Integrating landscape connectivity in broad-scale forest planning through a new graph-based habitat availability methodology: application to capercaillie (Tetrao urogallus) in Catalonia (NE Spain)

Abstract

The loss of connectivity of forest landscapes is seriously hindering dispersal of many forest-dwelling species, which may be critical for their viability and conservation. In this context, explicitly incorporating connectivity considerations is an important challenge in current forest planning and management, but as yet there is a lack of operative methods for appropriate decision making in this respect. We describe a new methodology based on graph structures and a habitat availability index (integral index of connectivity) that integrates forest attributes (like habitat quality) and network connectivity in a single measure. We apply this methodology to examine the connectivity of the highly fragmented habitat of capercaillie (Tetrao urogallus) in Catalonia (NE Spain), where the threatened status of this forest bird species calls for landscapelevel forest planning solutions. We analyse data on the distribution of capercaillie forest habitat at 1 km spatial resolution obtained from the recent Catalan Breeding Bird Atlas. We determine the functionally connected regions existing within its habitat distribution and identify the forest habitat areas that are more important for the maintenance of overall landscape connectivity for this species. Based on these results, we provide recommendations on certain critical public forests where management oriented to the conservation of capercaillie habitat is more necessary. These results highlight the potential and practical interest of the proposed methodology for successfully integrating landscape connectivity in broad scale forest planning.

Sustaining forest landscape connectivity under different land cover change scenarios

“…2-3) could significantly improve their effectiveness. Similar analyses were done for endangered forest bird species in Saura and Pascual-Hortal (2007) and Pascual-Hortal and Saura (2008), both indicating areas where some of the critical elements as connectivity providers for the Sustaining forest landscape connectivity focal species were not included in the protected network. In Jantke et al (2011) the suitability of the Natura 2000 network to cover endangered wetland vertebrate species was tested and they found out that five area-demanding vertebrates were not covered by the current reserve system.…”

“…PC is defined as the probability that two points randomly placed within the landscape fall into habitat areas that are reachable from each other (interconnected), given a set of n habitat patches and the links among them (Saura and Pascual-Hortal, 2007). The probability of direct dispersal (p ij ) between each pair of patches (required for the computation of the PC metric) can be estimated using a negative exponential function of the interpatch edge-to-edge Euclidean distance (Urban and Keitt, 2001;Pascual-Hortal and Saura, 2008) or of the effective distance (minimum cost) between patches (Rayfield et al, 2010;Gurrutxaga et al, 2011). The prioritisation and ranking of landscape elements by their contribution to overall connectivity can be calculated from the percentage of variation in PC (dPC) caused by the removal of each individual element (patch or link) from the landscape.…”

“…habitat area or quality) of the landscape elements being evaluated (Saura and Rubio, 2010). The habitat availability metrics have been applied in many studies (Neel, 2008;Pascual-Hortal and Saura, 2008;García-Feced et al, 2011;Pereira et al, 2011;Awade et al, 2012) (see a full list in http://www.conefor.org/ applications.html). More recently, the research attention has been focused on the connector fraction, both in network analytical (Bodin and Saura, 2010;Baranyi et al, 2011) and ecological application studies (Gurrutxaga et al, 2011;Saura et al, 2011;Rubio and Saura, 2012).…”

Effects of different matrix representations and connectivity measures on habitat network assessments

“…We assumed that the least-isolated patch is of highest importance for overall connectivity. We used Conefor Sensinode 2.6 (Saura and Pascual-Hortal 2007b;Pascual-Hortal and Saura 2007;Torne 2009, 2012) to evaluate the importance of habitat patches based on graph measures. To assess habitat patch (node) importance, Conefor Sensinode performs nodes removal operations (Urban and Keitt 2001).…”

Application of indicators network analysis to support local forest management plan development: a case study in Molise, Italy

“…Most of the changes in well-being occur at smaller spatial scale (Duraiappah 2011), but at the unit level the size is too small to consider all the aspects of the multiple role of forest, such as forest connectivity (Pascual-Hortal & Saura 2008, Saura et al 2011, or also watershed management (Smith et al 2003). Management of forests for a stable supply of amenities requires planning over broad spatial areas (Zhang et al 2011).…”