An Assessment of Road Impacts on Wildlife Populations in U.S. National Parks

Current United States National Park Service (NPS) management is challenged to balance visitor use with the environmental and social consequences of automobile use. Wildlife populations in national parks are increasingly vulnerable to road impacts. Other than isolated reports on the incidence of road-related mortality, there is little knowledge of how roads might affect wildlife populations throughout the national park system. Researchers at the Western Transportation Institute synthesized information obtained from a system-wide survey of resource managers to assess the magnitude of their concerns on the impacts of roads on park wildlife. The results characterize current conditions and help identify wildlife-transportation conflicts. A total of 196 national park management units (NPS units) were contacted and 106 responded to our questionnaire. Park resource managers responded that over half of the NPS units’ existing transportation systems were at or above capacity, with traffic volumes currently high or very high in one quarter of them and traffic expected to increase in the majority of units. Data is not generally collected systematically on road-related mortality to wildlife, yet nearly half of the respondents believed road-caused mortality significantly affected wildlife populations. Over one-half believed habitat fragmentation was affecting wildlife populations. Despite these expressed concerns, only 36% of the NPS units used some form of mitigation method to reduce road impacts on wildlife. Nearly half of the respondents expect that these impacts would only worsen in the next five years. Our results underscore the importance for a more systematic approach to address wildlife-roadway conflicts for a situation that is expected to increase in the next five to ten years.     

Do sex-changing male snails use mate choice to get a jump on their “size advantage”?

Individuals of species that change sex from male to female may gain a “size advantage” from that sex change; that is, as males become larger, they become female, thus increasing their fecundity with their size. However, males could also gain an early and different reproductive size advantage by choosing large females as mates. While male preference for large females has been observed in many dioecious species, we know little about male size preference in sex-changing species. In choice experiments, we examined whether males of two congeneric species of marine sex-changing snails, Crepidula fornicata and C. convexa, chose large females over small ones as partners. We also used choice tests to see whether males of C. fornicata, a species whose members form long-term, multi-animal stacks, would choose two females in a stack over a single female. Surprisingly, males of neither species showed a preference for large females, in spite of the documented fecundity advantage associated with large female-size. Males of C. fornicata chose slightly, but not significantly, more single females than stacks, suggesting that neither number nor size drives mate choice in these animals. Key factors that may influence this lack of size preference include long association time, the likelihood of sperm competition, and the cost of extended mate search; it may also be that sex-change itself, the very factor that creates female-biased sexual size dimorphism in these species, prevents size preference, as males may gain sufficient reproductive advantage from eventually becoming large females themselves to offset any benefit of choosing large females.     

Recovery or decline of the northwestern Black Sea: A societal choice revealed by socio-ecological modelling

During recent decades anthropogenic activities have dramatically impacted the Black Sea ecosystem. High levels of riverine nutrient input during the 1970s and 1980s caused eutrophic conditions including intense algal blooms resulting in hypoxia and the subsequent collapse of benthic habitats on the northwestern shelf. Intense fishing pressure also depleted stocks of many apex predators, contributing to an increase in planktivorous fish that are now the focus of fishing efforts. Additionally, the Black Sea's ecosystem changed even further with the introduction of exotic species. Economic collapse of the surrounding socialist republics in the early 1990s resulted in decreased nutrient loading which has allowed the Black Sea ecosystem to start to recover, but under rapidly changing economic and political conditions, future recovery is uncertain.     

Age-related changes in reproductive effort of male bison

Summary The behavior of male bison during the rut was studied, to test the prediction that reproductive effort should increase with age. Because bull bison do not show parental care, the major component of reproductive effort is competition with other bulls to obtain copulations with estrous females. Data were collected on activity budgets during the pre-rut and rut seasons, on interactions with other bulls, and on proximity to tended females during the rut. Participation in the rut started at ages 5–6. Older bulls showed greater percent time active and less percent time eating than younger bulls. The older bulls also had higher counts of dominance and fight-related interactions and lower counts for behavior associated with submission than did the younger bulls. Risk taken seemed to increase with age since bulls aged 6 to 12 participated more frequently in dangerous activities associated with fighting. Within the 6 to 12 year old group, activity patterns changed little with age. However, from the interaction information, peak ages of 8 to 11 years appeared. For the activities: back up, chase, clash, head nod, jump away, move away, run away, run toward, push heads, dominant, and risk, 11 and 12 year olds more closely resembled younger bulls. This suggests a reproductive effort curve that is flat at zero until about age 6, increases to age 8, flattens out again to around age 10, and then decreases somewhat. Reproductive effort in male bison thus generally conforms with life-history theory predictions.     

Understanding the processes in a historically relevant thermal and mineral spring water by using mixing and inverse geochemical models

Environmental Geochemistry and Health - The thermal mineral water of Peñón de los Baños spa (Mexico City) has been used for over 500 years starting in pre-Hispanic times and...     

Side effects of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> var. kurstaki on the hymenopterous parasitic wasp <Emphasis Type="Italic">Trichogramma chilonis</Emphasis>

Most of the detrimental effects of using conventional insecticides to control crop pests are now well identified and are nowadays major arguments for replacing such compounds by the use of biological control agents. In this respect, the bacterium Bacillus thuringiensis var. kurstaki and Trichogramma (Hymenoptera: Trichogrammatidae) parasitic wasp species are both effective against lepidopterous pests and can actually be used concomitantly. In this work, we studied the potential side effects of B. thuringiensis var. kurstaki on Trichogramma chilonis females. We first evidenced an acute toxicity of B. thuringiensis on T. chilonis. Then, after ingestion of B. thuringiensis at sublethal doses, we focused on life history traits of T. chilonis such as longevity, reproductive success and the time spent on host eggs patches. The reproductive success of T. chilonis was not modified by B. thuringiensis while a significant effect was observed on longevity and the time spent on host eggs patches. The physiological and ecological meanings of the results obtained are discussed.     

Daphne gnidium, a possible native host plant of the European grapevine moth Lobesia botrana, stimulates its oviposition. Is a host shift relevant?

Summary. We tested the hypothesis that Daphne gnidium is an ancestral host plant of Lobesia botrana. To this end, we studied the oviposition response of this moth to various aerial organs of this plant. Our results show that females prefer to lay eggs on daphne berries rather than on grapes (cv. chasselas) and that polar surface extracts of daphne berries and leaves strongly stimulate oviposition in a dosedependant way, whereas flower extracts are weakly stimulant and branch extracts are inactive or deterrent for oviposition. Furthermore, a total extract of daphne berries stimulates oviposition in semi-natural conditions when applied onto fresh grapes. Oviposition stimulants from berries were isolated by HPLC coupled with a dual-choice oviposition bioassay. The ecological value of D. gnidium for L. botrana is discussed and the possible use of oviposition stimulants from daphne, contrasting with the oviposition signal of the cultivated host plant, is proposed in the perspective of developing behavioural manipulation methods such as stimulo-deterrent diversionary strategies compatible with IPM programs.