Constructing climate layers is more difficult and important in mountainous areas as a result of sparse meteorological stations and complex topography. This requires a 2-stage process: quality control of meteorological data and spatial interpolation of climate data. For this article, unscreened metadata and observed data were collected from all stations in Taiwan for the period 1961-2002. A qualitycontrol procedure based on a geographic information system (GIS) allowed us to reject 13.5% of stations because of missing or erroneous metadata and filter out 8.3% of the observed data because of extreme errors or unreasonable temporal sequence and spatial patterns. After applying the quality-control procedure, the monthly mean temperature and total monthly precipitation were calculated as spatial interpolation sampling points. We evaluated the performance of 6 kriging-based spatial interpolation methods with regard to their errors by cross-validation. For interpolating the monthly mean temperature, the strong relation between temperature and elevation led us to favor modified residual kriging. For interpolating the total monthly precipitation, log-transformed kriging was chosen for practical reasons (steadier and simpler). We compared our product layers with pre-existing climate layers. The overall spatial patterns of these layers were similar, except for certain extremes in the mountains. Consequently, the GIS-based approaches presented here could help in rapid construction of adequate climate layers for regions with unconfirmed data.

Questions How do Chinese beech forests differ in species composition and environmental requirements? What are the environmental determinants for the distribution of Chinese beech forests? What is the interspecific relationship among the Fagus species and with Quercus in the communities? Location The natural range of four Chinese Fagus species, including subtropical mainland China and Taiwan Island. Methods Beech forests were sampled in 28 mountains. Community clustering and canonical correspondence analysis was applied to visualize species composition differences of the community types, and divergent environmental requirements of different Fagus species. The niche overlap among different Fagus species and with different subgroups of Quercus was measured. Based on generalized linear models, hierarchical variation partitioning was applied to estimate the contributions of climatic and topographic variables to the spatial variation in the abundance of different Fagus and Quercus species. Results (1) Among the Chinese beech forests dominated by four Fagus species, F. engleriana communities and F. hayatae communities are closer in species composition, as are the F. lucida communities and F. longipetiolata communities. (2) F. longipetiolata has the weakest and F. engleriana the strongest tolerance to freezing. The mainland F. hayatae, F. lucida and the island F. hayatae communities differ prominently along a humidity gradient from dry to wet. The spatial variation of abundance of all Fagus species is primarily related to precipitation seasonality, while the distributions of Quercus species are more sensitive to topographic feature at local scale. (3) The niche overlaps among the Fagus species are low at community level. F. engleriana and F. lucida have higher dominances in the communities than F. hayatae and F. longipetiolata. Quercus species are common components of beech forests in mainland China, but only Quercus subgenus Cyclobalanopsis species occur in F. hayatae communities in Taiwan Island. Different Fagus species have different associations with Quercus species in subgenus Quercus or Cyclobalanopsis. Conclusions The distribution of beech forests in China is primarily related to the precipitation seasonality of the monsoon climate, and differentiated on both temperature and moisture gradients. Within species ranges, the presence of oak in the beech forest is significantly regulated by topography.

Trochodendron aralioides Siebold & Zuccarini (Trochodendraceae) is a famous relic tree species. Understanding the comprehensive spatial distribution and likely impacts of climate change on T. aralioides in its main habitat—Taiwan—is of great importance. We collected occurrence data and bioclimatic data to predict the current and future (year 2050) distribution by ensemble distribution modeling on the BIOMOD2 platform. Visualization of occurrence point data revealed that the main population of T. aralioides was concentrated at medium altitudes and extended to both ends of Taiwan, being especially rich in the northern low mountains. A similar distribution pattern of occurrence probability was shown by ensemble prediction of the true skill statistic >0.8 models. Comparing the current and future distribution of T. aralioides, the overlay analysis with profile display demonstrated spatial turnover that revealed a discrepancy between different latitudes and altitudes. In the future climate, T. aralioides at the middle altitudes of central Taiwan could migrate upward, but its population in northern Taiwan could lose most of its habitat. Consequently, T. aralioides in the low mountains of northern Taiwan could be particularly in need of further conservation research, which is urgently required to mitigate climate change impacts.

Temperature lapse rate (TLR) has been widely used in the prediction of mountain climate and vegetation and in many ecological models. The aims of this paper are to explore the spatio-temporal variations and monsoon effects on the TLR in the subtropical island of Taiwan with its steep Central Mountain Region (CMR). A TLR analysis using the 32-year monthly mean air temperatures and elevations from 219 weather stations (sea level to 3852 m a.s.l.) was performed based on different geographical regions and monsoon exposures. The results revealed that the average TLR for all of Taiwan is -5.17°C km -1 , with a general tendency to be steeper in summer and shallower in winter. The results are also shallower than the typical or global average TLR of -6.5°C km -1 . During the prevailing northeast monsoon season (winter), the TLR exhibits a contrast between the windward side (steeper, -5.97°C km -1 ) and the leeward side (shallower, -4.51°C km -1 ). From the diagnosis on spatial characteristics of monthly cloud amount and vertical atmospheric profiles, this contrasting phenomenon may be explained by the warming effect of onshore stratus clouds (500 -2500 m depth) on cold and dry Siberian monsoon air on the windward side of the CMR. On the southwestern leeward side of the CMR, the low-level (1500 m), the weak ventilation atmosphere and temperature inversion make the TLR shallower than on the windward side.Key words: Temperature lapse rate, Prevailing monsoon, Spatio-temporal variation, Taiwan Citation: Chiu, C. A., P. H. Lin, and C. Y. Tsai, 2014: Spatio-temporal variation and monsoon effect on the temperature lapse rate of a subtropical island.

The beech species Fagus hayatae is an important relict tree species in subtropical China, whose biogeographical patterns may reflect floral responses to climate change in this region during the Quaternary. Previous studies have revealed phylogeography for three of the four Fagus species in China, but study on F. hayatae, the most sparsely distributed of these species, is still lacking. Here, molecular methods based on eight simple sequence repeat (SSR) loci of nuclear DNA (nDNA) and three chloroplast DNA (cpDNA) sequences were applied for analyses of genetic diversity and structure in 375 samples from 14 F. hayatae populations across its whole range. Both nDNA and cpDNA indicated a high level of genetic diversity in this species. Significant fixation indexes and departures from the Hardy–Weinberg equilibrium, with a genetic differentiation parameter of R st of 0.233, were detected in nDNA SSR loci among populations, especially those on Taiwan Island, indicating strong geographic partitioning. The populations were classified into two clusters, without a prominent signal of isolation‐by‐distance. For the 15 haplotypes detected in the cpDNA sequence fragments, there was a high genetic differentiation parameter (G st = 0.712) among populations. A high G st of 0.829 was also detected outside but not within the Sichuan Basin. Consistent with other Fagus species in China, no recent population expansion was detected from tests of neutrality and mismatch distribution analysis. Overall, genetic isolation with limited gene flow was prominent for this species and significant phylogeographic structures existed across its range except for those inside the Sichuan Basin. Our study suggested long‐term geographic isolation in F. hayatae with limited population admixture and the existence of multiple refugia in the mountainous regions of the Sichuan Basin and southeast China during the Quaternary. These results may provide useful information critical for the conservation of F. hayatae and other Chinese beech species.