Road effects on abundance and fitness of Galápagos lava lizards (Microlophus albemarlensis)

Vehicle collisions with wildlife have the potential to negatively impact species everywhere roads divide natural habitats; this is especially true in areas where roads are a recent addition to the landscape (e.g., in the last decade) and/or where expansion of a road network is underway. This study addresses the impact of traffic fatalities on lava lizards, Microlophus albemarlensis, on the island of Santa Cruz, Galápagos. The main road bisecting the island north to south was added to the island beginning in 1974 but not fully paved until 2000. We assessed impacts occurring due to traffic and vehicle speeds on the island. This study adds impacts to lizard populations to those conducted on birds on Santa Cruz, providing a means to create multi-species recommendations. To quantify impacts to lizard populations, we assessed lizards on randomly chosen transects perpendicular to the road. We used Poisson regression to analyze those data and found a 30% increase in lizard abundance per 100 m distance from the road across vegetation zones. We compared incidence of prior tail loss of road-killed lizards and live animals to comment on additional energetic costs of occupying near-road territories. Tail condition could not be assessed in some road-killed lizards; among those that we could assess, 29% showed evidence of prior tail loss. That rate declined to apparent baseline conditions of only 1% beyond 200 m from the road. By traveling the length of the 40-km road, we identified hot spots for fatalities of both lizards and birds to provide necessary information for developing management and remediation strategies. We offer guidance on Best Management Practices, such as testing overpasses, fencing and underpasses, which might reduce vehicle impacts to lizards from drivers on the current road. This information is essential because of a planned increase in the Santa Cruz road network in areas where lava lizards are most abundant.     

Has long-term metal exposure induced changes in life history traits and genetic diversity of the enchytraeid worm Cognettia sphagnetorum (Vejd.)?

We studied whether long-term metal exposure has affected life history traits, population growth patterns and genetic diversity of the asexual enchytraeid worm Cognettia sphagnetorum (Vejd.). Enchytraeids from metal contaminated and uncontaminated forest soil were compared by growing them individually in the laboratory and by following their population development in patchily Cu contaminated microcosms. Genetic differences between the two native populations were studied using allozyme electrophoresis. Individuals from the contaminated site had slower growth rate and they produced fewer fragments of larger size when compared to individuals from the uncontaminated site. In patchily Cu contaminated microcosms, C. sphagnetorum from the contaminated site had a slower population growth rate. Most alleles were shared by the two native populations, but there was greater diversity and more unique genotypes in the population living in the uncontaminated site. Overall, long-term exposure to metals has induced only slight changes in life history properties and clonal diversity of C. sphagnetorum.