Mechanisms of Maintenance of Species Diversity

Annual Review of Ecology and Systematics, Год журнала: 2000, Номер 31(1), С. 343 - 366

Опубликована: Ноя. 1, 2000

▪ Abstract The focus of most ideas on diversity maintenance is species coexistence, which may be stable or unstable. Stable coexistence can quantified by the long-term rates at community members recover from low density. Quantification shows that mechanisms function in two major ways: They (a) equalizing because they tend to minimize average fitness differences between species, (b) stabilizing increase negative intraspecific interactions relative interspecific interactions. Stabilizing are essential for and include traditional such as resource partitioning frequency-dependent predation, well depend fluctuations population densities environmental factors space time. Equalizing contribute reduce large inequalities might negate effects mechanisms. Models unstable coexitence, slowly decays over time, have focused almost exclusively These models would more robust if also included mechanisms, arise many varied ways but need not adequate full stability a system. invite broader view incorporating turnover.

Язык: Английский

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The Dilemma of Plants: To Grow or Defend

The Quarterly Review of Biology, Год журнала: 1992, Номер 67(3), С. 283 - 335

Опубликована: Сен. 1, 1992

Physiological and ecological constraints play key roles in the evolution of plant growth patterns, especially relation to defenses against herbivores. Phenotypic life history theories are unified within growth-differentiation balance (GDB) framework, forming an integrated system explaining predicting patterns defense competitive interactions evolutionary time. Plant activity at cellular level can be classified as (cell division enlargement) differentiation (chemical morphological changes leading cell maturation specialization). The GDB hypothesis is premised upon a physiological trade-off between processes. exists because secondary metabolism structural reinforcement physiologically constrained dividing enlarging cells, they divert resources from production new leaf area. Hence dilemma plants: They must grow fast enough complete, yet maintain necessary survive presence pathogens hervivores. processes interacts with herbivory plant-plant competition manifest itself genetic strategies. Evolutionary reviewed. We also extend standard rate model by separating its components,and formalizing role defense. conclude conceptual which physioligical trade-offs interact abiotic environment, herbivory.

Язык: Английский

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Productivity and sustainability influenced by biodiversity in grassland ecosystems

Nature, Год журнала: 1996, Номер 379(6567), С. 718 - 720

Опубликована: Фев. 1, 1996

Язык: Английский

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PLANT FUNCTIONAL MARKERS CAPTURE ECOSYSTEM PROPERTIES DURING SECONDARY SUCCESSION

Ecology, Год журнала: 2004, Номер 85(9), С. 2630 - 2637

Опубликована: Сен. 1, 2004

Although the structure and composition of plant communities is known to influence functioning ecosystems, there as yet no agreement how these should be described from a functional perspective. We tested biomass ratio hypothesis, which postulates that ecosystem properties depend on species traits contribution total community, in successional sere following vineyard abandonment Mediterranean region France. Ecosystem-specific net primary productivity, litter decomposition rate, soil carbon nitrogen varied significantly with field age, correlated community-aggregated (i.e., weighed according relative abundance species) leaf traits. The three easily measurable tested, specific area, dry matter content, concentration, provide simple means scale up organ complex communities. propose they called "functional markers," used assess impacts community changes induced, particular, by global change drivers.

Язык: Английский

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None

Plant and Soil, Год журнала: 1998, Номер 199(2), С. 213 - 227

Опубликована: Янв. 1, 1998

Язык: Английский

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A REVIEW OF TRAIT-MEDIATED INDIRECT INTERACTIONS IN ECOLOGICAL COMMUNITIES

Ecology, Год журнала: 2003, Номер 84(5), С. 1083 - 1100

Опубликована: Май 1, 2003

In this paper we review the empirical studies documenting trait-mediated indirect interactions (TMIIs) in food webs. Basic models and approaches that form foundation of our conceptualization species generally assume are an intrinsic property two interacting therefore governed by their respective densities. However, if a reacts to presence second altering its phenotype, then trait changes reacting can alter per capita effect on other and, consequently, population density or fitness species. Such reinforce oppose density-mediated effects have been largely overlooked community ecologists. We first briefly develop case for broad mechanistic basis TMIIs direct evidence various permutations simple three- four-species find strong quantitatively significant variety aquatic terrestrial systems. further highlight those few address question relative magnitudes density- role densities transmission. These indicate often as stronger than effects. conclude ecological communities replete with arising from plasticity these important dynamics. Finally, synthesize results profitable directions future research. Corresponding Editor: F. R. Adler. For reprints Special Feature, see footnote 1, p. 1081.

Язык: Английский

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Biodiversity: Population Versus Ecosystem Stability

Ecology, Год журнала: 1996, Номер 77(2), С. 350 - 363

Опубликована: Март 1, 1996

The relationships between biodiversity and stability were determined for both population ecosystem traits in a long—term study of 207 grassland plots. Results demonstrate that stabilizes community processes, but not processes. Specifically, year—to—year variability total aboveground plant biomass was significantly lower plots with greater species richness the entire 11—yr period nine non—drought years. change from before drought to peak also highly dependent on richness. For all three measures stability, multiple regressions controlled covariates showed similar significant diversity stability. In contrast, abundances stabilized by either years or This difference vs. likely results interspecific competition. When climatic variations harm some species, unharmed competitors increase. Such compensatory increases stabilize biomass, cause be more variable. These support predictions Robert May concerning effects diversity—stability hypothesis as applied thus helping reconcile long—standing dispute.

Язык: Английский

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Ecology of sprouting in woody plants: the persistence niche

Trends in Ecology & Evolution, Год журнала: 2001, Номер 16(1), С. 45 - 51

Опубликована: Янв. 1, 2001

Язык: Английский

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COMMUNITY INVASIBILITY, RECRUITMENT LIMITATION, AND GRASSLAND BIODIVERSITY

Ecology, Год журнала: 1997, Номер 78(1), С. 81 - 92

Опубликована: Янв. 1, 1997

Plant species composition, abundances, and richness were strongly recruitment limited in a 4-yr experiment which seeds of up to 54 added patches native grassland. Four field seasons after one-time addition seed, many still present reproducing, with plots seeded at the highest rate having that was 83% greater total plant cover 31% than controls. Total community increased significantly number as but pre-existing independent suggesting new mainly filled previously “empty” sites. The proportion became established negatively correlated initial plots, species-rich sites more resistant invasion. Plot invasibility also depended on abundances functional groups seed size cover. major plants differed their abilities invade perennial grasses being poorest invaders herbaceous legumes best. Thus, local biotic interactions dynamics jointly determined diversity, these grassland communities. This supports metapopulation-like perspective over purely interspecific-interaction or regional perspective, limitation may be important, even scale, often recognized.

Язык: Английский

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Functional- and abundance-based mechanisms explain diversity loss due to N fertilization

Proceedings of the National Academy of Sciences, Год журнала: 2005, Номер 102(12), С. 4387 - 4392

Опубликована: Март 8, 2005

Human activities have increased N availability dramatically in terrestrial and aquatic ecosystems. Extensive research demonstrates that local plant species diversity generally declines response to nutrient enrichment, yet the mechanisms for this decline remain unclear. Based on an analysis of >900 responses from 34 N-fertilization experiments across nine ecosystems North America, we show both trait-neutral trait-based operate simultaneously influence loss as production increases. Rare were often lost because soil fertilization, randomly with respect traits. The risk due fertilization ranged >60% rarest 10% most abundant species. Perennials, N-fixing symbionts, those native origin also experienced extinction after regardless their initial abundance. Whereas abundance was consistently important all systems, functional system-dependent. As continues increase globally, management focuses locally susceptible groups rare will be essential maintain biodiversity.

Язык: Английский

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