2001 Grad Symposium

Ecology and Evolutionary Biology
11th Annual Graduate Student Symposium

Schedule: Click on the author's name to view abstract

9:00	Fred Maryanski, Vice Chancellor	Opening remarks
9:15	Michael Moody	Phylogenetic relationships among Haloragaceae emphasizing the aquatic genus Myriophyllum
9:30	Gaines Tyler	Site specificity, mode of attachment and histopathogenicity of Calliobothrium (Cestoda: Tetraphyllidea) from Mustelus lenticulatus (Elasmobranchii: Carcharhiniformes)
9:45	Robert Dunn	Down the tunnels of ants - ants and seeds in young secondary forests
10:00	Michael Wall	Assessing the conservation impact of climatic variability on the pollination of a federally endangered plant, Clematis socialis Kral
10:15	Break
10:30	Tom Rombdal	Testing the effect of geometric boundaries on one-dimensional species distributions on continental and local scale
10:45	Colin Young	Ethonobotanical uses of plants among Creoles of north central Belize
11:00	Derek Sikes	Beetles of Block Island: rare species that once occurred on the mainland
11:15	Jose Peirera	Abundance and distribution of juvenile tautog (Tautoga onitis) and cunner (Tautogolabrus adspersus) in Morris Cove
11:30	Neva Hax	Systematics of the Bryoxiphiaceae (Bryophyta)
11:45	Noah Gordon	The effects of feeding on the territorial behavior of the green frog, Rana clamitans
12:00	Lunch
1:00	Roland de Gouvenain	Niche partitioning among four Malagasy tree species
1:15	Nancy LaFleur	Birds, invasive plants and seed dispersal
1:30	Jen Martin	Early life history of the sand whiting (Sillago sihama) from the Tanshui Estuary, Taiwan, as revealed by otolith microstructure and microchemistry
1:45	Tracy Gartner	Mixed-litter decomposition on calcareoius and acidic soils in northwestern Connecticut
2:00	Break
2:15	Gregor Yanega	The bill, the bug, da bomb: what drives variability in hummingbird foraging behavior?
2:30	Florian Reyda	A comparison of biological performances among a laboratory-isolated and two wild populations of Moniliformis moniliformis
2:45	Jon Richmond	Prey selection in horned lizards following the invasion of argentine ants in southern California
3:00	Justin Schaefer	Allometry of age and somatic energy storage in the fathead minnow, Pimephales promelas

Abstracts:

de Gouvenain, Roland
Niche partitioning among four Malagasy tree species
Niche partitioning of forest environments resulting from species life-history trade-offs in resource utilization has been hypothesized as a major cause of landscape-level forest composition heterogeneity for both temperate and tropical forests. The alternative "Nonequilibrium Model" of tropical forest beta-diversity, in which all tree species are adaptively equivalent and variation in species composition is the result of purely stochastic "lottery" processes has been supported by some studies and rejected by others. Species-specific tradeoffs between survivorship and growth across gradients of light and soil moisture were studied with 1200 planted seedlings of four tree species over the course of two years. Functional responses to light and soil moisture gradients differed among the four species, resulting in partitioning of the resource space. Even if the present spatial pattern of resource gradients is only transitory, this environmental partitioning among different species of seedlings could promote the long-term coexistence of the four species within a forest.

Dunn, Robert
Down the tunnels of ants - ants and seeds in young secondary forests
In many regions of the world, urban migration, combined with the local or regional exhaustion of the land has led to the large-scale abandonment of pastoral and agricultural lands. As is ture now in the U. S., these regenerating forests will play an important role in the future as they grow into mature forest. Nonetheless, we understand relatively little about the ecology and dynamics of regenerating forests. Using my data from secondary forests in Bolivia, Costa Rica and Peru, I examine the effects of forest regeneration on ant communities, focusing on changes in the abundance and foraging efficiency of ants. I have found ant abundance and foraging efficiency to be consistently higher in young secondary forests than in mature forests. Preliminary data indicates this may have had a large impact on seedbed dynamics. Depending upon what happens to seeds removed by ants, this elevated ant abundance could have a long-term impact on both the dynamics and composition of regenerating and eventually mature forests. This contrasts dramatically with the effects of ants in forest gaps.

Gartner, Tracy
Mixed-litter decomposition on calcareous and acidic soils in northwest Connecticut
Leaf litter decomposition research has primarily focused on single-species, although leaves do not segregate neatly in forests. Litter mixes also change as forest composition changes over time. Is decomposition of a litter mixture predictable from knowledge of the component species? Or do litters of different species interact? This study in northwestern Connecticut examined the decomposition of Quercus rubra (red oak), Acer rubrum (red maple) and Acer saccharum (sugar maple). Often associated together both on calcareous and acidic soils, these common species have leaf litter that ranges from low to high quality. Leaves were collected during peak litterfall in 1999 from two calcareous and two acidic sites. A total of 420 fiberglass-mesh litterbags with each species individually and all possible mixtures were placed at the sites of origin in December, 1999. Mass and C and N content were monitored every three months over the course of a year. At all four sites, carbon and mass were correlated and fit Olsen's (1963) exponential decay model, while N increased initially before declining. Litter tended to decompose faster than expected in mixture with the greatest increase in the sugar maple/red oak mixture two species most in different litter quality; effects were greater on calcareous soil than on acidic soil. These results indicate that heterogeneity of leaf litter could have significant impacts on nutrient cycling in forests.

Gordon, Noah
The effects of feeding on the territorial behavior of the green frog, Rana clamitans
Green frogs, Rana clamitans, are large ranid frogs found in permanent wetlands throughout most of the eastern United States. These frogs exhibit a resource defense mating strategy whereby males advertise for mates and defend territories along the shoreline. The breeding season of green frogs in the northeastern U. S. extends from late May until August. During the breeding season male frogs engage in territorial defense for up to several weeks. Because the arrival date of females to breeding choruses is unpredictable, males should defend territories for as long as possible to maximize their chances of reproductive success. Previous research has shown that male green frogs markedly reduce their intake of food and have limited stores of glycogen and lipids during the breeding season. Glycogen and lipids are known to be major sources of energy for fueling chorus activity in other species of frogs. Based on this information, I hypothesized that male green frogs may be energy limited during the breeding season. Specifically, I tested the hypothesis that males provided with extra food will 1) have longer tenures on territories, 2) expend more energy in calling and territory defense, and 3) show reduced movement between territories (because of greater site specificity). I tested these hypotheses by supplementally feeding frogs in a common garden type experiment and by conducting regular surveys of frog location and behavior over the course of the breeding season. My results do not support the first two hypotheses, however, the third hypothesis was supported. This suggests that green frog males reduce foraging rather than increasing activity when food resources are more abundant.

Hax, Neva
Systematics of the Bryoxiphiaceae (Bryophyta)
The Bryoxiphiaceae is a family of mosses composed of one genus, Bryoxiphium, accommodating 2 to 5 taxa. I am undertakihng a taxonomic revision of this family. First, I will draw taxonomic hypotheses based on variation in morphological characters. Subsequently, the hypotheses of monophyly will be tested using molecular characters (i.e. nucleotide sequences of the nuclear and chloroplast genome). These data will also be used to clarify the phylogenetic relationships of Bryoxiphiaceae to other moss families. The ordinal classification of mosses rests on the structure of the peristome, the ring of teeth surrounding the opening of the sporophyte. The Bryoxiphiaceae lack a peristome and phylogenetic affinities have remained obscure due to its patristically derived gametophyte.

LaFleur, Nancy
Birds, invasive plants and seed dispersal
The dispersal of plant seeds by animal ingestion benefits both seed producers and dispersers. Non-native species, both plant and animal, which fit into established dispersal systems not only have the potential to expand upon their own successes, but may also alter the population dynamics of associated plants, both native and introduced. In order to understand the effects of invasives in an avian seed dispersal system in Connecticut, I monitored use of the fruits of four species of invasive plants at 6 sites starting in October and continuing throughout the fall and winter. I will present preliminary results from this field work.

Martin, Jennifer1, C. W. Chang, S. K. Lu, Wann-Nian Tzeng2, and Yoshi Iizuka3
1 Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT
2 Department of Zoology, National Taiwan University, Taipei, Taiwan
3 Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
Early life history of the sand whiting (Sillago sihama) from the Tanshui Estuary, Taiwan as revealed by otolith microstructure and microchemistry
Early life stages are a crucial period in determining the year-class strength of marine fish stocks. Growth rates affect survival and the subsequent recruitment into the adult population by varying the stage duration over which high mortality may operate. For species that are estuarine-dependent, such as the sand whiting, it is beneficial to reduce time spent in pelagic larval stages and increase time spent in highly productive estuarine nursery grounds. The objectives of the present study are: 1) understand estuarine recruitment and seasonal dynamics of early life history stages of S. sihama in the Tanshui; 2) relate ontogenetic (metamorphosis and settlement) and habitat transitions (ocean to estuary); 3) use microchemical analysis to reconstruct the salinity history of individuals. Estuarine arrival occurred from March to November 1998 with a peak in July. Estuarine recruitment is primarily by the presettlement juvenile stage and appears to be length dependent. Recruitment is also related to growth rate with faster growing individuals arriving at younger ages. Results of microchemical analysis of post-settlement individuals entering the estuary revealed that a portion of the population delayed estuarine recruitment and used coastal waters as nursery grounds. It appears that settlement and nursery locations are variable in this population and that the timing of these transitions are not necessarily linked.

Moody, Michael L. and Donald H. Les
Phylogenetic relationshiops among Haloragaceae emphasizing the aquatic genus Myriophyllum
Phylogenetic analyses using parsimony and maximum likelihood methods with data from the plastid genome (rbcL, matK and trnK introns) were conducted to assess the relationships among Haloragaceae genera and among species in the aquatic genus Myriophyllum. The Haloragaceae consist of 8 genera, three of the genera are aquatic. Myriophyllum consists of approximately 40 species with the greatest species diversity centered in Australia. Relationships among many aquatic plants have been notoriously difficult to assess due to their convergent and highly plastic vegetative morphology and reduced flower size. All of these factors have made it difficult to determine species limits and relationships among Myriophyllum. MatK, rbcL and the trnK introns have been surprisingly informative in delimiting relationships among Haloragaceae genera and among species of Myriophyllum. Results suggest an Australian origin for the family with the potential for multiple origins of the aquatic habit. Results also suggest two well supported clades in the Myriophyllum. A clade of North American endemics (Schindler's subgenus Tessaronia) is well supported). Current data support a monophyletic Myriophyllum. Future work will focus on the evolution of phenotypic plasticity in the "North American" clade using phylogenetic hypotheses developed here.

Pereira, Jose J.1, Paul Clark1, and Ronald Goldberg1
1 National Marine Fisheries Service, Northeast Fisheries Science Center, Milford Laboratory, 212 Rogers Avenue, Milford, CT
Abundance and distribution of juvenile tautog (Tautoga onitis) and cunner (Tautogolabrus adspersus) in Morris Cove
Morris Cove, on the eastern side of New Haven Harbor, is an important nursery area for both tautog and cunner juveniles. Monthly beach seine samples at 10 sites in Morris Cove were initiated in May of 1998 to assess temporal and spatial distribution of near shore fishes. Beginning in July of 1999, tautog were tagged with coded wire tags to assess habitat fidelity, measure individual growth rates, and estimate the juvenile tautog population in the cove. The patterns of appearance in the beach seine hauls were similar for both species and both years. Tautog or cunner first appeared in samples in May or June and young-of-the-year appeared in July. Peak abundance occurred in July and August and both species disappeared from samples in October or November. Distribution of both species was not uniform along the beach, with more fish found at the cobble areas of the beach than the sandy areas. Macroalgal density along the beach also varied with site. Two sites at opposite ends of the sampling area seemed to produce the most vegetation, but only the sites that included a cobble substrate produced large numbers of fish. The cobble substrate also provided attachment for the macroalgae that was not availble on the sandy substrate at the other end of the beach. Here the macroalgae was present as drifiting mats. The tautog and cunner may have found that the more complex habitat provided by the cobble and the attached macroalgae more attractive than the drifting algal mats. Almost 600 tautog were capture in the 1999 beach seining effort. The majority of these fish were less than 100 mm in total length indicating that this area is a nursery area for fish age 0 and 1. Tautog may leave this area as a result of an ontogenetic shift in food requirements. Only 295 of the tautog captured in were large enough to mark with coded wire tags. A total of 10 were recaptured. Most recaptures occurred in the same section of the beach where the fish had first been captured and tagged. Days-at-liberty ranged from one to 43 days. A population estimate based on these recaptures places the number of tautog in the cove large enough to be tagged at approximately 4000 and by inference, the total population at about twice that number. A similar beach seine study of Morris Cove was conducted in 1942 and > 43 (Warfel and Merriman, 1944). In contrast to our study, Warfel and Merriman report the capture of only 14 tautog and 1 cunner in their entire one-year study. We hypothesize that changes in the habitat since 1944 may account for this difference. In 1944 Morris Cove was a gently sloping sandy beach. Since then, the building of small breakwaters in the middle and at the southern end of the cove, mining of the cove for sand and gravel for highway construction, and dredging of the harbor channel have led to the net transport of sand out of the cove leaving behind cobble. The replacement of the sand substrate with cobble may have provided essential habitat, preferred by the tautog and cunner.

Reyda, Florian
A comparison of biological performances among a laboratory-isolated population and two wild populations of Moniliformis moniliformis
Divergence of biological performance of a laboratory-reared population of Moniliformis moniliformis (Acanthocephala) was investigated after 31 years, or approximately 60 generations, of genetic isolation. An isolate of the laboratory-reared population and isolates of two wild populations were used to begin 3 independent life cycles that were maintained for 1 generation for interbreeding and life history

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