Browsing by Subject "COMPETITION"

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Open Access
Earthworms modify plant biomass and nitrogen capture under conditions of soil nutrient heterogeneity and elevated atmospheric CO2 concentrations
(Soil Biology and Biochemistry, 2014-01-01) García-Palacios, Pablo; Maestre, Fernando T; Bradford, Mark A; Reynolds, James F
Earthworms modify the way roots respond to soil nutrient patchiness. However, few studies have evaluated the joint effects of earthworms and soil heterogeneity on plant community biomass and species dominance, and none of them have assessed the influence of different patch features and environmental conditions on such effects. We evaluated how soil nutrient heterogeneity, earthworms (Eisenia fetida), organic material quality (15N-labelled leaves and roots of contrasting C: N ratios) and elevated atmospheric CO2 concentrations (phytotron chambers) affected the resource-use strategy, biomass and species dominance of mixtures formed by Lolium perenne L. and Plantago lanceolata L. Soil heterogeneity decreased N capture from the organic material, especially in the presence of earthworms. Mixtures experienced a 26 and 36% decrease in shoot and root biomass when earthworms were added to the heterogeneous microcosms, but only with high quality organic material. The dominance of L. perenne was lower under conditions of elevated CO2, nutrient heterogeneity and earthworms. Our data suggest that earthworms can neutralize positive plant growth responses to soil heterogeneity by exacerbating decreases in the supply of N to the plant. Specifically, earthworms foraging for high quality patches may stimulate microbial N immobilization, translating into lower N capture by plants. Increases in casting activity under elevated CO2, and hence in microbial N immobilization, may also explain why earthworms modulated the effects of soil heterogeneity and CO2 concentrations on plant community structure. We show that earthworms, absent from most soil nutrient heterogeneity studies, mediate plant biomass responses to nutrient patchiness by affecting N capture. Future plant-foraging behaviour studies should consider the roles played by soil engineers such as earthworms, so that results can be better extrapolated to natural communities. © 2014 Elsevier Ltd.
Open Access
Nonstate Actors and Compliance with International Agreements: An Empirical Analysis of the OECD Anti-Bribery Convention
(International Organization, 2018) Jensen, NM; Malesky, EJ
© 2017 The IO Foundation. International relations scholarship has made great progress on the study of compliance with international agreements. While persuasive, most of this work has focused on states' de jure compliance decisions, largely excluding the de facto behavior of nonstate actors whose actions the agreement hopes to constrain. Of particular interest has been whether the OECD Anti-Bribery Convention (ABC) might reduce the propensity of multinational corporations (MNCs) to bribe officials in host countries through its mechanisms of extraterritoriality and extensive peer review. Unfortunately, research is hampered by reporting bias. Since the convention raises the probability of investors' punishment for bribery in their home countries, it reduces both the incentives for bribery and willingness to admit to the activity. This generates uncertainty over which of these incentives drives any correlation between signing the convention and reductions in reported bribery. We address this problem by employing a specialized survey experiment that shields respondents and reduces reporting bias. We find that after the onset of Phase 3 in 2010, when the risk of noncompliance increased for firms subject to the OECD-ABC, those MNCs reduced their actual bribery relative to their nonsignatory competitors.
Open Access
The Emergence of Organizational Forms: A Community Ecology Approach
(American Journal of Sociology, 2000) Ruef, M
This article introduces a new ecological approach to the study of form emergence based on the notion of an organizational community - a bounded set of forms with related identities. Applying the approach to 48 organizational forms in the health care sector, this study suggests that the development of novel forms is affected by the positioning of their identities with respect to existing form identities in the community, by the aggregate density and size of organizations matching those existing identities, and by the amount of attention directed at identity attributes by sector participants. Findings show that the process of form emergence is subject to population-dependent effects akin to those noted previously for organizational entries within established populations. The aggregate density and size of organizations with similar identities increase the probability of form emergence to a point (cross-form legitimation), but highly saturated regions of the identity space tend to be uninviting to new forms (cross-form competition).