Can 'continuity indicator species' predict species richness or red-listed species of saproxylic beetles?

This study investigates the relationship between the abundance of wood-rotting fungus suggested as 'continuity indicator species' and environmental variables for the assemblage of saproxylic (wood-living) beetles associated with Fomitopsis pinicola fruiting bodies in a mature spruce forest in southeastern Norway. The presence of species thought to indicate continuity in old growth is one of the criteria used when finding and delineating small protected areas ('woodland key habitats') in Scandinavian forestry. Although it is clear that remnants of old-growth forest are important for many taxa, documentation as to which entities or species the indicator species indeed indicate is scarce. If stands with a continuous and unbroken input of dead wood have a unique assemblage of wood-rotting fungi, it seems relevant to ask if these stands also have a unique assemblage of rare saproxylic beetles. I find that the indicator species exhibit no significant correlations with beetle species richness or with the presence of red-listed saproxylic beetles as a group. The different characteristics of dead wood conditions are the most important environmental variables that explain both the species richness and the presence of red-listed beetles. Single-species analyses reveal contrasting relationships. The red-listed beetle Atomaria alpina shows a significant and positive association to the abundance of indicator species. Contrary, a group of three red-listed species with similar ecology in the family Cisidae exhibits a significant and negative association to indicator species abundance. This indicates that important patterns are concealed when considering general measures such as overall presence of red-listed beetles. Single-species studies are necessary in order to correctly understand how rare beetles respond to forestry activities and to develop a policy that can secure their continuing existence in the boreal forest.     

Synergistic impacts of sediment contamination and dam presence on river functioning

1. Dam presence is commonly associated with strong accumulation of polluted sediments. In spite of this context of multiple stressors, physical effects are often solely considered in the ecological assessment of the dam impacts. 2. We studied four ‘reservoir/downstream reach’ systems differing in levels of sediment contamination in reservoirs. Using assemblages and biotrait (i.e. ecological or biological attribute) responses of macroinvertebrate communities and leaf litter breakdown, we examined the individual effects and potential interactions between sediment contamination and dam presence along the gradient of ecotoxic pressure. 3. Leaf breakdown rates ranged from 0.0044° per day in the most contaminated reservoir to 0.0120° per day in the reference reservoir. Comparisons of community trait profiles among reservoirs highlighted a gradient of trait responses to sediment contamination. 4. In the absence of toxic contamination, the dam‐induced modifications in biotraits of invertebrate assemblages were not related to a reduction of leaf litter breakdown. Conversely, contaminated sediment in reservoir induced strong functional disturbances (i.e. bioecological shifts and reduction of leaf litter breakdown) downstream of dams. 5. Key biotrait categories positively related to leaf litter breakdown rate have been identified. They corresponded mainly to shredders and/or small‐sized (<0.5 cm) insects, using aquatic (e.g. crawlers) or aerial (e.g. fliers) active dispersal strategies. In addition, trait categories positively correlated to contamination level have been considered as ‘response’ traits. They corresponded to large‐sized (>4 cm) species, having several generations per year (polyvoltin), using asexual reproduction and/or disseminating by drift (aquatic, passive). 6. In the current context of ecological continuity restoration, this study has identified the risks associated with the presence of historical contamination in the run‐of‐river reservoirs for downstream ecosystem health.     

Vegetation and landscape connectivity control wildfire intervals in unmanaged semi‐arid shrublands and woodlands in Australia

Aim The aim of this study was to determine how spatial variation in vegetation type and landscape connectivity influence fire intervals in a semi‐arid landscape with low relief and complex mosaics of woodland and shrubland vegetation. Location Our study focused on a 15,500‐km² area of relatively undisturbed and unmanaged land in south‐western Australia, referred to as the Lake Johnston region. Methods We modelled fire‐interval data from a 67‐year (1940–2006) digital fire history database using a two‐parameter Weibull function, and tested for the effects of vegetation type and landscape connectivity on estimates of the length of fire intervals (Weibull parameter b) and the dependence of fire intervals on fuel age (Weibull parameter c). Results Vegetation type and landscape connectivity significantly influenced fire interval probability distributions. Fire intervals in shrublands (dense low shrub assemblage) were typically shorter (b = 46 years) and more dependent on fuel age (c = 2.33) than most other vegetation types, while fire intervals in open eucalypt woodlands were much longer (b = 405 years) and were less dependent on fuel age (c = 1.36) than in shrub‐dominated vegetation types. Areas adjacent to or surrounded by salt lakes burnt less frequently (b = 319 years) and fire intervals were less dependent on fuel age (c = 1.48) compared with more exposed areas (e.g. b < 101 years, c > 1.68). Fire intervals in thickets (dense tall shrub assemblage) were longer (b = 101 years) than would be expected from fuel loads, most likely because they were protected from fire by surrounding fuel‐limited woodlands. Main conclusions Fire intervals in south‐western Australia are strongly influenced by spatial variation in vegetation (fuel structure) and landscape connectivity. The importance of fuel structure as a control of fire intervals in south‐western Australia contrasts with other landscapes, where topographical gradients or climatic influences may override the effects of underlying vegetation. We found that, regardless of low relief, topographical features such as large salt lake systems limited the connectivity and spread of fire among landscape units in an analogous manner to lakes or mountainous features elsewhere.     

Populations of Lobaria pulmonaria (L.) Hoffm. in the Cansiglio Regional Forest (Veneto,Pre-Alps,north-east Italy): Distribution,diversity and conservation issues

Abstract

The distribution of the epiphytic macrolichen Lobaria pulmonaria (L.) Hoffm. was surveyed in the Regional Forest of Cansiglio, extending over 3,500 ha in the eastern part of the Veneto Pre-Alps (north-east Italy). Data on the main characteristics of the forest sites and on Lobaria trees were collected with the aim to evaluate the main ecological factors, related to forest composition and management, affecting the distribution of Lobaria pulmonaria. Lichen diversity was surveyed on 15 randomly selected Lobaria trees. A good correlation between macrolichens and the total number of species was found. The largest Lobaria populations are concentred in the north-eastern part of the forest, where mixed and multi-plane silver fir – beech formations prevail, and selective cutting is carried out. Our data has enabled us to develop some criteria for the identification of priority conservation sites for Lobaria pulmonaria and lichen diversity in the study area, improving the focus on biodiversity in the management of the forest.     

Giving More to Humans than to Animals in Need? A Behavioral Measure of Animal–Human Continuity in Large-scale Surveys

Survey research on attitudes and behavior toward animals is affected by the hypothetical character of behavioral measurements and socially desirable responses. Drawing on previous research in the fields of environmental behavior and behavioral economics, we combined the advantages of incentivized behavioral experiments and large-scale surveys by asking 2,299 participants in “dictator games” to allocate 10 euros between a charity for poverty reduction and themselves, as well as between a charity for animal protection and themselves (presented in counterbalanced order, with 200 allocations paid to the charities and participants). On average, participants donated approximately 70% of the 10 euros to each charity but donated slightly more money (0.42 euros) for poverty reduction than animal protection. Interestingly, participants allocated the same amount of money to the first charity (whether for humans or animals), but their second allocation depended on the charity and indicated an anthropocentric bias (i.e., higher allocations to poverty reduction than animal protection). Women donated more for animal protection than men, and stronger pro-animal attitudes were associated with higher donations for animal protection. We also found a positive effect of a “social desirability” scale on incentivized donations. In sum, our study finds that participants gave more to humanitarian than animal charities. However, this difference is less than fifty cents and, consequently, minor in magnitude.     

Robustness of an S‐Estimator in the One‐Way Random Effects Model

An S‐estimator is defined for the one‐way random effects model, analogous to an S‐estimator in the model of i.i.d. random vectors. The estimator resembles the multivariate S‐estimator with respect to existence and weak continuity. The proof of existence of the estimator yields in addition an upper bound for the breakdown point of the S‐estimator of one of the variance components which is rather low. An improvement of the estimator is proposed which overcomes this deficiency. Nevertheless this estimator is an example that new problems of robustness arise in more structured models.     

The diversity and community dynamics of hazelwood lichens and bryophytes along a major gradient of human impact

Background: Oceanic hazelwoods in western Scotland are hypothesised to be unmanaged post-glacial relicts, representing an unusual type of old-growth forest habitat in Europe. They are characterised by an exceptionally high epiphytic diversity, including their status as ‘hotspots’ for indicators of woodland ecological continuity.

Aims: The aim of this study was to evaluate the effects of climate, pollution and management on the occurrence of epiphytic lichens and bryophytes on Corylus avellana.

Methods: Thirteen hazelwood study sites were systematically sampled along a climate, pollution and management gradient in Britain. Epiphyte composition and richness were examined in a strict hierarchical framework, and compared against site-, stool- and stem-scale environmental predictors.

Results: The study showed that along the gradient from ‘clean-air’ relict sites to ‘polluted’ coppiced sites: (i) epiphytic local stem-scale diversity declined, (ii) there was a loss of late-successional species including foliose cyano- and tripartite lichens and bryophytes and (iii) stem sizes were reduced, providing a further limit to the accumulation of species richness within a site.

Conclusions: Relict hazelwoods in western Scotland are confirmed as an example of the most intact epiphyte communities. In particular, we show that the transition to coppicing can be clearly linked to ecological processes causing species loss.     

On the importance of habitat continuity for delimiting biogeographic regions and shaping richness gradients

The formation and maintenance of biogeographic regions and the latitudinal gradient of species richness are thought to be influenced, in part, by the spatial distribution of physical habitat (habitat continuity). But the importance of habitat continuity in relation to other variables for shaping richness gradients and delimiting biogeographic regions has not been well established. Here, we show that habitat continuity is a top predictor of biogeographic structure and the richness gradient of eastern Pacific rocky shore gastropods (spanning c. 23 000 km, from 43°S to 48°N). Rocky shore habitat continuity is generally low within tropical/subtropical regions (compared to extratropical regions), but particularly at biogeographic boundaries where steep richness gradients occur. Regions of high rocky shore habitat continuity are located towards the centres of biogeographic regions where species turnover tends to be relatively low. Our study highlights the importance of habitat continuity to help explain patterns and processes shaping the biogeographic organisation of species.