Behavioral ecologists generally agree that animals derive benefits from familiarity with spaces that they inhabit or visit, yet site familiarity is rudimentary or lacking in most models of habitat selection. In this review, I examine evidence for the occurrence of site familiarity and its fitness benefits, describe the difficulty of measuring site familiarity, note its omission from the influential ideal free and ideal despotic models, and use a literature search to test an assumption of the ideal models that has become widespread in habitat selection theory: that animals behave without regard for site familiarity. I find little support for such “familiarity blindness” in vertebrates. Next I discuss how the study of public information has drawn attention away from site familiarity and point out that both kinds of information are likely to be important in habitat selection. I proceed to examine current models of initial settlement (exploration and settlement of prebreeders on first territories) and optional resettlement (site fidelity or dispersal by established breeders following a period of prospecting) and find that the latter include only basic forms of site familiarity. Hence, I develop the concept that an inhabited space holds a unique “private value” to an animal based on its familiarity with the space and offer a simple model for optional resettlement based on private value that generates several novel predictions, including site fidelity based on cumulative breeding site familiarity and high site fidelity among species with complex territories.

Making habitat selection more “familiar”: a review

We studied patterns of annual movement of individual adult fire salamanders (Salamandra salamandra) during the years 2001 and 2002 in Western Germany in a typical middle European habitat for this species. We tested whether salamanders inhabit small home ranges and move little during the activity period as predicted for a species that shows strong site fidelity to a limited area. Initially, 98 individuals were collected in their natural habitat and marked with passive integrated transponder (PIT) tags. Of those individuals 88 were released at the collection site for recapture during the activity periods of the years 2001 and 2002. Ten marked individuals were kept in captivity to test for the tolerance of PIT tags. We did not find any negative impact of PIT tags on marked individuals of S. salamandra, neither under captive nor natural conditions. Forty-seven of the marked individuals (corresponding to 53% of the 88 released ones) were recaptured at least once and 28 individuals (corresponding to 32%) were recaptured multiple times. The return rate of males (78%) was higher than for females (43%). Mean home range size (and standard deviation) was estimated to 494 ± 282 m 2 for 4 individuals as the minimum convex polygon based on 5 to 6 recapture events for each individual per year and to 1295 ± 853 m 2 for 3 individuals with 8 records over two years. Minimum distances moved inferred from individual recaptures increased during the activity period of both years with time, indicating that individuals have more of a tendency to disperse than to stay within a limited area. Our data suggest therefore that S. salamandra adults display site fidelity, but use a much larger area than hitherto documented for this and other terrestrial salamander species.

/pdf/a-pit-tag-based-analysis-of-annual-movement-patterns-of-2627iie5a9.pdf

A PIT tag based analysis of annual movement patterns of adult fire salamanders (Salamandra salamandra) in a Middle European habitat

Semi-aquatic frogs are faced with an unusual locomotory challenge. They have to swim and jump using the same apparatus, i.e. the hind limbs. Optimization of two tasks that require mutually incompatible morphologies or physiologies cannot occur simultaneously. In such cases, natural selection will result in some compromise, i.e. an intermediate phenotype that can perform both tasks reasonably well, but its performance will never match that of a specialized phenotype. We found no direct evidence for a trade-off between jumping and swimming performance nor for a coupled optimization. This could be due to the importance of overall quality, as suggested by the fact that some frogs possess greater overall muscularity than others, irrespective of their body size. Another explanation could be that some morphological characteristics have a positive effect on both locomotor modes and others show a trade-off effect. The net effect of these characteristics could result in an overall absence of correlation between the two locomotor performances. Size has a great influence on the morphological data and on jumping performance, but not if performance is expressed as velocity. The body shape of an anuran is conservative and scales mostly isometrically.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7580.2007.00691.x

Morphological correlates of aquatic and terrestrial locomotion in a semi‐aquatic frog, Rana esculenta: no evidence for a design conflict

In organisms with determinate growth, sexual size dimorphism (SSD) occurs before maturity during the developmental process of growing apart, an ontogenetic perspective on the evolution of SSD. If the direction of SSD (female-larger SSD) is known, patterns of growth can be tested with one-tailed statistical distributions. In indeterminate growing organisms as well, does SSD occur before maturity? If it occurs, whether is females’ larger mean body size caused by a difference in age at maturity, age-specific size, divergent growth prior to maturity, or selection on post-maturational growth? How important is biphasic, sexual shape dimorphism (BSSD) for determinants of SSD? Biphasic characteristics are those that differ between adult aquatic- and terrestrial-phase morphs, and shape is size of a characteristic relative to body size. To address those questions, I determined age and body size based on a careful description of a growth trajectory for each sex in Salamandrella keyserlingii, using 555 independent data points from skeletochronological studies. Females reached maturity at 3–4 years of age, a year later than males that reached maturity at 2–3 years of age (mean body size: males = 57.63 mm, females = 61.70 mm; delayed sexual maturity resulted in SSD). However, SSD was highly detected before maturity (SSD index = 0.097), and females after maturity continued to grow and resulted in larger asymptotic size than males. Traits of BSSD were greater in males than in females. These results suggest that when determining SSD the difference in mean adult-body size results from the difference in age-specific size and the female-larger SSD develops to resolve intersexual ontogenetic conflict by allowing small-sized males to swell their whole body during the aquatic phase as much as large-sized females.

Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)

Habitat for wide-ranging species should be addressed at multiple scales to fully understand factors that limit populations. The marbled murrelet (Brachyramphus marmoratus), a threatened seabird, forages on the ocean and nests inland in large trees. We developed statistical relationships between murrelet use (occupancy and abundance) and habitat variables quantified across many spatial scales (statewide to local) and two time periods in California and southern Oregon, USA. We also addressed (1) if old-growth forest fragmentation was negatively associated with murrelet use, and (2) if some nesting areas are more important than others due to their proximity to high quality marine habitat. Most landscapes used for nesting were restricted to low elevation areas with frequent fog. Birds were most abundant in unfragmented old-growth forests located within a matrix of mature second-growth forest. Murrelets were less likely to occupy old-growth habitat if it was isolated (> 5 km) from other nesting murrelets. We found a time lag in response to fragmentation, where at least a few years were required before birds abandoned fragmented forests. Compared to landscapes with little tono murrelet use, landscapes with many murrelets were closer to the ocean's bays, river mouths, sandy shores, submarine canyons, and marine waters with consistently high primary productivity. Within local landscapes (≤ 800ha), inland factors limited bird abundance, but at the broadest landscape scale studied (3200 ha), proximity to marine habitat was most limiting. Management should focus on protecting or creating large, contiguous old-growth forest stands, especially in low-elevation areas near productive marine habitat.

Multi-scale landscape and seascape patterns associated with marbled murrelet nesting areas on the U.S. west coast

Current theory predicts that (1) locomotor performance of amphibians should exhibit greater thermal sensitivity in aquatic than in terrestrial habitats, and (2) amphibians lose the ability to acclimate locomotor performance to different temperatures after metamorphosis. To test these predictions for a semiaquatic plethodontid salamander (Pseudotriton ruber), I measured aquatic and terrestrial burst speeds of metamorphosed individuals at 8 C and 18 C after acclimation to 8 C and 18 C. Both aquatic and terrestrial speeds exhibited thermal sensitivity, which paralleled that for cycle frequency (tail or leg), but terrestrial speed had a significantly greater thermal sensitivity. Aquatic speed was significantly greater at 8 C acclimation, whereas terrestrial speed was not affected by thermal acclimation. Scaling of locomotor performance was significantly different in water than on land and was significantly affected by temperature. My results indicate that (1) aquatic burst speed has less thermal sens...

Aquatic and Terrestrial Locomotor Performance in a Semiaquatic Plethodontid Salamander (Pseudotriton ruber): Influence of Acute Temperature, Thermal Acclimation, and Body Size

Based on mark-recapture data collected over seven years on the salamander Plethodon kentucki, I examined (1) longevity and long-term site fidelity, (2) growth curves for each sex derived from both cross-sectional and longitudinal data on body size, (3) whether growth curves generated from the two kinds of data were comparable, and (4) how the relationship between adult body size and age in this species compares to that in other plethodontid salamanders. Recapture rates indicate that about 86% of males and 82% of females survived and remained in the study area from one year to the next. Most individuals recaptured at the end of the study period were within, or less than 2 m from, the home range they occupied at the beginning. Maximum age estimates were 13 yr for males and 16 yr for females. Growth curves derived from cross-sectional and longitudinal data were very similar. For both sexes, there is rapid growth up to the time of first reproduction (about 4 and 5 yr for males and females, respective...

Age, Growth, and Long-Term Site Fidelity in the Terrestrial Plethodontid Salamander Plethodon kentucki

Effects of acute temperature and thermal acclimation on aquatic and terrestrial locomotor performance of the three-lined salamander, Eurycea guttolineata

Previous studies revealed sexual dimorphism in terrestrial plethodontid salamanders of the genus Plethodon for greater snout–vent length (SVL) at first reproduction and maximum SVL in females, presence of a mental gland in males, larger vomeronasal organ (VNO) in males, and greater internarial width in males. Here I describe additional sexual dimorphism as well as seasonal (i.e., breeding versus non-breeding) dimorphism in Plethodon kentucki. I measured morphological variables on preserved specimens of adult individuals that were collected from Wise Co., Virginia during the breeding season (n = 26 females and 30 males) and non-breeding season (n = 29 females and 30 males). Residuals from regressions of morphological variables on SVL (all log10-transformed) and a principal component analysis on the residuals demonstrate that body mass, trunk length, and tail width are greater in females. These female features may be associated with selection for greater fecundity and increased fat storage to enhan...

Sexual and Seasonal Dimorphism in the Cumberland Plateau Woodland Salamander, Plethodon kentucki (Caudata: Plethodontidae)

Plethodontid salamanders within the genus Desmognathus range from species that are primarily aquatic to species that are fully terrestrial. Thus, these species are a good model system to use for a comparison of the effect of tail loss on maximal swimming and running performance, and propensity for caudal autotomy in closely related species that primarily inhabit either aquatic or terrestrial environments. I examined the effect of caudal autotomy on maximal swimming and running speeds in D. quadramaculatus (a larger, more aquatic species) and in D. ocoee (a smaller, primarily terrestrial species). Prior to tail loss, aquatic burst speeds were greater than terrestrial burst speeds for individuals of D. quadramaculatus, but the converse was true for individuals of D. ocoee. During aquatic locomotion in each species, burst speed was significantly reduced after autotomy. With the loss of about 65% of tail length, swimming burst speed declined about 50% for D. quadramaculatus and 40% for D. ocoee. Terrestrial burst speed was not reduced in either species after autotomy. These results show that tail loss is costly for primarily aquatic desmognathine salamanders in terms of a reduction in maximal locomotor performance. The time required for caudal autotomy increased significantly with body size in each species, and larger individuals of D. quadramaculatus would bite prior to autotomy. Thus, larger individuals of D. quadramaculatus may utilize caudal autotomy less readily and rely more on alternative antipredator mechanisms such as biting, and this may be related to a higher locomotor cost of autotomy for such individuals.

Glenn A. Marvin

Papers

Aquatic and Terrestrial Locomotor Performance in a Semiaquatic Plethodontid Salamander (Pseudotriton ruber): Influence of Acute Temperature, Thermal Acclimation, and Body Size

Age, Growth, and Long-Term Site Fidelity in the Terrestrial Plethodontid Salamander Plethodon kentucki

Effects of acute temperature and thermal acclimation on aquatic and terrestrial locomotor performance of the three-lined salamander, Eurycea guttolineata

Sexual and Seasonal Dimorphism in the Cumberland Plateau Woodland Salamander, Plethodon kentucki (Caudata: Plethodontidae)

Effect of Caudal Autotomy on Aquatic and Terrestrial Locomotor Performance in Two Desmognathine Salamander Species