Response of bird assemblages to windstorm and salvage logging — Insights from analyses of functional guild and indicator species

Natural disturbances, such as fire, windstorms and insect outbreaks, are important drivers of biodiversity in forest ecosystems, but at the same time cause large economic losses. Among the natural disturbances in Europe, windstorms cause the highest economic loss. After such storms, damaged forest stands are commonly salvage logged to restore economic value. However, such interventions could affect species assemblages of various taxonomic groups, including breeding birds. Despite these potential effects, investigations of the impacts of post-storm logging are largely lacking. We thus investigated assemblages of breeding birds in 21 logged and 21 unlogged windstorm-disturbed forest plots and 18 undisturbed, control forest plots using fixed-radius point-stop counts three, five and seven years after a windstorm within the Bavarian Forest National Park as part of the European Long-Term Ecosystem Research Network. We recorded 2100 bird individuals of 55 bird species. Bird assemblages were predominantly altered by the consequences of the windstorm and affected only to a minor degree by subsequent logging of storm-felled trees. Nevertheless, bird species richness was significantly reduced by post-storm logging within the first season. In general, the windstorm led to a shift in bird assemblage composition from typical forest species towards open- and shrub-land species. Assemblages of logged and unlogged disturbed plots consisted mainly of long-distance migrants and ground-foraging bird species, whereas assemblages of undisturbed control plots consisted of resident species that forage within vegetation. Both unlogged and logged storm-felled coniferous forest stands were inhabited by endangered or declining bird species, such as Water Pipit (Anthus spinoletta) on logged plots and Eurasian Redstart (Phoenicurus phoenicurus) on unlogged plots. Indicator species analyses suggested that species of unlogged storm disturbed plots depended on storm-created legacies, such as pits and snags, for foraging and nesting. Hence, we recommend reducing post-storm logging of these legacies to support species restricted to unlogged disturbed forest. To increase the diversity of breeding birds on the landscape scale, diverse logged and unlogged post-disturbance stands should be provided, which could be gained by a partial benign neglect strategy of storm disturbed forest stands.     

Diversity Patterns of Bornean Butterfly Assemblages

Borneo contains a diverse rainforest butterfly community, but its forests are under threat from logging and ENSO- (El Niño Southern Oscillation) induced fires. Contrasts in butterfly assemblage structure were examined in nine 450 ha landscapes in logged forest, primary unburned continuous and isolated forest, and forest affected by surface fires during the 1997/98 ENSO event. Temporally the effect of the 1997/98 ENSO event was followed in a single burned landscape from 1997 to 2004. In total, 517 species were present in 190 sampling sites. There was a five-fold difference in species richness among landscapes, with highest richness in continuous landscapes and lowest richness in burned landscapes. Richness was also higher in logged forest than proximate unlogged forest. Temporally, species richness dropped dramatically from 1997 to 1998, but afterwards increased remaining, however, substantially lower than pre-ENSO (1997) sampling. Sites in burned landscapes were distinct from other sites in terms of vegetation structure with the slash-and-burn area the most dissimilar to other landscapes. There was much less structure among unburned landscapes. The pattern of butterfly community composition was similar to that of vegetation structure with the community from the slash-and-burn area the most distinct. However, there was much less overlap among sites from different landscapes. Temporally, 1998 possessed the most distinct assemblage when compared to assemblages from other years. The community composition was, however, slowly returning to a pre-disturbance composition. Variance in community composition explained by environmental and spatial factors differed substantially among landscapes. The spatial fraction was the only explanatory component in recently burned landscapes and a proximate small unburned isolate, but explained no variation in logged landscapes. The environmental fraction explained substantial amounts of variation in logged landscapes and the slash-and-burn area. When all landscapes were pooled high proportions of variation in butterfly community composition were explained by both geographic distance between sites and environmental variables. In contrast when only unburned landscapes were considered, most variation was explained by the geographic distance among them. Despite differences among landscapes there was a general pattern of relatively sharp decline in similarity at short distances that levels out over greater distances, a result that agrees with previous studies on other tropical species assemblages.     

Nocturnal primates of kibale forest: Effects of selective logging on prosimian densities

To evaluate the potential impact of logging on nocturnal primates, densities ofGalago demidovii, G. inustus, andPerodictus potto were determined in two areas of the Kibale Forest Reserve, Uganda. One of these areas had been logged at a moderate level in the late 1960's, while the second area was relatively undisturbed. The density of the nocturnal primates was lower in the logged area than in the neighboring unlogged area. For the most frequently sighted nocturnal primate,G. demidovii, sightings were spatially clustered both within a year and between years, suggesting that clumped resources and/or social factors were influencing space use.     

Slow understory redevelopment after clearcutting in high mountain forests

Besides natural tree regeneration itself, the development of the forest understory community is highly indicative of the ecological recovery of forest stands post-harvesting, and therefore of the sustainability of forest management. High mountain forests might show particularly slow recovery of the understory plant community because of harsh environmental conditions. We compared understory community richness and composition among three age classes of forest stands in the subalpine Engelmann Spruce–Subalpine Fir zone in the interior of British Columbia, Canada. Species composition was found to differ significantly between mature stands (>110 years old and never harvested) and both recent clearcuts (5–8 years old) and the oldest clearcuts present in the study area (second growth: 24–28 years old). A non-metric multidimensional scaling (NMDS) ordination revealed no unidirectional return of species composition in harvested stands towards that of mature forest; indeed, plots in recent clearcuts and second growth stands were similar to one another and clearly separated from the mature stands. Indicator Species Analysis revealed that moss species were particularly indicative of mature forest, with four moss species being common in mature stands but absent from both younger stages. Compared to what has been reported for lower elevation coniferous forests, e.g. in the U.S. Pacific Northwest, redevelopment of the understory appears to be slow after harvesting in these high elevation mountain forests. Rotation intervals that consider the natural temporal pattern of species turnover and the occurrence interval of major natural disturbances (here: fire) should provide effective approaches to sustainable forest management of these forests.     

Effects on vegetation composition of a modified forest harvesting and propagation method compared with clear‐cutting,scarification and planting

Question: How does the vegetation of boreal forests respond to harvesting and scarification? Location: 650 m a.s.l., central Sweden (61°38’ N). Methods: The response of boreal forest vegetation to cutting and scarification was studied in a field trial, which consisted of three treatments plus conventional harvesting as a control in a complete block design with four replicates. The cutting was done 14 years prior to vegetation inventory and scarification and planting were conducted the first or second years after cutting. Results: The species most abundant at higher cutting intensities were crustose lichens, Cladonia spp., Cladina arbuscula, Polytrichum spp. and pioneer mosses, the grass Deschampsia flexuosa, and the tree Betula pubescens, A few species had substantially lower abundance in treatments with higher cutting intensity, notably Hylocomium splendens and Vaccinium myrtillus. Scarification had a strong effect that was different from the one created by cutting. In scarification treatments, Polytrichum spp. were the only species with high abundance; most species had low abundance, i.e. Barbilophozia lycopodioides, Vaccinium vitis‐idaea, Pleurozium schreberi, Carex globularis, Empetrum nigrum, Cladina arbuscula, Sphagnum spp. Conclusions: Our results elaborate on the details of the well‐known effect of cutting on ground‐layer flora, and also give support for the profound and long‐lasting effect that soil scarification has on forest vegetation.     

Quantifying successional changes in response to forest disturbances

Question: Can dissimilarity measures of individual plots be used to forecast the driving factors among various anthropogenic disturbances influencing understorey successional changes? Location: Yambulla State Forest, south‐eastern Australia (37°14'S, 149°38'E). Methods: Assessments of understorey vegetation communities were taken prior to anthropogenic disturbances and at three subsequent time periods representing a period of 15 years post‐disturbance. Dissimilarities were calculated from the original assessment and modelled in a Bayesian framework to examine the influence of logging, number of prescribed burns and time. Results: All sites underwent significant changes over time independently of the imposed management regimes. Logging resulted in an immediate change in vegetation assemblage which decreased in the subsequent assessments. The number of prescribed fires brought greater change in the shrub vegetation assemblages, but less change in the ground species vegetation assemblages. Conclusions: The anthropogenic disturbances did have some role in the changes of vegetation assemblages but these were minimal. The ongoing changes appear to be a natural response to the last wildfire, which passed through the study area in 1973 (13 years prior to the study). Forest management practices should consider the influence of wildfire succession when planning for the conservation of biodiversity.     

emperature and oil,and has a stable dis

ld,so we present the well logging series and gas drilling technique suited to Daqing area.Some proper logging evaluation approaches are used such as GR spectrometry log,CN log,induction log and NMR log,etc.well logging;technology;gas drilling;foam drilling;casing drilling;Daqing oilfield0测井技术Well Logging Technology20-22 104P631.8B019;B021;A011;A012;C;21;D3;A;B;B019_21;A011_D3;A012_C;B021_21;赵平;16-18 100高孔密复合射孔技术研究周志华;谭忠健;刘富奎;西安通源石油科技股份有限公司,中海石油(中国)有限公司天津分公司勘探部,中海石油(中国)有限公司天津分公司勘探部 陕西西安710065,天津300452,天津300452复合射孔;;高孔密;;p-t过程测试;;现场应用提出了一种新型装药结构并实现在高孔密条件下的复合射孔,所开发的产品进行了地面混凝土靶测试、地面动态压力-时间(p-t)过程测试和现场应用试验。试验结果表明,高孔密复合射孔器能够将高孔密的多孔道、多相位的射孔特点与高能气体压裂造缝机理有机地结合,形成了孔缝结合的深穿透、高孔密和多相位的沟通通道,有效地改善了近井带的渗流能力,实现了油井的高产和稳产。现场应用效果良好。On High Foramen Density Technology for the Fracture Perfo     

Postfire forest management and Mediterranean birds: the importance of the logging remnants

Fire is a crucial element needed to understand the biodiversity patterns of forest landscapes in most Mediterranean countries. However, little is known about the quantitative responses of bird communities to postfire forest management in this region, in which the logging of burnt trees is a common practice. Several studies have already described the negative effects of felling burnt trees on birds but none has focussed on the remaining wood remnants. We investigated this question in a large burnt area located in north-east Iberian Peninsula. The amount of logging remnants left on the ground had positive linear and negative quadratic relationships with the indices of bird abundance and bird richness. The results obtained at a species level were similar, since 36% of the most abundant species revealed the same type of relations with logging remnants, whereas none showed an opposite pattern. Thus, birds in general seem to be positively influenced by the amount of wood remnants left on the ground to a certain point, from which the relation reverses. The results of this study indicate that a moderate amount of wood remnants left on the ground may be positive for the overall bird community. We suggest that management plays a role in the recovery of the bird community after fire and, therefore, biodiversity criteria should be incorporated in the guidelines driving postfire actions.     

Forest fragmentation, synergisms and the impoverishment of neotropical forests

It is well documented that the negative effects of habitat fragmentation are strong enough to promote local as well as regional extinction of canopy and emergent trees in neotropical forests. However, forest fragmentation does not occur alone, but is always associated with other human-induced threats to trees, such as logging, forest burning and hunting of key vertebrate seed dispersers within forest remnants. This association occurs because forest resources are, at least during a certain period, the main income source for local human populations. It is now possible to establish how these threats act in concert causing tree species impoverishment. Based on a predictive model, it is predicted that the most fragmented forest regions have lost or will lose an important part of their tree diversity. New integrated research must urgently test this prediction and investigate how human activities might be regulated in both old and new tropical forest frontiers to avoid species loss. If we fail to do this we will miss the opportunity of proposing sound and efficient guidelines to rescue neotropical forests from species impoverishment.