Habitat degradation,topography and rainfall variability interact to determine seed distribution and recruitment in a sand dune grassland

Question: Understanding the mechanisms underlying how habitat degradation, topography and rainfall variability interactively affect seed distribution and seedling recruitment is crucial for explaining plant community patterns and dynamics. Interactions between these major factors were studied together in a semiarid sand dune grassland. Location: Eastern Inner Mongolia, China. Methods: The study system used four sites of fixed, semifixed, semishifting and shifting sand dune grasslands, representing a gradient of habitat degradation. We investigated the density of germinable seeds deposited in the top 5 cm of soil and in situ seedling emergence (number of seedlings emerging early in the growing season) and establishment (number of plants recruited at the end of the growing season) at three topographic positions (dune top, windward and leeward sides) within each site over 2 years that differed in rainfall. Habitat characteristics (i.e. vegetation cover, plant species composition and diversity, soil moisture and nutrient availability and soil erodibility) of the four sites were also measured. Results: Habitat degradation (i.e. decreased vegetation cover and enhanced wind erosion rate) significantly reduced the size of the germinable soil seed bank. On average, germinable seed number from the high‐vegetation cover fixed dune was 36‐fold larger than the low‐vegetation cover shifting dune, and eight‐ and two‐fold larger, respectively, than the semishifting and semifixed dunes with intermediate vegetation cover. We observed within‐habitat variability in seed distribution, but among‐topographic position variation differed among habitats. Seedling recruitment showed large between‐year, and among‐ and within‐habitat variability, but these variations varied significantly depending on the response variables evaluated (i.e. initial seedling density, final plant density, emergence rate and recruitment rate). Path analysis revealed complex density‐dependent positive and negative, direct and indirect effects of germinable seed density and initial seedling density on recruitment, but the relative importance of these density‐dependent effects varied depending on habitat type and rainfall availability. Conclusion: Our results suggest that habitat degradation, microtopography and rainfall availability interact in shaping sand dune seed bank and plant community recruitment patterns and dynamics. Their effects were mainly mediated through changes in both the biotic and abiotic environment during the process of habitat deterioration.     

Interactive effects between plant functional types and soil factors on tundra species diversity and community composition

Plant communities are coupled with abiotic factors, as species diversity and community composition both respond to and influence climate and soil characteristics. Interactions between vegetation and abiotic factors depend on plant functional types (PFT) as different growth forms will have differential responses to and effects on site characteristics. However, despite the importance of different PFT for community assembly and ecosystem functioning, research has mainly focused on vascular plants. Here, we established a set of observational plots in two contrasting habitats in northeastern Siberia in order to assess the relationship between species diversity and community composition with soil variables, as well as the relationship between vegetation cover and species diversity for two PFT (nonvascular and vascular). We found that nonvascular species diversity decreased with soil acidity and moisture and, to a lesser extent, with soil temperature and active layer thickness. In contrast, no such correlation was found for vascular species diversity. Differences in community composition were found mainly along soil acidity and moisture gradients. However, the proportion of variation in composition explained by the measured soil variables was much lower for nonvascular than for vascular species when considering the PFT separately. We also found different relationships between vegetation cover and species diversity according the PFT and habitat. In support of niche differentiation theory, species diversity and community composition were related to edaphic factors. The distinct relationships found for nonvascular and vascular species suggest the importance of considering multiple PFT when assessing species diversity and composition and their interaction with edaphic factors. Synthesis: Identifying vegetation responses to edaphic factors is a first step toward a better understanding of vegetation–soil feedbacks under climate change. Our results suggest that incorporating differential responses of PFT is important for predicting vegetation shifts, primary productivity, and in turn, ecosystem functioning in a changing climate.     

Assessing the sensitivity of Melanoplus frigidus (Orthoptera: Acrididae) to different weather conditions: A modeling approach focussing on development times

The temperature and soil moisture conditions as well as vegetation patterns were studied to describe the habitat and to model the life cycle of Melanoplus frigidus, a true alpine grasshopper of the Scandes. In the low alpine belt of the Norwegian Scandes the species colonizes only the warmest microhabitats with maximum soil surface temperatures of 31°C. Vegetation of these habitats consists of shrub‐rich heath dominated by Vaccinium myrtillus and Calluna vulgaris. Using continuously measured temperature data, the development times for four different seasons were modeled and related to field observations. The maximum delay of adult molt was estimated to amount to 3 weeks, the delay being determined by the variation in spring temperature conditions between different years. The possibilities of using M. frigidus as an indicator organism of climate change effects on alpine zoo‐coenoses of the Scandes are discussed.     

Vegetation maps based on remote sensing are informative predictors of habitat selection of grassland birds across a wetness gradient

Vegetation is a major environmental factor influencing habitat selection in bird species. High resolution mapping of vegetation cover is essential to model the distribution of populations and improve the management of breeding habitats. However, the task is challenging for grassland birds because microhabitat variations relevant at the territory scale cannot be measured continuously over large areas to delineate areas of higher suitability. Remote sensing may help to circumvent this problem. We addressed this issue by using SPOT 5 imagery and phytosociological data. We mapped grassland vegetation in a floodplain using two methods. We (i) mapped the continuous Ellenberg index of moisture and (ii) identified 5 vegetation classes distributed across the wetness gradient. These two methods produced consistent output maps, but they also provided complementary results. Ellenberg index is a valuable proxy for soil moisture while the class approach provided more information about vegetation structure, and possibly trophic resources. In spite of the apparent uniformity of meadows, our data show that birds do not settle randomly along the moisture and vegetation gradients. Overall birds tend to avoid the driest vegetation classes, i.e. the highest grounds. Thus, vegetation maps based on remote sensing could be valuable tools to study habitat selection and niche partition in grassland bird communities. It is also a valuable tool for conservation and habitat management.     

Long‐term productivity of Mediterranean herbaceous vegetation after a single phosphorus application

Question: What is the mechanism that underlies long‐term maintenance of high herbaceous productivity after a single application of phosphorus (4.5 gP m^?2 and 9 gP m^?2) in a hilly Mediterranean environment in a phosphorus‐deficient ecosystem? Location: Inland, 15 km E of the Mediterranean coast, W Galilee, Israel (35°15′E, 33°01′N; 500 m asl). Methods: The experiment was established in 1988. Multi‐year data on above‐ground biomass, botanical composition, P content of vegetation and soil, and the grazing management context of the experiment were integrated to construct a feasible account of the P dynamics of the ecosystem. Results: The productivity of the herbaceous component already responded to P application in the first year. The effect on the shrubby component of the ecosystem was marginal. The available (bicarbonate extractable) P in the upper soil layer peaked in the year after application of P and then declined to the original level within 7 years. Despite the decline in available soil P, a high, fluctuating level of herbaceous biomass production was maintained for 20 years. Legume species (Fabaceae) became a prominent constituent of the herbaceous vegetation after the P pulse. Conclusions: The long‐term shift in productivity of the herbaceous component of the grazed ecosystem was triggered by a nutritional pulse that induced a feedback loop based on changes in botanical composition of the herbaceous vegetation, the animal–vegetation interaction, grazing and supplementary feeding regimen of the cattle.     

Ecosystem engineering by foxes is mediated by the landscape context—A case study from steppic burial mounds

In intensively used landscapes, remnant grassland fragments are often restricted to places unsuitable for agricultural cultivation. Such refuges are the ancient burial mounds called “kurgans,” which are typical landscape elements of the Eurasian steppe and forest steppe zone. Due to their hill‐like shape, loose soil structure and undisturbed status kurgans provide proper habitats for burrowing mammals. Accordingly, grassland vegetation on kurgans is often exposed to bioturbation, which can influence the habitat structure and plant species pool. In our study, we explored the effect of fox burrows and landscape context on the habitat properties and vegetation composition of small landscape elements, using kurgans as model habitats. We surveyed the vegetation of fox burrows and that of the surrounding grassland on five kurgans situated in cleared landscapes surrounded by arable lands and five kurgans in complex landscapes surrounded by grazed grasslands. We recorded the percentage cover of vascular plants, the amount of litter, and soil moisture content in twelve 0.5 m × 0.5 m plots per kurgan, in a total of 120 plots. We found that foxes considerably transformed habitat conditions and created microhabitats by changing the soil nutrient availability and reducing total vegetation cover and litter. Several grassland specialist species, mostly grasses (Agropyron cristatum, Elymus hispidus, and Stipa capillata) established in the newly created microhabitats, although the cover of noxious species was also considerable. We found that landscape context influenced the sort of species which could establish on kurgans by affecting the available species pool and soil moisture. Our results revealed that foxes act as ecosystem engineers on kurgans by transforming abiotic and biotic conditions by burrowing. Their engineering activity maintains disturbance‐dependent components of dry grasslands and increases local environmental heterogeneity.     

Effect of habitat type and soil moisture on pupal stage of a Mediterranean forest pest (Thaumetopoea pityocampa)

相似文献   

重庆主城河岸带植物群落功能性状与土壤理化性质的关系

基于功能性状视角开展植物群落与环境关系的研究有助于揭示植物的适应策略。然而,目前关于城市河岸带植物群落功能性状的研究较少。为此选取10项植物功能性状指标和14项土壤理化性质指标,探究重庆主城3种生境类型河岸带(自然型河岸带(NRZ)、农耕主导型河岸带(FRZ)和开发建设主导型河岸带(BRZ))植物群落功能性状与土壤因子特征及互作机制。结果表明：(1)与NRZ生境相比,FRZ生境中的土壤速效磷、速效钾和氧化还原电位和BRZ生境中的土壤含水量显著偏高(P<0.05);FRZ和BRZ生境中的土壤pH值和全磷含量显著偏高,而土壤有机质、全钾和全氮含量显著偏低(P<0.05)。(2)与NRZ生境相比,FRZ生境中的比根长和比根表面积显著较高,茎干物质含量和叶干物质含量显著较低;BRZ生境中仅茎干物质含量显著较低(P<0.05)。(3)冗余分析结果表明,影响各生境类型河岸带植物群落功能性状的土壤因子不同,NRZ生境为土壤容重、含水量和硝态氮,FRZ生境为土壤铵态氮、全磷和有机质,BRZ生境则是土壤含水量、温度和速效磷。研究发现与自然状态相比,农业和建筑类型的人为干扰导致重庆主城河...     

Diversity of pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) in eastern Thailand

Pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) are cosmopolitan, species‐rich, and yet poorly studied, particularly in the tropics. We sampled beetles in three types of primary forest and two types of disturbed forest habitats in eastern Thailand to assess the utility of pselaphine beetles as bioindicators of forest disturbance. We simultaneously measured leaf litter mass, soil moisture, soil acidity and canopy cover at each site to infer which environmental factors affect pselaphine beetle diversity and abundance. At each site, pselaphine beetles were extracted from ten 1 m² samples of leaf litter and soil with Tullgren funnels. We sampled 1867 adult beetles representing six supertribes, 51 genera and 114 morphospecies; 7% of the genera and 92% of the species were undescribed. Forest types differed significantly in species richness, abundance, diversity and evenness. Primary forest had greater numbers of species and individuals, and higher diversity indices (H′). Teak plantation and secondary forest had substantially fewer individuals and species of pselaphine beetles. Species composition differed between primary and degraded forests. Canopy cover, soil moisture, and leaf litter mass positively correlated with beetle species richness and abundance. Leaf litter mass and soil moisture were the two most important factors affecting the diversity of pselaphine beetle assemblages. Among the 114 morphospecies collected, 43 morphospecies were specific to two or three habitats and 64 morphospecies were found only in a single habitat. Thus pselaphine beetles appear to have rather narrow habitat requirements and their presence/absence was correlated with environmental differences. These traits make pselaphine beetles a suitable bioindicator taxon for assessing forest litter diversity and monitoring habitat change.     

Soil moisture's underestimated role in climate change impact modelling in low‐energy systems

Shifts in precipitation regimes are an inherent component of climate change, but in low‐energy systems are often assumed to be less important than changes in temperature. Because soil moisture is the hydrological variable most proximally linked to plant performance during the growing season in arctic‐alpine habitats, it may offer the most useful perspective on the influence of changes in precipitation on vegetation. Here we quantify the influence of soil moisture for multiple vegetation properties at fine spatial scales, to determine the potential importance of soil moisture under changing climatic conditions. A fine‐scale data set, comprising vascular species cover and field‐quantified ecologically relevant environmental parameters, was analysed to determine the influence of soil moisture relative to other key abiotic predictors. Soil moisture was strongly related to community composition, species richness and the occurrence patterns of individual species, having a similar or greater influence than soil temperature, pH and solar radiation. Soil moisture varied considerably over short distances, and this fine‐scale heterogeneity may contribute to offsetting the ecological impacts of changes in precipitation for species not limited to extreme soil moisture conditions. In conclusion, soil moisture is a key driver of vegetation properties, both at the species and community level, even in this low‐energy system. Soil moisture conditions represent an important mechanism through which changing climatic conditions impact vegetation, and advancing our predictive capability will therefore require a better understanding of how soil moisture mediates the effects of climate change on biota.     

Formulation development of the biocontrol agent Bacillus subtilis strain CPA-8 by spray-drying

Aims: To prepare commercially acceptable formulations of Bacillus subtilis CPA‐8 by spray‐drying with long storage life and retained efficacy to control peach and nectarine brown rot caused by Monilinia spp. Methods and Results: CPA‐8 24‐h‐ and 72‐h‐old cultures were spray dried using 10% skimmed milk, 10% skimmed milk plus 10% MgSO₄, 10% MgSO₄ and 20% MgSO₄ as carriers/protectants. All carriers/protectants gave good percentages of powder recovery (28–38%) and moisture content (7–13%). CPA‐8 survival varied considerably among spray‐dried 24‐h‐ and 72‐h‐old cultures. Seventy‐two hours culture spray dried formulations showed the highest survival (28–32%) with final concentration products of 1·6–3·3 × 10⁹ CFU g^?1, while viability of 24‐h‐old formulations was lower than 1%. Spray‐dried 72‐h‐old formulations were selected to subsequent evaluation. Rehydration of cells with water provided a good recovery of CPA‐8 dried cells, similar to other complex rehydration media tested. Spray‐dried formulations stored at 4 ± 1 and 20 ± 1°C showed good shelf life during 6 months, and viability was maintained or slightly decreased by 0·2–0·3‐log. CPA‐8 formulations after 4‐ and 6 months storage were effective in controlling brown rot caused by Monilinia spp. on nectarines and peaches resulting in a 90–100% reduction in disease incidence. Conclusions: Stable and effective formulations of biocontrol agent B. subtilis CPA‐8 could be obtained by spray‐drying. Significance and Impact of the Study: New shelf‐stable and effective formulations of a biocontrol agent have been obtained by spray‐drying to control brown rot on peach.     

阿尔金山保护区藏野驴和野牦牛夏季生境选择分析

本研究在2012至2013年进行两次调查,采用样带法和样方法在阿尔金山自然保护区东部(37°15'~37°23'N,90°11'~90°20'E)对藏野驴(Equus kiang)、野牦牛(Bos grunniens)的分布及其栖息地进行调查,共设置3条样线(总长达146.9 km)和128个样方。调查发现,藏野驴主要集中于伊协克帕提附近的荒漠草原,而野牦牛的主要栖息地位于沙山附近的阿坝堤坝草场。通过Vanderloeg和Scavia选择系数以及主成分分析,对藏野驴和野牦牛对不同环境因子(包括植被类型、植被盖度、草本种类数、土壤pH、海拔、坡度、坡向、水源)的选择性以及各因子在物种栖息地选择的重要程度进行研究,同时利用独立T检验分析两物种之间的环境变量选择差异性。结果表明,藏野驴倾向选择植被盖度小于70%,坡度2°~5°的南坡,海拔3800~4000 m,土壤pH 8.0~8.5的高寒荒漠生境;野牦牛则偏好选择植被盖度大于70%,坡度5°~15°的东坡或者北坡,海拔4200~4600 m,土壤pH 7.0~8.0,与水源距离小于1000 m的高寒荒漠草原以及沼泽草甸生境;影响藏野驴生境选择的主要因子为植被类型和坡度,而影响野牦牛生境选择的主要因子是植被盖度;虽然藏野驴和野牦牛在资源利用上存在部分重叠,但它们对栖息地植被盖度、植被高度、海拔和坡度的选择存在显著差异性(P0.05)。     

Gradient analysis of reversed treelines and grasslands of the Valles Caldera,New Mexico

Objective: : Treeless meadows and parks are widespread but poorly understood features of the montane vegetation of the western USA. These communities frequently form reversed treelines where grassy valleys occur below forested slopes above. Our purpose was to assess the environmental correlates of such treelines, as well as patterns in the composition and diversity of grasslands and forest margins in the Valles Caldera National Preserve. Location: Valles Caldera National Preserve (35°50′‐36°00’ N, 106°24′‐106°37’ W, 2175–3150 m), Jemez Mountains, New Mexico, USA. Methods: We conducted a gradient analysis based on 200 nested quadrats on transects crossing reversed treelines and spanning the compositional heterogeneity of grasslands. We used cluster analysis and non‐metric multidimensional scaling to assess relationships between compositional variation and environmental variables. Results: We found strong, highly significant relationships of the vegetation to gradients in slope inclination, soil texture, moisture, nutrient availability, and nighttime minimum temperatures. Reversed treelines are most strongly associated with shifts in the thermal regime, exhibit weaker relationships with soil texture and nutrient content, and show no relationship with gravimetric soil moisture. Gradients in aspect, soil moisture, and annual mean temperature are associated with compositional variation within grasslands and forest margins. Conclusions: Lower nightly minimum temperatures and fewer consecutive frost‐free days resulting from cold‐air drainage may prevent tree seedling establishment in valley bottoms via photo‐inhibition, tissue damage, or frost heaving. Fine‐textured soils may also impede tree seedling establishment in valley bottoms. These findings lay the groundwork for experimental and physiological tests of these potential causes of these reversed treelines.     

Revegetation and its Effect on the Ground-Dwelling Beetle Fauna of Matiu-Somes Island, New Zealand

A study of beetle (Coleoptera) communities was conducted in three revegetated sites of different ages (5, 17, and 100 years) and in a remnant coastal habitat dominated by Muehlenbeckia complexa (a liane) on Matiu‐Somes Island, Wellington Harbor, New Zealand. The 25‐ha island has had a 110‐year history as a pastoral agricultural quarantine station. Beetles were surveyed from May 1997 to April 1998 using pitfall traps. We collected a total of 3,430 adult beetles from 78 beetle species belonging to 22 families. Various environmental factors influencing the distribution of beetles in revegetated habitats were investigated. The most important factors were canopy height and canopy density (functions of vegetation age). Overall, results suggest that as habitat/vegetational heterogeneity increases at a site, beetle diversity and abundance also increase. Thus, older replanted sites contained a greater species richness and abundance of beetles than newly replanted sites. Revegetation is, thus, successfully facilitating the establishment and recolonization of the beetle fauna on Matiu‐Somes Island.     

三峡库区澎溪河消落带植物群落分布格局及生境影响

三峡消落带是一条特殊的水—陆交错带,其生境的特殊性及对整个三峡库区的影响逐渐成为地学、环境科学、生态学等学科的研究热点。植被是消落带各项生态功能的载体。然而,三峡水库的运行使消落带原有植被遭到破坏。通过对澎溪河消落带植物群落及其生境的实地调查,采用双向指示种法(TWINSPAN)划分植物群落类型,并结合方差分解和CCA排序法研究4类生境影响因素组14个生境影响因子与植物群落空间分布的关系,探讨生境对消落带植物群落组成、结构及多样性的影响。结果表明:(1)消落带植物群落包括5种类型:狗牙根+雀稗群落、狗尾草+狗牙根群落、黄荆群落、白茅+鬼针草群落、苔草群落;(2)CCA排序中,第1排序轴对消落带植被空间变化的累计解释量为6.83%,占生境条件总解释量的44.73%,能很好地解释消落带植物群落与生境的相互关系,植物群落类型沿排序轴呈梯度分布;(3)土壤是影响消落带植被空间分布格局的主要影响因素组,各影响因素组间交互作用明显。淹水时间、海拔、土壤含水量是植物群落空间分布的主要影响因子,解释量分别为5.3%、3.0%、2.9%;(4)4类影响因素组共解释消落带植物群落空间格局变化的14.6%,未解释部分所占比例较大,可能是由于消落带内生境条件复杂,影响其群落组成及空间分布的潜在因素较多,如各种土地利用政策、人类活动干扰及景观组成等因素也可能对消落带植物群落构成有影响。研究消落带植物空间分布及其与生境的关系,以期为科学认识消落带、保护水库环境提供依据。     

Artificial Spawning Habitats Improve Egg Production of a Declining Diadromous Fish,Galaxias maculatus (Jenyns, 1842)

Anthropogenic impacts from urbanization, deforestation, and agriculture have degraded the riparian margins of waterways worldwide. In New Zealand, such impacts have caused changes in native vegetation, enhanced invasion by exotic grasses, and altered river bank morphology. One consequence has been a great reduction in obligate spawning habitat of a diadromous fish, Galaxias maculatus. Juvenile G. maculatus comprise a culturally important fishery that has been considerably reduced over recent decades. Rehabilitation of riparian vegetation needed for spawning is relatively straightforward, but slow. We hypothesized that artificial spawning habitats could accelerate restoration of fish egg production by creating an environment that would support at least the same density and survival of eggs as non‐impacted vegetation. We tested three artificial devices (straw bales, straw tubes, and moss tubes) in degraded and intact sites. Eggs were laid in all of these with numbers and survival usually exceeding that in riparian grasses. Where habitat was degraded, artificial spawning habitats yielded up to 10,000 eggs compared to none in nearby natural spawning habitat. The ground‐level environment of artificial habitat was similar to that of intact vegetation in buffering ambient temperature and humidity fluctuations. Crucial properties of the artificial habitats were (1) shelter to provide shade and hold moisture; (2) accessibility to allow adult fish to deposit and fertilize eggs; and (3) robustness to provide reliable surfaces and protection for the eggs during their development. We show that artificial spawning habitats are a viable short‐term alternative to rehabilitating spawning habitat while legacy effects abate and riparian vegetation recovers.     

Linking the spatio‐temporal distribution of an edaphic crane fly to its heterogeneous soil environment

相似文献   

Changes in microclimate induced by experimental warming and clipping in tallgrass prairie

In order to facilitate interpretation and comparison of warming effects on ecosystems across various habitats, it is imperative to quantify changes in microclimate induced by warming facilities. This paper reports observed changes in air temperature, soil temperature and soil‐moisture content under experimental warming and clipping in a tallgrass prairie in the Great Plains, USA. We used a factorial design with warming as the primary factor nested with clipping as the secondary factor. Infrared heater was used in order to simulate climatic warming and clipping to mimic mowing for hay or grazing. The warming treatment significantly increased daily mean and minimum air temperatures by 1.1 and 2.3 °C, respectively, but had no effect on daily maximum air temperature, resulting in reduced diurnal air‐temperature range. Infrared heaters substantially increased daily maximum (2.5 and 3.5 °C), mean (2.0 and 2.6 °C) and minimum (1.8 and 2.1 °C) soil temperatures in both the unclipped and clipped subplots. Clipping also significantly increased daily maximum (3.4 and 4.3 °C) and mean (0.6 and 1.2 °C) soil temperatures, but decreased daily minimum soil temperature (1.0 and 0.6 °C in the control and warmed plots, respectively). Daily maximum, mean and minimum soil temperatures in the clipped, warmed subplots were 6.8, 3.2 and 1.1 °C higher than those in the unclipped, control subplots. Infrared heaters caused a reduction of 11.0% in soil moisture in the clipped subplots, but not in the unclipped subplots. Clipping reduced soil‐moisture content by 17.7 and 22.7% in the control and warmed plots, respectively. Experimental warming and clipping interacted to exacerbate soil‐moisture loss (26.7%). Overall, infrared heaters simulated climate warming well by enhancing downward infrared radiation and by reducing the diurnal air‐temperature range.     

Release behavior of allyl sulfide from cyclodextrin inclusion complex of allyl sulfide under different storage conditions

The stability of allyl sulfide, an organosulfur compound present in garlic oil, in its α-, β-, and γ-cyclodextrin inclusion complexes was investigated under various storage conditions. The complexes of cyclodextrins and allyl sulfide were prepared by spray drying. The storage temperature, relative humidity, and initial moisture content of the inclusion complex had different effects on the release rate of allyl sulfide. Allyl sulfide in α-cyclodextrin complexes had a lower release rate than in β- and γ-cyclodextrin complexes at 100 °C and at 50 °C under 6, 40, 54, and 73% relative humidity. The initial moisture content affected only the release rate of allyl sulfide from α-cyclodextrin complexes. The release behavior of allyl sulfide can be correlated with the first-order release rate equation with a normal Gaussian distribution of free energy of activation of release rate constant. The results indicated α-cyclodextrin is a suitable material for controlled release of allyl sulfide.