Abstract. 1. The habitat components determining the structure of bee communities are well known when considering foraging resources; however, there is little data with respect to the role of nesting resources.2. As a model system this study uses 21 diverse bee communities in a Mediterranean landscape comprising a variety of habitats regenerating after fire. The findings clearly demonstrate that a variety of nesting substrates and nest building materials have key roles in organising the composition of bee communities.3. The availability of bare ground and potential nesting cavities were the two primary factors influencing the structure of the entire bee community, the composition of guilds, and also the relative abundance of the dominant species. Other nesting resources shown to be important include availability of steep and sloping ground, abundance of plant species providing pithy stems, and the occurrence of pre-existing burrows.4. Nesting resource availability and guild structure varied markedly across habitats in different stages of post-fire regeneration; however, in all cases, nest sites and nesting resources were important determinants of bee community structure.Key words. Bees, community organisation, Mediterranean, nesting guilds, resource availability. IntroductionOrganisation of bee communities is closely related to the floral communities they forage upon, with several key characters having been identified, including floral diversity (e.g. Tepedino & Stanton, 1981;Gathmann et al., 1994), floral abundance (e.g. Banaszak, 1996), and availability of pollen and nectar resources (Petanidou & Vokou, 1990). However, few studies have attempted to quantify the combined effect of these structuring agents (but see Potts et al., 2003a).In turn, some drivers have been identified that impact directly upon bee communities, while others act indirectly through modification of floral communities or other habitat characteristics. These drivers include changing land use practices such as agricultural intensification (Banaszak, 1995), habitat fragmentation (Jennersten, 1988) and habitat isolation (Steffan-Dewenter & Tscharntke, 1999), grazing (Potts et al., 2003a), and agrochemical use (O'Toole, 1993). Other important drivers have also been recently identified: fire (Potts et al., 2003b); disease (Watanabe, 1994) and parasite spread (Schmid-Hempel & Durrer, 1991); climate change (Price & Waser, 1998); introduction of non-native plants (Brown & Mitchell, 2001;Chittka & Schu¨rkens, 2001); and competition with managed pollinators (Butz-Huryn, 1997;Steffan-Dewenter & Tscharntke, 2000).While the forage rewards provided by floral communities are generally accepted as the primary determinants of pollinator community structure, there is an increasing body of evidence suggesting that nest sites and nesting resources may

Globally, plant-pollinator communities are subject to a diverse array of perturbations and in many temperate and semi-arid systems fire is a dominant structuring force. We present a novel and highly integrated approach, which quantifies, in parallel, the response to fire of pollinator communities, floral communities and floral reward structure. Mt Carmel, Israel is a recognised bee-flower biodiversity hotspot, and using a chronosequence of habitats with differing post-fire ages, we follow the changes in plant-pollinator community organisation from immediately following a burn until full regeneration of vegetation. Initially, fire has a catastrophic effect on these communities, however, recovery is rapid with a peak in diversity of both flowers and bees in the first 2 years post-fire, followed by a steady decline over the next 50 years. The regeneration of floral communities is closely matched by that of their principal pollinators. At the community level we quantify, per unit area of habitat, key parameters of nectar and pollen forage known to be of importance in structuring pollinator communities. Nectar volume, nectar water content, nectar concentration and the diversity of nectar foraging niches are all greatest immediately following fire with a steady decrease as regeneration proceeds. Temporal changes in energy availability for nectar, pollen, total energy (nectar +pollen) and relative importance of pollen to nectar energy show a similar general decline with site age, however, the pattern is less clear owing to the highly patchy distribution of floral resources. Changes in floral reward structure reflect the general shift from annuals (generally low-reward open access flowers) to perennials (mostly high-reward and restricted access flowers) as post-fire regeneration ensues. The impact of fire on floral communities and their associated rewards have clear implications for pollinator community structure and we discuss this and the role of other disturbance factors on these systems.

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Abstract-Weand five without PVD, completed testing. Subjects were tested at baseline and after receiving training with their existing prosthesis and with the study socket and four prosthetic feet, i.e., SACH (solid ankle cushion heel), SAFE (stationary attachment flexible endoskeletal), Talux, and Proprio feet, over 8 to 10 weeks. Training was administered between testing sessions. No differences were detected by the PEQ-13, LCI, 6MWT, or SAM following training and after fitting with test feet. The AMPPRO demonstrated differences following training with the existing prosthesis in the PVD group and between selected feet from baseline testing (p