Nüzhet Dalfes

• PhD
• Professor (Full) at Istanbul Technical University

This study estimates relative pollen productivity (RPP) for plant taxa from Southern Anatolia, an important region in the Mediterranean with a long history of human settlements. RPP estimates are required for quantitative pollen-based reconstruction of past land cover modelling. The application of the reconstruction by the REVEALS model in the Medi...

Recent climate and societal changes have increased wildfire activity and prolonged the fire season in many regions of the world. The precision of fire seasonality analysis from tree-ring records can be improved by complementing the subjectively determined intra-ring position of fire scars with more precise studies of wood formation. With this aim,...

This study considers the potential shift of biomes due to simulated changes in climatic drivers up until the end of this century, and how these changes effect the frequency of disturbances which in turn may affect the ranges of vegetation life zones. The study area is mainly the Anatolian Peninsula and its immediate surroundings, a unique location...

Biological invasions are a major component of global environmental change with severe ecological and economic consequences. Since eradicating biological invaders is costly and even futile in many cases, predicting the areas under risk to take preventive measures is crucial. Impatiens glandulifera is a very aggressive and prolific invasive species a...

Understanding how natural ecosystems are and will be responding to climate change is one of the primary goals of ecological research. Plant phenology is accepted as one of the most sensitive bioindicators of climate change due to its strong interactions with climate dynamics, and a vast number of studies from all around the world present evidence c...

The central aim of this study is to estimate the current potential distribution of Turkey’s forests and their composition in absence of anthropogenic landcover change, and in this manner to contribute to past studies on the distribution of European forest taxa by filling an important spatial gap. For our simulations, we used high resolution climate...

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 gradien...

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 imp...

Caves are semi-closed ecosystems that experience the absence of sunlight and often, poor organic matter conditions due to physical isolation. Therefore, microbial activity is a crucial factor for sustaining life in caves. However, the heterogeneity of microbial diversity and community structure in relation to different types of habitats in karstic...

Many ecological studies show that diversity of vegetation is generally sensitive to hydrometeorological variables such as temperature, precipitation, and evaporation. Furthermore, it is also known that there have been changes in the precipitation regimes due to climate change and/or land use (such as urbanization). This study investigates the tempo...

Turkey, aka Asia Minor, is situated in a distinct spot, surrounded by marine basins on three sides and an inner sea, coastlines on the northern and southern parts of the country cut off from the inner plateau by high mountain ranges showcasing different micro-climatic settings. The area, a natural corridor between two continents, also harbors a hea...

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....

In this presentation, the distributions of Oriental beech (Fagus orientalis Lipsky) under present, past (Last Glacial Maximum, LGM; 21 ka and mid-Holocene, MH; 6 ka) and future climates (Representative Concentration Pathway (RCP) 2.6, 4.5, 8.5 scenarios) were modeled using five different species distribution modeling algorithms. Output of Maxent an...

anisotropy and results

Climate change is impacting forest biomes more severely than ever, even with the ~1°C temperature warming so far. Their geographical distributions are linked to warming temperatures and decreasing precipitation. Forest species try to adapt to this change by forcing these constraints. Recent warming not only impacted the survival rates of most tree...

Eurasia has served as refugia and an intersection of important migration routes throughout the Last Glacial Maximum (LGM). Therefore, predicting the LGM climate impacts on Eurasian vegetation is crucial for an accurate representation and understanding of past migration events. Accordingly, the Quaternary vegetation of Eurasia has been studied both...

In this study, human-induced climate change over the Eastern Mediterranean–Black Sea region has been analyzed for the twenty-first century by performing regional climate model simulations forced with large-scale fields from three different global circulation models (GCMs). Climate projections have been produced with Special Report on Emissions Scen...

We developed a high quality reconstruction of May–June precipitation for the interior region of southwestern Turkey using regional tree-ring data calibrated with meteorological data from Burdur. In this study, three new climate sensitive black pine chronologies were built. In addition to new chronologies, four previously published black pine chrono...

Information about climate extremes of the future should constituted essential ingredient for any realistic impact study. This study attempts to extract such information from dynamically downscaled climate projections for Turkey and its region. Results from several AR4 global climate models (ECHAM5, CCSM and HadCM3) has been used to force at the bou...

All climate projections indicate that drastic changes are to occur in the Mediterranean Basin and Southwestern Asia. Detailed studies also foresee strong patterns of change in seasonality for most climate fields all across the country, threatening Turkey's rich biodiversity and diverse ecosystems already in trouble due to massive land use changes a...

Dendrochronological and oxygen–carbon isotopic analysis was conducted on tree rings collected at two different elevations from three different regions in western Anatolia, Turkey. Tree rings were sampled from Anatolian black pines (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) of at least 200 years old through an N–S transect covering Bolu-Me...

The outputs of three GCMs, ECHAM5, CCSM3 and HadCM3, are downscaled for the eastern Mediterranean–Black Sea region for the period 1961–1990 using a regional climate model, RegCM3, to assess the capability of these models in simulating the climatology of the region. In addition, the NCEP/NCAR Reanalysis data are also downscaled for the same period t...

In this study, we aim to examine past dry and wet events for the western Anatolia, performing local and spatial reconstructions. 17 new black pine site chronologies were developed, May–June precipitation time series were reconstructed for four localities, and the first spatial May–June precipitation reconstruction was achieved for western Anatolia....

The outputs of three GCMs, ECHAM5, CCSM3 and HADCM3, are downscaled for the eastern Mediterranean-Black Sea region for the period 1961-1990 using a regional climate model, RegCM3, to assess the capability of these models in simulating the climatology of the region. In addition, the NCEP/NCAR Reanalysis data are also downscaled for the same period t...

In this study, it is aimed to demonstrate climate change impacts on hydrometeorology of the Euphrates and Tigris Basins which are the two major water sources in the Middle East. The ICTP-RegCM3 model has been used to downscale MPI's ECHAM5/MPI-OM and NCAR's CCSM for different emission scenarios in an ongoing project supported by UNDP. The simulatio...

Temperature has been traditionally used as the primary parameter in detecting the climate change signal at scales from local to global. As being point measurements, however, temperature data come with important shortcomings such as the lack of the representivity of large areas and contamination by urban heat island effect as most stations are locat...

An overview of a newly designed parallel programming language is presented in this paper. Fortress, an outcome of the high productivity computing systems program at DARPA, is examined through its features like mathematical notation, implicitly parallel nature and ease of library coding, its potential to grow easily and its interchangeable program p...

The problem of statistical linkages between large-scale and local-scale processes is investigated through noise reduction by singular spectrum analysis (SSA) and spatial principal component analysis in order to construct appropriate statistical models for estimating the local-scale climate variables from large-scale climate processes. This paper pr...

Researchers are aware of certain types of problems that arise when modelling interconnections between general circulation and regional processes, such as prediction of regional, local-scale climate variables from large-scale processes, e.g. by means of general circulation model (GCM) outputs. The problem solution is called downscaling. In this pape...

The March 1987 blizzard over the eastern Mediterranean and Balkan regions is investigated. Northern Hemispheric and regional 250- and 850-hPa geopotential heights illustrate the formation of blocking over northern Europe and cyclogenesis over the considered area. The 850-hPa analyses and National Centers for Environmental Prediction Eta model simul...

Shows that for most reasonable assumed sedimentation rates and sediment mixing lengths the effects of bioturbation reddens the spectrum at the high frequency end with a power gain factor that has a '-2 slope' asymptotically. This implies that any climatic inference made from the high-frequency end of an ocean core variance spectrum which does not c...

A zonally averaged energy balance climate model is developed to generate zonal temperature variability through fluctuating meridional energy transports. Stochastic transport fluctuations are included in the model by multiplying the eddy diffusion coefficients by Gaussian random deviates. For a variability of eddy coefficients of 50 percent, the mod...