1,720,974 research outputs found
The impact of management practices and past demographic history on the genetic diversity of italian wild boar (sus scrofa)
No full textVariazioni cromatiche nel geco (Tarentola mauritanica): causalità diretta e adattamenti evolutivi
No full textGenetic factors implied in melanin‐based coloration of the Italian wall lizard
Full text linkAs largely demonstrated for a wide range of vertebrates, the melanin‐based coloration can be the effect of both mutations in the melanocortin‐1 receptor (MC1R) gene and of differential expression of the same gene. However, in lizards, this mechanism is poorly known and some populations exhibit a high variation of melanism. Some populations of Podarcis siculus show a gradual melanization, suggesting a case of a quantitative phenomenon rather than a qualitative one. Here, we objectively quantify the continuous colour variation by spectrophotometric analysis demonstrating that the changes in the skin reflectance are not associated to mutations in the coding region of the MC1R gene but seem to be related to a concomitant variation of expression for this gene
WILD BOAR INVASION TREATS BIODIVERSITY IN MEDITERRANEAN NATIONAL PARKS
No full textThe Wild Boar (Sus scrofa) is the most-widely distributed ungulate of the world. Since
the 1960s, wild boars went through a worldwide population expansion that increased
their overall geographic distribution as well as their population density in many areas
in Europe. For example
studies documented an increase of wild boar hunting bag by
540% during 1960
-
2002 in Northern Germany, meanwhile in France by 500% during
the 1973
-
1993, and in the next five years by an additional 900%. The widespread
increase in numbers and geographica
l range of this species might have a remarkable
impact on many plant communities and animal species, habitat structure and crop and
livestock production. The Cilento and Vallo di Diano National Park has instituted in the
1995 in the hotspot of Mediterranea
n region. From this period the administration of
Park has refunded, to the local communities, some of the damage declared for the
agricultural or traditional manufacture constructions imputable to wild boar actions.
Just at the end of 2009 National Park go
vernance started an organic plan to manage
the wild boar problem, in collaboration with University of Naples Federico II. Here we
report this action plan, arisen from an interdisciplinary approach in consideration of all
the components that are associated
to this problem. We developed simulation of
population dynamics in the national park, as well as to verify the effectiveness of the
management operations in progress throughout the action planed. We analysed the
population genetic characteristic, in the li
ght of European wild boar phylogenesis and
human translocation, hybridization with the domestic form and their effect on the wild
populations. We evaluated also population structure arising from this overpopulation.
The lack of natural predators, the eleva
ted environmental plasticity, and peculiar
reproductive biology of some hybrid populations would seem concomitant causes of
the high density both in natural and anthropic areas. Moreover wild boar ecological
invasion can create problem to some critical spe
cies like as orchids, birds nesting on
ground (i.e.
Alectoris graeca
) or lizards (
Podarcis sicula
). Wild boar problem involves
progressively many protected areas in Italy and the divulgation of a scientific
management can represent key factor for an
organic approach and a prompt for
research in conservation biology
HISTORICAL CHANGES OF LANDSCAPE AFFECT POPULATION SIZE AND CONNECTIVITY OF ITALIAN ROCK PARTRIDGE
No full textAfter the Second World War, agro
-
pastoral practices in
Italian mountain areas were
progressively abandoned due to the
development
of industry and intensive crop.
Human depopulation of rural mountain areas
and the consequent abandonment of
traditional land management are among the
greatest driving forces behind changes in
this ecosystem in whole Western
Europe. This change
involves a specific ecological
succession, in which
grassland gradually turns into scrubland and, ultimately, into
forest,
increasing in agro
-
pastoral landscape fragmentation, reducing patches size
and increasing in mutual distance. The animal associated
with agro
-
pastoral
habitat
may suffer from decreased connectivity as a consequence. The Rock
Partridge
(
Alectoris graeca
) is a mountain species endemic to Europe here
used as a model for
investigating the impact of habitat loss, fragmentation,
hunting and
climate change.
We compared the habitat suitability of the
Apennine Rock Partridge prior
to
abandonment of traditional agro
-
pastoral
activities with the current landscape, in
order to investigate the effect of
secondary succession on the distribution and v
iability
of the species. We
aimed to understand the type and extent of habitat loss that the
Apennine
population has experienced. We assessed the past landscape throughout
historical aerophotography an
d species distribution (c. 1900
-
1950) by
quantifying
anecdotal evidence from interviews. Current landscape and
distribution were assessed
from GIS resource and survey data respectively.
We applied ecological niche factor
analysis and connectivity approaches to
obtain historical and current Rock Partridge
hab
itat suitability. Results
indicated that in just five decades our study area has
experienced profound
changes in landscape structure and function. We observed a
drastic decrease
in connectivity as a result of a reduction in numbers and size of high
suitabi
lity patches. We suggest
to maintain a viable populatio
n it
requires an ensemble
of ecological conditions along corridors connecting the
actual residual populations. In
the Rock Partridge, we also showed that,
during this time period, species experienced
a
shift of niche and an
increase of marginality. However, if
the increased population’
s
fragmentation recorded since the 1900s persists, the
extinction of some of
the
subpopulations appears inevitabl
Landscape fragmentation and interspecific interaction can affect status of Italian hare
No full textHabitat fragmentation, caused by expanding of human activities through landscape,
has heavy effects on the status of natural populations. It causes: the reduction of total
biodiversity, the loss of reactivity of the whole ecosystem, and the increase of
ecological distances between populations. During the last decade, the endemic Italian
hare (Lepus corsicanus) shows a endangered conservation status due to the
fragmentation and scarcity of its populations. Globally, this species is classified as
vulnerable due to its variable conservation status across its restricted
geographic range. Italian hare decreasing can be also imputable to others different
factors: harvest, poaching, and the probable interspecific competition with congeneric
European hare (Lepus europaeus, introduced in the last decades by man for hunt).
However, the creation of several protected areas in southern and central Italy will help
the populations to recover. The goal of our work was provide a descriptive model to
explain actual distribution of Italian hare in relation to landscape fragmentation
and interaction with sympatric European hare. In order to suggest starting
point for management actions in the conservation planning of Italian hare. Cilento and
Vallo di Diano National Park is home of the greater population of Italian hare, of
peninsula, and here we validated ecological model and populations genetic analysis
from two species. Genetic approach can be a good tool to quantify status, probable
hybridisation, and dispersal, especially if it can be correlated with the connectivity of
the landscape. The results suggest that the Italian hare shows an ecological
requirement close to average of available resources in the considered landscape. The
genetic structure of this autochthonous species can be explained from habitat
suitability pattern, and it highlights the differences between the two species. By our
first results we can not exclude the inter specific hybridisation events. A lot of
conservation actions can be carried out to improve connectivity between Italian hare
subpopulations actually characterised by low gene flow: finding new corridors or
moving artificially the hare populations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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