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Plant competitive interactions under soil nutrient transport limitation

English title Plant competitive interactions under soil nutrient transport limitation
Applicant Niklaus Pascal A.
Number 137132
Funding scheme ProDoc
Research institution Institut für Evolutionsbiologie und Umweltwissenschaften Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Ecology
Start/End 01.09.2011 - 31.12.2014
Approved amount 220'994.00
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All Disciplines (3)

Discipline
Ecology
Botany
Environmental Research

Keywords (6)

biodiversity; ecology; competition; isotope techniques; soil nutrients; modelling

Lay Summary (English)

Lead
Lay summary

A central question in plant ecology is which plant species can co-occur in a community, sharing the same set of resources. In principle, species with superior competitive abilities might displace other species by reducing resources to levels where their competitors cannot exist anymore, thereby reducing the diversity in plant communities.

Empirical evidence shows, however, that often more species than might be expected in fact coexist. It has been proposed that this is the case because even a species very efficiently acquiring a resource will not be able to reduce the availability of this resource to plant individuals that are far away. In this case, the strength with which individuals can compete will be determined by the degree to which the resource pools accessible to competing individuals (e.g. soil nutrients) are connected, i.e. the rate with which e.g. nutrients are transported between the two. When transport is strongly limited, individuals will be more separated in terms of competition for these nutrients, i.e. their coexistence will be facilitated.

To date, the e?ects of nutrient transport rates on the strength of plant competitive interactions has only been explored in mathematical models, probably because manipulations of transport limitations in "real" soils are difficult to achieve due to the multitude of ways in which nutrients move in soils. In the present project, we propose experimental manipulations of nutrient transport in experimental plant communities to test for their effects on the performance of their component individuals and on the strength of their competitive interactions. We will assess nutrient transport between individuals using isotopic and statistical approaches, and test whether the strength of their interactions correlates with measured transport rates as predicted by competition theories.

The proposed experimental manipulations and the analysis of their consequences are relevant from a basic science and an applied perspective, especially since agricultural soil management alters the mechanisms addressed in this project.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Annual Meeting, Ecological Societry of America Talk given at a conference Plant competitive interactions under soil nutrient transport limitation 11.08.2014 Sacramento, CA, United States of America Milkereit Janina; Niklaus Pascal A.;
Into the next 100 years, INTECOL 2013 and British Ecological Society Meeting Talk given at a conference What good are neighbourhood models? 19.09.2013 London, Great Britain and Northern Ireland Stoll Peter;
Exploring the trait-based functional biodiversity approach Talk given at a conference A plant perspective on diversity and traits 13.02.2013 Wageningen, Netherlands Niklaus Pascal A.;


Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Science presentation to MNF dean's office Talk 05.02.2014 Zürich, Switzerland Milkereit Janina; Niklaus Pascal A.;
Führung mit Gymnasialklasse "Biodiversitätsforschung" Performances, exhibitions (e.g. for education institutions) 05.12.2012 Zürich, Switzerland Milkereit Janina;


Communication with the public

Communication Title Media Place Year
Media relations: print media, online media UEFA Revue Western Switzerland 2015
Talks/events/exhibitions Science Info Day, University of Zürich German-speaking Switzerland 2014
Talks/events/exhibitions Scientifica German-speaking Switzerland 2013
Talks/events/exhibitions "Paradoxe Vielfalt trotz Konkurrenz" German-speaking Switzerland 2011

Associated projects

Number Title Start Funding scheme
127227 PSC "Plant Sciences and Policy" 01.11.2009 ProDoc

Abstract

Background --- A crucial question in plant ecology is how local interactions between individuals and species structure plant communities and determine their diversity. Species with superior competitive abilities might displace other species by reducing soil nutrient concentrations to levels where these cannot coexist (at least in the absence of disturbance).It has been proposed that the strength of these competitive interactions is modulated by soil nutrient transport rate; when transport is strongly limited, individuals cannot effectively lower nutrient concentrations around heterospecific neighbors, and coexistence is facilitated.Objectives --- To date, the effects of nutrient transport rates on the strength of plant competitive interactions has only been explored in mathematical models, probably because manipulations of transport limitations in "real" soils are difficult to achieve due to the multitude of modes by which nutrients move in soils (e.g. mass flow, diffusion, mycorrhizal networks).Here, we propose specific experimental manipulations of nutrient transport in experimental plant communities to test for effects on the performance of the component individuals and on the strength of their competitive interactions. We will assess nutrient transport between conspecific and heterospecific individuals and test whether the strength of their interactions correlates with measured transport rates as predicted by competition theories.Methods --- Experimental plant communities comprising of 1, 2 or 4 species will be set up and subjected to two experimental treatments: (1) a manipulation of the integration of plant communities by mycorrhizal networks; and (2) a manipulation of the mobility of applied nitrogen fertilizer using a nitrification inhibitor. Nitrogen and phosphorus transport will be quantified using stable and radio-isotopes. Competitive interactions will be analyzed at the community level by analyzing the overyielding of mixtures relative to monocultures, and at the individual level by comparing their performance under conspecific and heterospecific competition, using statistical and mechanistic, individual-based, spatially-explicit models.Expected Value --- This project addresses a hypothesis related to central concepts in ecology. The proposed interdisciplinary collaboration integrates approaches that traditionally have been pursued separately, namely the analysis of plant responses, soil processes, and model simulations. It further adopts novel experimental and methodological techniques. The proposed experiments combines a demographic focus on individuals with a focus on biogeochemical processes, promising new insights into the mechanisms maintaining biodiversity in plant communities.The proposed experimental manipulations and the analysis of their consequences also are relevant from an applied perspective. Agricultural soil management alters mycorrhizal networks, and soil nitrogen mobility is currently being manipulated at the large-scale by the increasing application of nitrification inhibitors. Outreach --- The integration in the ProDoc "Plant Sciences and Policy" will allow the PhD candidate to develop the skills required for the successful dissemination of the proposed research to relevant stakeholders. In engaging into this process, the student will benefit from the close links of our institutes to NGOs but also to federal institutions and policy makers.
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