Relating annual increments of the endangered Blanding's turtle plastron growth to climate

This research is the first published study to report a relationship between climate variables and plastron growth increments of turtles, in this case the endangered Nova Scotia Blanding's turtle (Emydoidea blandingii). We used techniques and software common to the discipline of dendrochronology to successfully cross-date our growth increment data series, to detrend and average our series of 80 immature Blanding's turtles into one common chronology, and to seek correlations between the chronology and environmental temperature and precipitation variables. Our cross-dated chronology had a series intercorrelation of 0.441 (above 99% confidence interval), an average mean sensitivity of 0.293, and an average unfiltered autocorrelation of 0.377. Our master chronology represented increments from 1975 to 2007 (33 years), with index values ranging from a low of 0.688 in 2006 to a high of 1.303 in 1977. Univariate climate response function analysis on mean monthly air temperature and precipitation values revealed a positive correlation with the previous year's May temperature and current year's August temperature; a negative correlation with the previous year's October temperature; and no significant correlation with precipitation. These techniques for determining growth increment response to environmental variables should be applicable to other turtle species and merit further exploration.

Habitat, movements, and behaviour of overwintering Blanding’s turtles (Emydoidea blandingii) in Nova Scotia

The overwintering ecology of a disjunct population complex of Blanding’s turtles ( Emydoidea blandingii (Holbrook, 1838)) in southwestern Nova Scotia was studied from January 2005 to April 2006. Sites were visited biweekly. We recorded structural characteristics and dissolved oxygen (DO), pH, and water and substrate temperatures in 7 overwintering sites containing at least 46 turtles and 7 paired “control sites”. Twenty-five adult turtles were radio-tracked to record locations and movements. Median winter temperature ranged from 0.8 to 8.6 °C in the organic substrate and from 0.3 to 7.6 °C in the water column. In overwintering sites, median DO ranged from 2.8 to 11.3 mg/L and median pH ranged from 4.6 to 5.5. Blanding’s turtles can tolerate submergence under ice for at least 3 months in severely hypoxic conditions. Movement was positively correlated with water temperature. Although some moderate movements were made during winter, 90% were less than 5 m. Movement to overwintering sites (September to mid-November) was gradual, but departure (late March to April) was rapid. Physical characteristics and environmental variables varied dramatically among overwintering sites, and no consistent patterns were observed between overwintering and control sites. We suggest that Blanding’s turtles return to communal sites year after year because of site fidelity and mating opportunities.

Reversal of lidocaine with epinephrine epidural anesthesia using epidural saline washout

BACKGROUND AND OBJECTIVES

Prolonged motor and sensory block following epidural anesthesia can be associated with extended postoperative care unit stays and patient dissatisfaction. Previous studies have demonstrated a more rapid motor recovery following the administration of epidural crystalloids in patients who had received plain bupivacaine and lidocaine epidural anesthesia. However, epinephrine is commonly added to local anesthetics to improve the quality and prolong the duration of the epidural block. The objective of this study was to determine the relationship of 0.9% NaCl epidural catheter flush volume (i.e., washout) to the recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia.

METHODS

A prospective, randomized, double-blind study design was utilized. Thirty-three subjects scheduled for elective gynecologic or obstetrical surgical procedures underwent epidural anesthesia using 2% lidocaine with epinephrine (1:200,000). A T4 dermatome level of analgesia, determined by toothpick prick, was maintained intraoperatively. Following surgery, subjects were randomized to 1 of 3 treatment groups. Group 1 (control, n = 11) received no epidural 0.9% NaCl (normal saline [NS]) postoperatively. Group 2 (15 mL NS x 1, n = 10) received an epidural bolus of 15 mL NS. Group 3 (15 mL NS x 2, n = 12) received an epidural bolus of 15 mL NS postoperatively and a second 15-mL NS bolus 15 minutes later. Assessment of motor and sensory block was performed at 15-minute intervals until complete motor and sensory recovery.

RESULTS

Times to partial and full motor and sensory recovery were significantly faster in the epidural NS groups than in the control group. Full motor recovery was more rapid in subjects receiving two 15-mL NS epidural NS boluses (30 mL total) compared with those receiving a single 15-mL NS bolus (108 +/- 9 min v 136 +/- 13 min) and significantly faster than control group subjects (153 +/- 14 min). Both NS x 1 and NS x 2 epidural bolus groups experienced significantly reduced times to complete sensory recovery when compared with the control group (NS x 1 = 154 +/- 13 min, NS x 2 = 153 +/- 9 min, control 195 +/- 14 min).

CONCLUSIONS

A more rapid recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia can be achieved with the use of 30 mL NS epidural washout. Reg Anesth Pain Med 2001;26:246-251.

Nesting ecology of Blanding's turtle (Emydoidea blandingii) in Nova Scotia, the northeastern limit of the species' range

This study was conducted to obtain accurate information on the reproductive ecology of the threatened population of Blanding's turtle (Emydoidea blandingii) in Nova Scotia. In 1994, 1995, and 1996, beaches and roadways in Kejimkujik National Park were surveyed for nesting turtles; all nests observed were covered with wire-screen cages to prevent predation and facilitate the collection of data on incubation and nest success. Nesting lasted from mid-June until early July. In each year, 80% of nesting occurred during a 10-day period in the third and fourth weeks of June. Turtles nested in the evening and predominantly on lakeshore cobble beaches. Site fidelity is high in this population: 73.3% of multiparous females returned to nest on the same beach in all years. No female produced more than one clutch per season, and most females (67.9%) nested less than annually. Mean clutch size was 10.6 eggs. Hatchlings emerge in September and October. Incubation times ranged from 80 to 128 days (mean = 94 days, SD = 11.7 days; n = 26 nests). In 1994 and 1995, most protected nests were productive; that is, 76.4 and 93.3% of protected nests produced at least one live hatchling in 1994 and 1995, respectively. In 1996, only 18.1% of protected nests were productive. Between 50 and 75% of productive clutches contained unhatched eggs and, on average, between 1.0 and 1.2 eggs failed per productive clutch. Total annual egg failure ranged from 26.5 to 94%. In the absence of nest predation, lower temperatures during incubation and nest flooding appear to be major cause of egg failure in this population. More effective means of reducing nest failure and bolstering recruitment must be implemented if efforts to aid the recovery of this threatened population of Blanding's turtle are to be successful.

A preliminary examination of genetic variation in a peripheral population of Blanding's turtle, Emydoidea blandingii

Random amplified polymorphic DNA (RAPD) was used to compare the Nova Scotia population of Blanding's turtle (Emydoidea blandingii) with several populations from the species' main range. The Nova Scotia population is believed to have been isolated from the main range for 4000-8000 years. Cluster analysis using a neighbour-joining algorithm produced a dendrogram showing the Nova Scotia population clustering separately from those populations in the main range. Analysis of molecular variance shows 34.28% of total variance to be accounted for between the Nova Scotia population and populations in the main range. While this study is preliminary, the results suggest that the Nova Scotia population of Blanding's turtle may be important to the maintenance of genetic diversity in the species.

Postemergence behaviour of neonates in a northern peripheral population of Blanding's turtle,Emydoidea blandingii, in Nova Scotia

The early postemergence behaviour of neonate Blanding's turtles, Emydoidea blandingii, was studied in Nova Scotia in 1994 and 1995 to test the hypothesis that hatchlings go to water immediately upon emergence from the nest. At the northeastern limit of the species' range, hatchling turtles should seek aquatic hibernacula to avoid freezing; where emergence from the nest is delayed until late autumn, selection pressure for water-seeking behaviour should be strong. Using pigmented powder that fluoresces under UV light, 78 hatchlings from 12 lakeshore nests and 2 inland nests were tracked for a maximum of 11 days. On the first day after emergence, hatchling movement was random with respect to water. Hatchlings did not orient themselves with respect to slope, vegetation, or nestmates, nor did individuals follow a consistent compass bearing among days. Often trails were convoluted in the open and relatively straight under dense vegetation. Evidence suggests that hatchlings in this population may overwinter in terrestrial as well as aquatic hibernacula.

A comparison of the male genitalia of three Calopteryx species (Odonata: Calopterygidae)

We compared the morphology of male genitalia in the damselflies Calopteryx maculata (P. de Beauvois), C. aequabilis Say, and C. amata Hagen in Nova Scotia. Differences were most pronounced between C. maculata and the other two species. The number of spines and the arrangement and density of spinulae on the ventrolateral surface of the penis shaft varied among species; the largest species, C. amata, had three times as many spines as did the smallest, C. maculata. Scanning electron micrographs of penes revealed structures in C. aequabilis and C. amata similar to those in C. maculata. Males of both C. amata and C. aequabilis can likely remove sperm from the reproductive storage organs of females, as previously shown in C. maculata and C. dimidiata.

The influence of oviposition resources on the dispersion and behaviour of calopterygid damselflies

We manipulated the size of oviposition patches to test two hypotheses: (i) in Calopteryx species males position themselves at patches where they have the greatest probability of finding females, and (ii) females are more strongly attracted to patches with the most oviposition resources. More females were attracted to large patches in all three species studied. In Calopteryx amata and Calopteryx maculata single males maintained territories at small patches and several males concurrently occupied and patrolled large patches. Calopteryx maculata males divided the large patches into small, individual territories, whereas C. amata males at large patches were unable to maintain exclusive areas. There were single territorial Calopteryx aequabilis males at both large and small patches. Time budgets of individual males were affected by the size of the oviposition patch most strongly in C. amata, where at large patches males engaged in aggression, patrolling, and courtship more frequently and for longer than at small patches. Calopteryx maculata males courted more frequently at large patches, but patrolling and male–male aggression were unaffected. Time budgets of C. aequabilis were virtually unaffected by the size of the oviposition patch. The frequency of mating by individual males did not differ between patch sizes for any of the three species. Dispersion and behaviour of damselflies of Calopteryx species are modified by the size and availability of oviposition resources.

Life history characteristics and movements of the woodland jumping mouse, Napaeozapus insignis, in Nova Scotia

We examined abundance, reproduction, movements, and adult–juvenile interactions of Napaeozapus insignis in a 5-year mark–recapture study in Nova Scotia. Densities of N. insignis varied greatly between years, mainly as a result of variation in overwintering survival of juveniles and breeding success of females. Year-to-year survival rates of adults were relatively constant (approximately 26%), whereas those of juveniles fluctuated widely. Adult females produced only one litter per season, and no juvenile reproduced in the summer of her birth. Length of the active season was 12–17 weeks, and timing of emergence from hibernation varied little from year to year. Males emerged from hibernation 15–33 days earlier than females, and their captures were clustered along portions of the transects adjacent to steep slopes, which may have provided well-drained hibernation sites. The overall sex ratio did not differ from 1:1, but in May it was biased towards males, and in July and August adult females outnumbered adult males. Distances moved by adult males and females within 24 h were similar (mean for males = 97 m, for females = 61 m), but home ranges of males between June and August were greater than those of females (mean distance between two farthest captures for males = 447 m, for females = 175 m). Results from a removal experiment, as well as examination of trapping records, indicated that adult females inhibited early capture of juveniles when densities of adults were high. We suggest that the suite of life history traits (long life-span, late maturity, infrequent reproduction) that northern zapodids exhibit relative to southern zapodids is best explained by a bet-hedging hypothesis. Long winters and short summers in the north contribute to low and unpredictable overwintering survival of juveniles. By directing energy from reproduction into accumulation of hibernation fat, adults increase their chances of surviving to breed again the next summer and thus decrease the probability of leaving no young at all.

An unusual decline in abundance of Peromyscus maniculatus in Nova Scotia

Capture success for deer mice (Peromyscus maniculatus) in 18 499 trap nights (TN) at 16 localities in northern Nova Scotia between 1977 and 1982 indicates an unusual and prolonged decline in abundance of that species in habitats it normally occupies. The decline has been most extreme on hardwood slopes in the Cape Breton Highlands. The population on Isle Haute, an isolated island in the upper Bay of Fundy, has shown no decline during the sampling period.

Radio tracking of small mammals using a grid of overhead wire antennas

A radiotelemetry system is described that can be used to monitor three activity states of, and distance travelled by, mammals as small as Clethrionomys gapperi, having a winter weight of 16 g. Precision with which animals are located is constant and error does not exceed 75 cm. Preliminary biological results show marked seasonal changes in activity patterns. Advantages and disadvantages of the grid of fixed antennas vis à vis triangulation systems are discussed and other potential uses of the system are suggested.