PROBLEM STATEMENT/JUSTIFICATION:

Need-- The recent "explosive growth" of the international pet trade, with the United States in the lead, has led to widespread concern regarding the sustainability of wild stocks of reptiles. A recent report by the World Wildlife Fund reports that the United States exported 9.5 million reptiles in 1996 primarily for the pet trade. The majority of this trade is in a few species such as the green iguana and the red-eared slider, but captive-bred boid and colubrid snakes are a very important high end element of this trade. Of particular concern is the recent explosion in varieties of rosy boas (Lichanura trivirgata) now proportedly being bred in captivity.

This snake occurs naturally in California, Arizona, and Mexico. Daily bag limits of 2 exist for rosy boas in both states with a possession limit of 2 in California and 4 in Arizona. It is generally not possible to obtain a permit from Mexico for legal commercial export of reptiles. Recently California has changed its laws regarding the commercial captive propagation of rosy boas and with a permit there is no limit on possession. Without physical, or genetic markers on the snakes that indicate they are captive born, it is only possible to track the trade through bill of sales and other records required of the permitees. Thus there is no way to prevent or prove the augmentation of this trade with wild poached animals. The concern in particular is that these snakes are still being collected in large numbers from the wild and the wild animals are moving into the pet trade.

Additionally, there is evidence that impacts from roads, habitat fragmentation, and urbanization are greatly impacting rosy boa populations, even within natural reserves. These impacts will continue to grow as the human population of California, Arizona and northwestern Mexico continues to increase. Proactive steps need to be taken to insulate the natural lands from these impacts through reserve design modifications based on the biology of the snakes.

Background-- The rosy boa (Lichanura trivirgata) is one of two boid species native to the United States, the other being the rubber boa (Charina bottae). Recent work on the phylogeny of these species has concluded that they are primitive members of the Erycine boid family most closely related to the African burrowing python (Calabaria). The recent taxonomic change recommended in this work is to include both genera Lichanura and Calabaria in the genus Charina, although most of the literature has not adopted this yet. Lichanura is generally considered to contain one species currently, with up to five subspecies, although other (additional) names may be used by the captive breeders. Historically, there has been a debate as to whether the southern forms in Mexico represented a second species. Generally the agreement is that only one species is represented, although this has yet to be tested with molecular data. The differentiation between any subspecies is not known, and this species may show high levels of population substructure even within subspecies as it occurs disjunctly across many mountain ranges across its distribution.

Rosy boas are one of the defining reptiles of the southwest, along with Gila monsters, desert tortoises, and chuckwallas. Rosy boas occupy a variety of habitat types that change geographically. Generally rocks are a constant feature of the habitat. Until recently nothing was known of their movement patterns or home range size, and generally very little is known about the natural history of this species.

The increase in their popularity in the pet trade and the lack of knowledge about their population biology, has raised flags regarding the impacts of this industry on the future of natural rosy boa stocks. Additionally, recent research by Fisher and Case on the reptiles of coastal southern California is indicating that several additional factors may be leading to widespread declines in rosy boas. These factors include roads, habitat loss, increased fire frequency, urban light pollution, and poaching. A multi-pronged approach to address various aspects of the biology of the rosy boas is necessary to understand the population status and conservation needs of this species. The research proposed here will build on existing data, primarily historic, to evaluate hypotheses about decline, to examine life-history attributes especially relative to reserve design, it will also determine realistic estimates of captive production, model current distribution, and clarify the phylogeography of the species, especially with regards to subspecies designations.

OBJECTIVES:

1. To determine whether the species has declined relative to other snake species based on historic data.

2. To gain an understanding of the habitat requirements, life history attributes, and movement patterns of this species.

3. To determine population substructure of Lichanura trivirgata, utilizing molecular techniques including DNA sequencing.

4. To quantify legal/illegal take of the species from the wild, and estimate captive production.

5. To identify current and potential threats to this species conservation and develop recommendations for the management of this species and its habitats.

Study Areas:

Southern California (Coastal and Desert), and possibly southwestern Arizona. Night driving research will be conducted in the Mojave in Joshua Tree National Monument (JTNM), and in Anza Borrego State Park. Radiotracking research sites will include at least one coastal and one desert location. Possible locations for this work with documented rosy boa populations will be JTNM, Twentynine Palms, Windmill Park (above Whitewater Canyon), Santa Margarita Ecological Reserve, Wild Animal Park, Mission Trails Regional Park, Camp Pendleton MCB, or San Diego National Wildlife Refuge Complex.

Related Web Page
Intraspecific Phylogeography of the Rosy Boa