Abstract:

Aims Prediction of potential distribution of tree species and their responses to climate change is an increasingly important field of global change. Larix are important tree species in northeastern China. In this study we predict the potential distribution of three Larix species based on “climatic-topographic" relationships. Our aims are to determine: 1) the dominant factors that control the distributions of the three Larix species and 2) the sensitivities of the species to climate change.

Methods Spatial overlap analysis was used to sample the distribution information of the three Larix species and corresponding environmental factors. A logistic regression model was used to explore the quantitative relationships between environmental factors and Larix species. A map calculator method was used to transform the results of the logistic regression model to a prediction map in ArcGIS. Three indices (sensitivity, specificity and percentage of correctness) were used to assess the prediction accuracy of the logistic regression models. Five temperature change scenarios (+1 ℃, +2 ℃, +3 ℃, +4 ℃, and +5 ℃) and six precipitation change scenarios (-30%, -20%, -10%, +10%, +20%, and +30%) were used to explore the impacts of climate change on the distributions of the three Larix and the sensitivities of the species to climate factors.

Important findings Mean annual temperature, annual precipitation and elevation were found to be dominant factors controlling the distributions of the Larix species. The sensitivity of the species changed from 61% to 88%, the specificity changed from 80% to 99.8% and the percentage of correctness changed from 80% to 99.8%. Larix gmelinii decreases by 12% and L. olgensis var. changpaiensis and L. principis-rupprechtii increase by 23% and 500%, respectively, with the temperature increase 1 ℃. L. olgensis var. changpaiensis increases by 64% and L. gmelinii and L. principis-rupprecntii decrease by 12.5% and 15%, respectively, with the precipitation increasing 10%. With climate change to “warm and dry" (+5 ℃, -30%), L. gmelinii shifts northwestward by about 100 km, L. olgensis var. changpaiensis expands northwestward by about 100 km and L. principis-rupprecntii expands northeastward by about 800 km. With climate change to “warm and wet" (+5 ℃, +30%), L. gmelinii shifts northwestward by about 400 km, L. olgensis var. changpaiensis expands northwestward by about 550 km and L. principis-rupprecntii expands northeastward by about 320 km. All three species are sensitive to climate change; therefore, future climate change in northeastern China may greatly impact their distributions.

Key words: Larix gmelinii, Larix olgensis var. changpaiensis, Larix principis-rupprecntii, potential distribution, climate change, sensitivity