Effects of forest management on vertebrates: synthesizing two decades of data from hardwood forests in Missouri, USA.

Modern forest management seeks to balance multiple social, economic, and ecological goals. Different management approaches create different types of disturbances in a forest ecosystem and thus also differ in their impacts on plants, animals, and insects. Understanding these impacts is important for conservation of forest ecosystem function, but challenging due to the large spatial and temporal scale over which management occurs. Most past research has focused on relatively small areas, short time scales, and/or a small number of species. To address this, we examined the effects of two common silvicultural systems (even and uneven aged) on abundance and richness of three vertebrate taxa (birds, small mammals, and herpetofauna) over a two-decade period in a temperate hardwood forest in Missouri, USA. The two systems removed a similar amount of biomass overall, but differed in the intensity, number, and configuration of harvests applied. We found that vertebrate population responses varied by taxa, occurred at multiple spatial scales, and were concentrated in the period following the first harvest entry. Birds generally had the largest changes in relative abundance, both positive and negative, following management. Small mammals and reptiles had smaller, but generally positive, responses; amphibians were mixed. Bird species tended to respond in the same way to both silvicultural systems, while small mammals and herpetofauna did not respond consistently. Thus, for birds, the total amount of harvest disturbance across the landscape drives population responses, while for others the size and configuration of individual harvests is likely more important. Synthesizing results across the vertebrate community at large spatial and temporal scales allows managers to better understand trade-offs when making decisions that will affect wildlife in contrasting ways.

Atenolol pharmacokinetics and excretion in breast milk during the first 6 to 8 months postpartum.

The objectives were to evaluate the time course for atenolol pharmacokinetics in lactating women postpartum and to quantify atenolol plasma concentrations in the women's 3- to 4-month-old nursing infants. Data were collected during 1 dosing interval from lactating women treated with atenolol for therapeutic reasons, at 2 to 4 weeks (n = 32), 3 to 4 months (n = 22), and 6 to 8 months (n = 17) postpartum. A single blood sample was collected from 15 nursing infants (3-4 months of age) of the mothers participating in the study. At 2 to 4 weeks, 3 to 4 months, and 6 to 8 months postpartum, atenolol infant doses, relative to the mother's weight-adjusted dose, were 14.6% ± 7.6%, 8.3% ± 5.2% and 5.9% ± 2.9%, respectively. Over this time, maternal atenolol pharmacokinetics did not change to a clinically significant extent. Atenolol concentrations were below assay quantification limits (<10 ng/mL) in the plasma of all 3- to 4-month-old nursing infants studied. These findings support the careful use of atenolol during breastfeeding, because in the vast majority of healthy, term infants, atenolol concentrations will be too low to be clinically relevant. Premature infants and those with kidney disease require further study. Infant exposure depends on maternal dose and decreases during the first 6 to 8 months postpartum.