Variations in body melanisation,ovariole number and fecundity in highland and lowland populations of Drosophila melanogaster from the Indian subcontinent

We investigated geographical variations in three fitness-related traits （body melanisation, ovariole number and fecundity） in laboratory-reared offspring of 10 populations of Drosophila melanogaster. The populations were collected from adjacent lowland and highland localities （-80-100 km apart） in the tropical as well as subtropical regions （11.15-31.06°N） covering a linear distance about 3 000 kilometers from south to north on the Indian subcontinent. Persistence of within- as well as between-population differences at 21 ℃ suggest that observed variations in fitness-related traits have a genetic basis. Populations from higher altitudes showed consistently higher trait values （1.4-fold increase） as compared with their corresponding lowland populations. By contrast, latitudinal variations were about two-fold higher across the entire continent. Along latitude as well as altitude, population means showed higher correlation values （r 〉 0.98） between all the three fitness traits. However, on the basis of within-population analysis （assorted darker and lighter flies）, changes in body melanisation were significantly correlated with fecundity but not with ovariole number. Thus, analysis of within-population trait variability should be preferred as compared with data on population means for adaptive significance of fitness-related traits. In the present study, the role of climatic selection is evident from regression analysis with changes in annual average temperature of the sites of origin of populations along latitude as well as altitude.     

Toxicological and biochemical characterizations of malathion sensitivity in two field populations of Oxya chinensis （Orthoptera： Acridoidea）

We evaluate comparative toxicity of malathion in the two populations of the grasshopper Oxya chinensis, collected from Daixian and Fanshi of Shanxi province, China. General esterases and acetylcholinesterase （ACHE） from the two populations were characterized and compared. LD50 of the Daixian population （7.58 μg/g body weight） was 2.02-fold higher than that of the Fanshi population （3.75μg/g body weight）. General esterase-specific activities in the Daixian population were 1.91,130 and 1.85-fold higher than those in the Fanshi population, when α-NA, α-NB and β-NA were used as a substrate, respectively. Kinetic studies of general esterase showed that Vmax values of general esterases hydrolyzing α-NA,α-NB and β-NA in the Daixian population were 2.15-, 1.12-, and 1.47-fold, respectively, higher than those in the Fanshi population. The AChE activity of the Fanshi population was 1.54-fold higher than that of the Daixian population. Kinetic analysis of AChE showed that significant differences were presented between the two populations in the Km values; and the Vmax value in the Fanshi population was higher than that in the Daixian population. Inhibition studies of AChE indicated that AChE from the Daixian population was 2.56-, 2.80-, and 2.29-fold less sensitive to inhibition by paraoxon, chlorpyrifos-oxon, and demeton-S-methyl, respectively, than that from the Fanshi population. These biochemical characterizations of general esterases and AChE were consistent with malathion bioassay in the two populations. It is inferred that the reduced sensitivity of altered AChE and increased general esterase activities play an important role in the differences of insusceptibility of Oxya chinensis to malathion between the two populations.     

Density Effects on Plant Height Growth and Inequality in Sunflower Populations

Comparisons between competing and non-competing sunflower （Helianthus annuus L.） populations demonstrate pronounced effects of density on plant height growth, height-to-crown width ratio, and s popuiaUon＇s height inequality. In the present study, non-destructive measurements of height and the prolected crown area of sunflower plants were taken at seven times from emergence to fruit maturation in even-aged monospeclflc stands with initial densities of 1, 4, 16, and 64 plants/m^2. The mean height of populations Increased and then decreased with increasing population density; the height Inequalities of uncrowded populations decreased during stand growth, whereas the height inequaiiUes of crowded popuisUons decreased first and then increased during stand development. The interindlvidual relationships between the relative height growth rate and height within uncrowded populations became significantly negative during population growth, whereas these relationships were negative first and then became positive during the development of crowded populations. In the uncrowded populations, the static Interindlvldual relationship between height-to-crown width ratio and volume was positive, whereas for the crowded population these relationships became negative with increasing competition for light. The data suggest that the plastic responses of plant height and height-to-crown width ratio to light competition will become more Intense with increasing competition Intensity. The results of the present study argue strongly for the Importance of size-dependent Individual-level plastic responses due to size-asymmetric light competition In generating the variations in population height inequality.     

Characteristics of soil animal community in the subalpine/alpine forests of western Sichuan during onset of freezing

Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil layer, the soil organic layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil organic layer and mineral soil layer, and this trend in soil organic layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil organic layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.     

Characteristics of soil animal community in the subalpine/alpine forests of western Sichuan during onset of freezing

Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil layer, the soil organic layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil organic layer and mineral soil layer, and this trend in soil organic layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil organic layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.     

Genetic polymorphism of mitochondrial DNA HVS-I and HVS-Ⅱ of Chinese Tu ethnic minority group

We analyzed the two hypervariable segments HVS-Ⅰ and HVS-Ⅱ of 108 Chinese Tu ethnic minority group samples for forensic and population genetics purposes.Comparing with Anderson sequence,79 polymorphic loci in HVS-Ⅰ and 40 in HVS-Ⅱ were found in Chi-nese Tu ethnic minority group mtDNA sequences,and 90 and 64 haplotypes were then defined.Haplotype diversity and the mean pair-wise differences were 0.9903±0.0013 and 5.7785 in HVS-Ⅰ,and 0.9777±0.0013 and 3.5819 in HVS-Ⅱ,respectively.By analyzing the hypervariable domain from nucleotide 1,6180 to 1,6193 in HVS-Ⅰ,we defined some new types of sequence variations.We also compared the relationship between Tu population and other populations using mtDNA HVS-Ⅰ sequences.According to Rst genetic distances,the phylogenetic tree showed that the Tu population,the Xi'an Han population,the Chinese Korean,and the Mongol ethnic group were in a clade.This indicated a close genetic relationship between them.There were far relations between the Tu population and other Chinese southern Han populations,Siberian,European,African,and other foreign populations.The results suggest that Tu population has a multi-origin and has also merged with other local populations.     

Genetic polymorphism of mitochondrial DNA HVS-I and HVS-Ⅱ of Chinese Tu ethnic minority group

We analyzed the two hypervariable segments HVS-Ⅰ and HVS-Ⅱ of 108 Chinese Tu ethnic minority group samples for forensic and population genetics purposes.Comparing with Anderson sequence,79 polymorphic loci in HVS-Ⅰ and 40 in HVS-Ⅱ were found in Chi-nese Tu ethnic minority group mtDNA sequences,and 90 and 64 haplotypes were then defined.Haplotype diversity and the mean pair-wise differences were 0.9903:±0.0013 and 5.7785 in HVS-Ⅰ,and 0.9777±0.0013 and 3.5819 in HVS-Ⅱ,respectively.By analyzing the hypervariable domain from nucleotide 1,6180 to 1,6193 in HVS-Ⅰ,we defined some new types of sequence variations.We also compared the relationship between Tu population and other populations using mtDNA HVS-Ⅰ sequences.According to Rst genetic distances,the phylogenetic tree showed that the Tu population,the Xi'an Han population,the Chinese Korean,and the Mongol ethnic group were in a clade.This indicated a close genetic relationship between them.There were far relations between the Tu population and other Chinese southern Han populations,Siberian,European,African,and other foreign populations.The results suggest that Tu population has a multi-origin and has also merged with other local populations.     

Forest characteristics and population structure of Glyptostrobus pensilis,a globally endangered relict species of southeastern China

The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained un-known up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are rela-tively healthier than those in Vietnam.     

Differences of Cu uptake and acid phosphatase activities of two Elsholtzia haichowensis Sun populations

Two Elsholtzia haichowensis Sun populations, one from Cu mine sites (Tonglushan) and the other from uncontaminated sites (Hong'an) in Hubei Province, China, were investigated in hydroponic experiments for the differences of Cu accumulation and ecophysiological responses to Cu under Cu treatment. The results showed that a significant increase in malondialdehyde (MDA) concentration in roots was observed in Hong'an population, whereas no significant change was observed in Tonglushan population. The root pressure exudates (ml) decreased significantly in Hong'an population, but increased significantly in Tonglushan population at high Cu concentration (≥ 20 μ mol/L) treatment. Cu concentration in roots of Hong'an population was significantly higher than that in Tonglushan population. For example, Cu concentration in Hong'an population was 3 times and 4 times higher than that in Tonglushan population after 20 μ mol/L Cu treatment for one day and three days, respectively. Cu concentration in Hong'an population was 20 times and 5 times higher than that in Tonglushan population after 80 μ mol/L Cu treatment for one day and three days, respectively. The intracellular and secreted acid phosphatase (APase) activities in roots were significantly higher in Tonglushan population than in Hong'an one. The intracellular APase activities in Tonglushan population were 3 times higher than those in Hong'an population after 80 μ mol/L Cu treatment for three days and five days, respectively. The root-secreted APase activities in Tonglushan population were 1.6 times and 1.8 times higher than those in Hong'an population after 80 μ mol/L Cu treatment for three days and five days, respectively. In conclusion, excessive Cu caused serious oxidative damage in roots of Hong'an population, but not in Tonglushan population. The high intracellular and root-excreted APase activities in Tonglushan population might play an important role in reducing Cu accumulation in roots and maintaining normal phosphorus physiological metabolism in root cells under Cu stress.     

Influence of tidal location on morphology, photosynthesis and pigments of the agarophyte, Gelidiella acerosa, from Northern Philippines

The red seaweed agarophyte, Gelidiella acerosa (Forssk?l) (Feldmann& Hamel) was collected from tidepools, high intertidal rocks. and shallow subtidal are as along a reef flat in Ilocos Norte, northern Philippines. The three populations were compared during the summer (dry) and rainy (wet) seasons to determine changes in morphology and photoacclimation capacity as possible use in mariculture. During summer months (February toApril) after exposure to environmental extremes (i.e. the highest percent of minus tides during daylight, high light regimes, desiccation, and solar bleaching), the populations differed in their morphologies and responses to increasing irradiance levels (P–I curve). Tidepool plants were the tallest, bushiest, and with increased diameter of cortical cells; while,high intertidal plants were the shortest, with sparse branching pattern and decreased diameter of cortical cells. Although their saturation irradiances indicated shade tolerance (Ik = 52 − 112 μmol photon m ^-2 s^-1). their differential light saturation curves (P-I curves) suggested a capacity to acclimate to ambient light regimes. For example, plants from the high intertidal zone showed higher photosynthetic rates and saturation irradiances, slightly lower initial slopes of the P-I curves and levels of light harvesting accessory pigments, rphycoerhythrin (R-PE) and rphycocyanin (R-PC), after being exposed to higher light regimes. In contrast, plants from tidepools and shallow subtidal areas had lower photosynthetic rates and saturation irradiances, slightly steeper initial slopes of the P-I curves and levels of R-PE and R-PC, having been exposed to lower light regimes. During the rainy months (June to November) no significant responses in these parameters were recorded. Comparison of the P-I responses of vegetative and tetrasporic plants showed these to vary with season. The data suggest that when plants became reproductive their physiological fitness either was unchanged or slightly enhanced. These results indicate that all three populations of G. acerosa could be used as seed stock for mariculture. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic relationships between Mt. Halla and Mongolian populations of Hipparchia autonoe (Lepidoptera: Nymphalidae)

Hipparchia autonoe belongs to the family Nymphalidae (Lepidoptera) and is designated as an endangered insect and national monument in Korea. It only inhabits a very restricted area on Mt. Halla but is widely distributed in several Asian countries including Mongolia. A previous study conducted to understand the genetic relationship between Mt. Halla and Mongolian H. autonoe for conservation purposes suffered from a limited number of samples. Therefore, we sequenced the DNA barcode region of an additional 36 H. autonoe individuals, combined them with previous data from 19 individuals, and performed phylogenetic and population genetic analyses. Furthermore, the internal transcribed spacer 2 (ITS2) region was also sequenced from the 36 samples as a nuclear DNA marker. The existence of independent haplotypes, sequence types, and significant F_ST estimates (P < 0.05) between Mt. Halla and Mongolian populations indicated hampered gene flow between the populations. Nevertheless, an absence of a reciprocal monophyletic group in Mt. Halla and Mongolian populations by cytochrome oxidase subunit I gene‐ and ITS2‐based phylogeny suggests that the genetic isolation of the Mt. Halla population from the Mongolian populations seemed not large enough to consider them independent genetic entities.     

Genetic assessment of <Emphasis Type="Italic">Abies koreana</Emphasis> (Pinaceae), the endangered Korean fir,and conservation implications

To establish a management plan for endangered and rare species, genetic assessment must first be conducted. The genetic characteristics of plant species are affected by demographic history, reproductive strategy, and distributional range as well as anthropological effects. Abies koreana E. H. Wilson (Pinaceae), Korean fir, is endemic to Korea and found only in sub-alpine areas of the southern Korean Peninsula and Jejudo Island. This species has been designated as critically endangered by the International Union for Conservation of Nature due to a continuous decline in its range and population fragmentation. We genotyped 176 individuals from seven natural populations and two afforested populations on the Korean Peninsula using 19 microsatellite loci. STRUCTURE analysis revealed two genetic clusters in natural populations (F _st  = 0.040 and R _st  = 0.040) despite low differentiation. We did not detect a significant reduction in genetic diversity or the signature of a genetic bottleneck despite population fragmentation and small population size. We deduced that this species exhibits a metapopulation structure, with the population on Jirisan Mountain acting as a source of genetic diversity for other local small populations on the Korean Peninsula, through contemporary asymmetric gene flow. However, the majority of afforested individuals on the Korean Peninsula originated from a different gene cluster. Thus, we recommend a conservation strategy that maintains two genetically unique clusters.     

Wood density as a proxy of drought-induced forest dieback in silver fir

Drought-induced dieback is a matter of global concern. It has been widely reported and could compromise the climate warming mitigation potential of forests. That is why we need reliable early-warning proxies to achieve better forecasts of forest dieback and tree death. Tree-ring data can provide some of these needed proxies. Here I propose considering minimum (MND) and maximum (MXD) wood density values as proxies of tree vulnerability against drought. This hypothesis is evaluated in silver fir (Abies alba) forests from the western Spanish Pyrenees showing ongoing dieback processes after the severe 1985 drought. MXD increased in response to warm summer conditions in 1985 whereas MND increased in response to growing-season water deficit in 1986. The average between prior MXD (MXD_t-1) and subsequent MND (MND_t) could be used to detect severe drought impacts and forecast dieback.     

Attack pattern of Platypus koryoensis (Coleoptera: Curculionidae: Platypodinae) in relation to crown dieback of Mongolian oak in Korea

The ambrosia beetle, Platypus koryoensis (Murayama), vectors the Korean oak wilt (KOW) pathogen, Raffaelea quercus-mongolicae K.H. Kim, Y.J. Choi, & H.D. Shin, in Korea, which is highly lethal to Mongolian oak, Quercus mongolica Fisch., and is considered a major threat to forest ecosystem health. We characterized the attack pattern of P. koryoensis along the lower trunk of 240 Mongolian oaks in relation to tree decline symptoms on Mt. Uam in Gyeonggi-Do Province, Korea during June-July 2009. For each tree, we recorded diameter at breast height (dbh) (DBH) and P. koryoensis entrance hole density at two heights along the lower trunk (near groundline and at 1.5 m above groundline) and on opposite sides (downslope side and upslope side). Trees were assigned to one of three dieback classes: 1) apparently healthy, no or practically no wilted foliage, and no obvious platypodine frass near the base of the tree; 2) no or only partial wilting with obvious frass near the base of the tree; and 3) apparently recently killed by KOW with all foliage wilted and mostly retained with obvious frass near the base of the tree. As dieback class increased from 1 to 3, P. koryoensis entrance hole density increased at all four trunk locations. Attack density was highest on the downslope side of the trunk near groundline, and principal component analysis indicated that this trunk location was the best indicator of tree dieback. In addition, DBH tended to increase with dieback class suggesting that larger trees were infested first.     

Assessing forest vulnerability to climate warming using a process‐based model of tree growth: bad prospects for rear‐edges

Growth models can be used to assess forest vulnerability to climate warming. If global warming amplifies water deficit in drought‐prone areas, tree populations located at the driest and southernmost distribution limits (rear‐edges) should be particularly threatened. Here, we address these statements by analyzing and projecting growth responses to climate of three major tree species (silver fir, Abies alba; Scots pine, Pinus sylvestris; and mountain pine, Pinus uncinata) in mountainous areas of NE Spain. This region is subjected to Mediterranean continental conditions, it encompasses wide climatic, topographic and environmental gradients, and, more importantly, it includes rear‐edges of the continuous distributions of these tree species. We used tree‐ring width data from a network of 110 forests in combination with the process‐based Vaganov–Shashkin‐Lite growth model and climate–growth analyses to forecast changes in tree growth during the 21st century. Climatic projections were based on four ensembles CO₂ emission scenarios. Warm and dry conditions during the growing season constrain silver fir and Scots pine growth, particularly at the species rear‐edge. By contrast, growth of high‐elevation mountain pine forests is enhanced by climate warming. The emission scenario (RCP 8.5) corresponding to the most pronounced warming (+1.4 to 4.8 °C) forecasted mean growth reductions of ?10.7% and ?16.4% in silver fir and Scots pine, respectively, after 2050. This indicates that rising temperatures could amplify drought stress and thus constrain the growth of silver fir and Scots pine rear‐edge populations growing at xeric sites. Contrastingly, mountain pine growth is expected to increase by +12.5% due to a longer and warmer growing season. The projections of growth reduction in silver fir and Scots pine portend dieback and a contraction of their species distribution areas through potential local extinctions of the most vulnerable driest rear‐edge stands. Our modeling approach provides accessible tools to evaluate forest vulnerability to warmer conditions.     

Phylogenetic structure of Brazilian savannas under different fire regimes

Questions: Fire is a strong filter in fire‐prone communities and is expected to assemble closely related species when functional traits are conserved in plant lineages. Do frequent fires assemble savannas with closely related species (phylogenetic clustering)? If so, what are the clades pruned by fire in the phylogenetic trees? Are species of semi‐deciduous seasonal forests, where fires are not frequent, less related than expected by chance (phylogenetic over‐dispersion)? Are life forms conserved in the phylogeny of the species? Location: Central and SE Brazilian savannas (Emas National Park, 18°18′S, 52°54′W; Brasília, 15°56′–15°57′S, 47°53′–47°56′W and Corumbataí‐Itirapina, 22°13′–22°15′S, 47°37′–47°39′W); and close semi‐deciduous seasonal forests (in Pirenópolis, 15°45′S, 49°04′W; Brasília, 15°33′S, 47°51′W; and São Carlos, 21°55′S, 47°48′W). Methods: We recorded woody species in savannas under different fire regimes and in semi‐deciduous seasonal forests. We obtained data from the literature and from field sampling. We compared mean phylogenetic distance of species of savanna and of nearby semi‐deciduous seasonal forest sites. We obtained significance by randomizing the species among the tips of phylogenetic trees. We also assessed whether life forms were evolutionary conserved across phylogeny of the studied plants (phylogenetic signal) with tests based on the variance of phylogenetic independent contrasts. Results: Some sites of savanna under high fire frequency were characterized by phylogenetic over‐dispersion of woody species whereas, in contrast, some sites of semi‐deciduous seasonal forest were characterized by phylogenetic clustering. We found phylogenetic signals in the traits across the phylogeny of the 801 species investigated. Conclusion: Fire may have different roles in assembling plant species in Brazilian savannas than in other fire‐prone communities. We postulate that the absence of phylogenetic clustering in the cerrado is mainly due to the persistence of long‐lived resprouting species from different plant lineages.     

Spatial and temporal variation in historic fire regimes in subalpine forests across the Colorado Front Range in Rocky Mountain National Park, Colorado, USA

Aim The historical variability of fire regimes must be understood in the context of drivers of the occurrence of fire operating at a range of spatial scales from local site conditions to broad‐scale climatic variation. In the present study we examine fire history and variations in the fire regime at multiple spatial and temporal scales for subalpine forests of Engelmann spruce–subalpine fir (Picea engelmannii, Abies lasiocarpa) and lodgepole pine (Pinus contorta) of the southern Rocky Mountains. Location The study area is the subalpine zone of spruce–fir and lodgepole pine forests in the southern sector of Rocky Mountain National Park (ROMO), Colorado, USA, which straddles the continental divide of the northern Colorado Front Range (40°20′ N and 105°40′ W). Methods We used a combination of dendroecological and Geographic Information System methods to reconstruct fire history, including fire year, severity and extent at the forest patch level, for c. 30,000 ha of subalpine forest. We aggregated fire history information at appropriate spatial scales to test for drivers of the fire regime at local, meso, and regional scales. Results The fire histories covered c. 30,000 ha of forest and were based on a total of 676 partial cross‐sections of fire‐scarred trees and 6152 tree‐core age samples. The subalpine forest fire regime of ROMO is dominated by infrequent, extensive, stand‐replacing fire events, whereas surface fires affected only 1–3% of the forested area. Main conclusions Local‐scale influences on fire regimes are reflected by differences in the relative proportions of stands of different ages between the lodgepole pine and spruce–fir forest types. Lodgepole pine stands all originated following fires in the last 400 years; in contrast, large areas of spruce–fir forests consisted of stands not affected by fire in the past 400 years. Meso‐scale influences on fire regimes are reflected by fewer but larger fires on the west vs. east side of the continental divide. These differences appear to be explained by less frequent and severe drought on the west side, and by the spread of fires from lower‐elevation mixed‐conifer montane forests on the east side. Regional‐scale climatic variation is the primary driver of infrequent, large fire events, but its effects are modulated by local‐ and meso‐scale abiotic and biotic factors. The low incidence of fire during the period of fire‐suppression policy in the twentieth century is not unique in comparison with the previous 300 years of fire history. There is no evidence that fire suppression has resulted in either the fire regime or current forest conditions being outside their historic ranges of variability during the past 400 years. Furthermore, in the context of fuel treatments to reduce fire hazard, regardless of restoration goals, the association of extremely large and severe fires with infrequent and exceptional drought calls into question the future effectiveness of tree thinning to mitigate fire hazard in the subalpine zone.     

Ecophysiological importance of cloud immersion in a relic spruce–fir forest at elevational limits, southern Appalachian Mountains, USA

Climate warming predicts changes to the frequency and height of cloud-immersion events in mountain communities. Threatened southern Appalachian spruce–fir forests have been suggested to persist because of frequent periods of cloud immersion. These relic forests exist on only seven mountaintop areas, grow only above ca. 1,500 m elevation (maximum 2,037 m), and harbor the endemic Abies fraseri. To predict future distribution, we examined the ecophysiological effects of cloud immersion on saplings of A. fraseri and Picea rubens at their upper and lower elevational limits. Leaf photosynthesis, conductance, transpiration, xylem water potentials, and general abiotic variables were measured simultaneously on individuals at the top (1,960 m) and bottom (1,510 m) of their elevation limits on numerous clear and cloud-immersed days throughout the growing season. The high elevation sites had 1.5 as many cloud-immersed days (75 % of days) as the low elevation sites (56 % of days). Cloud immersion resulted in higher photosynthesis, leaf conductance, and xylem water potentials, particularly during afternoon measurements. Leaf conductance remained higher throughout the day with corresponding increases in photosynthesis and transpiration, despite low photon flux density levels, leading to an increase in water potentials from morning to afternoon. The endemic A. fraseri had a greater response in carbon gain and water balance in response to cloud immersion. Climate models predict warmer temperatures with a decrease in the frequency of cloud immersion for this region, leading to an environment on these peaks similar to elevations where spruce–fir communities currently do not exist. Because spruce–fir communities may rely on cloud immersion for improved carbon gain and water conservation, an upslope shift is likely if cloud ceilings rise. Their ultimate survival will likely depend on the magnitude of changes in cloud regimes.     

根茎型木本克隆植物准噶尔无叶豆的种群数量动态

 根据根茎型木本克隆植物的特征, 不以种群的分株数量代表种群大小, 而尝试以不同茎级的根茎长度代表种群大小, 运用种群静态生命表、存活曲线、生殖力表和Leslie矩阵模型, 研究了准噶尔无叶豆(Eremosparton songoricum)的两个种群——A种群(46°31.09′ N, 88°33.06′ E, 紧邻乌伦古湖)和B种群(46°28.07′ N, 88°33.07′ E, 位于沙漠腹地)的种群数量动态。结果表明: 种群存活表现为Deevey-I型。A种群在中龄阶段受到的人为干扰较大, 死亡率出现高峰, 种群的净增长率(R₀)、内禀增长率(r_m)和周限增长率(λ)较低, 表现为衰退型种群, Leslie矩阵模型的模拟结果表明, 15 a内种群呈现下降趋势; B种群所受到的压力主要是干旱贫瘠的荒漠环境所导致的系统压力, 种群的R₀、r_m和λ值适中, 表现为缓慢增长型种群, Leslie矩阵模型的模拟结果表明, 15 a内种群呈现先下降、再上升的趋势。此外, 研究结果验证了Leslie矩阵模型可以扩展应用到根茎型木本克隆植物这类特殊生活型植物的种群数量动态研究上。     

Development of microsatellite markers to genetically differentiate populations of Octopus minor from Korea and China

Of the more than 300 octopus species, Octopus minor is one of the most popular and economically important species in Eastern Asia, including Korea, along with O. vulgaris, O. ocellatus, and O. aegina. We developed 19 microsatellite markers from Octopus minor and eight polymorphic markers were developed to analyze the genetic diversity and relationships among four octopus populations from Korea and three from China. The number of alleles per locus varied from 10 to 49, and allelic richness per locus ranged from 2 to 16.4 across all populations. The average allele number among the populations was 11.1, with a minimum of 8.3 and a maximum of 13.6. The mean allelic richness was 8.7 in all populations. The Hardy-Weinberg equilibrium (HWE) test revealed significant deviation in 19 of the 56 single-locus sites, and null alleles were presumed in five of eight loci. The pairwise F ( ST ) values between populations from Korea and China differed significantly in all pairwise comparisons. The genetic distances between the China and Korea samples ranged from 0.161 to 0.454. The genetic distances among the populations from Korea ranged from 0.033 to 0.090, with an average of 0.062; those among populations from China ranged from 0.191 to 0.316, with an average of 0.254. The populations from Korea and China formed clearly separated into clusters via an unweighted pair group method with arithmetic mean dendrogram. Furthermore, a population from muddy flats on the western coast of the Korean Peninsula and one from a rocky area on Jeju Island formed clearly separated subclusters. An assignment test based on the allele distribution discriminated between the Korean and Chinese origins with 96.9 % accuracy.