Editing Axolotl (section)

=== Threats ===
Axolotls are only native to the Mexican Central Valley. Although the native axolotl population once extended through most of the lakes and wetlands that make up this region, the native habitat is now limited to Lake Xochimilco as a result of the expansion of Mexico City. Lake Xochimilco is not a large body of water, but rather a small series of artificial channels, small lakes, and temporary wetlands.

Lake Xochimilco has poor water quality, caused by the region's aquaculture and agriculture demands. It is also maintained by inputs of only partially treated wastewater. Water quality tests reveal a low nitrogen-phosphorus ratio and a high concentration of chlorophyll a, which are indicative of an oxygen-poor environment that is not well-suited for axolotls.<ref>{{Cite journal |last1=Nandini |first1=Sarma |last2=García |first2=Pedro Ramirez |last3=Sarma |first3=S. S. S. |date=2016 |title=Water quality in Lake Xochimilco, Mexico: zooplankton indicators and Vibrio cholerae |url=https://www.jlimnol.it/index.php/jlimnol/article/view/jlimnol.2015.1213 |journal=Journal of Limnology |language=en |volume=75 |issue=1 |doi=10.4081/jlimnol.2015.1213 |issn=1723-8633|doi-access=free }}</ref> In addition, the intensive use of pesticides from agriculture around Lake Xochimilco causes run off into the lake and a reduction of habitat quality for axolotls. The pesticides used contain chemical compounds that studies show to sharply increase mortality in axolotl embryos and larvae. Of the surviving embryo and larvae, there is also an increase of morphological, behavior, and activity abnormalities.<ref>{{Cite journal |last1=Robles-Mendoza |first1=C. |last2=García-Basilio |first2=C. |last3=Cram-Heydrich |first3=S. |last4=Hernández-Quiroz |first4=M. |last5=Vanegas-Pérez |first5=C. |date=2009-02-01 |title=Organophosphorus pesticides effect on early stages of the axolotl Ambystoma mexicanum (Amphibia: Caudata) |url=https://www.sciencedirect.com/science/article/pii/S004565350801223X |journal=Chemosphere |language=en |volume=74 |issue=5 |pages=703–710 |doi=10.1016/j.chemosphere.2008.09.087 |pmid=19012946 |bibcode=2009Chmsp..74..703R |issn=0045-6535}}</ref>

Another factor that threatens the native axolotl population is the introduction of invasive species such as the Nile tilapia and common carp. These invasive fish species threaten axolotl populations by eating their eggs or young and by out-competing them for natural resources. The presence of these species has also been shown to change the behavior of axolotls, causing them to be less active to avoid predation. This reduction in activity greatly impacts the axolotls foraging and mating opportunities.<ref>{{Cite journal |last1=Alcaraz |first1=Guillermina |last2=López-Portela |first2=Xarini |last3=Robles-Mendoza |first3=Cecilia |date=2015-07-01 |title=Response of a native endangered axolotl, Ambystoma mexicanum (Amphibia), to exotic fish predator |url=https://doi.org/10.1007/s10750-015-2194-4 |journal=Hydrobiologia |language=en |volume=753 |issue=1 |pages=73–80 |doi=10.1007/s10750-015-2194-4 |bibcode=2015HyBio.753...73A |s2cid=254550469 |issn=1573-5117}}</ref>

With such a small native population, there is a large loss of genetic diversity. This lack of genetic diversity can be dangerous for the remaining population, causing an increase in inbreeding and a decrease in general fitness and adaptive potential. It ultimately raises the axolotl's risk for extinction, something that they are already in danger of. Studies have found indicators of a low interpopulation gene flow and higher rates of genetic drift. These are likely the result of multiple "bottleneck" incidents in which events that kill off several individuals of a population occur and sharply reduce the genetic diversity of the remaining population. The offspring produced after bottleneck events have a greater risk of showing decreased fitness and are often less capable of adaptation down the line. Multiple bottleneck events can have disastrous effects on a population. Studies have also found high rates of relatedness that are indicative of inbreeding. Inbreeding can be especially harmful as it can cause an increase in the presence of deleterious, or harmful, genes within a population.<ref>{{Cite journal |last1=Parra-Plea |first1=G |last2=Zamudio |first2=K.R. |last3=Recuero |first3=E. |last4=Aguilar-=Miguel |first4=X. |last5=Huaxuz |first5=D. |last6=Zambrano |first6=L. |date=2011 |title=Conservation genetics of threatened Mexican axolotls (Ambystoma) |url=https://doi.org/10.1111/j.1469-1795.2011.00488.x |journal= Animal Conservation|volume=15 |issue=1 |pages=61–72|doi=10.1111/j.1469-1795.2011.00488.x |s2cid=46992721 }}</ref> The detection of introgressed tiger salamander (''A. tigrinum'') DNA in the laboratory axolotl population raises further concerns about the suitability of the captive population as an ark for potential reintroduction purposes.<ref>{{Cite journal |last1=Woodcock |first1=M. Ryan |last2=Vaughn-Wolfe |first2=Jennifer |last3=Elias |first3=Alexandra |last4=Kump |first4=D. Kevin |last5=Kendall |first5=Katharina Denise |last6=Timoshevskaya |first6=Nataliya |last7=Timoshevskiy |first7=Vladimir |last8=Perry |first8=Dustin W. |last9=Smith |first9=Jeramiah J. |last10=Spiewak |first10=Jessica E. |last11=Parichy |first11=David M. |last12=Voss |first12=S. Randal |date=2017-01-31 |title=Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Ambystoma mexicanum |journal=Scientific Reports |language=en |volume=7 |issue=1 |pages=6 |doi=10.1038/s41598-017-00059-1 |pmid=28127056 |issn=2045-2322|pmc=5428337 |bibcode=2017NatSR...7....6W }}</ref>

There has been little improvement in the conditions of the lake or the population of native axolotls over the years.<ref>{{cite news|url= http://news.bbc.co.uk/earth/hi/earth_news/newsid_8220000/8220636.stm |publisher= BBC |title= Axolotl verges on wild extinction |author= Matt Walker |date=2009-08-26 |access-date=2010-06-28}}</ref><ref>{{Cite web|last=PetAquariums.com|title=Are Axolotls Endangered? You Need To Be Careful…|url=https://www.petaquariums.com/2020/10/21/are-axolotls-endangered-you-need-to-be-careful/|access-date=2021-06-26|website=PetAquariums.com|date=22 April 2020 |language=en-US}}</ref> Many scientists are focusing their conservation efforts on translocation of captive-bred individuals into new habitats or reintroduction into Lake Xochimilco. The Laboratorio de Restauracion Ecologica (LRE) in the Universidad Nacional Autonoma de Mexico (UNAM) has built up a population of more than 100 captive-bred individuals. These axolotls are mostly used for research by the lab but plans of a semi-artificial wetland inside the university have been established and the goal is to establish a viable population of axolotls within it. Studies have shown that captive-bred axolotls that are raised in a semi-natural environment can catch prey, survive in the wild, and have moderate success in escaping predators. These captive-bred individuals can be introduced into unpolluted bodies of water or back into Lake Xochimilco to establish or re-establish a wild population.<ref>{{Cite journal |last1=Ramos |first1=A.G. |last2=Mena-Gonzalez |first2=H. |last3=Zambrano |first3=L |date=2021 |title=The potential of temporary shelters to increase survival of the endangered Mexican axolotl |url=https://doi.org/10.1002/aqc.3520 |journal=Aquatic Conservation: Marine and Freshwater Ecosystems |volume=31 |issue=6 |pages=1535–1542|doi=10.1002/aqc.3520 |bibcode=2021ACMFE..31.1535R |s2cid=235587173 }}</ref><ref>{{Cite news |last=Paúl |first=María Luisa |date=2023-12-01 |title=Mexico wants you to adopt an axolotl, the amphibian that never grows up |language=en-US |newspaper=Washington Post |url=https://www.washingtonpost.com/nation/2023/12/01/axolotl-mexican-salamander-adoption-campaign/ |access-date=2023-12-01 |issn=0190-8286}}</ref>

A 2025 study confirmed the viability of releasing captive-bred axolotls into the wild, with recaptured animals putting on weight compared to their release weight, though this practice risks the loss of the axolotls through predation, as a number of released axolotls were preyed upon by [[great egret]]s.<ref>{{cite journal |author1=Ramos |first=Alejandra G. |author2=Horacio Mena |author3=David Schneider |author4=Luis Zambrano |date=30 April 2025 |title=Movement ecology of captive-bred axolotls in restored and artificial wetlands: Conservation insights for amphibian reintroductions and translocations |journal=PLOS ONE |volume=20 |issue=4 |pages=e0314257 |doi=10.1371/journal.pone.0314257 |doi-access=free |pmid=40305450 |pmc=12043180 }}</ref><ref>{{cite web |title=Good news for the adorable axolotl — ones born in captivity could survive in the wild |url=https://www.npr.org/2025/05/06/nx-s1-5383896/good-news-for-the-adorable-axolotl-ones-born-in-captivity-could-survive-in-the-wild |website=npr.org |date=6 May 2025 |publisher=NPR |access-date=12 May 2025 |last1=Fink |first1=Kathryn }}</ref><ref>{{cite web |last1=Gill |first1=Victoria |title=Endangered axolotl release raises hopes for rare amphibian |url=https://www.bbc.com/news/articles/cm2xr2jzelyo |website=bbc.com |date=30 April 2025 |publisher=British Broadcasting Corporation |access-date=12 May 2025}}</ref>