Integrating Species Distribution Modelling and Spring Low-Temperature Exposure to Assess Climatic Suitability for Actinidia arguta in Europe

Actinidia arguta (kiwiberry) is a cold-hardy perennial fruit crop with increasing cultivation interest outside its native East Asian range. This study assessed its climatic suitability across Europe using an ensemble species distribution modeling (SDM) framework calibrated with occurrence records from East Asia. After occurrence filtering and spatial thinning, 1483 presence records were retained. Twenty-one candidate environmental predictors were screened for multicollinearity and four variables—temperature seasonality (BIO4), maximum temperature of the warmest month (BIO5), precipitation seasonality (BIO15) and precipitation of the warmest quarter (BIO18)—were retained in the final SDM. Five algorithms (GLM, RF, MAXNET, GAM, GBM) were evaluated using environmental cross-validation and models meeting a TSS ≥ 0.60 threshold were combined in a TSS-weighted ensemble. Temperature seasonality showed the highest permutation importance (0.491), followed by precipitation of the warmest quarter (0.316). The European projection identified comparatively high climatic suitability primarily in parts of Central and Southeastern Europe, with approximately 68,226 km2 exceeding a suitability value of 0.50 and 21,634 km2 exceeding 0.60. Environmental clamping affected 10.2% of the European projection domain but only 0.4% of the area with suitability ≥ 0.50 and none of the area with suitability ≥ 0.60. A complementary March-May analysis of climatological minimum temperature showed that spring low-temperature exposure was strongly seasonal. In March, 32.4% and 23.4% of the area with suitability ≥ 0.50 overlapped with Tmin ≤ −1.0 °C and ≤−1.5 °C scenarios respectively, whereas no corresponding overlap occurred in April or May. These temperature scenarios represent climatological exposure rather than frost-event frequency or damage probability. Overall, the results identify broad-scale patterns of climatic suitability while emphasizing that such projections should not be interpreted as direct estimates of agronomic or commercial cultivation potential.