Cold Temperate Regions Research Articles

Contribution of nitrogen sources to streams in mixed-use catchments varies seasonally in a cold temperate region

Intensive agriculture and growing human populations are important nitrogen (N) sources thought to be associated with eutrophication. However, the contribution and seasonality of N delivery to streams from human activities is poorly understood and knowledge of the role of stream communities in the assimilation of N from human activities is limited. We used N and oxygen stable isotope ratios of dissolved inorganic N (DIN) and concentrations of artificial sweeteners to identify the relative contribution of key sources of anthropogenic N (i.e., fertilizers, human, and livestock waste) to tributaries of the Red River Valley (RRV), Manitoba, Canada. Water and algae were sampled in 14 RRV tributaries during snowmelt, spring, summer, and autumn; and water was sampled at three locations in the Red River in spring, summer, and autumn. δ15N values of DIN in tributary water differed seasonally and were greatest during snowmelt. Incorporation of ammonium δ15N provided evidence for the importance of manure N to tributaries during snowmelt. Fertilizer and municipal lagoons served as principal sources of N to streams in spring and summer. Human and livestock waste sources of N were the dominant contributor to algae at greater than 90% of sites and algae δ15N was greatest at sites downstream of municipal lagoons. We also showed that the tributaries contribute human and livestock waste N to the Red River, though much of the nitrate in the river originates outside of Manitoba. Overall, our study determined that the anthropogenic sources of N to RRV streams vary seasonally, likely due to regional hydrologic conditions. Our study also showed the potential of artificial sweeteners and ammonium δ15N as tools for identifying N sources to rivers. Moreover, we demonstrate the need for the management of N sources and the protection of stream function to control downstream transfer of N from landscapes to waterbodies.

Biophysical controls on nitrous oxide emissions following rain-induced thawing of frozen soil microcosms by simulated rainfall

In cold temperate humid regions, peak nitrous oxide (N2O) fluxes coincide with spring snowmelt. However, other extreme climatic events in the non-growing season, such as rainfall that causes temporary thawing at the bare soil surface without snow cover, could be responsible for appreciable fluxes of N2O. The objective of this study was to quantify the proportion of ice-trapped N2O and biologically-produced N2O released following a rain-induced thawing event on soils collected in late fall. The lab experiment was done in soil-filled microcosms after the soil surface was frozen at −20 °C for 2 h, which generated a 1–2 cm ice layer at the soil surface, before they were injected with N2, N2O and 15N2O gas at 5 cm depth and then received different amounts of water with customized rainfall simulators (0, 3, 7.5 or 15 mm simulated rainfall h−1) at 4 °C. Gas samples were collected at 2, 6, 12, 24, 48 and 96 h after gas injection. Soil temperature and water content increased faster after rain-induced thawing than after the air-induced thawing event. The release of ice-trapped N2O was not affected by rain-induced thawing because soil pores filled with melted ice-water, which slowed N2O diffusion and reduced N2O to nitrogen gas (N2), based on the production of 15N–N2. However, high simulated rainfall intensity (7.5 and 15 mm h−1) contributed to greater biological N2O emission after 48 h. We conclude that rainfall on a frozen bare soil surface in cold temperate humid regions may cause N loss through harmless N2, rather than the greenhouse gas N2O.

Soil nutrient availability and microclimate are influenced more by genotype than by planting stock type in hybrid poplar bioenergy buffers on farmland

Bioenergy buffers planted with fast-growing woody crops such as hybrid poplars (Populus spp.) are increasingly integrated into agricultural land to enhance the provision of ecosystem services. Genotype and planting stock type selection may influence buffer establishment success and soil properties, which may affect buffer functions such as soil nutrient removal, hydrological regulation (i.e. soil dewatering) or local climate regulation (i.e. temperature reduction). This farm-scale study tested the effects of two unrelated hybrid poplar genotypes (P. deltoides × P. nigra, genotype D × N-3570 and P. maximowiczii × P. balsamifera, genotype M × B-915311) and two planting stock types (unrooted whips and bare-root stocks) on biomass growth, soil nutrient availability and soil microclimate in 15 m wide bioenergy buffers located downslope of hayfields in the cold temperate region of southern Québec, Canada. Poplar genotype had an important effect on biomass growth, soil microclimate and the supply rates of several macronutrients and micronutrients, while planting stock type had little effect on these variables. The P. maximowiczii × P. balsamifera genotype produced the highest biomass and had generally lower nutrient availability in the soil, but not for soil NO3, which was less available under the P. deltoides × P. nigra genotype. Compared to the hayfield soils, only the P. maximowiczii × P. balsamifera genotype maintained a lower supply rate of available P in the buffer soil. Compared to the hayfield soils, NH4 supply rates were lower in the buffers for both genotypes, while NO3 supply rates were similar or higher. Both genotypes had the capacity to maintain cooler soil temperatures and lower moisture content in the soil of the buffer compared to the adjacent hayfields, but this capacity was greater for the P. maximowiczii × P. balsamifera genotype. Because plant-soil interactions are strongly affected by hybrid poplar genetics, genotype selection is an important consideration in the design of multifunctional agricultural buffers. In temperate agroecosystems, future studies should try to identify productive poplar genotypes that would decrease topsoil NO3 and P availability and reduce soil water content in order to minimize potential N and P losses from buffer soils during runoff events.

Designing naturally-conditioned dwellings for warm and cold-temperate regions of Chile

The central problem addressed by this paper is the fuel poverty experienced in Chile as a result of poor thermal performance of dwellings, a problem commonly encountered throughout the country, even in new housing. The domestic consumption of fuels used for thermal regulation of dwellings accounts for a large proportion of national energy use, gas emissions, and household expenditures. This study aims to alleviate these issues by presenting building designs that can provide comfortable indoor thermal conditions without a need for conventional energy fuels. Following the findings of field studies, the design of standard dwellings has been optimized using computational studies that were conducted with consideration for the country’s main climatic regions. The results of this study have shown that the application of passive design measures can be sufficient for achieving thermal comfort conditions, thereby reducing the use of domestic fuels to near-zero levels in most of the country.

Molecular basis of triterpene-based chemophenetics in ferns

A hypothesis that squalene cyclase genes are widely distributed throughout ferns was proposed. We successfully isolated a squalene cyclase pseudogene from a fern from which no triterpene hydrocarbons were detected Ferns are the most primitive vascular plants, with their locations ranging from tropical to cold temperate regions and from lowland to alpine zones. The triterpene hydrocarbons and their derivatives are characteristic fern metabolites, and are also chemophenetic markers. Recently, our biosynthetic study into fern squalene cyclases (SCs), the enzymes responsible for triterpene synthesis, gave an unexpected inconsistency between genotype (enzyme function) and chemotype (triterpene profile). This finding prompted us to propose a hypothesis that SC genes are widely distributed throughout ferns and lycophytes whether or not they produce triterpene hydrocarbons. To test this hypothesis, we employed a multifaceted approach based on phytochemical, biochemical, and phylogenetic analyses. As anticipated, we successfully isolated two SC pseudogenes from a fern from in which no or only one triterpene hydrocarbon was detected. Subsequent mutagenesis experiments resulted in the functional conversion of these pseudogenes into active SC genes. Given an auxiliary hypothesis regarding the inherent limit of the degenerate polymerase chain reaction (PCR) method, the overall dataset supported our hypothesis, although correction was required with respect to plant coverage. Not only did the corrected hypothesis outline the distribution of SC genes throughout ferns, it provided insight into the molecular basis of the triterpene-based chemophenetics in ferns, which is also discussed.

Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

ABSTRACT After the rice harvest in Japan, rice straw (RS) is usually cut by combine harvester and incorporated into the soil to improve its fertility. In mixed crop–livestock systems, however, RS is collected and used as livestock feed, and cow dung compost (CDC) is then applied to the soil. This system utilizes the residual organic matter from both rice production and livestock husbandry to make each product. CDC application is also considered to improve the fertility of paddy soil. However, the nutrient input from CDC and the effect of CDC application on soil fertility vary among regions and/or soil types. We compared soil fertility between RS application (RS treatment, avg. 32 years) and RS removal plus CDC application (CDC treatment, avg. 21 years) in 79 paddy fields in Mamurogawa town, Yamagata Prefecture, a cold temperate region of Japan, and measured the nutrient contents in the applied RS and CDC. The total C content of RS was significantly higher than that of CDC, whereas the N, P, K, and Si contents of CDC were significantly higher than those of RS. However, there was no significant difference in paddy soil fertility – as measured by soil organic C, total N, CEC, available N, P, and Si, exchangeable K, Ca, and Mg, base saturation percentage, pH, and bulk density – between the treatments. The soil fertility of most fields was adequate by RS or CDC treatment. Thus, leaving RS in paddy fields or removing it and then adding CDC to the paddy fields has a similar effect in maintaining adequate soil fertility for single rice production or rice–livestock production systems.

Inventory and Historical Changes in the Marine Flora of Tomioka Peninsula (Amakusa Island), Japan

Intensive algal sampling was conducted from 2012 to 2017 in the Tomioka Peninsula, Amakusa-Shimoshima Island (the East China Sea, Japan), yielding a total of 293 benthic macroalgal taxa, of which 63% were red algae, 16% were brown algae, and 19% were green algae. The majority (69%) of species were previously recorded only for the tropics and/or subtropics, whereas 31% of species were recorded for temperate latitudes. Among all species of algae found from 2012 to 2017 in the Tomioka Peninsula, 163 species (56%) were newly identified species for Amakusa-Shimoshima Island, including six taxa, which were recorded in Japan for the first time. Comparison of the current data from the Amakusa-Shimoshima Island with those of nearby tropical regions suggested that the recent marine flora of the Amakusa-Shimoshima Island was more closely affiliated with the flora of a warm-temperate region. Moreover, we found that the benthic flora of the Tomioka Peninsula was significantly changed between the 1950s (Segawa & Yoshida 1961) and 2012–2017. For example, the species diversity was increased by two times, mainly at the expense of red and green algae, and the biogeographic status of the benthic flora was changed from the flora of a cold-temperate region to the flora of a warm-temperate region, which could be attributed to an introduction of red algae from the tropics of South East Asia and widespread opportunistic green algae, as well as the disappearance of cold-water brown algae. Collectively, our data suggested that these changes were driven by the global warming effect on the ocean.

Macropredators as shapers of invaded fouling communities in a cold temperate port

Ports are vulnerable to biological invasions because of the high shipping exchange and the abundance and diversity of artificial structures. These artificial environments provide new habitats for fouling communities, commonly hosting a large number of exotic species. The colonization of artificial structures is influenced by large and small scale processes, such as differences in recruitment time (that may vary with season and availability of new substrates) or predation. In cold temperate regions, with a marked seasonality, not only the starting time of colonization may influence fouling community structure but also the community of macropredators associated. This study addressed the following question: What is the effect of macropredators on invaded fouling communities started at different time in a cold temperate port? To asses this, the following experimental treatments were assigned to three plates attached to a fiberglass structure: exclusion, open cage and open plate. At the beginning of each season, seven of these structures were tied to port pilings, each one containing the three experimental treatments. We found that fouling communities are shaped by macropredators, such as sea urchins, gastropods and crabs, and that their effect on community structure depends on the time or season in which the colonization started. Exotic ascidians were absent in open plates and open cages when macropredators were present, and species diversity was highest when these predators were excluded. Our results suggest that predation at high latitudes in cold temperate regions might be more important than what is predicted in recent works. Although our study is conclusive on specific points, it also exposes a need for further research disentangling the processes regulating the colonization of artificial fixed versus floating structures at different latitudes.

The invasive tree staghorn sumac affects soil N2 -fixing bacterial communities in north China.

Soil N2 -fixing bacterial communities (SNB) can enhance soil N availability and the invasiveness of invaders. Some invaders display different degrees of invasion across different climate regions. Given that bacterial communities may change with different climate regions, it is important to understand soil micro-ecological mechanisms driving the successful invasion of invaders across different climate regions. This study performed cross-site comparisons to comprehensively analyse effects of the invasive tree staghorn sumac (Rhus typhina L.) on the structure of SNB. In north China, we selected three sites within two sampling regions (a warm temperate region and a cold temperate region). Staghorn sumac invasion did not significantly affect soil physicochemical properties and the diversity and richness of SNB. LEfSe analysis showed that numerous SNB taxa changed significantly during staghorn sumac invasion. This may be attributed in part to the selective effects of allelochemicals released by staghorn sumac via leaf litter and/or root exudates. Consequently, staghorn sumac invasion may alter the structure, rather than the diversity and richness, of SNB to facilitate its invasion process by establishing a favourable soil microenvironment in the invaded habitats. The number of species and richness of SNB under staghorn sumac invasion were significantly lower in the warm temperate region than in the cold temperate region. A possible reason for the increased diversity and richness of SNB under staghorn sumac invasion in the cold temperate region may be because staghorn sumac in the cold temperate region can provide more nutrients into the soil sub-ecosystem, presumably to support a higher diversity and richness of SNB via the nutritional requirements of SNB. The changed structure of SNB under staghorn sumac invasion, especially across different climate regions, may play an important role in its successful invasion across most regions of north China.

Evolution of Cold Acclimation and Its Role in Niche Transition in the Temperate Grass Subfamily Pooideae.

The grass subfamily Pooideae dominates the grass floras in cold temperate regions and has evolved complex physiological adaptations to cope with extreme environmental conditions like frost, winter, and seasonality. One such adaptation is cold acclimation, wherein plants increase their frost tolerance in response to gradually falling temperatures and shorter days in the autumn. However, understanding how complex traits like cold acclimation evolve remains a major challenge in evolutionary biology. Here, we investigated the evolution of cold acclimation in Pooideae and found that a phylogenetically diverse set of Pooideae species displayed cold acclimation capacity. However, comparing differential gene expression after cold treatment in transcriptomes of five phylogenetically diverse species revealed widespread species-specific responses of genes with conserved sequences. Furthermore, we studied the correlation between gene family size and number of cold-responsive genes as well as between selection pressure on coding sequences of genes and their cold responsiveness. We saw evidence of protein-coding and regulatory sequence evolution as well as the origin of novel genes and functions contributing toward evolution of a cold response in Pooideae. Our results reflect that selection pressure resulting from global cooling must have acted on already diverged lineages. Nevertheless, conservation of cold-induced gene expression of certain genes indicates that the Pooideae ancestor may have possessed some molecular machinery to mitigate cold stress. Evolution of adaptations to seasonally cold climates is regarded as particularly difficult. How Pooideae evolved to transition from tropical to temperate biomes sheds light on how complex traits evolve in the light of climate changes.

Study on the physiological indices of Pinus sibirica and Pinus koraiensis seedlings under cold stress

Although Pinus sibirica and Pinus koraiensis are resistant to cold or low temperatures in the cold temperate regions of the northern hemisphere, the former has a stronger cold resistance. Research has been limited to the comparison of physiological responses of the two species to cold stress. In this study, 5-year-old seedlings of P. sibirica and P. koraiensis were subjected to six temperature treatments, [20 °C (control), 0 °C, − 20 °C, − 40 °C, − 60 °C, and − 80 °C], under different stress periods (6, 12, 24, and 48 h). The results showed that differences in each physiological index were significant between P. sibirica and P. koraiensis, except for the permeability of cell membranes, reactive oxygen species, proline and soluble proteins. An ANOVA test indicated that there were extreme differences among the temperatures for each index, stress time and temperature × time for most indices. All indices showed a similar trend for P. sibirica and P. koraiensis with decreasing temperature or the extension of stress time. Soluble sugars and proline increased at 0 to − 20 °C and then remained unchanged with temperature decline. Other indices showed an increase from 20 to − 20 °C, stable from − 20 to − 40 °C and a decrease from − 40 to − 80 °C. All the indices increased and then declined along with the prolonged cold stress time, except for the control. From 0 to − 40 °C, the permeability of cell membranes, relative conductivity, reactive oxygen species and malonaldehyde of P. koraiensis seedlings were higher than in P. sibirica, but superoxide dismutase, peroxidase, catalase activity and soluble sugars, proline, and soluble proteins content emerged as opposite. This study compared the physiological mechanism responses to cold stress between P. sibirica and P. koraiensis to provide the basis for the introduction, distribution, and genetic improvement of these coniferous species.

Variation in cranial morphology of bottlenose dolphins (genus Tursiops) off South Africa

AbstractTaxonomy plays an important role in conservation biology. Despite the variety of methods used to differentiate units, some groups, such as Delphinidae within the Cetacea have proven difficult to untangle. This study aimed to shed light on morphological variation of the genus Tursiops in South African waters using geometric morphometrics and to distinguish morphological groups and variation in these groups. A total of 241 crania of Tursiops spp. were analyzed using a suite of 2‐dimensional landmarks defined on photographs of the specimens. Results revealed two distinct morphological groups, with the smaller cluster comprised mainly of specimens from the cold temperate region off the west coast and the larger cluster comprised of specimens mainly from the warm temperate and subtropical regions off the south and east coast, respectively. We suggest that these groups correspond to different species of Tursiops, but this result requires further support. These groups were treated as separate entities and sexual dimorphism and geographic variation were assessed within each group. While sexual dimorphism and geographic variation were not significant within Cluster D1 and V1, they were significant within Clusters D2 and V2. The few Cluster 1 specimens found in the warm temperate and subtropical regions, relative to the number of Cluster 2 specimens, could be an indication of an offshore distribution for this group in these regions. Alternatively, the smaller cluster may also be indicative of a potentially small population size.

Distribution and Driving Factors of Forest Swamp Conversions in a Cold Temperate Region.

Forest swamps are widely distributed in cold temperate regions, with important landscape and ecological functions. They are prone to conversion caused by complex factors. Forest swamp conversions involve forest swamping, meadow swamping, water body swamping, and conversion to farmland. An understanding of the landscape characteristics and primary environmental factors driving forest swamp conversions is imperative for exploring the mechanism of forest swamp conversions. We investigated the landscape characteristics of forest swamp conversions and quantified the relative importance of environmental factors driving these conversions for the period from 1990 to 2015 in the Great Xing’an Mountains of China. We found that forest swamping displayed high patch numbers (34,916) and density (8.51/100 ha), commonly occurring at the edge of large areas of forests. Meadow swamping was localized with low patch numbers (3613) and density (0.88/100 ha) due to lack of water recharge from ground water. Water body swamping had complex shapes (perimeter area ratio mean = 348.32) because of water table fluctuations and helophyte growth during this conversion process. Conversions to farmland presented fairly regular (perimeter area ratio mean = 289.91) and aggregated (aggregation index = 67.82) characteristics affected by agricultural irrigation and management. We found that climatic and geomorphic factors were relatively important compared to topographic factors for forest swamp conversions. Negative geomorphic conditions provided the waterlogging environment as a precondition of swamp formation. Sufficient precipitation was an important source of water recharge due to the existence of permafrost regions and long-term low temperature reduced the evaporation of swamps water and the decomposition rate of organisms. These wet and cold climatic conditions promoted forest swamp development in cold temperate regions. Humans exerted a relatively important role in forest swamping and conversions to farmland. Fire disturbance and logging accelerated the conversion from forest to swamp. This study provides scientific information necessary for the management and conservation of forest swamp resources in cold temperate regions.

Impact of projected climate change on workability, attainable yield, profitability and farm mechanization in Norwegian spring cereals

In cold-temperate climate with high soil water content in spring, the farmer often faces the choice between topsoil compaction during seedbed preparation and delayed sowing, both of which may reduce attainable cereal yield. The objective of this study was to explore whether future climate change with increasing precipitation would aggravate this dilemma. We generated weather based on historical and projected future climate in South-eastern and Central Norway. Using this weather data as input, we simulated spring workability, attainable yield, timeliness costs, and mechanization management with a workability model and a mechanization model. The projected climate changes resulted in improved workability for spring fieldwork and higher attainable yield in South-eastern Norway, and either positive or negative changes in Central Norway compared to historical conditions. We observed a general increase in variability of workability and attainable yield, and a larger risk of extremely unfavourable years in the most unfavourable scenarios in Central Norway. Changes in profitability and mechanization management were small, but followed the same pattern. The negative effects in the most unfavourable climate scenarios in Central Norway were in contrast to positive effects in earlier studies. We explained discrepancies by differences in research methods and purpose. However, simulated sowing dates of annual crops should consider workability of the soil, in terms of water content. Under worst-case conditions, in need of a certain time window to complete their spring fieldwork, farmers might adapt to impaired spring workability by working the soil at higher water content than simulated in our study. The consequence would be a larger loss of attainable yield and less profitability in the future. We anticipate that negative effects may also be expected in other northern cold-temperate regions with high soil water content in spring.

Dynamic heat transfer model and applicability evaluation of aerogel glazing system in various climates of China

Aerogel is a super insulation material and it has absorptivity to solar radiation. Indoor heat gain through aerogel glazing system and its temperature distribution depend strongly on the climatic conditions and geographical position of a building. In this paper, a dynamic heat transfer model and an optical model for granular aerogel glazing system are developed and validated through an experiment. By employing the validated model, the applicability of aerogel glazing system in various climates has been evaluated. By comparing the total heat loss in heating season, it is found that aerogel glazing system has great energy saving potential in Severe Cold Region and Temperate Region. The comparative analysis of total heat gain in cooling season indicates that aerogel glazing system in Hot-Summer Warm-Winter Region performs slightly better than the commonest double glazing system, but inferior to low-e double glazing system. In Cold Region and Hot-Summer Cold-Winter Region, there both have heating and cooling seasons all year round. The sum of total heat loss and total heat gain is used to evaluate the annual applicability. The results show that aerogel glazing system is suitable to apply in Cold Region and in the south and north orientations of Hot-Summer Cold-Winter Region.

Cross-species screening of microsatellite markers for individual identification of snow petrel Pagodroma nivea and Wilson's storm petrel Oceanites oceanicus in Antarctica.

Seabirds are important indicators of marine ecosystem health. Species within the order Procellariiformes are the most abundant seabird species group distributed from warm tropical to cold temperate regions including Antarctica. There is a paucity of information on basic biology of the pelagic seabird species nesting on the Antarctic continents, and long-term studies are required to gather data on their population demography, genetics and other ecological parameters. Under the ‘Biology and Environmental Sciences’ component of the Indian Antarctic programme, long-term monitoring of Antarctic biodiversity is being conducted. In this paper, we describe results of cross-species screening of a panel of 12 and 10 microsatellite markers in two relatively little studied seabird species in Antarctica, the snow petrel Pagodroma nivea and the Wilson's storm petrel Oceanites oceanicus, respectively. These loci showed high amplification success and moderate levels of polymorphism in snow petrel (mean no. of alleles 7.08 ± 3.01 and mean observed heterozygosity 0.35 ± 0.23), but low polymorphism in Wilson's storm petrel (mean no. of alleles 3.9 ± 1.3 and mean observed heterozygosity 0.28 ± 0.18). The results demonstrate that these panels can unambiguously identify individuals of both species (cumulative PIDsibs for snow petrel is 3.7 × 10−03 and Wilson's storm petrel is 1.9 × 10−02) from field-collected samples. This work forms a baseline for undertaking long-term genetic research of these Antarctic seabird species and provides critical insights into their population genetics.

Greenhouse gas emissions from two hydroelectric reservoirs in Mediterranean region.

Water reservoirs are used for many purposes, such as water supply, irrigation, flood mitigation, and hydroelectric energy generation. Although hydroelectric energy is considered "green," many studies show that the construction of a reservoir enhances greenhouse gas (GHG) emissions at the transformed area. These emissions, mainly of CO2, CH4, and N2O gases, depend on the age of the reservoir, landscape and soil composition, fauna and flora remnants of the impounded area, climatic conditions, and basin runoffs. Consequently, GHG emissions significantly vary between reservoirs and depending on local specificities. Several studies have investigated GHG emissions from reservoirs around the world, focusing mainly on reservoirs located in cold regions, temperate regions, and tropical regions. Research is lacking for reservoirs in Mediterranean countries, like Greece, and similar regions. This work initially assesses the net GHG emissions of a newly created reservoir (Ilarion est. 2012) in Western Macedonia, Greece. The methodology for net GHG emission calculation was based on the use of literature data concerning pre-impoundment emission factors and local specificities of the reservoir (terrain type, canopy cover), as well as on the 2-year measurement data that were collected using a "static floating chamber." Furthermore, in this work, the gross GHG emissions of an older, in-line reservoir (Polyfytos est. 1974) were also calculated, based on 2-year measurement data. The results show that the global warming potential (GWP) of the reservoirs is dictated by methane emissions; it minimizes during winter and spring and maximizes during summer and autumn. Hydroelectric energy production at Ilarion Reservoir results in 32 to 97 times less total CO2 equivalent emissions in comparison to fossil fuels, while at Polyfytos Reservoir only 8 to 24 times less (based on gross emissions). It appears that the impact of a reservoir's morphology on GHG emissions is more significant than that of a reservoir's age.

Reproduction and growth of Collembola under snow in a cold temperate region

Reproduction and growth of Collembola under snow in a cold temperate region

How global climate change and regional disturbance can expand the invasion risk? Case study of Lantana camara invasion in the Himalaya

Presently, it is debated if regional conservation efforts can alone resolve the ecological problems that global climatic changes could bring. Biological invasion is one of such concerns. In the present study, we modeled how change in global climate and regional anthropogenic pressure can impact the distribution of invasive Lantana camara in the Upper Ganga valley of the Western Himalaya (India). The forest in the study area was stratified into 1 km2 grid and two 15 m radius plot were located in each of the forest types in the grid, for recording Lantana presence. In total, 2221 plots were sampled covering 22% of forest. We used predictors representing the climate, forest patch size, fire and natural disaster variables for modeling the species distribution using maximum entropy algorithm. We further simulated 12 future landscape scenarios based on the global trends of these parameters. The present species—environment relationship was projected to these future landscape scenarios. Lantana was presently estimated to spread in 231 km2 of the study area. It invaded larger forest patches in the sub-tropical region, and smaller disturbed forest patches in the warm and cold temperate region. Increased distribution of Lantana was projected across all the future scenarios. The study revealed how global climate changes and regional anthropogenic pressure can have a synergistic effect on the expansion of invasive species in the future. It thus questions the efficiency of conducting only regional efforts in absence of global initiative to reduce the greenhouse gases emission.

Allometric differences on the shell shape of two scorched mussel species along the Atlantic South American Coast

Scorched mussels (Bivalvia: Mytilidae) are an important component of rocky shore assemblages around the world. The mussel beds of the mid-intertidal coasts of the south-western Atlantic are composed of two species of scorched mussels, which dominate the physiognomy and structure of the rocky shore communities. The present study investigates the variation in the shell-shape allometric trajectories of both species of mussels throughout their distributional range in the southwestern Atlantic coast, from latitude 34°S to 53°S. Shells of Brachidontes rodriguezii were collected at two Uruguayan localities and four Argentinean localities, while shells of Perumytilus purpuratus were collected at six Argentinean localities. Shell shapes of the specimens were studied by geometric morphometrics using landmark and semi-landmark methods. Different evolutionary histories and thermal regimes characterize these two species. Brachidontes rodriguezii seems to have a long history in the region and is present in a restricted area, the warm temperate region of the south-western Atlantic, while P. purpuratus seems to have a recent history and is present in a wide thermal range, involving the cold-temperate regions of the south-western Atlantic and south-eastern Pacific and the warm-temperate region of the south-eastern Pacific. Based on these considerations, we prompt the hypothesis that allometric trajectories of P. purpuratus shell shape is more variable and adapted to a specific habitat than B. rodriguezii. The impact of allometry was larger in P. purpuratus than in B. rodriguezii. Graphical evidence was gathered, showing that these two species differ in allometric growth forms and that the allometric shell morphology changes reflect environmental constraints and adaptation. While the intertidal mussel beds of the South American coasts are ecologically similar in appearance, we found that the allometric variation of the scorched mussels occurs in response to diverging evolutionary processes such as phenotypic plasticity in P. purpuratus and canalization in B. rodriguezii.