Centaurea tchihatcheffii Fisch. & / Mey. is a critically endangered annual endemic
plant found only in Ankara. This study aimed to determine its distributional range,
metapopulation status, the effects of agricultural activities, and assess conservation
options.
Occurrences and population size estimates were carried out by ground surveys.
Two adjacent subpopulations were intensively studied during 2004-2008. Plant and
seed demographic data were collected in the field and by laboratory tests. Field
experiments simulated the effects of agricultural practices. Risks of extinction and
possible impacts of different management actions were investigated through a
population viability analysis (PVA) by constructing a two-stage stochastic model.
Six scenarios involving different management actions were run with 10,000
replications each using RAMAS Metapop.
A total of 14 patchily distributed subpopulations were found to have an extent of
occurrence of > / 700 km2. Herbicide applications caused extreme mortality and
reduced germination success, and were shown to be the major anthropogenic
threat against long-term survival of C. tchihatcheffii. Tillage led to an increase in
density and reproductive success in the following year. PVA simulations for most
scenarios predicted extinction of both subpopulations within 4 to 95 years, but a
conservation management scenario involving delayed tillage ensured viable
populations with a combined size of 21 million individuals.
PVA results demonstrated that timing and frequency of tillage is crucial. Therefore,
we propose tillage to be carried out after seed set every other year for protected
subpopulations to ensure their long term persistence. Alternatively, unprotected
subpopulations elsewhere can benefit from organic or nature-friendly farming.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12610122/index.pdf |
| Date | 01 October 2008 |
| Creators | Erguner Baytok, Yasemin |
| Contributors | Bilgin, C. Can |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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