Small, rare crayfish thought extinct is rediscovered in cave in Huntsville city limits

Dr. Matthew L. Niemiller’s team found individuals of the Shelta Cave Crayfish in 2019 and 2020 excursions into Shelta Cave – its only home.

HUNTSVILLE, Ala. (June 1, 2022) – A small, rare crayfish thought to be extinct for 30 years has been rediscovered in a cave in the City of Huntsville in northern Alabama by a team led by an assistant professor at The University of Alabama in Huntsville (UAH).

Dr. Matthew L. Niemiller’s team found individuals of the Shelta Cave Crayfish, known scientifically as Orconectes sheltae, in 2019 and 2020 excursions into Shelta Cave – its only home.

The Shelta Cave Crayfish is known to exist only in Shelta Cave. Courtesy Dr. Matthew L. Niemiller

Dr. Niemiller, an assistant professor of biological sciences at UAH, a part of the University of Alabama System, is co-author of a paper on the findings in the journal Subterranean Biology. Besides Dr. Niemiller, authors are UAH’s Katherine E. Dooley and K. Denise Kendall Niemiller, and Nathaniel Sturm of the University of Alabama.

The crayfish’s home is a 2,500-foot cave system that’s owned and managed by the National Speleological Society (NSS) and is unobtrusively located beneath the organization’s national headquarters in northwest Huntsville and is surrounded by subdivisions and bustling roadways.

Map of Shelta Cave showing the distribution of aquatic habitat during high water levels and the location of Shelta Cave Crayfish observations (black crayfish symbol) during the study. Map modified with permission of the Alabama Cave Survey.

“The crayfish is only a couple of inches long with diminutive pincers that are called chelae,” Dr. Niemiller says. “Interestingly, the crayfish has been known to cave biologists since the early 1960s but was not formally described until 1997 by the late Dr. John Cooper and his wife Martha.”

But the aquatic ecosystem, including the Shelta Cave Crayfish, crashed sometime in the early 1970s. The crash may be related to a gate that was built to keep people out of the cave and yet still allow a grey bat maternity population to still move freely in and out.

Even before the decline in the aquatic cave community, the Shelta Cave Crayfish was never common compared to the other two species, Southern Cave Crayfish (Orconectes australis) and Alabama Cave Crayfish (Cambarus jonesi).

“To the best of our knowledge, only 115 individuals had been confirmed from 1963 through 1975. Since then, only three have been confirmed – one in 1988 and the two individuals we report in 2019 and 2020,” Dr. Niemiller says.

“After a couple of decades of no confirmed sightings and the documented dramatic decline of other aquatic cave life at Shelta Cave, it was feared by some, including myself, that the crayfish might now be extinct.”

While it’s encouraging that the Shelta Cave Crayfish still persists, he says scientists still haven’t rediscovered other aquatic species that once lived in the cave system, such as the Alabama Cave Shrimp and Tennessee Cave Salamander. 

“The groundwater level in Shelta Cave is the result of water that works its way naturally through the rock layers above the cave – called epikarst – from the surface,” says Dr. Niemiller. “However, urbanization in the area above the cave system may have altered rates at which water infiltrates into the cave and also increased rates of pollutants, such as pesticides and heavy metals entering the cave system.”

The crayfish was rediscovered during an aquatic survey aimed toward documenting all life that encountered in the cave system.

“I really wasn’t expecting to find the Shelta Cave Crayfish. My students, colleagues and I had visited the cave on several occasions already leading up to the May 2019 trip,” Dr. Niemiller says. “We would be fortunate to see just a couple of Southern Cavefish and Southern Cave Crayfish during a survey.”

Dr. Matthew L. Niemiller snorkels in Shelta Cave, where a species of crayfish believed to be extinct was rediscovered. Photo by Amata Hinkle

While snorkeling in about 15 feet of water in North Lake located in the Jones Hall section of the cave, Dr. Niemiller spotted a smaller-sized cave crayfish below him.

“As I dove and got closer, I noticed that the chelae, or pincers, were quite thin and elongated compared to other crayfish we had seen in the cave,” he says. “I was fortunate to swoop up the crayfish with my net and returned to the bank.”

“The second Shelta Cave Crayfish that we encountered was in August 2020 in the West Lake area,” he says.

The team had searched much of the area and didn’t see much aquatic life. As they started to make their way out the lake passage to return to the surface, Nate Sturm, a master’s student in biology at the University of Alabama who had accompanied the lab for the trip, noticed a small white crayfish in an area that the team had previously walked through.

To aid identification, the team analyzed short fragments of mitochondrial DNA in the tissue samples collected.

“We compared the newly generated DNA sequences with sequences already available for other crayfish species in the region,” Dr Niemiller says. “A challenge we faced was that no DNA sequences existed prior to our study for the Shelta Cave Crayfish, so it was a bit of a process of elimination, so to speak.”

Outside of the dissertation work done by Dr. Cooper, little about the life history and ecology of the species is known.

 “Groundwater is critically important not just for the organisms that live in groundwater ecosystems, but for human society for drinking water, agriculture, etc.,” Dr. Niemiller says.

“The organisms that live in groundwater provide important benefits, such as water purification and biodegradation,” he says. “They also can act like ‘canaries in the coal mine,’ indicators of overall groundwater and ecosystem health.” 

Research article:

Dooley KE, Niemiller KDK, Sturm N, Niemiller ML (2022) Rediscovery and phylogenetic analysis of the Shelta Cave Crayfish (Orconectes sheltae Cooper & Cooper, 1997), a decapod (Decapoda, Cambaridae) endemic to Shelta Cave in northern Alabama, USA. Subterranean Biology 43: 11-31. https://doi.org/10.3897/subtbiol.43.79993

About The University of Alabama in Huntsville

Launched from America’s quest to conquer space, The University of Alabama in Huntsville is one of America’s premier doctoral-granting, research-intensive universities. Located in the second largest research park in the United States, UAH has robust capabilities in astrophysics, cybersecurity, data analytics, logistics and supply chain management, optical systems and engineering, reliability and failure analysis, rotorcraft and unmanned systems, severe weather, space propulsion and more. UAH prepares students for demanding positions in engineering, the sciences, business, nursing, education, the arts, humanities and social sciences.

Read the full press release by The University of Alabama in Huntsville.

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What can we learn from vanishing wildlife species: the case of the Pyrenean Ibex

The sad history of the Pyrenean Ibex (Capra pyrenaica pyrenaica) is a powerful example of species loss due to causes related to human activity. DNA analyses of Pyrenean Ibex found evidence that, after a demographic expansion about 20,000 years ago, its population went through a bottleneck caused by hunting, inbreeding and other factors, which ultimately caused its extinction. Their research is published in the open-access, peer-reviewed journal Zoosystematics and Evolution.

Only the French mountaineer and photographer Bernhard Clos managed to take a series of good photos of the Bucardo, as the Pyrenean Ibex is called on the Spanish side. Photo: Bernhard Clos

Likely the first extinction event of the 2000s in Europe, the sad history of the Pyrenean Ibex (Capra pyrenaica pyrenaica) is a powerful example of the ever-increasing species loss worldwide due to causes related to human activity. It can, however, give us valuable information on what should be done (or avoided) to halt this extinction vortex.

The distribution of this subspecies of Iberian Ibex was limited to the French and Spanish Pyrenees. Its first mention in an official written document, dating back to 1767, already refers to it as extremely rare. Like many other mountain goats, it was almost hunted to extinction before its killing became prohibited in 1913. Neither the institution of a national park (Ordesa & Monte Perdido), nor a conservation project with European LIFE program funding could stop the extinction of the Pyrenean Ibex eventually officialised on January 6, 2000. But the story of this charismatic animal did not end there – a controversial cloning program was started instantly with no scientific agreement, nor support from regional environmental NGOs, claiming that de-extinction was possible even in the absence of further DNA studies.

Laña, the last surviving Pyrenean Ibex, returned as a mounted animal to Torla-Ordesa on the 6th November 2012 after its controversial cloning attempt. Her skin is now exhibited in the visitors centre of Ordesa & Monte Perdido National Park. Photo: Manolo Grasa

To find out more about the drivers of its extinction, an international team composed of 7 nationalities built a database of all known museum specimens and reconstructed the demographic history of the Pyrenean Ibex based on DNA evidence. Their research is published in the open-access, peer-reviewed journal Zoosystematics and Evolution.

The research found that after a population expansion between 14,000 and 29,000 years ago (which is quite recent from a genetic point of view), a significant loss of genetic diversity followed between approximately 15,000 and 7,500 years BP, and continued until present. By that time, the Pyrenean Ibex also lived outside the Pyrenean mountain chain, but, gradually, its distribution was reduced to only one valley in the Ordesa National Park in the Spanish Pyrenees.

The adventures of the British hunter E.N. Buxton were published in 1893. This engraving represents a hunting party in the Ordesa Valley (Spanish Pyrenees).

Written sources confirm hunting of the Pyrenean Ibex from as early as the 14th century, and during the 19th and 20th century it became a common target for trophy hunters. Undoubtedly, hunting played an important role in reducing its population numbers and distribution area, but it is not possible – with the information currently available – to pinpoint it as the straw that broke the camel’s back. Infectious diseases that originate from livestock (for instance, those caused by the bluetongue virus, BTV, and sarcopses) are capable of decimating other subspecies of Iberian Ibex in extremely short periods of time.

While the relative contribution of various factors remains largely unknown, it seems that hunting and diseases transmitted from other animals have been effective in drastically reducing the number of Pyrenean ibexes over the last two centuries, because they were acting on an already genetically weakened population. This low genetic diversity, combined with inbreeding depression and reduced fertility, brought the population beyond the minimum viable size – from that point onwards, extinction was inevitable.

This case study shows the importance of historical biological collections for genetic analyses of extinct species. A privately owned 140-year-old trophy preserved in Pau, France, was genotyped as part of this research, showing that private individuals may possess material of high value. As there is little knowledge of such resources, the authors call for the creation of an online public database of private collections hosting biological material for the benefit of biodiversity studies. 

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Original source:
Forcina G, Woutersen K, Sánchez-Ramírez S, Angelone S, Crampe JP, Pérez JM, Fandos P, Granados JE, Jowers MJ (2021) Demography reveals populational expansion of a recently extinct Iberian ungulate. Zoosystematics and Evolution 97(1): 211-221. https://doi.org/10.3897/zse.97.61854

Under Extinction Pressure: Rare Australian bee found after 100 years

A widespread field search for a rare Australian native bee (Pharohylaeus lactiferus) that had not been recorded for almost a century found the species has been there all along – but is probably under increasing pressure to survive. Prior to this study, only six individuals had been found, with the last published record of this Australian endemic bee species, from 1923 in Queensland.

Male Pharohylaeus lactiferus bee. Photo by James Dorey.

A widespread field search for a rare Australian native bee (Pharohylaeus lactiferus) that had not been recorded for almost a century found the species has been there all along – but is probably under increasing pressure to survive. Prior to this study, only six individuals had been found, with the last published record of this Australian endemic bee species, from 1923 in Queensland.

“This is concerning because it is the only Australian species in the Pharohylaeus genus and nothing was known of its biology,”

Flinders University researcher and biological sciences PhD candidate James Dorey says in the new scientific paper in the peer-reviewed, open-access Journal of Hymenoptera Research.

The ‘hunt’ began after bee experts Olivia Davies and Dr Tobias Smith raised the possibility of the species’ extinction based on the lack of any recent sightings. The ‘rediscovery’ followed an extensive sampling of 225 general and 20 targeted sampling sites across New South Wales and Queensland.

Along with extra bee and vegetation recordings from the Atlas of Living Australia, which lists 500 bee species in New South Wales and 657 in Queensland, the Flinders researchers sought to assess the latest levels of true diversity, warning that habitat loss and fragmentation of Australia’s rainforests, along with wildfires and climate change, are likely to put extinction pressure on this and other invertebrate species.  

“Three populations of P. lactiferous were found by sampling bees visiting their favoured plant species along much of the Australian east coast, suggesting population isolation,”

Mr Dorey reports.

Highly fragmented habitat and potential host specialisation might explain the rarity of P. lactiferus.

Additionally, the scientists remind of previous findings that Australia has already cleared more than 40% of its forests and woodlands since European colonisation, leaving much of the remainder fragmented and degraded.

“My geographical analyses used to explore habitat destruction in the Wet Tropics and Central Mackay Coast bioregions indicate susceptibility of Queensland rainforests and P. lactiferus populations to bushfires, particularly in the context of a fragmented landscape,”

Mr Dorey says.

The study also warns the species is even more vulnerable as they appear to favour specific floral specimens and were only found near tropical or sub-tropical rainforest – a single vegetation type.

“Collections indicate possible floral and habitat specialisation with specimens only visiting firewheel trees (Stenocarpus sinuatu), and Illawarra flame trees (Brachychiton acerifolius), to the exclusion of other available floral resources.”

Known populations of P. lactiferus remain rare and susceptible to habitat destruction (e.g. caused by changed land use or events such as fires), the paper concludes.

“Future research should aim to increase our understanding of the biology, ecology and population genetics of P. lactiferus.”

Female Pharohylaeus lactiferus bee. Photo by James Dorey.

“If we are to understand and protect these wonderful Australian species, we really need to increase biomonitoring and conservation efforts, along with funding for the museum curation and digitisation of their collections and other initiatives,”  

Mr Dorey says.

Research paper:

Dorey JB (2021) Missing for almost 100 years: the rare and potentially threatened bee, Pharohylaeus lactiferus (Hymenoptera, Colletidae). Journal of Hymenoptera Research 81: 165-180. https://doi.org/10.3897/jhr.81.59365

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‘Insectageddon’ is ‘alarmist by bad design’: Scientists point out the study’s major flaws

Many insects species require pristine environments, including old-growth forests. Photo by Atte Komonen.

Earlier this year, a research article triggered a media frenzy by predicting that as a result of an ongoing rapid decline, nearly half of the world’s insects will be no more pretty soon

Amidst worldwide publicity and talks about ‘Insectageddon’: the extinction of 40% of the world’s insects, as estimated in a recent scientific reviewa critical response was published in the open-access journal Rethinking Ecology.

Query- and geographically-biased summaries; mismatch between objectives and cited literature; and misuse of existing conservation data have all been identified in the alarming study, according to Drs Atte Komonen, Panu Halme and Janne Kotiaho of the University of Jyväskylä (Finland). Despite the claims of the review paper’s authors that their work serves as a wake-up call for the wider community, the Finnish team explain that it could rather compromise the credibility of conservation science.

The first problem about the paper, titled “Worldwide decline of the entomofauna: A review of its drivers” and published in the journal Biological Conservation, is that its authors have queried the Web of Science database specifically using the keywords “insect”, “decline” and “survey”.

“If you search for declines, you will find declines. We are not questioning the conclusion that insects are declining,” Komonen and his team point out, “but we do question the rate and extent of declines.”

Many butterflies have declined globally. Scolitantides orion, for example, is an endangered species in Finland. Photo by Atte Komonen.

The Finnish research team also note that there are mismatches between methods and literature, and misuse of IUCN Red List categories. The review is criticised for grouping together species, whose conservation status according to the International Union for Conservation of Nature (IUCN) is Data Deficient with those deemed Vulnerable. By definition, there are no data for Data Deficient species to assess their declines.

In addition, the review paper is seen to use “unusually forceful terms for a peer-reviewed scientific paper,” as the Finnish researchers quote a recent news story published in The Guardian. Having given the words dramatic, compelling, extensive, shocking, drastic, dreadful, devastating as examples, they add that that such strong intensifiers “should not be acceptable” in research articles.

“As actively popularising conservation scientists, we are concerned that such development is eroding the importance of the biodiversity crisis, making the work of conservationists harder, and undermining the credibility of conservation science,” the researchers explain the motivation behind their response.

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Original source:

Komonen A, Halme P, Kotiaho JS (2019) Alarmist by bad design: Strongly popularized unsubstantiated claims undermine credibility of conservation science. Rethinking Ecology 4: 17-19. https://doi.org/10.3897/rethinkingecology.4.34440