scholarly journals AGARICOID BASIODIMYCETES IN PETROZAVODSK CITY GREEN SPACES (REPUBLIC OF KARELIA)

2018 ◽  
Vol 8 (1) ◽  
pp. 52-71
Author(s):  
Леонид Савельев ◽  
Leonid Savel'ev ◽  
Анастасия Кикеева ◽  
Anastasiya Kikeeva
Keyword(s):  
Trophic Structure ◽  
Forest Tree ◽  
Middle Taiga ◽  
Taxonomic Structure ◽  
Boreal Zone ◽  
Forest Zone ◽  
Number Of Species ◽  
Spruce Stands ◽  
Leading Position ◽  
Nomic Structure

The paper reports the results of studies on the taxonomic and trophic structure of agaricoid basidiomycetes in urban stands of the main forest tree species of the boreal zone (Betula, Larix, Picea, Pinus). Altogether 111 species of macromycetes of 59 genera, 33 families and 8 orders were found. The leader in terms of the number of species in this mycobiota is the group of mycorrhiza-forming fungi. The biota of agaricoid fungi is of the boreal type with the taxo-nomic structure most vividly demonstrating the traits of the mycobiota typical of the middle taiga subzone of Karelia. A distinctive feature of the mycobiota is the high number of species in the families Agaricaceae and Russulaceae, which are common in ruderal habitats and the forest zone. A comparison of the species composition and ratios in the taxonomic structure of the mycobiota between plant communities of urban and undisturbed areas, as well as Karelia in general showed a low level of similarity and pointed to gaps in the current inventory of agarics in the boreal zone of Republic. The highest species diversity of macromycetes was found in spruce stands, and the lowest in larch stands. The structure of the agaricoid fungal biota in sample plots in the spruce-, birch- and larch stands was relatively stable, with some fluctuation. As to the structure of the pine stand mycobiota, the spectrum of families ranked by the number of species in them changed along the human pressure gradient, and the trophic structure changed accordingly. The number of symbiotrophic species decreased, litter-related saprotrophs disappeared, the leading position was taken over by humus-related saprotrophs. The surveys revealed the presence of 11 red-listed species classified into two categories – near threatened (NT) and data deficient (DD) species.

scholarly journals DIVERSITY AND SUBSTRATE ECOLOGY OF LUCISPOROMYCETIDAE IN THE PYATYKHATSKYI FOREST (KHARKIV, UKRAINE)

2020 ◽  
pp. 21-26
Author(s):  
Т. Ю. Маркіна ◽  
Д. В. Леонтьєв
Keyword(s):  
Quercus Robur ◽  
Dead Wood ◽  
Taxonomic Structure ◽  
Tilia Cordata ◽  
Acer Platanoides ◽  
Number Of Species ◽  
The Family ◽  
Different Types ◽  
Leading Position ◽  
Total Species

As a result of the field study, carried out in June 2019, 34 species of bright-spored myxomycetes from 11 genera, 5 families and 4 orders of the subclass Lucisporomycetidae were collected in the Pyatykhatskyi Forest Massif, PFM (Kharkiv, Ukraine). Among the found orders of the myxomycetes, Trichiales (20 species) prevails by number of species, demonstrating much larger diversity, than Cribrariales (7 species), Reticulariales (5) and Liceales (2). Among the families of the Lucisporomycetidae, the leading position is occupied by Trichiaceae (19 species); the rest of the families revealed the fewer number of species. Among the genera of myxomycetes, Cribraria Pers., Trichia Haller, and Arcyria F.H. Wigg. were the most abundant regarding the number of species. The species from the five leading genera represent 70.6% of the total species diversity of Lucisporomycetidae in PFM. All the myxomycetes species were found on substrates formed by tree plant species; only Arcyria cinderea, Hemitrichia serpula and Tubifera ferruginosa were also found on bryophyte, while A. denudata was also collected on the wet soil. Among the substrates formed by woody plants, the two-thirds of myxomycete species were observed on the dead wood. On the substrates formed by Quercus robur, Acer platanoides and Tilia cordata, 18 species of myxomycetes were found, including 14, 12, and 4 species on each of these substrate-forming plants, respectively. The taxonomic structure of the myxomycete biota on different types of substrate-forming plants is significantly different. On Tilia cordata, Fraxinus excelsior and Quercus robur more than half of the taxonomic spectrum is formed by species of Trichiaceae, on the Pinus sylvestris the family Cribrariaceae dominates, while on A. platanoides species from the Reticularaceae appear to be the most diverse. The presence of the only representative of Dianemataceae, C. metallica, found on the bark of T. cordata, and a moderate diversity of Liceaceae on F. excelsior seem to be noteworthy. The data obtained allow us to characterize the biota of the brightspored myxomycetes of the PFM as mostly xylophilic, with a predominance of Cribrariales and Trichiales and a tendency of sporulation on the dominant species of forest-forming plants.

Peculiarities of seasonal changes of taxonomic structure and number of weevil-beetles (Coleoptera, Curculionidae) of herptobios in Kharkiv urbocenoses (Ukraine)

2019 ◽  
Vol 16 (1) ◽  
pp. 25-35 ◽  
Author(s):  
N.A. Komaromi ◽  
A.V. Putchkov ◽  
V.Yu. Nazarenko
Keyword(s):  
Early Summer ◽  
Taxonomic Structure ◽  
Dynamic Density ◽  
Number Of Species ◽  
Summer Maximum ◽  
Minimal Quantity ◽  
Slight Rise ◽  
Suburban Forests ◽  
The City ◽  
Increased Activity

A total of 54 species in 35 genera of Curculionidae are registered in the urbocenoses of Kharkiv city. Only three species, Exomias pellucidus, Otiorhynchus raucus and Ot. ovatus, are recorded as dominants. Some other species (Urometopus nemorum, Sciaphobus squalidus and Glocianus punctiger) are sporadically noted in some sites as subdominants. The total number of species turned out to be higher in the herpetobios of plantings at periphery (31), slightly lower in private farmlands of the city (21), parks and plantings of the center (17 each), but minimal in suburban forests (11 species). The highest quantity of specimens were observed for the plantations of the center and margins of city: nevertheless, minimal quantity of specimens was registered at parks and woods. The maximum number of species (including all cenoses) was recorded from the end of April to first decade of May (28 species). From May to the end of June 15–18 species were registered. Ten species were recorded at July, and only six species at August. A slight rise was noted from the end of August to mid-September (11 species). In biotopes where Exomias pellucidus appeared to be the monodominant, the seasonal dynamic density of weevils reached a peak at late May or early June, but the significant decline was observed from early June to July. At the sites with several dominants, two or three peaks were registered: at spring (May) and at mid-summer (end of June or beginning of July). Furthermore, the number of weevils decreased gradually, but some species of Curculionidae were rather abundant even from the end of summer to September–October. The spring increase is reasoned by high density of species in the genus Otiorhynchus; the peak in early summer (maximum) is caused by the increased activity of majority of dominant species; the autumn peak is also caused by the high number of species of the genus Otiorhynchus. The level of sex index (by the example of E. pellucidus) differed significantly at all plots. It was higher for the plantations at the periphery of the city (0.70), and it was minimal at private farmlands (0.20). Relative conjugacy of sex index and dynamic density were not observed: the maximum abundances of quantity of Curculionidae were recorded 20–30 days earlier than the maximal numbers of the sex index.

THE STRUCTURAL AND FUNCTIONAL CHARACTERISTIC OF MACROZOOBENTHOS OF LAKE ZAKITNE

2021 ◽  
pp. 7-14
Author(s):  
Alexenko T. ◽  
Shevchenko I.
Keyword(s):  
Energy Balance ◽  
Benthic Invertebrates ◽  
Trophic Structure ◽  
Functional Characteristic ◽  
Benthic Invertebrate ◽  
Taxonomic Structure ◽  
Total Production ◽  
Food Ration ◽  
Structural And Functional Properties ◽  
Glyptotendipes Glaucus

For the first time, systematic studies of the structural and functional properties of macrozoobenthos of Lake Zakіtne were conducted. A taxonomic list of macroinvertebrates with their zoogeographical characteristics is given. According to the results of research, 3 types of benthic invertebrate groups were identified and described, of which Oligochaeta-Chironomidae type were the most widespread. Only two species were common to all found groups: Einfeldia longipes and Glyptotendipes glaucus of Chiromonidae family. The calculated biotic indices indicate a fairly high degree of use of existing biotopes by macroinvertebrates, as well as the predominance of species characteristic of the α-β-mesosaprobic zone.The variety of ways and mechanisms of feeding of benthic invertebrates is shown. Collectors, scraper collectors, sedimentators, filter feeders, shredders, predators, as well as macroinvertebrates with an indeterminate feeding type were identified in the trophic structure by the predominant type of feeding. The number of species, as well as their representation in trophic groups, varied in different years, yet 54-73% of them were nonpredatory forms.According to the obtained data, the components of the energy balance for macroinvertebrates were calculated. The active participation in the production of organic matter of Chironomidae larvae (from 29 to 62% of the total production of nonpredatory and predatory forms) is indicated. In some years, Ephemeroptera and Mollusca were actively involved in production. The largest flow of energy passed through insects (Ephemeroptera, Trichoptera) and leeches. Attention is drawn to the role of predators, which can significantly reduce the production of groups. High production and food ration of predators do not allow to ignore them when calculating the production of the entire zoocenosis.In average, during the vegetation season, the total production of nonpredatory and predatory benthic invertebrates was 77,89 kJ/m2, and the predator's food ration was 61,80 kJ/m2.Key words:macroinvertebrates, taxonomic structure, trophic structure, community, production, food ration, energy balance. Вперше проведено систематичні дослідження структурно-функціональних властивостей макрозообентосу озера Закітне. Наведено таксономічний список макробезхребетних з їх зоогеографічною характеристикою. За результатами досліджень виявлено та описано 3 типи угруповань донних безхребетних, з яких найбільшепоширення отримали олігохетно-хірономідні комплекси. Лише двавиди виявилися спільними для всіх знайдених угруповань: Einfeldia longipes і Glyptotendipes glaucus (родина Chironomidae).Розраховані біотичні індекси свідчать про достатньо високий ступень використання існуючих біотопів макробезхребетними, а також про переважання видів, що характерні для α-β-мезосапробної зони.Показанарізноманітність способів і механізмів живлення донних безхребетних. У трофічній структурі угруповань за переважаючим способомживлення було виділено збирачів, збирачів-шкребачів, седиментаторів, фільтраторів, подрібнювачів, хижаків, а також макробезхребетних із невизначеним типом живлення. Кількість видів, а також їх представленість утрофічних групах в різні роки була неоднакова, але на 54–73% це були мирні форми.За отриманими даними було розраховано складові енергетичного балансу за макробезхребетними. Вказано на активну участь упродукуванні органічної речовини личинок родини Chironomidae, яким належить від 29 до 62% від сумарної продукції мирних і хижих форм. В окремі роки в продукування активно включалися одноденки та молюски. Найбільший потік енергії проходив через комах (Ephemeroptera, Trichoptera) і п’явок. Звернуто увагу на роль хижаків, які можуть суттєво знижувати продукцію угруповань. Високапродукція і раціон хижаків не дозволяють нехтувати ними при розрахунку продукції всього ценозу.Підраховано, що в середньому за вегетаційний період сумарна продукція мирних і хижих донних безхребетних дорівнювала 77,89 кДж/м2, а раціон хижаків складав 61,80 кДж/м2.Ключові слова: макробезхребетні, таксономічна структура, трофічна структура, угруповання, продукція, раціон, енергетичний баланс.

Coprophilous ascomycetes of the Oleshkivski Pisky National Nature Park (Kherson region, Ukraine)

2021 ◽  
Vol 17 (1) ◽  
pp. 81-91
Author(s):  
Lytvynenko Yu.I. ◽  
Romanova D.A. ◽  
Orlova-Hudіm K.S. ◽  
Hudіm A.O. ◽  
Vakal A.P.
Keyword(s):  
New Records ◽  
Steppe Zone ◽  
General Distribution ◽  
Mycological Research ◽  
Widespread Species ◽  
Number Of Species ◽  
The World ◽  
Leading Position ◽  
Nature Park ◽  
First Time

As a result of mycological research 34 species of coprophilous ascomycetes from 14 genera, 10 families, and 5 orders were recorded on the territory of the Oleshkivski Pisky National Nature Park. Among them 15 species belonged to the class Sordariomycetes, 12 – to Dothideomycetes, and 7 – to Pezizomycetes. Among the orders of the fungi, Sordariales – 12 species, Pleosporales – 11, and Pezizales – 7, occupy the leading position; the rest of the orders revealed the fewer number of species. Among the families, Sporormiaceae, Podosporaceae, Coniochaetaceae, Delitschiaceae, and Sordariacea, were the most abundant regarding the number of species and specimens. The species from the five leading families represent 64,7% of the total number of identified species. Among the found genera of the coprophilous ascomycetes, Coniochaeta, Delitschia, Sordaria, Sporormiella, and Triangularia prevailed by number of species, demonstrating much larger diversity, than others. Environmental conditions inside the park are more favorable for the development of loculoascomycetes and pyrenomycetes. The discomycetes species diversity was much less. The list of recorded fungi and their substrates is presented. All species of ascomycetes were collected on the hare and cattle excrements. Other dung types have not been studied. 31 species are new to the territory of the park, 15 species are new records for the steppe zone of Ukraine. Coniochaeta hansenii and Sporormiella tetramera are first recorded in Ukraine. Descriptions, illustrations, synonyms and general distribution are provided for them. C. hansenii is a fairly common and widespread species in the world, occurring mainly on the leporid droppings. In the park, this species was also collected on hare dung. S. tetramera also belongs to the widespread but rare species of coprophilous ascomycetes, known from isolated records in a few countries. It was collected on the hare excrements in the park. Сoniochaeta leucoplaca, Delitshia perpusilla and Triangularia comata were collected for the first time in the steppe zone of Ukraine and for the second time in the country. У результаті дослідження копрофільних аскоміцетів Національного природного парку «Олешківські піски» було виявлено 34 види грибів із 14 родів, 10 родини та 5 порядків. Це представники трьох класів: Sordariomycetes – 15 видів, Dothideomycetes – 12, Pezizomycetes – 7. Серед порядків найчисельнішими є Sordariales – 12 видів, Pleosporales – 11 та Pezizales – 7. У родинному спектрі грибів переважають представники Sporormiaceae, Podosporaceae, Coniochaetaceae, Delitschiaceae та Sordariacea, які об’єднують 64,7% загальної кількості виявлених видів аскоміцетів. Серед родів переважають Coniochaeta, Delitschia, Sordaria, Sporormiella та Triangularia. Екологічні умови території парку є більш сприятливими для розвитку локулоаскоміцетів і піреноміцетів. Кількість знахідок видів дискоміцетів є незначною. Представлено список зареєстрованих видів грибів, для кожного виду вказано локалітети та живильні субстрати. Всі види грибів зібрані на посліді зайця та корови. Інші типи копром не досліджувались. З виявлених видів аскоміцетів 31 наводиться вперше для території парку, 15 є новими для степової зони України. Два види аскоміцетів є новими для мікобіоти України та Східної Європи: Coniochaeta hansenii та Sporormiella tetramera. У статті представлено їх діагнози та фото, обговорюються деталі морфології, субстратної приуроченості та поширення у світі. C. hansenii є досить звичайним та поширеним у світі видом, що переважно трапляється на екскрементах зайцеподібних.На території парку також була зібрана на копромах зайця. S. tetramera належить до поширених у світі, але рідкісних видів копрофільних аскоміцетів, відомих з поодиноких знахідок у небагатьох країнах. У парку зібрана на посліді зайця. Знахідки Сoniochaeta leucoplaca, Delitshia perpusilla та Triangularia comata є новими для території степової зони України та вдруге наводяться для нашої держави.

scholarly journals Effect of forest tree species on the humus form state at lower altitudes 

2012 ◽  
Vol 51 (No. 2) ◽  
pp. 60-66 ◽  
Author(s):  
V. V Podrázský ◽  
J. Remeš
Keyword(s):  
Organic Matter ◽  
Species Composition ◽  
Site Effects ◽  
Nutrient Dynamics ◽  
Forest Tree ◽  
Negative Effects ◽  
Litter Accumulation ◽  
Spruce Stands ◽  
Humus Form ◽  
Humus Accumulation

  The paper documents the effects of forest stands of different species composition on the humus form state and soil profile chemistry. It compares the situation in mixed broadleaved (ash, oak, hornbeam), basswood and spruce stands. Spruce demonstrates the site degradation effects: raw humus accumulation, soil acidification, negative effects on nutrient dynamics. Both broadleaved stands were similar as for site effects, lower litter accumulation, more rapid organic matter mineralization and more rapid nutrient cycling and intense uptake were documented in the basswood stand.  

scholarly journals CHARACTERISTICS OF FLORA IN SAMARA ZAVOLZHIE NEPOTISTIC SPECTRUM

2015 ◽  
Vol 4 (2) ◽  
pp. 86-89
Author(s):  
Anastasiy Viktorovna Ivanova ◽  
Natalia Viktorovna Kostina
Keyword(s):  
Climatic Factors ◽  
Volga Basin ◽  
Forest Steppe ◽  
Taxonomic Structure ◽  
Natural Zones ◽  
Number Of Species ◽  
The North ◽  
Ulyanovsk Region ◽  
The Republic ◽  
Families First

It is known that the flora reacts on changing of composition climatic factors. Changing the composition of the head of the nepotistic spectrum, which is determined by the type of flora (first triada). Samara Region is located in Fab-zone, which in the territory of the Volga basin covers Saratov, Samara, Ulyanovsk region and the Republic of Tatarstan. In the north-western part of the Volga basin it gradually becomes Ros-zone. Changes in the composition of flora has discrete-continuous in nature. Flora in different parts of Fab-zone has its own characteristics, which is reflected in the taxonomic parameters. Most of the Samara Region is located in Zavolzhie, which forms the border of natural zones: forest-steppe and steppe. The natural conditions of these territories have their differences, and, therefore, differ in the parameters flora. The article reveals differences in the taxonomic structure of the flora of the steppe and forest-steppe part of the Samara region. These differences manifest themselves in different share of participation Fabaceae and Rosaceae. In the steppes of Samara Zavolzhja weakened the role of the family Rosaceae and enhanced Chenopodiaceae. Taxonomic analysis shows that the composition of the leading families first triad of the spectrum depends on the number of species in the description. The more species, the greater the likelihood that established triad leading families, corresponding to the zone. If the number of species in the description 500, then the leading triads stabilized.

scholarly journals A collection of the decorative plants of the Polar Experimental Station Branch VIR

2021 ◽  
pp. 7-16
Author(s):  
A. S. Babkova
Keyword(s):  
Ornamental Plants ◽  
Life Forms ◽  
Taxonomic Structure ◽  
Dominant Position ◽  
Herbaceous Perennials ◽  
Experimental Station ◽  
Number Of Species ◽  
Main Work ◽  
The Family ◽  
Growing Conditions

The article presents a taxonomic analysis for the decorative plants collection in the Polar Experimental Station of the VIR branch. The collection fund of floral and ornamental plants of the VIR Polar Experimental Station currently contains 208 species, 90 cultural forms and varieties from 53 families. The collection of annual crops is represented by 21 genera, 22 species, 69 varieties from 14 families. Perennial herbaceous decorative plants on the Polar OS VIR have 101 genera, 140 species from 40 families. The collection of decorative shrubs at the Polar Experimental Station consists of 20 genera, 47 species from 11 families. From the collection of herbaceous floral and decorative crops, the plants from the Asteraceae family are most represented. The Asteraceae occupies a dominant position in the collection of annuals in terms of the number of species and varieties (8 genera, 9 species, 24 varieties). The families Solanaceae and Violaceae each have one species, but the number of cultivars cultivated at the station (9 and 18, respectively) makes it possible to distinguish them from the general composition of the collection of annuals. Among the decorative herbaceous perennials, the largest number of species (≥10) are the families: aster (18 genera, 24 species), buttercup (7 genera, 12 species), carnation (5 genera, 10 species), rosaceae (7 genera, 10 species). The family Rosaceae in the collection of decorative shrub plants is predominant in number and has 10 genera and 29 species. All decorative plants of the VIR Polar Experimental Station nursery of different life forms are introduced. The main work is aimed at attracting modern varieties, new species, and intraspecific forms to the collection. The analysis of the taxonomic structure of plant species, varieties and forms allows us to identify and recommend the most resistant to extreme growing conditions plants that have high decorative qualities, taking into account modern trends in urban floristics.

scholarly journals Vegetation changes in beech and spruce stands in the Orlické hory Mts. in 1951–2001

2012 ◽  
Vol 49 (No. 10) ◽  
pp. 445-473 ◽  
Author(s):  
S. Vacek ◽  
K. Matějka
Keyword(s):  
Species Diversity ◽  
Species Number ◽  
Vegetation Changes ◽  
Developmental Trend ◽  
Herb Layer ◽  
Point Scale ◽  
Number Of Species ◽  
Beech Stand ◽  
Spruce Stands ◽  
Very High

Plant cenological surveys on the basis of Braun-Blanquet’s seven-point scale were made on 34 research plots in the course of studies of vegetation changes in beech and spruce stands in the Orlické hory Mts. over period of 1951–2001. The acquired data were processed not only by traditional plant coenological methods but also by numerical analyses (agglomerative and divisive classification, ordination, species diversity). The results document marked changes that occurred in species-rich spruce communities of the association Athyrio alpestre-Piceetum (Aa-P) as well as in species-poorer communities of the associations Vaccinio myrtilli-Piceetum (Vm-P), Calamagrostio villosae-Piceetum (Cv-P) and Deschampsio flexuosae-Piceetum (Df-P). The developmental trend of these communities in 1971–1991 converged on types very poor in species (Df-P association). On the contrary, the period 1991–2001 was characterised by a marked increase in the number of species, especially in the herb layer. An increase in coverage and number of tree species seedlings was very high after the productive seed years 1992 and 1995. The acceleration of changes in beech stands in 1971–1991 led to a species number diminution in herb-rich types of the association Dentario enneaphylli-Fagetum (De-F), and/or to their transition to species-poorer acidophilous types Calamagrostio villosae-Fagetum (Cv-F). Similarly like in spruce stands the number of species in beech stand relevés increased in 1991–2001. But a majority of typical species of herb-rich beech stands returned to the communities under study very slowly.

ARTHROPOD BIODIVERSITY FROM POPULUS COARSE WOODY MATERIAL IN NORTH-CENTRAL ALBERTA: A REVIEW OF TAXA AND COLLECTION METHODS

1997 ◽  
Vol 129 (6) ◽  
pp. 1009-1033 ◽  
Author(s):  
H.E. James Hammond
Keyword(s):  
Trophic Structure ◽  
Feeding Habits ◽  
North Central ◽  
Number Of Species ◽  
Collecting Methods ◽  
Saproxylic Species ◽  
Window Traps ◽  
Arthropod Biodiversity ◽  
Collection Methods ◽  
Coarse Woody Material

AbstractArthropods associated with Populus coarse woody material (CWM) were sampled from aspen-mixedwood stands in north-central Alberta using rearings from wood bolts and flight-intercept traps attached to snags. More than 39 000 arthropod specimens were collected over 3 years, comprised mainly of Coleoptera, Diptera, Hymenoptera, and Acari. Detailed analyses are provided to compare the number of species, standardized abundance, and trophic structure between collecting methods for 257 saproxylic species of Coleoptera. Abundance of beetle species, from both rearings and window traps, and rarefaction estimates of species richness indicate little difference between methods with respect to expected number of species. However the abundance of particular beetle families differed significantly between methods, with the Aderidae, Anthicidae, and Scaphidiidae collected mainly in rearings and the Micropeplidae, Bostrichidae, Cephaloidae, Clambidae, Salpingidae, and Tenebrionidae more commonly collected with window traps. Fungivorous and predatory beetles were more abundant in CWM than wood borers, scavengers, or taxa with undetermined feeding habits, but the two methods revealed similar overall trophic structure. To census the variability in saproxylic arthropod faunas from CWM, a combination of collecting methods is recommended.

Stochastic structure and nonlinear dynamics of food webs: qualitative stability in a Lotka-Volterra cascade model

1990 ◽  
Vol 240 (1299) ◽  
pp. 607-627 ◽  
Keyword(s):  
Population Dynamics ◽  
Food Webs ◽  
Trophic Structure ◽  
Three Dimensional ◽  
Cascade Model ◽  
Volterra Model ◽  
Critical Surface ◽  
Dimensional Parameter ◽  
Globally Asymptotically Stable ◽  
Number Of Species

Two competing models currently offer to explain empirical regularities observed in food webs. The Lotka-Volterra model describes population dynamics; the cascade model describes trophic structure. In a real ecological community, both population dynamics and trophic structure are important. This paper proposes and analyses a new hybrid model that combines population dynamics and trophic structure: the Lotka-Volterra cascade model (LVCM). The LVCM assumes the population dynamics of the Lotka-Volterra model when the interactions between species are shaped by a refinement of the cascade model. A critical surface divides the three-dimensional parameter space of the LVCM into two regions. In one region, as the number of species becomes large, the limiting probability that the LVCM is qualitatively globally asymptotically stable is positive. In the region on the other side of the critical surface, and on the critical surface itself, this limiting probability is zero. Thus the LVCM displays an ecological phase transition: gradual changes in the probabilities of various kinds of population dynamical interactions related to feeding can have sharp effects on a community’s qualitative stability. The LVCM shows that an inverse proportionality between connectance and the number of species, and a direct proportionality between the number of links and the number of species, as observed in data on food webs, need not be directly connected with the qualitative global asymptotic stability or instability of population dynamics. Empirical testing of the LVCM will require field data on the population dynamical effects of feeding relations.

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