Stages Of Ecosystem Development Research Articles

From Early Curiosity to Space Wide Web: Emergence of the Small Satellite Innovation Ecosystem

Much of the existing literature on ecosystems has focused on established ecosystems, but we know little about how an ecosystem actually emerges and evolves in the first place. We layout four stages of ecosystem development, integrate two critical ecosystem concepts of multilateral interdependence and non-generic complementarity, and delineate a typical trajectory along which multilateral non-generic complementarity develops across the stages. We develop theoretical insights on how the gradual process of multilateral non-generic complementarity development enables materialization of a coherent, customer-centric, economic value proposition in an innovation ecosystem. To illustrate our theoretical framework, we conduct a longitudinal case study of the modern small satellite innovation ecosystem from its inception to now. Our analysis uncovers the dynamic process of how small satellites evolved from a seed innovation with unclear value proposition to become an innovation ecosystem that delivers strong modern space capabilities. Our paper provides deeper insight on ecosystem emergence and evolution and has important implications for ecosystem strategizing by firms both individually and collectively.

Fundamental Cultural studies on the role of humanity in the Ecosystem genesis

The paper formulates the problem of understanding the essence of the Ecosystem and the role that is assigned to humanity as a unique cultural taxon at a certain stage of Ecosystem development. Within the framework of the fundamental culturological approach, it is possible to find an answer to the question “why does a person live?”, which is crucial for applied culturology and the formalization of cultural policy at the present stage of civilization.

Resource orchestration in innovation ecosystems: a comparative study between innovation ecosystems at different stages of development

Objective of the study: The present study aimed to answer the following question: How are resources orchestrated to generate innovation in innovation ecosystems?Methodology/Approach: An exploratory qualitative research was conducted through documentary analysis, non-participant observation, and in-depth interviews with actors from two Brazilian ecosystems in different stages of development: 4th District (emerging) and Porto Digital (growth).Originality/Relevance: Innovation ecosystems can be understood as a set of resources that foster innovation. Current research suggests that even more important than resources is the articulation among them and the way they are orchestrated.Main Results: It was found that resource pooling characterizes the transition moment from the emergency stage to the growth stage.Theoretical/ Methodological Contribution: A direct relationship between resource orchestration and the stage of ecosystem development was identified.Social/Management Contribution: The importance of the orchestration role, as well as the presence of an orchestrating actor, was emphasized, and a framework of analysis on the orchestration of resources in innovation ecosystems was proposed.

A 5200-year paleoecological and geochemical record of coastal environmental changes and shoreline fluctuations in southwestern Louisiana: Implications for coastal sustainability

This study presents a 5200-year history of coastal environmental changes and shoreline fluctuations based on a multi-proxy sedimentary record developed from the eastern end of Louisiana's Chenier Plain. Palynological, loss-on ignition, grain-size, and X-ray fluorescence data for a 525 cm sedimentary core indicate five stages of ecosystem development in the Rockefeller Wildlife Refuge since the mid-Holocene. Between 5190 and 4240 cal yr BP, the relative sea-level was much lower than the present level, and our study area was occupied by a baldcypress swamp. When the Sale-Cypremont subdelta complex formed at a western position approximately 4600 years ago, our study area was transformed to a maritime forest about 4240–3440 cal yr BP, suggesting shoreline progradation. When the Mississippi River delta lobe switched to more easterly positions during the Teche, St. Bernard, Lafourche, and Plaquemine-Balize complexes, our study site was transformed back to a freshwater swamp between 3440 and 1520 cal yr BP and then to a coastal marsh between 1520 and 300 cal yr BP. After the Atchafalaya-Wax Lake subdelta complex formed at a more westerly position again, the modern-day beach form at 300 cal yr BP. These coastal ecosystem developments suggest that shoreline retreat started at ~3440 cal yr BP and persisted to the present day. In addition, evidence of at least four possible paleohurricane events was found during the late Holocene. Our multi-proxy record demonstrates that shoreline fluctuation in southwestern Louisiana was tied to the Mississippi River Delta Switch since the mid-Holocene. Shoreline progradation occurred during the Sale-Cypremont subdelta phase ~5200–3500 years ago, when the sediment supply was high. Retrogradation occurred after ~3500 cal yr BP when the Mississippi River subdelta complexes occupied more easterly position, resulting in diminished sediment supply. A significant increase in the delivery of water and total suspended sediment load from the Atchafalaya River to the Gulf of Mexico is needed in order to sustain the southwestern Louisiana coastal wetlands.

From peripheral to core: a case study of a 3D printing firm on business ecosystems reconstruction

ABSTRACTThe rapid development of emerging digital technologies is giving peripheral firm, which is participant in secondary and complementary positions in a business ecosystem, unprecedented opportunities to shape its own ecosystem. Prior ecosystem studies mainly focus on the perspective of core firm, while few taking the perspective of peripheral firms. Using the case of a leading 3D printing firm in China, this study adopts resource orchestration as theoretical lens and investigates how a peripheral firm developed its business ecosystem and became a core firm in its own digital ecosystem. Specifically, this study identifies three stages of ecosystem development and the detailed processes and mechanisms, respectively. It contributes to the literature by exploring the ecosystem dynamics from an understudied perspective and identifying the processes and mechanisms of peripheral firms developing its ecosystem towards digital ecosystem. It also sheds lights for peripheral firms in existing business ecosystems in their business strategy development.

Oomycetes along a 120,000 year temperate rainforest ecosystem development chronosequence

Abstract The occurrence of plant-associated oomycetes in natural ecosystems and particularly during long-term ecosystem development is largely unknown. Using DNA sequencing, we investigated the frequency and host relationships of plant-root-associated oomycete communities along a 120 000 y glacial chronosequence, comprising site ages with rapid compositional change (“early succession”; 5–70 y old soil); relatively stable higher-diversity sites (“mature”, 280–12000 y); and ancient, nutrient-limited soils with declining plant biomass and stature (“retrogression”, 60 000, 120 000 y). Plant-associated oomycetes were frequent in early successional sites, occurring in 38–65% of plant roots, but rare (mean 3%) in all older ecosystems. Oomycete OTUs occurred non-randomly with plant host species, and were more frequent on those plant species that declined most strongly in abundance between ecosystem ages. While oomycetes were common in early succession, their absence in older sites suggests a limited role in later stages of ecosystem development.

Effects of canopy structure and species diversity on primary production in upper Great Lakes forests

Canopy structure and tree species diversity, shaped by succession, disturbance, and community composition, are linked to numerous ecosystem functions, including net primary production (NPP). Understanding of how ecosystem structural metrics are interrelated and mechanistically link to NPP, however, is incomplete. We characterized leaf area index (LAI), Simpson's index of Diversity (D', a measure of species diversity), and canopy rugosity (Rc, a measure of canopy physical complexity) in 11 forest stands comprising two chronosequences varying in establishing disturbance, and in three late successional communities. We related LAI, D', and Rc to wood NPP (NPPw), and examined whether absorption of photosynthetically active radiation and light use-efficiency (LUE) link NPPw with ecosystem structure. We found that recovery of LAI and D' was delayed following more severe establishing disturbances, but that the development of Rc was strikingly conserved regardless of disturbance, converging on a common mean value in late-successional stands irrespective of differences in leaf area index and species diversity. LAI was significantly correlated with NPPw in each stage of ecosystem development, but NPPw was only correlated with Rc in early successional stages and with D' in late successional stages. Across all stands, NPPw was coupled with LAI and Rc, (but not D') through positive relationships with light absorption and LUE. We conclude by advocating for better integration of ecological disciplines investigating structure-function interactions, suggesting that improved understanding of such relationships will require ecologists to traverse disciplinary boundaries.

Rapid soil formation after glacial retreat shaped by spatial patterns of organic matter accrual in microaggregates.

Global change contributes to the retreat of glaciers at unprecedented rates. The deglaciation facilitates biogeochemical processes on glacial deposits with initiating soil formation as an important driver of evolving ecosystems. The underlying mechanisms of soil formation and the association of soil organic matter (SOM) with mineral particles remain unclear, although further insights are critical to understand carbon sequestration in soils. We investigated the microspatial arrangement of SOM coatings at intact soil microaggregate structures during various stages of ecosystem development from 15 to >700years after deglaciation in the proglacial environment of the Damma glacier (Switzerland). The functionally important clay-sized fraction (<2μm) was separated into two density fractions with different amounts of organo-mineral associations: light (1.6-2.2g/cm3 ) and heavy (>2.2g/cm3 ). To quantify how SOM extends across the surface of mineral particles (coverage) and whether SOM coatings are distributed in fragmented or connected patterns (connectivity), we developed an image analysis protocol based on nanoscale secondary ion mass spectrometry (NanoSIMS). We classified SOM and mineral areas depending on the 16 O- , 12 C- , and 12 C14 N- distributions. With increasing time after glacial retreat, the microspatial coverage and connectivity of SOM increased rapidly. The rapid soil formation led to a succession of patchy distributed to more connected SOM coatings on soil microaggregates. The maximum coverage of 55% at >700years suggests direct evidence for SOM sequestration being decoupled from the mineral surface, as it was not completely masked by SOM and retained its functionality as an ion exchange site. The chemical composition of SOM coatings showed a rapid change toward a higher CN:C ratio already at 75years after glacial retreat, which was associated with microbial succession patterns reflecting high N assimilation. Our results demonstrate that rapid SOM sequestration drives the microspatial succession of SOM coatings in soils, a process that can stabilize SOM for the long term.

Biodiversity Promotion in Restored Mine Land through Plant-Animal Interaction

Ecological integrity includes enriched biodiversity, flourishing plant-animal interaction, and dynamic nutrient cycling. The present study examines the ecosystem structure and function of a newly developed ecosystem at a 24 year-old of restoration efforts in manganese mine area, Gumgaon, India. This study was initiated in the year 1988 through microbe assisted green technology (MAGT), which included application of top soil, site specific plantation, organic amendments and addition of soil microbes. The physico-chemical and biological properties of the reclaimed soil were gradually improved during the restoration programme with reference to soil pH, EC, bulk density, porosity, N, P, K, organic carbon, soil microbes, etc. Herbs occupied major ground cover with maximum density, followed by shrubs, trees and climbers. Regeneration capacity of the vegetation also followed the same pattern. An attempt was also made to analyse pollinator web with plant-pollinator interaction, influence of floral distribution on the composition of pollinator communities. The results of the study may help in understanding the linkage between plant and pollinator communities in ecorestoration programme. Four different groups of litter decomposing organisms, viz. microflora (bacteria, fungi, VAM), mircofauna (Nematoda), mesofauna (Protura, Enchytraeidae, Acari, Collembola) and macrofauna (Diplura, Isopoda, Isoptera, Chilopoda, Diplopoda, Coleoptera, Earthworms) have been studied. The present study clearly illustrates the sequence of various successional stages of ecosystem development from hostile ecological conditions of mine spoil to fully developed ecosystem and the study demonstrated how a barren land could be converted into a flourishing carbon sink.

Is spatially integrated entropy production useful to predict the dynamics of ecosystems?

Production of entropy by macroscopic systems in far from equilibrium as estimated from the spatial integration of entropy production density have been considered as an important concept that could help understand and predict the evolution of open systems. In this study we have used an extensive dataset of energy fluxes recorded in Ameriflux sites to compute the entropy production across different climates and ecosystems in order to analyze whether there are clear patterns showing a higher entropy production in more vegetated sites or in more developed stages. The entropy budget has been defined over a conceptualized system defined by the Earth's Critical Zone. Based on previous studies we have recognized four different formulations for the estimation of entropy production in macroscopic systems: (i) a total entropy production that accounts for all the energy fluxes including radiation fluxes, (ii) an entropy production that includes only those fluxes of energy absorbed within the open system, (iii) an entropy production that includes only living components and accounts for biochemical energy absorbed during photosynthesis and its further dissipation in the form of heat via respiration, and (iv) an entropy production that includes only incoming and outgoing heat fluxes into the open system that occurs at different temperatures. We quantified these entropy productions at different sites and stages of ecosystem development using available information recorded in 36 Ameriflux sites. We observed rather different magnitudes and patterns in all these formulations of the entropy production. Therefore, these formulations cannot be compared or considered as the same concept as has been done previously because they represent different scales and processes. In addition, we did not find a clear evidence of a maximum entropy production in more vegetated sites and at more mature stages of development, for any of these four entropy production formulations. These results suggest that hypotheses based on a maximum entropy production estimated from spatial integration over macroscopic systems in far from equilibrium should not be considered as a fundamental principle to understand or predict the evolution of these systems.

Strontium source and depth of uptake shifts with substrate age in semiarid ecosystems

AbstractWithout exogenous rock‐derived nutrient sources, terrestrial ecosystems may eventually regress or reach a terminal steady state, but the degree to which exogenous nutrient sources buffer or slow to a theoretical terminal steady state remains unclear. We used strontium isotope ratios (87Sr/86Sr) as a tracer and measured 87Sr/86Sr values in aeolian dust, soils, and vegetation across a well‐constrained 3 Myr semiarid substrate age gradient to determine (1) whether the contribution of atmospheric sources of rock‐derived nutrients to soil and vegetation pools varied with substrate age and (2) to determine if the depth of uptake varied with substrate age. We found that aeolian‐derived nutrients became increasingly important, contributing as much as 71% to plant‐available soil pools and tree (Pinus edulis) growth during the latter stages of ecosystem development in a semiarid climate. The depth of nutrient uptake increased on older substrates, demonstrating that trees in arid regions can acquire nutrients from greater depths as ecosystem development progresses presumably in response to nutrient depletion in the more weathered surface soils. Our results demonstrate that global and regional aeolian transport of nutrients to local ecosystems is a vital process for ecosystem development in arid regions. Furthermore, these aeolian nutrient inputs contribute to deep soil nutrient pools, which become increasingly important for maintaining plant productivity over long time scales.

Localized Effects of Coarse Woody Material on Soil Oribatid Communities Diminish over 700 Years of Stand Development in Black-Spruce-Feathermoss Forests

In the black-spruce clay-belt region of Western Québec, soil nutrients are limited due to paludification. Under paludified conditions, nutrient subsidies from decomposing surface coarse woody material (CWM) may be important particularly during the later stages of ecosystem development when deadwood from senescent trees has accumulated. For soil organisms, CWM can alter microclimatic conditions and resource availability. We compared abundance and species richness of oribatid mites below or adjacent to CWM across a chronosequence which spans ca. 700 years of stand development. We hypothesized that oribatid abundance and richness would be greater under the logs, particularly in later stages of forest development when logs may act as localized sources of carbon and nutrients in the paludified substrate. However, oribatid density was lower directly under CWM than adjacent to CWM but these differences were attenuated with time. We suggest that oribatids may be affected by soil compaction and also that such microarthropods are most likely feeding on recently fallen leaf litter, which may be rendered inaccessible by the presence of overlying CWM. This may also explain the progressive decline in oribatid density and diversity with time, which are presumably caused by decreases in litter availability due to self-thinning and Sphagnum growth. This is also supported by changes of different oribatid trophic groups, as litter feeders maintain different numbers relative to CWM with time while more generalist fungi feeders only show differences related to position in the beginning of the succession.

Progressive and retrogressive ecosystem development coincide with soil bacterial community change in a dune system under lowland temperate rainforest in New Zealand

It is established that plant communities show patterns of change linked to progressive and retrogressive stages of ecosystem development. It is not known, however, whether bacterial communities also show similar patterns of change associated with long-term ecosystem development. We studied soil bacterial communities along a 6,500 year dune chronosequence under lowland temperate rain forest at Haast, New Zealand. Pyrosequencing of 16S rRNA genes was used to observe structural change in bacterial communities during the process of pedogenesis and ecosystem development. Bacterial communities showed patterns of change during pedogenesis, with the largest change during the first several hundred years after dune stabilization. The most abundant bacterial taxa were Alphaproteobacteria, Actinobacteria and Acidobacteria. These include taxa most closely related to nitrogen-fixing bacteria, and suggest heterotrophic nitrogen input may be important throughout the chronosequence. Changes in bacterial community structure were related to changes in several soil properties, including total phosphorus, C:N ratio, and pH. The Bacteroidetes, Actinobacteria, Cyanobacteria, Firmicutes, and Betaproteobacteria all showed a general decline in abundance as pedogenesis proceeded, while Acidobacteria, Alphaproteobacteria, and Plantctomycetes tended to increase as soils aged. There were trends in the dynamics of bacterial community composition and structure in soil during ecosystem development. Bacterial communities changed in ways that appear to be consistent with a model of ecosystem progression and retrogression, perhaps indicating fundamental processes underpin patterns of below and above-ground community change during ecosystem development.

Mycorrhizas and mycorrhizal fungal communities throughout ecosystem development

Plant communities and underlying soils undergo substantial, coordinated shifts throughout ecosystem development. However, shifts in the composition and function of mycorrhizal fungi remain poorly understood, despite their role as a major interface between plants and soil. We synthesise evidence for shifts among mycorrhizal types (i.e., ectomycorrhizas, arbuscular and ericoid mycorrhizas) and in fungal communities within mycorrhizal types along long-term chronosequences that include retrogressive stages. These systems represent strong, predictable patterns of increasing, then declining soil fertility during ecosystem development, and are associated with coordinated changes in plant and fungal functional traits and ecological processes. Mycorrhizal types do not demonstrate consistent shifts through ecosystem development. Rather, most mycorrhizal types can dominate at any stage of ecosystem development, driven by biogeography (i.e., availability of mycorrhizal host species), plant community assembly, climate and other factors. In contrast to coordinated shifts in soil fertility, plant traits and ecological processes throughout ecosystem development, shifts in fungal communities within and among mycorrhizal types are weak or idiosyncratic. The consequences of these changes in mycorrhizal communities and their function for plant–soil feedbacks or control over long-term nutrient depletion remain poorly understood, but could be resolved through empirical analyses of long-term soil chronosequences.

Variable ecosystem response to climate change during the Holocene in northern Minnesota, USA

Both terrestrial and aquatic ecosystems should respond to abrupt climate changes such as those that affected the midcontinent of North America during the Holocene. A variety of paleorecords indicate that the onset of prolonged dry conditions in this region occurred as rapidly as 300 yr during the early Holocene, with a subsequent increase in moisture occurring rapidly in the late Holocene. Here, we report a 9500 yr multiproxy sediment record from Deming Lake, Minnesota, USA, that demonstrates only subtle dynamics during rapid climate changes that caused vegetation in the catchment to shift among pine forest, open grassland, and deciduous forest. The most substantial changes in ecosystem properties immediately followed deglaciation of the landscape, formation of the lake, and initial development of pine forests. In contrast, there were only muted responses to pronounced mid-Holocene climate changes that caused vegetation in the catchment to switch from pine forest to open grassland (ca. 8000 yr B.P.), and then deciduous forest (ca. 5400 yr B.P.). The flux of organic and inorganic terrigenous material, the processing of carbon, and catchment erosion changed rapidly during the most recent shift at 3300 yr B.P. to the modern pine forest. These changes coincided with the onset of meromictic conditions that influenced internal lake dynamics. However, the terrestrial influence on the lake sedimentary record gradually diminished over time, indicating a trajectory of increasing catchment stabilization that was relatively impervious to dramatic regional climate changes. The relative complacency of the Deming Lake record during the late Holocene indicates relative resistance to abrupt climate change at later stages of ecosystem development.

A simple method for determining limiting nutrients for photosynthetic crusts

Background: Photosynthetic crust communities are important to the functioning of many desert and early successional ecosystems. Little is known about the factors that limit the growth of these communities, especially during early stages of primary succession or following disturbance. Aims: Our main goal was to develop a method to study nutrient limitations of crust growth in laboratory microcosms. We used the new method to test the hypothesis that phosphorus limits the growth of crusts in newly deglaciated soils of the high Andes. Methods: We modified the point–intercept method used in plant ecology to quantify the spread of cyanobacteria, algae and mosses on the soil surface in response to additions of nitrogen and phosphorus. Results: Fertilization with phosphorus significantly increased the growth rate and final percentage cover, and decreased the lag time for growth of cyanobacterial and algal communities in recently deglaciated soils. By contrast, nitrogen additions had no significant effect on the growth of microbial phototrophs, and all nutrient additions suppressed the growth of early successional mosses. Conclusions: We propose that the method described here offers a valuable tool for assessing the nature of nutrient limitation of photosynthetic organisms in early successional and desert ecosystems. The information provided by using this approach can increase our understanding of the earliest stages of ecosystem development and may help inform strategies for the reclamation of disturbed arid ecosystems by identifying potential limiting nutrients.

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

Abstract. This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m−2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

Scots pine (Pinus sylvestris L.) ecosystem macronutrients budget on reclaimed mine sites—stand trees supply and stability

The aim of this study was to determine the sources, accumulation rate and relationships between macronutrients in reclaimed mine soils (RMS) and aboveground plant biomass on external slopes of lignite mines in central Poland. The study was conducted on two different types of sites with 10-year-old Scots (Pinus sylvestris L.) pine stands located on Quaternary loamy sands (QLS) and on Tertiary acidic carboniferous sands following neutralisation (TCS). The control plot was located in the same vicinity on an external slope in a natural pine ecosystem on a Haplic Podzol in a young mixed coniferous forest habitat (NPE). The nutrient resources, apart from N, were higher in RMS than in comparable Haplic Podzols, however, N primarily accumulated in the mineral horizons. In forest soils, the main macronutrient resources were accumulated in organic horizons, which in natural soils of coniferous forest habitats constitute the main source of nutrients. The proportion of individual macronutrients accumulated in the biomass vs. pools in soil was much lower on the external slope RMS than in the natural site, which in view of the potential richness of RMS, indicated poorer sorption and utilization of macronutrients in aboveground plant biomass than in natural habitats. Other important linear correlations (p = .05) were found between the sources of nutrients in RMS and elements accumulated in biomass (most clearly in case of K, Ca and Mg), which indicates important relationships between soil and vegetation in the first stages of ecosystem development as stimulated by reclamation.

Macronutrient Accumulation and Relationships in a Scots Pine (Pinus Sylvestris L.) Ecosystem on Reclaimed Opencast Lignite Mine Spoil Heaps in Central Poland

The aim of this study was to determine the sources, accumulation rate and relationships between macronutrients in reclaimed mine soils (RMS) and aboveground plant biomass on external slopes of lignite mines in central Poland. The study was conducted on two different types of sites with 10-year-old Scots (Pinus sylvestris L.) pine stands located on Quaternary loamy sands (QLS) and on Tertiary acidic carboniferous sands following neutralisation (TCS). The control plot was located in the same vicinity on an external slope in a natural pine ecosystem on a Haplic Podzol in a young mixed coniferous forest habitat (NPE). The nutrient resources, apart from N, were higher in RMS than in comparable Haplic Podzols, however, N primarily accumulated in the mineral horizons. In forest soils, the main macronutrient resources were accumulated in organic horizons, which in natural soils of coniferous forest habitats constitute the main source of nutrients. The proportion of individual macronutrients accumulated in the biomass vs. pools in soil was much lower on the external slope RMS than in the natural site, which in view of the potential richness of RMS, indicated poorer sorption and utilization of macronutrients in aboveground plant biomass than in natural habitats. Other important linear correlations (p=.05) were found between the sources of nutrients in RMS and elements accumulated in biomass (most clearly in case of K, Ca and Mg), which indicates important relationships between soil and vegetation in the first stages of ecosystem development as stimulated by reclamation.

Community Differentiation Along a Dune Succession: An Experimental Approach With Corprophilous Fungi

Exposure of laboratory—collected rabbit feces in different habitats associated with a dune succession in Presque Isle State Park, Erie, Pennsylvania, USA, affected the structure and composition of the coprophilous fungal communities developing on these feces. Nylon mesh litter bags containing 4—g samples of rabbit feces, the latter incorporating a similar fungal inoculum, were exposed in the field for either 2— or 4—wk intervals throughout the summer of 1975. This was followed by a 40—d incubation in laboratory moist chambers, during which time the development (sporulation) of fungal populations was studied and the frequency of occurrence of fungal taxa recorded. Community analysis was accomplished by position vectors ordination, and analysis of species diversity values. Experimental evidence is offered for the first time that microclimatic amelioration and stabilization in later stages of ecosystem development can be important in determining microfungal diversity. Community diversity increased when dune habitat and/or exposure interval were associated with a less stressful environment (i.e., presence of vegetational cover or greater available moisture).