20 research outputs found
Some notes concerning the Fourier transformation of auto-correlation functions
Passage of autocorrelation function to frequency spectrum by numerical Fourier transformatio
Past, present and future distributions of Oriental beech (Fagus orientalis) under climate change projections.
Species distribution models can help predicting range shifts under climate change. The aim of this study is to investigate the late Quaternary distribution of Oriental beech (Fagus orientalis) and to project future distribution ranges under different climate change scenarios using a combined palaeobotanical, phylogeographic, and modelling approach. Five species distribution modelling algorithms under the R-package `biomod2`were applied to occurrence data of Fagus orientalis to predict distributions under present, past (Last Glacial Maximum, 21 ka, Mid-Holocene, 6 ka), and future climatic conditions with different scenarios obtained from MIROC-ESM and CCSM4 global climate models. Distribution models were compared to palaeobotanical and phylogeographic evidence. Pollen data indicate northern Turkey and the western Caucasus as refugia for Oriental beech during the Last Glacial Maximum. Although pollen records are missing, molecular data point to Last Glacial Maximum refugia in northern Iran. For the mid-Holocene, pollen data support the presence of beech in the study region. Species distribution models predicted present and Last Glacial Maximum distribution of Fagus orientalis moderately well yet underestimated mid-Holocene ranges. Future projections under various climate scenarios indicate northern Iran and the Caucasus region as major refugia for Oriental beech. Combining palaeobotanical, phylogeographic and modelling approaches is useful when making projections about distributions of plants. Palaeobotanical and molecular evidence reject some of the model projections. Nevertheless, the projected range reduction in the Caucasus region and northern Iran highlights their importance as long-term refugia, possibly related to higher humidity, stronger environmental and climatic heterogeneity and strong vertical zonation of the forest vegetation
Past, present and future distributions of Oriental beech (Fagus orientalis) under climate change projections
Species distribution models can help predicting range shifts under climate change. The aimof this study is to investigate the late Quaternary distribution of Oriental beech (Fagus orientalis)and to project future distribution ranges under different climate change scenarios usinga combined palaeobotanical, phylogeographic, and modelling approach. Five species distributionmodelling algorithms under the R-package ‘biomod2‘were applied to occurrence dataof Fagus orientalis to predict distributions under present, past (Last Glacial Maximum, 21ka, Mid-Holocene, 6 ka), and future climatic conditions with different scenarios obtainedfrom MIROC-ESM and CCSM4 global climate models. Distribution models were comparedto palaeobotanical and phylogeographic evidence. Pollen data indicate northern Turkey andthe western Caucasus as refugia for Oriental beech during the Last Glacial Maximum.Although pollen records are missing, molecular data point to Last Glacial Maximum refugiain northern Iran. For the mid-Holocene, pollen data support the presence of beech in thestudy region. Species distribution models predicted present and Last Glacial Maximum distributionof Fagus orientalis moderately well yet underestimated mid-Holocene ranges.Future projections under various climate scenarios indicate northern Iran and the Caucasusregion as major refugia for Oriental beech. Combining palaeobotanical, phylogeographicand modelling approaches is useful when making projections about distributions of plants.Palaeobotanical and molecular evidence reject some of the model projections. Nevertheless,the projected range reduction in the Caucasus region and northern Iran highlights theirimportance as long-term refugia, possibly related to higher humidity, stronger environmentaland climatic heterogeneity and strong vertical zonation of the forest vegetation
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Multi-century spatiotemporal patterns of fire history in black pine forests, Turkey
In this study, we aimed to use tree-ring based fire reconstruction to understand the spatiotemporal patterns of past fires in different climate types of western Anatolia. We collected fire scarred wood samples from living trees as wedges and remnant woods from ten sites along a transect that represents a continental to Mediterranean climate gradient. We determined fire years and assigned seasonality of fires based on the intraring position of the fire scars. We calculated fire statistics and analysed fire-climate relationships. Breakpoints in our Anatolian regional fire chronology were estimated to determine the regime shifts. A decrease in fire frequency was recorded at most of the sites after the end of the 19th and the beginning of the 20th century. We observed two critical fire regime shift periods. The period between 1853 and 1934 is characterized by highly frequent (a total of 82 fires) and simultaneous fires occurring in multiple sites and this period overlapped with the longest and most severe drought period of the past 550 years. The fire frequency decline after 1934 coincided with the period of the first forest protection law in 1937. Dry, as well as prior wet conditions were main drivers of fires in the black pine forests in western Anatolia. We observed a decrease in fire frequency in the late 19th and early 20th centuries due to fire suppression activities. Continued fire suppression activities may cause fuel accumulation and pose a risk for more intense fires and thus a paradox for forests in the future. Based on future climate projections, we will face prolonged fire seasons as a consequence of increasing drought frequency, which may shift the fire regime from surface to crown fires with the accumulation of combustible material in the understory in black pine forests.24 month embargo; available online: 20 May 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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Fire history of Pinus nigra in Western Anatolia: A first dendrochronological study
Forests in the Mediterranean basin frequently experience fires due to both anthropogenic and natural causes. There are concerns that the fire season will prolong in the Mediterranean basin, the fire frequency will increase with ongoing climate change, moreover, the fire regimes will shift from surface fires to local crown fires. Here, we aim to improve our understanding of the fire regime components of black pine forests in Turkey by 1) reconstructing a high-resolution fire chronology based on tree rings, 2) revealing the seasonality of fires, 3) investigating the relationship between fire and climate, and 4) comparing our reconstruction results with documentary data from forest management units. We collected 62 fire-scarred trees from three sites in Kütahya and developed a 368 year-long (1652–2019) composite fire chronology using dendrochronological methods. We found that at two sites major fire years coincided with dry years. Two major fire years (1853 and 1879) were common to all sites and two additional fire years (1822 and 1894) were found at two sites. Our results show a sharp decline in fire frequency after the beginning of the 20th century at all sites that can be attributed to increased fire suppression efforts and forest management activities in the 20th century. Our results suggest that the spread of fires has been actively suppressed since the first forest protection law in Turkey. Yet, tree-ring based and documentary data corroboration shows that seasonality did not change over the past +350 years. © 2021 Elsevier GmbH24 month embargo; available online 8 August 2021This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Turkey's globally important biodiversity in crisis
Turkey (Turkiye) lies at the nexus of Europe, the Middle East, Central Asia and Africa. Turkey's location, mountains, and its encirclement by three seas have resulted in high terrestrial, fresh water, and marine biodiversity. Most of Turkey's land area is covered by one of three biodiversity hotspots (Caucasus, Irano-Anatolian, and Mediterranean). Of over 9000 known native vascular plant species, one third are endemic. Turkey faces a significant challenge with regard to biodiversity and associated conservation challenges due to limited research and lack of translation into other languages of existing material. Addressing this gap is increasingly relevant as Turkey's biodiversity faces severe and growing threats, especially from government and business interests. Turkey ranks 140th out of 163 countries in biodiversity and habitat conservation. Millennia of human activities have dramatically changed the original land and sea ecosystems of Anatolia, one of the earliest loci of human civilization. Nevertheless, the greatest threats to biodiversity have occurred since 1950, particularly in the past decade. Although Turkey's total forest area increased by 5.9% since 1973, endemic-rich Mediterranean maquis, grasslands, coastal areas, wetlands, and rivers are disappearing, while overgrazing and rampant erosion degrade steppes and rangelands. The current "developmentalist obsession", particularly regarding water use, threatens to eliminate much of what remains, while forcing large-scale migration from rural areas to the cities. According to current plans, Turkey's rivers and streams will be dammed with almost 4000 dams, diversions, and hydroelectric power plants for power, irrigation, and drinking water by 2023. Unchecked urbanization, dam construction, draining of wetlands, poaching, and excessive irrigation are the most widespread threats to biodiversity. This paper aims to survey what is known about Turkey's biodiversity, to identify the areas where research is needed, and to identify and address the conservation challenges that Turkey faces today. Preserving Turkey's remaining biodiversity will necessitate immediate action, international attention, greater support for Turkey's developing conservation capacity, and the expansion of a nascent Turkish conservation ethic. (C) 2011 Published by Elsevier Ltd
Turkey's globally important biodiversity in crisis
Turkey (Türkiye) lies at the nexus of Europe, the Middle East, Central Asia and Africa. Turkey's location, mountains, and its encirclement by three seas have resulted in high terrestrial, fresh water, and marine biodiversity. Most of Turkey's land area is covered by one of three biodiversity hotspots (Caucasus, Irano-Anatolian, and Mediterranean). Of over 9000 known native vascular plant species, one third are endemic. Turkey faces a significant challenge with regard to biodiversity and associated conservation challenges due to limited research and lack of translation into other languages of existing material. Addressing this gap is increasingly relevant as Turkey's biodiversity faces severe and growing threats, especially from government and business interests. Turkey ranks 140th out of 163 countries in biodiversity and habitat conservation. Millennia of human activities have dramatically changed the original land and sea ecosystems of Anatolia, one of the earliest loci of human civilization. Nevertheless, the greatest threats to biodiversity have occurred since 1950, particularly in the past decade. Although Turkey's total forest area increased by 5.9% since 1973, endemic-rich Mediterranean maquis, grasslands, coastal areas, wetlands, and rivers are disappearing, while overgrazing and rampant erosion degrade steppes and rangelands. The current "developmentalist obsession", particularly regarding water use, threatens to eliminate much of what remains, while forcing large-scale migration from rural areas to the cities. According to current plans, Turkey's rivers and streams will be dammed with almost 4000 dams, diversions, and hydroelectric power plants for power, irrigation, and drinking water by 2023. Unchecked urbanization, dam construction, draining of wetlands, poaching, and excessive irrigation are the most widespread threats to biodiversity. This paper aims to survey what is known about Turkey's biodiversity, to identify the areas where research is needed, and to identify and address the conservation challenges that Turkey faces today. Preserving Turkey's remaining biodiversity will necessitate immediate action, international attention, greater support for Turkey's developing conservation capacity, and the expansion of a nascent Turkish conservation ethic. © 2011