As migratory animals, sustainable management of African elephant populations, both within and around protected areas, is a major challenge in the conservation policy of many African countries. We captured seven female elephants, representative members of family groups, in different parts of Tarangire National Park (TNP), Tanzania, and used GPS satellite radio-tracking (November 1997-June 2000 to monitor their space and habitat use and seasonal migrations throughout wet and dry seasons. Patterns of home range overlap revealed the existence of two large clans that occupied the north-central and southern parts of TNP, respectively. At the end of the dry season, elephants from the southern clan migrated about 100 km southeast of the park boundary, those from the northern clan remained mostly inside the park, or used periodically wet-season core areas in the nearby Game Controlled Areas. No natural mortality occurred during the study, but two elephants were poached outside the park. Human disturbance also affected activity patterns, and elephants were less active at day outside than inside the park. Home range size varied from 477 to 1078 km 2 for the northern elephants, and from 1630 to 5060 km 2 for the southern elephants. Migration routes were characterised by higher cover (open and closed forest) than core areas. Our results indicate that elephant management must be considered across park boundaries and that migration corridors must be protected against human disturbance and land cultivation. Society problems linked to elephant conservation can be solved by creating alternative, sustainable, use of natural resources that enhance the livelihood of local communities.

In heterogeneous environments, differential niche selection by two competing species will result in niche partitioning so that individuals of each species can maximise their fitness under different sets of environmental variables. Thus, niche partitioning is considered essential to allow co-existence of ecologically related species. To assess whether niche partitioning was occurring between native red squirrels and alien grey squirrels living together in a 13-ha high-quality mixed deciduous woodland in north Italy, we investigated temporal and spatial patterns in their activity and foraging behaviour between 1996 and 1998. We used live trapping and radio-tracking to study numbers, distribution and behaviour of squirrels. Daily and seasonal temporal activity patterns, and activity on the ground and in the trees, were similar in the two species. However, grey squirrels were more tree specialists and had a narrower tree-species niche width than red squirrels, in particular making greater use of oak. Other studies of red and grey squirrels in allopatry show that the two species differ in the extent they utilise oak. Overall, tree-species niche overlap was about 70%. Grey squirrels had larger home ranges than red squirrels. Home ranges and core areas of both species were larger in males than females. Also, intraspecific home range and core-area overlap patterns were similar to those found in allopatric populations of these species. Overall, there was no evidence that the use of space of one species was affected by the other. Our results show that there was no niche partitioning of activity or foraging behaviour in time or space during the study. This suggests that, at moderate grey-squirrel densities, red squirrels are unable to avoid competition with grey squirrels, and that competition for food and/or space will occur when these resources become limiting

Introduced mammals can cause extinction of native species due to replacement competition, disease, predation or hybridization. We studied the colonization of Piedmont (NW-Italy) by American grey squirrel (Sciurus carolinensis) and its effect on the native red squirrel (Sciurus vulgaris). Presence/absence data (2x2 km squares), of both species were (re)constructed using questionnaires, literature, existing databases, unpublished information, and direct monitoring with hair-tubes. In 1970 red squirrels were still widespread and greys were restricted to forests near the introduction site. By 1990, grey squirrels had increased their range to 220 km 2. , which coincided with the disappearance of native squirrels from 33 squares inside this range. The invasive species continued its spread occupying an area of 2,016 km 2 in 2010; within this area red squirrels went extinct in 88 squares. Overall, from 1970 to 2010 red squirrel went extinct in 62% of 2x2 km squares (ca. 1,689 km 2 ), and were replaced by grey squirrels. The spread of the alien species was slow in the first twenty years, but doubled in the successive two decades. Nevertheless spread was slower than in Ireland and England. Grey squirrel adapt to climate and habitats in both North and South Europe, causing extinction of the native red squirrel. A EU LIFE co-funded project with the aim to control the grey squirrel in North Italy and recent trade-restrictions and trade-ban are a first step in reducing the risk of grey squirrels invading other countries, but their effectiveness will have to be evaluated.

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Variation in intrinsic (body mass, reproductive condition) and extrinsic factors (habitat quality, spatiotemporal variation in food availability) can affect the costs and benefits of personality traits. Relationships between personality and fitness components can vary with changes in population density and/or habitat quality. Here, using capture-mark-recapture data of individually marked Eurasian red squirrels (Sciurus vulgaris), we explored whether indices of boldness and exploration are correlated with local survival in either of the sexes and with a measure of reproductive success in females, under different conditions of food availability. PCA scores derived from the number of captures (trappability) and number of different traps where an individual was captured (trap diversity), in the first one or two years of presence, were used as indices of personality (boldness and pure exploration). The relationships between boldness and local survival differed between habitats in both sexes. Bold squirrels survived better than shy ones in Norway spruce forest, while in the other two study areas (Scots pine, or mixed spruce-fir forest) survival was lower for bolder squirrels. Pure exploration behavior was negatively correlated with local survival in all habitats and in both sexes. Female reproductive success increased with body mass and decreased with the tendency to explore, a relationship consistent across habitat types. Bolder females did not have a reproductive advantage in years of poor food availability. We suggest that costs and benefits of boldness vary with spatio-temporal differences in availability of high-quality food resources which may help to maintain variation in personality in red squirrels in heterogeneous landscapes.

Aim The establishment and spread of invasive alien species may be influenced by several mutually interacting factors, whose understanding is paramount to develop effective biosecurity policies. However, studies focused on modelling spatially explicit patterns of future invasion risk have so far focused on species response to climate change impacts, while land‐use change has been neglected. We investigated how the interplay between climate and land‐use change could affect the future potential distribution and dispersal corridors of four alien squirrels introduced to Europe (Sciurus carolinensis, Callosciurus finlaysonii, Callosciurus erythraeus and Eutamias sibiricus). Location and Methods Our study was conducted in Italy. We used Species Distribution Models and circuit theory methods to test whether future scenarios based only on climate change predict a different effect on range and connectivity of alien squirrel populations, compared to scenarios that include both climate and land‐use changes. Results Scenarios based only on climate change predicted a range increase and a high geographic stability (>50%) for most species, with different, yet limited, effects on connectivity corridors. Conversely, scenarios based on both climate and land‐use change showed a loss in range extent and a low geographic stability (<50%) of both range and dispersal corridors for most species. Main conclusions Scenarios considering both climate and land‐use change provide predictions on invasion risk that overturn those including only climate change. The effect of global warming alone would lead to a considerable range expansion of all species. Conversely, when land‐use change is added, a potential loss in suitable habitat and dispersal corridors is predicted for alien squirrels, hence limiting their range expansion. We recommend using multiple drivers in models to obtain reliable predictions for implementing biosecurity policies related to invasive alien species.

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Animal dispersal and subsequent settlement is a key process in the life history of many organisms, when individuals use demographic and environmental cues to target post-dispersal habitats where fitness will be highest. To investigate the hypothesis that environmental disturbance (habitat fragmentation) may alter these cues, we compared dispersal patterns of 60 red squirrels (Sciurus vulgaris) in three study sites that differ in habitat composition and fragmentation. We determined dispersal distances, pre-and post-dispersal habitat types and survival using a combination of capture-mark-recapture, radiotracking and genetic parentage assignment. Most (75%) squirrels emigrated from the natal home range with mean dispersal distance of 1,014 ± 925 m (range 51-4,118 m). There were no sex-related differences in dispersal patterns and no differences in average dispersal distance, and the proportion of dispersers did not differ between sites. In one of the sites, dispersers settled in patches where density was lower than in the natal patch. In the least fragmented site, 90% of animals settled in the natal habitat type (habitat cuing) against 44-54% in the more strongly fragmented sites. Overall, more squirrels settled in the natal habitat type than expected based on habitat availability, but this was mainly due to individuals remaining within the natal wood. In the highly fragmented landscape, habitat cuing among emigrants did not occur more frequently than expected. We concluded that increased habitat fragmentation seemed to reduce reliable cues for habitat choice, but that dispersing squirrels settled in patches with lower densities of same-sex animals than at the natal home range or patch, independent of degree of fragmentation.