Oxygen Distribution in Wetland Plant Roots and Permeability Barriers to Gas-exchange with the Rhizosphere: a Microelectrode and Modelling Study with Phragmites australis

Adventitious roots of intact Phragmites plantlets were securedhorizontally 2–3 mm below the surface of an oxygen-depletedfluid agar across which oxygen-free nitrogen was gently streamedto create a constant oxygen sink; the leafy shoot was fullyexposed to air. Radial oxygen profiles through rhizosphere androot at different distances from the apex were obtained polarographicallyusing Clark-type bevelled microelectrodes servo-driven in stepsof 10 µm (root) or 10–50 µm (rhizosphere).The pattern of radial oxygen loss (ROL) typical of wetland plants,viz. high at the apex and declining sharply sub-apically, wasrelated to synergism between ROL, and oxygen consumption andincreasing impedance to diffusion within the epidermal/hypodermalcylinder rather than to a surface resistance. The smallest oxygendeficit (2 kPa) to develop across the 80 µm thick epidermal/hypodermalcylinder was within the apical 10 mm and was consistent withtissue oxygen diffusivities similar to water. At 100 mm fromthe apex, consumption and impedance had increased the deficitto about 15 kPa and reduced ROL almost to zero. The developingimpedance within the epidermal/hypodermal cylinder was leastin cell layers immediately adjoining the cortex and increasedmost in the hypodermal cell layer abutting the epidermis. Thesub-apical decline in ROL appeared to coincide with the appearanceof aerenchyma in the cortex but thin walled ‘passage areas’(windows) in the hypodermal/epidermal cylinder persisted locallyand remained leaky to oxygen to some degree. It is through thesewindows that lateral roots emerge and the cortex in line withthe windows remains non-aerenchymatous. The radial and longitudinaloxygen profiles were consistent with modelling predictions.The shapes of the stelar oxygen profiles were consistent witha higher oxygen demand in the outer region (viz. pericycle,phloem, protoxylem and early metaxylem cylinder) than in theinner core (late metaxylem cylinder and medulla), but the deficitswere relatively small (     

A Method to Estimate Practical Radial Oxygen Loss of Wetland Plant Roots

The estimation of practical radial oxygen loss (ROL) of wetland plant roots was attempted in this study. We have devised a new method to measure ROL of wetland plant roots. The whole root system was bathed in an anoxic nutrient solution. Oxygen released from the root was removed immediately by introducing oxygen-free nitrogen gas (O₂ < 4 nmol L⁻¹) to mimic natural habitats where released oxygen is consumed rapidly due to chemical and biological oxidation processes. Oxygen removed from the root-bathing chamber was simultaneously detected colorimetrically by use of the highly oxygen-sensitive anthraquinone radical anion (AQ·⁻) in a cell outside the root-bathing chamber, which decolorized by a rapid reaction with oxygen. An emergent macrophyte Typha latifolia L. was incubated, and its ROL was measured by both the new method and one of the conventional methods, the closed chamber/electrode method, by which the ROL of Typha latifolia L. had not yet been measured. The new method succeeded in detecting the ROL, whereas the conventional method was not able to detect oxygen, due to the level being below the detection limit of the oxygen electrode. The oxygen supply via the seedlings of Typha latifolia L. was ca. 10 times higher compared with control measurements without plant. Light illumination significantly enhanced the ROL of Typha latifolia L. (0.33 nmol O₂ g⁻¹ root dry weight s⁻¹ under light and 0.18 nmol O₂ g⁻¹ root dry weight s⁻¹ in the dark). Theses values fall between those previously reported by the closed chamber/titanium citrate method and the open chamber/electrode method.     

杭州湾湿地不同演替阶段优势物种光合生理生态特性

采用LI-6400光合作用系统测定了杭州湾滨海湿地不同演替阶段6种优势植物-包括早期植物海三棱藨草(Scirpus mariqueter)和糙叶苔草(Carex scabrifolia)、中期植物芦苇(Phragmites communis)和柽柳(Tamarixchinensis)、后期植物白茅(Imperata cylindrica)和旱柳(Salix matsudana)的光合作用光响应曲线(LRC)和CO2响应曲线(A/Ci),并拟合得出多个光合生理指标.结果表明,6种优势植物LRC净光合速率(Pn)大小顺序为海三棱藨草>糙叶苔草>芦苇>柽柳>白茅>旱柳,且早期植物显著大于后期植物(P<0.05);光补偿点(LCP)、光饱和点(LSP)、最大净光合速率(Amax)、和暗呼吸速率(Rd)变化与Pn相同,也表现出演替早期植物>中期植物>后期植物;而表观量子效率(AQY)则表现出相反趋势.由A/Ci曲线可以发现,演替早期优势植物较后期植物具有更低的CO2羧化效率(CCE)和相对较高的CO2补偿点(CCP).可见群落演替与各阶段优势植物的光合生理特征密切相关.     

Species Distribution Models for Crop Pollination: A Modelling Framework Applied to Great Britain

Insect pollination benefits over three quarters of the world''s major crops. There is growing concern that observed declines in pollinators may impact on production and revenues from animal pollinated crops. Knowing the distribution of pollinators is therefore crucial for estimating their availability to pollinate crops; however, in general, we have an incomplete knowledge of where these pollinators occur. We propose a method to predict geographical patterns of pollination service to crops, novel in two elements: the use of pollinator records rather than expert knowledge to predict pollinator occurrence, and the inclusion of the managed pollinator supply. We integrated a maximum entropy species distribution model (SDM) with an existing pollination service model (PSM) to derive the availability of pollinators for crop pollination. We used nation-wide records of wild and managed pollinators (honey bees) as well as agricultural data from Great Britain. We first calibrated the SDM on a representative sample of bee and hoverfly crop pollinator species, evaluating the effects of different settings on model performance and on its capacity to identify the most important predictors. The importance of the different predictors was better resolved by SDM derived from simpler functions, with consistent results for bees and hoverflies. We then used the species distributions from the calibrated model to predict pollination service of wild and managed pollinators, using field beans as a test case. The PSM allowed us to spatially characterize the contribution of wild and managed pollinators and also identify areas potentially vulnerable to low pollination service provision, which can help direct local scale interventions. This approach can be extended to investigate geographical mismatches between crop pollination demand and the availability of pollinators, resulting from environmental change or policy scenarios.     

Distribution and Ecophysiology of Calanoid Copepods in Relation to the Oxygen Minimum Zone in the Eastern Tropical Atlantic

Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (0–1800 m) at eight stations in the eastern tropical Atlantic (3°47′N to 18°S) during three expeditions in 2010 and 2011. Their horizontal and vertical distribution was determined and related to the extent and intensity of the OMZ, which increased from north to south with minimum O₂ concentrations (12.7 µmol kg⁻¹) in the southern Angola Gyre. Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth. Maximum copepod biodiversity was observed in the deep waters of the central Angola Basin. Respiration rates and enzyme activities were measured to reveal species-specific physiological adaptations. Enzyme activities of the electron transport system (ETS) and lactate dehydrogenase (LDH) served as proxies for aerobic and anaerobic metabolic activity, respectively. Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature. Copepods of the families Eucalanidae and Metridinidae dominated within the OMZ. Several of these species showed adaptive characteristics such as lower metabolic rates, additional anaerobic activity and diel vertical migration that enable them to successfully inhabit hypoxic zones.     

Restoring Wetland Plant Diversity: A Comparison of Existing and Adaptive Approaches

Most restoration projects are not designed or assessed in ways that identify cause–effect relationships.When plants die, even detailed postmortem examinations cannot pinpoint causes; e.g., mortalities of 7% vs. 90% in two salt marsh transplantation projects were attributable to differences in hypersalinity and sedimentation, but other effects could not be ruled out. Adaptive restoration (the experimental testing of alternative approaches in restoration sites), however, can clarify cause–effect relationships, while simultaneously restoring plant diversity and informing future restoration efforts. Projects in Tijuana Estuary (California) and Greene Prairie (Wisconsin) demonstrate the approach: (1) A large field experiment at Tijuana Estuary showed that species-rich plantings of halophytes accelerated the development of ecosystem structure and function (over single-species plantings) while simultaneously vegetating an intertidal plain. The six-species assemblages produced more complex canopies and accumulated more biomass and nitrogen than singlespecies and unplanted plots. (2) Also at Tijuana Estuary, an experiment is testing the ability of tidal creek networks to accelerate revegetation and increase food-web support (via increased growth of plants, invertebrates, and fish) in an 8-ha project that simultaneously restored tidal flushing. (3) In Greene Prairie, the ability to establish 33 native species is being tested as replacements for an invasive grass (Phalaris arundinacea). In each case, the adaptive approach informs both the science and practice of restoration. Without experimentation, restorationists are hard-pressed to explain past mortality and to suggest better methods for restoring structure and function. Adaptive restoration can provide the knowledge required, especially when large projects are implemented as sequential modules with experiments that sequentially provide essential information.     

拉鲁湿地主要植物群落结构及物种多样性

2002年6~9月对拉鲁湿地植物种类、群落结构、生物量以及物种多样性进行了调查研究.结果表明:(1)拉鲁湿地共有植物30科52属85种,主要有芦苇[Phragmites australis(Cav.)Trin.ex Steud.](A)、尼伯尔酸模(RumexnepalensisSpreng)(B)、水葱(Scirpus validusVahl)(C)、穗状狐尾藻(MyriophyllumspicatumL.)(D)、灯芯草(Juncus effususL.)(E)、针叶苔草(CarexonoeiFranch.et Sav.)和黑褐苔草(CarexatrofuscaSchkuhr)(F)、藏北嵩草(KobresialittledaleiC.B.Clarke)(G)、藏蓟[Cirsiumlanatum(Roxb.ex Willd.)Spreng.](H)等8个主要植物群落.(2)在8个主要植物群落中,嵩草群落所含物种数最多,为44种,穗状狐尾藻群落最少,仅8种;芦苇群落生物量最高,为124.5~1 027.0 g/m2,藏蓟群落生物量最低,为124.5~220.5 g/m2;优势种芦苇的生物量最高,为183.5~660.0 g/m2,藏蓟生物量最低,为43.1~76.3 g/m2.(3)各群落的垂直结构特点是:芦苇群落、水葱群落、穗状狐尾藻群落具有挺水层、浮叶层和沉水层,其他群落只具有可分为高、低两层的草本层.(4)在各群落的相似性方面,嵩草群落与藏蓟群落、水葱群落与芦苇群落和尼伯尔酸模群落的相似性要明显高于其他群落,其Jaccard系数分别为0.549 0、0.538 5、0.500 0;芦苇群落、尼伯尔酸模群落、水葱群落、穗状狐尾藻群落与藏蓟群落以及芦苇群落、穗状狐尾藻群落与嵩草群落在建群种上没有相似之处,Jaccard系数为0.     

Responses to Doubled CO2 in Medicago sativa: Studies on Ecophysiology and Simulation Modelling

A world-wide spread forage grass, Medicago sativa, was grown in two open-top chambers maintained at either normal (350 μmol · mol-1) or doubled (700 μmol · mol-1) CO2 concentration, from seedling to maturity. During the whole growth season, ecophysiological measurements and observations were conducted over different phenological stages and the main results were as follows: (1) With similar environmental factors, in terms of RH (relative humidity), irradiance, and watering, a slight shift in temperature (about 0.77℃, averaged over the whole growth season) within the chamber maintained at doubled CO2 did not affect instantaneous physiological processes at leaf level, but had some impacts on the effect of doubled CO2 over a long period. (2) Over the whole growth season, physiological variables showed differences between two chambers. The net photosynthesis of plant grown under higher CO2 increased by 18.7 %, while stomatal conductance fell slightly as compared with that of the control. So was the water use efficiency which was also 30.1% higher than the control. Based on the above results from field studies, we concluded that photosynthetically active radiation (PAR) and RH were the main factors affecting photosynthesis and stomatal behavior. Then we combined a widely accepted model of C3 leaf photosynthesis with an empirical model of stomatal conductance and made some modifications according to our experiments. This model was parameterized using field data sets of net CO2 assimilation, stomatal conductance, intercellular CO2 concentration of plants grown at both doubled and control CO2 levels. Variances of main parameters between two treatments reflected some biochemical changes in leaf cell. The maximum efficiency of light energy conversion (α) increased by 22 % and light-saturated rate of electron transport (Jmax) rose by 15 %. The maximum stomatal conductance was slightly reduced by 8 %. The increases in parameters (α and Jmax) indicate accelerated biochemical processes in leaf cell, which means that the photosynthetic capacity of M. sativa may increase at elevated CO2. These results agree well with biochemical measurements at cell level.     

Germination of Species of Caryophyllaceae in Relation to their Geographical Distribution in Europe

Comparisons were made between the germination responses to temperatureof species of Caryophyllaceae collected in the wild from differentparts of Europe. Species occurring predominantly in the Mediterraneanzone were compared with those distributed in the deciduous woodlandzone of central and southern Europe; steppeland and grasslandareas of eastern Europe, and in the Taiga and Tundra of northernEurope. The geo-botanical distributions of different specieswere reflected in their germination responses. Species fromthe Mediterranean germinated over a range with a mean of 4.5to 24.2 °C; those from deciduous woodland over the range11.8 to 30.0 °C; those from steppelands over the range 6.0to 30.0 °C. There was little uniformity in the northernEuropean species. The significance of the results is discussedin relation to the distribution of different species, the variationwithin a species, and the climatic components of the variousgeo-botanical zones.     

Temporal-Spatial Dynamics in Orthoptera in Relation to Nutrient Availability and Plant Species Richness

Nutrient availability in ecosystems has increased dramatically over the last century. Excess reactive nitrogen deposition is known to negatively impact plant communities, e.g. by changing species composition, biomass and vegetation structure. In contrast, little is known on how such impacts propagate to higher trophic levels. To evaluate how nitrogen deposition affects plants and herbivore communities through time, we used extensive databases of spatially explicit historical records of Dutch plant species and Orthoptera (grasshoppers and crickets), a group of animals that are particularly susceptible to changes in the C:N ratio of their resources. We use robust methods that deal with the unstandardized nature of historical databases to test whether nitrogen deposition levels and plant richness changes influence the patterns of richness change of Orthoptera, taking into account Orthoptera species functional traits. Our findings show that effects indeed also propagate to higher trophic levels. Differences in functional traits affected the temporal-spatial dynamics of assemblages of Orthoptera. While nitrogen deposition affected plant diversity, contrary to our expectations, we could not find a strong significant effect of food related traits. However we found that species with low habitat specificity, limited dispersal capacity and egg deposition in the soil were more negativly affected by nitrogen deposition levels. Despite the lack of significant effect of plant richness or food related traits on Orthoptera, the negative effects of nitrogen detected within certain trait groups (e.g. groups with limited disperse ability) could be related to subtle changes in plant abundance and plant quality. Our results, however, suggest that the changes in soil conditions (where many Orthoptera species lay their eggs) or other habitat changes driven by nitrogen have a stronger influence than food related traits. To fully evaluate the negative effects of nitrogen deposition on higher trophic levels it is essential to take into account species life-history traits.     

Dealing with Noisy Absences to Optimize Species Distribution Models: An Iterative Ensemble Modelling Approach

Species distribution models (SDMs) are widespread in ecology and conservation biology, but their accuracy can be lowered by non-environmental (noisy) absences that are common in species occurrence data. Here we propose an iterative ensemble modelling (IEM) method to deal with noisy absences and hence improve the predictive reliability of ensemble modelling of species distributions. In the IEM approach, outputs of a classical ensemble model (EM) were used to update the raw occurrence data. The revised data was then used as input for a new EM run. This process was iterated until the predictions stabilized. The outputs of the iterative method were compared to those of the classical EM using virtual species. The IEM process tended to converge rapidly. It increased the consensus between predictions provided by the different methods as well as between those provided by different learning data sets. Comparing IEM and EM showed that for high levels of non-environmental absences, iterations significantly increased prediction reliability measured by the Kappa and TSS indices, as well as the percentage of well-predicted sites. Compared to EM, IEM also reduced biases in estimates of species prevalence. Compared to the classical EM method, IEM improves the reliability of species predictions. It particularly deals with noisy absences that are replaced in the data matrices by simulated presences during the iterative modelling process. IEM thus constitutes a promising way to increase the accuracy of EM predictions of difficult-to-detect species, as well as of species that are not in equilibrium with their environment.     

Species Invasiveness in Biological Invasions: A Modelling Approach

The study of invasiveness, the traits that enable a species to invade a habitat, and invasibility, the habitat characteristics that determine its susceptibility to the establishment and spread of an invasive species, provide a useful conceptual framework to formulate the biological invasion problem in a modelling context. Another important aspect is the complex interaction emerging among the invader species, the noninvader species already present in the habitat, and the habitat itself. Following a modelling approach to the biological invasion problem, we present a spatially explicit cellular automaton model (Interacting Multiple Cellular Automata (IMCA)). We use field parameters from the invader Gleditsia triacanthos and the native Lithraea ternifolia in montane forests of central Argentina as a case study to compare outputs and performance of different models. We use field parameters from another invader, Ligustrum lucidum, and the native Fagara coco from the same system to run the cellular automaton model. We compare model predictions with invasion values from aerial photographs. We discuss in detail the importance of factors affecting species invasiveness, and give some insights into habitat invasibility and the role of interactions between them. Finally, we discuss the relevance of mathematical modelling for studying and predicting biological invasions. The IMCA model provided a suitable context for integrating invasiveness, invasibility, and the interactions. In the invasion system studied, the presence of an invader's juvenile bank not only accelerated the rate of invasion but was essential to ensure invasion. Using the IMCA model, we were able to determine that not only adult survival but particularly longevity of the native species influenced the spread velocity of the invader, at least when a juvenile bank is present. Other factors determining velocity of invasion detected by the IMCA model were seed dispersal distance and age of reproductive maturity. We derived relationships between species' adult survival, fecundity and longevity of both theoretical and applied relevance for biological invasions. Invasion velocities calculated from the aerial photographs agreed well with predictions of the IMCA model.     

Ion Distribution in Salt-stressed Mature Zea mays Roots in Relation to Ultrastructure and Retention of Sodium

Ultrastructural features and the distribution of soluble ionshave been examined in mature roots of Zea mays plants grownin both NaCl and Na₂SO₄ salinities. When the plants were grown in either salt, the Na concentrationincreased proximally along the root with a concomitant declinein the K concentration. Both trends were reversed in the shoot. X-ray microanalysis of deep-frozen, fully hydrated specimensshowed that in salt-treated roots Na, and Cl, or S were distributedabout stoichiometrically in the cortex and endodermis. Na wasusually less concentrated than the anion in the lumens of thevessels, but was concentrated markedly relative to either Clor S in the adjoining xylem parenchyma cells. In the older, proximal parts of seminal roots of plants grownboth without salt (controls) and in the presence of either NaClor Na₂SO₄, wall developments occurred in xylem parenchyma cellsat the half-bordered pits in which the cell wall became markedlythicker and possessed a loosely packed fibrillar structure.These structures were not comparable with the transfer-celltype of protuberances reported in the roots of other species. In the xylem parenchyma of plants grown in the presence of Na₂SO₄there were dramatic increases in the quantities of rough endoplasmicreticulum, ribosomes, and mitochondria relative both to controlsand NaCl treatments. The results are discussed in relation to the possible functionof the xylem parenchyma of the mature root in the reabsorptionof Na from the xylem sap, which may mitigate adverse effectsof salinity in salt-sensitive glycophytes.     

杭州西溪和绍兴镜湖国家湿地公园内的维管植物多样性

调查显示,杭州西溪湿地共有维管植物511种,其中蕨类和裸子植物各11种、被子植物489种,隶属于111科352属;绍兴镜湖湿地维管植物384种,其中蕨类12种、裸子植物11种、被子植物361种,隶属于101科285属.两地物种较为丰富.区系成分、生态类型和生长型比较以及β多样性分析均显示,两地有较高的物种相似度,这与两地同处于亚热带东部地区以及相似的人类影响有关.西溪和镜湖的湿地植物分别为280种(54.8%)和200种(52.1%),占据总物种数量的比例较低,是一定程度退化湿地的表现.建议在今后的修复和建设中,多培育湿地环境和湿地植物;同时需保留一定的管理强度,使多样化的生境、丰富有益的动植物物种得以维持,两湿地的生态和社会服务功能得到更好的体现.     

A Soil-free Plant Growth System to Facilitate Analysis of Plant Pathogen Interactions in Roots

Analysis of the interaction of pathogens with plant roots is often complicated by the growth of plants in a soil substrate. A soil-free plant growth system (SPS) was developed that removes the need for a substrate while supporting the growth of seedlings in a nutrient rich, oxygenated environment. The model legume Lupinus angustifolius was used to compare the growth of seedlings within soil and the SPS. Seedlings grown under both conditions were similar in morphology, anatomy and health (measured by leaf chlorophyll abundance) and importantly there was little difference in root growth and development although straighter and fuller root systems were achieved in the SPS. The ease of access to the root system proved efficient for the analysis of root and pathogen interactions with no interference from soil or adhering particulate matter. Following inoculation of L. angustifolius roots with Phytophthora cinnamomi the host/pathogen interaction was easily observed and tissues sampled undamaged.     

A Comparison of the Sucrose Transporter Systems of Different Plant Species

Abstract: The sucrose uptake behaviour of many different plant species is characterised by the presence of at least two components with distinct kinetic properties. These include at least one high-affinity and one low-affinity transport system. All known sucrose transporters from higher plants fall into one of three large subfamilies, according to phylogenetic analysis. Apparently, the largest subfamily, the SUT1 subfamily, exclusively consists of high-affinity sucrose transporters from dicotyledons, whereas none of the transporters from monocotyledonous plants groups within this subfamily. The other two subfamilies of sucrose transporter-like proteins are either low-affinity transporter or putative sucrose-sensing proteins. Most of the known sucrose transporters from monocotyledons are closely related to the SUT2 subfamily and include high-affinity transporters, suggesting a different evolutionary origin of dicotyledonous and monocotyledonous sucrose transporter gene families.     

Fruit Traits in Baboon Diet: A Comparison with Plant Species Characteristics in West Africa

Primate fruit choice among plant species has been attributed to different morphological plant and fruit characteristics. Despite a high abundance of animal-dispersed plant species in the savanna–forest mosaic of West Africa, few data are available on the interplay between morphological fruit traits and primate fruit consumers in this ecosystem. We tested whether olive baboons (Papio anubis) at Comoé National Park, north-eastern Ivory Coast, prefer fruit species with particular characteristics relative to the availability of these traits among the woody plant species at the study site. Specifically we were interested in the suites of traits that best predict fruit choice and seed handling by baboons. The baboons ate fruit/seeds from 74 identified plant species, representing 25 percent of the regional pool of woody plant species. They preferred trees to shrubs and lianas as fruit sources. Otherwise, baboons seemed to consume whatever fruit type, color, and size of fruit and seeds available, though they especially included larger fruit into their diet. Against expectations from the African bird–monkey fruit syndrome of brightly colored drupes and berries, baboons ate mostly species having large, dull-colored fruit. Fruit type and color best described whether baboons included a species into their diet, whereas fruit type and seed size best predicted whether baboons predated upon the seeds of their food plant species. As most plant species at the study site had medium-sized to large fruits and seeds, large frugivores like baboons might be particularly important for plant fitness and plant community dynamics in West African savanna–forest ecosystems.     

Vertical Distribution of Three Namatode Species in Relation to Certain Soil Properties

Population densities of Belonolaimus longicaudatus, Pratylenchus brachyurus, and Trichodorus christiei were determined from soil samples taken weekly in Tifton, Georgia during a 14-month period (except for April and May) at 15-cm increments to a depth of 105 cm. Belonolaimus longicaudatus predominately inhabited the top 30 cm of soil that was 87-88% sand, 6-7% silt, and 5-7% clay. No specimens were found below 60 cm where the soil was 76-79% sand, 5-6% silt, and 15-19% clay. Highest population densities occurred during June through September when temperature in the top 30 cm of soil was 22-25 C and soil moisture was from 9 to 20% by volume. Pratylenchus brachyurus was found at all depths, but population densities were greatest 45-75 cm deep where the soil was 78-79% sand, 6% silt, and 15-16% clay. In the months monitored, highest population densities occurred during March, June, and December when the soil temperature 45-75 cm deep was 14-17 C and soil moisture was 22-42%. Trichodorus christiei was found at all depths, but population densities were highest 30 cm deep where the soil was 83% sand, 5% silt, and 12% clay. Highest population densities occurred during December through March when the soil temperature 30 cm deep was 11-17 C and soil moisture was 18-23%.