Evolutionary approaches to conservation

I am interested in understanding how human-induced environmental stressors influence the behavioral ecology and fitness of animal populations, birds in particular. We blend approaches from evolutionary biology with conservation and ecology.

Current projects

• The influence of noise and disturbance on the fitness and breeding ecology of cavity nesting birds
• How land use change influences individual and population fitness of birds
• How avian community structure and ecology influences the spread of emerging infectious diseases, such as West Nile virus
• Captive rearing and rehabilitation
• The use of fluctuating asymmetry as an index of environmental stress

The influence of noise and disturbance on birds
Caitlin Kight is conducting a PhD project studying how quantifiable human disturbance and ambient noise levels affect the behavioral ecology and fitness of several species of secondary cavity nesting birds in our area. As part of William & Mary's 2004 REU site program in watershed ecology, two students - Bert Harris (from University of the South) and Jenny Phillips (from Lewis & Cark) - contributed greatly to this project by quantifying disturbance metrics at active nest boxes throughout local watersheds. So far, Caitlin has found that eastern bluebirds are fairly (pre-)adapted to intermediate disturbance levels, but that the predictability of disturbance is often an important parameter that many researchers do not measure. Caitlin is also starting to reveal some interesting among-species variation in fitness responses to disturbance, which may relate to the species history of contact with humans. We are currently working on a couple of manuscripts, and more will be available soon.

Caitlin has also started characterizing the spectral properties of ambient noise pollution in breeding territories of bluebirds and documenting how males may (or may not) adjust their vocalizations in response to the noise pollution. We are currently in the process of constructing a large sound map for all our bluebird breeding territories coupled with a genetic analysis of male fitness along a noise gradient. The genetic work is being led by Caitlin and Jake Sequeira, in collaboration with Margaret Saha.

Laura Page really sparked our interest in whether noise affects mating in birds by demonstrating, in lab conditions, that zebra finch pair bonds are weakened under high levels of environmental noise. A previous experiment by Lara McBride and Sabina Malhotra indicated that loud white noise promotes extra-pair preferences. However, Laura tested this explicitly and found that females are more likely to break their pair bond when noise pollution increases.

Josh Rellick followed up on Laura's study to investigate whether the pair-bond maintenance calls between male and female zebra finches is masked by ambient noise, and whether the birds have any capacity to adjust their vocalizations in noisy conditions.

Kelly Delaney is expanding these studies by performing a comparative analysis of how within-species variation in extra-pair paternity can be explained by environmental indicators of noise pollution.

Saji Perera performed a very interesting project investigating how ambient noise influences chick begging in eastern bluebirds. Her preliminary analyses indicate that the chicks do not increase their calling or shift the frequency of their calls in response to increasing noise - quite the contrary, they seem to quieten down. Eddie Devila-Reyes and Shenna Sikora analzyed whether the materials used to construct bluebird nest boxes affect the transmission of sound into and out of the box. So far they have found that some materials are better at blocking ambient noise and others seem to block chick and adult vocalizations. Therefore, the nest box materials will likely affect parent-offspring communication.

 

Land use, land cover, and fitness of birds
Prof. Dan Cristol's lab is continuing to collaborate with us on an ongoing assessment of whether conversion of land to golf courses provides adequate breeding habitat for a range of species. Several years of data indicate that eastern bluebirds are highly attracted to golf courses and raise many young there (perhaps more than at state parks and campuses). However, birds growing up on golf courses are in poor condition. It may be that golf courses are producing a lot of low quality individuals. There is more to come!

In a very related project, Judy Che and Rachel Biondolillo studied whether local box design features, landcover metrics, and landscape factors influence the breeding success of these bluebirds. Judy presented a preliminary poster at the Animal Behavior Society conference in Mexico in 2004, and you can view her poster here. Rachel has extended this study to include more years of breeding date. So far, their data indicate that all three levels (box, local environment, and landscape) can significantly affect the success of the birds.

In summer 2006, Pacifica Sommers and Louise Gava took the land cover analyses a step further and used GIS to investigate relationships between impervious surface cover, direct disturbance measurements in the environment, and the fitness of secondary cavity nesting birds. Their data indicate that GIS metrics can predict local disturbance regimes and fitness variation in a neotropical migrant, the house wren.

Charles Johnson and Lori Simpers investigated whether bluebird breeding and chick growth and condition are influenced by soil quality. As adult birds feed their nestlings insects from the ground near the box, we hypothesized that poor soil quality around the nest box may detrimentally affect the fitness of chicks. Evidence to date indicates that soil quality has very little influence on chick growth and fitness. However, Lori collaborated with Tondra Robinson to indicate that nutrient content (Carbon:Nitrogen:Phosporous) ratios in food items and the efficiency with which chicks process these nutrients both relate to chick growth and fitness. In a follow-up to Tondra and Lori's pattern, Ashley Pearce just completed an experimental study to show that the fattest and fastest growing chicks in a brood are those that can extract the most Nitrogen from their food. Therefore, among-individual differences in physiology may explain the growth differences you seen among chicks within the same brood (i.e., it's not all differential feeding from parents, which is the traditional explanation).

 

Avian community structure and human health
Stavros Calos recently completed an intriguing project investigating whether avian diversity is related to the risk of humans contracting West Nile virus. Our analyses, published in PLoS ONE, indicate that avian community structure can explain as much as 50% of the variation in human West Nile cases in the eastern US. In particular, Stavros found that counties with greater avian diversity have a much lower incidence of human West Nile infection. In other words, bird diversity can help buffer humans against infectious disease.

We are interested in following up to see if avian community structure in general dillutes the human risks from this and other avian emerging infectious diseases. We are also interested in how avian host behavioral ecology and life history plays a role in the spread of infectious diseases.

 

Captive rearing and rehabilitation
In a very applied project, Becky McKeel is documenting the ontogeny of aggressive/submissive behaviors in grey wolf pups being reared in captivity. Becky works at Busch Gardens Williamsburg and is leading the team who are trying to introduce wolf pups into an established pack. This has never been tried before. As part of her Masters research, Becky will be comparing the behavioral responses of the captive wolves to natural situations of pups joining packs in the wild. The hope is to design better introduction and rehabilitation practices for large endangered canids.

 

Fluctuating asymmetry as an index of environmental stress
Fluctuating asymmetry is the manifestation of poor development. As each side of the body grows and if genetic and/or environmental conditions are poor, organisms grow-up to be more asymemtric (i.e. they have measurable difference between the left and right side of the body).

Jenny Phillips completed a project with salamanders to investigate whether fluctuating asymmetry can be used as bio-indicator of habitat quality in amphibians. She compared salamanders from pristine and impacted streams around Lake Matoaka (the lake in the middle of our campus). This project follows up on an Honors project by Melissa Pensa, which indicated that salamanders from a stream of poor water quality were significantly more asymmetric than those from a more pristine stream. Jenny's data indicated that salamanders from the impacted streams are under-developed and have a greater frequency of gross abnormalities. However, they are NOT more asymmetric.

Melissa Kennedy investigated whether hybrids of two species of shrew experience sufficient genetic stress to increase fluctuating asymmetry. This is an interesting case, as there is some evidence that some of the hybrids are viable and have bred back in to both parental populations. Preliminary analyses indicate that hybrids are not more asymmetric!