Techno-Economical and Ecological Potential of Electric Scooters: A Life Cycle Analysis

In Germany, mobility is currently in a state of flux. Since June 2019, electric kick scooters (e-scooters) have been permitted on the roads, and this market is booming. This study employs a user survey to generate new data, supplemented by expert interviews to determine whether such e-scooters are a climate-friendly means of transport. The environmental impacts are quantified using a life cycle assessment. This results in a very accurate picture of e-scooters in Germany. The global warming potential of an e-scooter calculated in this study is 165 g CO2-eq./km, mostly due to material and production (that together account for 73% of the impact). By switching to e-scooters where the battery is swapped, the global warming potential can be reduced by 12%. The lowest value of 46 g CO2-eq./km is reached if all possibilities are exploited and the life span of e-scooters is increased to 15 months. Comparing these emissions with those of the replaced modal split, e-scooters are at best 8% above the modal split value of 39 g CO2-eq./km

Variation in Vital-rate Sensitivity Between Populations of Texas Horned Lizards

Demographic studies of imperiled populations can aid managers in planning conservation actions. However, applicability of findings for a single population across a species’ range is sometimes questionable. We conducted long-term studies (8 and 9 years, respectively) of 2 populations of the lizard Phrynosoma cornutum separated by 1000 km within the historical distribution of the species. The sites were a 15-ha urban wildlife reserve on Tinker Air Force Base (TAFB) in central Oklahoma and a 6000-ha wildland site in southern Texas, the Chaparral Wildlife Management Area (CWMA). We predicted a trade-off between the effect of adult survival and fecundity on population growth rate (λ), leading to population-specific contributions of individual vital rates to λ and individualized strategies for conservation and management of this taxon. The CWMA population had lower adult survival and higher fecundity than TAFB. As predicted, there was a trade-off in the effects of adult survival and fecundity on λ between the two sites; fecundity affected λ more at CWMA than at TAFB. However, adult survival had the smallest effect on λ in both populations. We found that recruitment in P. cornutum most affected λ at both sites, with hatchling survival having the strongest influence on λ. Management strategies focusing on hatchling survival would strongly benefit both populations. As a consequence, within the constraint of the need to more accurately estimate hatchling survival, managers across the range of species such as P. cornutum could adopt similar management priorities with respect to stage classes, despite intra-population differences in population vital rates

Demography of North American Tortoises

Life-history traits include those characters ultimately influencing the growth and persistence of populations in the face of environmental change. In general, the traits of males, as well as the sex ratios of populations, may not be as important as the traits of females to population growth in North American tortoises, because females of most tortoise species are known to store sperm. The overriding importance of female traits may be especially strong when sperm can be stored for multiple years with little loss of ability to fertilize eggs, which has been demonstrated for Gopherus agassizii (Palmer et al. 1998). Females should be able to produce eggs even when they mate infrequently, so traits of females may be key to predicting population growth. The important female traits include age of first reproduction, clutch size, number of clutches produced per year, and age-specific survivorship. Environmental factors influence all of these traits. Here, we present an outline of the demographic data available for females of the species of North American tortoises. We also present comparative data for males. The type and extent of data vary among species, often reflecting the biases of the researchers gathering the data. Geographical and environmental variation in the data are illustrated, but the actual extent of such variation probably is greater than reported. As demography depends on many rates, such as birth rate and growth rate, information from other chapters (e.g., chapters 7 and 13) can supplement the information presented in this chapter