Figure 1.
Number of Records of Mammoth Presence along the Climatic Suitability Gradient
The suitable climatic conditions were split into quartiles (Q1, red; Q2, orange; Q3, yellow; Q4, green). The suitability gradient is measured using MD scores that represent the climatic difference between each of the woolly mammoth's records (radiocarbon calibrated for 42 ky BP, 30 ky BP, and 21 ky BP periods) and the average climatic conditions for the three periods combined. Increasing MDs represent decreasing suitability of the climate.
Figure 2.
Change in the Area (%) of the Different Suitable Climatic Conditions for Woolly Mammoths
The suitability of climatic conditions based on MD was split into quartiles (Q1, red; Q2, orange; Q3, yellow; Q4, green). Q1 represents the most suitable conditions and Q4 represents the less suitable. The extent of the most suitable conditions for woolly mammoths was smaller during warmer interglacial periods, 126 ky BP and 6 ky BP.
Figure 3.
Maps of Projected Climatic Suitability for the Woolly Mammoths in the Late Pleistocene and Holocene
Suitability scores are divided into four colour-scale classes (quartiles 1 [more suitable] to 4 [less suitable] of the MD), where increasing intensities of red represent increasing suitability of the climate and increasing intensities of green represent decreasing suitability. Black points are the records of mammoth presence for each of the periods. Black lines represent the northern limit of modern humans [59]. Black dotted lines indicate uncertainty in the limit of modern humans.
Figure 4.
Estimated Number of Woolly Mammoths in Eurasia in Five Time Periods (A) and the Number of Woolly Mammoths Required To Be Killed per Person per Year (HIt) to Drive the Woolly Mammoth Population to Extinction in Their Area of Co-Existence for Four Time Periods (B–E)
(A) The red line, left y-axis, assumes a woolly mammoth population density (Dmt) of 4 individuals/km2 and the blue line of 0.1 individual/km2, right y-axis. Population density is considered to be time-independent.
(B) The plot considers a suboptimal woolly mammoth population (CR = 0.35) with a woolly mammoth density of 4 individuals/km2. (C) This plot considers suboptimal woolly mammoth population (CR = 0.35) with a woolly mammoth density of 0.1 individuals/km2. (D) This plot considers a vigorous woolly mammoth population (CR = 2.7) with a woolly mammoth density of 4 individuals/km2. (E) This plot considers vigorous woolly mammoth population (CR = 2.7) with a woolly mammoth density of 0.1 individuals/km2. Colours represent three different estimations of AMH population density [56]. Green lines: average value, red lines: maximum value, blue lines: minimum value.