950 L. Martínez‐Domínguez et al.


five species with wide distributions converge, and for which the model predicted suitable ecological conditions for the presence of up to three additional species. The se- cond area was in the south, with mainly micro-endemic spe- cies (Fig. 3). Of the total range of Ceratozamia, 46%has been converted to anthropogenic environments (Fig. 4). Species with the smallest potential range occur in the southern area, which has been largely transformed. Agriculturally driven environmental degradation is most severe within the range of C. mexicana (Table 1); in contrast, undisturbed natural habitats persist in the northern area. Ceratozamia latifolia and C. hildae have a greater potential range in areas with original vegetation (Figs 3 & 4).


Assessment of conservation status and management strategies


FIG. 1 Modelled potential geographical range of two species of Ceratozamia: the widely distributed C. fuscoviridis and the micro-endemic C. tenuis.


The remaining eight Ceratozamia species, occurring


from the central area to the northern extreme of the region, have a wider distribution (Fig. 1). The species with the northernmost distribution, C. kuesteriana, occurs widely in two regions: El Cielo, and Canyons of Nuevo Leon and Tamaulipas. In the latter location, we did not locate this spe- cies during fieldwork. Ceratozamia fuscoviridis and C. toto- nacorum occur in the cloud forest between San Bartolo Tutotepec (Hidalgo State) and Cuetzalan (Puebla State), and in the north-west from Hidalgo to Huayacocotla in Veracruz (Fig. 2). The distribution of C. totonacorum includes part of the SierraNorte de Puebla-Chiconquiaco region.Cera- tozamia hildae and C. latifolia are located in north-west Hidalgo and as far as Huayacocotla, with vestiges in the San Luis Potosí region; the potential distributions for these two species overlap almost completely. Ceratozamia delucana is restricted to the Sierra Norte de Puebla-Chiconquiaco region and to a small cloud forest area in north-west Hidalgo and Huayacocotla, whereas C. chamberlainii and C. sabatoi inhabit a single forest area (Fig. 2).


Species richness and land use


We observed two areas of particularly high species richness. One was in the northern part of the study area, where


Most Ceratozamia species (92%) are under ex situ conser- vation in botanical gardens (Table 1). These species occur in seven protected areas (Table 1). The Sierra Gorda Bio- sphere Reserve contains three species (C. chamberlainii, C. sabatoi and C. hildae). According to their potential range, C. kuesteriana and C. fuscoviridis could occur in the Altas Cumbres Federal Reserve, in the Chicamole ecological pres- ervation municipal area (Fig. 5a), but we were unable to confirm this during fieldwork. The distribution of Ceratozamia mostly overlaps with


several priority areas for conservation, including areas of high species richness in the northern part of the study area. This area is thus of particular importance for the con- servation of the genus (Fig. 5b). The range of Ceratozamia in the mountains of the north and central Sierra Madre Oriental, and the southern part of the range of the genus, overlap with three priority biological and cultural areas for conservation and development (Fig. 3). Forests are less affected by anthropogenic pressures in two of these areas (Fig. 4). According to their current categorization in the IUCN Red List (IUCN, 2017) and the Mexican list of threat- ened species, NOM-059-SEMARNAT-2010 (SEMARNAT, 2010), the species with the highest risk of extinction are those that have experienced less habitat loss. For example, C. kuesteriana has a relatively broad distribution but is categorized as Critically Endangered on the IUCN Red List. In contrast, C. mexicana is categorized as Vulnerable but occurs in an area with rapid loss of habitat (Supplementary Table 3, Figs 2c & 4). This suggests that the extinction risk of these species should be re-evaluated to align the categorization with actual threat levels. In our survey of the two nurseries, we found that although


approaches varied, outcomes were similar. Tachinola nursery is an Ejidal organization (a form of communal property/ territory common in rural Mexican regions) in operation since 1995, whereas Dos Cerros nursery is a private initiative


Oryx, 2021, 55(6), 947–956 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605320000204


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