
Don ForesterTowson University | TU · Department of Biological Sciences
Don Forester
Doctor of Philosophy
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40
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Introduction
Publications
Publications (40)
A common mesofilter approach to conservation of biological diversity and ecosystem function used in agricultural and urban landscapes is maintenance of wetlands and an undisturbed terrestrial buffer surrounding wetlands. Although it is generally accepted that forest buffers protect wetland‐associated biological diversity and ecosystem function, the...
Although amphibians use human-created habitats in urban landscapes, few studies have investigated the quality of these habitats. To assess habitat quality of stormwater management ponds and adjacent urban uplands for wood frogs (Lithobates sylvaticus) and American toads (Anaxyrus americanus), we compared life history characteristics between populat...
Predator avoidance behaviour has been observed in many species and can strongly affect trophic interactions. Animals frequently adjust their response to predators in proportion to risk; however, when they are exposed to chronic predation risk, some animals reduce their antipredator responses in favour of resource acquisition. Animals that are subje...
Territorial disputes are frequently settled by an advantage afforded to one of the contestants by asymmetries such as size difference, strength and motivation. Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus) are reported to defend cover objects, a form of territorial behaviour. We conducted an experiment to determine whether or not...
Adult red-spotted newts, Notophthalmus v. viridescens, were collected from an aquatic habitat and released on land in an arena 20 m from the shore of their home pond. Freshly captured, untreated newts exhibited significant orientation toward the pond. Positive orientation was also observed when solar cues and pondside landmarks were hidden and when...
In Maryland, the wood frog, Rana sylvatica, oviposits in ephemeral ponds and pools during early spring. Seasonal precipitation is often unpredictable and egg masses may become exposed as ponds recede. The ability of wood frog eggs to withstand prolonged terrestrial exposure was tested in the laboratory. Egg mortality rate was exponential. Compared...
Adult males and females of Desmognathus ochrophaeus were tested in two-choice substrate discrimination trials in which salamanders were given a choice of the marked substrates of opposite-sex individuals from their own population and from a geographically distinct population. Females exhibited a significant preference for the marked substrates of e...
We conducted a comparative investigation of nest relocation and egg recognition by four species of streamside salamanders indigenous to eastern North America: Seepage Salamander (Desmognathus aeneus), Santeetlah Salamander (Desmognathus santeetlah), Ocoee Salamander (Desmognathus ocoee), and Northern Dusky Salamander (Desmognathus fuscus). Females...
We sampled the larvae of a rare streamside salamander, Eurycea junaluska, across a range of stream sizes to determine habitat use patterns at both reach (75-m length of stream) and watershed scales (i.e., the network of streams draining fourth-order watersheds and their relationship to the larger river channels). An information-theoretic approach t...
We sampled the distribution of northern dusky salamander (Desmognathus fuscus) nests at randomly selected 15 m stream reaches throughout a third-order watershed in eastern Maryland. Our goal was to investigate the distribution of nests in relationship to physical habitat variables at three spatial scales: (1) watershed, (2) reach (15 m of stream),...
The establishment of polyploid populations involves the persistence and growth of the polyploid in the presence of the progenitor species. Although there have been a number of animal polyploid species documented, relatively few inquiries have been made into the large‐scale mechanisms of polyploid establishment in animal groups. Herein we investigat...
The distribution of wetland breeding amphibians may be influenced by multiple habitat variables interacting at various scales.
We applied a multi-scaled modeling approach to relate the presence and absence of carpenter frogs (Lithobates virgatipes), a species of conservation concern in Maryland, to several wetland and landscape characteristics. We...
While many amphibians have complex life cycles involving a primarily terrestrial adult phase and an aquatic larval phase, use of terrestrial habits by adult forms remains poorly understood. We used radiotelemetry to track the post-breeding dispersals of 16 female Bufo americanus during the summer and fall of 2001 to determine the extent of upland h...
We conducted behavioral trials to determine if egg preference by female northern dusky salamanders (Desmognathus fuscus) is influenced by the developmental age of their eggs. Within 72 h of oviposition,we divided 41 clutches in half and monitored the time the female spent with each of the genetically similar half-clutches. We then reared the eggs f...
Egg brooding behavior is typical in plethodontid salamanders, and in most species females attend their eggs from oviposition until hatching (Crump, 1995). Attendant behavior has been shown to increase egg survival in the field (Forester, 1979a;Harris et al., 1995), and it has been specifically demonstrated to reduce susceptibility of eggs to predat...
The redback salamander, Plethodon cinereus, is indigenous to the woodlands of eastern North America, from southern Canada south to North Carolina (Conant, R., and J. T. Collins. 1998). Over much of its range it is quite numerous(e.g.,2.8salamander/m2 in Giles Co., Virginia; Mathis, 1991), often representing a major component of the vertebrate bioma...
1. Toads comprising the Towson population are characterized by a prolonged breeding season (> 5 weeks), and some males remained at the site for at least 23 days. 2. During the breeding season, sexually active males may be classified as terrestrial or aquatic. 3. Although we did not observe males switching tactics during the same calling session, we...
Egg guarding, or `brooding', by the mountain dusky salamander
(Desmognathus ochrophaeus) is an example of maternal behaviour that can
be experimentally manipulated and described quantitatively. It has been
demonstrated that females of this species can specifically recognize,
and will preferentially brood, their own eggs over those of a
conspecific....
Each of 32 male, Dendrobates pumilio (red phase) were allowed to establish a territory in one half of a 40 liter aquarium. Each enclosure contained a substrate of Sphagnum, a pelted plant, and a water dish. Males occupying the same aquarium were prevented from seeing one another by an opaque barrier. In the first experiment, residents were presente...
1. Male spring peepers exhibit individual variation in calling persistence within as well as between nights. 2. Weather conditions influence nightly variation in calling persistence throughout the reproductive season, but there is a pronounced decrease in calling persistence late in the season which appears to be independent of climate. 3. In four...
1. Male spring peepers respond to acoustic interference from an encroaching conspecific with a graded behavioral sequence: they increase their call repetition rate, they emit one or more encounter calls, they entrain their calls to those of the intruder. 2. Once entrained, males continue to call synchronously for extended periods. 3. The time inter...
Non-calling satellite males were observed throughout the reproductive season in a breeding chorus of spring peepers. The frequency of this alternative reproductive strategy increased with chorus density, but did not exceed 14%. Satellite males were significantly smaller than calling males with which they associated. Mating success among males did n...
The mountain dusky salamander (Desmognathus
ochrophaeus Cope) is a small plethodontid (snout-vent length = 30–40 mm), indigenous to the Appalachian highlands of eastern North America. At low elevations, the species inhabits moist microhabitats associated with stream margins and seepages; at high elevations, the species exhibits pronounced terrestri...
1. The advertisement call of the spring peeper exhibits significant variation in each of the four parameters examined: intensity, duration, frequency, repetition rate. 2. In playback experiments involving calls differing in a single parameter, females exhibited preference for loud calls, calls with a rapid repetition rate and low frequency calls. 3...
The Desmognathus ochrophaeus female decreases clutch desiccation by reducing the exposed surface of her egg mass. -from Author
The ability of female mountain dusky salamanders to recognize their own egg mass following experimental isolation ranging from 0 to 96 h was tested in the laboratory. Egg recognition and clutch fidelity did not differ between isolation groups, nor was it affected by the number of days that a female had been attending her eggs. Females with developm...
Gravid females frequently become associated with a potential nesting site well in advance of oviposition. During the reproductive season, females reduce their foraging and become generally less active. Nutritional intake is greatly reduced and results in a significant decrease in dry body weight as compared to male controls.
Field observations indicated that egg clutches attended by Desmognathus ochrophaeus Cope females were less susceptible to predation than were unattended clutches. Clutches deprived of females but protected from predation usually succumbed to phycomycete fungi within 12 days. Susceptibility of unattended eggs to fungal infestation was negatively cor...
Confrontations were staged in the laboratory between attending (brooding) female salamanders and known or suspected predators. Females successfully defended their eggs against conspecific predators of various age and sex classes, and against ground beetles, but were not as successful against large heterospecific salamanders and ringneck snakes. A q...
A photographic, mark-recapture study of the Blue Ridge dusky salamander, Desmognathus ochrophaeus, revealed that at least some females oviposit during the spring and summer on an annual basis. Females exhibited a propensity for the same segment of the reproductive habitat during successive years. The adaptive value of this behavior is discussed.
Scaphiopus bombifrons and S. hammondii are closely related species displaying sympatry in northwestern Texas. In the laboratory the two species backcross, and an attempt has been made to determine the reproductive isolating mechanisms functioning between them. Spectrographic analysis of the mating calls from eight localities near Lubbock, Texas, in...