Fig 1.
Overview of the Aegean coast and the location of Pergamon.
The current land cover and land use [38] are shown with three different analytical spatial boundaries of the Pergamon micro-region: the watersheds of the Bakırçay and the Madra Çay [39], the chora of Pergamon during the Roman Imperial period [30], and the walking distance that can be reached within two days (16 h) [29]. Elevation data (hillshade) is based on TanDEM-X data [40]. Sites are labeled directly at their geographic locations.
Fig 2.
Regional setting and reconstructed climatic trends for western Anatolia and the Aegean.
a) Overview of the data from the wider region around the Aegean Sea used in the current study. grid cells of the MPI-ESM 1.2 model; climatic similarity index for the present climatic situation in Bergama, based on WorldClim 2.1 data (see Section 3.3.2). Selected LegacyPollen 2.0 [57] and archaeobotanical records [58,59] are highlighted (see sections 3.2 and 3.3.4 for details). The records from Sagalassos were obtained from Düzen Tepe, and the records around Larisa were taken from Kompoloi, Krania, and Plantania. Elevation data (hillshade) is based on TanDEM-X data [40]. b) Climate variations are presented as z-scores for the period from 400 BCE to 400 CE for the northern Aegean region using a 20-year moving average of annual MPI-ESM 1.2 values. Phases of higher-than-average precipitation (z-score > 0) and lower-than-average temperature (z-scores <0) are classified as “colder and wetter”; phases of lower-than-average precipitation (z-score <0) and higher-than-average temperature (z-score >0) are classified as “warmer and drier”.
Fig 3.
Overview of the agroclimatic potential modeling framework. The model incorporates climate, topography, and soil data at a resolution of approx. 1 x 1 km. The EcoCrop parameters comprised resampled soil, topographical, and climatic inputs derived from TanDEM-X, SoilGrids, WorldClim 2.1, and the MPI-ESM 1.2 (paleo-climate model). The soil data was validated using field data from [67]. Climate anomalies are interpolated over five snapshots, with the outputs validated by pollen-based climate reconstructions derived from LegacyPollen 2.0 records [57].
Fig 4.
Comparison of pollen-based climate reconstructions and MPI-ESM 1.2 simulations.
a) Comparison between z-scores of modeled climate variables from the MPI-ESM 1.2 simulation and the pollen-based climate reconstruction between 400 BCE and 400 CE. Both models are compared using the dynamic time warping (dtw) algorithm. b) Alignment paths between both reconstructions for temperature and precipitation values.
Fig 5.
Overview of the six most conventional crops in the environs of Pergamon.
Changes in cultivation suitability over the selected five time periods (310-290 BCE, 10 BCE-10 CE, 100-120 CE, 240-260 CE, 340-360 CE), highlighting periods with different climate conditions. The hybrid model incorporates the modeled suitability of the six conventional crop types, including four cereal and two legume types. The crop-specific outputs were trimmed to prevent overrepresenting nearly unsuitable areas in the hybrid model, considering only suitability estimations >20%.
Fig 6.
Change of the areal share of different suitability classes.
Suitability classes (stacked lines) are in relation to the total area from crops combined in the hybrid model. Bar plots depict the class-specific changes in suitability between periods, showing fluctuations in cultivation suitability over time.
Table 1.
Modeled crops and their regional attestation. The listed crops are known from archaeobotanical and literary sources to have been cultivated or consumed in the Aegean region. The classification of a crop’s occurrence at a specific site, whether through trade or local cultivation, is based on the assessment by Marston and Birney (2022) [59], who followed the interpretations of the original archaeobotanical reports. Sites from the Ademnes database [58,69,70] are included, although they do not provide information on the origin of the archaeobotanical remains. For site locations, see Fig 2.
Fig 7.
Change in cultivation suitability across the seven common crops and the integrated hybrid model.
Change is expressed as a coefficient of variation across all five snapshots (Fig 5). The change in the binary hybrid model is described as the sum of changes across all snapshots.
Fig 8.
Spatial distribution of downscaled average climate variables across the five snapshots (310-290 BCE, 10 BCE-10 CE, 100-120 CE, 240-260 CE, 340-360 CE) a) average annual sum of precipitation b) average annual temperature c) coefficient of variation of the average annual sum of precipitation across the five time periods d) coefficient of variation of the average annual temperature across the five time periods.