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1.  Effects of Management Intervention on Post-Disturbance Community Composition: An Experimental Analysis Using Bayesian Hierarchical Models 
PLoS ONE  2013;8(3):e59900.
As human demand for ecosystem products increases, management intervention may become more frequent after environmental disturbances. Evaluations of ecological responses to cumulative effects of management interventions and natural disturbances provide critical decision-support tools for managers who strive to balance environmental conservation and economic development. We conducted an experiment to evaluate the effects of salvage logging on avian community composition in lodgepole pine (Pinus contorta) forests affected by beetle outbreaks in Oregon, USA, 1996–1998. Treatments consisted of the removal of lodgepole pine snags only, and live trees were not harvested. We used a Bayesian hierarchical model to quantify occupancy dynamics for 27 breeding species, while accounting for variation in the detection process. We examined how magnitude and precision of treatment effects varied when incorporating prior information from a separate intervention study that occurred in a similar ecological system. Regardless of which prior we evaluated, we found no evidence that the harvest treatment had a negative impact on species richness, with an estimated average of 0.2–2.2 more species in harvested stands than unharvested stands. Estimated average similarity between control and treatment stands ranged from 0.82–0.87 (1 indicating complete similarity between a pair of stands) and suggested that treatment stands did not contain novel assemblies of species responding to the harvesting prescription. Estimated treatment effects were positive for twenty-four (90%) of the species, although the credible intervals contained 0 in all cases. These results suggest that, unlike most post-fire salvage logging prescriptions, selective harvesting after beetle outbreaks may meet multiple management objectives, including the maintenance of avian community richness comparable to what is found in unharvested stands. Our results provide managers with prescription alternatives to respond to severe beetle outbreaks that continue to occur across extensive portions of the dry forests of western North America.
doi:10.1371/journal.pone.0059900
PMCID: PMC3606292  PMID: 23533659
2.  Avian Species Richness in Relation to Intensive Forest Management Practices in Early Seral Tree Plantations 
PLoS ONE  2012;7(8):e43290.
Background
Managers of landscapes dedicated to forest commodity production require information about how practices influence biological diversity. Individual species and communities may be threatened if management practices truncate or simplify forest age classes that are essential for reproduction and survival. For instance, the degradation and loss of complex diverse forest in young age classes have been associated with declines in forest-associated Neotropical migrant bird populations in the Pacific Northwest, USA. These declines may be exacerbated by intensive forest management practices that reduce hardwood and broadleaf shrub cover in order to promote growth of economically valuable tree species in plantations.
Methodology and Principal Findings
We used a Bayesian hierarchical model to evaluate relationships between avian species richness and vegetation variables that reflect stand management intensity (primarily via herbicide application) on 212 tree plantations in the Coast Range, Oregon, USA. Specifically, we estimated the influence of broadleaf hardwood vegetation cover, which is reduced through herbicide applications, on bird species richness and individual species occupancy. Our model accounted for imperfect detection. We used average predictive comparisons to quantify the degree of association between vegetation variables and species richness. Both conifer and hardwood cover were positively associated with total species richness, suggesting that these components of forest stand composition may be important predictors of alpha diversity. Estimates of species richness were 35–80% lower when imperfect detection was ignored (depending on covariate values), a result that has critical implications for previous efforts that have examined relationships between forest composition and species richness.
Conclusion and Significance
Our results revealed that individual and community responses were positively associated with both conifer and hardwood cover. In our system, patterns of bird community assembly appear to be associated with stand management strategies that retain or increase hardwood vegetation while simultaneously regenerating the conifer cover in commercial tree plantations.
doi:10.1371/journal.pone.0043290
PMCID: PMC3419709  PMID: 22905249
3.  Chemoprevention of dibenzo[a,l]pyrene transplacental carcinogenesis in mice born to mothers administered green tea: primary role of caffeine 
Carcinogenesis  2008;29(8):1581-1586.
Our laboratory recently developed a mouse model of transplacental induction of lymphoma, lung and liver cancer by the polycyclic aromatic hydrocarbon, dibenzo[a,l]pyrene (DBP). Pregnant B6129SF1 females, bred to 129S1/SvIm males, were treated on day 17 of gestation with an oral dose of 15 mg/kg DBP. Beginning on day 0 of gestation, dams were given (ad lib) buffered water, 0.5% green tea, 0.5% decaffeinated green tea, caffeine or epigallocatechin-3-gallate (EGCG) (both at equivalent concentrations found in tea). The concentration of the teas (and corresponding caffeine and EGCG) was increased to 1.0% upon entering the second trimester, 1.5% at onset of the third trimester and continued at 1.5% until pups were weaned at 21 days of age. Offspring were raised with normal drinking water and AIN93G diet. Beginning at 2 months of age, offspring experienced significant mortalities due to an aggressive T-cell lymphoma as seen in our previous studies. Ingestion of caffeinated, but not decaffeinated, green tea provided modest but significant protection (P = 0.03) against mortality. Caffeine provided a more robust (P = 0.006) protection, but EGCG was without effect. Offspring also developed DBP-dependent lung adenomas. All treatments significantly reduced lung tumor multiplicity relative to controls (P < 0.02). EGCG was most effective at decreasing tumor burden (P = 0.005) by on average over 40% compared with controls. Induction of Cytochrome P450 (Cyp)1b1 in maternal liver may reduce bioavailability of DBP to the fetus as a mechanism of chemoprevention. This is the first demonstration that maternal ingestion of green tea, during pregnancy and nursing, provides protection against transplacental carcinogenesis.
doi:10.1093/carcin/bgm237
PMCID: PMC2516488  PMID: 18635525
4.  Fetal Mouse Cyp1b1 and Transplacental Carcinogenesis from Maternal Exposure to Dibenzo[a,l]pyrene 
Dibenzo[a,l]pyrene (DBP) is among the most potent carcinogenic polycyclic aromatic hydrocarbons (PAHs). Previously, we showed that DBP administration to pregnant mice resulted in high mortality of offspring from an aggressive T-cell lymphoma. All mice that survive to 10 months of age exhibit lung tumors with high multiplicity. Recombinant cytochrome P450 (cyp) 1b1 from mice and the homolog 1B1 in humans exhibit high activity toward the metabolic activation of DBP. Targeted disruption of the cyp1b1 gene protects against most DBP-dependent cancers. Mice heterozygous (het) for the disrupted cyp1b1 allele were used to examine the effect of cyp1b1 gene dosage on DBP transplacental carcinogenesis. Dams were treated with 1 or 15 mg/kg of DBP or 50 mg/kg of benzo[a]pyrene (BP). Cyp1b1-null offspring did not develop lymphoma, whereas, wild-type and heterozygous siblings, born to dams given the high dose of DBP, exhibited significant mortalities between 10–30 weeks of age. At 10 months, all groups had lung adenomas or carcinomas (9.5, 40.3, 25.6 and 100% incidences for controls, BP, 1 and 15 mg/kg DBP, respectively). Cyp1b1 status did not alter BP-dependent carcinogenesis. At 1 mg/kg DBP, cyp1b1 status altered the incidence of lung tumors (19.0, 27.8 and 28.6% for nulls, heterozygous and wild-type, respectively). At 15 mg/kg, tumor multiplicities in cyp1b1 wild-type (9.3) and heterozygous (9.5) offspring were nearly twice that of cyp1b1-null siblings (5.0). These data confirm that cyp1b1 bioactivation of DBP occurs in fetal target tissues, following transplacental exposure, with the thymus and lung as primary and secondary targets, respectively.
doi:10.1158/1940-6207.CAPR-07-0004
PMCID: PMC2692138  PMID: 19138945
Cytochrome P4501B1; transplacental cancer; Polycyclic Aromatic Hydrocarbons; Lymphoma; Lung Cancer

Results 1-4 (4)