In social ungulates, the proportion of time devoted to vigilance is a function of group size (known as the group size effect). We studied how varying levels of human disturbance influence this function in the mountain gazelle (Gazella gazella) along the southern coastal plain of Israel. Based on current theory, we predicted that changes in the slope of this function should be associated with changes in average group size. In heavily disturbed areas, individual vigilance levels increased in the bigger groups, causing the vigilance vs. group size curve to flatten, i.e., vigilance was high in all group sizes. Consequently, and in accordance with theory, we found a negative relationship between group size and human disturbance. Specifically, we found that in open areas with low disturbance levels, gazelles were in bigger groups than in open areas with high disturbance levels. In social species, the disruption of behavioral patterns by increased human presence can affect their social structure. Because social structure is a key component in the evolution and dynamics of social species, its disruption by human disturbance can have a considerable effect on population performance even if the disturbance does not directly impact survival and reproduction. Social disruption due to increased access to natural areas should be an important consideration in managing fragmented landscapes.

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The ecological consequences of homogenization remain relatively unexplored. One example of landscape-homogenizing is the establishment of plantations. We studied the effect of human-made forests by contrasting plant and small-mammal community composition between planted tree stands and adjacent natural habitat in two different Mediterranean habitats in Israel: (1) inland habitat where we focused on pine (Pinus halepensis) and carob (Ceratonia siliqua) stands, and (2) coastal sand dune habitat where we focused on planted acacia (Acacia saligna) stands. We first wanted to verify whether planted trees modify plant species composition, and second, if and how the small-mammal community is affected by the different habitat conditions created in plantations with different canopy cover. We were especially interested in the abundance of the commensal house mouse (Mus musculus). All tree stands underwent biotic homogenization indicated by abundance of house mice coupled with lower diversity of indigenous vegetation and small-mammal abundances and diversities. Habitat structural diversity was positively related with small-mammals diversity and was lower in artificial tree stands in both habitats. Our results suggest that using the abundance of commensal generalist species such as the house mouse relative to other more specialist small-mammals is a good approach to determine ecosystem integrity. Precommercial thinning treatment is a potential management tool to maintain a proportion of native tree species within the canopy of planted tree stands. However, until sufficient data is available for making generalizations, the exact level of thinning necessary to reverse the homogenization processes in man-made plantations and keeping indigenous small-mammal communities diverse and less prone to invasion must be determined empirically.

We studied the impact of proximity to human concentrations, hikers, and field vehicles on mountain gazelles (Gazella gazella gazella) space-use patterns, flight distance, and visibility in the southern coastal plain of Israel. We collected data on gazelle behavior and human disturbance from fixed observation sites, drive counts, and pellet counts. The density of pellets was positively correlated with the distance to human concentrations, and the flight distance was positively correlated with human disturbance level, suggesting mountain gazelle space use and flight distance were affected by human disturbance. Gazelles were less visible in the more disturbed areas. Our findings provide a framework for conservation measures such as determining the size of buffer zones and where and when enforcement efforts should take place to keep mountain gazelle populations viable in spite of the ecological impacts of human encroachment on mountain gazelle habitat. JOURNAL OF WILDLIFE MANAGEMENT 69(4):1683-1690; 2005

Density dependent habitat selection at the community level is regarded as a major determinant of biodiversity at the local scale, and data on these processes and how they are affected by human activities is highly applicable to conservation. By studying the competitive relationships between a specialist and a generalist we can acquire valuable insights about how different environmental elements determine species abundance and distribution and consequently biodiversity. Here we describe a study of density dependent processes that determine the community structure of two rodents: a specialist-the broad toothed mouse (Apodemus mystacinus), and a generalist-the common spiny mouse (Acomys cahirinus) in a Mediterranean maqui habitat, and how this structure is impacted by anthropogenic planting of pine stands. We carried out two field experiments: The first, based on open field trapping, looking at how rodent communities change with habitat structure. The second experiment was an enclosure study aimed at validating the habitat preferences and competitive relationship between the specialist and the generalist. We identified asymmetric competition relationships in which the specialist was dominant over the generalist. Competition intensity was lower in maqui with [10% oak cover, although both species abundances were high. Competition was found only during the limiting season (summer). Based on these findings we produced management recommendations to keep indigenous small mammals' biodiversity high. Density dependent habitat selection processes play a central role in determining biodiversity, and understanding the mechanisms motivating these processes is needed if alterations in biodiversity in response to human disturbance are to be understood.

Although there is adequate knowledge on restoring many invaded habitats, information regarding faunal recovery is still lacking, particularly regarding sandy coastal ecosystems. An important challenge for assessing restoration effectiveness is the selection of an appropriate bioindicator. The current study examined the recovery of psammophilic rodents and reptiles following the removal of Acacia saligna from Mediterranean coastal dunes. Rodents and reptiles were monitored for 3 years after the tree removal. Rodent sampling included live trapping; reptile sampling included pitfall traps, track transect trails and transect walks (daylight and dark). Removing the invasive plants improved the recovery conditions for psammophilic reptiles and rodents, including endemic and threatened species. However, reptiles differ from rodents in their physiological and behavioral mechanisms, including thermoregulation, diet and territorial behavior, allowing them to respond to habitat changes quicker than rodents. Within the reptile group, faster recovery was observed for nonterritorial species than for territorial species. It is necessary to consider the suitable taxa, method, and time for evaluation of habitat recovery. Our study demonstrates that monitoring reptiles by combining three methods (1) pitfall traps, (2) track transect trails, and (3) transect walks during daylight and dark provides a more complete picture, which is difficult to achieve from a single method. Furthermore, in the case of invasive transformer plants such as A. saligna, which cause long-term effects, we conclude that monitoring both taxonomic groups is advantageous, as this provides a more reliable picture of ecological functioning and faunistic recovery (compared to monitoring only one of the taxa).