RESUMEN
Research on thermal receipts has previously focused on the toxic effects of dermal exposure from the most publicized developers (e.g., bisphenol A (BPA) and bisphenol S (BPS)), while no studies have reported on the other solvent-extractable compounds therein. Diphenyl sulfone (DPS) is a sensitizer added to thermal receipts, but little is known about DPS concentrations in receipts or potential toxicity. Here, we quantified BPA, BPS, and DPS concentrations and tentatively identified the solvent-extractable compounds of thermal receipts collected from three South Dakota (USA) cities during 2016-2017. An immortalized chicken hepatic cell line, cultured as 3D spheroids, was used to screen effects of DPS, BPS, and 17ß estradiol (E2; 0.1-1000 µM) on cell viability and gene expression changes. These chemicals elicited limited cytotoxicity with LC50 values ranging from 113 to 143 µM, and induced dysregulation in genes associated with lipid and bile acid homeostasis. Taken together, this study generated novel information on solvent-extractable chemicals from thermal receipts and toxicity data for DPS.
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Compuestos de Bencidrilo , Compuestos de Bifenilo , Fenoles , Sulfonas , Sulfonas/toxicidad , Compuestos de Bencidrilo/toxicidad , SolventesRESUMEN
Intactness is a commonly used measure of ecological integrity, especially when evaluating conservation status at the landscape scale. We argue that in the large and relatively unfragmented landscapes of the Arctic and sub-Arctic, intactness provides only partial insight for managers charged with maintaining ecological integrity. A recent landscape assessment suggests that 95% of Alaska shows no measured direct or indirect impacts of human development on the landscape. However, the current exceptionally high levels of intactness in Alaska, and throughout the Arctic and sub-Arctic, do not adequately reflect impacts to the region's ecological integrity caused by indirect stressors, such as a rapidly changing climate and the subsequent loss of the cryosphere. Thus, it can be difficult to measure, and manage, some of the conservation challenges presented by the ecological context of these systems. The dominant drivers of change, and their associated ecological and socioeconomic impacts, vary as systems decline in ecological integrity from very high to high, and to intermediate levels, but this is not well understood in the literature. Arctic and sub-Arctic systems, as well as other large intact areas, provide unique opportunities for conservation planning, but require tools and approaches appropriate to unfragmented landscapes undergoing rapid climate-driven ecological transformation. We conclude with possible directions for developing more appropriate metrics for measuring ecological integrity in these systems.
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Cambio Climático , Ecosistema , Humanos , Regiones Árticas , Clima , AlaskaRESUMEN
The ability to quantify spatial patterns and detect change in terrestrial vegetation across large landscapes depends on linking ground-based measurements of vegetation to remotely sensed data. Unlike non-overlapping categorical vegetation types (i.e., typical vegetation and land cover maps), species-level gradients of foliar cover are consistent with the ecological theories of individualistic response of species and niche space. We collected foliar cover data for vascular plant, bryophyte, and lichen species and 17 environmental variables in the Arctic Coastal Plain and Brooks Foothills of Alaska from 2012 to 2017. We integrated these data into a standardized database with 13 additional vegetation survey and monitoring data sets in northern Alaska collected from 1998 to 2017. To map the patterns of foliar cover for six dominant and widespread vascular plant species in arctic Alaska, we statistically associated ground-based measurements of species distribution and abundance to environmental and multi-season spectral covariates using a Bayesian statistical learning approach. For five of the six modeled species, our models predicted 36% to 65% of the observed species-level variation in foliar cover. Overall, our continuous foliar cover maps predicted more of the observed spatial heterogeneity in species distribution and abundance than an existing categorical vegetation map. Mapping continuous foliar cover at the species level also revealed ecological patterns obscured by aggregation in existing plant functional type approaches. Species-level analysis of vegetation patterns enables quantifying and monitoring landscape-level changes in species, vegetation communities, and wildlife habitat independently of subjective categorical vegetation types and facilitates integrating spatial patterns across multiple ecological scales. The novel species-level foliar cover mapping approach described here provides spatial information about the functional role of plant species in vegetation communities and wildlife habitat that are not available in categorical vegetation maps or quantitative maps of broadly defined vegetation aggregates.