Spring Ephemeral Research Articles

Ephemeral plant indicators of livestock grazing in arid rangelands during wet conditions

Vegetation communities in arid rangeland systems are typically dominated by short-lived, ephemeral (annual) plants during periods of high rainfall. These conditions present a rare opportunity to examine herbivore–plant interactions and identify potential indicators of grazing intensity. The influence of cattle grazing on vegetation communities of arid cracking-clay gibber-gilgai systems in Australian rangelands was investigated during La Niña (wet) conditions, including 2010, which was the wettest year on record in the region. Seasonal annual plant diversity was assessed at three grazed and three less-grazed sites. Individual annual species’ responses to grazing intensity were examined among grazed and less-grazed sites (i.e. increasing or decreasing response). Additionally, rare (found at one site only) and restricted (found at grazed or less-grazed sites only) annual and perennial species were identified to elucidate their status as indicators. Prevailing La Niña conditions allowed the study of little-known, short-lived species, which constituted the bulk of species richness. Differences in grazing intensity were more clearly ascertained from examining individual species than plant diversity. Of 31 annual/short-lived species, 21 responded to grazing intensity. Although most species responded to grazing (n = 7 increasers and n = 14 decreasers), these responses did not necessarily reflect published accounts of their so-called palatability. Thirty other species were restricted to certain site types (grazed or less-grazed) and 20 were rare. The indicator species concept should be applied at appropriate scales, and more detailed information is needed on stock preferences for these ephemeral plants in these rangeland systems. Elucidating the effect of grazing on individual plant species’ phenology, and identifying indicators, is important for developing efficacious land management practices.

Strong potential for endozoochory by waterfowl in a rare, ephemeral wetland plant species, Astragalus contortuplicatus (Fabaceae)

It was proposed previously that passive dispersal by migratory aquatic birds explain the widespread distribution of many wetland organisms. Several experimental studies have shown that many widespread wetland plant species can be readily dispersed within the guts of Anatidae. However, it is unclear whether plants with a more restricted distribution are able to disperse via waterbirds. This paper addresses the dispersal ability and germination ecology of the little-known Hungarian milkvetch <em>Astragalus contortuplicatus</em>, which occurs on banks of continental rivers and has a limited and unpredictable distribution. To test whether limited capacity for endozoochory by waterfowl could explain the sporadic appearance of this species, we force-fed ten captive mallards (<em>Anas platyrhynchos</em>) with 100 milkvetch seeds each. Droppings were collected for up to 45 h after feeding. Intact and viable seeds were found in the droppings of each mallard, and altogether 24.7% of seeds fed were recovered intact. The proportion of retrieved seeds that germinated (27.0%) was significantly higher than that of untreated control seeds (0.5%), but significantly lower than that of mechanically scarified seeds (96.0%). Retrieved seeds that germinated developed into healthy mature plants. Given the average flight velocity of mallards, seeds of <em>A. contortuplicatus</em> may travel up to 1600 km inside the digestive tract of migrating individuals. Our results suggest that avian vectors may be more important for the dispersal of rare higher plants (especially those with a hard seed-coat) than hitherto considered. Moreover, they suggest that rarity does not necessarily indicate limited dispersal ability, and may instead be explained by specific habitat requirements.

Resolution of Respect: Paul Risser, 1939–2014

Resolution of Respect: Paul Risser, 1939–2014

Ephemeral plants mediate responses of ecosystem carbon exchange to increased precipitation in a temperate desert

The ecological consequences of increased precipitation on ecosystem carbon (C) exchange are gaining increasing concern, especially in the context of ongoing climate change in temperate deserts. In this study, a field manipulative experiment was conducted to assess the effects of increased precipitation and nitrogen (N) addition on net ecosystem C exchange (NEE) in a temperate desert in northwestern China during two years with contrasting precipitation patterns (2011 and 2012). Increased precipitation decreased ecosystem C release by nearly 50% in the wet year of 2011, whereas ecosystem C release was increased in the dry year of 2012 because of the disproportional stimulation of gross ecosystem productivity (GEP) and ecosystem respiration (ER) by increased precipitation. N addition had no impact on NEE because of the slight responses of both GEP and ER to N addition. During the wet year, most of the precipitation occurred during the growing season of ephemeral plants, which profoundly stimulated plant growth and led to a higher response of GEP than ER to increased precipitation. As a result, positive effects of increased precipitation on NEE occurred in this year. During the dry year, the majority of the precipitation fell post the ephemeral growing season and only a small increase in herb biomass was observed. However, the response of ER to increased precipitation was larger than that of GEP, leading to a more negative NEE in 2012, as compared to 2011. C release was thus stimulated by increased precipitation in 2012. Irrespective of precipitation treatment, N addition weakly decreased C release because of the negligible stimulation of GEP and ER, as well as the slight response of ephemeral biomass. The responses of NEE to increased precipitation showed no difference between interplant spaces and beneath the dominant shrubs because of the similar responses of plant growth, GEP and ER between sites. Overall, this study shows that the responses of NEE to projected increasing precipitation depend on the coupling of precipitation timing and plant growing season.

Arbuscular mycorrhizal fungi improved plant growth and nutrient acquisition of desert ephemeral Plantago minuta under variable soil water conditions

Desert ephemeral plants play an important role in desert ecosystem. Soil water availability is considered as the major restrictive factor limiting the growth of ephemeral plants. Moreover, arbuscular mycorrhizal fungi (AM fungi) are widely reported to improve the growth of desert ephemerals. The present study aimed to test the hypothesis of that AM fungi could alleviate drought stress of desert ephemeral Plantago minuta, and AM fungal functions reduced with the improvement of soil water content. A pot experiment was carried out with three levels of soil water contents (4.5%, 9.0%, and 15.8% (w/w)), and three AM inoculation treatments (Glomus mosseae, Glomus etunicatum and non-inoculation). The results indicate that mycorrhizal colonization rate decreased with the increase of soil water availability. Inoculation improved plant growth and N, P and K acquisition in both shoots and roots regardless water treatments. When comparing the two fungi, plants inoculated with G. mosseae performed better than those inoculated with G. etunicatum in terms of plant growth and nutrient acquisition. These results showed that ameliorative soil water did not suppress arbuscular mycorrhizal fungal functions in improving growth and nutrient acquisition of desert ephemeral Plantago minuta.

Relative performance on test and target plants in laboratory tests predicts the risk of non-target attack in the field for arthropod weed biocontrol agents

We tested the hypothesis that quantifying the relative performance of candidate weed biocontrol agents on test and target plants during laboratory host-range testing can predict the probability of test plants being attacked in the field. For arthropod weed biocontrol agents established in New Zealand between 1929 and 2010, the probability of host use was positively correlated with relative performance for both no-choice starvation tests and no-choice oviposition tests. Moreover, multiplying together the relative performance scores for no-choice starvation and oviposition tests to create a combined risk score for no-choice tests resulted in a clear-cut threshold indicating that for scores between 0.21 and 0.33 the probability of host use (including minor spillover attack) occurring rose from close to zero to a virtual certainty. Choice oviposition test data showed a similar pattern to no-choice data, except there were two cases where host use occurred in the field on plant species that had very low relative performance scores in the choice tests. Both of these cases were associated with asynchrony between seed-feeding biocontrol agent activity and the reproductive phenology of the target plant, indicating that choice tests may be inappropriate for certain guilds of biocontrol agent that attack ephemeral plant structures.We conclude that quantitative laboratory testing data can help predict risk of non-target attack. The ability to refer to threshold relative performance scores when deciding whether an agent is safe to release has the potential to ensure fewer environmentally safe candidate biocontrol agents are erroneously rejected, thereby enhancing efficiency in the selection and approval of new agents.

Causes of seedling mortality in desert for the small xeric tree Haloxylon ammodendron

The destroyed vegetation dominated by Haloxylon ammodendron (C. A. Mey.) Bunge resulted in more moving sand dunes in Gurbantunggut Desert of Northwest China. Natural vegetation restoration is difficult due to high seedling mortality of H. ammodendron, which has unclear causes. Two independent field experiments on relationships between key environmental factors and survival of H. ammodendron seedlings were carried out in Gurbantunggut in the spring of 2008 and the summer of 2009. The spring experiment suggested that the number of ephemeral plants was significantly increased with more precipitation, and they competed for water and reduced survival of H. ammodendron seedlings. The highest H. ammodendron seedling survival was for treatment with least precipitation, though the differences were not significant among treatments. The summer experiment showed that variation in seedling mortality was well explained by water content in 0–20 cm layer. It is concluded that in spring, competition for soil water from ephemeral plants is the primary determinant of seedling survival. In summer, without competition of ephemeral plants, seedling survival was mainly determined by drought, which can be either drought of the soil or dryness of the air: when the soil moisture content at upper layer was <1.25%, dryness of the air governed the seedling mortality, otherwise the dryness of the soil governed the seedling mortality.

Scale‐dependent thresholds in the dominant controls of wildfire size in semi‐arid southwest Australia

We aimed to characterize the size distribution of naturally occurring wildfires and to determine how fuel characteristics influence wildfire size in a vegetation mosaic of shrublands and woodlands in semi‐arid southwest Australia. The shape of frequency‐size distributions of fires can be used to elucidate shifts in the dominant drivers or constraints of fire size. We modeled the cumulative frequency‐size distribution of wildfires in southwest Australia using a segmented linear model with two break points. Three fire size categories were defined by the break points of the segmented model: “small” (&lt;2,286 ha), “medium” (2,286–41,020 ha), and “large” fires (&gt;41,020 ha). Break points were interpreted as thresholds in fire size that may represent shifts in the dominant controls of fire spread.We tested whether the influence of fuel characteristics on fire spread varied among fire size categories by comparing the composition of vegetation types and fuel ages among burnt and adjacent unburnt areas using selection ratios (ωx).Small and medium fires burnt shrub‐dominated vegetation types in proportion to their availability (ωx ≈ 1), but tended to burn smaller proportions of sparsely‐vegetated woodlands (ωx &lt; 0.62). In contrast, large fires tended to burn woodlands in proportion to their availability (ωx ≈ 1). Young fuels (&lt;20 years) were under‐represented in burnt areas regardless of fire size (ωx &lt; 0.62), while older fuels (&gt;30 years) burnt in proportion to their availability (ωx ≈ 1).Fire size in semi‐arid southwest Australia is generally limited by fuel mass in recently burnt areas and by fuel continuity in sparsely vegetated woodlands. However, following unusually wet years and subsequent growth of ephemeral plants, fuels in woodland vegetation likely become spatially continuous and capable of supporting the spread of large fires.

English

In order to study the structure of herbaceous biodiversity and its effect factors in broad-leaved Korean pine forest, a total of 100 1-m2 sub-plots were established in the 1 ha site which was monthly investigated from May to September in 2009. Data on soil attributes were also investigated (soil organic matter, available nitrogen, available phosphorus, available potassium, soil, water and pH) without light environment (leaf area index (LAI), photosynthetic photon flux density (PPFD) and, canopy presence). In this paper, the relationships between different layers (tree, shrub and herbaceous), soil attributes and light environment were analyzed. The effects of tree and shrub layers, soil attributes and light environment on the structure of herbaceous diversity were also discussed. The results show that there is an obvious seasonal dynamic for the herb in broad-leaved Korean pine forest. It was dominated by Anemone amurensis (Korsh.) Kom. and Corydalis ambigua Cham. et Schltdl. in May. The highest species richness was in June, when spring ephemeral, early and late-summer plant grew at the same time.&nbsp;July was the growing season and had highest diversity. From August to September, summer plant became withered gradually. There is a significant positive correlation between the diversity in shrub and herb layer Density of shrub layer positively correlated with the cover of herb layer, but negatively correlated with the diversity of herbaceous layer. The effect of the tree layer on the cover and the diversity of herbaceous layer did not arrive at the significant level. The correlation analysis of the cover, diversity and soil attributes, light environment at herbaceous layer, as well as the tree and shrub layer, indicated that available potassium, PPFD, soil water was the key connection between the tree- and shrub layer. The site locates in the broad-leaved Korean pine forest belonged to the old forest which could explain why the tree layer was not related to herbaceous layer in this paper.&nbsp;&nbsp;Therefore, it could be concluded that, the influence of the tree layer on the structure of herbaceous biodiversity carried out through the direct effect on light environment, precipitation and litter. &nbsp; Key words: Tree layer, shrub layer, herbaceous layer, seasonal dynamic, soil attributes, light environment.

Biomass allocation and leaf stoichiometric characteristics in four desert herbaceous plants during different growth periods in the Gurbant&amp;uuml;ngg&amp;uuml;t Desert, China

Aims Plant biomass allocation and elemental homeostasis have recently become a focus in ecological studies. Herbaceous plants are a major component of species diversity in desert ecosystems. Study on biomass allocation and leaf stoichiometry with growth will be beneficial to further understanding the survival strategy and functional features of desert herbs. Methods Four dominant species, including two ephemeral plants (Erodium oxyrrhynchum and Hyalea pulchella) and two annals (Agriophyllum squarrosum and Ceratocarpus arenarius), were selected for in situ and multiple- time investigations. Changes in the characteristics of biomass allocation and leaf N-P stoichiometry, as well as their relationships were analyzed. Important findings Root to shoot ratio decreased gradually during the accumulation of plant biomass in all the four species. The allometric relationships between above- and belowground biomass, however, varied among the four species; the allometric scaling exponents in H. pulchella and C. arenarius initially increased and then de- creased, and tended to become stable toward the later period, whereas the allometric scaling exponents in E. oxyrrhynchum and A. squarrosum initially increased and then tended to be isometry in later period. The leaf N and P contents tended to increase in H. pulchella, but declined in other three species with growth, indicating that the leaf N-P stoichiometry of the plants studied changed and showed weak correlations with biomass indices.

Patterns of grassland productivity, composition and seed abundance, and the diet of the flock bronzewing pigeon Phaps histrionica at one site in northern Australia over a period of marked seasonal change

Context Multiple scales of research are needed to understand the ecology and conservation requirements of species whose ecology is characterised by marked spatial and temporal dynamism. The flock bronzewing pigeon may provide a model for the conservation management of species with similar dispersive ecologies. Aims This study aimed to document the species composition and its variability in seeds consumed by flock bronzewing pigeons across a period of contrasting seasonal conditions, and to relate this diet to variation in food resource availability. Methods The diet of the flock bronzewing pigeon was described by analysis of the crop contents of samples collected over the period from June 2006 to September 2007 at one pastoral property on the Barkly Tablelands, Northern Territory. Variation in food resource availability was assessed using data from remote sensing, grassland community structure, and direct measurement of soil seed density. Multivariate statistical methods were used to test variation in plant community structure between years and among land units; generalised linear modelling was used to examine inter-annual variation in the abundance of key food plant species and seasonal variation in seed abundance. Key results Across the period of this study, the diet of flock bronzewing pigeons on the Barkly Tableland was largely restricted to seeds of a small number of plant species within Mitchell grasslands. Dietary patterns varied between years; evidence from remote sensing, grassland community structure, and seed density was consistent with these dietary patterns. Conclusions Flock bronzewing pigeons appear to be adapted to exploiting rare, episodic events, leading to high seed production by the ephemeral or annual component of perennial tussock grasslands. Key food plant species include the forbs Wedelia asperrima, Trichodesma zeylanicum and Phyllanthus lacerosus and the large-seeded annual grass Chionachne hubbardiana. These species may not be those that provide critical resources during unfavourable periods. Implications Conservation management of flock bronzewing pigeons will entail strategies to maintain key food species in grazed landscapes, and to ensure replenishment of seed reserves of annual and ephemeral plant species. Management practices to achieve these goals may include rotational wet season spelling of paddocks. More information is required on the focal areas for persistence within these black-soil grassland landscapes.

Cloning of a vacuolar H + -pryophosphatase gene from emphemeral plant Olimarabidopsis pumila whose overexpression improve salt tolerance in tobacco

Olimarabidopsis pumila is a close relative of the model plant Arabidopsis thaliana but, unlike A.thaliana , it is a salt-tolerant ephemeral plant that is widely distributed in semi-arid and semi-salinized regions of the Xinjiang region of China, thus providing an ideal candidate plant system for salt tolerance gene mining. The vacuolar H + -translocating inorganic pyrophosphatase (V-H + -PPase) is an electrogenic proton pump that play pivotal role in translocating protons into vacuoles in plant cells. A V-H + -PPase gene, OpVP , was isolated from O. pumila in this study. The OpVP cDNA has an open reading frame of 2 313 bp, encoding a polypeptide of 770 amino acid residues with an estimated molecular mass of 80.7 kDa. The OpVP shows high amino acid similarity with other Brassicaceae V-H + -PPase genes. Expression profiles under salt and drought treatment, abcisic acid (ABA), indole-3-aceticacid (IAA) and gibberellins (GA) induction were investigated, and the results reveal that the expression of OpVP was induced in leaves under treatment with salt, drought, ABA, IAA and GA3. Overexpression of the OpVP gene confers enhanced salt tolerance to the transformed tobacco. Transgenic tobacco grows well in the presence of 200 mM NaCl, while wild-type plants exhibit chlorosis and growth inhibition, even death. Compared with wild-type, transgenic plants accumulated more Na + in leaves. Moreover, the leaves of transgenic plants retain higher chlorophyll content during salt stress. This study shows that OpVP is a potential gene for salt tolerance, and can be used in future for developing salt tolerant crops. Key words: H + -pyrophoshatase, Olimarabidopsis pumila , salt, abiotic stress.

Construction of a cDNA Library from the Ephemeral Plant Olimarabidopsis pumila and Preliminary Analysis of Expressed Sequence Tags

Olimarabidopsis pumila is a close relative of the model plant Arabidopsis thaliana but, unlike A. thaliana, it is a salt-tolerant ephemeral plant that is widely distributed in semi-arid and semi-salinized regions of the Xinjiang region of China, thus providing an ideal candidate plant system for salt tolerance gene mining. A good-quality cDNA library was constructed using cap antibody to enrich full-length cDNA with the gateway technology allowing library construction without traditional methods of cloning by use of restriction enzymes. A preliminary analysis of expressed sequence tags (ESTs) was carried out. The titers of the primary and the normalized cDNA library were 1.6 x 10(6) cfu/mL and 6.7 x 10(6) cfu/mL, respectively. A total of 1093 clones were randomly selected from the normalized library for EST sequencing. By sequence analysis, 894 high-quality ESTs were generated and assembled into 736 unique sequences consisting of 72 contigs and 664 singletons. The resulting unigenes were categorized according to the gene ontology (GO) hierarchy. The potential roles of gene products associated with stress-related ESTs are discussed. The 736 unigenes were similar to A. thaliana, A. lyrata, or Thellungiella salsuginea. This research provides an overview of the mRNA expression profile and first-hand information of gene sequence expressed in young leaves of O. pumila.

The limited role of snow water in the growth and development of ephemeral plants in a cold desert

AbstractQuestionThe ephemeral layer is an important component of the plant community in cold deserts. Conventional wisdom has it that the ephemeral layer primarily depends on early spring snowmelt water for germination and development. However, this hypothesis has never been subjected to rigorous testing.LocationSouthern edge of the Gurbantunggut Desert, a cold desert and a natural habitat of ephemeral plants (the inter‐sand dune lowland), in the far northwest of China and around the geographical centre of the Eurasian continent.MethodsAt the end of the snow cover season between 2009 and 2011, four different snow treatments (0, 50, 100 and 200% snow cover, with 100% representing the natural amount of snow) were applied, using five replicates. Seedling establishment, species diversity and plant growth, population, cover and productivity were monitored throughout or sampled at the end of the growing season.ResultsThe ephemeral plant germination and seedling density were significantly influenced by changes in snow cover. Germination, density of mature ephemeral plants and plant coverage rose as snow cover depth increased. However, the height, rooting depth, numbers of lateral roots and above‐ground biomass of individual plants decreased as snow cover increased, and plant size was negatively correlated with plant density. At the ephemeral layer level, above‐ground biomass showed no significant variation between snow treatments. There was also no significant difference in species richness among the snow treatments.ConclusionsIncreased snow resulted in higher plant density of ephemerals. However, this high density induced strong competition, reducing the body size of individual plants. By the end of the growing season, snow treatments did not induce significant changes in primary productivity of the ephemeral layer. Primary productivity or growth after seedling establishment depended mainly on rainfall that occurred after the snow had melted, not on snowmelt water itself. Thus conventional wisdom was shown to be only partially true. Snow was important to these ephemeral plants, but its role was limited to seedling establishment.

Generalized additive mixed models for disentangling long‐term trends, local anomalies, and seasonality in fruit tree phenology

Quantifying temporal patterns of ephemeral plant structures such as leaves, flowers, and fruits gives insight into both plant and animal ecology. Different scales of temporal changes in fruits, for example within- versus across-year variability, are driven by different processes, but are not always easy to disentangle. We apply generalized additive mixed models (GAMMs) to study a long-term fruit presence–absence data set of individual trees collected from a high-altitude Afromontane tropical rain forest site within Bwindi Impenetrable National Park (BINP), Uganda. Our primary aim was to highlight and evaluate GAMM methodology, and quantify both intra- and interannual changes in fruit production. First, we conduct several simulation experiments to study the practical utility of model selection and smooth term estimation relevant for disentangling intra- and interannual variability. These simulations indicate that estimation of nonlinearity and seasonality is generally accurately identified using asymptotic theory. Applied to the empirical data set, we found that the forest-level fruiting variability arises from both regular seasonality and significant interannual variability, with the years 2009–2010 in particular showing a significant increase in the presence of fruits-driven by increased productivity of most species, and a regular annual peak associated occurring at the end of one of the two dry seasons. Our analyses illustrate a statistical framework for disentangling short-term increases/decreases in fruiting effort while pinpointing specific times in which fruiting is atypical, providing a first step for assessing the impacts of regular and irregular (e.g., climate change) abiotic covariates on fruiting phenology. Some consequences of the rich diversity of fruiting patterns observed here for the population biology of frugivores in BINP are also discussed.

Combined effects of snow depth and nitrogen addition on ephemeral growth at the southern edge of the Gurbantunggut Desert, China

Water and nitrogen (N) inputs are considered as the two main limiting factors affecting plant growth. Changes in these inputs are expected to alter the structure and composition of the plant community, thereby influencing biodiversity and ecosystem function. Snowfall is a form of precipitation in winter, and snow melting can recharge soil water and result in a flourish of ephemerals during springtime in the Gurbantunggut Desert, China. A bi-factor experiment was designed and deployed during the snow-covering season from 2009 to 2010. The experiment aimed to explore the effects of different snow-covering depths and N addition levels on ephemerals. Findings indicated that deeper snow cover led to the increases in water content in topsoil as well as density and coverage of ephemeral plants in the same N treatment; by contrast, N addition sharply decreased the density of ephemerals in the same snow treatment. Meanwhile, N addition exhibited a different effect on the growth of ephemeral plants: in the 50% snow treatment, N addition limited the growth of ephemeral plants, showing that the height and the aboveground biomass of the ephemeral plants were lower than in those without N addition; while with the increases in snow depth (100% and 150% snow treatments), N addition benefited the growth of the dominant individual plants. Species richness was not significantly affected by snow in the same N treatment. However, N addition significantly decreased the species richness in the same snow-covering depth. The primary productivity of ephemerals in the N addition increased with the increase of snow depth. These variations indicated that the effect of N on the growth of ephemerals was restricted by water supply. With plenty of water (100% and 150% snow treatments), N addition contributed to the growth of ephemeral plants; while with less water (50% snow treatment), N addition restricted the growth of ephemeral plants.

Testing fertilizer, gypsum, planting season and varieties of wild leek (Allium tricoccum) in forest farming system

Wild leek (Allium tricoccum) is an edible spring ephemeral of the eastern deciduous forests of North America that takes advantage of the short period of high light conditions between snowmelt and canopy closure to accumulate the carbon required to complete its annual growth and seed production. In Quebec (Canada), this slow-growing species has been subjected to great harvesting pressure, which forced the provincial government to ban commercial harvest and sales in 1995. An illegal market has since developed and the plant is still under threat. Conservation of existing natural populations might be possible through commercial production of wild leek. To investigate this possibility, we set up plots in four sugar maple forest stands where different organic fertilizer and gypsum (0 or 3,000 kg ha−1) applications were tested, together with two wild leek varieties, and bulb planting season. The two varieties, tricoccum and burdickii, despite morphological differences, are both suitable for cultivation. Planting bulbs in the spring seems more advantageous than in autumn, but these results will need to be confirmed. Fertilized plants exhibited better growth the year following transplantation than did non-fertilized plants. Belowground:aboveground biomass ratios indicated that plants receiving more fertilizer produced larger bulbs, but leaf size did not differ statistically. According to leaf nutrient analysis, fertilizers would need to be applied each year, whereas gypsum (as a calcium source) can be applied less frequently. Our results indicated a high potential for wild leek as a forest crop, at least when the bulbs are planted.

Long‐term monitoring of mammals in the face of biotic and abiotic influences at a semiarid site in north‐central Chile

AbstractThe data set covers a 16‐year period (1989–2005) of monthly small‐mammal surveys and associated habitat and environmental data. Small mammals are trapped every month on all experimental plots, and both ephemeral and perennial plant cover and soil seed bank composition are measured at regular intervals. Rainfall is recorded and compiled annually (through 1998) or monthly; information on captured small mammals and on all vegetative and rainfall data is contained in associated files. These data have been applied to diverse population‐ and community‐level analyses and remain useful for investigations of population dynamics, species interactions, and the relative influence of biotic and abiotic factors. Sampling is ongoing, and data will be added over time.

Effects of Commercial Harvesting on Population Characteristics and Rhizome Yield of Anemone altaica

Effects of Commercial Harvesting on Population Characteristics and Rhizome Yield of Anemone altaica. Commercial harvesting constitutes a direct threat to numerous non–timber forest products (NTFPs), but its ecological effects have not been well documented. Anemone altaica Fisch. ex C. A. Mey, a spring ephemeral plant found in temperate forests of Eurasia, is a traditional Chinese herb. Owing to medicinal value, its rhizomes have been harvested for commercial purposes in northwestern China for many years. This paper addresses the ecological effects of commercial harvesting on A. altaica populations under different harvest intensities. The results show that size–selective harvesting of rhizomes can increase population densities by asexual propagation. Currently, two– to three–year–old individuals derived from asexual propagation are the main targets of commercial harvesting. The increased demand in recent years has resulted in earlier and more intensive harvesting activities largely impacting the natural recovery of the harvested populations. For sustainable use of this traditional medicinal species, we recommend that a periodic harvest strategy of three to four years be adopted.

Construction of a cDNA Library from the Ephemeral Plant Olimarabidopsis pumila and Preliminary Analysis of Expressed Sequence Tags

Construction of a cDNA Library from the Ephemeral Plant Olimarabidopsis pumila and Preliminary Analysis of Expressed Sequence Tags