Carbon sequestration value of biosolids applied to soil: A global meta-analysis.

Biosolids produced at wastewater treatment facilities are extensively used in agricultural land and degraded mine sites to improve soil health and soil organic carbon (SOC) stocks. Many studies have reported increases in SOC due to application of biosolids to such sites. However, lack of a comprehensive quantification on overall trends and changes of magnitude in SOC remains. Here, we performed a meta-analysis to identify drivers with a relationship with SOC stocks. A meta-regression of 297 treatments found four variables with a relationship with SOC stocks: cumulative biosolids carbon (C) input rate, time after application, soil depth and type of biosolids. The cumulative biosolids C input rate was the most influencing driver. The highest mean difference for SOC% of 3.3 was observed at 0-15 cm soil depth for a cumulative C input of 100 Mg ha-1 at one year after biosolids application. Although years after biosolids application demonstrated a negative relationship with SOC stocks, mineralization of C in biosolids-applied soils is slow, as indicated with the SOC% decrease from 4.6 to 2.8 at 0-15 cm soil depth over five years of 100 Mg ha-1 biosolids C input. Soil depth illustrated a strong negative effect with SOC stocks decreasing by 2.7% at 0-15 cm soil depth at a cumulative biosolids C input of 100 Mg ha-1 over a year. Overall, our model estimated an effect of 2.8 SOC% change, indicating the application of biosolids as a viable strategy for soil C sequestration on a global scale.

Diet selection in the Coyote Canis latrans.

The Coyote (Canis latrans) is one of the most studied species in North America with at least 445 papers on its diet alone. While this research has yielded excellent reviews of what coyotes eat, it has been inadequate to draw deeper conclusions because no synthesis to date has considered prey availability. We accounted for prey availability by investigating the prey selection of coyotes across its distribution using the traditional Jacobs' index method, as well as the new iterative preference averaging (IPA) method on scats and biomass. We found that coyotes selected for Dall's Sheep (Ovis dalli), White-tailed Deer (Odocoileus virginianus), Eastern Cottontail Rabbit (Sylvilagus floridanus), and California Vole (Microtus californicus), which yielded a predator-to-preferred prey mass ratio of 1:2. We also found that coyotes avoided preying on other small mammals, including carnivorans and arboreal species. There was strong concordance between the traditional and IPA method on scats, but this pattern was weakened when biomass was considered. General linear models revealed that coyotes preferred to prey upon larger species that were riskier to hunt, reflecting their ability to hunt in groups, and were least likely to hunt solitary species. Coyotes increasingly selected Mule Deer (O. hemionus) and Snowshoe Hare (Lepus americanus) at higher latitudes, whereas Black-tailed Jackrabbit (L. californicus) were increasingly selected toward the tropics. Mule Deer were increasingly selected at higher coyote densities, while Black-tailed Jackrabbit were increasingly avoided at higher coyote densities. Coyote predation could constrain the realized niche of prey species at the distributional limits of the predator through their increased efficiency of predation reflected in increased prey selection values. These results are integral to improved understandings of Coyote ecology and can inform predictive analyses allowing for spatial variation, which ultimately will lead to better understandings about the ecological role of the coyote across different ecosystems.

El coyote (Canis latrans) es una de las especies más estudiadas en América del Norte con al menos 445 artículos solo sobre su dieta. Si bien esta investigación ha producido excelentes revisiones de lo que comen los coyotes, no ha sido adecuada para sacar conclusiones más profundas porque ninguna síntesis hasta la fecha ha considerado la disponibilidad de presas. Tomamos en cuenta la disponibilidad de presas al investigar la selección de presas de los coyotes a lo largo de la distribución de la especie utilizando el método tradicional del índice de Jacobs, así como el nuevo método iterativo de promedio de preferencia sobre excrementos y biomasa. Descubrimos que los coyotes seleccionados para la oveja de Dall (Ovis dalli), el venado de cola blanca (Odocoileus virginianus), los conejos de rabo blanco del este (Sylvilagus floridanus) y los campañoles de California (Microtus californicus), produjeron una proporción de masa de depredador a presa preferida de 1:2. También encontramos que los coyotes evitaban depredar a otros mamíferos pequeños, incluidos los carnívoros y las especies arbóreas. Hubo una fuerte concordancia entre el método de promedio de preferencia tradicional e iterativo en los excrementos, pero este patrón se debilitó cuando se consideró la biomasa. Los modelos lineales generales revelaron que los coyotes preferían cazar especies más grandes que eran más riesgosas de cazar, lo que reflejaba su capacidad para cazar en grupos, y era menos probable que cazaran especies solitarias. Los coyotes seleccionaron cada vez más al venado bura (O. hemionus) y la liebre con raquetas de nieve (Lepus americanus) en latitudes más altas, mientras que la liebre de cola negra (L. californicus) fue seleccionada cada vez más hacia los trópicos. El venado bura se seleccionaba cada vez más en densidades más altas de coyotes, mientras que la liebre de cola negra se evitaba cada vez más en densidades más altas de coyotes. La depredación de los coyotes podría restringir el nicho realizado de las especies de presa en los límites de distribución de las especies de depredadores a través de su mayor eficiencia de depredación reflejada en mayores valores de selección de presas. Estos resultados son parte integral de una mejor comprensión de la ecología del coyote y pueden informar análisis predictivos que permitan la variación espacial, lo que en última instancia conducirá a una mejor comprensión sobre el papel ecológico del coyote en diferentes ecosistemas.

Prepubertal mouse testis growth and maturation and androgen production are acutely sensitive to di-n-butyl phthalate.

Phthalates are plasticizers with widespread industrial, domestic, and medical applications. Epidemiological data indicating increased incidence of testicular dysgenesis in boys exposed to phthalates in utero are reinforced by studies demonstrating that phthalates impair fetal rodent testis development. Because humans are exposed to phthalates continuously from gestation through adulthood, it is imperative to understand what threat phthalates pose at other life stages. To determine the impact during prepuberty, we assessed the consequences of oral administration of 1 to 500 mg di-n-butyl phthalate (DBP)/kg/d in corn oil to wild-type (C57BL/6J) male mice from 4 to 14 days of age. Dose-dependent effects on testis growth correlated with reduced Sertoli cell proliferation. Histological and immunohistochemical analyses identified delayed spermatogenesis and impaired Sertoli cell maturation after exposure to 10 to 500 mg DBP/kg/d. Interference with the hypothalamic-pituitary-gonadal axis was indicated in mice fed 500 mg DBP/kg/d, which had elevated circulating inhibin but no change in serum FSH. Increased immunohistochemical staining for inhibin-α was apparent at doses of 10 to 500 mg DBP/kg/d. Serum testosterone and testicular androgen activity were lower in the 500 mg DBP/kg/d group; however, reduced anogenital distance in all DBP-treated mice suggested impaired androgen action at earlier time points. Long-term effects were evident, with smaller anogenital distance and indications of disrupted spermatogenesis in adult mice exposed prepubertally to doses from 1 mg DBP/kg/d. These data demonstrate the acute sensitivity of the prepubertal mouse testis to DBP at doses 50- to 500-fold lower than those used in rat and identify the upregulation of inhibin as a potential mechanism of DBP action.