Search

Phelypaea tournefortii (Orobanchaceae) primarily occurs in the Caucasus (Armenia, Azerbaijan, Georgia, and N Iran) and Turkey. This perennial, holoparasitic herb is achlorophyllous and possesses one of the most intense red flowers among all plants worldwide. It occurs as a parasite on the roots of several Tanacetum (Asteraceae) species and prefers steppe and semi-arid habitats. Climate change may affect holoparasites both directly through effects on their physiology and indirectly as a consequence of its effects on their host plants and habitats. In this study, we used the ecological niche modeling approach to estimate the possible effects of climate change on P. tournefortii and to evaluate the effect of its parasitic relationships with two preferred host species on the chances of survival of this species under global warming. We used four climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) and three different simulations (CNRM, GISS-E2, INM). We modeled the species' current and future distribution using the maximum entropy method implemented in MaxEnt using seven bioclimatic variables and species occurrence records (Phelypaea tournefortii – 63 records, Tanacetum argyrophyllum – 40, Tanacetum chiliophyllum – 21). According to our analyses, P. tournefortii will likely contract its geographical range remarkably. In response to global warming, the coverage of the species' suitable niches will decrease by at least 34%, especially in central and southern Armenia, Nakhchivan in Azerbaijan, northern Iran, and NE Turkey. In the worst-case scenario, the species will go completely extinct. Additionally, the studied plant's hosts will lose at least 36% of currently suitable niches boosting the range contraction of P. tournefortii. The GISS-E2 scenario will be least damaging, while the CNRM will be most damaging to climate change for studied species. Our study shows the importance of including ecological data in niche models to obtain more reliable predictions of the future distribution of parasitic plants. [ABSTRACT FROM AUTHOR]

Climate change is significantly affecting the distribution of plants worldwide. Cyclocarya paliurus (Batal.) Iljinsk. (Juglandaceae), a rare deciduous tree, is a traditional nutraceutical tea owing to its health benefits and appealing flavor. In this study, climatic factors and soil physio-chemical factors were screened using MaxEnt modeling, and suitable habitat areas during three historical periods and under two climatic change scenarios were predicted based on 425 occurrence records. MaxEnt model performance was excellent, showing a high prediction ability, with an average area under curve value of 0.9786 ± 0.0025 and true skill statistic index of 0.9556. Eleven climatic factors, as well as four soil physio-chemical factors, were selected based on jackknife resampling. The habitat suitability simulation for three historical periods (last glacial maximum, mid-Holocene, and 1960–1990) showed that although the high-suitability area for C. paliurus decreased during the three periods, the combined intermediate- and high-suitability area increased. The analysis of the suitable habitat distributions under two global warming scenarios (RCP2.6 and RCP8.5) showed a decline in the suitable habitat area of C. paliurus in response to climatic warming. Our results provide basic references for the management of this species in nature. [ABSTRACT FROM AUTHOR]

Climate warming has resulted in rapid range shifts of plant species, but it is not well known how species with different natural distribution ranges adapt to increase in temperature through physiological adjustment. We experimentally imposed a 1.8 °C increase of air temperature to the cuttings of two common poplar species Populus yunnanensis and Populus szechuanica naturally growing in southwest China using open-top chambers. Populus yunnanensis is distributed along a narrower elevation range compared with P. szechuanica. We determined some key physiological parameters and plant growth regulator activities during the growing season without soil water limitation. Our results showed that a 1.8 °C increase in air temperature increased shoot growth of P. szechuanica through an extension of its growth period but did not affect the growth of P. yunnanensis. Malondialdehyde content, guaiacol peroxidase activities and abscisic acid content increased while indoleacetic acid content decreased in P. yunnanensis. Our results suggest that the two common poplar species in southwest China should be able to adapt to the moderate increase in temperature projected for future climate. The growth of P. szechuanica may benefit through phenological adjustment but a further increase in temperature may inhibit the growth of P. yunnanensis. For poplar plantation management, selecting species with a wide natural distribution range could provide an adaptive alternative for buffering anthropogenic induced increase in temperature and help in sustaining productivity for the long term. [ABSTRACT FROM AUTHOR]

Ascophyllum nodosum is a foundation macroalgae of the intertidal zone that distributes across latitude 41.3-69.7°N. We tested the hypothesis that growth of A. nodosum near the northern distribution edge increases with warming. We retrospectively quantified the growth of eight A. nodosum populations at West Greenland and North Norway (from 64°N to 69°N). For seven populations, we measured growth rates since 1997-2002 and for one of them we extended the time series back to 1956 using published estimates. Individuals at northern populations elongated between 2.0 and 9.1 cm year and this variability correlated with temperature and annual ice-free days. A spatial comparison of A. nodosum growth across the species distribution range showed that Northern (and coldest) populations grew at the slowest rates. Our results demonstrate that arctic climate change enhances the growth of A. nodosum populations and suggest that their productivity may increase in response to projected global warming. [ABSTRACT FROM AUTHOR]

In this study, a zonally-averaged statistical climate model (SDM) is used to investigate the impact of global warming on the distribution of the geobotanic zones over the globe. The model includes a parameterization of the biogeophysical feedback mechanism that links the state of surface to the atmosphere (a bidirectional interaction between vegetation and climate). In the control experiment (simulation of the present-day climate) the geobotanic state is well simulated by the model, so that the distribution of the geobotanic zones over the globe shows a very good agreement with the observed ones. The impact of global warming on the distribution of the geobotanic zones is investigated considering the increase of CO concentration for the B1, A2 and A1FI scenarios. The results showed that the geobotanic zones over the entire earth can be modified in future due to global warming. Expansion of subtropical desert and semi-desert zones in the Northern and Southern Hemispheres, retreat of glaciers and sea-ice, with the Arctic region being particularly affected and a reduction of the tropical rainforest and boreal forest can occur due to the increase of the greenhouse gases concentration. The effects were more pronounced in the A1FI and A2 scenarios compared with the B1 scenario. The SDM results confirm IPCC AR4 projections of future climate and are consistent with simulations of more complex GCMs, reinforcing the necessity of the mitigation of climate change associated to global warming. [ABSTRACT FROM AUTHOR]

Floristically, Taiwan is a very rich island due to her varied geography, topography and habitats. Through extended historical research involving past and present botanical inventories of the central mountains, particularly of the Hehuanshan area of Taiwan, we are now able to examine the floristic composition of four elevation zones, 2,000-2,500 m, 2,500-3,000 m, 3,000-3,500 m, and 3,500-3,950 m. We selected four study sites, namely Shinjenkan (SJK) at 2,250-2,585 m, Shihmenshan (SMS) at 3,000 m, Hehuan East Peak (HEP) at 3,401 m, and Hehuan Major Peak (HMP) at 3,408 m, and determined their α, β, and Y diversities along with their Simpson's diversity indices. Our results clearly showed that the species richness (α diversity) was significantly high and decreased as the altitude increased. Coincidently, Simpson's diversity index at 2,250 m was significantly high at 0.85, drastically decreased to 0.17 at 3,145 m, and continued to decrease to 0.10 at both sites at 3408 m. On the other hand, by comparing plant distribution data collected over a century for the Hehuanshan, Alishan and Yushan areas, we were able to predict that plants would migrate mostly from a lower to a higher elevation when the global temperature increases. For instance, in the Hehuanshan area, 16 species would move towards higher elevations and seven species would remain in their original zone. In the Alishan area, seven species would migrate and four would remain in their original zone, and in Yushan, 15 species would migrate out of their zone and five would remain. Of all of the species, at least six risk extinction, since their expected migration would take them far beyond the limits of the land available above 3,950 m. It is concluded that the alpine vegetation will be redistributed, many plant species will move towards a higher elevation and, eventually, at least six plant species (Anaphalis morrisonicola, Artemisia morrisonensis, Swertia randaiensis, Hypericum nagasawai, Angelica morrisonicola, and Cirsium arisanensis) will become extinct. [ABSTRACT FROM AUTHOR]

Climate warming is expected to cause a poleward spread of species, resulting in increased richness at mid to high latitudes and weakening the latitudinal diversity gradient. We used pollen data to test if such a change in the latitudinal diversity gradient occurred during the last major poleward shift of plant species in Europe following the end of the last glacial period. In contrast to expectations, the slope of the gradient strengthened during the Holocene. The increase in temperatures around 10 ka ago reduced diversity at mid to high latitude sites due to the gradual closure of forests. Deforestation and the introduction of agriculture during the last 5 ky had a greater impact on richness in central Europe than the earlier climate warming. These results do not support the current view that global warming alone will lead to a loss in biodiversity, and demonstrate that non-climatic human impacts on the latitudinal diversity gradient is of a greater magnitude than climate change. Climate-induced poleward shifts in plant distributions could flatten latitudinal diversity gradients. However, here the authors show that the spread of forests after the last ice age reduced diversity in central and northern Europe, and that human land-use over the past 5000 years strengthened the latitudinal gradient in plant diversity. [ABSTRACT FROM AUTHOR]