R. Villafuerte

Historical examination of the status of large mammals in Aragon, Spain

Summary. - During the last century, human activities have promoted large changes in habitats, leading to changes in the abundance and composition of mammal communities. Some species have been favoured intentionally (specially those with high economic importance), or unintentionally (Le. opportunistic species), introduced (as some livestock species), or persecuted (Le. species that affect livestock or game). In this paper, we show and explain the changes in the composition of the large mammal community in Aragon, a northeastern Spanish area where there have been extinctions (lynx, Lynx sp.); introductions (moufflon, Ovis ammon; fallow deer, Dama dama); reintroductions (red deer, Cervus elaphus); and particularly natural expansions (wild boar, Sus scrota ; roe deer, Capreolus capreolus ; red deer; Pyrenean chamois, Rupicapra pyrenaica pyrenaica). Some taxa are currently almost extinct (brown bear, Ursus arctos; Pyrenean ibex, Capra pyrenaica pyrenaica) and others are recovering after getting close to extinction (wolf, Canis lupus). Three interconnected causes may explain the clear increment of ungulates in our study area: (1) the abandonment of rural activities, (2) the subsequent decrease of livestock, and (3) the increase of forest habitats. None of those species are currently below 150 % of their range in the 19th century. The setting up of hunting reservations and the design of a hunting legislation have also contributed to the observed changes. Traditionally, large predators have not been favoured by human activities, while compensatory protection measures carried out have been scarce or came too late. While some of these species are probably extinct in the area, the remaining occupy currently less than one fourth of their former range and need urgent conservation measures for to recover.

The effect of exclusion of terrestrial predators on short-term survival of translocated European wild rabbits

Many translocation methods have been tested in southern Europe in recent decades to increase the translocation success of the European wild rabbit (Oryctolagus cuniculus L.) for both conservation and game purposes. The main problem experienced during such translocations is the high short-term (7 days) mortality attributed to predation during the days immediately following rabbit release. In this study, we test the effect of the exclusion of terrestrial predators on the survival of translocated rabbits for recovery purposes. Four translocation plots (4 ha with 18 artificial warrens each) were constructed, two of them with a fence to exclude terrestrial predators. In all, 724 rabbits were released to the translocation plots in five batches and forced to remain inside warrens for 7 days. Following liberation, exclusion of predators did not increase rabbit survival in the short term. Contrary to expectations, three months after release, survival of rabbits in the unfenced plot was slightly, but not significantly, higher than in the fenced plot (0.57 and 0.40 respectively). Although predator control is a frequent management practice associated with rabbit translocations, our results suggest that it may not favour rabbit survival rate as much as the adaptation of rabbits to the release site.

Descriptive study of an avian pox outbreak in wild red-legged partridges (Alectoris rufa) in Spain

This study describes the dynamics and epidemiology of an outbreak of avian pox in free-living, red-legged partridges (Alectoris rufa) in southern Spain. Between March 2000 and January 2001, 115 free-living, red-legged partridges (70 juveniles, 45 adults) were captured and radio-tagged. This, together with the necropsy of 44 carcasses (10 juveniles, 34 adults) found in the study area, and the inspection of 108 shot birds (74 juveniles, 34 adults) after a hunting drive in October, permitted a close monitoring of the course of the disease. Forty-one per cent of radio-tagged juveniles but none of 45 radio-tagged adults showed pox-like lesions at the time of capture, recapture, or necropsy. At least 40% of the juveniles that survived into the hunting season, but only 2.9% of the adults inspected at the same time, showed lesions suggestive of infection with avian poxvirus. The survival of juveniles during the peak of the outbreak was much lower than that of the adults, but we found no significant differences between the survival probabilities of juvenile partridges with and without pox-like lesions. Nevertheless, some birds may have developed lesions after their capture. The occurrence and course of the disease in a managed area with intense predator control underlines the need for studies on the combined influence of diseases and predators on population dynamics. Also the need for early detection of diseases for the management of game species is emphasized.

Pathology of Avian Pox in Wild Red-Legged Partridges (Alectoris rufa) in Spain

Abstract: The diagnosis and pathology of an avian pox outbreak in free‐living red‐legged partridges in Cádiz, Southern Spain, is described. Diagnosis of the disease was based on histopathology, ultrastructural examination of, and virus isolation from lesions of necropsied animals. Lesions were present mainly in juvenile partridges (41%), and were observed primarily on the dorsal part of the digits or on the hock joint. The lesions ranged from small wartlike nodules to large tumor‐like lesions. The presence of acute lesions of any grade as opposed to absence of lesions or healed lesions adversely affected body condition of the partridges (P < .01). Further investigations on the epidemiology of the disease and on the relation of the isolated strains to other avian poxviruses are under way.