Giorgio Malacarne | Università degli Studi del Piemonte Orientale "Amedeo Avogadro" (original) (raw)

Papers by Giorgio Malacarne

Droughts and distribution of hyporheos: perspectives from the Po River (Natural Park of the Po Ri... more Droughts and distribution of hyporheos: perspectives from the Po River (Natural Park of the Po River) -In this study we analysed the role of hyporheic zone as refugium for the benthic macroinvertebrates in the high reach of the Po River (Parco del Po Cuneese -NW Italy). Aim of our study was to investigate the vertical distribution of macroinvertebrates within the stream substrate in the period Juny 2004 -December 2005. We positioned 12 hyporheic traps in the streambed. Each trap consisted in an outer structure containing three inside bags. The structures were buried in the streambed in June 2004 with a mini escavator Kubota and still remain in place. The inside traps were filled with clean sterile substrate, similar to the streambed composition, and placed at different depths: the top trap was positioned from 0 to 30 cm, the medium one from 30 to 60 cm and the bottom one from 60 to 90 cm. In this work we present our data about distribution, stratification and abundance of stream benthos within the substrate during the dry season in the period August 2004 -December 2005.

A b s t r a c t . Unusual climatic events are known to influence micro-evolutionary changes in bi... more A b s t r a c t . Unusual climatic events are known to influence micro-evolutionary changes in birds through selection and directional evolution of body size. In NW Italy a notable climatic episode occurred from 1984-85 to 1986-87 when the winters were unusually severe. In the periods 1986-88 and 1997-2000 we measured the body size and mass of

Steam disinfestation of soil is attracting growing interest in intensive agriculture, because of ... more Steam disinfestation of soil is attracting growing interest in intensive agriculture, because of the increasing demand of reduced use of fumigants. In this study, we assessed the effect of steam applica- tion on the microarthropod community, a fundamental component of soil environment. We conducted steam disinfestation treatments in ex- perimental parcels, where we sampled for edaphic microarthropods in one date

We analyzed song differences between adults and subadults of the Black Redstart (Phoeni- curus oc... more We analyzed song differences between adults and subadults of the Black Redstart (Phoeni- curus ochruros) breeding in the Western Alps and found differences both among individuals and between the two age categories. The-song parameters utilized for differentiation of individuals were different from those used for adults and subadults. A playback ex- periment simulating territory intrusion revealed that adults reacted more

Italian Journal of Zoology, 1999

Sexing individuals in a population is important in many ecological and life‐history studies. Sinc... more Sexing individuals in a population is important in many ecological and life‐history studies. Since many bird species are monomorphic, non‐invasive tools are necessary for sex determination. In this study we utilized flow cytometry to sex individuals in a moorhen population of northern Italy. By improving previous laboratory protocols, we were able to obtain clear and repeatable measures of DNA content

Limnologica, 2007

The influence of streambed sediment clogging on macroinvertebrate communities was investigated in... more The influence of streambed sediment clogging on macroinvertebrate communities was investigated in the Lemme creek (NW Italy). To assess how fine sediment accumulation can influence the colonisation process and community composition of macroinvertebrates, we placed 48 traps in the riverbed. The traps consisted of boxes built with metal net (mesh 1 cm, height 15 cm, sides 5 cm) covered with nylon net except for the apex, allowing access exclusively from the top. We created four trap types filled with 100% gravel, 30% sand and 70% gravel, 70% sand and 30% gravel and 100% sand. After 20 and 40 days, we removed 6 traps/type. Macroinvertebrates rapidly colonised the traps, as we found no significant community differences between the two removal dates. Among the four trap types, we found significant differences in taxa number and abundance, which both decreased with increasing clogging. Thus, our study supports the hypothesis that clogging and the accumulation of fine substratum elements strongly affects benthic stream communities.

Behavioural Processes, 2006

Carotenoids are important for various functions during chick development. Since these pigments ca... more Carotenoids are important for various functions during chick development. Since these pigments cannot be synthesized, they can be considered limited resources that the mother optimally allocates between herself and her offspring (maternal effect). Some studies have examined the effects of carotenoids on growth and immune function but little is known about their role in behaviour. In this study of the

Journal of Ornithology, 2002

Little is known about indices of health condition in free-living populations and particularly abo... more Little is known about indices of health condition in free-living populations and particularly about the presence of significant fluctuations of these indices between years. We assessed blood and immunological condition in wild Hooded Crows (Corvus corone cornix) in NW Italy for three years (1997)(1998)(1999). Crows did not show any year-to-year difference in erythrocyte sedimentation rate, leukocyte abundance, and heterophyl/lymphocyte ratio. In contrast, we observed significant annual differences in albumin and immunoglobulin values. The albumin/immunoglobulin ratio was lower in 1998, a year when the size of two immunocompetence organs (bursa of Fabricius and spleen) was also smallest. Neither population density nor climate were likely to affect the observed variation of immune condition, annual censuses not revealing any noticeable density variation during the study period, and rainfall and mean temperatures being similar. The results show that in natural populations between-year variation of immune condition may exist, and that in our study, species immunoglobulin assays were more effective than leukocyte counts to detect them.

Italian Journal of Zoology, 2010

There is much evidence that climate is rapidly changing at a global scale, especially regarding m... more There is much evidence that climate is rapidly changing at a global scale, especially regarding mean annual temperatures, precipitations and evaporation. The consequences of this rapid environmental change on freshwater biota are still not clear, but undoubtedly they could be severe. Among the main effects of climate change, we can individuate the enhancement of water temperatures, particularly important for poikilothermic organisms, with the consequent diminution of dissolved oxygen, and the reduction of available habitats for most stenothermal organisms. Another consequence of climate change is the alteration of hydrologic cycles, with increasing intensity and frequency of extreme events such as droughts, especially in Southern Europe. This scenario could severely affect freshwater biota, especially in mid-latitude regions, such as the Italian peninsula: shifts in phenology, life cycles and distribution ranges are likely to be expected for many organisms, with the extinction of many sensitive species. In particular, species adapted to perennial and cold waters are likely to suffer reductions in their distribution range and also local extinctions, while more tolerant organisms may enlarge their distribution ranges. Global climate change may also promote and enhance invasions of alien species. In this work, concepts and hypotheses about the presumable impacts of climate change upon freshwater biota are reported, with examples and predictions related to the Italian situation.

Italian Journal of Zoology, 2001

Only recently have there been attempts to assess the short-term variations of indices of body con... more Only recently have there been attempts to assess the short-term variations of indices of body conditions and immunocompetence in free-living populations, and to evaluate the presence of significant fluctuations of these indices between years. We compared body conditions and size of immunocompetent organs (spleen and bursa of Fabricius) in wild populations of hooded crows in NW Italy during three years. Differences in population density among sites did not influence any of the variables, while a great difference was found between adult and subadult birds. In the study period, adults did not show any year-related variation of mass, structural size, lean mass (as assessed by TOBEC electroconductivity index), and spleen mass. Instead subadults of both sexes showed differences among years in mass; subadult females had the lowest values of bursa and spleen mass in the year when mass was smallest. The results show that in natural populations between-year variation of body conditions may exist. Subadults are probably most sensitive to adversities producing short-term variations in body conditions.

Italian Journal of Zoology, 2007

In the rivers of northern Italy, the presence of water is typically continuous all year long, alt... more In the rivers of northern Italy, the presence of water is typically continuous all year long, although in the last five decades there has been a conspicuous increase in drought periods, mainly caused by human impacts and climate change. The aim of this study was to assess the impact of the length of the drought periods on macroinvertebrate assemblages. We collected invertebrates in four reaches of the Po river, characterised by different periods of absence of surface water. We found significant differences among the stations in invertebrate abundance and taxa richness, with a decrease in the more droughtaffected stream reaches. Collector-gatherers significantly increased as the drought period lengthened, while the opposite occurred for scrapers and shredders. The areas with a discontinuous presence of water were mainly colonised by small, fastgrowing, plurivoltine organisms. A main result of our study is that only a few taxa appear to be able to survive in reaches with intermittent flow, underlining the great ecological difference between perennial and naturally intermittent streams. Our results suggest that the recent increase of droughts will likely cause an impoverishment of benthic communities in prealpine rivers.

Italian Journal of Zoology, 1996

Abstract The reproductive activity of swifts is affected by seasonal fluc tuations of aerial inse... more Abstract The reproductive activity of swifts is affected by seasonal fluc tuations of aerial insects which are largely unpredictable, depending day by day on climatic conditions. In this work we investigated whether the parental food provisioning is influenced by hourly fluc ...

Bolletino di zoologia, 1986

... G. Allegrucci, M. Lucarelli, V. Sbordoni, P. Pecora, B. Cicolani, R. Cianchi, M. Corti, CM Ci... more ... G. Allegrucci, M. Lucarelli, V. Sbordoni, P. Pecora, B. Cicolani, R. Cianchi, M. Corti, CM Ciabatti, E. Capanna, P. Deri, F. Dim, P. Giubbilini ... stirpi della Corsica: Paradojo, diploi de (2n=16;n=8) nelle linee somatica e germinali e Roccapina, triploide nella linea somatica, esaploide ...

Israel Journal of Zoology, 2001

... HOODED CROW CAMILLA ACQUARONE, MARCO CUCCO,* AND GIORGIO MALACARNE Department of Sciences and... more ... HOODED CROW CAMILLA ACQUARONE, MARCO CUCCO,* AND GIORGIO MALACARNE Department of Sciences and Advanced Technology, University of Eastern Piedmont, via Cavour 84, I-15100 Alessandria, Italy In ecological ...

Hydrobiologia, 2006

We examined vertical migration and colonisation patterns of stream macroinvertebrates within the ... more We examined vertical migration and colonisation patterns of stream macroinvertebrates within the substratum of an Apennine creek in NW Italy. Macrobenthos was sampled at three depths in the streambed (0-5, 5-10, 10-15 cm) by means of artificial baskets filled with natural substratum. We placed 42 traps (5Â5Â15 cm), i.e. 21 top-opened (T-traps) and 21 bottom-opened (B-traps), each composed of three overlapping baskets (high-H, medium-M and low-L), to evaluate differences in the vertical movements. We also collected Surber samples to compare interstitial assemblages with streambed communities. The multilevel traps yielded 42 taxa, compared with 60 taxa in the natural riverbed. Interstitial traps were rapidly colonised; both taxa richness and organism number increased during the 42-day study period. We found active migration in both vertical directions, but there were more invertebrates in the top-opened traps than in the bottom-opened traps. In the T-traps the most colonised baskets were those placed at the H level, while in the B-traps the L level baskets were more rapidly colonised. The interstitial assemblages differed markedly from the streambed communities in both composition and functional organisation, with more collector-gatherers and predators in the interstitial zone and more filterers and scrapers in the natural riverbed. In Apennine lotic systems, the interstitial zone is an important habitat for stream macrobenthos, although it may not be used by all species.

Hydrobiologia, 2010

Abstract Vertebrate carrions, in particular fish, can provide a significant source of organic mat... more Abstract Vertebrate carrions, in particular fish, can provide a significant source of organic matter to lotic systems. Most studies related to animal matter degra-dation have been undertaken in Western North Amer-ica, where entire lotic networks depend on large masses of ...

General and Comparative Endocrinology, 2008

Early maternal effects in the form of substances accumulated in the egg, such as carotenoids and ... more Early maternal effects in the form of substances accumulated in the egg, such as carotenoids and hormones, can be physiologically relevant for a good development of offspring. It has been found in different species that testosterone (T) can be beneficial to offspring by increasing growth rate, but detrimental by reducing immunocompetence and increasing oxidative stress. Carotenoids on the other hand are suggested to be beneficial because they can counteract the oxidative stress and the immune-depressive effect of T. In this study we analyzed the effect of prenatal T exposure in the grey partridge. We injected eggs with three doses of T (high, intermediate, and physiological). After hatching, chicks exposed to a prenatal high dose of T were fed with two diets (rich or poor) differing in b-carotene content. We found a significant effect of T on both chick growth and cell-mediated immunity, with high T doses resulting in detrimental effects while low doses were beneficial. Detrimental effects of the high dose of T on immunity were mitigated by b-carotene consumed in the diet. The differences between groups were observed in the early period of life (age 10 days for mass, and age 10 and 21 days for immunity), and disappeared in the following period, and up to 1 and 2 years later. Overall, our observations show that T in the egg is not detrimental but beneficial, and that negative effects are found only at supraphysiological concentrations. The negative effects of T on immunity could be balanced if chicks could consume a diet rich in b-carotene.

Ethology Ecology & Evolution, 2004

Parasites have the potential to be important forces driving the evolution of honest signals (e.g.... more Parasites have the potential to be important forces driving the evolution of honest signals (e.g. visual communication in the context of sexual selection) because they can affect the expression of colours in the host. Birds are affected by a variety of parasite taxa, but despite their acknowledged importance in epidemics, the role of bacteria in sexual selection in birds has been poorly investigated. In this study, we examined the expression of colours (red and yellow) in the frontal shield of Moorhens and compared the results with the cloacal bacterial presence. We also measured several health parameters (body condition, PHA immune response, heterophils/lymphocytes ratio, haematocrit) that could be related to the expression of frontal shield colour. We found a negative correlation between frontal shield redness and bacterial presence, but red colouration was not related to any other health index. In contrast, the colouration of the yellow portion of the bill was positively related to health (haematocrit and H/L ratio) and immune (PHA) parameters, but not to bacterial presence. These correlational data are consistent with the recent hypothesis that different kinds of colouration within an individual may provide different units of information. In the Moorhen, the frontal shields could act as a twofold honest signal of health status, where red reflects cloacal bacterial presence and yellow is related to blood parameters.

Ethology Ecology & Evolution, 2002

Carotenoids have attracted the attention of behavioural ecologists because of their modulatory ef... more Carotenoids have attracted the attention of behavioural ecologists because of their modulatory effects on the immune system, colour expression and several physiological functions affecting body conditions. To evaluate whether carotenoid abundance influences growth, behavioural performance, immunocompetence and bill colour, we raised two groups of Moorhen chicks for 1 month with different food intakes (control diet versus carotenoid-rich diet). The two