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Range-size distributions are important for understanding species richness patterns and led to the development of the controversial Rapoport’s rule and Rapoport-rescue effect. This study aimed to understand the relationship between species richness and range-size distribution in relation to environmental factors. The present study tested the following: (1) altitudinal Rapoport’s rule, and a subsequent test on climatic and ambient energy hypotheses, (2) non-directional rescue effect, and a subsequent test on effect of environmental factors associated with the distribution of narrowest to widest-range species. Altitudinal species range-size distribution increased with increasing altitude and showed a negative relationship with climatic variables. These results support the altitudinal Rapoport’s rule and climatic hypothesis; however, they do not fully support the ambient energy hypothesis. Results from testing the non-directional rescue effect showed that the inflow intensity of species from both directions (high and low elevations) affected species richness. And we found that the species with intermediate range-size, rather than narrowest or widest range-size were the main cause of a mid-peak of species richness and the non-directional rescue effect. Additionally, the richness of species with intermediate range-size was highly related to minimum temperature, habitat heterogeneity, or primary productivity. Although altitudinal range-size distribution results were similar to the phenomenon of altitudinal Rapoport’s rule, the mid-peak pattern of species richness could not be explained by the underlying mechanism of Rapoport’s-rescue effect; however, the non-directional rescue effect could explain a mid-peak pattern of species richness along altitudinal gradient. [ABSTRACT FROM AUTHOR]

The prediction of the climate change effect on plant distribution has become a primary research field for conservation practices and planning. The present research predicted future distributions of warm-adapted evergreen trees, Neolitsea sericea (Blume) Koidz. and Camellia japonica L., under climate change in the Korean Peninsula (KP) using an ensemble approach and quantified the predictive uncertainty. For these purposes, we used nine modeling algorithms and the pre-evaluation weighted ensemble method in modelling the current distributions of those evergreen trees; furthermore, we predicted their future distributions under 20 climate change scenarios and averaged the future predictions for ensemble forecasts. The results suggest that both species would expand to the northern part of KP under climate changes; however, the spatial pattern and rate of expansions would be different. C. japonica showed a faster expansion than N. sericea. While C. japonica showed both inland and northward expansions under climate change, N. sericea was mostly distributed in coastal areas. In addition, the highly suitable habitats of N. sericea and C. japonica will decline or shift to the north under climate change. This may indicate that climate change will degrade habitat suitability of those species within the distribution boundary and may restrict their continuous range expansions under further climate changes. Considering the lack of research on the climate-related range shifts of plants in Asia including KP, the present study provides fundamental and practical knowledge for a better understanding of climate-related vegetation changes in Asia as well as in KP. [ABSTRACT FROM AUTHOR]

Background: In the study, the effects of elevated CO2 and temperature on the nitrogen content, carbon content, and C:N ratio of seven rare and endangered species (Quercus gilva, Hibiscus hambo, Paliurus ramosissimus, Cicuta virosa, Bupleurum latissimum, Viola raddeana, and Iris dichotoma) were examined under control (ambient CO2 + ambient temperature) and treatment (elevated CO2 + elevated temperature) for 3 years (May 2008 and June 2011). Results: Elevated CO2 concentration and temperature result in a decline in leaf nitrogen content for three woody species in May 2009 and June 2011, while four herb species showed different responses to each other. The nitrogen content of B. latissimum and I. dichotoma decreased under treatment in either 2009 and 2011. The leaf nitrogen content of C. virosa and V. raddeana was not significantly affected by elevated CO2 and temperature in 2009, but that of C. virosa increased and that V. raddeana decreased under the treatment in 2011. In 2009, it was found that there was no difference in carbon content in the leaves of the six species except for that of P. ramosissimus. On the other hand, while there was no difference in carbon content in the leaves of Q. gilva in the control and treatment in 2011, carbon content in the leaves of the remaining six species increased due to the rise of CO2 concentration and temperature. The C:N ratio in the leaf of C. virosa grown in the treatment was lower in both 2009 and 2011 than that in the control. The C:N ratio in the leaf of V. raddeana decreased by 16.4% from the previous year, but increased by 28.9% in 2011. For the other five species, C:N ratios increased both in 2009 and 2011. In 2009 and 2011, chlorophyll contents in the leaves of Q. gilva and H. hamabo were higher in the treatment than those in the control. In the case of P. ramosissimus, the ratio was higher in the treatment than that in the control in 2009, but in 2011, the result was the opposite. Among four herb species, the chlorophyll contents in the leaves of C. virosa, V. raddeana, and I. dichotoma did not show any difference between gradients in 2009, but decreased due to the rise of CO2 concentration and temperature in 2011. Leaf nitrogen and carbon contents, C:N ratio, and chlorophyll contents in the leaves of seven rare and endangered species of plant were found to be influenced by the rise and duration of CO2 concentration and temperature, species, and interaction among those factors. Conclusions: The findings above seem to show that long-term rise of CO2 concentration, and temperature causes changes in physiological responses of rare and endangered species of plant and the responses may be species-specific. In particular, woody species seem to be more sensitive to the rise of CO2 concentration and temperature than herb species. [ABSTRACT FROM AUTHOR]

The projections of species distribution models (SDMs) have provided critical knowledge for conservation planning under climate change in the Republic of Korea. However, uncertainty about the SDM projections has been criticized as a major challenge to reliable projections. The present research investigated uncertainty among competing models (Model uncertainty) and uncertainty of future climate conditions (climate uncertainty) driving from different GCMs and CO 2 emission scenarios in predicting the future distributions of plants. For this purpose, using nine single-model algorithms and the pre-evaluation weighted ensemble method, we modeled the geographical distributions of Silver Magnolia ( Machilus thunbergii Siebold & Zucc.), a warm-adapted evergreen broadleaved tree; furthermore, we predicted its future distributions under 20 climate change scenarios (5 global circulation models (GCMs) × 4 CO 2 emission scenarios (RCPs)). The results showed a great variation in the accuracies of nine single-model projections: the mean AUC values of nine single-models ranged from 0.764 (SER) to 0.970 (RF), and the mean TSS ranged from 0.529 (SRE) to 0.852 (RF). RF (mean AUC = 0.970, mean TSS = 0.852) and the ensemble forecast (AUC = 0.968, TSS = 0.804) showed the highest predictive power, while SRE showed the lowest. The future distributions of Silver Magnolia projected with the ensemble SDM clearly varied according to GCMs and RCPs. The twenty climate scenarios produced twenty different projections of the magnolia prospective distribution. GCMs commonly projected the maximum range expansion under RCP 8.5 in 2050 and 2070, but CO 2 emission scenarios explaining the minimum expansions differed according to GCMs. In conclusion, our results show that GCMs, CO 2 emission scenarios and SDM algorithms produce considerable variations in the SDM projections. Therefore, this research suggests that understanding of model and climate uncertainties is critical for an effective conservation planning in forest management under climate change on the Korean Peninsula. [ABSTRACT FROM AUTHOR]