Dean A Williams

Texas Christian University | TCU · Department of Biology

Multiple mating is common in Sea Turtles, and previous studies have suggested that levels of multiple paternity are higher in larger rookeries compared with smaller rookeries. As a result, smaller rookeries may be more vulnerable to the loss of genetic variation than would larger rookeries. The critically endangered Kemp’s Ridley Sea Turtle (Lepido...

The Texas horned lizard ( Phrynosoma cornutum ) inhabits much of the southern Great Plains of North America. Since the 1950s, this species has been extirpated from much of its eastern range and has suffered declines and local extinctions elsewhere, primarily due to habitat loss. Plans are underway to use captive breeding to produce large numbers of...

Introduced species can diverge from their source population when they become established in a new ecosystem. The Texas Horned Lizard (Phrynosoma cornutum) is native to the western United States (US) and was historically introduced to several locations in the southeastern US. We studied three introduced populations in South Carolina, US to determine...

A new species of gecko, Lygodactylus tsavoensis sp. nov., is described from Tsavo Conservation Area in southeastern Kenya. It is a member of the Lygodactylus picturatus group and is distinguished from other closely related species by its small size (maximum 35 mm SVL), five postpostmental scales, seven precloacal pores, and a distinctive color patt...

Monoecious and dioecious biotypes of Hydrilla verticillata were introduced from Asia into the United States (U.S.). Although biological control agent development has been ongoing for many years to combat this invasive aquatic weed, the focus has now shifted towards the monoecious biotype because of apparent incompatibilities between previously intr...

Conservation of habitat fragments, including those embedded in an urban matrix which typically support fewer species than those in other landscape contexts, is important for combatting the global extinction crisis. Because urban avoiding species are often absent from habitat fragments within an urban matrix, studies of their distributions in these...

Interactions between invaders and resource availability may explain variation in their success or management efficacy. For widespread invaders, regional variation in plant response to nutrients can reflect phenotypic plasticity of the invader, genetic structure of invading populations, or a combination of the two. The wetland weed Alternanthera phi...

Urbanization dramatically modifies natural landscapes, fragments previously intact habitats, and is spreading rapidly, making it one of the leading causes of worldwide biodiversity decline. We studied the impact of urbanization on the occupancy of breeding birds in the Great Trinity Forest in Dallas, TX, the largest urban forest in the United State...

Texas horned lizards ( Phrynosoma cornutum ) have disappeared from many areas in Texas, especially from urbanized areas, probably in large part due to loss of suitable habitat. Our previous studies have found that horned lizards persist and occur at high densities in some small towns in southern Texas. Nevertheless, this species has continued to de...

Texas horned lizards ( Phrynosoma cornutum ) have disappeared from many areas in Texas, especially from urbanized areas, probably in large part due to loss of suitable habitat. Our previous studies have found that horned lizards persist and occur at high densities in some small towns in southern Texas. Nevertheless, this species has continued to de...

The southern US and northern Mexico serve as an ideal region to test alternative hypotheses regarding biotic diversification. Genomic data can now be combined with sophisticated computational models to quantify the impacts of paleoclimate change, geographic features, and habitat heterogeneity on spatial patterns of genetic diversity. In this study...

Schinus terebinthifolia is a problematic invasive alien plant (IAP) in South Africa that is a high priority target for biological control. Biological control has been implemented in the states of Florida and Hawaii (USA), where S. terebinthifolia is also an IAP. Phylogeographic work determined that there have been multiple introductions of two line...

The southwestern and central US serve as an ideal region to test alternative hypotheses regarding biotic diversification. Genomic data can now be combined with sophisticated computational models to quantify the impacts of paleoclimate change, geographic features, and habitat heterogeneity on spatial patterns of genetic diversity. In this study we c...

Texas horned lizards (Phrynosoma cornutum) have a number of ways to avoid predation, including camouflage, sharp cranial horns, flattening of the body, and the ability to squirt blood from the eyes. These characteristics and their relatively low survival rates in the wild suggest these lizards are under high predation pressure. These lizards have b...

There are increasing concerns regarding bat mortality at wind energy facilities, especially as installed capacity continues to grow. In North America, wind energy development has recently expanded into the Lower Rio Grande Valley in south Texas where bat species had not previously been exposed to wind turbines. Our study sought to characterize gene...

Peru is experiencing a “gastronomic boom” that is increasing the demand for seafood. We investigated two implicit assumptions of two popular sustainable seafood consumer-based initiatives: (1) seafood is labelled correctly, and (2) the recommended species are healthy for consumers. We used DNA barcoding to determine the taxonomic identity of 449 se...

The distribution of genetic diversity in invasive plant populations can have important management implications. Alligator weed ( Alternanthera philoxeroides (Mart.) Griseb.) was introduced into the United States around 1900 and has since spread throughout much of the southern U.S. and California. A successful biological control program was initiate...

Texas horned lizards (Phrynosoma cornutum) have a number of ways to avoid predation, including camouflage, sharp cranial horns, flattening of the body, and the ability to squirt blood from the eyes. These characteristics and their relatively low survival rates in the wild suggests these lizards are under high predation pressure. These lizards have...

Documentation of fine-scale plant genetic identity in order to match weed genotypes between native and invasive ranges can be used to identify potential biological control agents from target genotypes in the hopes that they will be better adapted and thus more effective once introduced into the exotic range. However, the utility of this information...

Bats are killed at wind energy facilities worldwide and we must improve our understanding of why this is happening and implement effective strategies to minimize impacts. To this end, we need accurate assessments of which individuals from which bat species are being killed at individual wind projects and at regional and range-wide scales. Tradition...

The life history and host range of the South American defoliator Paectes n. sp. (Lepidoptera: Euteliidae) was evaluated to determine its suitability for classical biological control of invasive Brazilian peppertree, Schinus terebinthifolia, in the U.S.A. The genus Paectes is well represented in both Florida and South America. We used DNA barcoding...

Recent efforts to discover insect biological control agents of the Brazilian peppertree, Schinus terebinthifolius (Anacardiaceae), include a new species belonging to a new genus, Spes schinella Metz, new genus, new species. We propose a hypothesis for placement of the new species among known Gelechiinae using the barcoding region of COI and targete...

Although the ultimate causes of high bat fatalities at wind farms are not well understood, several lines of evidence suggest that bats are attracted to wind turbines. One hypothesis is that bats would be attracted to turbines as a foraging resource if the insects that bats prey upon are commonly present on and around the turbine towers. To investig...

Insects identified in hoary bat stomach samples Insects identified in hoary bat stomachs collected from the Wolf Ridge wind farm in 2013 and 2014. Species identification is based on the percentage match in BOLD. Insects not identified to species are differentiated by letters. Insects identified in hoary bats collected in both years are indicated by...

Biweekly proportions of insect orders surveyed at turbine towers Biweekly averages and 95% CI of the proportions of each order collected during July–August malaise trapping in 2012, 2013, and 2015 at the Wolf Ridge wind farm. The “other” category includes Homoptera, Mantodea, Trichoptera, and spiders.

Insects identified in eastern red bat fecal pellets Insects identified in eastern red bat fecal pellets collected from the Wolf Ridge wind farm in 2011–2012. Species identification is based on the percentage match in BOLD. Insects not identified to species in BOLD are differentiated by letters. Insects identified in fecal pellets in >1 year are ind...

DNA sequences from insects found in eastern red and hoary bat stomachs

Sampling curves for insect species detected inbat stomachs and fecal pellets Sampling curve used to determine how many clones were needed to detect the insects in (A) bat stomach samples (n = 68 stomachs) and (B) bat fecal pellets (n = 23 fecal pellets) collected at wind turbines at the Wolf Ridge wind farm. The number above each data point indicat...

Detection frequency ofinsect species in bat stomachs and fecal pellets Detection frequency of each insect species in eastern red bat stomachs (n = 45), eastern red bat fecal pellets (n = 23), and hoary bat stomachs (n = 23) collected from the Wolf Ridge wind farm.

Insects identified in eastern red bat stomach samples Insects identified in eastern red bat stomachs collected from the Wolf Ridge wind farm in 2013 and 2014. Species identification is based on the percentage match in BOLD. Insects not identified to species in BOLD are differentiated by letters. Insects identified in eastern red bats collected in b...

DNA sequences from insects found in eastern red fecal pellets

Summary spreadsheets of all data (bat acoustic surveys, insect surveys, bat stomachs and fecal pellets)

Avian malaria is a common disease in songbirds, caused by protozoa in the genera Plasmodium, Haemoproteus, and Leucocytozoon. These parasites can negatively impact bird health, survival, and reproductive success. Four species of songbirds were sampled for blood parasites during the reproductive season; the American Redstart (Setophaga ruticilla), t...

The reasons why bats are coming into contact with wind turbines are not yet well understood. One hypothesis is that bats are attracted to wind turbines and this attraction may be because bats perceive or misperceive the turbines to provide a resource, such as a foraging or roosting site. During post-construction fatality searches at a wind energy f...

The marine otter (Lontra felina) can be found on rocky shores from the northern coast of Peru (9°S) to the extreme south of Argentina (56°S). This species is currently classified as endangered but there is little information on population size because marine otters are very difficult to observe and count. Between June and August 2012 we collected 2...

Bat fatality monitoring at wind turbines depends upon reliable identification of carcasses. Using reference mitochondrial cytochrome c oxidase I gene sequences mined from GENBANK and new sequences from collected samples, we constructed maximum likelihood trees including all 47 bat species found in the USA and tested the use of this locus for DNA ba...

Peru is strategically located in South America, sharing borders with Ecuador, Bolivia, Co- lombia, Brazil, and Chile, where the Rufford Foundation has supported over 400 projects (Peru 91, Ecuador 46, Bolivia 44, Colombia 89, Brazil 122, and Chile 56). Since many Rufford-supported projects are conservation-driven, we took this opportunity for grant...

A new species of Lygodactylus gecko (L. wojnowskii sp. nov.) is described from the vicinity of Chogoria Town on the eastern lower slopes of Mt. Kenya in central Kenya. A phylogeny based on mitochondrial and nuclear DNA shows that the proposed new taxon is distinct within the Lygodactylus picturatus group and is the sister lineage to L. mombasicus a...

Migratory tree bats comprise the majority of casualties at wind energy facilities across North America and some species, like Lasiurus borealis, are suspected to be in decline. We took advantage of the large numbers of L. borealis and L. cinereus salvaged during fall migration at 1 wind farm in Texas and 3 wind farms in Minnesota to evaluate the ab...

As bat populations are threatened by a range of factors, there is an increasing need to correctly identify and quantify the cumulative impacts of such factors to individual species. We have developed a fast and reliable method using the polymerase chain reaction to identify bat species from feces found near wind turbines at a north Texas wind farm....

Clonality and the mechanisms by which populations become established can affect the level and pattern of genetic diversity, which can in turn affect the ecology and evolution of those populations. We used amplified fragment length polymorphisms (AFLPs) to examine genetic diversity and clonality in four isolated populations of the rhizomatous pale p...

The safety of weed biological control depends upon the selection and utilization of the target weed by the agent while causing minimal harm to non-target species. Selection of weed species by biological control agents is determined by the presence of behavioral cues, generally host secondary plant compounds that elicit oviposition and feeding respo...

Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae) (hereafter Schinus), is one of the worst invasive species in Florida and Hawaii. The thrips Pseudophilothrips ichini Hood (Thysanoptera: Phlaeothripidae) is being considered as a potential biological control agent of Schinus. Two populations of this thrips were collecte...

We developed ten dinucleotide and four tetranucleotide microsatellite markers for two species of tree bats from the family Vespertilionidae that are experiencing high mortality at wind energy facilities. Eleven of these loci were polymorphic in eastern red bats (Lasiurus borealis), whereas nine loci were polymorphic in hoary bats (Lasiurus cinereus...

Native range and life history studies of an agent provide critical information during the early stages of a weed biological control programme. Brazilian peppertree is considered to be one of the worst invasive trees of Florida uplands because of negative environmental impacts and lack of effective long-term control methods. A potential biological c...

Surveys for biological control agents of the invasive weed Schinus terebinthifolius (Anacardiaceae) discovered two Omolabus weevils (Coleoptera: Attelabidae) feeding on the plant in its native range. Molecular and morphological analysis indicated that one of these species consistently fed on the target weed and the other species fed more broadly. A...

Brazilian peppertree ( Schinus terebinthifolius Raddi, Anacardiaceae) was introduced into Florida from South America in the 1800s and commercialized as an ornamental plant. Based on herbaria records and available literature, it began to escape cultivation and invade ruderal and natural habitats in the 1950s, and is now considered to be one of Flori...

Fragmentation is predicted to increase inbreeding depression and lower the evolutionary potential of organisms by disrupting dispersal. Trees may be more resilient to fragmentation effects due to potential long-distance dispersal mechanisms that genetically connect fragments. Polylepis woodlands in the high Andes are highly fragmented and are curre...

We developed a non-invasive DNA sampling method and 15 tetranucleotide microsatellite markers for Texas horned lizards (Phrynosoma cornutum). Swabbing the cloaca with a small cotton swab and preserving the cells in lysis buffer was an effective method to obtain tissue for DNA extraction. Loci were highly polymorphic with 8–25 alleles and observed h...

Phragmites are a tall, perennial, wetland grasses, occurring in both fresh and brackish waters. This 3-page fact sheet discusses the three genetic lineages: native, Gulf Coast, and Eurasian; and the threat posed to Florida ecosystems by an invasion of the exotic Eurasian type. Written by W. A. Overholt, R. Diaz, M. Hanson, and D. Williams, and publ...

Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), is a highly successful invasive species in the continental United States, Hawaiian archipelago, several Caribbean Islands, Australia, Bermuda, and a number of other countries worldwide. It also is one of only a few invasive intraspecific hybrids that has been well cha...

Brazilian peppertree, Schinus terebinthifolius Raddi, is a perennial woody plant native to Brazil, Argentina, and Paraguay that is recognized as one of the most invasive weeds in Florida. A new species of leaflet galling psyllid was discovered attacking Brazilian peppertree in Bahia, Brazil in March 2010. In this paper, a formal morphological descr...

Abstract How can successful invaders overcome reduced genetic variation via small founder population sizes to persist, thrive, and successfully adapt to a new set of environmental conditions? An expanding body of literature posits hybridization, both inter- and intraspecific, as a driver of the evolution of invasiveness via genetic processes. We st...

In Florida, air-potato is an invasive weed with high management priority, which may soon be targeted using classical biological control. This yam was introduced during the early 20th century by the United States Department of Agriculture (USDA) from areas throughout its extensive range. Our objectives were to characterize the genetic diversity of t...

Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), is a highly successful invasive species in the continental United States, Hawaiian archipelago, several Caribbean Islands, Australia, Bermuda, and a number of other countries worldwide. It also is one of only a few invasive intraspecific hybrids that has been well cha...

New this year – Because of restricted travel budgets to scientific conferences due to the bad economy, this newsletter has been expanded and now includes summaries of non-FWC funded invasive plant management research in Florida to help keep you apprised of the latest findings. In addition, because there is no current venue, or portal, for invasive...

Molecular and morphological evidence is presented to support the description of a second species of Pseudophilothrips from Brazil in association with Schinus terebinthifolius, an invasive weedy tree in North America. Pseudophilothrips is here recognized as a weakly defined genus comprising 13 described species from the Americas. This genus is presu...

A promising thrips, Pseudophilothrips ichini has been considered for biological control of the invasive weed Brazilian pepper Schinus terebinthifolius. Originally collected from southern Brazil where it was frequently found associated with significant damage to its host. Subsequently this thrips was introduced into quarantine in Florida to determin...

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Colu...