774 Y. Yom‐Tov et al.


FIG. 3 Connectivity of the mountain gazelle population in (a) core regions in the Mediterranean region and (b) central Israel, where connectivity of gazelle populations is particularly hampered, with the main barriers preventing free movement between populations. The connectivity index is a function of permeability for gazelle movement to adjacent populations (see text for full details, and Supplementary Table 1).


main areas of gazelle concentrations, (2) occasional obser- vations of gazelles routinely reported by Israel Nature and Parks Authority rangers (the database comprised 72,437 observations recorded during 1973–2018), and (3) observa- tions and counts of gazelles by AB and EH in the Jerusalem corridor and Judean Mountains and foothills, respectively (Fig. 2). For each core area we calculated the degree of fragmen-


tation in two stages. Initially we used a map of land use (Sorek & Perevolotsky, 2016) to identify human dominated landscapes (i.e. built environments, roads, railways), and ha- bitats that are permeable to gazelles such as natural vegeta- tion and agricultural fields. Each pixel (150 m2) was given a permeability score based on its property of enabling or hampering gazelle movement (see Supplementary Table 1 for permeability score values per land-use category). We then summed these scores outwards from each core area to create its connectivity area. For each connectivity area the perme- ability values were summed up to 6 km away from each core region, or up to a maximum of 6,000 permeability score units. In fragmented regions with high human disturbance, the 6,000 units threshold was reached before the 6 km limit, and thus the connectivity areas were smaller. We then cal- culated a connectivity index for each core area as (core area + connectivity area)/core area. Completely isolated core areas have an index value of 1, whereas higher index values indicate higher connectivity from the core areas outwards. Figure 3 displays the connectivity index for each core area, highlighting regions where gazelles reside and their con- nectivity.


This first stage did not take into consideration all possible


causes of fragmentation, such as fences,most ofwhich do not appear on the available maps. To account for such obstruc- tions, we consulted with regional Israel Nature and Parks Authority rangers. In cases where obstruction to free move- ment of gazelles exists we changed the category of each core area by altering the relevant permeability scores and recalcu- lating the connectivity index (Fig. 3). All spatial analysis was carried out in ArcMap 10.3 (Esri, Redlands, USA).


Threats


A combination of several major threats limits the growth of the Israeli gazelle population and/or causes its decline.


Habitat destruction and change


The impact of human settlements on gazelles may extend beyond dwellings and is considerably greater than the actual loss of suitable grazing land. Gazelles have been recorded to perceivehuman presence as a threat, with an increased flight distance with higher human presence and a positive corre- lation of vigilancewith extent of disturbance (Manor&Saltz, 2004, 2005). Gazelle pellet counts have indicated partial avoidance at least 700 m into natural habitats bordering human habitations (Manor&Saltz, 2005). Strong avoidance of human dwellings and their vicinity by gazelles has been confirmed using camera-traps (Sorek&Perevolotsky, 2016).


Oryx, 2021, 55(5), 771–778 © The Author(s), 2020. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S003060531900108X


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164