Effects of Forest Management on Beetle (Coleoptera) Communities in Beech Forests (Fagus sylvatica) in the Apennines of Central Italy (Tuscany (original) (raw)
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Forest Ecology and Management, 2014
European beech forests are of particular importance for biodiversity, although relatively little is known about how beech forest management impacts on invertebrate communities. In this paper we investigated the influence of beech forest management history [i.e. over-mature coppices (OC) and coppices in conversion to high forests (CCHF)], climatic, topographic and microhabitat characteristics on ground beetle diversity (measured as total relative abundance, species richness, Shannon diversity and abundance of the endangered endemic species Carabus olympiae) in northern Italy. The diversity of forest specialist carabids was higher in OC and in forest stands characterized by a higher mean temperature and lower relative humidity. Moreover, we detected a positive response of several diversity variables to coarse wood debris cover or volume, herb cover, and the standard deviation of tree diameter. Currently, OC seems to be a more favorable habitat for forest carabids, including C. olympiae, although succession over time can lead to a progressive homogenization of the vegetation structure, with negative consequences for the conservation of the forest carabid assemblage. Based on our results, we suggest that the traditional management of beech coppice and its conversion to high forest be modified by including practices aimed at promoting structural and microhabitat diversity such as retention of large trees, creation of canopy gaps, retention of coarse wood debris and the preservation of ‘islands’ of older trees in the managed stands.
Effects of forest management on ground beetle diversity in alpine beech (Fagus sylvatica L.) stands
Forest Ecology and Management, 2014
European beech forests are of particular importance for biodiversity, although relatively little is known about how beech forest management impacts on invertebrate communities. In this paper we investigated the influence of beech forest management history [i.e. over-mature coppices (OC) and coppices in conversion to high forests (CCHF)], climatic, topographic and microhabitat characteristics on ground beetle diversity (measured as total relative abundance, species richness, Shannon diversity and abundance of the endangered endemic species Carabus olympiae) in northern Italy. The diversity of forest specialist carabids was higher in OC and in forest stands characterized by a higher mean temperature and lower relative humidity. Moreover, we detected a positive response of several diversity variables to coarse wood debris cover or volume, herb cover, and the standard deviation of tree diameter. Currently, OC seems to be a more favorable habitat for forest carabids, including C. olympiae, although succession over time can lead to a progressive homogenization of the vegetation structure, with negative consequences for the conservation of the forest carabid assemblage.
The awareness of the importance of deadwood in forest ecosystems has increased in recent decades. Today, dead wood is recognized as a key factor affecting diversity of forest communities. Hole-nesting birds and saproxylic organisms represent an active part of the animal community through the recycle of decaying wood into the forest soils. Three relict beech forests of central Italy were surveyed for both saproxylic beetles and hole-nesting birds, using two different types of interception traps for the former group and point count method for the latter. The variables of dead wood quality were recorded from ten plots, particularly the decaying class and typology of all the wood debris with a diameter ≥ 5 cm. In order to correlate richness and abundance of beetles and birds in a symmetric way, we used co-inertia analysis (CoIA). To correlate in a predictive way the dead wood attributes (dead wood typology and class decay) with birds and beetles assemblages we used partial redundancy analysis (RDA). Our results showed a significant relationship between saproxylic beetle and hole-nesting bird communities. Three dead wood variables (the volume of standing dead trees, stumps and large branches on the ground) appeared to be good predictors of saproxylic beetle richness while the volume of standing dead tree and of dead trees on the ground were the same for hole-nesting birds. These results suggest specific recommendations useful for forest management and planning.
Survey of saproxylic beetle assemblages at different forest plots in central Italy
Saproxylic beetles from coarse deadwood debris found on the forest floor were documented for the first time at four permanent monitoring plots in central Italy that are part of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The plots consisted of unmanaged vegetation communities representing typical beech forest, mixed broadleaf and conifer forest, Turkey oak forest, and cork oak forest respectively. With the present study, we identified beetle assemblages to species level and investigated whether the type of vegetation affects beetle communities. In order to detect more of the species present and perform a better comparison among study sites, samples were collected with two types of traps: flight interception traps hanging from tree branches (n = 1 per plot) and emergence traps mounted on deadwood like fallen branches or trunks (n = up to 8 per plot, depending on the availability of deadwood pieces). A total of 1372 individual beetles, belonging to 133 species of 36 families were captured, identified and enumerated. Considering all beetles caught in both trap types, alpha-diversity values indicated high beetle diversity at all of the four forest sites, while measured species richness, accumulation curves and species richness estimators agreed that the highest species density was at Rosello. Monte Rufeno had the highest abundance of beetle individuals. Monte Rufeno and Monte Circeo had the highest numbers of saproxylic species, even though Rosello had the highest total number of beetle species. Ninety species (67.7% of the species found in all plots combined) were caught in only one plot, while only three species, representing 2.3% of the total of species, were collected at all of the four plots; nine saproxylic species were collected exclusively at Monte Circeo, among them rare singletons like Agrilus convexicollis mancini Obenberger (Buprestidae) and Nematodes filum (F.) (Melasidae), the latter recorded in central Italy for the first time. Environmental variables having the strongest correlations with the assemblage composition were plot-scale variables (slope, stand age, amount of deadwood). The only trap-scale variable that showed up as related to assemblage composition was wood decayclass. The study highlighted that the diversity in saproxylic beetle communities reflects the different tree communities at the four study plots. The research also showed that even at the small and very small scale of forest plots, traits of beetle assemblages can be revealed on coarse deadwood debris.
Research on changes in biodiversity due to the abandonment of forestry is important in understanding the role of reserves in conservation. The aim of this study was to investigate whether changes have occurred in species richness, abundance and composition of ground, longhorn and bark beetles due to habitat changes as a result of the cessation of forest management. We surveyed ten managed and ten abandoned forest plots in two watersheds located in the north-eastern Italian alpine region, which share a common history of use, climate regimes, stand structure and topography. Ground beetles, and longhorn and bark beetles were collected with pitfall and flight-intercept window traps, respectively, from May to mid-October 2010. The three beetle taxa responded differently to changes in habitat features and management cessation. Differences in individual species responses between the two watersheds may indicate a role of management abandonment through its impact on forest habitat structure. For instance, ground beetle species mainly responded negatively to soil moisture and positively to understorey vegetation cover. Unexpectedly, saproxylic species re- sponded variably, and often negatively, to deadwood fea- tures in these forests, but did respond positively to the volume of standing Abies alba trees. The assemblages of carabids and bark beetles differed between the two water- sheds. Our results confirmed that 50 years of forest man- agement cessation resulted in changes in the biodiversity of beetles in alpine forests, likely due to their response to changes in habitat structure. Moreover, we expect that where the unplanned abandonment of forestry practices and habitat rewilding are undergoing, like in many mar- ginal areas of Europe, similar habitat structure dynamics and beetle responses are likely to occur spontaneously.
Ecological Indicators, 2020
Beetle communities are excellent indicators to monitor biodiversity in forest environments. The most common indicators monitored for assessing the effectiveness of the sustainable forest management measures are deadwood amount, forest structure, and microhabitat traits. In Mediterranean mountain forests, however, the relationships between stand-level attributes and species diversity indicators have been still poorly studied. We have investigated the patterns of species diversity of beetle communities in relation to stand structural traits in two unmanaged forests located in central Apennines (Italy). The two forest stands are characterized by different tree species composition and management history. The experimental area extends over approximately 300 ha, within which 50 circular plots of 530 m 2 were sampled for each studied forest. Coleoptera were collected using window flight traps and emergence traps on decaying deadwood. We evaluated i) the differences in species diversity (richness, Shannon diversity and Simpson diversity) between the two forests and ii) the beetle Shannon diversity and composition in relation to selected forest variables, with a particular focus on saproxylic species. Principal Component Analysis followed by rarefaction analysis were applied to examine differences in species diversity. Within each forest stand, a Boosted Regression Tree model and a Non-Metric Multidimensional Scaling were performed to relate the species Shannon diversity and community assemblages to the forest structural attributes. Results revealed how these forest structural attributes have a fundamental role in influencing the diversity of Coleoptera and their assemblages. Forest vertical heterogeneity, snag volume and tree dominance were the most important variables for saproxylic assemblages in these Mediterranean mountain forests, while the amount of coarse woody debris positively affected the overall beetle diversity and that of saproxylic species. At stand level, differences in species diversity were mainly driven by tree composition, probably indicating that food resources, determined by tree species, are of primary importance in determining species assemblages and beetle diversity in these forests; while at plot level, we found that the variables, which drove species composition and beetle diversity, varied between the two forests. This study provides the basis for the integration of independent biodiversity indicators in sustainable solutions for the conservation of unmanaged forests in Mediterranean mountain systems. 2008). The current distribution and structure of forest ecosystems in the Mediterranean region is the legacy of centuries of forest use and landscape transformation. Forest exploitation and landscape degradation have also influenced the presence of endemisms and, more in general, the biodiversity occurring in mountainous areas of the Mediterranean
Journal of Insect Conservation, 2009
The carabid beetle species assemblages (14 sample sites) of a 238 ha urban oak forest in Trieste, Italy, studied in 1983–84 with pitfall traps, were compared with an historic list of 57 species hand collected by entomologists in the same forest before it was logged in 1944.Trap data have been improved by hand collections to get a species list as complete as the historic one. Multivariate analysis was used to group the sites (14 plus the historic list) into three assemblages of brooks, clearings and forests. After the Second World War logging, the secondary ecological succession resulted in a lower species number, with a trend to a new equilibrium. Some important forest specialists, such as Laemostenus venustus, have been lost. Human pressure and recolonisation by carabids are still occurring. The in situ extinction of ground beetles near the end of the last century reached values between 57 and 64% of the species historically recorded. Consequently, urgent restoration measures are required for waterside habitats, forest and land management, to maintain small open areas or clearings. The study of carabid species assemblages and habitat affinities seems a useful tool for adaptive management of forests affected by human activities, because changes in carabid species number and type can be easily related to human disturbance.
Spatio-temporal analysis of beetles from the canopy and ground layer in an Italian lowland forest
Bulletin of Insectology, 2014
Canopies of temperate forests are still largely unexplored and the biodiversity they harbor is still poorly known, even for Coleoptera, the most studied insect group. In a lowland forest in northern Italy, Malaise traps were set in the canopy (n = 7) and ground layer (n = 7) and eleven beetles families (Buprestidae, Eucnemidae, Throscidae, Elateridae, Cantharidae, Dasytidae, Malachiidae, Tenebrionidae, Cerambycidae, Anthribidae, and Scolytidae) were compared for species richness and similarity of assemblages. Additionally it was investigated if species were associated with the forest layers studied and which of the families best qualified as bioindicator taxon. Finally, it was analyzed if similarity between the two layers was affected by season. The beetle assemblages in the two layers were significantly different, but species richness was similar. Eight species were significantly associated with the canopy and 15 species with the ground layer; for 16 of these this association is reported for the first time. Cerambycidae characterized the differences between ground and canopy best, as assemblages of this taxon were well separated; and these were significantly related to the composition of all families considered. Season had a strong influence on the trapping results and the dissimilarity of beetle assemblages between canopy and ground layer was most pronounced between late May and late July. This study showed that the distribution of beetles in the forest is structured in time and space and that season influences the capacity to distinguish between beetle assemblages sampled in the canopy and at the ground.
Journal of Insect Conservation, 2008
Compared to agricultural land and spruce plantations, central European beech-oak forests are often relatively close to natural conditions. However, forest management may alter these conditions. In Steigerwald, southern Germany, a large beech-dominated forest area, three management intensities were applied during the past 30-70 years. Here, we examined the influence of management intensity on saproxylic beetles in >100-year old mature stands at 69 sampling plots in 2004. We sampled beetles using flight-window traps and time standard direct searches. The community structure based on presence/absence data changed remarkably along the gradient from unmanaged to low-intensity to high-intensity management, but these differences were not evident using abundance data from flight interception traps. Saproxylic species richness decreased in intensively managed forests. Elateridae and threatened species richness peaked in unmanaged forests and in forests under low-intensity management. Saproxylic species richness was dependent on certain micro-habitat factors. These factors were (1) the amount of dead wood for Elateridae, overall and threatened saproxylic beetle richness; (2) the amount of flowering plants for Cerambycidae; (3) the richness of wood-inhabiting fungi for Staphylinidae, Melandryidae and overall saproxylic beetle richness; and (4) the frequency of Fomes fomentarius for threatened species. Species richness was better explained by plot factors, such as dead wood or fungi, than by management intensity. These results suggest that the natural variation of dead wood niches (decay stages, snag sizes, tree cavities and wood-inhabiting fungi species) must be maintained to efficiently conserve the whole saproxylic beetle fauna of beech forests. Also, intensive management may alter the specialised saproxylic beetle community even if the initial tree-species composition is maintained, which was the case in our study. For monitoring the ecological sustainability of forest management we must focus on threatened species. If structures alone are sampled then the amount of dead wood is the best indicator for a rich saproxylic beetle fauna.