Sea turtles are reptiles that have inhabited the earth for 100 million years. These are divided into 2 families (Cheloniidae and Dermochelyidae) and 7 species of sea turtles in the world: the leatherback turtle (Dermochelys coriacea); hawksbill turtle (Eretmochelys imbricata); Kemp’s ridley (Lepidochelys kempii); olive ridley (L. olivacea); Loggerhead turtle (Caretta caretta); flatback sea turtle (Natator depressus) and green turtle (Chelonia mydas). In particular, Kemp’s ridley is included in the red list of IUCN categorized as “critically endangered”. The most important site around the Word is in Rancho Nuevo, Tamaulipas, Mexico. Where 80–95% of the world’s nesting is concentrated. Other nesting areas are Tepeguajes and Barra del Tordo, in Tamaulipas, and with less intensity in Veracruz (Lechuguillas and El Raudal beaches) and South Padre Island, Texas, USA. They deposit an average of about 90 eggs and hatching takes 40 to 60 days. Therefore, they are vulnerable to different anthropogenic activities and sources of pollution, such as heavy metals, which can cause toxic effects that are harmful to the turtles, damage their physiology and health. To understand the real situation about health and genetic parameters it is necessary to analyze biochemical and molecular factors in this species.

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In Mexico, studies on chiropters have reported the presence of eight families and a total of 138 species, of which seven families and 55 species are reported for the state of Sinaloa. However, the Sierra de Navachiste, México is a natural protected area of state jurisdiction registered as an area subject to Ecological Conservation. studies on bat populations in this area are scarce or nonexistent, resulting in their environmental needs, current threats and the impact they have at population level being unknown. Despite finding a low species richness (five species), caught two migratory species in Sierra de Navachiste: Mormoops megalophylla and Leptonycteris yerbabuenae. This last bat is included on the IUCN red list (International Union for the Conservation of Nature) as a "vulnerable" species, and in Mexico it is a "threatened" species. This bat is considered a key species within the ecosystem due to being the pollinator of the dominant columnar cacti as well as a distributor of its seeds though fruit consumption. This activity promotes the dispersal of these plants and maintains the structure and health of the ecosystem. Due to the importance of the Sierra Navachiste as a refuge for at least five bat species, including two migratory and one protected species, it is necessary to establish a management plan in order to protect the chiroptera community that depends on it.

The concentrations of trace elements including As, Zn, Cu, Se, Pb, Hg and Cd, were determined in the blood of nesting Kemp’s ridley turtles (Lepidochelys kempii) at Rancho Nuevo sanctuary, Tamaulipas, Mexico during 2018–2020. The sequential concentrations analyzed were Zn> Se> Cu> As> Pb; while Cd and Hg concentrations were below the limits of detection (0.01 μg g-1). No significant differences were observed between the concentrations of trace elements (p> 0.05) by year, except Se levels, possibly resulting from recorded seasonal differences in turtle size. No relationships among turtle size vs elements concentration were observed. In conclusion, essential and toxic trace elements concentrations in the blood of nesting Kemp’s ridley turtles may be a reflex of the ecosystem in which the turtles develop, that is, with low bioavailability of elements observed in the trophic webs in the Gulf of Mexico.

The concentrations of heavy metals and metalloids including As, Zn, Cu, Se, Pb, Hg and Cd, were determined in the blood of nesting Kemp’s ridley turtles (Lepidochelys kempii) at Rancho Nuevo sanctuary, Tamaulipas, Mexico during 2018-2020. The sequential concentrations of metals analyzed were Zn> Se> Cu> As> Pb; while Cd and Hg concentrations were below the limits of detection (0.01 µg g−1). No significant differences were observed between the concentrations of metals (p> 0.05) by year, except Se levels, possibly resulting from recorded seasonal differences in turtle size. No relationships among turtle size vs metal concentration were observed. In conclusion, heavy metals concentrations in the blood of nesting Kemp’s ridley turtles may be a reflex of the ecosystem in which the turtles develop, that is, with low bioavailability of metals observed in the trophic webs in the Gulf of Mexico.