Thresholds and Time Lags in Effects of Energy Development on Greater Sage-Grouse Populations

ABSTRACT Rapid expansion of energy development in some portions of the Intermountain West, USA, has prompted concern regarding impacts to declining greater sage-grouse (Centrocercus urophasianus) populations. We used retrospective analyses of public data to explicitly investigate potential thresholds in the relationship between lek attendance by male greater sage-grouse, the presence of oil or gas wells near leks (surface occupancy), and landscape-level density of well pads. We used generalized linear models and generalized estimating equations to analyze data on peak male attendance at 704 leks over 12 years in Wyoming, USA. Within this framework we also tested for time-lag effects between development activity and changes in lek attendance. Surface occupancy of oil or gas wells adjacent to leks was negatively associated with male lek attendance in 5 of 7 study areas. For example, leks that had ≥ 1 oil or gas well within a 0.4-km (0.25-mile) radius encircling the lek had 35–91% fewer attending males than leks with no well within this radius. In 2 of these 5 study areas, negative effects of well surface occupancy were present out to 4.8 km, the largest radius we investigated. Declining lek attendance was also associated with a higher landscape-level density of well pads; lek attendance at well-pad densities of 1.54 well pads/km² (4 well pads/mile²) ranged from 13% to 74% lower than attendance at unimpacted leks (leks with zero well pads within 8.5 km). Lek attendance at a well-pad density of 3.09 well pads/km² (8 well pads/mile²) ranged from 77% to 79% lower than attendance at leks with no well pad within 8.5 km. Further, our analysis of time-lag effects suggested that there is a delay of 2–10 years between activity associated with energy development and its measurable effects on lek attendance. These results offer new information for consideration by land managers on spatial and temporal associations between human activity and lek attendance in sage-grouse, and suggest that regional variation is an important consideration in refining existing management strategies.     

Applications of a Model to Predict the Time to Maturity of Calabrese Brassica oleracea

A model that predicts the time from sowing to maturity of calabreseBrassica oleracea cv. Corvet is used to design a sowing scheduleto give a series of crops maturing at weekly intervals. Thepredicted performance of the sowing schedule is evaluated usingmeteorological data for 14 years recorded at the Scottish CropResearch Institute. In E. Scotland sowings could be made inthe second week of April and continued through until the endof June to provide a regular supply of mature calabrese fromlate July through to early October. There was an increasingrisk of crops failing to mature with progressively later sowingsin July. Continual updating of forecast of harvest date andintervals between harvests, using the current year's weathercombined with long-term average weather, is described. A dynamicsowing plan predicting the best dates to sow, based on theseforecasts, reduced the spread in intervals between harvestsfrom 2·5 to 1·8 days. Model, weather, calabrese, broccoli, thermal time, solar radiation     

Effects of Succession on Nitrogen Export in the West-Central Cascades, Oregon

This study examined impacts of succession on N export from 20 headwater stream systems in the west central Cascades of Oregon, a region of low anthropogenic N inputs. The seasonal and successional patterns of nitrate (NO₃−N) concentrations drove differences in total dissolved N concentrations because ammonium (NH₄−N) concentrations were very low (usually < 0.005 mg L⁻¹) and mean dissolved organic nitrogen (DON) concentrations were less variable than nitrate concentrations. In contrast to studies suggesting that DON levels strongly dominate in pristine watersheds, DON accounted for 24, 52, and 51% of the overall mean TDN concentration of our young (defined as predominantly in stand initiation and stem exclusion phases), middle-aged (defined as mixes of mostly understory reinitiation and older phases) and old-growth watersheds, respectively. Although other studies of cutting in unpolluted forests have suggested a harvest effect lasting 5 years or less, our young successional watersheds that were all older than 10 years still lost significantly more N, primarily as NO₃−N, than did watersheds containing more mature forests, even though all forest floor and mineral soil C:N ratios were well above levels reported in the literature for leaching of dissolved inorganic nitrogen. The influence of alder may contribute to these patterns, although hardwood cover was quite low in all watersheds; it is possible that in forested ecosystems with very low anthropogenic N inputs, even very low alder cover in riparian zones can cause elevated N exports. Only the youngest watersheds, with the highest nitrate losses, exhibited seasonal patterns of increased summer uptake by vegetation as well as flushing at the onset of fall freshets. Older watersheds with lower N losses did not exhibit seasonal patterns for any N species. The results, taken together, suggest a role for both vegetation and hydrology in N retention and loss, and add to our understanding of N cycling by successional forest ecosystems influenced by disturbance at various spatial and temporal scales in a region of relatively low anthropogenic N input.     

Export of Nitrogen,Phosphorus, and Suspended Solids from a Southern New England Watershed to Little Narragansett Bay

The Pawcatuck River watershed (764 km²) is a mainly forested drainage basin with a low population density (80 people km⁻²) that discharges to a shallow estuary, Little Narragansett Bay (RI and CT, USA). In order to quantify the nitrogen (N) and phosphorus (P) flux to the estuary, we measured all forms of nitrogen and phosphorus, as well as suspended solids at the mouth of the river above tidal influence, on more than 80 occasions over an annual cycle. The annual export of total nitrogen, total phosphorus, and total suspended solids amounted to 16.0×10⁶ mol y⁻¹, 0.97×10⁶ mol y⁻¹, and 1.4×10⁶ kg y⁻¹, respectively. Nitrogen export was equally divided between dissolved inorganic (83% NO₃⁻) and organic forms, with particulate nitrogen comprising 17% of the total flux. Phosphorus export was dominated by particulate forms (67%), with dissolved inorganic phosphate contributing 30% and dissolved organic phosphorus contributing 8% of the annual flux. Preliminary nutrient budgets for the Pawcatuck watershed suggest that only about 10% of the nitrogen and phosphorus inputs are exported from the system. Strong regressions between water discharge and TN enabled us to extrapolate the data collected during the relatively dry study period to a long term average discharge year. Under normal river discharge conditions, the N flux would be approximately 26.0×10⁶ mol y⁻¹ or about 20% of the nitrogen inputs to the watershed. This value is very close to the N flux predicted by a regression developed by others from a wide range of larger watersheds. The relatively large size of the Pawcatuck watershed relative to the estuary (9.6 km²), makes Little Narragansett Bay one of the most intensively nitrogen loaded estuaries on the Atlantic coast in spite of the dominant forest cover of the watershed.     

A Simple and Accurate Model to Predict Responses to Multi-electrode Stimulation in the Retina

Implantable electrode arrays are widely used in therapeutic stimulation of the nervous system (e.g. cochlear, retinal, and cortical implants). Currently, most neural prostheses use serial stimulation (i.e. one electrode at a time) despite this severely limiting the repertoire of stimuli that can be applied. Methods to reliably predict the outcome of multi-electrode stimulation have not been available. Here, we demonstrate that a linear-nonlinear model accurately predicts neural responses to arbitrary patterns of stimulation using in vitro recordings from single retinal ganglion cells (RGCs) stimulated with a subretinal multi-electrode array. In the model, the stimulus is projected onto a low-dimensional subspace and then undergoes a nonlinear transformation to produce an estimate of spiking probability. The low-dimensional subspace is estimated using principal components analysis, which gives the neuron’s electrical receptive field (ERF), i.e. the electrodes to which the neuron is most sensitive. Our model suggests that stimulation proportional to the ERF yields a higher efficacy given a fixed amount of power when compared to equal amplitude stimulation on up to three electrodes. We find that the model captures the responses of all the cells recorded in the study, suggesting that it will generalize to most cell types in the retina. The model is computationally efficient to evaluate and, therefore, appropriate for future real-time applications including stimulation strategies that make use of recorded neural activity to improve the stimulation strategy.     

Development of a Threshold Model to Predict Germination of Populus tomentosa Seeds after Harvest and Storage under Ambient Condition

Effects of temperature, storage time and their combination on germination of aspen (Populus tomentosa) seeds were investigated. Aspen seeds were germinated at 5 to 30°C at 5°C intervals after storage for a period of time under 28°C and 75% relative humidity. The effect of temperature on aspen seed germination could not be effectively described by the thermal time (TT) model, which underestimated the germination rate at 5°C and poorly predicted the time courses of germination at 10, 20, 25 and 30°C. A modified TT model (MTT) which assumed a two-phased linear relationship between germination rate and temperature was more accurate in predicting the germination rate and percentage and had a higher likelihood of being correct than the TT model. The maximum lifetime threshold (MLT) model accurately described the effect of storage time on seed germination across all the germination temperatures. An aging thermal time (ATT) model combining both the TT and MLT models was developed to describe the effect of both temperature and storage time on seed germination. When the ATT model was applied to germination data across all the temperatures and storage times, it produced a relatively poor fit. Adjusting the ATT model to separately fit germination data at low and high temperatures in the suboptimal range increased the models accuracy for predicting seed germination. Both the MLT and ATT models indicate that germination of aspen seeds have distinct physiological responses to temperature within a suboptimal range.     

The Long-term Effects of Disturbance on Organic and Inorganic Nitrogen Export in the White Mountains, New Hampshire

Traditional biogeochemical theories suggest that ecosystem nitrogen retention is controlled by biotic N limitation, that stream N losses should increase with successional age, and that increasing N deposition will accelerate this process. These theories ignore the role of dissolved organic nitrogen (DON) as a mechanism of N loss. We examined patterns of organic and inorganic N export from sets of old-growth and historically (80–110 years ago) logged and burned watersheds in the northeastern US, a region of moderate, elevated N deposition. Stream nitrate concentrations were strongly seasonal, and mean (± SD) nitrate export from old-growth watersheds (1.4 ± 0.6 kg N ha⁻¹ y⁻¹) was four times greater than from disturbed watersheds (0.3 ± 0.3 kg N ha⁻¹ y⁻¹), suggesting that biotic control over nitrate loss can persist for a century. DON loss averaged 0.7 (± 0.2) kg N ha⁻¹ y⁻¹ and accounted for 28–87% of total dissolved N (TDN) export. DON concentrations did not vary seasonally or with successional status, but correlated with dissolved organic carbon (DOC), which varied inversely with hardwood forest cover. The patterns of DON loss did not follow expected differences in biotic N demand but instead were consistent with expected differences in DOC production and sorption. Despite decades of moderate N deposition, TDN export was low, and even old-growth forests retained at least 65% of N inputs. The reasons for this high N retention are unclear: if due to a large capacity for N storage or biological removal, N saturation may require several decades to occur; if due to interannual climate variability, large losses of nitrate may occur much sooner. Received 27 April 1999; accepted 30 May 2000.     

Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen

High grazing intensity and wide-spread woody encroachment may strongly alter soil carbon (C) and nitrogen (N) pools. However, the direction and quantity of these changes have rarely been quantified in East African savanna ecosystem. As shifts in soil C and N pools might further potentially influence climate change mitigation, we quantified and compared soil organic carbon (SOC) and total soil nitrogen (TSN) content in enclosures and communal grazing lands across varying woody cover i.e. woody encroachment levels. Estimated mean SOC and TSN stocks at 0–40 cm depth varied across grazing regimes and among woody encroachment levels. The open grazing land at the heavily encroached site on sandy loam soil contained the least SOC (30 ± 2.1 Mg ha^-1) and TSN (5 ± 0.57 Mg ha^-1) while the enclosure at the least encroached site on sandy clay soil had the greatest mean SOC (81.0 ± 10.6 Mg ha^-1) and TSN (9.2 ± 1.48 Mg ha^-1). Soil OC and TSN did not differ with grazing exclusion at heavily encroached sites, but were twice as high inside enclosure compared to open grazing soils at low encroached sites. Mean SOC and TSN in soils of 0–20 cm depth were up to 120% higher than that of the 21–40 cm soil layer. Soil OC was positively related to TSN, cation exchange capacity (CEC), but negatively related to sand content. Our results show that soil OC and TSN stocks are affected by grazing, but the magnitude is largely influenced by woody encroachment and soil texture. We suggest that improving the herbaceous layer cover through a reduction in grazing and woody encroachment restriction are the key strategies for reducing SOC and TSN losses and, hence, for climate change mitigation in semi-arid rangelands.     

Studies on the Tempo of Bubble Formation in Recently Cavitated Vessels: A Model to Predict the Pressure of Air Bubbles

A cavitation event in a vessel replaces water with a mixture of water vapor and air. A quantitative theory is presented to argue that the tempo of filling of vessels with air has two phases: a fast process that extracts air from stem tissue adjacent to the cavitated vessels (less than 10 s) and a slow phase that extracts air from the atmosphere outside the stem (more than 10 h). A model was designed to estimate how water tension (T) near recently cavitated vessels causes bubbles in embolized vessels to expand or contract as T increases or decreases, respectively. The model also predicts that the hydraulic conductivity of a stem will increase as bubbles collapse. The pressure of air bubbles trapped in vessels of a stem can be predicted from the model based on fitting curves of hydraulic conductivity versus T. The model was validated using data from six stem segments each of Acer mono and the clonal hybrid Populus 84K (Populus alba × Populus glandulosa). The model was fitted to results with root mean square error less than 3%. The model provided new insight into the study of embolism formation in stem tissue and helped quantify the bubble pressure immediately after the fast process referred to above.Vulnerability curves (VCs) have been viewed as a good measure of the drought resistance of woody stems (Cochard et al., 2013). Increasing drought increases the xylem tension (T) and eventually induces cavitation of the water in conduits when the T exceeds a certain threshold (Sperry and Tyree, 1988; Sperry et al., 1996). A cavitated vessel first fills with water vapor and eventually fills with air at atmospheric pressure because of Henry’s law, which describes gas equilibrium at the water/air interface. The time required for the progress mainly depends on the penetration rate of air into the recently cavitated vessel lumen via diffusion through the liquid phase.Previous studies were made about how fast bubbles disappear in embolized stems because of the solubility of air in water when water pressure exceeds atmospheric pressure, and the process takes 10 to 100 h depending on conditions (Tyree and Yang, 1992; Yang and Tyree, 1992). The tempo of bubble disappearance was measured by following the rise in stem hydraulic conductivity (k_h) versus time. The theory of Yang and Tyree (1992) relied on the same principles used in this article (Henry’s law, Fick’s law, and the ideal gas law), but modeling and experiments were done at pressures between 1 and 3 times atmospheric pressure rather than subatmospheric pressure (negative pressure). However, much less is known about the tempo of bubble formation in recently cavitated vessels (Brodersen et al., 2013). If the progress of embolus formation takes several minutes, then no changes in conductivity could be observed with available techniques, but if it takes hours, then the tempo of bubbles can be studied by rapidly inducing cavitation with increasing T and after cavitation induction measuring the influence of T on stem k_h as T is reduced gradually to zero. If air bubbles are at a pressure (bubble pressure [P_b*]) lower than a threshold near atmospheric pressure, bubbles ought to collapse when T decreases according to the ideal gas law and Henry’s law (see theory below). The consequence of bubble collapse will be partial filling of vessels with water and the rest with air bubbles. The partial filling of water in a recently cavitated vessel ought to increase the lumen conductivity from zero and connect the embolized vessel to adjacent conductive vessels and, hence, ought to increase the conductivity of the stem by an additional flow pathway (Wheeler et al., 2005; Hacke et al., 2006). The vascular system of stems is a complicated network with vessels of different lengths, diameters, and orientation (Evert, 2006), and the complex vessel network makes the additional pathway possible. Therefore, bubble collapse could be detected through the impact of T on the k_h of the stems in a way that is very similar to the methods used by Yang and Tyree (1992) but requires a more sophisticated centrifuge technique to induce embolism.Many studies have assumed that the bubble pressure in newly cavitated vessels ought to be near atmospheric pressure, and no corrections for bubble pressure have been taken in measuring percentage loss of conductivity (PLC) when T is lower than a critical threshold (Li et al., 2008; Wang et al., 2014a). As a result of bubble collapse, the measured k_h under a mild T should be higher than that under high T (greater than 0.5 MPa). And the lower the initial bubble pressure, the more bubbles collapse with decreasing T.The aim of this study is to construct a model that estimates average bubble pressure in partly embolized stems from the functional dependence of k_h on T, and with this model, we can further our understanding of the tempo of bubble formation in stems. Here, we will argue that the tempo of bubble formation is in two phases: an initial rapid phase (seconds to minutes to complete) followed by a much slower phase (many hours to complete). Since there is no method for measuring the rapid phase, the rapid phase will be described theoretically below. Next, a theory will be developed that allows the estimation of the pressure of air in recently formed bubbles in vessels during the slow phase. An experimental validation of the model will follow that will yield values of bubble pressure within the first 1 to 2 h following the fast phase of embolism formation in vessels.     

A New Conceptual Model of Nitrogen Saturation Based on Experimental Nitrogen Addition to an Oak Forest

The dominant conceptual model of nitrogen (N) saturation in forests predicts the temporal patterns of key N cycling indicators as an initially N-limited forest is progressively enriched in N. We present the results from a long-term N addition experiment in an oak forest in southeastern New York State, USA, which do not conform to the predictions of the conceptual model in several ways. In contrast to the predictions of the conceptual model, the foliar N concentrations in the N-treated stands of our study increased to about 20% above the levels in the control stands and then remained essentially constant, and nitrogen leaching from the treated stands increased almost immediately after the start of the experiment, prior to the onset of elevated nitrification. Concentrations of N in soil solution of the N-treated stands peaked at over 150-fold greater than the concentrations in the control stands. There were no significant changes in potential net N mineralization. Tree mortality increased in the treated stands, but the tree mortality did not appear to be the primary cause of the excess nitrate leaching. Based on these results and those of other recent studies, we present a new conceptual model of the N saturation process focused on the mass balance of N rather than the temporal dynamics of N cycling indicators. The mass balance is characterized by inputs of N from atmospheric deposition and fertilization, internal sinks in the vegetation and soils, and outputs to leaching and gaseous losses. The key points of the conceptual model are (1) added N can flow simultaneously to all sinks and losses in the system, (2) the fate of the added N and the temporal patterns of flow of N depend on the strength of the sinks and the factors that control them, and (3) the movement of N to the various sinks determines how N saturation is manifested in the ecosystem. We distinguish capacity N saturation, in which the sinks in the vegetation and soil are zero or negative, from kinetic N saturation, in which the sinks are positive but lower than the N input rate. The sink strengths in the vegetation and soil have two components, one due to carbon (C) accumulation in the system and the other due to change in the stoichiometry (C:N ratio) of the pool. Further work quantifying the magnitudes and controlling factors for the N sinks will allow better prediction of the dynamics of N saturation in different types of forested ecosystems.     

A Prognostic Model to Predict Recovery of COVID-19 Patients Based on Longitudinal Laboratory Findings

Virologica Sinica - The temporal change patterns of laboratory data may provide insightful clues into the whole course of COVID-19. This study aimed to evaluate longitudinal change patterns of key...     

Proliferation Index: A Continuous Model to Predict Prognosis in Patients with Tumours of the Ewing's Sarcoma Family

The prognostic value of proliferation index (PI) and apoptotic index (AI), caspase-8, -9 and -10 expression have been investigated in primary Ewing''s sarcoma family of tumours (ESFT). Proliferating cells, detected by immunohistochemistry for Ki-67, were identified in 91% (91/100) of tumours with a median PI of 14 (range 0–87). Apoptotic cells, identified using the TUNEL assay, were detected in 96% (76/79) of ESFT; the median AI was 3 (range 0–33). Caspase-8 protein expression was negative (0) in 14% (11/79), low (1) in 33% (26/79), medium (2) in 38% (30/79) and high (3) in 15% (12/79) of tumours, caspase-9 expression was low (1) in 66% (39/59) and high (3) in 34% (20/59), and caspase-10 protein was low (1) in 37% (23/62) and negative (0) in 63% (39/62) of primary ESFT. There was no apparent relationship between caspase-8, -9 and -10 expression, PI and AI.PI was predictive of relapse-free survival (RFS; p = 0.011) and overall survival (OS; p = <0.001) in a continuous model, whereas AI did not predict outcome. Patients with tumours expressing low levels of caspase-9 protein had a trend towards a worse RFS than patients with tumours expressing higher levels of caspase-9 protein (p = 0.054, log rank test), although expression of caspases-8, -9 and/or -10 did not significantly predict RFS or OS. In a multivariate analysis model that included tumour site, tumour volume, the presence of metastatic disease at diagnosis, PI and AI, PI independently predicts OS (p = 0.003). Consistent with previous publications, patients with pelvic tumours had a significantly worse OS than patients with tumours at other sites (p = 0.028); patients with a pelvic tumour and a PI≥20 had a 6 fold-increased risk of death. These studies advocate the evaluation of PI in a risk model of outcome for patients with ESFT.     

Effects of Nitrogen Deposition on the Abundance and Metabolism of Lichens: A Meta-analysis

Ecosystems - Lichens are the key to nutrient cycling and trophic networks in many terrestrial ecosystems and are good bioindicators of air pollution, including nitrogen (N) deposition. Experimental...     

Nitrogen loading from watersheds to estuaries: Verification of the Waquoit Bay Nitrogen Loading Model

World-wide eutrophication of estuaries has made accurate estimation ofland-derived nitrogen loads an important priority. In this paper we verifypredictions of nitrogen loads made by the Waquoit Bay Nitrogen LoadingModel (NLM). NLM is appropriate for watersheds with mixes of forested,agricultural, and residential land uses, and underlain by coarseunconsolidated sediments. NLM tracks the fate of nitrogen inputs byatmospheric deposition, fertilizer use, and wastewater disposal, and assignslosses of nitrogen from each source as the nitrogen is transported throughthe land use mosaic on the watershed surface, then through the underlyingsoils, vadose zones, and aquifers.We verified predictions of nitrogen loads by NLM in two independent ways.First, we compared NLM predictions to measured nitrogen loads in differentsubestuaries in the Waquoit Bay estuarine system. Nitrogen loads predictedby NLM were statistically indistinguishable from field-measured nitrogenloading rates. The fit of model predictions to measurements remained goodacross the wide range of nitrogen loads, and across a broad range in size(10–10,000 ha) of land parcels. NLM predictions were most precise whenspecific parcels were larger than 200 ha, and within factors of 2 for smallerparcels.Second, we used NLM to predict the percentage of nitrogen loads toestuaries contributed by wastewater, and compared this prediction to the¹⁵N signature distinguishable from N derived fromatmospheric or fertilizer sources. The greater the contribution ofwastewater, the heavier the ¹⁵N value in groundwater. Thesignificant linear relation between NLM predictions of percent wastewatercontributions and stable isotopic signature corroborated the conclusionthat model outputs provide a good match to empirical measurements. Thegood agreement obtained in both verification exercises suggests that NLMis an useful tool to address basic and applied questions about how land usepatterns alter the fate of nitrogen traversing land ecosystems, and thatNLM provides verified estimates of the land-derived nitrogen exports thattransform receiving aquatic ecosystems.     

Effects of Dietary Selenium Source,Storage Time,and Temperature on the Quality of Quail Eggs

We report the effects of time of storage, temperature, and supplementation with sodium selenite- and selenium-enriched yeast on the quality of quail eggs. For this study, 90 10-week-old female Japanese quails (Coturnix coturnix japonica) with similar body size were caged individually and randomly divided into five groups of 18 quails each. One group was fed a normal diet and served as control. A second group was supplemented with 0.2 mg/kg sodium selenite (In-Se) and three groups supplemented with 0.1, 0.2, and 0.3 mg/kg of a commercially available selenium-enriched yeast (O-Se1, O-Se2, and O-Se3, respectively). The eggs were collected at third and fourth weeks of the experiment and were stored at 4°C and 20°C for 0, 15, 30, and 45 days. Extension of the storage time to 45 days at 20°C resulted in significant deterioration of egg quality. The albumen Haugh unit (HU), pH, albumen index, yolk index, and egg weight loss were the most important parameters influenced by the nature of the selenium sources, storage time, and temperature. Storage time and temperature were also significant for egg weight loss, HU, and albumen and yolk indexes. The results show that supplementation with selenium yeast significantly affected shell weight, shell thickness, HU, albumen index, yolk index, and pH. The HU decreased with increased storage time and temperature. Higher levels of Se-yeast administration resulted in greater HU compared to the selenite and control groups.     

Development of a Model to Predict the Effect of Temperature and Moisture on Fungal Spore Longevity

A model was developed to quantify the effect of temperatureand moisture content on the longevity of conidia of the entomopathogenicfungusMetarhizium flavoviride . This model incorporated a negativesemi-logarithmic relation between longevity and temperatureand a negative logarithmic relation between longevity and moisturecontent. Replacing the latter with a negative semi-logarithmicrelation between longevity and the equilibrium relative humidityof the conidia was also effective. The latter model was appliedsuccessfully to observations on the survival of conidia of afurther four entomopathogenic fungi (Metarhizium anisopliae,Beauveria bassiana ,Beauveria brongniartii, andPaecilomycesfarinosus ) and ascospores, conidia or uredospores of four phytopathogenicfungi (Alternaria porri ,Helminthosporium oryzae ,Uromyces appendiculatus, andSclerotinia sclerotiorum ) across a wide range of differenttemperatures and relative humidities. The sensitivity of sporelongevity to both temperature and equilibrium relative humidity,and the upper and lower relative humidity limits to the applicationof the model, varied considerably between entomopathogenic andphytopathogenic fungi, among species within each group, andamong different strains within certain species. Metarhizium flavoviride W. Gams & J. Roszypal; entomopathogenic fungi; phytopathogenic fungi; spore survival; storage environment; conidia; uredospore; ascospore