Spatial Interaction Ecology

Welcome to the Spatial Interaction Ecology Research Group!
The research group Spatial Interaction Ecology strives to understand how human mediated environmental changes are influencing plant population dynamics, plant-animal interactions and community patterns at multiple spatial scales. In particular, we focus on the causes and consequences of exotic plant invasions, the role of human perturbations on plant-pollinator interactions and pollen limitation, the restoration of degraded habitats, and forest community dynamics.

Rainforest in Fiji
Photo by Kati Kietzmann

Causes and consequences of exotic plant invasions

Field site Hawaii Photo by Tiffany Knight
Why are some exotic plant species able to become dominant in a local plant community while others remain minor constituents? This is an important but difficult area of research in ecology. To date, research presents mixed and contradictory results of the relationship between phylogenetic novelty and invasiveness. We hope to resolve some of this variation with a synthetic approach that considers the spatial scale of the analysis and the stage of invasion.

How do biotic resistance (competition), enemy release and habitat disturbances influence the success of exotic plant species? We address this by conducting field experiments that examine multiple mechanisms of invasion and their interactions on exotic plant population dynamics. In addition, we are synthesizing the effects that natural enemy introductions have on the fitness and population dynamics of exotic weeds.

What determines the commonness and rarity of plants in island ecosystems? We address this question with a detailed case study in Hawaii on the functional traits and community composition of plants at multiple spatial scales and with a global analysis on the relative abundances of plants at local scales in island ecosystems.
 

Plant-pollinator
Photo by Christian Müller

Role of human perturbations on plant-pollinator interactions and pollen limitation

Pollen limitation occurs when plants produce fewer fruits and/or seeds than they would with an adequate receipt of pollen. Our research aims to understand the drivers of pollen limitation on a global scale by correlating the results of pollen supplementation experiments with plant traits, pollination syndromes and environmental factors. In addition, our research will address the likely consequences for pollen limitation for plant population and community dynamics and for mating system evolution.

How have human changes to the environment influenced the stability of plant-pollinator networks? Our research addresses this by examining how exotic plant introductions influence network structure. Further, we examine how climate and land use change influence plant-pollinator networks over long time periods by using historic data collected by naturalists in the late 1800s.
 

Dunes
Photo by Tiffany Knight

Restoration of degraded habitats

How can we optimize our restoration efforts to increase the abundance and diversity of native species? Our research in restoration involves 1) two long-term experiments on community assembly of prairie and glade ecosystems in St. Louis, Missouri, 2) examining the effects of large-scale habitat restoration on the endangered plant, Lupinus tidestromii, in California, 3) synthesizing the effects of coastal sand dune restoration projects on the population dynamics of rare plant species and the composition of plant communities, and 4) quantifying at the optimal timing of reintroducing fire to fire-suppressed ecosystems.
 

Hut Fiji
Photo by Tiffany Knight

Forest community dynamics

Forest ecosystems have economic and cultural value, and provide vital ecosystem services. We contribute to global efforts to understand the macroecological patterns of tree species, and assess the threat to these species, in collaboration with Botanical Garden Conservation International and the Chicago Botanic Garden. Our first site for this research is a case study in the diverse country of Fiji.
 

The SIE working group on their retreat in Nov 2016

Prof. Tiffany Knight
Alexander von Humboldt Professorship Spatial Interaction Ecology
phone +49 341 9733198
fax +49 341 9739360
E-mail Tiffany.Knight@idiv.de


Kati Kietzmann
Assistant Spatial Interaction Ecology
phone +49 341 9733198
fax +49 341 9739360
E-mail Kati.Kietzmann@idiv.de


Nina Becker
Scientific Manager
phone +49 341 9733159
fax +49 341 9739360
E-mail Nina.Becker@idiv.de


Valentin Stefan
Scientific Programmer
phone +49 341 9733210
E-mail Valentin.Stefan@idiv.de


Dr. Masha van der Sande
Research Officer - PostDoc
phone +49 341 9733117
E-mail Masha.Vandersande@idiv.de

Dr. Dylan Craven
Research Officer - PostDoc
phone +49 341 9733117
E-mail Dylan.Craven@idiv.de


Sarah Passonneau
Research Officer for bibliometrics, bibliographic management and research in ecology
phone +49 341 9733231
E-mail Sarah.Passonneau@idiv.de

Dr. Lotte Korell
Research Officer - PostDoc
phone: +49 345 5585308
E-mail Lotte.Korell@ufz.de


Dr. Jeroen Everaars
Research Assistant
E-mail jeroen.everaars@ufz.de

Elena Motivans
Student Research Assistant
E-mail elena.motivans@idiv.de


Members from Martin Luther University:

Dr. Joanne Bennett
Research Officer - PostDoc
phone +49 341 9733155
E-mail Joanne.Bennett@idiv.de

Michael Wohlwend
Research Officer - PhD
E-mail Michael.Wohlwend@idiv.de

Sarah Passonneau
Research Officer - Library Scientist
phone +49 341 9733231
E-mail Sarah.Passonneau@idiv.de

Amibeth Thompson
Student Research Assistant
phone +49 341 9733224
E-mail Amibeth.Thompson@idiv.de

Sam Levin
Student Research Assistant
phone +49 341 9733224
E-mail Sam.Levin@idiv.de

Till Groth
Student Research Assistant
E-mail

Esther Sossai
Student Research Assistant
E-mail esther.sossai@idiv.de

Crandall, R., and T.M. Knight (2015)
Positive frequency dependence undermines the success of
restoration using historical disturbance regimes. Ecology Letters 18: 883–891.


Burkle, L.A., Marlin, J.C., and T.M. Knight (2013)
Plant-Pollinator Interactions over 120 Years: Loss of Species, Co-Occurrence and Function. Science 339: 1611-1615.


Powell, K.I., J.M. Chase, and T.M. Knight (2013)
Invasive plants have scale-dependent effects on biodiversity by altering the species-area relationship. Science 339: 316-318.


Burns, J.H., E.A. Pardini, M.R. Schutzenhofer, Y.A. Chung, K.J. Seidler, and T.M. Knight (2013)
Greater sexual reproduction contributes to differences in demography of invasive plants and their noninvasive relatives. Ecology 94: 995-1004.
 

Research Gate Profile Tiffany Knight