Corresponding author: Umberto Maritano (
Academic editor: Torsten Dikow
Merlino Wood is a typical oak–hornbeam forest in the Po Plain hydrographic region. It is one of the few remaining lowland forests in Northern Italy and is a Regional Natural Reserve and a Site of Community Interest (code IT1160010). This is the first survey on hoverflies in the study area and they act as bioindicators to assess habitat conservation. Sampling was performed with three Malaise traps and an entomological net. A total of 61 species of
The Merlino Wood Natural Reserve (MWNR) is an oak–hornbeam forest located in the Po Plain hydrographic region (Northern Italy). It is a Regional Natural Reserve and a Site of Community Interest (SCI; code IT1160010). The oak–hornbeam woods are considered of high ecological value and, for this reason, are listed as a habitat of European interest according to Directive 92/43 EEC (
The MWNR has been repeatedly investigated for its
In order to assess ecosystem conservation, it is very important to organise sampling activities to standardise monitoring (
Merlino Wood (Fig.
In order to include all phenological periods of adult
The use of Syrph the Net (StN) as a tool to assess the natural conservation of ecosystems has been widely tested in Europe (e.g.
The study yielded 61 species sampled in the Merlino Wood Natural Reserve. Table
By applying Syrph the Net (including migratory species and using the Piedmont checklist as reference), the BDMF value in over-mature mesophilic
Microhabitats associated with old trees seem to be in very good conservation conditions (Table
Hoverflies are the main pollinators after
Conservation actions on saproxylic insects play a key role in the management of forest ecosystems (
From the conservation strategy viewpoint, it would be advisable to avoid planting intensive crops close to the forest. There should be a buffer zone of at least 50 m around the full whole perimeter of the wood, in addition to internal clearings, assuming harvesting at times that do not compromise the blooming of the grasses. This could also favour phytophagous species. Forest management should allow the possibility of indefinite growth of the oldest oaks, in order to support the greatest possible number of microhabitats. The average age of the oldest
Merlino Wood is subject to enormous human pressure, but still represents an isolated source of saproxylic organisms. Strict habitat conservation measures are required to preserve its flora and fauna.
I am grateful to Simon Piers Aiken for improvements to the English. Many thanks to Luca Cristiano and Daniele Sommaggio for precious comments and suggestions which they made on the manuscript. I would like to thank Monviso Park for giving me permission to sample in the study area. I sincerely thank the reviewers whose comments helped in improving the preliminary draft of the manuscript.
Position of Merlino Wood Natural Reserve in Italy, Piedmont Region in yellow.
Merlino Wood and the sampling area.
Typical ecotone at border to oaks of the Merlino Wood Natural Reserve.
Checklist of
Faunistic list | Malaise trap (N of specimens) | Net (N of specimens) | First observation month | Very low density |
1 | June | |||
1 | March | x | ||
1 | 1 | May | ||
1 | March | x | ||
1 | April | x | ||
1 | May | |||
2 | July | |||
1 | May | x | ||
1 | June | x | ||
1 | June | |||
1 | 2 | March | ||
1 | 1 | May | ||
1 | April | |||
1 | April | |||
2 | April | |||
1 | April | |||
1 | May | |||
4 | 1 | March | ||
3 | March | |||
1 | June | |||
1 | August | |||
3 | June | |||
1 | March | |||
3 | March | |||
7 | June | |||
1 | 2 | May | ||
1 | 1 | March | ||
2 | May | |||
4 | May | |||
1 | May | |||
17 | 1 | March | ||
2 | May | |||
2 | April | |||
2 | May | |||
1 | March | |||
6 | April | |||
1 | 3 | March | ||
3 | May | |||
1 | July | |||
2 | April | |||
1 | April | x | ||
4 | April | |||
5 | April | |||
12 | March | |||
1 | May | x | ||
1 | May | |||
1 | April | |||
2 | July | |||
1 | May | |||
1 | June | |||
2 | March | |||
4 | 3 | June | ||
1 | March | |||
19 | 3 | March | ||
1 | July | |||
1 | May | |||
1 | June | |||
1 | June | |||
20 | March | |||
1 | 2 | May | ||
1 | May | x |
Derivation of BDMF (Biodiversity Maintenance Function) percentage value for macrohabitat, based on Syrph the Net (StN).
Macrohabitat | CORINE Code | StN Code | Expected species (N) | Observed species (N) | BDMF (%) | Unpredicted species observed not migrant (N) |
Mesophilic |
41.2 | 11221 | 112 | 42 | 37.5 | 9 |
BDMF percentage value for trophic larval categories, based on Syrph the Net (StN). Exp.: Number of Expected species, Obs.: Number of Observed species
Macrohabitat | Xilosaprophagous | Phytophagous | Predators | Detritivores | ||||||||
Exp. | Obs. | % | Exp. | Obs. | % | Exp. | Obs. | % | Exp. | Obs. | % | |
Mesophilic |
28 | 15 | 53.6 | 23 | 4 | 17.4 | 49 | 20 | 40.8 | 12 | 3 | 25 |
BDMF percentage values for voltinism and larval microsites, based on Syrph the Net (StN).
Expected species (N) | BDMF (%) | ||
Number of generations/year | < 1 | 5 | 60.0 |
1 | 71 | 28.2 | |
2 | 46 | 41.3 | |
> 2 | 10 | 70.0 | |
Larval microsite | Foliage | 25 | 48.0 |
Stem bases | 11 | 18.2 | |
Grass-root zone | 14 | 50.0 | |
Bulbs/tubers | 10 | 30.0 | |
Mature trees | 33 | 48.5 | |
Timber stumps | 9 | 55.6 | |
Timber fallen | 4 | 75.0 | |
Timber standing | 5 | 60.0 | |
Trunk cavities | 17 | 58.8 | |
Sap runs/lesions | 18 | 44.4 | |
Nests of social insects | 5 | 60.0 | |
Submerged sediment/debris | 8 | 37.5 |