What factors influence the diversity of saproxylic beetles? A multiscaled study from a spruce forest in southern Norway

The diversity in different groups of obligate saproxylic beetles was related to ecological variables at three levels of spatial scale in mature spruce-dominated forest. The variables were connected to: (i) decaying wood, (ii) wood-inhabiting fungi, (iii) the level of disturbance, (iv) landscape ecology, and (v) vegetational structure. Several strong relationships were found at medium (1 km²) and large scales (4 km²), while only weak relationships were found at a small scale (0.16 ha; 1 ha=10⁴ m²). This may be explained by the local variations in habitat parameters and the high mobilities of many beetle species. Factors connected to decaying wood and wood-inhabiting fungi were clearly the most important factors at all scale levels. In particular, the variables diversity of dead tree parts, number of dead trees of large diameter and number of polypore fungi species increased the species richness of many groups and increased the abundance of many species. Eight species were absent below a certain density of decaying wood per 1 or 4 km². Former extensive cutting was a negative factor at large scale, probably because of decreasing recolonization with increasing distance to the source habitats. Thinning reduced the diversity of species associated with birch. The development of guidelines favouring the diversity of saproxylic beetles are discussed below.     

Analysis of forestry impacts and biodiversity in two Pyrenean forests through a comparison of moth communities （Lepidoptera, Heterocera）

We have compared the biodiversity variations in moth communities between unmanaged forests and commercial forests in a mountainous environment （Pyrenees France）. The aim was to evaluate the impact of forestry activities on moth diversity. The data collected from the insects were analysed with a Bayesian specific similarity index （noted SSP index） and by statistical biodiversity indexes comparison. It was seen that diversity and richness were decreased in the plantation compared to the unmanaged forest. Interestingly, the composition of the communities of moths was shown to be not only related to the presence/absence of host plants, but also to be in relation with changes in the differences in forest architecture （i.e. the relative coverage by the different vegetation levels）. However, the moth community in the commercial forest still has a high capacity to converge with the moth community present in more natural forests. We report here a list of 177 species of moths, providing information on the distribution of some uncommon species, poorly studied as yet in the Pyrenees.     

Is there more insect folivory in warmer temperate climates? A latitudinal comparison of insect folivory in eastern North America

1.  It is generally believed that warmer climate forests suffer more herbivory, as a proportion of leaf area, than cooler climate forests. However, standardized studies using the same methodology have rarely been performed.
2.  We carried out a study on scattered forest-edge populations of four widespread tree species ( Quercus alba , Acer rubrum , Fagus grandifolia and Liquidambar styraciflua ) spanning 17° of latitude in North America.
3.  We sampled early summer sun leaves (12 weeks after bud break) at each latitude in 2 years. Total insect folivory damage was estimated from the percentage area damaged in fresh leaves on forest edges, using a scanner-linked software.
4.  The percentage area damage per leaf of all four species in both years shows a significant latitudinal trend, with less damage in lower latitude areas of eastern North America. This is contrary to what would generally be expected according to current ecological thinking. Among the four studied species, only A. rubrum showed a significant difference between the 2 years.
5.   Synthesis . The observation of an inverse latitudinal trend may have wider implications for the study of community functioning, suggesting that strength of 'biotic' interaction between plants and herbivores might actually be no less important, or in fact more important, in cool temperate climates compared with warm temperate climates.     

Does timing of boron application affect needle and bud structure in Scots pine and Norway spruce seedlings?

Loss of apical dominance is a well-known boron (B) deficiency symptom in trees. Recent field studies indicate that B deficiency may cause irreversible damage in emerging leader buds leading to bushy growth, and changes in developing needles in mature Norway spruce trees. We experimentally studied if timing of B application affects needles and buds of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings with low initial B levels. The treatments were: no B (B0); B supply from the beginning of the simulated summer (B1); starting soon after bud burst (B2) and starting at the occurrence of first needle primordia in new spruce buds (B3). At the end of the experiment, B concentration in B1 was 23 mg kg⁻¹ (pine) or 17 mg kg⁻¹ (spruce) and lower in the later applications. In B0 it was at deficiency limit. In B0, B2 and B3, there were fewer sclerenchyma cells, and cavities occurred in vascular cylinders in pine needles, and in spruce buds there were more tanniferous cells in the primordial shoots compared to B1. Furthermore, in all but B1 there was cell collapse in the bud apex of some spruce seedlings. The experimentally induced changes were the same as earlier reported in B deficient conifers in the field, and indicate, similarly as in the field that adequate B is necessary throughout the growing season for healthy growth, particularly for spruce. The differences between spruce and pines are due, at least partly, to the differences in time frame of needle development and in the differences in development of conducting tissues in the buds.     

Wildlife farming: an alternative to unsustainable hunting and deforestation in Neotropical forests?

Wild animals have been a source of food and income through subsistence hunting by forest-dwelling people in Neotropical countries in spite of the fact that hunting appears to be unsustainable as it leads to the depletion of wild fauna. Laws in Brazil and other Latin American countries forbid hunting but allow the commercial use of captive-bred animals. Notwithstanding the fact that this is a controversial topic among conservationists, in this paper we propose that wildlife farming in the Neotropics can be an alternative to the over-hunting and deforestation that are carried out for the production of traditional food and pastures for livestock. This review sets out this proposal, and discusses the implications for tropical forest integrity and rural population dependency on forest resources. We discuss the ecological and economical advantages of wildlife farming and its constraints as a conservation tool, using collared peccary (Pecari tajacu) farming in the Amazon region as a model. Productivity levels may reach 19,000 times higher than those obtained from the management of peccaries from forests in the Amazon region. This can be achieved with an easily obtainable diet composed of forest fruits and locally available agricultural by-products. Therefore, establishing captive management programs for peccaries is an effective way of avoiding wild stock depletion, deforestation, and guaranteeing the livelihood of forest dwellers in the Neotropics. However, it is essential that governmental and/or non-governmental agencies be involved in providing subsides to establish peccary farms, provide technical assistance, and introducing peccary captive breeding centers to supply founder stock.     

Is phospholipase D really an enzyme? A comparison of in situ and in vitro activities.

Leaf phospholipase D activity was compared in vitro and in situ. In the in situ reaction stimulated by methanol only phosphatidylcholine and phosphatidylethanolamine were degraded until approx. 80% of these endogenous substrates had been consumed. Only then was a limited amount (approx. 20%) of endogenous phosphatidylglycerol degraded. Endogenous phosphatidylinositol was apparently not susceptible to phospholipase D in situ. In the vitro reaction the relative susceptibilities to degradation of added phospholipid substrates were (a) in the absence of "activators" phosphatidylethanolamine greater than phosphatidylglycerol greater than phosphatidylcholine, (b) in the presence of diethyl ether phosphatidylcholine greater than phosphatidylethanolamine greater than phosphatidylglycerol and (c) in the presence of sodium dodecyl sulphate phosphatidylcholine greater than phosphatidylethanolamine = phosphatidylglycerol. Minimum rates calculated for the in situ reaction in cauliflower leaf were 5-fold higher than maximum in vitro rates reported for the same material. Phospholipase D activity has been demonstrated by the in situ reaction in all leaf tissue so far examined. From these data we conclude that phospholipase D may be an integral part of membranes containing phosphatidylcholine and phosphatidylethanolamine, but not of membranes containing phosphatidylglycerol. We also suggest that phospholipase D may not be a physiological enzyme, but rather a structural protein of phosphatidylcholine- and phosphatidylethanolamine-containing membranes and which, under certain non-physiological conditions, possess enzymic properties.     

The extent and meaning of hybridization and introgression between Siberian spruce (Picea obovata) and Norway spruce (Picea abies): cryptic refugia as stepping stones to the west?

Boreal species were repeatedly exposed to ice ages and went through cycles of contraction and expansion while sister species alternated periods of contact and isolation. The resulting genetic structure is consequently complex, and demographic inferences are intrinsically challenging. The range of Norway spruce (Picea abies) and Siberian spruce (Picea obovata) covers most of northern Eurasia; yet their geographical limits and histories remain poorly understood. To delineate the hybrid zone between the two species and reconstruct their joint demographic history, we analysed variation at nuclear SSR and mitochondrial DNA in 102 and 88 populations, respectively. The dynamics of the hybrid zone was analysed with approximate Bayesian computation (ABC) followed by posterior predictive structure plot reconstruction and the presence of barriers across the range tested with estimated effective migration surfaces. To estimate the divergence time between the two species, nuclear sequences from two well‐separated populations of each species were analysed with ABC. Two main barriers divide the range of the two species: one corresponds to the hybrid zone between them, and the other separates the southern and northern domains of Norway spruce. The hybrid zone is centred on the Urals, but the genetic impact of Siberian spruce extends further west. The joint distribution of mitochondrial and nuclear variation indicates an introgression of mitochondrial DNA from Norway spruce into Siberian spruce. Overall, our data reveal a demographic history where the two species interacted frequently and where migrants originating from the Urals and the West Siberian Plain recolonized northern Russia and Scandinavia using scattered refugial populations of Norway spruce as stepping stones towards the west.     

Gap size and succession in cutover southern Appalachian forests: an 18 year study of vegetation dynamics

We used clearcut logging in establishing four replicated sizes of canopy openings (0.016, 0.08, 0.4, and 2.0 ha) in a southern Appalachian hardwood forest in 1981 to examine the long-term effects of disturbance size on plant community structure, biomass accumulation, aboveground net primary productivity (NPP), and mode of recovery. The reestablishment of NPP and biomass following logging was 6–7-fold greater in large than small openings by 17 years. Total biomass in the 2.0 ha openings (127.3 Mg ha⁻¹) recovered 59.5% as NPP (19.7 Mg ha⁻¹ yr⁻¹) reached 225% of precut forest levels. Biomass accumulation was 2.6–3.6-fold greater in interior than edge locations of all but the 0.016 ha gaps. The absence of significant patch size or edge vs. interior differences in tree densities suggests that growth rates of individual trees were enhanced in more insolated microenvironments. Sprouting (86–95% of tree NPP) was much more important than advance regeneration (4–10%) or seedling germination (<2%) during early recovery in all opening sizes. Canopy dominant Quercus and Carya trees exhibited limited sprouting following disturbance. Instead, shade-intolerant Robinia pseudoacacia and Liriodendron tulipifera were major sprouters that used N-fixation (Robinia) and rapid growth (Liriodendron) in attaining 7.4 and 5.9 fold greater biomass accumulation, respectively in 2.0 ha than 0.016 ha opening sizes. Seedling germination and understory production were extensive in all openings following logging, but declined rapidly as the young tree canopy began closing by 4–6 years. The relative importance of shade-intolerant tree biomass approximately doubled over 17 years as shade-tolerant tree seedlings, herbs, and shrubs gradually regained importance under the emerging canopy. Sprouting caused the persistence of a tree species composition in all openings that remained relatively similar to the precut forest. Large disturbances on mountain slopes of the southern Appalachians generally promote sprouting and rapid recovery, whereas small disturbances in low-elevation cove forests lead to a gradual recovery through seedling germination and/or advance regeneration. Continued logging in the southern Appalachians will increase the relative size and frequency of large disturbances, further the importance of sprouting of shade-intolerant species, and lead to more even-aged forest stands throughout the region.     

Morphometric comparison of Simulium perflavum larvae (Diptera: Simuliidae) in relation to season and gender in Central Amazônia, Brazil

Number of larval instars, age structure and environmental effects on these parameters represent basic information in the study of insect population biology. When species have economic importance, this information is essential in order to choose the best period to apply different control methods and to determine the stages of the life cycle of the insect that are most susceptible to each treatment. The family Simuliidae has many species of medical/veterinary importance in the world, and some studies in the temperate region have suggested that the number of larval instars and the larval size can vary according to the season, gender and some environmental factors, such as temperature and diet. This study, with the zoophilic species Simulium perflavum Roubaud, is the first in the Neotropics observing some of these factors and will serve as a template for other species of medical importance in the region. S. perflavum larvae were collected in five streams in Central Amaz?nia (Manaus and Presidente Figueiredo counties, State of Amazonas), in Sept./Oct. 1996 (dry season) and Feb./Mar. 1997 (rainy season). These larvae were measured (lateral length of head capsule and width of cephalic apodema) to determine the number of larval instars (n=3985), to compare the larval size between seasons and genders (last and penultimate larval instars, n=200). Seven larval instars were determined for this species using frequency distributions, t-tests and Crosbys growth rule. Significant differences were not detected (t-test, p>0.05) in larval size between seasons and genders. Our results differ from some found in temperate regions suggesting that in the Neotropical region the larval size in different seasons and different genders remains constant, although some environmental parameters, such as diet, change depending on the season.     

Triggering and predisposing factors in the “Red” decline syndrome of Norway spruce (Picea abies)

Summary Analysis of 62 mature Norway spruce (Picea abies provenance Viborg) trees growing in a Danish plantation was undertaken along with analysis of their nutrient contents (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, B and Na), in each of the three youngest needle age classes, from branches of four exposure directions near the tree top. The aim was to investigate if one among the studied possible predisposing factors was also a triggering factor in the 1989 outbreak of the Red Norway spruce decline in Denmark. Neither nutrient imbalance or deficiency, nor excessive N-deposition or salt-stress were indicated as triggering factors in 1989. The Red syndrome, noticeable for the bright red colour of the current-year needles, was found to be an extension of the European type Novel Decline. Red syndrome is similar to previously reported phenomena of top-dying and sub top-dying, in that it had fewer needle age classes and significantly higher contents of mobile cations (and Ca) in the younger needle classes. Tree ring analysis suggested that the Red syndrome was initiated in the early 1980s, when the trees experienced adverse climatic conditions. Because of this long-term development of the Red Norway spruce decline syndrome, it is concluded that a triggering factor is of minor importance relative to the multitude of predisposing factors.     

Workers, sexuals, or both? Optimal allocation of resources to reproduction and growth in annual insect colonies

Understanding decisions about the allocation of resources into colony growth and reproduction in social insects is one of the challenging issues in sociobiology. In their seminal paper, Macevicz and Oster predicted that, for most annual insect colonies, a bang–bang strategy should be favoured by selection, i.e. a strategy characterised by an “ergonomic phase” with exponential colony growth followed by a “reproductive phase” with all resources invested into the production of sexuals. Yet, there is empirical evidence for the simultaneous investment into the production of workers and sexuals in annual colonies (graded control). We, therefore, re-analyse and extend the original model of Macevicz and Oster. Using basic calculus, we can show that sufficiently strong negative correlation between colony size and worker efficiency or increasing mortality of workers with increasing colony size will favour the evolution of graded allocation strategies. By similar reasoning, graded control is predicted for other factors limiting colony productivity (for example, if queens’ egg laying capacity is limited).     

Impact of atmospheric nitrogen deposition on soil properties and herb-layer diversity in remnant forests along an urban–rural gradient in Guangzhou, southern China

Atmospheric nitrogen (N) deposition in subtropical metropolitan regions has increased greatly because of rapid urbanization, and such increase could lead to N-related changes in soil properties and plant diversity in remnant forests of urban ecosystems. To investigate the pattern of atmospheric N deposition along an urban?Crural gradient in metropolitan Guangzhou, southern China, and to assess the potential influence of N deposition on soil properties and understory plant diversity in remnant forests, precipitation, and soil samples were collected and vegetation was surveyed from four forest sites between March 2010 and March 2011. The atmospheric inorganic nitrogen deposition (DIN) decreased with increasing distance from the urban center: DIN inputs were 43.3, 41.2, 35.2, and 30.1?kg?N?ha^?1?year^?1 in two urban sites, a suburban site and a rural site, respectively. However, forest soil N status (NH₄ ⁺-N, NO₃ ^?-N, and total nitrogen) showed the opposite pattern. Understory herb-layer diversity was negatively correlated to DIN input and positively correlated to soil calcium (Ca) and potassium (K) concentrations and pH; with highest herb-layer diversity found in the rural site receiving the lowest amount of DIN input. These results indicated that higher DIN along with soil acidification and leaching of base cations (Ca and K) might change the current N status and increase nutrients leaching and thereby cause reductions in understory plant diversity. A regional policy linking atmospheric pollution and land protection is needed to protect the most N-sensitive herb species (e.g., forbs and ferns) in these remnant forests.     

Same Sámi? A comparison of self-reported Sámi ethnicity measures in 1970 and 2003 in selected rural areas in northern Norway

In post-war Norway, only the 1970 national census has recorded ethnicity information about the indigenous Sámi, however restricted to those living in selected areas in the north. In this study, we combine replies about Sámi ethnicity given by the same individuals in Norway’s 1970 census and in the population-based SAMINOR study in 2003–04, to compare self-reported Sámi ethnicity at two points in time that encompass a period when the effects of a long-standing assimilation policy gradually lost ground in favour of upcoming Sámi revitalization. We found self-reported Sámi ethnicity – measured as (1) Sámi as home language in each of three generations and (2) the respondent’s self-identification as Sámi – to have remained generally stable, but some changes were observed. We argue that the results reflect interplays between societal and individual factors. We conclude that any statistical study involving an indigenous people, when clarifying the ethnicity measures, should also address the issue of ethnic mobility.     

A comparison of the in vitro binding of α-tocopherol to microsomes of lung,liver, heart and brain of the rat

The in vitro binding of α-tocopherol to microsomes of lung, liver, heart and brain of the rat was studied with the insoluble tocopherol ligand presented as a complex with bovine serum albumin. Under these conditions, all microsomes showed nonsaturable binding of α-tocopherol and the amount bound to microsomes was linearly proportional to the concentration of albumin-complexed tocopherol. Increasing the amount of α-tocopherol bound to microsomes in this manner reduced the extent of lipid peroxidation induced by added ferrous iron. The apparent affinities of the microsomes for α-tocopherol, as indicated by the amount bound at a given concentration of albumin-complexed tocopherol, decreased in the order brain > liver ≈ heart > lung. The differences in affinity did not correlate with total fatty acid content (r = − 0.39), total unsaturated fatty acid content (r = − 0.26), or with the content of fatty acids containing two or more double bonds (r = − 0.01). A high positive correlation was found with the content of fatty acids containing three or more double bonds (r = + 0.96). Since lung microsomes contain approx. 6-times the tocopherol levels of liver and brain and about twice that of heart microsomes, these results show that the in vivo levels of microsomal tocopherol do not reflect microsomal affinity for this biological antioxidant.     

Assemblage structure and altitudinal distribution of lady beetles (Coleoptera,Coccinellidae) in the mountain spruce forests of Pol’ana Mountains,the West Carpathians

In two successive years we recorded a total of 3,636 individuals and 17 species of adult lady beetles (Coleoptera, Coccinellidae) in the spruce forests of Pol’ana Mts (the West Carpathians) at altitudes ranging from 600 m to 1,300 m a.s.l. Four lady beetle species were documented as predominating (dominance of abundance > 5%) over the study period. They were the following: Aphidecta obliterata (1,828 individuals and 50.3%), Coccinella septempunctata (634 individuals and 17.4%), Adalia conglomerata (594 individuals and 16.3%) and Anatis ocellata (279 individuals and 7.7%). The assemblages of lady beetles differed among the areas and also between the years. The season revealed neglegible effect on distribution of lady beetles, whereas the effect of altitude was more pronounced. A. conglomerata preferred the areas at lower altitude (600–725 m) to those at middle (900–925 m) and/or upper altitude (1,250–1,300 m). In contrast, A. obliterata and C. septempuctata were most abundant in the area at middle altitude. The altitudinal location of area partly explained the variability in abundance of lady beetles. The first ordination axis constructed by means of correspondence analysis (CA) represented an altitudinal gradient and accounted for 19.4% of the total variance of the species data. The great proportion of lady beetle species not typically associated with spruce and/or other coniferous trees than spruce (70.6%, n = 17) may be explained by an ecotonal effect.     

Exposure of children to residential magnetic fields in Norway: Is proximity to power lines an adequate predictor of exposure?

The aim of this work was to study the exposure to magnetic fields of children living at different distances from a power line and to evaluate how well theoretical calculations compared with actual exposure. Personal exposure instruments were carried for 24 h by 65 schoolchildren living 28–325 m from a 300 kV transmission line; the current load was 200–700 A. About half of the children attended a school far from the power line, whereas the other half attended a school located about 25 m from the line. Exposure to magnetic fields was analyzed for three categories of location: at home, at school, and at all other places. Time spent in bed was analyzed separately. The results indicated that children who lived close to a power line had a higher magnetic field exposure than other children. The power line was the most important source of exposure when the magnetic field due to the line was greater than about 0.2 μT. Exposure at school influenced the 24 h time-weighted average results considerably in those cases where the distance between home and power line was very different from the distance between school and power line. The calculated magnetic field, based on line configuration, current load, and distance between home and power line, corresponded reasonably well with the measured field. However, the correlation depends on whether home only or 24 h exposure is used in the analysis and on which school the children attended. The calculated magnetic field seems to be a reasonably good predictor of actual exposure and could be used in epidemiological studies, at least in Norway, where the electrical system normally results in less ground current than in most other countries. Bioelectromagnetics 18:47–57, 1997. © 1997 Wiley-Liss, Inc.