Leiocephalus semilineatus

Number of Pages: 2Integrative BiologyGeological Science

Bioclimatic Implications and Distribution Patterns of the Modern Ground Beetle Fauna (Insecta: Coleoptera: Carabidae) of the Arctic Slope of Alaska, U.S.A.

Some 56 species of Carabidae have been previously reported on the Arctic Slope of Alaska; of these, only nine have been found at coastal sites in the region. Though for some taxa (e.g., most species of Bembidion) this may reflect a lack of suitable habitat in the coastal environment, for most others it probably reflects the summer temperature differences between the relatively cool coastal areas (mean July temp [mJt] of ca. 4°C) and warmer interior sites (mJt of ca. 9-10°C). The boundary between the relatively species-rich interior fauna and the more depauperate coastal fauna is probably also approximated by the inland limit of incursions of cool summer coastal fogs, which coincides with a sharp vegetational boundary. Additional systematic collecting of specimens and a coordinated effort to gather climate data will be needed to delimit distributional limits more closely and to provide background data for both modern environmental monitoring and paleoenvironmental reconstructions.On a déjà rapporté la présence d'environ 56 espèces de carabidés sur la pente arctique de l'Alaska; de ces espèces, seulement neuf se trouvaient dans des zones côtières de la région. Bien que pour certains taxons (p. ex., la plupart des espèces Bembidion), ce fait pourrait témoigner du manque d'un habitat propice dans l'environnement côtier, pour la plupart des taxons, il est un reflet des différences de température estivale entre les zones littorales relativement fraîches (moyenne de la température en juillet [mtj] d'environ 4°C) et des sites plus chauds de l'intérieur des terres (mtj d'environ 9 à 10°C). La délimitation entre la faune de l'intérieur relativement riche en espèces et la faune côtière plus pauvre est probablement aussi définie par la limite, à l'intérieur des terres, des intrusions estivales du brouillard côtier frais, qui coïncident avec une démarcation très nette de la végétation. D'autres collectes systématiques de spécimens et un effort coordonné en vue de recueillir des données climatiques seront nécessaires pour établir des limites de distribution plus précises et pour fournir des données de base en vue du contrôle de l'environnement contemporain comme de la reconstitution paléoenvironnementale

NATURAL HISTORY OF LEIOCEPHALUS SEMILINEATUS IN ASSOCIATION WITH SYMPATRIC LEIOCEPHALUS SCHREIBERSII AND AMEIVA LINEOLATA

We examined diet, habitat use, and behavior (focal animal observations of intraspecific interactions, escape behavior, and activity period) of Leiocephalus semilineatus from near Puerto Alejandro, Provincia de Barahona, República Dominicana, and compared some parameters to similar data collected at a site near Baní, Provincia de Peravia. Leiocephalus semilineatus is found in sympatry in dry scrub forests at both sites with Ameiva lineolata, an active-foraging teiid of approximately the same size, and at the Puerto Alejandro site with a larger congener, L. schreibersii. Leiocephalus semilineatus and L. schreibersii from Puerto Alejandro exhibited sexual size dimorphism, whereas L. semilineatus from the Baní site and A. lineolata did not. Leiocephalus semilineatus spent most of the time motionless; other observed activities were interactions with conspecifics, movement, and feeding. Lizards were active from shortly after sunrise to sundown, although activity peaked in late morning. Mean cloacal temperatures of L. semilineatus did not differ significantly from those of the other two species, but were significantly above ambient temperatures. Reproductive condition of collected specimens was examined and no correlation was found between snout-vent length and egg, follicle, or testis size. Clutch size was 1–2. Diets consisted primarily of invertebrates and did not differ significantly between the three species

A Postglacial Pollen Record from Western Kodiak Island, Alaska

Excavation of organic deposits in a seasonally dry depression atop a moraine crest near the village of Karluk, on the west side of Kodiak Island, has provided a more detailed paleoenvironmental record than hitherto available for this part of the island. Radiocarbon dating indicates that the base of the section is approximately 4260 14C years in age. Seven minor volcanic ashes are recognized prior to the onset of seasonal drying of the basin at about 2330 B.P. A major ash fall (2 cm thick in section) is recorded at about 1625 B.P. The only significant woody taxon indicated in the pollen record is alder (Alnus); all other important taxa are herbaceous. This vegetation record indicates alders and ferns dominated the landscape immediately following substrate stabilization, which apparently was delayed in this area until well into the Holocene. Alder became relatively less important as soils matured and other taxa (mostly grasses) invaded. The overall record is one of vegetational and climatic stability since landscape stabilization in this area. Volcanic ashfalls have apparently had no significant long-term impact on the vegetation at the site.Key words: Alaska, Holocene, Karluk, Kodiak Island, Quaternary, geology, glaciation, paleoenvironments, palynology, radiocarbon dating, tephraMots clés: Alaska, holocène, Karluk, île Kodiak, quaternaire, géologie, glaciation, paléoenvironnements, palynologie, datation au radiocarbone, cendres volcanique