Species Interaction Ecology


The research group Species 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.

Our research is funded by the HGF/Helmholtz Recruitment Initiative and the Alexander von Humboldt Professorship.

SIE Title

Causes and consequences of exotic plant invasions
Field site Hawaii Photo: T. Knight


Why are some exotic plant species able to become dominant in a community while others remain minor constituents? To date, research presents mixed and contradictory results of the relationship between phylogenetic novelty and invasiveness. We aim to resolve some of this variation with a synthetic approach that explicitly considers spatial scale, environmental gradients and stage of invasion. We conduct 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.

Projects:

  • Community assembly and macroecology of islands
  • Role of functional traits in explaining highly invaded Hawaiian ecosystems
  • Synthesis of biocontrol agent effects on focal and non-target plants


Pollination Ecology
Plant-pollinator Photo: C. Müller


Recent global reports such as the IPBES have documented that pollinators are declining in abundance and diversity at local, regional, and global spatial scales due to human changes to the landscapes. How will these pollinator declines change the structure of plant-pollinator interactions and the function of pollination?

We collect plant-pollinator network data and conduct pollination experiments in grassland ecosystems along elevation, latitudinal and land use gradients. We have developed collaborations in understudied regions of Europe that have high densities of traditionally managed meadows. We use hands-on summer schools to grow our database while training the next generation of pollination ecologists. We synthesize the causes and consequence of pollen limitation for plant species. We examine the history of science for this rapidly changing field of study.

Projects:

Restoration of degraded habitats
Dunes Photo: T. Knight

Grassland and coastal ecosystems provide valuable ecosystem services, including large contributions to global biogeochemical cycles and flood mitigation. However, many of these ecosystems have become heavily degraded by human activities. We examine the effects of habitat size, shape, exotic plant invasions, and dispersal limitation on plant community assembly. We study how to best optimize our monitoring efforts to identify at-risk species and their threats. We study the responses of rare plant species to large-scale habitat restoration.

Projects:

  • Experimental restoration of grassland ecosystems
  • How do we prioritize species for conservation?
  • Restoration of coastal sand dunes


Climate Change

GCEF Photo: Tricklabor


Present and future climate change is a major driver of change in world´s ecosystems. How will changes in temperature and precipitation influence plant demography and population dynamics and plant biodiversity?

Projects:

  • Effects of climate change on plant population dynamics and biodiversity
  • Range limits and demography of Carpobrotus edulis
  • Effects of climate change on plant demography in the Global Change Experimental Facility ( GCEF )


We are synthesizing the state of our knowledge on how climate change effects plant populations using COMPADRE , a global database of plant matrix models and in collaboration with the sApropos working group.
We are synthesizing the state of our knowledge on how climate change effects plant biodiversity using studies that experimentally manipulate temperature and precipitation. Further, we have initiated our own research to fill in gaps in our knowledge for certain plant species and regions of the world.

Forest community dynamics
Hut Fiji Photo: T. Knight


Forest ecosystems have economic and cultural value, and provide vital ecosystem services. The loss of forests in developing countries is a globally recognized environmental crisis. There is an urgent need to synthesize the state of our knowledge on patterns of tree species distributions and their threats.

We contribute to global efforts to understand the macroecological patterns of tree species, and assess the threat to these species. We collaborate with the Foundation for Ecological Security (FES) in India to identify important tree species, model their species distribution and assess threats to their populations by collecting demographic data.

Projects:

  • Global tree synthesis
  • India tree distributions and demography

Spatial Interaction Ecology

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

Anne-Kathrin Thomas
Assistant
phone +49 341 9733198
fax +49 341 9739360
E-mail anne-kathrin.thomas@idiv.de

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

Valentin Stefan
Research Officer
phone +49 341 9733112        
E-mail valentin.stefan@idiv.de

Dr Roxanne Leberger
Scientific Programmer
phone: +49 341 9733112
E-mail roxanne.leberger@ufz.de

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

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

Dr Demetra Rakosy
Research Officer - Postdoc
phone: +49 341 9733117
E-mail demetra.rakosy@ufz.de

Dr Bettina Ohse
Research Officer - Postdoc
E-mail bettina.ohse@ufz.de


Dr Aldo Compagnoni
Research Officer - Postdoc
phone +49 341 9739143
E-mail

Elena Motivans (on leave)
Research Officer - PhD
phone: +49 341 9739144
E-mail elena.motivans@ufz.de

Jaya Upadhyay
Research Officer - PhD
phone: +49 341 9739144
E-mail jaya.upadhyay@ufz.de

Sanne Evers
Research Officer - PhD
phone: +49 341 9733283
E-mail sanne.evers@ufz.de

Martin Andrzejak
Research Officer - PhD
phone: +49 341 9733188
E-mail martin.andrzejak@ufz.de

Saneesh Cherapurath Soman
Research Officer - PhD
phone: +49 341 9733188
E-mail saneesh.cherapurath_soman@idiv.de

Jared Cobain
Scientific Research Assistant
E-mail jared.cobain@ufz.de

Emil Cyranka
Scientific Research Assistant
E-mail emil.cyranka@ufz.de



Members of the Martin Luther University Halle-Wittenberg:

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

Henriette Morgenroth
Scientific Research Assistant
E-mail henriette.morgenroth@idiv.de


Guests

Rafael Pinheiro (FAPESP Scholarshipholder)

Malika Nisal Ratnayake (Green Talents Scholarshipholder)



Former team members:

Leana Zoller

Amibeth Thompson

Sam Levin

Neeraja Venkataraman

Eleonore Slabbert

Michael Wohlwend

Dr. Joanne Bennett

Dr. Jeroen Everaars

Dr. Dylan Craven

Dr. Masha van der Sande

Index:

You could use our publication index for further requests.

2025 (10)

  • Andrzejak, M., Knight, T.M., Plos, C., Korell, L. (2025):
    Changes in reproduction mediate the effects of climate change and grassland management on plant population dynamics
    Ecol. Appl. 35 (1), e3063 10.1002/eap.3063
  • Borer, E.T., Slette, P., Wilfahrt, P., Asmus, A., Lind, E., O'Halloran, A., Porath-Krause, A., Adler, P.B., Akasaka, M., Alberti, J., Anderson, T., Bahamonde, H., Bakker, J.D., Bakker, L., Biederman, L., Blumenthal, D., Boughton, E., Brown, C., Brudvig, L., Buckley, Y., Cadotte, M., Carbutt, C., Catford, J.A., Chaneton, E., Chu, C., Collins, S., Cottingham, K., Daleo, P., Damschen, E., D'Antonio, C., Davies, K., Dickson, T., Donohue, I., Du, G., DuPre, M., Dwyer, J., Ebeling, A., Eisenhauer, N., Eskelinen, A., Fay, P., Firn, J., Gruner, D., Güsewell, S., Hagenah, N., Haider, S., Hallett, L., Harpole, W.S., Hautier, Y., Hector, A., HilleRisLambers, J., Hillebrand, H., Hofmockel, K., Jamiyansharav, K., Jentsch, A., Kay, A., Kirkman, K., Klein, J., Knapp, A., Knight, T., Knops, J.M.H., Koerner, S., Komatsu, K., Ladwig, L., Lekberg, Y., Li, Q., Li, W., Lkhagva, A., MacDougall, A.S., Martina, J.P., Martinson, H.M., McCulley, R., Melbourne, B., Mitchell, C., Mitchell, R., Moore, J., Morgan, J., Mortensen, B., Nelson, J., Ochoa Hueso, R., Ohlert, T., Orr, D., Orrock, J., Paper, J., Peri, P.L., Pichon, N., Power, S.A., Price, J., Prober, S.M., Ren, Z., Richards, A., Risch, A.C., Roscher, C., Sankaran, M., Schuetz, M., Smith, M., Smith, N.G., Speziale, K., Spohn, M., Standish, R., Stevens, C.J., Sullivan, L., Tedder, M.J., Tognetti, P., Veen, G., Virtanen, R., Wallace, A., Wardle, G.M., Wedin, D., Weiss, A., Wheeler, G., Wolkovich, E., Wragg, P., Wright, J., Yahdjian, L., Yang, L., Yost, J., Young, A.L., Young, H., Zhang, P., Seabloom, E.W. (2025):
    Species cover, community biomass, and richness in global grasslands from NutNet (2007–2023): Dominant species predict plant richness and biomass in global grasslands ver 4
    EDI Data Portal 10.6073/pasta/442895326274ea09942bd04e6ea92df2
  • Lanuza, J.B., Knight, T.M., Montes-Perez, N., Glenny, W.R., Acuña, P., Albrecht, M., Artamendi, M., Badenhausser, I., Bennett, J.M., Biella, P., Bommarco, R., Cappellari, A., Castro, S., Clough, Y., Colom, P., Costa, J., Cyrille, N., de Manincor, N., Dominguez-Lapido, P., Dominik, C., Dupont, Y.L, Feldmann, R., Felten, E., Ferrero, V., Fiordaliso, W., Fisogni, A., FitzPatrick, Ú., Galloni, M., Gaspar, H., Gazzea, E., Goia, I., Gómez-Martínez, C., González-Estévez, M.A., González-Varo, J.P., Grass, I., Hadrava, J., Hautekèete, N., Hederström, V., Heleno, R., Hervias-Parejo, S., Heuschele, J.M., Hoiss, B., Holzschuh, A., Hopfenmüller, S., Iriondo, J.M., Jauker, B., Jauker, F., Jersáková, J., Kallnik, K., Karise, R., Kleijn, D., Klotz, S., Krausl, T., Kühn, E., Lara-Romero, C., Larkin, M., Laurent, E., Lázaro, A., Librán-Embid, F., Liu, Y., Lopes, S., López-Núñez, F., Loureiro, J., Magrach, A., Mänd, M., Marini, L., Beltran Mas, R., Massol, F., Maurer, C., Michez, D., Molina, F.P., Morente-López, J., Mullen, S., Nakas, G., Neuenkamp, L., Nowak, A., O'Connor, C.J., O'Rourke, A., Öckinger, E., Olesen, J.M., Opedal, Ø.H., Petanidou, T., Piquot, Y., Potts, S.G., Power, E.F., Proesmans, W., Rakosy, D., Reverté, S., Roberts, S.P.M., Rundlöf, M., Russo, L., Schatz, B., Scheper, J., Schweiger, O., Serra, P.E., Siopa, C., Smith, H.G., Stanley, D., Ştefan, V., Steffan-Dewenter, I., Stout, J.C., Sutter, L., Motivans Švara, E., Świerszcz, S., Thompson, A., Traveset, A., Trefflich, A., Tropek, R., Tscharntke, T., Vanbergen, A.J., Vilà, M., Vujić, A., White, C., Wickens, J.B., Wickens, V.B., Winsa, M., Zoller, L., Bartomeus, I. (2025):
    EuPPollNet: a European database of plant-pollinator networks
    Glob. Ecol. Biogeogr. 34 (2), e70000 10.1111/geb.70000
  • Lanuza, J.B., Knight, T.M., Montes-Perez, N., Glenny, W.R., Acuña, P., Albrecht, M., Artamendi, M., Badenhausser, I., Bennett, J.M., Biella, P., Bommarco, R., Cappellari, A., Castro, S., Clough, Y., Colom, P., Costa, J., Cyrille, N., de Manincor, N., Dominguez-Lapido, P., Dominik, C., Dupont, Y.L, Feldmann, R., Felten, E., Ferrero, V., Fiordaliso, W., Fisogni, A., FitzPatrick, Ú., Galloni, M., Gaspar, H., Gazzea, E., Goia, I., Gómez-Martínez, C., González-Estévez, M.A., González-Varo, J.P., Grass, I., Hadrava, J., Hautekèete, N., Hederström, V., Heleno, R., Hervias-Parejo, S., Heuschele, J.M., Hoiss, B., Holzschuh, A., Hopfenmüller, S., Iriondo, J.M., Jauker, B., Jauker, F., Jersáková, J., Kallnik, K., Karise, R., Kleijn, D., Klotz, S., Krausl, T., Kühn, E., Lara-Romero, C., Larkin, M., Laurent, E., Lázaro, A., Librán-Embid, F., Liu, Y., Lopes, S., López-Núñez, F., Loureiro, J., Magrach, A., Mänd, M., Marini, L., Beltran Mas, R., Massol, F., Maurer, C., Michez, D., Molina, F.P., Morente-López, J., Mullen, S., Nakas, G., Neuenkamp, L., Nowak, A., O'Connor, C.J., O'Rourke, A., Öckinger, E., Olesen, J.M., Opedal, Ø.H., Petanidou, T., Piquot, Y., Potts, S.G., Power, E.F., Proesmans, W., Rakosy, D., Reverté, S., Roberts, S.P.M., Rundlöf, M., Russo, L., Schatz, B., Scheper, J., Schweiger, O., Serra, P.E., Siopa, C., Smith, H.G., Stanley, D., Ştefan, V., Steffan-Dewenter, I., Stout, J.C., Sutter, L., Motivans Švara, E., Świerszcz, S., Thompson, A., Traveset, A., Trefflich, A., Tropek, R., Tscharntke, T., Vanbergen, A.J., Vilà, M., Vujić, A., White, C., Wickens, J.B., Wickens, V.B., Winsa, M., Zoller, L., Bartomeus, I. (2025):
    Correction to EuPPollNet: a European database of plant-pollinator networks
    Glob. Ecol. Biogeogr. 34 (3), e70014 10.1111/geb.70000
  • Lanuza, J.B., Knight, T., Montes-Perez, N., Glenny, W.R., Bartomeus, I. (2025):
    JoseBSL/EuPPollNet: EuPPollNet: A European database of plant-pollinator networks (v1.2.0)
    Zenodo 10.5281/zenodo.14747448
  • Rönnfeldt, A., Holle, V., Schifferle, K., Gallien, L., Knight, T., Weigelt, P., Craven, D., Cabral, J.S., Zurell, D. (2025):
    Climatic niche conservatism in non-native plants depends on introduction history and biogeographic context
    bioRxiv 10.1101/2025.01.28.635214
  • Stark, T., Wurm, M., Ştefan, V., Wolf, F., Taubenböck, H., Knight, T.M. (2025):
    Utilizing CNNs for classification and uncertainty quantification for 15 families of European fly pollinators
    bioRxiv 10.1101/2025.04.22.649975
  • Ştefan, V., Workman, A., Cobain, J.C., Rakosy, D., Knight, T.M. (2025):
    Utilising affordable smartphones and open-source time-lapse photography for pollinator image collection and annotation
    Journal of Pollination Ecology 10.26786/1920-7603(2025)778
  • Westerband, A.C., Knight, T.M., Barton, K.E. (2025):
    Scale-dependent variation in leaf functional traits clarifies mechanisms of invasion
    Ecography 10.1111/ecog.07566
  • Westerband, A.C., Knight, T.M., Barton, K.E. (2025):
    Scale-dependent variation in leaf functional traits clarifies mechanisms of invasion [Dataset]
    Dryad 10.5061/dryad.q83bk3jtj
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2024 (18)

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2023 (14)

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2022 (11)

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2021 (24)

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2020 (18)

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2019 (14)

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2018 (10)

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2017 (5)

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2016 (2)

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2015

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

2013

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