Dissertation committee:
Λεγάκις Αναστάσιος Αναπλ. Καθηγητής (Επιβλέπων), Πολυμένη Ρόζα- Μαρία Επίκ. Καθηγήτρια, Σφουγγάρης Αθανάσιος (Επίκ. Καθηγητής)
Summary:
The present study constitutes the first effort for the indirect total population
census of jackals in Greece, as well as the study of the species’ ecology in the
temperate zone.
The survey method was applied for the first time for jackals internationally
and it was tested for its effectiveness.
The body size alone does not give any clear division between 4 European
samples belonging to the same subspecies (Greece, Serbia, Romania, Hungary) and
the sample from Israel which belong to a different subspecies. Also from the
findings
seems that Bergmann Rule is not evaluated. Sexual dimorphism in body size was
observed in SE European jackals.
The dramatic decline of the golden jackal population in Greece from the '70s
until '90 was opposite to the population expansion that happened the same
period in
Central Europe and the Balkans.
All the locations with recent indication of jackal presence were surveyed at
selected calling stations, and minimum population estimates were recorded.
Afterwards the count of all jackal family groups took place. The applied
acoustic
census method includes broadcasted jackal howls, which were used to survey the
status of the golden jackal in Greece. With this method the minimum number of
territorial jackal groups was recorded.
Out of 264 sampling stations that were surveyed all over the country the
jackals responded positively in 131 (50%).
The results of the survey show that both populations and distribution area of
the golden jackal in Greece have been declining steadily during the last four
decades.
The golden jackal was extirpated from Central and Western Greece and is
currently
confined in discontinuous, isolated population clusters in the Peloponnese,
Fokida,
Samos isl., Halkidiki and north-eastern Greece. The reduction was more
pronounced
in southern Greece, which used to be the jackal’s stronghold in the sevties.
However,
important population and range expantion was observed in the past 5-10 years, a
trend
more pronounced in norteastern Greece. The minimum size of the jackal
population in
Greece was estimated during the survey at 152-170 different territorial groups.
The
largest population cluster was found in the Nestos – Vistonida area, NE Greece.
In
southern Greece, the jackal is found in the Mediterranean maquis zone at
altitudes
below 600m asl. Some individuals were observed up to 1000m asl., but were
considered exceptional. The jackal groups were located usually in areas below
300m
asl., while in the Peloponnese there were cases of jackal presence at 1000 m. In
northern Greece the species was found in areas less than 250 m., while the
highest
densities of jackal populations were found around wetlands up to 10 m asl.
Jackal
groups were found near human settlements. Competition with other canid species
seems to be quite intense. The wolf packs prevented the establishment of jackal
groups in their territories, while locations with dense jackal populations
excluded
foxes.The survey method proved effective for the detection of established jackal
groups but less so for the location of young dispersing and solitary
individuals.
Five jackals were radio tracked in Fokida – Mornos and eastern Samos in
southern Greece for 2 to 13 months. Additionally all the jackal groups in the
study
areas were intensively monitored with fixed calling stations, spotlight surveys
and
spontaneous observations. The jackals were using low altitude agro-ecosystems
with
widespread small settlements and farm houses characterized by small
cultivations and
a dense thicket vegetation mosaic. The seasonal home ranges of the 3 jackals
that
were radiotracked for more than 11 months, were significantly different between
seasons for the same animal, without any particular uniformity on seasonal
differences. Also the length between successive radiolocations were different
between
seasons but without any special pattern for the 3 study animals. Larger
succrssive
movements were observed for dispersing animals. They foraged at night at all
available habitat types but they clearly preferred open areas and often
approached
livestock pens without causing damage to livestock. They used dense
Mediterranean
scrub, reed- bramble thickets or dense tall cultivations like maize as daytime
refuges.
The availability and distribution of such thickly vegetated areas could probably
determine the number of family groups and therefore the abundance of the
jackals in
human dominated landscapes The observed home ranges were similar to the jackal
ranges found in the Ethiopian highlands and the Indian Bhal region. The
population
densities were similar with those in the arid regions of India but smaller than
those
from the Serengeti NP in Tanzania..
The dietary habits of jackals were studied in Samos, Mornos and Nestos areas
with scat analysis for frequency and biomass of consumption. The analyzed scat
samples were:
127 for Samos and Mornos and were collected during 16 months.
70 samples from adults and 95 from young jackals in Nestos in the period
between November and December.
In all the study areas the frequencies of trophic items show that the most
common food categories were mammals and birds. Even though the frequencies of
plant material and insects were high enough, their contribution to the biomass
was
low. Most of the biomass consumed by the jackals is mainly composed of domestic
mammals. The sub-adult animals in Nestos consumed also large amount of birds.
This
reveals the importance of availability of domestic animal carcasses for the
opportunistic jackals in anthropogenic Mediterranean ecosystems. The percentage
of
wild ungulate consumption was much higher in Nestos, something that was expected
from the high availability of this food source in the region. The percentage of
small
mammals in the diet of jackals in all the study areas was very low. Very few
traces of
plant material and human litter were found. The variety of the jackal diet in
Nestos
was much higher than that of other areas, because of the higher biodiversity in
this
locality. The comparison with similar studies in SE Europe and Israel clearly
shows
the dependence of the species on easily available and highly nutritional food of
anthropogenic origin. These results show very flexible and opportunistic dietary
habits which were verified in all the studies in human dominated landscapes from
India to SE Europe. The conclusions of the study support the opportunistic
nature of
the species which is capable to exploit any easily available food source mostly
of
anthropogenic origin. The availability and abundance of this type of food
supply is
greatly influencing the distribution and abundance of the species.
Keywords:
Golden jackal, Greece, Ecology, Population, Morphometry