Explore the vast range of titles available.

Terrestrial ecosystems will be transformed by current anthropogenic change, but the extent of this change remains a challenge to predict. Nolan et al. looked at documented vegetational and climatic changes at almost 600 sites worldwide since the last glacial maximum 21,000 years ago. From this, they determined vegetation responses to temperature changes of 4° to 7°C. They went on to estimate the extent of ecosystem changes under current similar (albeit more rapid) scenarios of warming. Without substantial mitigation efforts, terrestrial ecosystems are at risk of major transformation in composition and structure. Science , this issue p. 920 Global vegetation change since the Last Glacial Maximum is used as an indicator of transformation under warming scenarios. Impacts of global climate change on terrestrial ecosystems are imperfectly constrained by ecosystem models and direct observations. Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity.

As many as twenty submergence events over the past 4000 years have been identified in Ukishima-ga-hara, a lowland facing the Suruga Trough in central Japan. We obtained 17 cores 5–25 m long from the reclaimed area, along with a 15 m core and two 2 m slice samples from the preserved natural marsh. The cores contain both local (Obuchi scoria, ~ 1500 BP) and regional (Kawagodaira pumice layer, ~ 3000 BP) tephra layers useful for correlating the collected cores within the study site. One core continuously records paleoenvironments from approximately 4000 BP to the present; stratigraphic observations and changes in both diatom and plant macrofossil assemblages were employed to identify 20 coastal submergence events during the period recorded in that core. We applied a Bayesian age–depth model to that core using 26 radiocarbon ages to estimate the depositional ages of submergence events (events T–A, from oldest to youngest). Two of these events (events R and H) were identified based on both stratigraphic and diatom/plan macrofossil assemblage changes, and two others were coeval with laminae and scoria layers (events J and G); the remaining events were only discernable based on changes in diatom and plant macrofossil assemblages. Across the contacts indicating submergence events, diatom assemblages showed transitions from terrestrial to planktonic species, and plant macrofossils indicated increases in floating-leaved and submerged species. Based on correlations with previous reports of historical earthquakes and geological records, events C–G are potentially linked to historical earthquakes along the Nankai Trough. If events H and R indeed represent relatively large submergence events, they might be related to the last two slip events along the Fujikawa-kako fault zone. Graphical Abstract

Today East Asia harbors many “relict” plant species whose ranges were much larger during the Paleogene-Neogene and earlier. The ecological and climatic conditions suitable for these relict species have not been identified. Here, we map the abundance and distribution patterns of relict species, showing high abundance in the humid subtropical/warm-temperate forest regions. We further use Ecological Niche Modeling to show that these patterns align with maps of climate refugia, and we predict species’ chances of persistence given the future climatic changes expected for East Asia. By 2070, potentially suitable areas with high richness of relict species will decrease, although the areas as a whole will probably expand. We identify areas in southwestern China and northern Vietnam as long-term climatically stable refugia likely to preserve ancient lineages, highlighting areas that could be prioritized for conservation of such species. East Asia contains “relict” plant species that persist under narrow climatic conditions after once having wider distributions. Here, using distribution records coupled with ecological niche models, the authors identify long-term stable refugia possessing past, current and future climatic suitability favoring ancient plant lineages.

Clarifying the influences of paleoclimate changes on the disjunct distribution formation of plants allows a historical and mechanical understanding of current vegetation and biodiversity. This study investigated the influences of paleoclimate changes on the present disjunct distribution formation of Pinus koraiensis (Korean pine) using species distribution modeling. A species distribution model (SDM) was built using maximum entropy principle algorithms (MaxEnt), data from 152 occurrences of the species, and four bioclimatic variables at 2.5 arcminute (approximately 5 km) spatial resolution. The simulation revealed the excellent fit of the MaxEnt model performance, with an area under the curve (AUC) value of 0.922 and continuous Boyce index (BCI) value of 0.925 with fivefold cross-validation. The most important climatic factor was the minimum temperature of the coldest month. Suitable habitats for the species ranged between – 30.1 and – 4.1 °C. Projected suitable habitats under the Last Glacial Maximum (approximately 22,000 years ago [ka BP]: LGM) period showed wide distributions in eastern China, the southern part of the Korean Peninsula, and the Japanese Archipelago. After the mid-Holocene (approximately 6 ka BP), the suitable habitats expanded northwards in continental regions and retreated from both north and southwest of Japan. This eventually formed disjunct suitable habitats in central Japan. An increase in temperature after the LGM period caused the migration of P. koraiensis toward new, suitable habitats in continental Northeast Asia, while species in the Japanese Archipelago retreated, forming the present disjunct distributions.

The change in ancient atmospheric CO2 concentrations provides important clues for understanding the relationship between the atmospheric CO2 concentration and global temperature. However, the lack of CO2 evolution curves estimated from a single terrestrial proxy prevents the understanding of climatic and environmental impacts due to variations in data. Thus, based on the stomatal index of fossilized Metasequoia needles, we reconstructed a history of atmospheric CO2 concentrations from middle Miocene to late Early Pleistocene when the climate changed dramatically. According to this research, atmospheric CO2 concentration was stabile around 330-350 ppmv in the middle and late Miocene, then it decreased to 278-284 ppmv during the Late Pliocene and to 277-279 ppmv during the Early Pleistocene, which was almost the same range as in preindustrial time. According to former research, this is a time when global temperature decreased sharply. Our results also indicated that from middle Miocene to Pleistocene, global CO2 level decreased by more than 50 ppmv, which may suggest that CO2 decrease and temperature decrease are coupled.

A rare coniferous Tertiary relict tree species, Thuja sutchuenensis Franch, has survived in the Daba Mountains of southwestern China. It was almost eliminated by logging during the past century. We measured size and age structures and interpreted regeneration dynamics of stands of the species in a variety of topographic contexts and community associations. Forest communities containing T. sutchuenensis were of three types: (1) the Thuja community dominated by T. sutchuenensis, growing on cliffs; (2) the Thuja-Quercus-Cyclobalanopsis community dominated by T. sutchuenensis, Quercus engleriana and Cyclobalanopsis oxyodon, along with Fagus engleriana and Carpinus fargesiana, on steep slopes; (3) the Thuja-Tsuga-Quercus community dominated by T. sutchuenensis, Tsuga chinensis, and Quercus spinosa, on crest ridges. The established seedlings/saplings were found in limestone crevices, on scarred cliff-faces, cliff-edges, fallen logs, canopy gaps and forest margins. The radial growth rate was 0.5-1.1 mm per year. Its growth forms were distorted. It had strong sprouting ability after disturbances. The T. sutchuenensis population thrives on cliffs where there is little competition from other species because of harsh conditions and rockslide disturbances. It is shade-intolerant but stress-tolerant. Its regeneration has depended on natural disturbances.

Ferns typically grow in soil that has sufficient moisture to enable the germination, fertilization and growth of gametophytes. However, the epiphytic fern, Lepisorus thunbergianus grows on tree trunks often in urban areas, where its gametophytes are susceptible to desiccation and its spores are easily washed off by rainwater. To understand how these ferns become established and survive in such challenging conditions, we conducted a quadrat survey on trunks of Prunus mume (which has cracked bark) and Ilex integra (which has smooth bark), focusing on the presence of bryophyte communities, which are known to facilitate seed establishment. Regardless of bark roughness, fern gametophytes occurred more frequently in the communities of small-leaved and short-bodied liverworts, and young fern sporophytes occurred more frequently in the communities of tall-bodied mosses. As the gametophytes of L. thunbergianus are taller than the liverworts, they are able to grow in the presence of liverworts without experiencing shading effects. However, sites with liverworts were unsuitable for fertilization of fern gametophytes because they were more desiccative environments than the sites where tall mosses grew. In habitats where tall mosses grow, fern gametophytes tended to be affected by competition from the bryophytes, whereas once fern gametophytes had established and matured, it was easy for them to generate young sporophytes because tall mosses retain sufficient moisture for the ferns' fertilization. In summary, the presence of a moss community is an important factor aiding the establishment of this epiphytic fern in desiccated urban areas.

Premise of the study: The possible persistence of wild Ginkgo biloba populations in China has long been debated but never scientifically confirmed. We test our hypothesis that the extant Ginkgo populations in the Dalou Mountains (SW China) represent fragments of the original natural Ginkgo range and offer a range of pertinent perspectives on the living fossil Ginkgo's history, prehistory, ecology, and place in human culture—all important aspects of this highly valued species. Methods: We analyzed the vegetation of the study area, determined the population age structure of Ginkgo, and compared it to existing fossil records. For supporting material, we also examined records of the lack of human presence before the mid-17th century in the area, the local people's beliefs regarding preservation of the forests and existing genetic studies. Key results: Current species composition of Ginkgo forests in the Dalou Mountains agrees closely with floristic assemblages from fossil records bearing G. biloba. Current populations are found in habitats similar to those of fossil Ginkgo, which, as today, favored rock crevices. Female to male ratios are 3:2. Estimated ages for many of the trees show that Ginkgo was present in this area prior to human settlement and indigenous peoples of this area are unlikely to have planted Ginkgo because of traditional beliefs. Our results agree with existing genetic studies that show that these mountains were glacial refugia for G. biloba. Conclusions: The corroborative evidence confirms the finding that these populations represent fragments of the original natural Ginkgo in the valley and lower mountain slopes of the Dalou Mountains.

Stratigraphic and paleontological investigations in Mugi Town, on the Pacific coast of Shikoku Island, revealed evidence of as many as five tsunami inundations from events along the Nankai Trough between 5581 and 3640 cal yr BP. Nine event deposits (E1–E9) were identified in cores ranging in length from 2 to 6 m, consisting of sandy and gravelly layers interbedded with organic-rich mud. Sedimentary structures in the event deposits observed by computed tomography included normal grading and sharp lower stratigraphic contacts. Event deposits E3, E6, E7, and E8 contained mainly brackish-marine diatom species, suggesting that they had been deposited during inundation by seawater. In addition, fossil diatom assemblages were markedly different above and below event deposits E3, E4, E6, and E8. For example, assemblages below event deposit E6 were dominated by a freshwater species (Ulnaria acus), whereas assemblages above it were predominantly brackish-marine (Diploneis smithii, Fallacia forcipata, and Fallacia tenera). We attributed these changes to the increase of marine influence due to coastal subsidence associated with subduction-zone earthquakes, as documented in the 1946 Showa-Nankai earthquakes. We conclude that event deposits E3, E6, and E8 and perhaps E4 and E7 were deposited by tsunamis generated by subduction zone earthquakes along the Nankai Trough. The ages of these event deposits, as constrained by ten radiocarbon ages, suggest that some of the tsunamis that impacted Mugi Town were correlated with those reported elsewhere along the Nankai Trough, thereby complementing the existing but still incomplete geological record for these events.

Gametophytes of epiphytic and epipetric pteridophytes occur frequently in bryophyte colonies; however, little is known about the influence of bryophytes on pteridophyte establishment. In the present study, we describe how the spore-holding capacity of bryophyte colonies contributes to the retention of pteridophyte spores in a vertical environment. Lycophytes did not grow at the sampling site; hence, we used Lycopodium spores to distinguish from any other pteridophyte spores that might have already been present in the wild. We dispersed aliquots of approximately 500,000 spores on vertically suspended bryophyte (both mosses and liverworts) colonies (5 cm × 5 cm) attached to ceramic plates. The bryophyte colonies included ten species (seven mosses and three liverworts), which have different characteristics in colony height, leaf length, and dry weight. Mudstone blocks and ceramic plates were used as control surfaces (5 cm × 5 cm). After simulated rainfall, we counted the number of spores retained in the colonies and controls. We found that the bryophyte colonies retained a significantly higher percentage of Lycopodium spores (90.7±7.4%) than the controls (ceramic plate: 7.5±20.9%; mudstone: 39.7±20.6%). The average values of retained spores within the bryophyte colonies correlated with their logarithmic values of dry weight per square centimeter (R2 = 0.62, P < 0.05). Leaf thickness and stem diameter were slightly different across species. Thus, dry weight value of bryophyte colony per unit area is very likely a simple function of number of stem-and-leaf units, which correlate closely with the surface area. Bryophyte colonies that have high surface area on which pteridophyte spores might be retained within a colony might provide a suitable environment for spore adherence in epiphytic and epipetric habitats.