RESUMEN
Habitat loss and fragmentation, together with related edge effects, are the primary cause of global biodiversity decline. Despite a large amount of research quantifying and demonstrating the degree of these effects, particularly in top predators and their prey, most fragmented patches are lost before their conservation value is recognized. This study evaluates terrestrial vertebrates in Playa Sandalo, in the Osa Peninsula of Costa Rica, which represents the last patch of "primary" forest in the most developed part of this region. Our study indicates that the diversity of ground species detected within Playa Sandalo rival other areas under active conservation like Lapa Rios Ecolodge. Historical fragmentation, together with the maintenance of forest cover in isolated conditions, are potentially responsible for the species composition observed within Playa Sandalo; facilitating the development of a prey-predator system including ocelots, medium-size mammals, and birds at the top of the trophic chain. The high diversity of both habitat and vertebrates, its prime location and cultural value, as well as its unique marine importance represent the ideal conditions for conservation. Conservation of Playa Sandalo, and other small tropical forest remnants, might represent the only management option for wildlife conservation within ever growing human-dominated landscapes.
Asunto(s)
Animales Salvajes/fisiología , Conservación de los Recursos Naturales , Animales , Biodiversidad , Costa Rica , Ecosistema , Humanos , IslasRESUMEN
To date, the forcipules have played almost no role in determining the systematics of scutigeromorph centipedes though in his 1974 review of taxonomic characters Markus Würmli suggested some potentially informative variation might be found in these structures. Geometric morphometric analyses were used to evaluate Würmli's suggestion, specifically to determine whether the shape of the forcipular coxa contains information useful for diagnosing species. The geometry of the coxae of eight species from the genera Sphendononema, Scutigera, Dendrothereua, Thereuonema, Thereuopoda, Thereuopodina, Allothereua and Parascutigera was characterised using a combination of landmark- and semi-landmark-based sampling methods to summarize group-specific morphological variation. Canonical variates analysis of shape data characterizing the forcipular coxae indicates that these structures differ significantly between taxa at various systematic levels. Models calculated for the canonical variates space facilitate identification of the main shape differences between genera, including overall length/width, curvature of the external coxal margin, and the extent to which the coxofemoral condyle projects laterally. Jackknifed discriminant function analysis demonstrates that forcipular coxal training-set specimens were assigned to correct species in 61% of cases on average, the most accurate assignments being those of Parascutigera (Parascutigera guttata) and Thereuonema (Thereuonema microstoma). The geographically widespread species Thereuopoda longicornis, Sphendononema guildingii, Scutigera coleoptrata, and Dendrothereua linceci exhibit the least diagnostic coxae in our dataset. Thereuopoda longicornis populations sampled from different parts of East and Southeast Asia were significantly discriminated from each other, suggesting that, in this case, extensive synonymy may be obscuring diagnosable inter-species coxal shape differences.