High ENSO sensitivity in tree rings from a northern population of Polylepis tarapacana in the Peruvian Andes

Polylepis tarapacana is the highest-elevation tree species worldwide growing between 4000 and 5000 m a.s.l. along the South American Altiplano. P. tarapacana is adapted to live in harsh conditions and has been widely used for drought and precipitation tree-ring based reconstructions. Here, we present a 400-year tree-ring width (TRW) chronology located in southern Peru (17ºS; 69ºW) at the northernmost limit of P. tarapacana tree species distribution. The objectives of this study are to assess tree growth sensitivity of a northern P. tarapacana population to (1) precipitation, temperature and El Niño Southern Oscillation (ENSO) variability; (2) to compare its growth variability and ENSO sensitivity with southern P. tarapacana forests. Our results showed that this TRW record is highly sensitive to the prior summer season (Nov-Jan) precipitation (i.e. positive correlation) when the South American Summer Monsoon (SASM) reaches its maximum intensity in this region. We also found a positive relationship with current year temperature that suggests that radial growth may be enhanced by warm, less cloudy, conditions during the year of formation. A strong positive relationship was found between el Niño 3.4 and tree growth variability during the current growing season, but negative during the previous growth period. Growth variability in our northern study site was in agreement with other populations that represent almost the full range of P. tarapacana latitudinal distribution (~ 18ºS to 23ºS). Towards the south of the P. tarapacana TRW network there was a decrease in the strength of the agreement of growth variability with our site,with the exception of higher correlation with the two southeastern sites. Similarly, the TRW chronologies recorded higher sensitivity to ENSO influences in the north and southeastern locations, which are wetter, than the drier southwestern sites . These patterns hold for the entire period, as well as for periods of high and low ENSO activity. Overall, P. tarapacana tree growth at the north of its distribution is mostly influenced by prior year moisture availability and current year temperature that are linked to large-scale climate patterns such as the SASM and ENSO, respectively.     

中国西北干旱区降水时空分布特征

利用中国西北干旱区122个气象站点1961—2011年月降水量资料,运用线性趋势、Mann-Kendall非参数趋势和突变检验法、Morlet小波分析等方法研究了西北干旱区降水量空间分布及多时间尺度下的变化规律和趋势。结果表明:近50年来西北干旱区降水量呈增加趋势,95.9%的站点有增湿特征,全区增湿趋势为9.31mm/10a(P0.01),但增湿幅度存在区域差异性,其中祁连山亚区(38.67mm/10a)增湿最明显;从季节来看,冬季增湿具有全区普遍性,但夏季增湿的区域差异性特征明显。全区及各亚区降水量在20世纪80年代至90年代初有明显的突变特征,除内蒙西部亚区外均通过了0.01的显著性水平检验,降水量序列存在4、8、12a和22a振荡周期,其中22a尺度振荡周期最强,其次是12a尺度。全区32%的年份降水量属正常范围,偏干年份为24%,异常偏干年份为12%,异常偏湿和偏湿年份均为16%。20世纪70年代之前降水量略低于标准降水均值,80年代开始有区域性增湿趋势,90年代之后全区增湿均较明显,正距平年数比例由70年代的10%上升至21世纪初的80%,西北干旱区整体处于相对湿润时段,且增湿趋势明显。     

Stream Restoration in the Pacific Northwest: Analysis of Interviews with Project Managers

Hundreds of millions of dollars per year are spent on river restoration in the Pacific Northwest (PNW), but little is known about the effectiveness of this effort. To help address this gap, we analyzed a database containing 23,000 projects at 35,000 locations in the region. We selected a subset of these projects for interviews using a survey instrument developed by a national team of scientists. In total, 47 project contacts in the PNW were interviewed to learn from the individuals directly involved in restoration. At least one‐third of the projects surveyed (34%) did not conduct sufficient monitoring to evaluate effectiveness. More than two‐thirds (70%) of all respondents reported their projects were successful, but 43% either have no success criteria or are unaware of any criteria for their project. Although almost two‐thirds (66%) of respondents anticipate a need for ongoing project maintenance, less than half (43%) have maintenance funds available. These findings suggest that establishing a connection between effectiveness monitoring and project implementation is not a usual component of project design. Consequently, we can only assess the benefits in a few isolated projects and cannot quantify the cumulative benefits of restoration on a larger scale. These findings highlight the need for (1) planning prior to implementation of restoration projects that accounts for monitoring design; (2) coordinated effectiveness monitoring to assess cumulative effects of restoration; and (3) management and maintenance of projects based on real measures of project performance.     

The Massaciuccoli Holocene pollen sequence and the vegetation history of the coastal plains by the Mar Ligure (Tuscany and Liguria,Italy)

A 90 m deep core from the Massaciuccoli lake basin (Tuscany, Italy) offers new material for improving the knowledge of the Holocene vegetation history in the coastal plains in Tuscany and Liguria bordering the Mar Ligure (Ligurian sea). In this paper, an assessment of the upper part of the core is presented. During the Holocene, the area was covered by woodlands whose composition changed in time. Numerous oscillations of the tree taxa were recorded which can probably be connected to sea level variations that had a strong influence on the depth of the water table. Human impact is evident particularly at ca. 4200–2500 b.p. when traces of opening of the woodland accompanied by noticeable pollen percentages of Vitis could suggest an early agricultural practice favouring this native plant. The new data have been integrated with previous palaeobotanical and archaeobotanical research. The occurrence of coastal wetlands has been shown. Throughout the Holocene, Mediterranean evergreen vegetation is generally poorly represented; it becomes widespread only in the late Holocene, suggesting that its establishment was probably favoured by the management practices in the coastal plains, particularly land reclamations, starting from the Roman period.     

Options for biodiversity conservation in managed forest landscapes of multiple ownerships in Oregon and Washington,USA

We examine existing and developing approaches to balance biodiversity conservation and timber production with the changing conservation roles of federal and nonfederal forest land ownerships in the US Pacific Northwest. At landscape scales, implementation of the reserve-matrix approach of the federal Northwest Forest Plan in 1994 was followed by proposals of alternative designs to better integrate disturbance regimes or to conserve biodiversity in landscapes of predominantly young forests through active management without reserves. At stand scales, landowners can improve habitat heterogeneity through a host of conventional and alternative silvicultural techniques. There are no state rules that explicitly require biodiversity conservation on nonfederal lands in the region. However, state forest practices rules require retention of structural legacies to enhance habitat complexity and establishment of riparian management areas to conserve aquatic ecosystems. Habitat Conservation Plans (HCPs) under the US Endangered Species Act provide regulatory incentives for nonfederal landowners to protect threatened and endangered species. A state-wide programmatic HCP has recently emerged as a multi-species conservation approach on nonfederal lands. Among voluntary incentives, the Forest Stewardship Council certification comprehensively addresses fundamental elements of biodiversity conservation; however, its tough conservation requirements may limit its coverage to relatively small land areas. Future changes in landscape management strategies on federal lands may occur without coordination with nonfederal landowners because of the differences in regulatory and voluntary incentives between ownerships. This raises concerns when potentially reduced protections on federal lands are proposed, and the capacity of the remaining landscape to compensate has been degraded.     

Trends in marine biological invasions at local and regional scales: the Northeast Pacific Ocean as a model system

Introduced species are an increasing agent of global change. Biogeographic comparisons of introduced biotas at regional and global scales can clarify trends in source regions, invasion pathways, sink regions, and survey effort. We identify the Northeast Pacific Ocean (NEP; northern California to British Columbia) as a model system for analyzing patterns of marine invasion success in cool temperate waters. We review literature and field surveys, documenting 123 introduced invertebrate, algal, fish, and vascular plant species in the NEP. Major invasion pathways were shipping (hull fouling, solid and water ballast; 1500s-present) and shellfish (particularly oysters) and finfish imports (commonest from the 1870s to mid-1900s). The cumulative number of successful invasions over time increased at linear, quadratic, and exponential rates for different taxa, pathways, and regions within the NEP. Regional analysis of four major NEP estuaries showed that Puget Sound and the contiguous Straits had the most introduced species, followed by Humboldt Bay, Coos Bay and Willapa Bay. Data on cumulative shipping volumes predicted smaller-scale, but not larger-scale spatial patterns in the number of shipping-mediated invasions. We identify the major challenges in scaling up from regional to global invasion analysis in cool temperate regions. Retrospective analyses for distinct biogeographic regions such as the NEP provide insight into vector dynamics and regional invasibility, and are a necessary foundation for monitoring and managing global change caused by biotic invasions.     

A signal for independent coastal and continental histories among North American wolves

Relatively little genetic variation has been uncovered in surveys across North American wolf populations. Pacific Northwest coastal wolves, in particular, have never been analysed. With an emphasis on coastal Alaska wolf populations, variation at 11 microsatellite loci was assessed. Coastal wolf populations were distinctive from continental wolves and high levels of diversity were found within this isolated and relatively small geographical region. Significant genetic structure within southeast Alaska relative to other populations in the Pacific Northwest, and lack of significant correlation between genetic and geographical distances suggest that differentiation of southeast Alaska wolves may be caused by barriers to gene flow, rather than isolation by distance. Morphological research also suggests that coastal wolves differ from continental populations. A series of studies of other mammals in the region also has uncovered distinctive evolutionary histories and high levels of endemism along the Pacific coast. Divergence of these coastal wolves is consistent with the unique phylogeographical history of the biota of this region and re-emphasizes the need for continued exploration of this biota to lay a framework for thoughtful management of southeast Alaska.     

湘西北蜡梅群落特征的初步研究

从５个样地９００ｍ２的调查资料对湘西北蜡梅群落进行了初步分析,结果表明：（１）群落种类组成丰富,共有维管束植物８０科,１３０属,１６６种。地理成分复杂,温带成分略占优势并表现出由热带向温带渐次过渡的性质;（２）外貌特殊,主要由革质、单叶和中型叶为主的落叶高位芽植物所决定,季相交替明显并与其他植被显著不同;（３）群落结构可分为林木层、小灌木层、草本层和地被层,其中林木层还可分为３个亚层,各层均以蜡梅占优势。林木结构分析表明,该群落具有一定的稳定性,属于亚热带区域的一类次生的暖性落叶阔叶灌丛,建议加强保护与开发利用的研究。     

Les ongulés en périgord et Nord-Ouest du Quercydurant le würm III. Chronoclimatologie,paléobiogéographie,palethnologie

The studies of Ungulate associations present in Würm III deposits of Southwest France lead to state biological paleoenvironments and paleoclimates more precisely. The second climatic phasis brought to light by H. Laville in Perigord seems cold and dry and the third one (Arcy) would be the most temperate and humid phasis during the Würm III period. Two posterior climatic ameliorations (fifth phasis = «Kesselt and seventh phasis = Tursac) are separated by a colder period. From the eighth phasis, a climatic threshold is crossed; paleontological as well as geological and palynological studies show the establishment of global cold conditions which would continue after Würm III–IV «interstadial (Laugerie). This one looks like a minor humid oscillation.Although data come from geographically close sites, clear differences appear between contemporary faunal associations. In Perigord, Ungulate associations strongly vary during the first seven phasis whereas in Northwest Quercy, in Auniac plain, Reindeer dominates all along this period.Lastly, comparisons between the results of paleontological,geological and palynological studies enable us to approach the question of the game choice made by prehistoric men. The perigordian men who inhabit La Ferrassie rockshelter during the sixth climatic phasis preferentially hunt Reddeer. They deliberately give up hunting other Ungulates yet well represented in contemporary levels of not distant sites.     

Social Identity and Culture Change on the Southern Northwest Coast

Driven by the participation of Native American people in the contemporary political, cultural, and academic landscape of North America, public and academic discussions have considered the nature of contemporary American Indian identity and the persistence, survival, and (to some) reinvention of Native American cultures and traditions. I use a case study—the historical anthropology of the Native American people of the Oregon coast—to examine the persistence of many American Indian people through the colonial period and the subsequent revitalization of "traditional" cultural practices. Drawing on archaeological data, ethnohistorical accounts, and oral traditions, I offer a reading of how, set against and through an ancestral landscape, traditional social identities and relationships of gender and authority were constructed and contested. I then consider how American Indian people negotiated the new sets of social relationships dictated by the dominant society.