Tag Archives: lizards

Detection Dogs and DNA on the Trail of Endangered Lizards

Detection dogs trained to sniff out the scat of an endangered lizard in California’s San Joaquin Valley, combined with genetic species identification, could represent a new, noninvasive sampling technique for lizard conservation worldwide. That is according to a study published by the University of California, Davis, in partnership with the nonprofit Working Dogs for Conservation, U.S. Geological Survey and the U.S. Bureau of Land Management.

Scientists have used trained conservation dogs to locate scat and collect DNA samples for everything from bears and foxes to gorillas and whales. But the technique had not been used for reptiles until this study, for which scientists developed a novel approach to identify the presence of the blunt-nosed leopard lizard in the Panoche Hills Recreation Area and Carrizo Plain National Monument, both managed by BLM.

They developed new methods to recover DNA from feces and genetically identify lizard species in the same area. The study, published in the Journal of Wildlife Management, is a proof of concept for a host of reptiles.

Lizard detection dog

Seamus, a trained detection dog, alerts his handler to the presence of scat. (Mike Westphal, Bureau of Land Management)

“So many reptilian species have been hit so hard,” said lead author Mark Statham, an associate researcher with the Mammalian Ecology and Conservation Unit of the UC Davis School of Veterinary Medicine. “A large proportion of them are endangered or threatened. This is a really valuable way for people to be able to survey them.”

No direct contact needed

Current methods for surveying lizard species typically rely on live capture or visual surveys. Scat sampling allows biologists to study elusive, rare or dangerous animals without the need for direct contact. In addition to informing about the presence, habitat and genetics of an animal, scat can also be analyzed to inform researchers about diet, hormones, parasites and other health factors.

Using the new method, the authors genetically identified specific species for 78 percent of the 327 samples collected by dog-handler teams across four years. Most (82 percent) of those identified were confirmed as being from blunt-nosed leopard lizards.

To meet regulatory monitoring requirements, more research is needed to assess the viability of using detection dogs to recover usable DNA at larger scales. But the research highlights the broad potential this method holds for surveying and monitoring reptiles.

Funding was provided by the Bureau of Land Management.

Source:  UC Davis media release

Scat sniffer dogs help tell the story of endangered lizards

Dogs can be trained to find almost anything (people, drugs, weapons, poached ivory) but one York University researcher had them detect something a little unusual – the scat of endangered blunt-nosed leopard lizards.

The scat detection dogs helped biology PhD student Alex Filazzola discover not only scat, but the importance of shrubs in preserving lizard populations in the face of climate change.

“The loss of these lizards would likely have a cascade effect on other species,” said Filazzola, the study lead.

The research team geo-tagged 700 Ephedra californica shrubs in a 32.3-hectare area of the Panoche Hills Management Area in San Joaquin Valley, California. They then took two scat detection dogs from Working Dogs for Conservation on the hunt for lizard scat in 2013 and 2014.

In 2014, there was a drought during which time lizard scat was found more frequently under shrubs, especially those with dense canopy cover, than out in the open. The shrubs proved instrumental in providing critical micro-environments for the blunt-nosed leopard lizards, in particular, shady places to regulate their body temperature in extreme heat, as well as refuge from predators. The lizards use rodent burrows, most often found under shrubs, to escape predators.

“As the climate warms and lizards find it more difficult to regulate their body temperatures in the heat, these findings could help preserve them not only in California, but globally,” said Filazzola of York U’s Faculty of Science. “It demonstrates how much animals rely on plants for survival that goes beyond that of simply eating them. Positive plant-animal interactions could further support animal populations that are already threatened.”

The research, “Non-trophic interactions in deserts: Facilitation, interference, and an endangered lizard species,” was published in the journal Basic and Applied Ecology.

Once abundant in the San Joaquin Valley, agriculture and industrialization has reduced the lizards’ range by close to 85 per cent. Predictions of increased drought in the area put the lizards at a high risk of being wiped out. The study also pointed out that management techniques used over the past 50 years have done little to change the endangered status of the lizards.

“Planting shrubs, such as the Ephedra californica, could prove critical in managing and preserving endangered species in high-stress or arid ecosystems, such as a desert,” said Filazzola. “Continuing to remove these shrubs to install solar panels, however, further endangers this species.”

In addition, the study found that invasive grasses in the desert were not beneficial. They interfered with the lizards’ ability to move around and limited available habitat by reducing the variety of rodent species which create burrows. The invasive grasses also competed for space with shrubs and caused diminished shrub growth. Managing invasive plant species is therefore crucial in these ecosystems.

The research was funded by the Central Coast Field Office of the Bureau of Land Management, Department of the Interior, a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada and York University.

Source: York University media release