Linking movement and reproductive history of brook trout to assess habitat connectivity in a heterogeneous stream network

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Using stable isotope analysis with telemetry or mark-recapture data to identify fish movement and foraging

Information about animal movements has often been inferred from stable isotope analysis (SIA), but is dependent on animals assimilating site-specific isotopic signatures via diet. This potential weakness in ecological interpretation can be overcome by using other investigative tools that provide precise information about individual movement patterns. In this paper, we demonstrate the value of combining SIA with telemetry or mark-recapture data from trapping, electrofishing and remote detection of individuals to study the movement and feeding ecology of fishes in different habitats. In a fjord lake system in Newfoundland, Canada, juvenile Atlantic salmon delayed downstream migration (smolts) or actively moved into a large lake (parr) where they foraged for periods reflecting different life history strategies. In the Miramichi River (New Brunswick, Canada), SIA provided evidence of distinct foraging habitats (tributary versus large river). By tracking fish implanted with passive integrated transponder (PIT) tags, we distinguished between movements related to foraging versus seeking cool water refugia during high temperature events. Finally, site fidelity and limited mobility of slimy sculpin, a small benthic fish, was established where δ¹³C in muscle tissue showed a progressive enrichment downstream and where a median displacement of <10 m was estimated for sculpin tagged with PIT tags. Technological improvements have permitted non-destructive tissue sampling of wild fishes for SIA, and the tagging and remote detection of animals smaller than was previously possible. These advancements and the combination of investigative tools promise new insights into animal ecology.     

Genetic Variation among <Emphasis Type="Italic">Ambystoma</Emphasis> Breeding Populations on the Savannah River Site

We surveyed 16 Carolina bay breeding ponds for Ambystoma salamanders. Tail tissue samples were collected from adult and juvenile mole salamanders (A. talpoideum), marbled salamanders (A. opacum), and spotted salamanders (A. maculatum) captured leaving the Carolina bays. We used amplified fragment length polymorphisms (AFLP) to determine the genetic variation associated with the breeding populations. The Carolina bays could be considered as individual populations, metapopulation groups, or as one big metapopulation depending on gene flow between these bays. Bays range from less than 100 m apart to more than 24 km apart, much further than any reported movement for these species. Animals were marked in the field. We documented little movement of salamanders between breeding locations. Using 392 polymorphic bands produced with the AFLP technique, we were able to separate the samples into the correct species from which the tissues were collected. However, within species analyses failed to find structure associated with populations of salamanders. We failed to document a correlation between geographic and genetic distance (Mantel r = 0.05235, P=0.6800 for mole salamanders; r = 0.46077, P=0.9547 for marbled salamanders). Only 27.8% of mole salamanders and 60.9% of marbled salamanders were assigned back to the population of capture. The majority of the genetic variation was attributable to the individual as opposed to the population. The results of this study suggest that while the majority of these salamanders may be philopatric, some mixing maybe occurring or alternatively, that these populations have not been genetically isolated for sufficient time to develop unique genotypes through drift.     

Concentrations of lactic acid in neotenic and transformed tiger salamanders (Ambystoma tigrinum) before and after activity

Summary Concentrations of lactic acid in bodies of inactive neotenic tiger salamanders were similar to those recorded for inactive transformed animals. Transformed salamanders swimming against a water current for 5 min accumulated significantly more lactate in their body fluids than did neotenic salamanders, but subsequently metabolized the lactate at higher rates than characterized neotenic animals. Total body lactate in both morphs decreased rapidly in the first 1–1/2 h after activity, and within 6 h had returned to the level (common to both morphs) observed prior to activity. Whereas neotenic animals apparently swim with greater efficiency than transformed salamanders (4.26 mole ATP/gvs. 6.06 mole ATP/g expended by neotenic and transformed animals, respectively, during 5 min of continuous swimming), the transformed animals exhibit a metabolic adaptation to aquatic existence enabling them rapidly to recover from a lactacid debt.     

High detectability with low impact: Optimizing large PIT tracking systems for cave‐dwelling bats

Passive integrated transponder (PIT) tag technology permits the “resighting” of animals tagged for ecological research without the need for physical re‐trapping. Whilst this is effective if animals pass within centimeters of tag readers, short‐distance detection capabilities have prevented the use of this technology with many species. To address this problem, we optimized a large (15 m long) flexible antenna system to provide a c. 8 m² vertical detection plane for detecting animals in flight. We installed antennas at two roosting caves, including the primary maternity cave, of the critically endangered southern bent‐winged bat (Miniopterus orianae bassanii) in south‐eastern Australia. Testing of these systems indicated PIT‐tags could be detected up to 105 cm either side of the antenna plane. Over the course of a three‐year study, we subcutaneously PIT‐tagged 2,966 bats and logged over 1.4 million unique detections, with 97% of tagged bats detected at least once. The probability of encountering a tagged bat decreased with increasing environmental “noise” (unwanted signal) perceived by the system. During the study, we mitigated initial high noise levels by earthing both systems, which contributed to an increase in daily detection probability (based on the proportion of individuals known to be alive that were detected each day) from <0.2 (noise level ≥30%) to 0.7–0.8 (noise level 5%–15%). Conditional on a low (5%) noise level, model‐based estimates of daily encounter probability were highest (>0.8) during peak breeding season when both female and male southern bent‐winged bats congregate at the maternity cave. In this paper, we detail the methods employed and make methodological recommendations for future wildlife research using large antennas, including earthing systems as standard protocol and quantifying noise metrics as a covariate influencing the probability of detection in subsequent analyses. Our results demonstrate that large PIT antennas can be used successfully to detect small volant species, extending the scope of PIT technology and enabling a much broader range of wildlife species to be studied using this approach.     

The periphyton index of trophic status PIT: a new eutrophication metric based on non-diatomaceous benthic algae in Nordic rivers

Eutrophication is one of the major problems for surface water quality in Norway, particularly in the lowlands near settlements and agricultural areas. Here, we present a new index based on non-diatomaceous benthic algae (Periphyton index of trophic status, PIT) which is developed on a dataset of >500 samples from >350 sites from the Norwegian mainland and can be used to describe trophic status at a river site. PIT indicator values for benthic algae taxa are derived from water total phosphorus concentrations and range from 1.87 for Stigonema hormoides to 68.91 for Tribonema sp. PIT site values range from 3.42 to 44.45 and cover a range from oligotrophic to eutrophic conditions. The relationship between the PIT and the total phosphorus concentration has one major threshold at 10 μg/l TP, with a slow increase below and a steep increase above 10 μg/l. We conclude that benthic algae species composition at nutrient poor sites reacts only slightly to small increases in phosphorus concentration, while it is most sensible to eutrophication in the range between 10 and 30 μg TP/l. For the genus Oedogonium, we found a significant positive correlation between filament width and TP concentration, making Oedogonium an easy to use eutrophication indicator.     

Movements and diving of bearded seal (Erignathus barbatus) mothers and pups during lactation and post-weaning

Eleven bearded seals (Erignathus barbatus) were tagged with satellite-linked dive recorders in Kongsfjorden, Svalbard, Norway, in May 1994. These animals included four mother-pup pairs and three single pups. The seals were tracked for 21–258 days. A total of ˜207,000 dives were recorded. Bearded seal mothers showed limited movements during the nursing and moulting periods. After weaning, the pups moved out of the tagging area and dispersed coastally. One pup left Svalbard and moved far offshore to Greenland and Jan Mayen. Bearded seal adults displayed a bi-modal dive behaviour, with peaks of activity that were shallower than 10 m or from 50 to 70 m. Most dives for adult seals (97%) were shorter than 10 min. Young pups performed dives that were shallower and shorter in duration than their accompanying mothers, but diving skills improved rapidly with age. Six of the seven pups dived deeper than 448 m by the time they were 2 months old. Analyses of movement data with respect to separation of mother-pup pairs suggest a lactation period of about 24 days. Accepted: 31 January 2000     

Activation of Neurons of the Medullary Centers of the Autonomic Nervous System Related to Motivated Operant Movements Realized by Rats

Using the corresponding techniques, we visualized Fos-immunoreactive (Fos-ir) and NADPH diaphorasereactive (NADPH-dr) neurons in the medullary centers of the autonomic nervous system (ANS) of rats, which performed repetitive operant movements (catching of food globules from the manger by the left forelimb under conditions of high food motivation). Animals were trained to perform operant movements in 30 min-long everyday sessions during 12 days. The duration of a single food-procuring movement was about 600 msec. Realization of the operant reflex was accompanied by clearly expressed motivational/affective reactions. The heart rate (HR) in the course of each operant movement sharply dropped (on the 10th day of training, by 12%, on average) with subsequent recovery of this parameter within 3–4 sec. In the course of 30-min-long training sessions, the mean HR gradually decreased (in the examined group, 7%, on average) within an interval from the 5th to the 20th min with subsequent recovery until the end of the training session. The mean numbers of Fos-ir neurons in the medullary nuclei of the ANS (Sol, IRt, CVL, RVL, Amb, 10, and MdD) of rats performing food-procuring movements (n = 4) were significantly (P < 0.05) greater than those in the control, and the intensities of c-fos expression in these structures corresponded to the following succession: Sol > IRt > CVL+RVL/CVL > RVL. Large Fos-ir neurons were observed in the dorsal motor nucleus of the n. vagus (10) and in the Amb/RAmb nuclei. In a considerable proportion of neurons of the Sol and single cells of the 10 and Amb, we observed double labeling (Fos-ir + NADPH-dr). Thus, operant food-procuring movements are accompanied by episodes of bradycardia related to each separate realization; in addition, a long-lasting tonic decrease in the HR developed. These autonomic reactions are mediated by the abovementioned medullary ANS nuclei. It is supposed that the respective weakening of inhibitory sympathetic effects on spindle receptors of the muscles involved in realization of the above operant movements can provide facilitation of generation of proprioceptive impulsation, facilitation of monosynaptic spinal reflexes, and, finally, an increase in the efficacy of targeted limb movements directed toward food procurement.     

Riparian disturbance restricts in‐stream movement of salamanders

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Ranging behaviour of a large freshwater invertebrate, the white-clawed crayfish Austropotamobius pallipes

• 1 Radio‐telemetry and mark‐recapture methods were used to study the summer movements of adult and juvenile white‐clawed crayfish, Austropotamobius pallipes from a wild population in a small braided stream, Dalton Beck, North Yorkshire, U.K. Radio‐transmitters were attached to the chelae of 18 large (> 35 mm carapace length) crayfish and individuals were subsequently located to within 0.15 m. Additionally a total of 888 crayfish were marked with carapace brands, and 83 were recaptured.
• 2 Radio‐tracked crayfish exhibited significantly greater local activity at dusk (21.00–00.00) than at dawn (03.00–06.00), or during morning (09.00–12.00) and afternoon (15.00–18.00) monitoring periods.
• 3 The greatest movements of radio‐tracked crayfish occurred within 2 days of release. After this time, periods of residence were interspersed by movements to new locations, interpreted as establishment of ephemeral home areas. It is suggested that the initial large movements were the result of a ‘fright response’ following capture.
• 4 Movements varied widely between individuals, some moving more than 300 m in 10 days, while others showed little movement over an equivalent time period. Mean (±SE) daily movements were 4.6 ± 3.0 m for males and 1.5 ± 1.0 m for females. Although crayfish often used specific home sites for in excess of 7 days, displaced animals did not return to home sites.
• 5 The total distances travelled and the mean distance travelled per day by individual radio‐tagged crayfish did not differ significantly between upstream or downstream directions or between males and females. This was also the case for marked crayfish used in mark‐recapture studies.
• 6 Positive correlations between distance moved per day and size (carapace length) were found for downstream movements by male and female crayfish, but not for upstream movements.
• 7 Some preliminary observations of the response of crayfish to flood events suggested that these could be catastrophic with two out of five tracked crayfish found dead after a high stream‐discharge event.

     

Salamander Dispersal Across a Forested Landscape Fragmented by a Golf Course

Abstract: We assessed dispersal behavior of 78 radiotagged adult spotted salamanders (Ambystoma maculatum) at a 36-hole golf course in southeastern Connecticut, USA. Lake of Isles Golf Course is atypical of most golf courses in North America because it is much larger (461 ha) than average 18-hole golf courses (54 ha) and deciduous forests accounted for 70% landscape composition on the course. We tracked individuals an average of 164 days as they emigrated from 3 seasonal pools surrounded by golf course fairways and one pool located in contiguous forest (control pool) from March through December 2004. Males and females dispersed similar distances at the control pool, averaging 71 ± 10 m. However, females migrating across the golf course dispersed twice as far (214 ± 25 m) as males on the golf course (102 ± 15 m) and both genders at the control pool. Over 40% the salamanders at the golf course crossed fairways; thus, fairways were not a dispersal barrier to adult spotted salamanders. Previous researchers have suggested establishing a 164-m life zone around breeding ponds to protect pond-breeding amphibian populations. Our results suggest that strategies that protect core upland habitat within 164 m of wetland boundaries would include 82% of adult males and only 50% of adult females. Empirical estimates based on our telemetry study suggest that core terrestrial habitat would have to extend 370 m to protect 95% of adult females, which is much farther than previous estimates.     

Movements of brown smoothhounds, <Emphasis Type="Italic">Mustelus henlei</Emphasis>, in Tomales Bay,California

Ultrasonic telemetry was used to analyze the effects of environmental variables on movement directions and movement rates of brown smoothhounds, Mustelus henlei, in Tomales Bay, California. Ultrasonic transmitters were surgically implanted in the peritoneal cavities of one male and five female brown smoothhounds and tracked during the period of 29 June to 15 July 2004. Coarse-scale tracking consisted of locating all tagged individuals multiple times during a single session, while fine-scale tracking consisted of following a single individual continuously during a session. Coarse-scale tracking suggested movement toward the inner bay with incoming and high tides and toward the outer bay with outgoing and low tides (P = 0.01), whereas the diel cycle had no apparent effect on their movement directions. Mean shark movement rate was 0.09 m s⁻¹ (range: 0.01–0.34 m s⁻¹), with diel and tidal cycles both having significant effects on their rates of movement (P = 0.02 and P < 0.01), respectively. We tracked two female sharks on a fine scale over three tracking sessions in July 2004. Both individuals exhibited higher rates of movement during the night compared to the day (P < 0.01). While one shark’s rate of movement was not significantly affected by tidal stage, the other’s was (P < 0.001).     

Movement of Sacramento Sucker, Catostomus occidentalis, and Hitch, Lavinia exilicauda, during a Spring Release of Water from Camanche Dam in the Mokelumne River, California

Synopsis We recorded the movement of Sacramento suckers, Catostomus occidentalis, and hitch, Lavinia exilicauda, before and during a controlled flood release on a regulated California Central Valley River, using radio telemetry. Both species made small, local movements (<550 m) during pre-flood flows. During flood releases, some individual suckers made significantly larger movements (>8100 m) both up and downstream of pre-flood flow locations within the main channel while others did not. In contrast, increased flows did not significantly influence hitch movement from a side-channel pool. Sacramento suckers tended to move upstream during flow increases and downstream during flow reductions while no strong relationship for hitch was apparent. These data show that native Central Valley fishes may exhibit a variety of responses to flow change, including schooling and spawning activity, movements to refugia from higher velocities and no marked change. Managers must take into account life history, age and timing associated with specific species when implementing controlled flow strategies.     

Productivity and significance of headwater streams: population structure and biomass of the black-bellied salamander (Desmognathus quadramaculatus)

1. Headwater streams are a significant feature of the southern Appalachian landscape, comprising more than 70% of the total stream length in the region. Salamanders are the dominant vertebrate within headwater‐riparian forest ecosystems, but their ecological role is not clearly understood. 2. We studied a population of black‐bellied salamanders (Desmognathus quadramaculatus) at a headwater stream in the southern Appalachian Mountains using radio‐telemetry and mark‐recapture methods. The length and area of headwater streams in the region were estimated using GIS. 3. Home ranges of radio‐tracked salamanders were relatively small (mean = 1.06 m²). Adult salamanders in our telemetry study inhabited edge microhabitats significantly more often than either stream or riparian microhabitats, and the same trend was observed in the mark‐recapture study. 4. We estimated the population density at this site to be 11 294 salamanders ha^?1, amounting to 99.30 kg ha^?1 of biomass, an estimate that is six times greater than reported in previous studies. The majority of this biomass was found within the stream, but 22% was found in the surrounding riparian habitat more than 1 m from the stream. Using headwater stream length and area estimates, we extrapolated biomass estimates for black‐bellied salamanders inhabiting stream and riparian microhabitats across the study region. 5. We report one of the largest estimates of secondary consumer biomass for a headwater ecosystem, attesting to the overall productivity of headwater streams. Headwaters are known to be important for ecological and ecosystem processes and our biomass estimates suggest that salamanders are a critical component to these systems.     

Movement behaviour of the small benthic Rhine sculpin <Emphasis Type="Italic">Cottus</Emphasis> <Emphasis Type="Italic">rhenanus</Emphasis> (Freyhof,Kottelat &; Nolte, 2005) as revealed by radio-telemetry and pit-tagging

From February 2006 to June 2007, we followed the movement patterns of the Rhine sculpin (Cottus rhenanus) by combining short-term radio-telemetry (n = 10 radio-tagged sculpin with a miniature 0.5-g transmitter) and long-term individual (PIT-tag) mark-recapture (n = 452 PIT-tagged sculpin during six removal electric fishing operations) studies in a small tributary of the River Meuse, Belgium. During a 25- to 27-day period, the radio-tracked sculpin displayed various mobility patterns, showing frequent movement from one day to another and longitudinal home ranges from 7 to 46 m, with cumulative distances up to 149 m. During the mark-recapture study, most (99%) recaptured PIT-tagged individuals moved from their original 5-m long site, subsequently using longitudinal home ranges between 5 and 435 m (mean, 50 m; median, 20 m). The most common movement behaviour was alternation between upstream and downstream movements (62%), followed by directional upstream (26%) and directional downstream (11%) movement. Using the latest available techniques, this study builds on the current knowledge on the Cottus genus and closes gaps in the comprehension of sculpin movement and home range at a scale that had not been investigated to date.     

Directional and Non-directional Movements of Bat Rays, <Emphasis Type="BoldItalic">Myliobatis californica,</Emphasis> in Tomales Bay,California

Synopsis The goal of this project was to determine if bat rays, Myliobatis californica, display oriented movements and are thus a viable model species for the further study of geomagnetic topotaxis in elasmobranches. We tracked one male and three female rays during September 1998 and August and September 2001 in Tomales Bay, California. The rays exhibited two modes of travel: (1) rapid and highly directional movements in a straight line along the length of the bay and (2) slow and non-directional movements within small areas. Directional movements were defined as point-to-point vectors in the paths of the bat rays that were oriented in similar directions, and the distribution of these was clustered rather than dispersed and uniform. Mean rates of movement during directional swimming approached 0.5 m s⁻¹. In contrast, vectors in the path of bat rays were at times oriented in varying directions, and a distribution of these was widely dispersed as we would expect if the rays were moving randomly. These were defined as non-directional movements. Oriented straight-line swimming is consistent with the species either being able to orient to the bathymetry of the bay or possessing a compass and (or) piloting sense.     

Dispersal movements of non-native and native terrestrial slugs in an urban environment

Animal movement varies from undirected dispersal to directed migration. Movement rates may have implications for conservation and resource management, as well as pest control, and they play a key role in invasion success. In slugs, long-distance dispersal is typically passive, whereas active movement is critical for local dispersal and determines access to resources such as food and shelter. Telemetry has recently been used to study individual slug movements in the wild, whereas movement in arena tests has explored mechanisms of interspecific competition and invasiveness in slugs. Studies that relate the performance of individual slugs in arena tests to their post-release behavior in nature are lacking. We measured individual short-term movement speed of commonly occurring native and non-native slugs of the genera Arion and Limax in arena tests and tracked their post-release dispersal movements in a garden by PIT telemetry. We demonstrate clear differences in movement behavior among the species, but non-native slugs did not display higher movement rates than their native congeners. In the arena test, slugs of the genus Limax displayed a higher short-term speed than slugs of the genus Arion, whereas in the field, individuals of Limax maximus showed lower dispersal rates compared to the other slug species. Moreover, there was a positive correlation between short-term speed in the arena test and movement in the field among individuals of L. cinereoniger, indicating the possible existence of behavioral syndromes in slugs, which may link movement ecology, animal personality, and the invasion ecology of pest species.     

Untersuchungen über den beschleunigenden Einfluß mechanischer Schwingungen auf die positive Phototaxis bei Locusta migratoria

Summary The speed of the phototactic movements of Locusta migratoria is increased when the animals are previously exposed to 3 min of vibrations. Although the speed of these movements is diminished when one or both antennae are removed, the relative increase in speed after vibration stimuli is maintained.     

Movement and habitat use by the marbled lungfish Protopterus aethiopicus Heckel 1851 in Lake Baringo, Kenya

The marbled lungfish, Protopterus aethiopicus, a recent introduction into Lake Baringo, Kenya is now an important commercial species there. Because little is known about its behaviour, we used ultrasonic telemetry to investigate its movements and use of habitat as part of a broader biological study. Twelve marbled lungfish were implanted with ultrasonic tags and tracked for variable periods between September 2001 and 2002. Two individuals were tracked for most of the study period. Daily movement ranged from little or none to 5.2 km. Mean hourly rates of movement for three fish located twice a day (morning and late afternoon) over several days suggested that individuals were active throughout the diel period. Maximum lake depth was about 3 m and fish utilized all depths greater than 1 m. Six home ranges described for four lungfish varied in size from 5.8 to 19.8 km ² and were occupied for between 2 and 4.5 months. Use of habitat and the movement of marbled lungfish in Lake Baringo appeared to be influenced more by biotic than abiotic factors.     

Age‐ and sex‐related differences in the spatial ecology of a dichromatic tropical python (Morelia viridis)

Abstract: Despite outnumbering their temperate counterparts, tropical snake species have been poorly studied. Yet, the few tropical species that have been studied show a variety of behavioural traits beyond those described in temperate species. Here we reveal both age and sexual differences in the movements of tropical green pythons (Morelia viridis: Pythonidae). We radio‐tracked 27 individuals (17 females and 10 males) for up to 18 months, locating individuals during both the day and night. The home range size for adult females (mean ± SE of 6.21 ± 1.85 ha) was correlated with snout–vent length. Neither adult males nor juveniles had a stable home range. Adult females had stable home ranges that overlapped considerably with those of other females and yellow individuals. Multiple radio‐tracked adult males passed through the territory of radio‐tracked adult females during the study. Females of all sizes were more likely to change position each day than males. There were no differences between the sexes or size categories in the distances moved in most months, although the variation in movement distances was higher in the dry season than during the wet season. In the wet season (January–March) movement distances increased and these were size‐ and sex‐related. This increased activity may be associated with mate searching. Males of M. viridis may maximize their rate of encountering mature females by roaming rather than maintaining a home range. Juvenile green pythons moved distances equal to adult snakes in most months despite their comparatively small size.