G. David Tilman

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G. David Tilman
David Tilman Royal Society.jpg
Tilman in 2017
Born
George David Titman

(1949-07-22) July 22, 1949 (age 75)
Alma mater University of Michigan
Awards
Scientific career
Institutions University of Minnesota
University of California, Santa Barbara
Thesis Interspecific competition for resources: An experimental and theoretical study  (1976)
Doctoral students
Website cbs.umn.edu/contacts/g-david-tilman

George David Tilman [2] (born Titman; [3] July 22, 1949), ForMemRS , is an American ecologist. He is Regents Professor and McKnight Presidential Chair in Ecology at the University of Minnesota, as well as an instructor in Conservation Biology; Ecology, Evolution, and Behavior; and Microbial Ecology. He is director of the Cedar Creek Ecosystem Science Reserve long-term ecological research station. Tilman is also a professor at University of California, Santa Barbara's Bren School of Environmental Science & Management. [4] [5]

Contents

Early life and education

Tilman (born Titman) [3] was born in Aurora, Illinois in 1949. He earned his Bachelor of Science degree in zoology in 1971 and his PhD in ecology in 1976 at the University of Michigan. [6] [3] Some of his doctoral research was published in the journal Science . [7]

Career and research

In an August 2001 interview, Tilman states that his passion with ecology stems from his love for both math and biology, and ecology is a field that allows him to express both together along with his love for the outdoors. [8] His work explores how both natural and managed ecosystems can be used to meet the needs of humans, whether it be for food, energy, or ecosystem services. Tilman has performed several studies to further determine the usefulness of grasslands for utilization in biofuel. [5]

Resource competition

Tilman is best known for his work on the role of resource competition in community structure and on the role of biodiversity in ecosystem functioning. [2] One of his most cited articles is the 1994 Nature article on the Biodiversity and stability in grasslands which provided data regarding an experiment that began in 1982 with more than 200 plots in a grassland field in the Cedar Creek Ecosystem Science Reserve in Minnesota. [9] Each of these plots was continuously monitored for 20 years for factors such as species richness and biomass created by the community. Tilman's article looked at data both prior to and following a drought on the grassland plots in 1988, which provided surprising results. The drought provided substantial disturbance and the biomass data showed a strong positive correlation between the plant diversity within the community and the stability of the community as a whole supporting the diversity-stability hypothesis. [10]

"The level to which the soil solution concentration of a limiting resource is reduced by an equilibrial monoculture of a species is called R*. R* is the resource concentration a species requires for it to be able to persist in a habitat. A comparable concept, that of threshold density, exists for host-microparasite inter-actions. The species with the lowest R* for a limiting soil resource is predicted to be the superior competitor for that resource." [10]

With regards to succession he focuses on resource ratios, particularly between light and nitrogen. After a big disturbance, the pattern of succession is from high light/low nitrogen towards high nitrogen/low light environment. [11]

Competition and biodiversity

Another article by Tilman that has received substantial citation [12] is his 1994 Ecology article that encompasses the idea that large numbers of species can coexist in a small habitat even when they require the same limiting nutrient (such as nitrogen), as long as there is a tradeoff between the species. Basically it means that they can coexist because species that are good competitors are not as good at colonizing or reproducing. [8] [12] In a related paper, Tilman used this model to demonstrate the phenomenon of "extinction debt," which refers to the time delay between habitat destruction and the extinction of species. [13]

Awards and honors

In 2014, he received the BBVA Foundation Frontiers of Knowledge Award in the Ecology and Conservation Biology category, for scientifically establishing the value of biodiversity, quantifying, for the first time, how it contributes to make ecosystems more productive, more resilient to invasions, and more stable in the face of perturbations such as drought. [14] He has been a Guggenheim Fellow, is a Fellow of the American Association for the Advancement of Science and of the American Academy of Arts and Sciences, and is a member of the National Academy of Sciences. [6] In 2000 Tilman was designated the Most Highly Cited Environmental Scientist of the Decade by Essential Science Indicators. [6]

Related Research Articles

<span class="mw-page-title-main">Ecosystem</span> Community of living organisms together with the nonliving components of their environment

An ecosystem is a system that environments and their organisms form through their interaction. The biotic and abiotic components are linked together through nutrient cycles and energy flows.

<span class="mw-page-title-main">Ecological niche</span> Fit of a species living under specific environmental conditions

In ecology, a niche is the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors. "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts".

<span class="mw-page-title-main">Grassland</span> Area with vegetation dominated by grasses

A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.

<span class="mw-page-title-main">Conservation biology</span> Study of threats to biological diversity

Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.

This glossary of ecology is a list of definitions of terms and concepts in ecology and related fields. For more specific definitions from other glossaries related to ecology, see Glossary of biology, Glossary of evolutionary biology, and Glossary of environmental science.

<span class="mw-page-title-main">Habitat conservation</span> Management practice for protecting types of environments

Habitat conservation is a management practice that seeks to conserve, protect and restore habitats and prevent species extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology.

The diversity of species and genes in ecological communities affects the functioning of these communities. These ecological effects of biodiversity in turn are affected by both climate change through enhanced greenhouse gases, aerosols and loss of land cover, and biological diversity, causing a rapid loss of biodiversity and extinctions of species and local populations. The current rate of extinction is sometimes considered a mass extinction, with current species extinction rates on the order of 100 to 1000 times as high as in the past.

<span class="mw-page-title-main">Habitat destruction</span> Process by which a natural habitat becomes incapable of supporting its native species

Habitat destruction occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved to elsewhere or are dead, leading to a decrease in biodiversity and species numbers. Habitat destruction is in fact the leading cause of biodiversity loss and species extinction worldwide.

A functional group is merely a set of species, or collection of organisms, that share alike characteristics within a community. Ideally, the lifeforms would perform equivalent tasks based on domain forces, rather than a common ancestor or evolutionary relationship. This could potentially lead to analogous structures that overrule the possibility of homology. More specifically, these beings produce resembling effects to external factors of an inhabiting system. Due to the fact that a majority of these creatures share an ecological niche, it is practical to assume they require similar structures in order to achieve the greatest amount of fitness. This refers to such as the ability to successfully reproduce to create offspring, and furthermore sustain life by avoiding alike predators and sharing meals.

<span class="mw-page-title-main">Interspecific competition</span> Form of competition

Interspecific competition, in ecology, is a form of competition in which individuals of different species compete for the same resources in an ecosystem. This can be contrasted with mutualism, a type of symbiosis. Competition between members of the same species is called intraspecific competition.

<span class="mw-page-title-main">Community (ecology)</span> Associated populations of species in a given area

In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community, or life assemblage. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".

<span class="mw-page-title-main">Human impact on the nitrogen cycle</span>

Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation. As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N2O) mole fractions have increased from a pre-industrial value of ~270 nmol/mol to ~319 nmol/mol in 2005. Human activities account for over one-third of N2O emissions, most of which are due to the agricultural sector. This article is intended to give a brief review of the history of anthropogenic N inputs, and reported impacts of nitrogen inputs on selected terrestrial and aquatic ecosystems.

<span class="mw-page-title-main">Effects of climate change on plant biodiversity</span>

There is an ongoing decline in plant biodiversity, just like there is ongoing biodiversity loss for many other life forms. One of the causes for this decline is climate change. Environmental conditions play a key role in defining the function and geographic distributions of plants. Therefore, when environmental conditions change, this can result in changes to biodiversity. The effects of climate change on plant biodiversity can be predicted by using various models, for example bioclimatic models.

<span class="mw-page-title-main">Plant ecology</span> The study of effect of the environment on the abundance and distribution of plants

Plant ecology is a subdiscipline of ecology that studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.

In ecology, extinction debt is the future extinction of species due to events in the past. The phrases dead clade walking and survival without recovery express the same idea.

Plant strategies include mechanisms and responses plants use to reproduce, defend, survive, and compete on the landscape. The term “plant strategy” has existed in the literature since at least 1965, however multiple definitions exist. Strategies have been classified as adaptive strategies, reproductive strategies, resource allocation strategies, ecological strategies, and functional trait based strategies, to name a few. While numerous strategies exist, one underlying theme is constant: plants must make trade-offs when responding to their environment. These trade-offs and responses lay the groundwork for classifying the strategies that emerge.

<span class="mw-page-title-main">Biodiversity loss</span> Extinction of species or loss of species in a given habitat

Biodiversity loss happens when plant or animal species disappear completely from Earth (extinction) or when there is a decrease or disappearance of species in a specific area. Biodiversity loss means that there is a reduction in biological diversity in a given area. The decrease can be temporary or permanent. It is temporary if the damage that led to the loss is reversible in time, for example through ecological restoration. If this is not possible, then the decrease is permanent. The cause of most of the biodiversity loss is, generally speaking, human activities that push the planetary boundaries too far. These activities include habitat destruction and land use intensification. Further problem areas are air and water pollution, over-exploitation, invasive species and climate change.

Erika S. Zavaleta is an American professor of ecology and evolutionary biology at the University of California, Santa Cruz. Zavaleta is recognized for her research focusing on topics including plant community ecology, conservation practices for terrestrial ecosystems, and impacts of community dynamics on ecosystem functions.

Elizabeth T. Borer is an American ecologist and a professor of ecology in the College of Biological Sciences at the University of Minnesota.

<span class="mw-page-title-main">Shahid Naeem</span> American ecologist and conservation biologist

Shahid Naeem is an ecologist and conservation biologist and is a Lenfest Distinguished professor and chair in the Department of Ecology, Evolution, and Environmental Biology at Columbia University. Naeem is the author of Biodiversity, Ecosystem Functioning, and Human Well-Being, and has published over 100 scientific articles.

References

  1. 1 2 Anon (2017). "Professor David Tilman ForMemRS". royalsociety.org. London: Royal Society.
  2. 1 2 Tilman, George David (1982). Resource competition and community structure. Vol. 17. Princeton University Press. pp. 1–296. ISBN   978-0-691-08302-5. PMID   7162524.{{cite book}}: |journal= ignored (help)
  3. 1 2 3 Titman, George David (1968). Interspecific competition for resources: An experimental and theoretical study (PhD thesis). University of Michigan. OCLC   68285554. ProQuest   302806650.(subscription required)
  4. "David Tilman". UCSB Bren School of Environmental Science & Management. Retrieved March 20, 2024.
  5. 1 2 G. David Tilman publications indexed by Google Scholar OOjs UI icon edit-ltr-progressive.svg
  6. 1 2 3 Davis, T.H. (2004). "Biography of David Tilman". Proceedings of the National Academy of Sciences of the United States of America. 101 (30): 10851–10853. Bibcode:2004PNAS..10110851D. doi: 10.1073/pnas.0404605101 . PMC   503709 . PMID   15263082.
  7. Titman, George David (1976). "Ecological Competition Between Algae: Experimental Confirmation of Resource-Based Competition Theory". Science. 192 (4238): 463–465. Bibcode:1976Sci...192..463T. doi:10.1126/science.192.4238.463. ISSN   0036-8075. PMID   17731084. S2CID   30492089.
  8. 1 2 "An Interview with Dr. David Tilman". in-cites. 1991.
  9. Tilman, David; Downing, John A. (1994). "Biodiversity and stability in grasslands". Nature. 367 (6461): 363–365. Bibcode:1994Natur.367..363T. doi:10.1038/367363a0. ISSN   0028-0836. S2CID   4324145.
  10. 1 2 Tilman, David (1990). "Constraints and Tradeoffs: Toward a Predictive Theory of Competition and Succession". Oikos . 58 (1): 3–15. Bibcode:1990Oikos..58....3T. doi:10.2307/3565355. ISSN   0030-1299. JSTOR   3565355. S2CID   13924571.
  11. Bazzaz, F. A. (1996). Plants in Changing Environments. UK: Cambridge University Press. p. 16. ISBN   978-0-521-39843-5.
  12. 1 2 Tilman, David (1994). "Competition and Biodiversity in Spatially Structured Habitats" (PDF). Ecology. 75 (1): 2–16. Bibcode:1994Ecol...75....2T. doi:10.2307/1939377. JSTOR   1939377. Archived from the original (PDF) on March 3, 2016. Retrieved December 4, 2014.
  13. Tilman, D.; May, R. M.; Lehman, C. L.; Nowak, M. A. (1994). "Habitat destruction and the extinction debt". Nature. 371 (6492): 65. Bibcode:1994Natur.371...65T. doi:10.1038/371065a0. S2CID   4308409.
  14. "BBVA Foundation Frontiers of Knowledge Awards". www.fbbva.es. Archived from the original on January 22, 2017. Retrieved July 4, 2016.