I. Ullmann

1.0k total citations
33 papers, 701 citations indexed

About

I. Ullmann is a scholar working on Plant Science, Ecology, Evolution, Behavior and Systematics and Nature and Landscape Conservation. According to data from OpenAlex, I. Ullmann has authored 33 papers receiving a total of 701 indexed citations (citations by other indexed papers that have themselves been cited), including 27 papers in Plant Science, 14 papers in Ecology, Evolution, Behavior and Systematics and 13 papers in Nature and Landscape Conservation. Recurrent topics in I. Ullmann's work include Botany and Plant Ecology Studies (14 papers), Ecology and Vegetation Dynamics Studies (12 papers) and Lichen and fungal ecology (8 papers). I. Ullmann is often cited by papers focused on Botany and Plant Ecology Studies (14 papers), Ecology and Vegetation Dynamics Studies (12 papers) and Lichen and fungal ecology (8 papers). I. Ullmann collaborates with scholars based in Germany, United States and New Zealand. I. Ullmann's co-authors include Hansjörg Dietz, O. L. Lange, Peter Bannister, J. Bastow Wilson, Thomas Steinlein, James R. Ehleringer, I.R. Cowan, Ernst‐Detlef Schulze, H. Zellner and H. Ziegler and has published in prestigious journals such as Journal of Ecology, Oecologia and Phytochemistry.

In The Last Decade

I. Ullmann

33 papers receiving 626 citations

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name h Career Trend Papers Cites
I. Ullmann Germany 17 450 344 262 142 94 33 701
G. E. Gibbs Russell South Africa 11 390 0.9× 347 1.0× 378 1.4× 110 0.8× 70 0.7× 27 762
Rebecca W. Dolan United States 14 425 0.9× 453 1.3× 472 1.8× 205 1.4× 161 1.7× 28 867
B. P. M. Hyland Australia 10 230 0.5× 221 0.6× 222 0.8× 118 0.8× 109 1.2× 16 616
Àngel Romo Spain 19 575 1.3× 431 1.3× 349 1.3× 241 1.7× 110 1.2× 81 1.1k
Roberto Calamassi Italy 14 534 1.2× 124 0.4× 204 0.8× 123 0.9× 189 2.0× 34 785
Inderjit India 8 642 1.4× 201 0.6× 314 1.2× 138 1.0× 47 0.5× 10 866
Stephen N. Stephenson United States 6 295 0.7× 225 0.7× 201 0.8× 216 1.5× 125 1.3× 8 630
José Pires de Lemos Filho Brazil 18 331 0.7× 366 1.1× 163 0.6× 65 0.5× 76 0.8× 47 673
G. Orshan Israel 14 564 1.3× 351 1.0× 408 1.6× 157 1.1× 209 2.2× 25 896
I. H. McNaughton United Kingdom 11 434 1.0× 321 0.9× 284 1.1× 144 1.0× 61 0.6× 20 751

Countries citing papers authored by I. Ullmann

Since Specialization
Citations

This map shows the geographic impact of I. Ullmann's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by I. Ullmann with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites I. Ullmann more than expected).

Fields of papers citing papers by I. Ullmann

Since Specialization
Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by I. Ullmann. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by I. Ullmann. The network helps show where I. Ullmann may publish in the future.

Co-authorship network of co-authors of I. Ullmann

This figure shows the co-authorship network connecting the top 25 collaborators of I. Ullmann. A scholar is included among the top collaborators of I. Ullmann based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with I. Ullmann. I. Ullmann is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

20 of 20 papers shown
1.
Ullmann, I., A. Herrmann, Mario Hasler, Daguang Cai, & F. Taube. (2015). Variability in the critical phase of stem elongation of perennial ryegrass genotypes: a source for breeding progress?. The Journal of Agricultural Science. 154(6). 1002–1014. 2 indexed citations
2.
Dietz, Hansjörg, Alexander Köhler, & I. Ullmann. (2002). Regeneration growth of the invasive clonal forb Rorippa austriaca (Brassicaceae) in relation to fertilization and interspecific competition. Plant Ecology. 158(2). 171–182. 27 indexed citations
3.
Dietz, Hansjörg, Thomas Steinlein, & I. Ullmann. (1999). Establishment of the invasive perennial herb Bunias orientalis L.: An experimental approach. Acta Oecologica. 20(6). 621–632. 36 indexed citations
4.
Ullmann, I., Peter Bannister, & J. Bastow Wilson. (1998). Lateral differentiation and the role of exotic species in roadside vegetation in southern New Zealand. Flora. 193(2). 149–164. 22 indexed citations
5.
Dietz, Hansjörg, Thomas Steinlein, & I. Ullmann. (1998). The role of growth form and correlated traits in competitive ranking of six perennial ruderal plant species grown in unbalanced mixtures. Acta Oecologica. 19(1). 25–36. 25 indexed citations
6.
Beyschlag, Wolfram, et al.. (1996). Experimental Studies on the Competitive Balance between Two Central European Roadside Grasses with Different Growth Forms: 2. Controlled Experiments on the Influence of Soil Depth, Salinity and Allelopathy on Competitive Ability. Botanica Acta. 109. 449–455. 5 indexed citations
7.
Dietz, Hansjörg, Thomas Steinlein, Peter Winterhalter, & I. Ullmann. (1996). Role of allelopathy as a possible factor associated with the rising dominance ofBunias orientalis L. (Brassicaceae) in some native plant assemblages. Journal of Chemical Ecology. 22(10). 1797–1811. 14 indexed citations
8.
Wilson, J. Bastow, I. Ullmann, & Peter Bannister. (1996). Do Species Assemblages Ever Recur?. Journal of Ecology. 84(3). 471–471. 11 indexed citations
9.
Steinlein, Thomas, Hansjörg Dietz, & I. Ullmann. (1996). Growth patterns of the alien perennial Bunias orientalis L. (Brassicaceae) underlying its rising dominance in some native plant assemblages. Plant Ecology. 125(1). 73–82. 30 indexed citations
10.
Beyschlag, Wolfram, et al.. (1992). Experimental and Modelling Studies of Competition for Light in Roadside Grasses. Botanica Acta. 105(4). 285–291. 10 indexed citations
11.
Lange, O. L., Angelika Meyer, I. Ullmann, & H. Zellner. (1991). Mikroklima, Wassergehalt und Photosynthese von Flechten in der küstennahen Nebelzone der Namib-Wüste: Messungen während der herbstlichen Witterungsperiode. Flora. 185(4). 233–266. 46 indexed citations
12.
Lange, O. L., A. Meyer, H. Zellner, I. Ullmann, & Dirk Wessels. (1990). Eight days in the life of a desert lichen: water relations and photosynthesis of teloschistes capensis in the coastal fog zone of the Namib Desert. 17(1). 17–30. 28 indexed citations
13.
Ullmann, I., et al.. (1990). Conyzo-Panicetum capillaris Eine "moderne" Anthropochoren-Gesellschaft des südlichen Mitteleuropa. Phytocoenologia. 18(2-3). 371–386. 1 indexed citations
14.
15.
Ullmann, I., et al.. (1989). Geographical and Ecological Differentiation of Roadside Vegetation in Temperate Europe*. Botanica Acta. 102(4). 261–269. 42 indexed citations
16.
Ehleringer, James R., I. Ullmann, O. L. Lange, et al.. (1986). Mistletoes: a hypothesis concerning morphological and chemical avoidance of herbivory. Oecologia. 70(2). 234–237. 46 indexed citations
17.
Ullmann, I., O. L. Lange, H. Ziegler, et al.. (1985). Diurnal courses of leaf conductance and transpiration of mistletoes and their hosts in Central Australia. Oecologia. 67(4). 577–587. 98 indexed citations
18.
Kubeczka, K.–H. & I. Ullmann. (1983). Chemotypen bei Molopospermum peloponnesiacum (L.) Koch / Chem otypes o f molopospermum peloponnesiacum (L.) Koch. Zeitschrift für Naturforschung C. 38(3-4). 189–193. 3 indexed citations
19.
Ullmann, I., et al.. (1981). Terpenoids of the essential oil from Molopospermum peloponnesiacum roots. Phytochemistry. 20(4). 828–830. 16 indexed citations
20.
Ullmann, I., et al.. (1980). Occurrence of 1,5-dimethylcyclodeca-1,5,7-triene (Pregeijerene) in Pimpinella species and chemosystematic implications. Biochemical Systematics and Ecology. 8(1). 39–41. 26 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

Explore authors with similar magnitude of impact

Breakdown of academic impact, for papers by G. E. Gibbs Russell Breakdown of academic impact, for papers by Rebecca W. Dolan Breakdown of academic impact, for papers by B. P. M. Hyland Breakdown of academic impact, for papers by Àngel Romo Breakdown of academic impact, for papers by Roberto Calamassi Breakdown of academic impact, for papers by Inderjit Breakdown of academic impact, for papers by Stephen N. Stephenson Breakdown of academic impact, for papers by José Pires de Lemos Filho Breakdown of academic impact, for papers by G. Orshan Breakdown of academic impact, for papers by I. H. McNaughton
Rankless by CCL
2026