Biodiversity of floodplain river ecosystems: ecotones and connectivity1

Regulated Rivers Research & Management, Год журнала: 1999, Номер 15(1-3), С. 125 - 139

Опубликована: Янв. 1, 1999

A high level of spatio-temporal heterogeneity makes riverine floodplains among the most species-rich environments known. Fluvial dynamics from flooding play a major role in maintaining diversity lentic, lotic and semi-aquatic habitat types, each represented by successional stages. Ecotones (transition zones between adjacent patches) connectivity (the strength interactions across ecotones) are structural functional elements that result contribute to ecosystems. In floodplain rivers, ecotones their adjoining patches arrayed hierarchical series range scales. At coarse scale resolution, fringing themselves complex river channels uplands. finer scales, various types sizes form microhabitat patterns. broad perspective, including patterns processes is needed order gain insight into biodiversity. We propose framework for examining rivers. Various management schemes disrupt structure alter transition zones. Such disruptions occur both within levels, invariably leading reductions Species richness data connected disconnected Austrian Danube illustrate this clearly. much world, riverine/floodplain exist only as isolated fragments landscape. many large these islands biodiversity endangered The fluvial formed them have been severely altered. Without ecologically sound restoration disturbance regimes connectivity, remnants will proceed on unidirectional trajectories toward senescence, without rejuvenation. Principles ecosystem necessary sustain fragmented floodplains. Copyright © 1999 John Wiley & Sons, Ltd.

Язык: Английский

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Biodiversity inventories, indicator taxa and effects of habitat modification in tropical forest

Nature, Год журнала: 1998, Номер 391(6662), С. 72 - 76

Опубликована: Янв. 1, 1998

Язык: Английский

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Ecological Theory and Community Restoration Ecology

Restoration Ecology, Год журнала: 1997, Номер 5(4), С. 291 - 300

Опубликована: Дек. 1, 1997

Abstract Community ecological theory may play an important role in the development of a science restoration ecology. Not only will practice benefit from increased focus on theory, but basic research community ecology also benefit. We pose several major thematic questions that are relevant to perspective and, for each, identify specific areas critical need further advance ask, what appropriate endpoints perspective? The problem measuring at level, particularly given high amount variability inherent most natural communities, is not easy, and require function (e.g., trophic structure) rather than particular species. benefits limitations using species composition or biodiversity measures as ecology? Since reestablishing all native rarely be possible, needed relationship between richness stability restored sites functional redundancy among regional colonist “pools.” Efforts targeted restoring system must take into account individual species, if some disproportionate processing material strong interactors. habitat sufficient approach reestablish function? Many untested assumptions concerning physical structure being made practical efforts. rigorous testing these assumptions, determine how generally they apply different taxa habitats. extent can empirical theoretical work succession dispersal contribute distinguish systems which broadly applicable those it probably not. If highly predictable, feasible manipulate processes accelerate restoration. close by stressing so intertwined with efforts should rely heavily known communities develop structured over time.

Язык: Английский

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Are plant populations seed‐limited? A review of seed sowing experiments

Oikos, Год журнала: 2000, Номер 88(2), С. 225 - 238

Опубликована: Фев. 1, 2000

We define seed limitation to be an increase in population size following addition. Here, we briefly consider how theoretical models deal with and sowing experiments can used unravel the extent of natural systems. review two types addition experiments: augmentation studies where seeds are added existing populations; introductions sown unoccupied sites. Overall, approximately 50% show evidence limitation. These that tends occur more commonly early successional habitats species. Most have concentrated on simply categorising populations as seed‐ or microsite‐limited, but believe could reveal much about community structure, discuss possible future directions. In 53% introduction (where were at sites from which species was known absent) introduced recorded least one experimental sowing. However, subset both seedlings adult plants recorded, 64% contained while only 23% adults. This implies that, for many species, conditions establishment stringent than germination. The successful patches indicates potential immigration enhance local diversity (the spatial mass effect). Few continued monitoring long enough determine whether not self‐sustaining successfully established, no study attempted link a putative source propagules, considered dynamics metapopulation whole.

Язык: Английский

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The relative of species pools in determining plant species richness: an alternative explanation of species coexistence?

Trends in Ecology & Evolution, Год журнала: 1997, Номер 12(7), С. 266 - 269

Опубликована: Июль 1, 1997

Язык: Английский

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Ecological assembly rules in plant communities—approaches, patterns and prospects

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Год журнала: 2011, Номер 87(1), С. 111 - 127

Опубликована: Июнь 21, 2011

Understanding how communities of living organisms assemble has been a central question in ecology since the early days discipline. Disentangling different processes involved community assembly is not only interesting itself but also crucial for an understanding will behave under future environmental scenarios. The traditional concept rules reflects notion that species do co‐occur randomly are restricted their co‐occurrence by interspecific competition. This can be redefined more general framework where product chance, historical patterns speciation and migration, dispersal, abiotic factors, biotic interactions, with none these being mutually exclusive. Here we present survey meta‐analyses 59 papers compare observed plant null models simulating random assembly. According to type data study methods applied detect assembly, distinguish four main types approach published literature: co‐occurrence, niche limitation, guild proportionality limiting similarity. Results from our suggest non‐random widespread phenomenon. However, whether this finding individualistic nature or caused methodological shortcomings associated studies considered cannot discerned available metadata. We advocate thorough surveys conducted using set standardized test existence sets spanning larger biological geographical scales than have until now. underpin advice guidelines should research. enable us draw accurate conclusions about aspect communities.

Язык: Английский

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SPECIES CO-OCCURRENCE: A META-ANALYSIS OF J. M. DIAMOND'S ASSEMBLY RULES MODEL

Ecology, Год журнала: 2002, Номер 83(8), С. 2091 - 2096

Опубликована: Авг. 1, 2002

J. M. Diamond's assembly rules model predicts that competitive interactions between species lead to nonrandom co-occurrence patterns. We conducted a meta-analysis of 96 published presence–absence matrices and used realistic "null model" generate patterns expected in the absence interactions. Published were highly matched predictions model: there fewer combinations, more checkerboard pairs, less real than by chance. Moreover, structure was greater homeotherm vs. poikilotherm matrices. Although these analyses do not confirm mechanisms controversial model, they establish observed most natural communities is usually These results contrast with previous bridge apparent gap experimental correlative studies community ecology.

Язык: Английский

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The Roles of Harsh and Fluctuating Conditions in the Dynamics of Ecological Communities

The American Naturalist, Год журнала: 1997, Номер 150(5), С. 519 - 553

Опубликована: Ноя. 1, 1997

Harsh conditions (e.g., mortality and stress) reduce population growth rates directly; secondarily, they may the intensity of interactions between organisms. Near-exclusive focus on secondary effect these forms harshness has led ecologists to believe that importance ecological interactions, such as competition, favor coexistence even ecologically very similar species. By examining both costs benefits, we show alone does not lessen species or limit their role in community structure. Species requires niche differences, itself make more likely. Fluctuations environmental disturbance, seasonal change, weather variation) also have been regarded decreasing favoring coexistence, but argue can only be favored when fluctuations create spatial temporal opportunities. We important diversity-promoting roles for harsh fluctuating depend deviations from assumptions additive effects linear dependencies most commonly found models. Such considerations imply strong diversity a community.

Язык: Английский

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How to make more out of community data? A conceptual framework and its implementation as models and software

Ecology Letters, Год журнала: 2017, Номер 20(5), С. 561 - 576

Опубликована: Март 20, 2017

Abstract Community ecology aims to understand what factors determine the assembly and dynamics of species assemblages at different spatiotemporal scales. To facilitate integration between conceptual statistical approaches in community ecology, we propose Hierarchical Modelling Species Communities ( HMSC ) as a general, flexible framework for modern analysis data. While non‐manipulative data allow only correlative not causal inference, this facilitates formulation data‐driven hypotheses regarding processes that structure communities. We model environmental filtering by variation covariation responses individual characteristics their environment, with potential contingencies on traits phylogenetic relationships. capture biotic rules species‐to‐species association matrices, which may be estimated multiple spatial or temporal operationalise hierarchical Bayesian joint distribution model, implement it R‐ Matlab‐packages enable computationally efficient analyses large sets. Armed tool, ecologists can make sense many types data, including spatially explicit time‐series illustrate use through series diverse ecological examples.

Язык: Английский

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Community assembly and invasion: An experimental test of neutral versus niche processes

Proceedings of the National Academy of Sciences, Год журнала: 2003, Номер 100(15), С. 8916 - 8920

Опубликована: Июль 3, 2003

A species-addition experiment showed that prairie grasslands have a structured, nonneutral assembly process in which resident species inhibit, via resource consumption, the establishment and growth of with similar use patterns success invaders decreases as diversity increases. In our experiment, each four functional guilds were introduced, seed, into 147 prairie–grassland plots previously had been established maintained to different compositions diversities. Established most strongly inhibited introduced from their own guild. Introduced attained lower abundances when functionally abundant left levels resources unconsumed, occurred at richness. Residents C4 grass guild, dominant guild nearby native grasslands, reduced major limiting resource, soil nitrate, lowest midsummer exhibited greatest inhibitory effect on species. This simple mechanism greater competitive inhibition are could, theory, explain many observed plant communities.

Язык: Английский

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