, 1997; Read ura et al., 2007; Palladini et al., 2007; Stephens and Wagner, 2006). and Andersen, 2000; Gómez et al., 2003; Stephens and Wagner, Ants are an important component of the animal biomass and act 2006) and the information about ant functional group assignment as relevant ecosystem engineers (Folgarait, 1998). They have an compiled by Brown (2000). The functional groups considered are important influence on soils (Lobry de Bruyn, 1999), vegetation Dominant Dolichoderinae (DD), Subordinate Camponotini (SC), (herbivores, seed predators, seed dispersers) (Buckley, 198 2), and Hot Climate Specialist (HC), Cold-climate Specialist (CC), Cryptic other faunal groups. Ants are relatively sedentary and responsive Species (Cr), Opportunists (Op), Specialist Predators (SP), and Gener- to changes occurring at relatively small scales in space and time, alized Myrmicinae (GM) (Andersen, 1995, 1997). The Formica spe- most of which are easily sampled and observed, and the ecology of cies were assigned to the Opportunist group (all of them belong to the group as a whole is comparatively well understood (Brown, the fusca group) and the Tapinoma species were assigned to the 2000; Hölldobler and Wilson, 1990; Lach et al., 2010). These features Dominant Dolichoderinae group (Gómez et al., 2003; Castracani have made them focal animals in studies of the effects of all kinds of et al., 2010). ecological disturbances on terrestrial ecosystems. The use of ants and functional group approaches in studies of 2.2. Sampling Mediterranean ecosystems is slowly increasing (Gómez et al., 2003; Ottonetti et al., 2006; Castracani and Mori, 2006; Castracani Sampling was conducted in the warmer season, during June and et al., 2010) and the interesting results add substantial validity to July 2009, when ant activity is high in Mediterranean ecosystems their use as bioindicators. Also, we have relatively good knowledge (Cros et al., 1997). At each site, three sample points were randomly of ant species diversity and taxonomy for the Iberian and the Ital- established and separated by at least 25 m. Ants were sampled at ian peninsulas. Although studies of this type have been few to date, each sample point using two methods: pitfall trapping (3 traps open the increasing knowledge of Mediterranean ants makes them suit- for 48 h; 2.5 cm diameter; partly filled with ethylene glycol as a pre- able as an animal group of reference. servative, and 5 m apart, forming a triangle) and hand collecting (1 The main objective of this study is to detect any changes that person  30 min) around the trap triangle. A total of 396 traps were occur in ant assemblages in the short periods of time between placed in the pine forests (3 traps  3 sample points  44 sites) and selective logging activities in these pine forests. We wonder if 66 h of hand collecting (0.5 h  3 sample points  44 sites) took the ants can inform us of changes that have occurred after logging place. All ants were sorted by species and identified. The presence and during the forest recovery process. Our hypothesis is that this of each ant species in the trapping and hand collecting samples selective logging does not produce dramatic changes and helps to was recorded. All specimens were preserved and deposited in the maintain the relative diversity and structure of ant assemblages. laboratory of the PECAT Research Group, Department of Environ- mental Sciences, University of Girona. 2. Methods 2.3. Data analysis 2.1. Study site For each sample point, the data from the three pitfall traps and The study was carried out in Tierra de Pinares (Pine Land) situ- the hand collecting were combined. Ant species richness (number ated on the northern plateau of the Iberian Peninsula (Castilian of species) was compared for time categories using a one-way AN- Plateau, Castile and León, Central Spain) (Fig. 1). The pine forests OVA (SPSS 15.0).