ARISTOTLE
UNIVERSITY OF
THESSALONIKI
Professor in Wildlife Ecology and Management
in School of Forestry and Natural Environment
visitors
Prof. Dimitrios Bakaloudis
Biodiversity loss resulting from human activities throughout the world have caused great concern in the scientific community, and the conservation of biological organisms and their habitats is one of the most promising research field in biology. Terrestrial vertebrates are one of the most challenge organisms to work with, but they threatened both in numbers and range in most of European countries the last decades. They are unique in many ways and occupy almost every possible ecological niche. However, the types and intensity of human activities altered their physical environments particularly their habitats, and in a broader scale they further influence the essential relationships within ecosystems and their associated ecological processes.
MY LATEST RESEARCH
Wildlife mortality on roads crossing a protected area: The case of Dadia-Lefkimi-Soufli National Park in north-eastern Greece
Bakaloudis et al. (2023) Journal Nat. Conservation , 74, 126443
ABSTRACT: Wildlife-vehicle collisions have been identified as an important ecological problem in most countries around the world, during the last decades. In the present work we examined the impacts on wildlife arising from two road categories crossing and adjoining the Dadia-Lefkimi-Soufli National Park (DLS NP), in north-eastern Greece. The study area is consisted of one of the most diverse fauna in Europe, with 202 bird species including 36 out of 38 European diurnal raptors, 60–65 mammal species, 29 reptiles and 13 amphibians. Vehicle collisions was the highest mortality factor in the study (83.9%) among five recorded categories, poison, electrocution, drowning, vehicle collisions and unidentified causes. 204 vehicle casualties were recorded out of 243 in total. Mammals (90.7%) were the vertebrates that mainly suffered from road mortality, including 11 species. The stone marten Martes foina contributed with the highest numbers, followed by the red fox Vulpes vulpes, the hedgehog Erinaceus roumanicus and the wild cat Felis silvestris. Although the contribution of birds on the road casualties was low, nine species were identified, including five diurnal and four nocturnal species, with raptors predominating. Most road casualties were observed in the national road network (71.6%), mainly during holidays (58.3%). Traffic volume, road category, season and blind bend were all dominant factors with different effects determining high wildlife-vehicle collision values. Mitigation measures that can reduce the harmful effects of roads on wildlife in the DLS NP are also discussed.
Population viability and conservation strategies for the Eurasian Black Vulture (Aegypius monachus) in Southeast Europe.
Dimitriou et al. (2021) Animals, 11(1), 124.
The Eurasian Black Vulture is a globally threatened raptor that in Southeast Europe only occurs in an isolated population in Greece. We examined the population viability for the species under demographic fluctuations and conservation scenarios. The current population showed no possibility of extinction for the next 100 years. However, simulated scenarios showed that the most important factor affecting the viability of the species was medium and high poisoning, leading to 94.8% and 100% probability of extinction, respectively. Furthermore, high reduction of supplementary feeding highlighted an 18.6% extinction possibility. Also, a high increase of wind farms in the area may result in 17.4% extinction possibility. Additionally, the non-establishment of the feeding station in 1987 in the study area would have resulted in an extinction risk of 7%. The species can be translocated to the Olympus National Park by releasing 80 juveniles over 10 years. The implementation of the conservation scenarios concerning the establishment of a supplementary feeding site network, and the reintroduction of the Eurasian Black Vulture in its historic range, along with the elimination of threats posed by poisoning, low food availability, and wind farms would increase the probability of the species persistence and allow the population to become a source for dispersal across Southeast Europe.
Feather stable isotopes (δ2Hf and δ13Cf) identify the Sub‑Saharan wintering grounds of turtle doves from Europe
Marx et al. (2022) European Journal of Wildlife Research, 68:21
Background: Conservation of migratory birds requires knowledge of breeding and nonbreeding ranges and the connections between them.European turtle doves (Streptopelia turtur) are Palearctic-African long-distance migrants with wintering areas in the Sub- Saharan belt that are classed as vulnerable due to strong population declines. However, detailed non-breeding locations of individuals from different migratory flyways are unknown. To identify wintering regions of turtle doves, we measured stable isotopes of feathers grown on the wintering grounds and used a dual-isotope (hydrogen (δ2Hf) and carbon (δ13Cf)) probabilistic
assignment to analyse origins of individuals migrating through the western and central/eastern flyways.
Results: The most probable wintering areas for turtle dove samples from both flyways were in the western and central Sub-Sahara. However, we found differences in δ2Hf and δ13Cf values between turtle doves following different migratory routes (western vs central/eastern flyway). This result suggests a higher likelihood of origins in the central Sub-Sahara for central and eastern migrants, while turtle doves using the western flyway originated primarily in the western Sub-Sahara, highlighting the importance of both regions for the future conservation of turtle doves from European breeding populations.
Conclusions: The establishment of migratory connectivity of populations requires sampling from birds from the European as well as Asian continent; however, we provide important results that can be used to test hypotheses regarding population declines resulting from factors experienced over
the full annual cycle for some populations.
Sibling competition affects body condition and allostatic load in the colonial nesting lesser kestrel Falco naumanni
Bakaloudis et al. (2020) Journal of Vertebrate Biology, 69(1), 19058.
Sibling competition leading to physiological stress and elevated allostatic load is driven by asymmetrical development and limited resources. To investigate these predictions, we studied broods of the lesser kestrel Falco naumanni, from a nest-box population in Armenio, Central Greece. For each nestling reared in nest-boxes, we noted the age (in days) since hatching, measured the wing chord length and body mass. We also clipped the central right rectrix for ptilochronology for subsequent analysis in the laboratory. We measured 206 nestlings from 61 broods (range 2-5 nestlings). In the case of nestlings < 18 days old (n = 198, 96.1% of all) we also measured the length of feathers. As a measure of body condition, we used the residuals of the linear regression for the relationship between wing chord length and body mass, while the growth bar width of feathers was used as a second, independent index of body size and allostatic load. A GLMM and information-theory criterion showed that both measures of body condition decreased incrementally from the first sibling to the most subordinate in the brood. Body condition of subordinate siblings was influenced by the number of siblings in the nest; i.e. the larger the brood size the greater the discrepancy in body condition between siblings. At the same time, we did not find any influence of sex on either measure of fitness. Thus, our results indirectly support the hypothesis that sibling competition may cause physiological developmental stress which is reflected in decreased body condition and increased allostatic load for younger nestlings.
Genomic evidence of demographic fluctuations and lack of genetic structure across flyways in a long distance migrant, the European turtle dove
Calderon et al. (2016) BMC Evolutionary Biology, 16: 237.
Background: Understanding how past climatic oscillations have affected organismic evolution will help predict the impact that current climate change has on living organisms. The European turtle dove, Streptopelia turtur, is a warm-temperature adapted species and a long distance migrant that uses multiple flyways to move between Europe and Africa. Despite being abundant, it is categorized as vulnerable because of a long-term demographic decline. We studied the demographic history and population genetic structure of the European turtle dove using genomic data and mitochondrial DNA sequences from individuals sampled across Europe, and performing paleoclimatic niche modelling simulations.
Results: Overall our data suggest that this species is panmictic across Europe, and is not genetically structured across flyways. We found the genetic signatures of demographic fluctuations, inferring an effective population size (Ne) expansion that occurred between the late Pleistocene and early Holocene, followed by a decrease in the Ne that started between the mid Holocene and the present. Our niche modelling analyses suggest that the variations in the Ne are coincident with recent changes in the availability of suitable habitat.
Conclusions: We argue that the European turtle dove is prone to undergo demographic fluctuations, a trait that makes it sensitive to anthropogenic impacts, especially when its numbers are decreasing. Also, considering the lack of genetic structure, we suggest all populations across Europe are equally relevant for conservation.
Organochlorine and mercury residues in eggs of the lesser kestrel (Falco naumanni) from a long term study in the eastern Mediterranean
Goutner et al. (2015) Environmental Pollution, 207, 196-204.
Organochlorine and mercury residues were analyzed in unhatched eggs of the lesser kestrel (Falco naumanni) (2002-2012) in central Greece. Concentrations graded as PDDTs > PPCBs > HCB >PHCHs > PChlordanes. Temporal declines were found in the concentrations of PDDTs, PHCHs andPChlordanes but not in Hg, HCB and PPCBs. TEQs of PCBs and their degree of metabolisation showed notime trend. The reproductive parameters showed neither a temporal trend nor a significant year effect.
No relationships occurred between the reproductive parameters per year and nest type (natural, artificial) with any of the contaminants analyzed except HCB influenced by year and clutch size. Low pollutant concentrations suggest that either lesser kestrels ranged across the year in unpolluted areas or may be caused by their short food chain. The low concentrations seem improbable to have affected the reproduction of these birds, although critical levels are still to be defined.
photo by Torsten Prohl (2005)
Breeding ecology of the Long-legged Buzzard (Buteo rufinus) in an increasing population on Cyrpus
Iezekiel, et al. (2016) J. Arid Env. 135, 12-16.
Potential indicators of the relative health of an ecological area are top predators, such as raptors. The reestablishment of a raptor population is usually considered a sign of a recovering habitat with reduced human disturbance. On Cyprus, we studied the reproductive biology of Long-legged Buzzard, Buteo rufinus, in the years 2005e2007, and collected data on population size till 2012. The clutch size for all three years was an average of 2.7 ± 0.6 eggs per breeding attempt. Nestling survival was high and of 76 chicks that hatched 68 (89.5%) fledged the nest. The overall breeding success during three years, i.e., total number of young fledged (68) from the number of eggs laid (106), of the Long-legged Buzzard population in Cyprus was 64.2%. The population strongly increased over the study period, and the information on breeding ecology of the Long-legged Buzzard are the first for this part of the Mediterranean Basin, and indicate that the population is doing well.
Factors affecting the diet of the red fox (Vulpes vulpes) in a heterogeneous
Mediterranean landscape
Bakaloudis et al. (2015) Turk. J. Zool., 39, 1151-1159.
The diet of the red fox (Vulpes vulpes) has been well studied in Europe, but limited information exists about its feeding habits in Greece and in other Mediterranean landscapes. We studied the diet variation of the red fox by analyzing contents from 219 red fox stomachs in central Greece from 2003 to 2005. We used canonical correspondence analysis (CCA) and quasi-distribution generalized linear model (GLM) response curves to investigate whether the trophic groups of the red fox diet varied temporally and/or spatially with environmental factors. Mammals, arthropods, and plants were the most important trophic groups in the diet; in particular, the European brown hare (Lepus europaeus) was consumed significantly more within hunting areas. The CCA produced a significant model for the response (trophic groups) and predictor datasets (environmental, spatial, and temporal variables). In addition, GLM response curves resulted in 13 best-fitted complexity models, which were evaluated with the Akaike information criterion. The results demonstrated 4 basic predation patterns. First, the red fox showed an opportunistic exploitation of food resources according to seasonal appearance, with temporal gradients being the main drivers affecting predation. Second, the red fox had a generalist diet, consuming cold-blooded vertebrates, arthropods, birds, and small-sized carnivores in a highly seasonal way. Third, the diet showed uniform predation on small mammals in all habitat types during the study. Finally, the red fox relies on hares within hunting areas, irrespective of habitat type or temporal gradients. Additional and long-term studies are needed to understand in depth the mechanisms involved in those observed high predation rates on hares.
