James R Spotila

Drexel University | DU · Department of Biodiversity, Earth and Environmental Science

The current climate warming is a challenge to biodiversity that could surpass the adaptation capacity of some species. Hence, understanding the means by which populations undergo an increase in their thermal tolerance is critical to assess how they could adapt to climate warming. Specifically, sea turtle populations could respond to increasing temp...

Thermal conditions in the nest affect the development of sea turtle clutches, with high temperatures potentially reducing reproductive success and the quality of hatchlings. In a warming climate, increasing temperatures could become a threat to sea turtles in many locations. This has prompted the implementation or recommendation of climate mitigati...

Physiological indexes like blood parameters have been widely used to monitor the health of free-roaming animals. Attempts to reintroduce one of China’s most endangered species, the giant panda (Ailuropoda melanoleuca), have been hampered by a lack of data on its ecology and physiology. We examined three giant pandas’ hematological and blood chemist...

We investigated methods for reducing highway-caused mortality of Mojave Desert Tortoises (Gopherus agassizii) using barriers at the Desert Tortoise Conservation Center, located near Las Vegas, Nevada. Experiments tested effectiveness of various barriers of different heights and made of different construction materials, sex-dependent behaviors inclu...

In a study to reduce Mojave Desert Tortoise (Gopherus agassizii) mortality along roadways, we tested the feasibility of structures that discourage tortoises from 1) walking or ''pacing'' along barriers or 2) crossing areas where gates or openings occur. The diversion designs we tested (one straight and one curved structure, each 7.6 m long) deflect...

Knowledge of energy expenditure informs conservation managers for long term plans for endangered species health and habitat suitability. We measured field metabolic rate (FMR) of free-roaming giant pandas in large enclosures in a nature reserve using the doubly labeled water method. Giant pandas in zoo like enclosures had a similar FMR (14,182 kJ/d...

The American black bear (Ursus americanus) was long thought to be solitary and its social organization has not been well described. Here we present new data on black bear social structure. The objectives of the study were to make detailed observations of the behavior of wild black bears to determine their social interactions and structure. We teste...

Sea turtles nest on tropical and subtropical beaches, where developmental success of egg clutches depends on nest temperature. Higher nest temperatures increase embryo and hatchling mortalities and produce female hatchlings. Nest shading has been used on some beaches to reduce nest temperatures, and thereby increase number of hatchlings and reduce...

To maximise reproductive fitness, species make trade-offs among reproductive traits, e.g., offspring quantity vs. offspring size, within energetic, anatomical, and physiological constraints. Sea turtles are a model taxon to study reproductive trade-offs, because they lack parental care and because there are strong selective pressures on hatchlings...

The adaptive significance of temperature-dependent sex determination (TSD) in reptiles remains unknown decades after TSD was first identified in this group. Concurrently, there is growing concern about the effect that rising temperatures may have on species with TSD, potentially producing extremely biased sex ratios or offspring of only one sex. Th...

Giant pandas (Ailuropoda melanoleuca) were historically hunted using dogs and are currently threatened by free-roaming dogs and their associated diseases. To better understand the spatial magnitude of this threat, we used a GIS approach to investigate edge effects of dogs on giant panda habitat. We first examined two nature reserves with contrastin...

Failure to improve the conservation status of endangered species is often related to inadequate allocation of conservation resources to highest priority issues. Eastern Pacific (EP) leatherbacks are perhaps the most endangered sea turtle population in the world, and continue on a path to regional extinction. To provide coherent, regional conservati...

Marine turtles often conduct extensive migrations from foraging to breeding habitats. Turtles may spend several months in these breeding habitats, while periodically taking brief excursions onto terrestrial environments to nest. Identification and protection of these breeding habitats over the duration of the reproductive season is therefore vital...

The potential threat of domestic dogs to wildlife habitat in China is not widely recognized, despite their large population, lack of regulations regarding their control, and threat they pose to native species. In a case study, we surveyed villages surrounding Liziping Nature Reserve, the primary site for the release of captive‐born giant pandas (Ai...

The internesting interval separates successive clutches of sea turtle eggs, and its duration varies both among and within species. Here, we review the potential physiological limits to this interval, and develop the hypothesis that desalination capacity limits the internesting interval owing to the requirement for water deposition in eggs. Sea turt...

Sea turtles bury their eggs in nests at depths ranging from 25 to 100 cm. After hatching, turtles crawl up to the surface and emerge over several days. Some hatchlings fail to emerge and die in the sand column. In this study, we investigated the effect of the depth of the drying front (the region separating saturated and partially dry sand), number...

Our studies using American alligators, Alligator mississippiensis , green turtles, Chelonia mydas , and leatherback turtles, Dermochelys coriacea , have provided insights into the physiology of large extant and extinct reptiles. Respiratory and metabolic physiology studies indicate that many living large reptiles exhibit heat conservation adaptatio...

Leatherback turtles (Dermochelys coriacea) have declined dramatically in the eastern Pacific Ocean (EP) in recent decades. Traditionally, population assessments have relied on the numbers of turtles on the beaches with the highest abundance of turtles (index beaches) and often disregarded the importance of nesting beaches with smaller, but still re...

Small-scale fisheries are responsible for high numbers of animals caught as bycatch, such as turtles, cetaceans, and seals. Bycatch and its associated mortality is a major conservation challenge for these species and is considered undesirable by fishermen. To gain insights on the impact of bycatch on small-scale fishermen and put it in context with...

Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his “Why mountain passes are higher in the tropics” that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stabilit...

Normalized mean hatching success versus mean temperature (°C). Mean hatching success of green, olive ridley and leatherback turtle clutches versus mean incubation temperature (°C) by 1 (°C) increments. Data were normalized at 30°C to facilitate comparison between the three species. (PDF)

The red panda (Ailurus fulgens) has a similar diet, primarily bamboo, and shares the same habitat as the giant panda, Ailuropoda melanoleuca. There are considerable efforts underway to understand the ecology of the red panda and to increase its populations in natural reserves. Yet it is difficult to design an effective strategy for red panda reintr...

Adult North American tortoises (Gopherus spp.) engage in aggressive interactions with conspecifics when competing for mates and burrows. However, aggressive interactions have not been widely reported in hatchling and juvenile tortoises. We describe aggressive interactions between wild hatchling and juvenile gopher tortoises (Gopherus polyphemus) ba...

Playa La Flor in Nicaragua is one of the few remaining beaches where Olive Ridley Sea Turtles (Lepidochelys olivacea) nest in arribadas. In this study, we present data on the status of the nesting population of L. olivacea on Playa La Flor from 1998 to 2006. Furthermore, in 2004 we established six plots (6 m × 6 m) on a 400-m section of the nesting...

Playa La Flor in Nicaragua is one of the few remaining beaches where Olive Ridley Sea Turtles (Lepidochelys olivacea) nest in arribadas. In this study, we present data on the status of the nesting population of L. olivacea on Playa La Flor from 1998 to 2006. Furthermore, in 2004 we established six plots (6 m × 6 m) on a 400-m section of the nesting...

Scientific Reports 6 : Article number: 27248 10.1038/srep27248 ; published online: 06 June 2016 ; updated: 21 September 2016 While this paper was under review, a correction was published to reference 17, which indicated that the reported dosage rate was incorrect.

Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationshi...

Summary information and references for all of the climate change models used in this study. (PDF)

Observed and future projections for SST in August at the five high use regions. A) August SST at the 5 high use areas for loggerheads in the Mediterranean. Solid lines are the linear trend lines (Adriatic R2 = 0.046; Aegean R2 = 0.555; Crete R2 = 0.499; Gabès R2 = 0.190; Zak/Kyp R2 = 0.251). B) Means of the projected changes in August SST from 13 c...

Surface and nest depth sand temperatures during the 2012 nesting season for three beach sectors of Rethymno, Crete. (TIFF)

Observed SST (1982–2012) during the mating season for Crete and Zakynthos/Kyparissia. (TIFF)

Relationship between mating period SST and day of first female emergence at Zakynthos (p < 0.001, R2 = 0.830, y = -12.157(x) + 378.97). (TIFF)

Relationship between mating period Ta and day of first female emergence at Zakynthos (p < 0.01, df = 25, R2 = 0.705; y = -6.8327(x) + 286.35). (TIFF)

Observed Ta (1982–2012) during the mating season for Kyparissia, Rethymno and Zakynthos. (TIFF)

The giant panda is an icon of conservation and survived a large-scale bamboo die off in the 1980s in China. Captive breeding programs have produced a large population in zoos and efforts continue to reintroduce those animals into the wild. However, we lack sufficient knowledge of their physiological ecology to determine requirements for survival no...

Anthropogenic stressors such as habitat loss are a global problem for wildlife. Coastal development in the United States has replaced estuary shorelines with hard erosion barriers. In Barnegat Bay, New Jersey, the diamondback terrapin (Malaclemys terrapin) encounters these barriers when approaching upland beaches for nesting. To determine the effec...

While telemetry is an invaluable tool for tracking animal movement patterns, the data generated by this technique is often challenging to interpret. Here, we addressed this issue by developing a novel method, based on changepoint analysis, which incorporated both the horizontal and vertical movement metrics and compared this output to that from a s...

The most recent climate change projections show a global increase in temperatures along with precipitation changes throughout the 21(st) century. However, regional projections do not always match global projections and species with global distributions may exhibit varying regional susceptibility to climate change. Here we show the effect of local c...

Increasing sand temperatures resulting from climate change may negatively impact sea turtle nests by altering sex ratios and decreasing reproductive output. We analyzed the effect of nest shading and watering on sand temperatures as climate mitigation strategies in a beach hatchery at Playa Grande, Costa Rica. We set up plots and placed thermocoupl...

Human development can impede wildlife moving between complementary habitats, particularly in highly disturbed coastal ecosystems. Coastal barriers may affect the behavior of diamondback terrapins (Malaclemys terrapin), a salt-tolerant estuarine turtle that requires access to complementary upland habitat for annual nesting. We used telemetry to quan...

Desert resource environments (e.g., microclimates, food) are tied to limited, highly localized rainfall regimes which generate microgeographic variation in the life histories of inhabitants. Typically, enhanced growth rates, reproduction and survivorship are observed in response to increased resource availability in a variety of desert plants and s...

The decline in snake populations has been attributed primarily to anthropogenic disturbances, including habitat destruction and fragmentation. We radio-tracked Northern Pinesnakes (Pituophis m. melanoleucus) in a military Target Zone and in the surrounding undisturbed buffer zone at the Warren Grove Gunnery Range in the New Jersey Pine Barrens, USA...

Background/Question/Methods The highest rate of shoreline development of any mid-Atlantic estuary in the United States is in Barnegat Bay, New Jersey, where bulkheading has increased 30% over the past 30 years. Bulkheading could affect the behavior of diamondback terrapins (Malaclemys terrapin), a threatened, salt tolerant estuarine turtle that r...

East Pacific green turtles (Chelonia mydas), often referred to as black turtles, are smaller and exhibit a lower reproductive output than other populations of green turtles in the Atlantic, Indian and Western Pacific Oceans. Knowledge of nesting ecology of East Pacific green turtles is limited to general descriptions. We conducted an exhaustive ana...

ABSTRACT: Knowledge of the mechanisms influencing phenology can provide insights into the adaptability of species to climate change. Here, we investigated the factors influencing multidecadal trends in the nesting phenology of the leatherback turtle Dermochelys coriacea at Playa Grande, Costa Rica, in the eastern Pacific Ocean and at Sandy Point, U...

Fisheries bycatch is a critical source of mortality for rapidly declining populations of leatherback turtles, Dermochelys coriacea. We integrated use-intensity distributions for 135 satellite-tracked adult turtles with longline fishing effort to estimate predicted bycatch risk over space and time in the Pacific Ocean. Areas of predicted bycatch ris...

Using satellite transmitters, we determined the internesting movements, spatial ecology and diving behavior of East Pacific green turtles (Chelonia mydas) nesting on Nombre de Jesús and Zapotillal beaches along the Pacific coast of northwestern Costa Rica. Kernel density analysis indicated that turtles spent most of their time in a particularly sma...

Habitat degradation and species introductions are two of the leading causes of species declines on a global scale. Invasive species negatively impact native species through predation and competition for limited resources. The impacts of invasive species may be increased in habitats where habitat degradation is higher due to reductions of prey abund...

Plant species documented during the 2010 resource availability surveys. Plant species found only at FM and SLNC are on the left and right, respectively, while species found at both wetlands are in the center. We documented 31 species at FM and 51 species at SLNC. (DOCX)

Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean, where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the...

Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Critically endangered leatherback turtles in the eastern Pacific Ocean are excellent candidates for such an assessment because their sensitivity to contemporary climate variability has been substan...

Satellite telemetry has helped reveal migratory movements of sea turtles. We attached satellite transmitters (MK10 Pat Tags) to 10 post-nesting East Pacific green turtles Chelonia mydas from Nombre de Jesús, Costa Rica (in 2006, 2007 and 2009) to track their movements, identify their foraging grounds, and elucidate their foraging behavior. Location...

Egg-burying reptiles need relatively stable temperature and humidity in the substrate surrounding their eggs for successful development and hatchling emergence. Here we show that egg and hatchling mortality of leatherback turtles (Dermochelys coriacea) in northwest Costa Rica were affected by climatic variability (precipitation and air temperature)...

Foraging success for pelagic vertebrates may be revealed by horizontal and vertical movement patterns. We show markedly different patterns for leatherback turtles in the North Atlantic versus Eastern Pacific, which feed on gelatinous zooplankton that are only occasionally found in high densities. In the Atlantic, travel speed was characterized by t...

Surface Currents and Vertical Thermal Structure in the Eastern Tropical and South Pacific Schematic representation of near-surface currents and vertical thermal structure in the eastern tropical and South Pacific, based on climatological annual data. (A) Current vectors (black) overlaid on current magnitude (colors; in cm s−1). Dashed black line de...

Current-corrected leatherback turtle swimming velocities. Frequency distribution of current-corrected leatherback turtle swimming velocities for a) North Atlantic (NA) leatherbacks, and b) Eastern Pacific (EP) tracks. (EPS)

Reproductive output is one of the most relevant aspects of life history. We analyzed the reproductive output of the endangered East Pacific green turtle (Chelonia mydas) nesting in Nombre de Jesús, Costa Rica. We supplemented beach patrols with ultrasonography to estimate clutch frequency. With ultrasound scans, we classified the stage of turtle ov...

Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean, where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the...

Interactions with fisheries are believed to be a major cause of mortality for adult leatherback turtles (Dermochelys coriacea), which is of particular concern in the Pacific Ocean,where they have been rapidly declining. In order to identify where these interactions are occurring and how they may be reduced, it is essential first to understand the move...

We compared small mammal community composition among undisturbed habitats and habitats disturbed by military operations on Warren Grove Gunnery Range (WGR) in the New Jersey Pinelands. WGR is one of the largest tracts of protected land within this globally rare ecosystem. Disturbance in the form of fire, mowing, soil disruption and logging has had...

So little is known about the early life history of leatherback turtles (Dermochelys coriacea) from hatchling to adulthood that this period has been termed the 'lost years'. For critically endangered eastern Pacific leatherback populations, continued and rapid declines underscore the urgent need to develop conservation strategies across all life sta...

Microbial relative abundance, diversity and richness were assessed based on 16S rRNA gene-based TRF community analysis via terminal restriction fragment (TRF) analysis on two olive ridley turtle arribada nesting beaches in Central America, Playa La Flor in Nicaragua and Playa Nancite in Costa Rica. Arribada beaches have very high densities of egg c...

The leatherback turtle is an endangered sea turtle whose numbers are in decline. There is a great effort world wide on the part of many conservationists to protect these turtles and their eggs. We previously demonstrated that blood from a leatherback hatchling was infected with a hemolytic acinetobacter bacterium, Acinetobacter sp. HM 746599, imply...

A newly described bacterial isolate, Acinetobacter sp. HM746599, has been obtained from leatherback sea turtle hatchling blood. The implication is that the hatchling was infected during development in the egg, which is substantiated by other studies to be reported by us in the future. The 16S rRNA gene sequence of the bacterium (GenBank accession n...

Leatherback turtles have an average global hatching success rate of ~50%, lower than other marine turtle species. Embryonic death has been linked to environmental factors such as precipitation and temperature, although, there is still a lot of variability that remains to be explained. We examined how nesting season, the time of nesting each season,...