Assessing habitat-related disturbance in bird communities: Applying hemeroby and generalism as indicators

We tested the application of the concept of hemeroby and generalism at community level, on a set of birds occurring in various habitats of central Italy characterized by different level of disturbance. In each habitat-related bird community, we applied the recently published species-specific score in hemeroby (a proxy of habitat-related disturbance; HSi) and hemerobiotic diversity (a proxy of generalism; H’Hi) to local species frequency, obtaining weighted values at community level (HStot and H’Htot). The relationship between HStot vs. H’Htot showed an increasing trend moving from reed beds through forests and mosaics to urban communities. Quadratic model (best fit) evidenced a significant correlation between these variables and a tendency toward a hump-shaped curve, corroborating results already observed at species level (intermediate generalism hypothesis). The co-inertia analysis discriminated four groups of habitat-related communities, characterized by species with different levels of disturbance-sensitivity (expressed by HSi) and generalism (expressed by hemerobiotic diversity; H’Hi): (i) forest type-related, where mature wood communities were separated from a coppiced wood one; (ii) communities of moderately disturbed agricultural habitats; (iii) communities embedded in highly disturbed mosaics, and (iv) a group including either a highly disturbed urban habitat or a low disturbed wetland reed bed, with highly specialized species (respectively, synanthropic species and water-related species). Total scores in hemeroby and hemerobiotic diversity, expressing the composition in species with different disturbance preference and generalism, might act as good community-based indicators of degree of naturalness, especially for forest habitat types

A first assessment of genetic variability in the longhorn beetle Rosalia alpina (Coleoptera: Cerambycidae) from the Italian Apennines

The Rosalia longicorn (Rosalia alpina) is a strictly protected saproxylic beetle, widely distributed in Central and Southern Europe and mainly associated with ancient beech forests. To improve knowledge about the conservation status of R. alpina in Italy, available molecular markers (microsatellites and mitochondrial cytochrome c oxidase I(COI)) were tested for the first time on Italian populations. The study was performed in four sampling sites distributed in two areas placed in Northern (“Foreste Casentinesi” National Park) and Central Apennines (“Abruzzo, Lazio and Molise” National Park) where populational data about Rosalia longicorn were collected in the framework of the European LIFE MIPP Project. The genetic relationship among Apennine and Central/South-eastern European populations was explored by a comparison with mitochondrial DNA (mtDNA) data from literature. Microsatellite markers were only partially informative when applied to R. alpina Italian individuals, although providing some preliminary indication on an extensive gene flow among populations from the Apennines and local ongoing processes of genetic erosion. Genetic data are consistent with previous ecological data suggesting that the maintenance of variability in this species could be related to both habitat continuity and preservation of large senescent or standing dead trees in forests. Finally, a peculiar origin of the Apennine populations of R. alpina from a putative “Glacial Refugium” in Italy was inferred through COI data. The high genetic distance scored among the analysed populations and those from Central and South-eastern Europe indicates that the R. alpina deme from Apennine Mountains might represent a relevant conservation unit in Europe. Further genetic analyses will allow assessing other possible conservation units of R. alpina and, thus, defining large-scale conservation strategies to protect this endangered longhorn beetle in Europe

Effect of spring water stress induced by fishery farming on two duck species Anas platyrhynchos L. and Anas crecca L. in a Mediterranean wetland

In a remnant wetland of Central Italy, we assessed the effect of water level changes induced by fishery farming activities (February–July) on the abundance of two duck species (mallard, Anas platyrhynchos and teal, A. crecca) during a two-years period: a “treatment” year (2004) when fishery farm activity was high and water level dropped, and a “control” year (2007) when it was inactive and water level increased. Abundance values of mallards and teals were significantly different in the two years, and showed a direct correlation with water level in both the species in 2004 but not in 2007. In both species, abundance was significantly lower in 2004, only in late spring (June–July), revealing their sensitivity to water stress. A higher water level in wetland in control year 2007 may favour teals and mallards in the study area, allowing respectively the permanent occurrence of the former (a locally wintering species) and a higher abundance of the latter (locally breeding and resident species). A higher water level in wetland channels with the flooding of the surrounding reed- and rush beds, may induce a larger area of suitable habitat, available for these duck species. These facts emphasized that water level changes due to human activities are key to year-to-year variation in duck abundance in Mediterranean wetland regions

Bird and beetle assemblages in relict beech forests of central Italy: a multi-taxa approach to assess the importance of dead wood in biodiversity conservation

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

Shape variation of mandible and head in Lucanus cervus (Coleoptera: Lucanidae): a comparison of morphometric approaches

The exaggerated male traits under sexual selection are widespread throughout the animal kingdom, including ornaments to attract mates and weapons to deter rivals. Many species of stag beetles show a considerable interspecific and intraspecific variation in mandible size and shape. In the present study we used traditional and geometric morphometric approaches, on live Lucanus cervus males, to study the intraspecific variation in mandible and head size and shape and to get evolutionary insights about the exaggerated weaponry of the European stag beetle. We found that the shape of these structures strongly depends on their size (centroid size) and body size (elytron length), outlining two different morphologies: small males with wide and rounded mandibles and less developed head edges and larger ones with slender mandibles equipped with fully developed teeth and wider head edges. These shape differences may be related to alternative mating tactics and behaviours in smaller and larger males. Head and mandibles show a great shape variation, indicating that they can be considered as a functional unit, evolved under influence of the same selective pressures. By comparing traditional to geometric morphometric approach, we concluded that reducing the complex mandible structure to a linear distance is an accurate representation of size. Contrariwise, male head size cannot be reduced to linear distances, as usually done for the genus Lucanus, hence a geometric morphometric approach is needed to describe at best the magnitude of its change

Overwintering ability and habitat preference of Morimus asper: a two-year mark-recapture study with implications for conservation and forest management

Morimus asper is a saproxylic longhorn beetle associated with mature forests. Its flightless condition makes its colonization of new trees in fragmented areas difficult. Our 2-year mark-recapture study revealed new information about the survival ability, population dynamics and habitat preference of M. asper in three beech forests of central Italy. Daily surveys were performed from May to July in 2013 and 2014, inspecting suitable trees for hosting the species. A low percentage of overwintered adults was observed for both sexes, with a very long lifespan: 282–409 days. Almost all individuals were recaptured on the tree of their first capture, and dispersal (20–451 m) was recorded only in thirteen individuals. Adult phenology showed two peaks of activity (middle of May and middle of June). Population estimates varied significantly according to site and year. Mean daily temperature affected recapture probability and total captures (optimal range of 15–26 °C). The species showed preference for huge lying trees, branches on the ground, a low percentage of debarked surface and high canopy closure. M. asper showed a high survival probability, but the few movements observed, combined with its flightless condition, suggest strongly that this species has a low dispersal ability, highly threatened by local fragmentation. Furthermore, almost all captures were made on the same tree, making this a “key tree” for population viability. Forest management techniques should retain many lying trees, abundant coarse woody debris and a dense canopy that ensures a ‘cooler’ temperature in the understory, favouring M. asper and its conservatio

Sexual dimorphism and allometry of secondary sexual character in Morimus asper (Coleoptera: Cerambycidae).

The longhorn beetle Morimus asper exhibits the typical sexual dimorphism of cerambycid beetles: males have longer antennae than females and the antennal length also varies greatly among males of the same population. This study explores the sexual dimorphism in M. asper and the scaling relationship between antennal length and body size in males. Our aim was to assess the allometric pattern of these two traits and their potential effects on individual eco-ethological features. Sexual dimorphism was observed in antennal length and in other morphological traits: males showed longer pronota and females larger and longer elytra, suggesting that males allocate more resources to the anterior body traits, while in females more resources are invested in the development of post-prothoracic body traits. The allometric relationship between antennal length and elytra length of males was best described by a segmented regression, which identified a switch point dividing the male population into two different groups. The analysis of covariance showed that smaller males (with elytra length below the switch point) exhibit a positive allometry, while larger males (above the switch point) showed isometric scaling relationship. Our findings showed that morphometric traits were correlated with aspects of male behaviour and ecology: larger males were more frequently found mating, probably because they have an advantage in defending mates and in winning fights against other males

The importance of dead wood for hole-nesting birds: a two years study in three beech forests of Central Italy

This study explored the hole-nesting bird community for two years, in three beech forest stands of central Italy. Our experimental design involved 12 replicated sampling points in each study area for a total of 36 sampling points. Stand characteristics were measured through selected environmental variables (tree diameter, tree density, volume of dead wood, diversity of dead wood and canopy closure), to develop habitat models for describing the factors affecting the abundance of hole-nesting birds. We performed generalized linear models to determine which environmental variables better explained the presence and abundance of hole-nesting birds in the three study areas. The species that showed the highest values of abundance are the Nuthatch, the Blue Tit and the Great Tit. Within the guild of hole-nesting birds there are differences in the selection of suitable trees for nesting, roosting or foraging. Primary cavity nesters (woodpeckers) are mostly related to the presence of large trees, the volume of dead wood and tree height. The presence and abundance of secondary cavity nesters (tits, nuthatches and treecreepers) seem to be mostly influenced by diversity of dead wood. The diversity of dead wood is an important variable that influences the presence and abundance of hole-nesting birds. Maintenance of both living and standing dead wood in forest ecosystems is recommended to increase the effectiveness of conservation actions affecting the hole-nesting birds. © 2016 Informa UK Limited, trading as Taylor & Francis Grou