Jaguars in the matrix 551
that jaguars prefer forests and avoid human-dominated and open areas (Morato et al., 2018; Costa et al., 2021; Thompson et al., 2021). The high jaguar population density and the di- versity and relative abundance of wild prey in the study area are thus remarkable, considering that the remaining natural habitat is highly fragmented and embedded in a matrix altered by human activities. The known density of jaguars estimated by camera-trap
surveys is variable throughout the species’ range. The high- est values have been reported in large areas that are little af- fected by human activities: 1–4.4 individuals/100 km2 in the Brazilian Amazon (de Oliveira et al., 2012;Tobler etal., 2013), 2.27–5.37 individuals/100 km2 in Bolivia (Maffei et al., 2004), 6.6 individuals/100 km2 in the Brazilian Pantanal (Soisalo & Cavalcanti, 2006), 5.75 individuals/100 km2 in the Maya Mountains of Belize (Silver et al., 2004), and for some Mexican subpopulations, with 4.6 individuals/100 km2 in the Montes Azules Biosphere Reserve, Chiapas (De la Torre & Medellín, 2011), 4.76 individuals/100 km2 in El Eden, Quintana Roo (Ceballos et al., 2021)and 3.5 individ- uals/100 km2 in the Chamela-Cuixmala Biosphere Reserve, Jalisco (Núñez et al., 2002). In contrast, low jaguar densities have been reported in highly fragmented landscapes: 0.3–0.5 individuals/100 km2 in the Caatinga biome, Brazil (De Paula et al., 2012)and 1.1 individuals/100 km2 in the Caribbean and Mosquita regions of Honduras (Mora et al., 2016). Why then is there such a high density of jaguars in a highly fragmented landscape in western Mexico? In conservation biology it is generally understood that
large and continuous forests are crucial for themaintenance of key ecological processes, and thus for the conservation of biodiversity (Gibson et al., 2011; Watson et al., 2018). However, recent studies have shown that small patches of remnant habitat can be of high conservation value, parti- cularly in heavily modified, human-dominated landscapes. Where no large areas of undisturbed habitat are left and small patches are all that remains, ecological processes that are not present in the altered matrix may bemaintained there (Lindenmayer, 2019;Wintle et al., 2019). Small habitat patches can thus act as stepping stones that promote pop- ulation connectivity in otherwise highly modified envi- ronments (Manning et al., 2006). They also can be nodal points for stimulating natural regeneration of modified ecosystems (Chazdon et al., 2009). The 368-ha private La Papalota Reserve lies in the core of our study area, with a mixture of well-preserved mangrove forest, deciduous trop- ical forest and secondary vegetation. La Papalota may act as a stepping stone for jaguars, connecting the southern subpopulations (San Blas and San Juan mountain) with the northern one in the Marismas Nacionales Biosphere Reserve (Luja et al., 2017). Additional factors that may contribute to the persistence of a viable subpopulation in the area are a permanent water source (the Santiago River), a sufficient supply of wild prey, and the fact that the jaguar is not hunted
in the region, neither directly nor in retaliation for attacks on livestock. A good prey base is essential for the maintenance of
healthy jaguar populations (Rabelo et al., 2019; Santos et al., 2019). In our study area, we recorded 14 species (11 mammals, two birds and one reptile) that have been re- ported as potential prey of the jaguar (Hayward et al., 2016). Previous studies showed that jaguars of this subpop- ulation prey mainly on medium-sized mammals such as the nine-banded armadillo Dasypus novemcinctus, northern raccoon Procyon lotor and white-nosed coati Nasua narica, but also on birds such as the black vulture Coragyps auratus, great egret Ardea alba and American stork Mycteria ameri- cana (Luja et al., 2020), and reptiles such as the ornate slider Trachemmys ornata (Luja & Zamudio, 2018). In other stud- ies, jaguars have also been observed preying on medium- sized prey although large prey species are available (Novack et al., 2005; Cavalcanti & Gese, 2010). Low jaguar densities are often associated with lack of prey because of poaching, and persecution (Medellín et al., 2016; Rabelo et al., 2019; Ceballos et al., 2021). Our findings show that in this part of the Mexican Pacific jaguars still have a good base of wild prey and this subpopulation is apparently not subject to poaching or persecution. A social study found that atti- tudes of local people towards the jaguar are positive and conflict related to cattle predation is minimal (Zamudio et al., 2020). Habitat fragmentation is a major threat to global bio-
diversity in general (Crutzen, 2006), and specifically to large felids (Ripple et al., 2014), including the jaguar (De la Torre et al., 2017; Thompson et al., 2021), which survives in only 40%of its original habitat (Ceballos et al., 2021). Our data showed an increase in habitat fragmentation over a 20-year period (2009–2019), with a high rate of mangrove replacement by agricultural lands and infrastructure, including rapidly expanding shrimp farms. Aquaculture has increased significantly in the region in recent decades (Berlanga et al., 2010), resulting in a reduction of natural wetland areas such as marshes. This is consistent with vari- ous locations in other countries, where shrimp farms are replacing mangroves, converting wetlands to wastelands (Thornton et al., 2003). The transformation of wetlands with natural vegetation to shrimp farms and agricultural areas results not only in habitat loss but also increases other threats to carnivores. We observed that some guards of shrimp farms were armed with shotguns and stated they would not hesitate to kill animals, including jaguars (VHL, pers. obs., 2019, 2020). In a time when more than a half of the Earth’s terrestrial
area has been modified by human activities (Crutzen, 2006), we need to understand to what extent species such as the jaguar can persist in highly fragmented landscapes (Boron et al., 2016). The Mexican Pacific is considered an important area for jaguar conservation (Medellín et al., 2016) and is the
Oryx, 2022, 56(4), 546–554 © The Author(s), 2022. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605321001617
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
