Anfibios y reptiles de las Islas Marías y otras islas adyacentes a la Costa de Nayarit, México. Aspectos sobre su biogeografía y conservación

Abstract

THE ARE TREE GROUPS OF CONSPICUOUS CONTINENTAL ISLANDS IN FRONT OF NAYARIT, MEXICO: ISABELA, THAT HAS SIX REPTILIAN SPECIES, MARIAS CONTAINING THREE AMPHIBIAN AND 24 REPTILIAN SPECIES AND TRES MARIETAS THAT HAS SIX REPTILIAN SPECIES. ISABELAS HERPETOFAUNA IS FAIRLY SIMILAR (80 - 100%) TO THE ONE AT THE COAST OF SINALOA AND NAYARIT; THE HERPETOFAUNAS OF MARIAS AND MARIETAS ARE SIMILAR (75 - 100%) TO THOSE IN THE COAST FROM SINALOA TO MICHOACAN; THERE IS NOT SO MUCH SIMILARITY (25 - 60%) BETWEEN THE ISLAND GROUP HERPETOFAUNAS. THE AMPHIBIANS AND REPTILES OF MARIAS AND ISABELA ISLANDS POSSIBLY ORIGENATED SINCE THE MIDDLE PLIOCENE. ENDEMIC SPECIES OF THIS FAUNA ARE UNKNOWN FROM THE ISLANDS. SPECIES - AREA RELATIONSHIP IS LINEAL AND THE STRAIGHT LINE EQUATION CALCULATED WAS: S = (0.4931) A 0 4/!. IF THE EQUATION OF PRESTON (1962) Z 0 0.301, COMPUTED FOR THE WEST INDIES, IS USED ISTEAD OF THE ONE CALCULATED FOR MARIAS, THE EXPECTED FAUNA IS JUST HALF OF THE SPECIES ACTUALLY OBSERVED, SO THE RICHNESS OF AMPHIBIAN AND REPTILE SPECIES IS HIGH, COMPARED TO THOSE OF WEST INDIES. ISABELA AND TRES MARIETAS SHOW A SUPERSATURATION OF SPECIES. AMONG THE ISLANDS STUDIED. MARIA MADRE SHOWS THE HIGHER ENVIROMENTAL DISTURBANCE; BECAUSE OF THEIR ABUNDANCE IN THE ISLAND, IT LOOKS LIKE THERE ARE 10 SPECIES OF REPTILES THAT MAY BE RESISTING THAT DISTURBANCE BUT IT IS DIFFICULT TO PREDICT FOR THE REST OF THE SPECIES; VULNERABLE SPECIES HAVE TO BE EVALUATED IN ORDEN TO KNOW THEIR CONSERVATION STATUS, AND IN CASE OF DETERIORATION IT WILL BE RECOMMENDABLE TO APPLY METHODS OF CONSERVATION BASED IN THE THEORY OF THE BIOGEOGRAPHY OF ISLANDS.