Plant species and assemblages show distinct geographical distribution patterns. In my research I attempt to discern the biotic and abiotic factors as well as evolutionary processes determining these patterns, especially in the tropics. Specific research topics include:

• Fern flora of Bolivia (with A.R. Smith, Berkeley, CA, USA).
• Systematics and biogeography of Andean Acanthaceae, Araceae, Bromeliaceae, Cactaceae, and Palmae.
• Ecology and biogeography of ferns in Costa Rica, Ecuador, Bolivia, Africa and the Mascarene Islands, Indonesia, and the Philippines.
• Causes determining the lower elevational limits of plants in mountains.
• Causes determining the upper timberline. 
• Tropical deciduous forest ecology.
• GIS modelling of the relationship of plant distributions and climate.
• Influence of plant species richness on ecosystem function and stability.

• Transcriptome-wide SNPs for Botrychium lunaria ferns enable fine-grained analysis of ploidy and population structure
  Mossion, Vinciane; Dauphin, Benjamin; Grant, Jason; Kessler, Michael; Zemp, Niklaus; Croll, Daniel
  Molecular Ecology Resources 10.1111/1755-0998.13478  JAN 2022
• Putting vascular epiphytes on the traits map
  Hietz, Peter; Wagner, Katrin; Ramos, Flavio Nunes; Sarmento Cabral, Juliano; Agudelo, Claudia; et al.
  Journal Of Ecology 10.1111/1365-2745.13802  NOV 2021
• Nowhere to escape - Diversity and community composition of ferns and lycophytes on the highest mountain in Honduras
  Reyes-Chavez, Johan; Quail, Megan; Tarvin, Stephanie; Kessler, Michael; Batke, Sven P.
  Journal Of Tropical Ecology 10.1017/S0266467421000122  MAR 2021
• Patterns and drivers of phylogenetic structure of pteridophytes in China
  Qian, Hong; Kessler, Michael; Deng, Tao; Jin, Yi
  Global Ecology And Biogeography 10.1111/geb.13349  SEP 2021
• The Taxonomic Distribution of Chlorophyllous Spores in Ferns: An Update
  Mellado-Mansilla, Daniela; Zotz, Gerhard; Kreft, Holger; Sundue, Michael; Kessler, Michael
  American Fern Journal 111(2): 150-156  APR-JUN 2021
• sPlotOpen - An environmentally balanced, open-access, global dataset of vegetation plots
  Sabatini, Francesco Maria; Lenoir, Jonathan; Hattab, Tarek; Arnst, Elise Aimee; Chytry, Milan; et al.
  Global Ecology And Biogeography 10.1111/geb.13346  SEP 2021
• Limited protection and ongoing loss of tropical cloud forest biodiversity and ecosystems worldwide
  Karger, Dirk Nikolaus; Kessler, Michael; Lehnert, Marcus; Jetz, Walter
  Nature Ecology & Evolution 10.1038/s41559-021-01450-y  JUN 2021
• EpiList 1.0: a global checklist of vascular epiphytes
  Zotz, Gerhard; Weigelt, Patrick; Kessler, Michael; Kreft, Holger; Taylor, Amanda
  Ecology  10.1002/ecy.3326   Early Access: APR 2021
• Global patterns and drivers of alpine plant species richness
  Testolin, Riccardo; Attorre, Fabio; Borchardt, Peter; Brand, Robert F.; Bruelheide, Helge; et al.
  Global Ecology And Biogeography  10.1111/geb.13297 Published: JUN 2021
• Functional Diversity in Ferns Is Driven by Species Richness Rather Than by Environmental Constraints
  Aros-Mualin, Daniela; Noben, Sarah; Karger, Dirk N.; Carvajal-Hernandez, Cesar I.; Salazar, Laura; et al.
  Frontiers In Plant Science 10.3389/fpls.2020.615723 JAN 11 2021
• New Guinea has the world's richest island flora
  Camara-Leret, Rodrigo; Frodin, David G.; Adema, Frits; Anderson, Christiane; Appelhans, Marc S.; et al.
  Nature  DOI: 10.1038/s41586-020-2549-5  AUG 27 2020
• Taxonomic revaluation of the Polylepis pauta and P. sericea (Rosaceae) from Ecuador
  Espinoza, Tatiana Erika Boza; Romoleroux, Katya; Kessler, Michael
  Phytotaxa  DOI: 10.11646/phytotaxa.454.2.3    JUL 29 2020
• Diversity of epiphyte ferns along an elevational gradient in El Triunfo Biosphere Reserve, southern Mexico (vol 153, pg 12, 2020)
  Jimenez-Lopez, Derio A.; Martinez-Camilo, Ruben; Martinez-Melendez, Nayely; Kessler, Michael
  Plant Ecology And Evolution   DOI: 10.5091/plecevo.2020.1759    JUL 2020
• Different Predictors Shape the Diversity Patterns of Epiphytic and Non-epiphytic Liverworts in Montane Forests of Uganda
  Maul, Karola; Wei, Yu-Mei; Nebel, Martin; Luebert, Federico; Ho, Boon-Chuan; et al.
  Frontiers In Plant Science  DOI: 10.3389/fpls.2020.00765   JUN 24 2020
• Shifts in food plant abundance for flower-visiting insects between 1900 and 2017 in the canton of Zurich, Switzerland
  Abrahamczyk, Stefan; Wohlgemuth, Thomas; Nobis, Michael; Nyffeler, Reto; Kessler, Michael
  Ecological Applications  10.1002/eap.2138  SEP 2020
• The role of hummingbirds in the evolution and diversification of Bromeliaceae: unsupported claims and untested hypotheses
  Kessler, Michael; Abrahamczyk, Stefan; Kroemer, Thorsten
  Botanical Journal Of The Linnean Society   DOI: 10.1093/botlinnean/boz100 Published: APR 2020
• Spore dispersal of Selaginella denticulate, S. helvetica, and S. selaginoides, and the significance of heterospory in Selaginellacae
  Schneller, Jakob; Kessler, Michael
  American Fern Journal  DOI: 10.1640/0002-8444-110.2.58  Published: APR-JUN 2020
• Latitudinal patterns of species richness and range size of ferns along elevational gradients at the transition from tropics to subtropics
  Hernandez-Rojas, Adriana C.; Kluge, Juergen; Kroemer, Thorsten; Carvajal-Hernandez, Cesar; Silva-Mijangos, Libertad; et al.
  Journal of Biogeography  DOI: 10.1111/jbi.13841 Early Access: APR 2020
• EpIG-DB: A database of vascular epiphyte assemblages in the Neotropics
  Mendieta-Leiva, Glenda; Ramos, Flavio N.; Elias, Joao P. C.; Zotz, Gerhard; Acuna-Tarazona, Margoth; et al.
  Journal Of Vegetation Science 31(3): 518-528, DOI: 10.1111/jvs.12867 Published: MAY 2020
• Shifts in food plant abundance for flower-visiting insects between 1900 and 2017 in the canton of Zurich, Switzerland
  Stefan Abrahamczyk, Thomas Wohlgemuth, Michael Nobis, Reto Nyffeler, Michael Kessler
  Ecological Applications, 23 April 2020. DOI: 10.1002/eap.2138
• Diversity of epiphyte ferns along an elevational gradient in El Triunfo Biosphere Reserve, southern Mexico
  Jimenez-Lopez, Derio A.; Martinez-Camilo, Ruben; Martinez-Melendez, Nayely; Kessler, Michael
  Plant Ecology And Evolution   DOI: 10.5091/plecevo.2020.1573  Published: MAR 2020
• Diatom Species Richness in Swiss Springs Increases with Habitat Complexity and Elevation
  Taxboeck, Lukas; Karger, Dirk Nikolaus; Kessler, Michael; Spitale, Daniel; Cantonati, Marco
  Water  DOI: 10.3390/w12020449  Published: FEB 2020
• The Central Andes of Peru: a key area for the conservation of Polylepis forest biodiversity
  Quispe-Melgar, Harold Rusbelth; Sevillano-Rios, C. Steven; Navarro Romo, Wendy Carolay; Ames-Martinez, Fressia Nathalie; Camel, Vladimir; et al.
  Journal Of Ornithology 161(1): 217-228, DOI: 10.1007/s10336-019-01703-5, JAN 2020
• Slowly but surely: gradual diversification and phenotypic evolution in the hyper-diverse tree fern family Cyatheaceae
  Loiseau, Oriane; Weigand, Anna; Noben, Sarah; Rolland, Jonathan; Silvestro, Daniele; et al.
  Annals Of Botany  DOI: 10.1093/aob/mcz145 Published: JAN 2 2020
• Using dendrochronology to trace the impact of the hemiparasite Tristerix chodatianus on Andean Polylepis trees
  Camel, V; Arizapana-Almonacid, M; Pyles, M; Galeano, E; Quispe-Melgar, HR; Ninanya-Parra, Z; Ames-Martinez, FN; Requena-Rojas, E; Kessler, M
  PLANT ECOLOGY, 220 (9):873-886; 10.1007/s11258-019-00961-w SEP 2019
• …

• Plant taxonomy
• Community ecology
• Plant autecology
• Macroecology
• Conservation ecology
• Tropical ecology

• Plant-animal interactions
• Pollination biology
• Species distribution modelling
• Biodiversity functionality
• Evolutionary ecology