The land crab Johngarthia planata (Stimpson, 1860) (Crustacea, Brachyura, Gecarcinidae) colonizes human-dominated ecosystems in the continental mainland coast of Mexico

Abstract

The land crab Johngarthia planata (Stimpson, 1860) has been reported from the Baja California Peninsula and several oceanic islands in the Eastern Pacific as well as inshore islands of the Mexican, Costa Rican and Colombian coast. However, the species has not been observed on the continental mainland, as it is likely that the high diversity of terrestrial predators/competitors make the establishment of mainland populations nearly impossible. In this contribution, several new records of this species that have been observed in urban areas along the continental Pacific coast of Mexico are reported. These records demonstrate that the presence of humans does not necessarily have a negative impact on land crab species. Indeed, the presence of humans may actually discourage the presence of native crab predators/competitors and hence increase the likelihood of a successful mainland settlement of land crab species that are otherwise island and peninsula restricted. The presence of Johngarthia planata is ecologically relevant for coastal forests because gecarcinid crabs significantly influence plant recruitment and Johngarthia planata is considerably larger than the mainland species Gecarcinus quadratus.

Terrestrial crustaceans (Arthropoda, Crustacea): taxonomic diversity, terrestrial adaptations, and ecological functions

“…Many terrestrial macrocrustaceans are invaders or synanthropes that successfully colonize transformed ecosystems, urban areas, and other anthropogenic habitats such as parks and gardens ( Perger et al 2013 ; Perger 2014 ). Woodlice are among the most numerous groups of epigeic arthropods in the transformed habitats ( Philpott et al 2014 ; Hornung et al 2015 ), where the likelihood of successful settlement of invasive species is increased due to suppressed activity of native predators or competitors ( Sorensen and Burkett 1977 ; Szlavecz et al 2018 ).…”

Population biology of the endangered land crab Johngarthia lagostoma (H. Milne Edwards, 1837) in the Trindade Island, Brazil: Identifying crucial areas for future conservation strategies

“…This is probably due to the reduced establishment of predators in island environments, where land crabs occupy vacant niches (Andrades et al., 2019). In addition, insular crabs can travel large distances on the land‐sea gradient (Perger, 2014; Vermeij & Dudley, 2000), with adults residing in higher altitude areas (>1000 m) and migrating over great distances in the scale of kilometers to reach the coast for breeding (Hartnoll et al., 2006a, 2009; Hicks, 1985). The migration of the Christmas Island red crabs ( Gecarcoidea natalis ) is a classic example; the adults move in large numbers from the forests where they live to the beaches where they engage in reproductive behavior, and then the recruits move back to their parent's habitat (Adamczewska & Morris, 2001; Hicks, 1985).…”

The description of a new species of the Neotropical land crab genus Gecarcinus Leach, 1814 (Crustacea, Decapoda, Brachyura, Gecarcinidae)

“…On some islands their biomass may exceed the total mass of animals reported in tropical rain forests in Costa Rica and the central Amazon ( Lindquist et al 2009 ) and they may occupy the top of the energy pyramid ( Burggren and McMahon 1988 ). Nevertheless, despite their success on islands and the possibility of dispersal of their marine larvae via ocean currents, most species of these genera are absent from continental mainland habitats ( Türkay 1987 ; see also Perger 2014 for a short review). Only Johngarthia planata (Stimpson, 1860) (see Perger 2014 ) and two populations of the Neotropical genus Gecarcinus are successfully established on the continental mainland.…”

“…Nevertheless, despite their success on islands and the possibility of dispersal of their marine larvae via ocean currents, most species of these genera are absent from continental mainland habitats ( Türkay 1987 ; see also Perger 2014 for a short review). Only Johngarthia planata (Stimpson, 1860) (see Perger 2014 ) and two populations of the Neotropical genus Gecarcinus are successfully established on the continental mainland. The Atlantic population, known as Gecarcinus lateralis (Fréminville, 1835), occurs along mainland beaches from Florida to Venezuela ( Türkay 1970 ) and is partially sympatric with Gecarcinus ruricola (Linnaeus, 1758), which is restricted to Western Atlantic islands.…”