Northern Goshawk Habitat: an Intersection of Science,Management, and Conservation

Abstract: We responded to the claim by Greenwald et al. (2005) that the management recommendations for the northern goshawk in the Southwestern United States (MRNG; Reynolds et al. 1992), a food web-based conservation plan that incorporated both northern goshawk (Accipiter gentilis) and multiple prey habitats, may be inadequate to protect goshawks. Greenwald et al. (2005) based this claim on their review of 12 telemetry studies of goshawk habitat selection and 5 nontelemetry studies of the effects of vegetation structure at the home range scale on goshawk nest occupancy and reproduction that appeared after the 1992 publication of the MRNG. Greenwald et al. (2005) summarized their review as showing that 1) goshawks were habitat specialists limited to forests with mature and old-growth structures including large trees, high canopy cover, multiple canopy layering, and abundant woody debris; 2) habitats were not selected on the basis of prey abundance and, therefore, managing for prey habitats diluted goshawk habitats; and 3) selection for openings, edges, and habitat diversity was inconclusive. Our review found that when the studies' respective authors pooled their radiotagged goshawks there were weak to strong selections for old forest structures. However, the studies also documented extensive variation in use of vegetation types and structures by individual goshawks; some avoided openings, edges, young forests, and old forests, whereas others selected for these characteristics. Additionally, by virtue of their wide geographic distribution, the studies showed that the focal populations themselves occurred in a variety of forest types, some with large structural differences. We found no evidence in Greenwald's et al. (2005) review that the MRNG are inadequate to protect goshawks. Rather, the studies reviewed by Greenwald et al. (2005), as well as many studies they missed, supported the MRNG. The suggestion of inadequacy by Greenwald et al. (2005) appeared rooted in misunderstandings of goshawk habitats described in the MRNG, a discounting of the extent of variation in vegetation structural and seral stages used by goshawks, a limited understanding of the extent to which prey limits goshawks, a failure to recognize the dynamic nature of forests, and an incomplete review of the literature. We believe the MRNG are adequate because they maximize the sustainable amount of mature and old forests in goshawk home ranges and specify the kinds and intermixtures of prey habitats within home ranges. Implementation of MRNG should reduce the likelihood that the availability of vegetation structures suited to goshawk nesting and foraging, as well as abundance and availability of prey, will limit goshawk nest occupancy and reproduction.     

Long term oviposition preference and larval performance of Schizomyia macrocapillata (Diptera: Cecidomyiidae) on larger shoots of its host plant Bauhinia brevipes (Fabaceae)

The Plant Vigor Hypothesis (PVH) proposes that natural selection on female oviposition choice results from higher fitness of larvae on more vigorous and larger plant modules. For six consecutive years we tested the PVH predictions by investigating the effect of shoot size of Bauhinia brevipes (Fabaceae) on the oviposition preference and offspring survival of the gall-midge Schizomyia macrocapillata (Diptera: Cecidomyiidae). Additionally, we analyzed the effects of bottom-up and top-down mortality forces on the system. The hypersensitive reaction (bottom-up effect) accounted for more than 90% larval mortality of S. macrocapillata, making available few galls to be found and killed by natural enemies (top-down effect). Smaller shoots were always more abundant while longer shoots were rare. Nevertheless, the percent number of galls induced by S. macrocapillata was up to 10-fold greater on the largest shoots, corroborating the preference prediction of the PVH. Schizomyia macrocapillata should use over-exploit larger shoots to maximize the preference for, and consequently increase the performance on these shoots. Our results partially support the performance prediction of the PVH: (1) the observed survival was higher than expected on longer shoots, and (2) the ratio of survival per shoot was positively related with shoot length only in 2 years. Thus, we found a link between female preference and larval performance on large-sized shoots, at least in some years. The gall-midge attack pattern in this study might be an evolved response to maximize the female preference and increased larval performance on longer shoots of the host plant.     

雷公藤次生代谢产物雷公藤红素含量与环境因子相关性分析

采用多元逐步回归分析对分布于浙江、福建、湖南、湖北和贵州5个省内6类不同居群药用植物雷公藤（Tripterygium wilfordil）的160株个体进行了雷公藤红素含量和环境因子的相关性分析。结果表明,在空间分布上,各居群间的雷公藤红素含量差异较大,其中湖南黄岩居群雷公藤红素含量最高,为1．0585×10^-2g·g^-1,贵州雷山和福建泰宁居群最低,分别为4．9889×10^-3g·g^-1和4．9887×10^-3g·g^-1;而在居群内的雷公藤红素含量相对一致,基本呈正态分布。实验结果表明,雷公藤中雷公藤红素的积累在很大程度上受环境因子的影响。进一步利用SPSS软件对各个环境因子作逐步回归分析,表明年均日照时长（X）、年均降雨量（X2）和土壤含氮量（蚝）是影响雷公藤中雷公藤红素含量（Ⅵ的主导因子,且各因素均与雷公藤红素含量呈负相关。经检验,回归方程为Y=19．308-0．01X1-0．02X2—0．062X5,雅达到0．917,F检验回归方程的线性关系显著。研究结果表明,环境因子,特别是日照、水分和土壤含氮量能够影响雷公藤中雷公藤红素的含量。该文还对提高雷公藤中药用成分雷公藤红素含量的研究策略进行了讨论。     

甲烷氧化细菌氧化活性影响因素的研究

分别对土壤含水量、温度、施肥措施、土壤中CO_2和O_2含量等几个影响甲烷氧化细菌氧化活性的因素作一综述,分析其原因,为今后进一步研究奠定基础。     

Superfamily of plant monomeric GTP-binding proteins: 2. Rab proteins are the regulators of vesicles trafficking and plant responses to stresses

In plants, Rab proteins represent the largest family of monomeric GTP-binding proteins (mG-proteins). As distinct from animal cells comprising 40 subfamilies of Rab proteins, which are the key regulators of intracellular vesicular transport, numerous Rab proteins in Arabidopsis and other plant species could be grouped in only eight subfamilies on the basis of their functional properties. The available data concerning the involvement of these mG-proteins in the control of vesicle trafficking agree generally with the paradigms accepted for other eukaryotes. On the other hand, these proteins play an important role in plant responses to abiotic and biotic factors, indicating specific for plants functions of Rab proteins.     

Expression of the paired box domain Pax7 protein in myogenic cells isolated from the porcine semitendinosus muscle after birth

The paired box domain gene Pax7 plays a pivotal role in satellite cell physiology and may represent one of the candidate genes influencing the dynamic stages of early post-natal growth observed in pig. Quiescent satellite cells express Pax7 and, when activated, they co-express the myogenic bHLH protein MyoD. The aims of this study were to investigate, by immunohistochemistry, the putative differential expression of Pax7 and to ascertain the amount of activated satellite cells (Pax7(+)/MyoD(+)) in myogenic cells isolated at different post-natal time points and in adults. Our results indicate that Pax7(+) cells represent between 10 and 15% of the whole myogenic cell population found at birth indicating that these cells provide a modest contribution to the development of new fibres. The number of activated satellite cells (Pax7(+)/MyoD(+)) was scarce after birth but it was higher respect to adults. An interesting result was that at 1 month after birth the number of Pax7(+) cells had increased within the pool of myogenic cells with respect to myogenic cells extracted at birth. We speculate that Pax7 might be one of the molecules involved in controlling the proliferation/differentiation ratio in the pool of satellite cells present in post-natal porcine skeletal muscles.     

Expression of FGF2 and TGFalpha and testis morphology during testicular hypertrophy subsequent to hemicastration in the neonatal boar

The objective was to ascertain fibroblast growth factor-2 (FGF2), epidermal growth factor (EGF), and transforming growth factor-alpha (TGFalpha) mRNA expression and testis morphology during accelerated testicular growth after hemicastration in the neonatal boar. On Day 10 after birth (Day 0), boars were assigned to control (n = 28), no treatment; hemicastrated (n = 28), left testis removed. The right testis in both groups (n = 7) was removed on Days 5, 10, 15, and 20. Expression of mRNA for FGF2, EGF, and TGFalpha was determined by qRT-PCR using TaqMan. Testicular morphology was determined on Day 15. On Day 10, hemicastrated boars had a greater (P = 0.01) testis weight (6.2 +/- 0.8 g; mean +/- SEM) than controls (4.3 +/- 0.4 g) and on Day 15 testis weight in hemicastrated boars (8.8 +/- 0.8 g) was twice (P < 0.01) that of control boars (4.2 +/- 0.3 g). Seminiferous tubule volume was approximately doubled in hemicastrated boars (P < 0.01) and was associated with an increase (P < 0.01) in Sertoli cell number. Interstitial compartment volume was greater (P < 0.01) in hemicastrated boars. Leydig cell numbers were similar (P = 0.14) but volume was greater (P < 0.01) for hemicastrates. There were no differences (P > 0.05) between control and hemicastrated boars in TGFalpha or FGF2 expression on Day 5 or Day 10, and EGF was not detected. It was concluded that upregulation of TGFalpha or FGF2 expression is not a pre-requisite for enhanced testicular growth and increased Sertoli cell proliferation that occurs subsequent to hemicastration in the neonatal boar.     

Low levels of quantitative and molecular genetic differentiation among natural populations of Medicago ciliaris Kroch. (Fabaceae) of different Tunisian eco-geographical origin

In this paper, we analyze the genetic variability in four Tunisian natural populations of Medicago ciliaris using 19 quantitative traits and six polymorphic microsatellite loci. We investigated the amplification transferability of 30 microsatellites developed in the model legume M. truncatula to M. ciliaris. Results revealed that about 56.66% of analyzed markers are valuable genetic markers for M. ciliaris. The most genetic diversity at quantitative traits and microsatellite loci was found to occur within populations (>80%). Low differentiations among populations at quantitative traits Q _ST  = 0.146 and molecular markers F _ST  = 0.18 were found. The majority of measured traits exhibited no significant difference in the level of Q _ST and F _ST . Furthermore, significant correlations established between these traits and eco-geographical factors suggested that natural selection should be invoked to explain the level of phenotypic divergence among populations rather than drift. There was no significant correlation between population differentiation at quantitative traits and molecular markers. Significant spatial genetic structure consistent with models of isolation by distance was detected within all studied populations. The site-of-origin environmental factors explain about 9.07% of total phenotypic genetic variation among populations. The eco-geographical factors that influence more the variation of measured traits among populations are the soil texture and altitude. Nevertheless, there were no consistent pattern of associations between gene diversity (He) and environmental factors.     

N-terminal pro B-type natriuretic peptide levels predict newly detected atrial fibrillation in a population-based cohort

Background B-type natriuretic peptide (BNP) is secreted from cardiomyocytes and may reflect haemodynamic abnormalities predisposing to atrial fibrillation (AF). We aimed to investigate whether N-terminal pro BNP (NT-proBNP) is associated with newly detected AF in subjects obtained from the general population. Methods From the PREVEND programme (n=8592), we selected all subjects with an available baseline and four-year electrocardiogram and NTproBNP levels at baseline. We excluded subjects with AF at baseline and subjects with a serum creatinine >2.0 mg/dl. Results In total, 6494 subjects were eligible for the prospective analysis (aged 49±12 years, 49.7% men). At four years, AF was detected in 41 (0.6%) subjects. Median NT-proBNP levels at baseline in subjects with newly detected AF after four years was 62.2 (22.6 to 208.5) pg/ml as compared with 35.7 (15.9 to 68.7) pg/ml in those with sinus rhythm (p=0.001). Each 1 standard deviation increment in natural log transformed NT-proBNP was associated with a 54% (5% to 126%, p=0.028) increase in risk for AF after adjustment for other risk factors predisposing to AF. NT-proBNP levels above the sex-specific 80th percentile (97 pg/ml in women and 60 pg/ml in men) were associated with a multivariate odds ratio of 2.65 (1.22 to 5.76, p=0.01) for the occurrence of AF. Conclusion Plasma levels of NT-proBNP predict newly detected AF in subjects obtained from the general population independent of cardiovascular risk factors predisposing to AF. (Neth Heart J 2008;16:73-8.)