Editing Guam (section)

=== Ecology ===
{{main|Marianas tropical dry forests}}
{{further|List of endemic plants in the Mariana Islands|List of threatened, endangered and extinct species in the Mariana Islands|Invasive species in Guam|Climate change in Guam|Guam National Wildlife Refuge}}
[[File:Ficus prolixa interwoven canopy. 1000 Steps hiking trail, Pagat, Guam.jpg|thumb|Hiking in Guam's limestone forest.]]
Guam is home to a diverse array of ecosystems,<ref>{{Cite web |title=Natural Environment - Guampedia |url=https://www.guampedia.com/category/natural-environment/ |access-date=2025-01-02 |website=www.guampedia.com}}</ref><ref>{{Cite web |last=Murphy |first=Shannon |date=2011-02-13 |title=Ancient Guam's Environment - Guampedia |url=https://www.guampedia.com/ancient-guams-environment/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> including coral reefs,<ref>{{Cite web |last=Pereda |first=Nathalie |date=2019-10-10 |title=Coral Reefs: Essential Ecosystems on Guam - Guampedia |url=https://www.guampedia.com/coral-reefs-essential-ecosystems-on-guam/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> deep seas, sea grasses,<ref>{{Cite web |last=Murphy |first=Shannon |date=2009-10-01 |title=Seagrasses Overview - Guampedia |url=https://www.guampedia.com/seagrasses-overview/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> beach strand, mangroves,<ref>{{Cite web |last=Pereda |first=Nathalie |date=2017-08-04 |title=Mangroves: The Forest Between Land and Sea - Guampedia |url=https://www.guampedia.com/mangroves-the-forest-between-land-and-sea/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> a variety of different [[Marianas tropical dry forests|limestone forest]] types,<ref>{{Cite web |last=Pereda |first=Nathalie |date=2019-10-02 |title=Limestone Forests of Guam - Guampedia |url=https://www.guampedia.com/limestone-forests-of-guam/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref><ref>{{Cite journal |last=Fosberg |first=F. Raymond |date=1960 |title=The Vegetation of Micronesia. 1, General descriptions, the vegetation of the Marianas Islands, and a detailed consideration of the vegetation of Guam |url=https://digitallibrary.amnh.org/items/b7a6abd7-e958-47d7-98aa-89efd6c2da30 |journal=Bulletin of the AMNH |volume=119 |issue=1 |via=American Museum of Natural History}}</ref> volcanic forests and grasslands,<ref>{{Cite web |last=Pereda |first=Nathalie |date=2017-08-04 |title=Badlands in Southern Guam - Guampedia |url=https://www.guampedia.com/badlands-in-southern-guam/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> [[List of rivers of Guam|riparian systems]], and caves.<ref>{{Cite web |last=Pereda |first=Nathalie |date=2019-10-02 |title=Guam's Amazing Caves - Guampedia |url=https://www.guampedia.com/guams-amazing-caves/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> There are approximately 17 species of plant that are endemic only to the island of Guam, and many more that are [[List of endemic plants in the Mariana Islands|endemic to the Mariana Islands]].  Numerous endemic insects have been described.<ref>{{Cite book |url=http://hbs.bishopmuseum.org/pubs-online/pdf/bull172.pdf |title=Insects of Guam-I, Bulletin 172 |date=1942 |publisher=Bernice P. Bishop Museum}}</ref><ref>{{Cite book |url=http://hbs.bishopmuseum.org/pubs-online/pdf/bull189.pdf |title=Insects of Guam-II, Bulletin 189 |date=1946 |publisher=Bernice P. Bishop Museum}}</ref><ref>{{Cite web |title=Insects of Micronesia |url=http://hbs.bishopmuseum.org/pubs-online/iom.html |access-date=2025-01-02 |website=hbs.bishopmuseum.org}}</ref>  There are approximately 29 [[List of land snails of the Mariana Islands|land snails]] listed as endemic to the island of Guam, although many are now endangered or presumed extinct.<ref>{{Cite web |last=Murphy |first=Shannon |date=2013-04-23 |title=Land Snails (Akaleha') of the Mariana Islands - Guampedia |url=https://www.guampedia.com/land-snails-akaleha-of-the-mariana-islands/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref><ref>{{Cite book |last1=Kerr |first1=Alexander M. |url=https://www.uog.edu/_resources/files/ml/technical_reports/148Kerr_and_Bauman_2013_UOGMLTechReport148.pdf |title=Annotated Checklist of the Land snails of the Mariana Islands, Micronesia |last2=Bauman |first2=Scott |date=2013 |publisher=University of Guam (UOG)}}</ref>  Guam once hosted 14 kinds of terrestrial [[List of birds of Guam|birds]], 7 of which were endemic to Guam on the species or subspecies level, although all but one of the 14 are now [[List of threatened, endangered and extinct species in the Mariana Islands|extinct, extirpated, or endangered]].<ref>{{Cite web |last=Murphy |first=Shannon |date=2009-09-30 |title=Native Forest Birds of Guam - Guampedia |url=https://www.guampedia.com/a-native-forest-birds-of-guam/ |access-date=2025-01-02 |website=www.guampedia.com |language=en-US}}</ref> Three locations on Guam ([[Guam National Wildlife Refuge]], [[Cocos Island (Guam)|Cocos Island]], and Mahlac Caves) have been identified as [[Important Bird Area|Important Bird Areas]] (IBA) by [[BirdLife International]] because they support populations of [[Micronesian starling|Micronesian starlings]], [[Mariana swiftlet|Mariana swiftlets]], [[Mariana crow|Mariana crows]], and Guam rails. The [[Guam rail]] became the second bird species to ever be downlisted from [[Extinct in the wild]] after a population was established on Cocos Island.<ref>{{Cite web |date=2019-12-10 |title=Species recoveries bring hope amidst the biodiversity crisis - IUCN Red List {{!}} IUCN |url=https://iucn.org/news/species/201912/species-recoveries-bring-hope-amidst-biodiversity-crisis-iucn-red-list |access-date=2025-01-07 |website=iucn.org |language=en}}</ref> Guam was home to three native bat species: the [[Guam flying fox|little Mariana fruit bat]] (''Pteropus tokudae''), now extinct; the endangered [[Pacific sheath-tailed bat]] (''Emballonura semicaudata rotensis''); and the endangered [[Mariana fruit bat]] (''Pteropus mariannus mariannus'').

[[File:20140402-APHIS-UNK-0004 (13592983734).jpg|thumb|The introduction of the [[brown tree snake]] nearly eradicated the native bird population.]]
Guam has experienced severe effects of [[invasive species]] upon the natural [[biodiversity]] of the island. These include the [[local extinction]] of endemic bird species after the introduction of the [[brown tree snake]], an infestation of the [[Oryctes rhinoceros|coconut rhinoceros beetle]] destroying [[coconut]] palms, and the effect of introduced [[feral]] [[mammal]]s and [[amphibian]]s.

[[Wildfire]]s plague the forested areas of Guam every [[dry season]] despite the island's humid climate. Most fires are caused by humans with 80% resulting from [[arson]].<ref>{{cite web|url=http://www.guamforestry.org/docs/final_guam_2004.pdf|title=Territory of Guam Fire Assessment January 2004|access-date=March 24, 2009|url-status=dead|archive-url=https://web.archive.org/web/20090324224423/http://www.guamforestry.org/docs/final_guam_2004.pdf|archive-date=March 24, 2009}}, pp. 6–7, guamforestry.org</ref> Poachers often start fires to attract deer to the new growth. Invasive grass species that rely on fire as part of their natural life cycle grow in many regularly burned areas. Grasslands and "barrens" have replaced previously forested areas leading to greater soil erosion.<ref name="National Park Service">{{cite web|url=http://www.nps.gov/archive/wapa/indepth/Park/Natural/fire/fireguam.htm|archive-url=https://web.archive.org/web/20071213232039/http://www.nps.gov/archive/wapa/indepth/Park/Natural/fire/fireguam.htm|archive-date=December 13, 2007|work=[[United States Department of the Interior]]|author=National Park Service|title=Fire and Guam|access-date=June 16, 2007|author-link=National Park Service}}</ref>

During the rainy season, sediment is carried by the heavy rains into the [[Fena Lake]] Reservoir and [[Ugum River]], leading to water quality problems for southern Guam. Eroded silt also destroys the marine life in reefs around the island. Soil stabilization efforts by volunteers and forestry workers (planting trees) have had little success in preserving natural habitats.<ref name="National Park Service" />[[File:Fish and coral in Tumon Bay Marine Preserve, Guam.jpg|thumb|Previously extensively [[dredging|dredged]], [[Tumon Bay]] is now a marine preserve.]]
Efforts have been made to protect Guam's coral reef habitats from pollution, eroded silt and overfishing, problems that have led to decreased fish populations. This has both ecological and economic value, as Guam is a significant [[Underwater diving on Guam|vacation spot for scuba divers]], and one study found that Guam's reefs are worth [[US$]]127 million per year.<ref>{{cite news |last1=Brown |first1=Val |title=Guam's Reefs are Important to Guam's Culture and Economy |url=https://www.newspapers.com/image/646794275 |access-date=October 1, 2021 |work=Pacific Daily News |date=May 30, 2008 |location=Agana Heights, Guam |page=5 |quote=The results indicated that Guam's reefs are worth $127 million per year |archive-date=October 1, 2021 |archive-url=https://web.archive.org/web/20211001213252/http://www.newspapers.com/image/646794275/ |url-status=live }}</ref> In recent years, the Department of Agriculture, Division of Aquatic and Wildlife Resources has established several new marine preserves where fish populations are monitored by biologists.<ref>{{cite news |url=http://www.guampdn.com/guampublishing/special-sections/mlsea/8-future.htm |archive-url=https://archive.today/20130103031256/http://www.guampdn.com/guampublishing/special-sections/mlsea/8-future.htm |url-status=dead |archive-date=January 3, 2013 |work=Pacific Daily News |title=Guam's Marine Preserves |last=Brown |first=Valerie |date=2006}}</ref> These are located at [[Pati Point]], [[Piti Bomb Holes]], [[Sasa Bay]], Achang Reef Flat, and [[Tumon Bay]].<ref>{{cite web |title=Sea Life |url=https://www.visitguam.com/chamorro-culture/nature/sea-life/ |website=Guam Visitors Bureau |access-date=May 20, 2020 |archive-date=May 31, 2020 |archive-url=https://web.archive.org/web/20200531225300/https://www.visitguam.com/chamorro-culture/nature/sea-life/ |url-status=live }}</ref>

Before adopting [[United States Environmental Protection Agency|U.S. Environmental Protection Agency]] standards, portions of Tumon Bay were dredged by the hotel chains to provide a better experience for hotel guests.<ref>{{cite web|url=http://www.guamepa.govguam.net/programs/epr/sediment_report.pdf|work=EPA Guam Report|title=Management of Contaminated Harbor Sediments in Guam|url-status=live|archive-url=https://web.archive.org/web/20070808031615/http://www.guamepa.govguam.net/programs/epr/sediment_report.pdf|archive-date=August 8, 2007}}</ref><ref>{{cite web|url=http://www.pcrguam.com/press_releases/Tumon_Bay.htm|work=Directions Magazine; June/July 1996|title=Tumon Bay – Engineering a Better Environment|author=Packbier, Paul E.R.|access-date=October 19, 2011|url-status=dead|archive-url=https://web.archive.org/web/20110726141402/http://www.pcrguam.com/press_releases/Tumon_Bay.htm|archive-date=July 26, 2011}}</ref> Tumon Bay has since been made into a preserve. A federal [[Guam National Wildlife Refuge]] in northern Guam protects the decimated [[sea turtle]] population in addition to a small colony of [[Mariana fruit bats]].<ref>{{cite journal|last=Holmes III|first=Rolston|title=Environmental Ethics in Micronesia, Past and Present, Part II—Guam Today: Still "on the Edge." Colonial Legacy and American Presence|journal=International Society for Environmental Ethics Newsletter|volume=12|issue=3|year=2001|url=http://www.cep.unt.edu/ISEE/n12-3-01.htm|access-date=June 16, 2007|archive-url=https://web.archive.org/web/20070609092403/http://www.cep.unt.edu/ISEE/n12-3-01.htm|archive-date=June 9, 2007|url-status=live}}</ref>

Harvest of sea turtle eggs was a common occurrence on Guam before World War II. The [[green sea turtle]] (''Chelonia mydas'') was harvested legally on Guam before August 1978, when it was listed as threatened under the Endangered Species Act. The [[hawksbill sea turtle]] (''Eretmochelys imbricata'') has been on the endangered list since 1970. In an effort to ensure the protection of sea turtles on Guam, routine sightings are counted during aerial surveys and nest sites are recorded and monitored for hatchlings.