scholarly journals Current status of Great Bustard Otis tarda in Turkey: population size, distribution, movements, and threats

2021 ◽  
pp. 1-13
Author(s):  
İBRAHİM KAAN ÖZGENCİL ◽  
FERDİ AKARSU ◽  
MEHMET MAHİR KARATAŞ ◽  
ARZU GÜRSOY-ERGEN ◽  
FULYA SAYGILI-YİĞİT ◽  
...  
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Breeding Population ◽  
Current Status ◽  
Great Bustard ◽  
Otis Tarda ◽  
Illegal Hunting ◽  
Irrigated Crops ◽  
Migratory Routes ◽  
Combined Data

Summary The Great Bustard Otis tarda is a globally threatened species with populations inhabiting the steppe zones of Turkey. In recent decades, its populations in Turkey have suffered severe declines in range and size. Although the remaining populations are in urgent need of protection, there has been no national-scale study on the species since 2009, and huge information gaps remain concerning its range, abundance, and movements in the country. Here, we combined data from five years of fieldwork together with all available sight and literature records to present up-to-date estimates of distribution and population size in Turkey, to better understand its movement patterns, to reveal its recent and historical population changes, and to assess its national extinction risk and threats. We find that the species’ breeding population has shrunk by 20–29% over the last five years, and there are only 559–780 breeding Great Bustards in Turkey distributed in two discrete subpopulations. Comparison with historical records shows that the species’ range has shrunk by at least 60% since the beginning of the 20th century. We suggest possible migratory routes within and through Turkey and that Turkey might have a higher regional importance for the species than previously thought. Illegal hunting, agricultural intensification, shift to irrigated crops, overgrazing, collision with powerlines, and disturbance are the most severe threats to the species in Turkey. Our national Red List assessment yields an Endangered categorisation. Further studies are needed to understand the metapopulation structure and movements of the species and to conserve its remaining populations in Turkey.

scholarly journals The Great Bustard Otis tarda population in Morocco 1998–2001

2001 ◽  
Vol 12 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Joachim Hellmich ◽  
Youssef Idaghdour
Keyword(s):  
Land Use ◽  
Habitat Loss ◽  
Carrying Capacity ◽  
Agricultural Intensification ◽  
Public Awareness ◽  
First Year ◽  
Great Bustard ◽  
Otis Tarda ◽  
Illegal Hunting ◽  
Education Campaigns

The Moroccan population of Great Bustard Otis tarda was surveyed in the four years 1998–2001. Highest numbers were counted in December 1998 (21 males, 62–65 females, four first-year males: total c. 90) and March 2001 (15 males, 60–66 females, four first-year males: total 75–81). Combining enquiry results from local people with these data, the population size for spring is estimated at 92–111 individuals, and 117–133 for winter. Reproduction is confirmed. Threats to the population include illegal hunting, habitat loss through agricultural intensification (irrigation, use of pesticides) and infrastructural changes (construction of a motorway and a powerplant), disturbance, and accidents at powerlines and antennas. Several conservation measures are suggested: cease hunting; maximize the attention given to display sites; encourage villagers to carry out “Great Bustard-friendly” land use and adapt animal stocks to the carrying capacity of their regions; clarify the situation of genetic exchange between Spanish and Moroccan populations; study movements between the Moroccan sites; monitor the size and trends of the most important subpopulations; and conduct education campaigns in schools and increase public awareness among adults.

scholarly journals Assessing the extinction risk of the great bustard Otis tarda in Africa

2016 ◽  
Vol 30 ◽  
pp. 73-82 ◽  
Author(s):  
C Palacín ◽  
B Martín ◽  
A Onrubia ◽  
JC Alonso
Keyword(s):  
Extinction Risk ◽  
Great Bustard ◽  
Otis Tarda

Great Bustard (Otis tarda)

2020 ◽  
Author(s):  
Nigel Collar ◽  
Ernest Garcia
Keyword(s):  
Great Bustard ◽  
Otis Tarda

scholarly journals Key Mortality Causes of the Great Bustard (Otis Tarda) in Central Hungary: An Analysis of Known Fatalities

2015 ◽  
Vol 22 (2) ◽  
pp. 32-41 ◽  
Author(s):  
Csaba Vadász ◽  
Miklós Lóránt
Keyword(s):  
Data Collection ◽  
Anthropogenic Factors ◽  
Relative Importance ◽  
Great Bustard ◽  
Systematic Data ◽  
Otis Tarda ◽  
Negative Effect ◽  
Breeding Attempt ◽  
Mortality Causes ◽  
Systematic Data Collection

Abstract In this study, we identified the key mortality causes of eggs, juveniles and adults of the Great Bustard (Otis tarda) and quantified the relative importance of those, based on systematic data collection that have been carried out during the period between 2005 and 2014 at the Upper-Kiskunság region in Central Hungary. Rate of mortality regarding juveniles and adults was 39.71% caused by anthropogenic factors. Within the anthropogenic factors leading to mortality, collision was represented by 81.48% of fatalities, whereas mowing/hay making represented by 18.52%. Hay making/mowing was the factor leading to unsuccessful breeding attempt with the strongest negative effect on the breeding success of the investigated population of the Great Bustard, as it was represented by 50.96% of all known mortality cases. Chemical treatment had the factor with the second strongest effect, as it was represented by 12.33% of all known mortality cases. The rate of unsuccessful breeding (hatching) caused by particular activities (hay making/mowing, tillage, harvesting) varied between 68.42% and 75.00%. It was the disturbance by passers-by which led to the highest portion of unsuccessful breeding with 83.33% unsuccessful nests.

Effects of plant availability on population size and dynamics of an insect community: diamondback moth and two of its parasitoids

2014 ◽  
Vol 104 (4) ◽  
pp. 418-431 ◽  
Author(s):  
M. Soufbaf ◽  
Y. Fathipour ◽  
J. Karimzadeh ◽  
M.P. Zalucki
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Diamondback Moth ◽  
Resource Limitation ◽  
Insect Community ◽  
Specialist Herbivore ◽  
Plant Availability ◽  
Plant Resource ◽  
Limited Variation ◽  
Density Process

AbstractTo understand the effect of plant availability/structure on the population size and dynamics of insects, a specialist herbivore in the presence of two of its parasitoids was studied in four replicated time-series experiments with high and low plant availabilities; under the latter condition, the herbivore suffered from some periods of resource limitation (starvation) and little plant-related structural refuges. Population dynamics of the parasitoid Cotesia vestalis was governed mainly by the delayed density-dependent process under both plant setups. The parasitoid, Diadegma semiclausum, under different plant availabilities and different coexistence situations (either +competitor or –competitor) showed dynamics patterns that were governed mainly by the delayed density process (significant lags at weeks 2–4). Both the competing parasitoids did not experience beneficial or costly interferences from each other in terms of their own population size when the plant resource was limited. Variation in the Plutella xylostella population under limited plant availability is higher than that under the other plant setup. For both parasitoids, under limited plant setup, the extinction risk was lower when parasitoids were engaged in competition, while under the unlimited plant setup, the mentioned risk was higher when parasitoids competed. In this situation, parasitoids suffered from two forces, competition and higher escaped hosts.

Genetic structure and population history of wintering Asian Great Bustard (Otis tarda dybowskii) in China: implications for conservation

2017 ◽  
Vol 158 (3) ◽  
pp. 761-772 ◽  
Author(s):  
Gang Liu ◽  
Xiaolong Hu ◽  
Aaron B. A. Shafer ◽  
Minghao Gong ◽  
Morigen Han ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Population History ◽  
Great Bustard ◽  
Otis Tarda ◽  
History Of

scholarly journals Density and population viability of coastal marten: a rare and geographically isolated small carnivore

2017 ◽  
Author(s):  
Mark A Linnell ◽  
Katie Moriarty ◽  
David S Green ◽  
Taal Levi
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Conservation Status ◽  
Population Viability Analysis ◽  
Credible Interval ◽  
The United States ◽  
Population Viability ◽  
Coastal Forests ◽  
Private Lands ◽  
Geographically Isolated

Pacific martens (Martes caurina) in coastal forests of Oregon and northern California in the United States are rare and geographically isolated, prompting a petition for listing under the Endangered Species Act. If listed, regulations have the potential to substantially influence land-use decisions and forestry on public and private lands, but no estimates of population size, density, and viability of remnant marten populations are available for evaluating their conservation status. We used GPS telemetry, territory mapping, and spatial mark-recapture to estimate population size and density within the current extent of Pacific martens in central Oregon, within coastal forest in the Oregon dunes national recreational area. We then estimated population viability at differing levels of human-caused mortality (e.g. roadkill). We estimated 63 adult martens (95% Credible Interval: 58-73) and 73 (range: 46-91) potential territories across two subpopulations separated by a large barrier (Umpqua River). Marten density was 1.02 per km2, the highest reported in North America. Using population viability analysis, extinction risk for a subpopulation of 30 martens ranged from 34% to 100% with two or more annual human-caused mortalities. Absent broad-scale restoration of forest to conditions which support marten populations, limiting human-caused mortalities would likely have the greatest conservation impact.

scholarly journals Underground cabling and marking of power lines: conservation measures rapidly reduced mortality of West-Pannonian Great Bustards Otis tarda

2011 ◽  
Vol 22 (3) ◽  
pp. 299-306 ◽  
Author(s):  
RAINER RAAB ◽  
CLAUDIA SCHÜTZ ◽  
PÉTER SPAKOVSZKY ◽  
EIKE JULIUS ◽  
CHRISTIAN H. SCHULZE
Keyword(s):  
Mortality Rate ◽  
Linear Models ◽  
Power Line ◽  
Distribution Range ◽  
Power Lines ◽  
Mortality Factor ◽  
Great Bustard ◽  
The West ◽  
Otis Tarda ◽  
Conservation Measures

SummaryCollisions with power lines represent an important mortality factor for Great Bustards Otis tarda throughout the distribution range of the species. This study evaluates the success of two conservation measures implemented in the West-Pannonian distribution range to reduce the number of power line collision casualties: (1) extensive underground cabling of 43.1 km power lines, and (2) marking of 89.7 km power lines starting in 2005 and 2006, respectively. The mortality rate of Great Bustards in our study area (covering 686.5 km2) decreased significantly between 2002 and 2011, predominantly caused by reduced mortality due to power line collisions. Univariate tests indicate that underground cabling and power line marking significantly decreased power line collision casualties. Generalised linear models (GLMs) highlighted the prominent effect of underground cabling. Our results indicate that five years after underground cabling and marking of power lines within core areas of the West-Pannonian distribution range of the Great Bustard, the population already benefited through a significantly decreased mortality rate. Both conservation measures most likely contributed strongly to the rapid recovery of the West-Pannonian Great Bustard population observed within the last decade.

Conservation biology of marine fishes: perceptions and caveats regarding assignment of extinction risk

2001 ◽  
Vol 58 (1) ◽  
pp. 108-121 ◽  
Author(s):  
Jeffrey A Hutchings
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Population Decline ◽  
Empirical Support ◽  
Marine Fishes ◽  
Marine Biodiversity ◽  
Population Declines ◽  
High Fecundity ◽  
Reproductive Rates ◽  
Biological Extinction

Quantitative criteria used to assign species to categories of extinction risk may seriously overestimate these risks for marine fishes. Contemporary perception is that marine fishes may be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses that marine fish are more likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more rapidly from prolonged population declines than nonmarine fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse-population recovery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats associated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine fishes to at-risk categories would be inconsistent with a precautionary approach to fisheries management and the conservation of marine biodiversity.

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