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Land-use changes are expected to affect plant-disperser conditional mutualisms through changes in animal behavior. We analyzed the oak-rodent conditional mutualism in Mediterranean fragmented forests at two climatically different locations. We quantified fragmentation effects on seed dispersal effectiveness and assessed if such effects were due to changes in habitat structure and intraspecific competition for acorns in fragmented areas. Fragmentation decreased cover from predators within mouse territories as well as intraspecific competition for acorns. This resulted in lower dispersal effectiveness in small forest fragments. Globally, habitat structure was the main driver in mouse foraging decisions. In small fragments, low shelter availability precluded mouse movements, leading to short mobilization distances and low caching rates. However, as the proportion of cover from predators increased, mice were able to modulate their foraging decisions depending on intraspecific competition for acorns, resulting in higher dispersal quality. In addition to fragmentation effects, delayed breeding in the southern locality caused lower number of rodents during the dispersal season, which reduced acorn mobilization rates. Our study shows that seed dispersal patterns in managed systems can be analyzed as the result of management effects on key environmental factors in dispersers' foraging decisions.

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We determined the individual and population responses to food availability of wood mice Apodemus sylvaticus wintering in small forest woodlots by means of a food addition experiment. The allocation of the extra provided energy to the maintenance of body condition and reproduction was expected to vary between sexes due to their different energy investment in reproduction and to the different indirect costs of reproduction associated with different hormone-mediated susceptibilities to parasite infections.There were no effects of food supplementation on the density of adult males or on the overall density of mice. However, adult females were marginally more abundant and the sex ratio was more balanced in supplemented woodlots. Body condition (as estimated by body mass, body mass relative to body size, and amount of fat reserves), did not differ among treatments for either adult males or females. The prevalence and intensity of endoparasites of short life cycle (oxyurid nematodes) were lower in food-supplemented woodlots than in controls and lower in females than in males. No differences were found for endoparasites with long life cycles (telacid nematodes and cestodes). Males with intermediate parasite loads were in better body condition than either nonparasitized or highly parasitized individuals, and the body condition of each group of males was better in foodsupplemented woodlots than in controls. This nonlinear relationship between parasite loads and body condition was apparently due to indirect costs of reproduction in control woodlots, where there was a direct relationship between male reproductive effort (relative testis size) and parasite loads. This relationship was not found in supplemented woodlots.Most individuals were breeding actively at the end of winter. Males had larger testicles, and females showed an advanced breeding, and probably enhanced survival and larger litter sizes, in supplemented woodlots. Individual mice wintering in Mediterranean fragmented forests are thus food limited, and directed most of the extra provided food resources to reproduction without losing body condition or antiparasite abilities. This enhanced reproduction, rather than improved body condition, may translate into larger population densities and recruitment.

The houbara bustard in the Canary Islands is included into the category 'Endangered' on the Spanish Bird Red List according to suspected declines in bird numbers, the loss of previously occupied areas and the suggested endemicity of the taxon. This paper deals with the population size and the distribution pattern of the houbara bustard in Fuerteventura (the largest island occupied by the species in the Canary archipelago, 1730 km 2 ) and analyses its habitat use according to topography, soil, vegetation and human impact variables. We employ distance sampling on 1471 (early spring) and 602 (summer) 500-m transects and measure habitat characteristics within the transects to estimate local densities and population sizes and to test whether the features of the used habitats (as measured in transects where the species was recorded) differed from those available (measured in the whole sample). Topographic and anthropic features are the main determinants of the habitat use of the species, while other descriptors related to vegetation structure and substrate characteristics play a minor role in its habitat preferences. The slope of the terrain is the most important habitat feature constraining the occurrence of the houbara bustard. The proximity of urban areas, the density of paved roads and rural tracks and the extension of agricultural fields also adversely influence its distribution pattern in Fuerteventura. These habitat patterns does not change between summer and early spring considering the whole population of the species (i.e. without considering sexual or agerelated differences). Population size is estimated at 177 birds for the whole Fuerteventura island during the breeding season (90% confidence interval: 108-258 birds). Only five areas comprising 247 km 2 include 80.8% of the total population in this island, although four of them are not included into the regional network of protected natural sites.