<descriptor thcode="2"><thesaurus thcode="2" name="USGS Thesaurus" scope="Topics and methods of scientific study carried out by USGS, with product types, scientific disciplines, geologic time, and types of institutional structure and activities.  Broad and shallow, used to help people find scientific information." creator="U.S. Geological Survey" rights="Public domain" edition="2.0" date="2020-01-09" codetype="number" prefix="topic" uri="https://www2.usgs.gov/science/USGSThesaurus" tblname="term" nonpref="nonpref" relterm="relterm" root_code="1" contact="pschweitzer"><category><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/></category><altlabel><altlabel>USGSThesaurus</altlabel><altlabel>USGSThesaurus</altlabel></altlabel></thesaurus><term thcode="2" code="921" name="population and community ecology" parent="1174" scope="Interactions of a single species (population) or an association of different species (community) occupying a particular region, including their biotic and abiotic environments."/><uf><usefor name="life history"/><usefor name="population energetics"/><usefor name="radar ecology"><usewith><term thcode="2" code="1727" name="doppler radar imaging" parent="948" scope="Exploitation of the doppler effect in radar imaging to determine speed of airborne objects such as birds, butterflies, and clouds."/></usewith></usefor></uf><bt><term thcode="2" code="1174" name="topics" parent="1" scope="Themes, subjects, and concerns for which USGS information resources are relevant."/><term thcode="2" code="1" name="Categories" scope="Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."/></bt><nt><term thcode="2" code="40" name="animal behavior" parent="921" scope="The way animals act or react to conditions in the environment and to other organisms, including life patterns such as migration, hibernation, and nocturnal living."/><term thcode="2" code="92" name="biodiversity" parent="921" scope="The variety in form, genetics, and ecological roles of organisms within a specific geographic area."/><term thcode="2" code="96" name="biogeography" parent="921" scope="The study of the geographic distributions of plants and animals."/><term thcode="2" code="187" name="community ecology" parent="921" scope="Study of the relationships of species that interact in a common area."/><term thcode="2" code="319" name="ecosystems" parent="921" scope="The interacting populations of plants, animals, and  microorganisms occupying a certain area, and their relationship to the environment."/><term thcode="2" code="525" name="habitats" parent="921" scope="Parts of the physical environment where plants and animals live. Use in combination with terms from organisms and organism groupings (non-taxonomic) to indicate the topic of a species or group of species habitat."/><term thcode="2" code="1796" name="phenology" parent="921" scope="Study of the response of organisms to seasonal or interannual changes in the environment."/><term thcode="2" code="922" name="population dynamics" parent="921" scope="Changes in the size, composition, or structure of aggregates of single or multiple species in a specific area over time."/><term thcode="2" code="1688" name="symbiosis" parent="921" scope="An intimate, prolonged association between two or more organisms of different species that may or may not benefit each member."/></nt><rt><term thcode="2" code="107" name="biological population management" parent="776" scope="Judicious means of controlling or directing numbers and life conditions of organisms living in a specific locality to achieve a selected goal."/><term thcode="2" code="310" name="ecological processes" parent="101" scope="Dynamic biogeochemical interactions that occur among and between biotic and abiotic components of the biosphere."/><term thcode="2" code="311" name="ecology" parent="650" scope="Study of the relations between living plants and animals and their environment."/><term thcode="2" code="317" name="ecosystem monitoring" parent="375" scope="Recording, evaluating, and actively intervening over time in the interaction of living and nonliving elements in a specific environment."/><term thcode="2" code="776" name="natural resource management" parent="689" scope="Using a combination of techniques to control or direct the use of resources and limit population size to reach a predetermined goal, such as sustainability."/><term thcode="2" code="978" name="relative abundance analysis" parent="189" scope="Determination of the percentage of individuals of one group in comparison to the total of all individuals in a given area."/></rt></descriptor>