Telemetry Collars Research Articles

DIAGNOSIS AND TREATMENT OF PRESUMPTIVE POSTOBSTRUCTIVE PULMONARY EDEMA IN A FLORIDA PANTHER (PUMA CONCOLOR CORYI)

A free-ranging, adult male Florida panther (Puma concolor coryi) was immobilized and evaluated for hematuria following routine capture. Prior to anesthetic recovery, the panther was fitted with a telemetry collar. After an initially quiet recovery, the panther began thrashing in the transport cage, and was again immobilized. Pink foam was evident from the nostrils, and crackles were ausculted over the chest, indicating pulmonary edema. Postobstructive pulmonary edema was diagnosed based on history, clinical signs, radiographic evaluation, and blood gas analysis. The animal was treated intensively for several hours with diuretics, oxygen, and manual ventilation. The panther responded rapidly to therapy and was released back into the wild 48 hr after presentation. Postobstructive pulmonary edema, also called negative-pressure pulmonary edema, may be underrecognized in veterinary medicine. In this case, the telemetry collar, in conjunction with anesthetic recovery in a small transport crate, may have contributed to tracheal obstruction. Wildlife veterinarians and biologists should be aware of the risk of airway obstruction when placing tracking collars, and animals should be continuously monitored during anesthetic recovery to ensure the presence of a patent airway.

Siberian Ibex (Capra sibirica) Home Ranges in Ikh Nart Nature Reserve, Mongolia: Preliminary Findings

Siberian ibex ( Capra sibirica ) remain poorly understood, as little is known about their ecology. We began studying ibex in Ikh Nart Nature Reserve, Dornogobi Aimag, Mongolia to better understand the species’ ecological needs and threats. In this paper we report on home range and core range sizes. We captured 27 ibex and fit them with radio telemetry collars using drive nets for adults and juveniles ( n = 22) and hand captures for neonatal kids ( n = 5). We collected 1,029 locations from September 2003 to February 2007. Throughout the study, 9 ibex with 40+ fixes used mean, annual home range sizes of 3,115.5 ± 504.2 ha using the Minimum Convex Polygon method. Home ranges calculated using the fixed kernel method were smaller: 475.9 ± 14.7 ha for 50% kernel and 1,808.0 ± 88.1 ha for 95% kernel. Ibex from different demographic groups (males vs. females and juveniles vs. adults) used remarkably similar home and core ranges; we found no significant differences among any demographic groups. Although not quantified, ibex mostly restricted their activities to areas with steep cliffs and rocky outcrops and home ranges overlapped extensively.

Balancing Number of Locations with Number of Individuals in Telemetry Studies

The study of habitat selection usually compares assessments of habitat use to habitat availability. To investigate habitat selection of large mammals today, researchers must choose between a few very expensive Global Positioning System (GPS) telemetry collars that can provide many locations and several inexpensive very high frequency telemetry collars that will provide few numbers of locations (unless substantial resources are spent in the field). We investigated the effects of number of locations and sampled animals on the outcome of habitat-selection analyses. We evaluated whether tracking frequency and sample size of individuals influenced our ability to detect habitat selection. We used data obtained from adult female moose fitted with GPS collars to generate data sets simulating various sampling frequencies and sample sizes of individuals. Tracking schedules conformed to those commonly used in ungulate telemetry studies (1 location every 14, 7, or 3 d and 1 or 3 locations per d) as did animal sample sizes (between 8 and 20 individuals). We determined habitat use and availability at the landscape and home-range scales during summer–autumn and winter. Precision of habitat use and availability estimates did not improve markedly with increasing tracking frequency. Only results obtained with the least-intensive tracking schedule (1 location every 14 d) differed from those obtained with the other schedules and only in 25% of the cases. Above this threshold in tracking frequency, number of sampled animals was clearly more important than number of locations in detection of habitat selection. Our results indicated that habitat-selection analyses were more sensitive to inter- than intra-individual variability. Depending on study objectives, it may be more profitable to prioritize number of sampled individuals rather than number of locations per individual. We suggest methods allowing researchers to assess inter-individual variability while studying habitat selection.

A habitat suitability index model to assess moose habitat selection at multiple spatial scales

We developed a habitat suitability index (HSI) model for moose (Alces alces) in the boreal forest. The model used two components: a suitability index for food (SIfood) and another for the interspersion between cover and food (SIedge). We used forest maps as the input data source, and the value of each stand type in terms of cover and food was based on field surveys. To validate the model, the habitat preference of moose equipped with global positioning system telemetry collars was assessed at both landscape and home-range scales. We expected the habitat-preference index to correlate with suitability indices determined using the global model and each of its two components. Habitat suitability was assessed in evaluation plots of 500, 100, and 10 ha. Unexpectedly, the habitat-preference index correlated better with SIfood and SIedge than with the global model. The suitability indices also performed better when assessed in large plots. Selection of 500 ha plots related mostly to SIedge, but SIfood was more important when smaller evaluation plots were used, especially for males. Females preferred plots with intermediate SIfood values. At the fine scale, SIedge was not as attractive to moose as was previously observed, presumably because snow conditions prevailing in our study area were relatively moderate. We recommend utilizing the model with SIedge in large plots (ca. 500 ha) and SIfood in smaller plots. Our model could be adapted and applied to other areas by using empirical data to adjust the relative value of stand types in terms of cover and food.

Development of a prolonged estrus effect for use in Judas goats

The use of Judas goats (JGs; Capra hircus) to locate remnant animals is a powerful tool for enhancing feral goat eradication efforts, being especially important to island conservation programs. JGs are goats that are captured, fitted with radio telemetry collars and released. As goats are gregarious, JGs search out and associate with other goats. They can then be tracked down and any associated feral goats removed. JGs increase the efficiency of removing animals at low densities by reducing search time for hunters locating remnant herds. Prolonged duration or increased frequency of estrus in female JGs could potentially increase the efficiency of this method; does in estrus actively seek out and are searched for by bucks, and are more active than non-estrus does. Two experiments under controlled, farm conditions demonstrated that estrus can be prolonged by using Compudose-100 implants (one or two implants; single dose 21.1mg estradiol 17β) or a single Synovex-S implant (200mg progesterone and 20mg estradiol benzoate). Two Synovex-S implants failed to significantly prolong estrus. Single Compudose-100 implants provided the most dramatic effect, and when combined with 15mg PGF2∝ and sterilization by tubal occlusion provides an effective means of terminating pregnancy, inducing sterility and prolonging estrus 6–16-fold compared to sterile does and at least 82-fold compared to unaltered does, with a single intervention. Incorporating these methods into Judas goat programs will likely increase the efficiency and capability of feral goat control and island conservation.

Field Test of GonaCon™ Immunocontraceptive Vaccine in Free-Ranging Female White-Tailed Deer

Author(s): Gionfriddo, James P.; Eisemann, John D.; Sullivan, Kevin J.; Healey, Ronald S.; Miller, Lowell A. | Abstract: Locally overabundant deer herds, particularly those inhabiting fenced or other enclosed areas in urban or suburban settings, are presenting serious problems for wildlife managers, landowners, and the general public. Traditional methods of population control, such as regulated harvest by licensed hunters, often are impractical or illegal in such settings. The development of safe and effective wildlife contraceptives is needed to control locally overabundant populations in situations where traditional management tools cannot be employed. During July 2004, we initiated a field study of GonaCon™ Immunocontraceptive Vaccine, developed by research scientists at the National Wildlife Research Center in Fort Collins, Colorado. This vaccine had previously been tested successfully as a contraceptive in captive animals including white-tailed deer, feral and domestic swine, and wild horses. The two-year field study was prompted by the need to manage an enclosed, overabundant population of white-tailed deer that had caused considerable ecological damage to a 662-acre, federally-owned, forested site in Silver Spring, Maryland. The U.S. General Services Administration, which manages the property, conducted an environmental assessment, which concluded that sharpshooting followed by immunocontraception would be the most appropriate deer management strategy. After 214 deer were removed from the site by sharpshooters, we set up and tested an automated radio telemetry system for tracking deer and monitoring their mortality. Twenty-eight does were then captured, equipped with ear tags and radio telemetry collars, and injected with GonaCon™ vaccine. Fifteen additional does were captured, marked, and released without vaccination as untreated control animals. Reproductive behavior and fawn production by the vaccinated and unvaccinated does will be monitored and compared for two years, and will be used to determine the efficacy of GonaCon™ as a wildlife contraceptive agent. Data from this study will be used to support EPA registration of GonaCon™ as a wildlife contraceptive agent.

Space use of moose in relation to food availability

We assessed the influence of temporal and spatial changes in food availability on home-range size and movements of moose (Alces alces (L., 1758)). Ten adult moose were radio-collared and monitored with GPS telemetry collars during two contrasting time periods based on food quality and availability: summer (growing period) and winter (dormant and snowy period). According to the habitat productivity – home-range size hypothesis, we expected home-range size and movement rate to be negatively correlated with the proportion of food-rich habitat types in home ranges. Food availability influenced space use, but the effect was more pronounced at the small scale (i.e., movement rates) than at the large scale (i.e., home-range sizes) and during winter than summer. The negative relationship between food availability and home-range size only existed in winter, but movement rates were lower in food-rich habitat types in both time periods. Our results suggested that body size was not the primary factor governing sex-related differences in space use which were likely more related to specific needs of females with regard to the feeding and protection of calves. We suggest that the habitat productivity – home-range size hypothesis may not always be supported when forage is widely distributed and that movement rates can be a better index of forage availability than home-range sizes in such situations.

Influence of topography and GPS fix interval on GPS collar performance

Topography, vegetation, and animal behavior may influence the performance of Global Positioning System (GPS) telemetry collars, affecting fix success rates and location error. We reviewed the scientific literature published from 1995 to June 2004 to determine the fix intervals used and fix success rates obtained in studies using GPS telemetry. We also programmed GPS telemetry collars with 6 different fix intervals and placed them at fixed locations of varying topography in the Cabeza Prieta National Wildlife Refuge, Arizona from August 2003-May 2004. Fix interval affected fix success rates both in our field study (99, 98, 96, 94, 93, 92% fix success rate for 0.25, 0.5, 1, 4, 6, and 13-hour fix intervals, respectively) and in our analysis of data obtained from scientific literature (r2=0.531, P ≤ 0.001), with shorter fix intervals being associated with higher fix success rates. Topography affected the fix success rate (F2, 77=12.017, P ≤ 0.001), location error (F2, 77=6.76, P=0.002), and proportion of 3-dimensional (3-D) fixes (F2, 77=10.184, P ≤ 0.001), resulting in lower fix success rates and larger location errors in areas with more rugged topography. The influence of topography and fix interval on location error and fix success rates may bias GPS location data, resulting in misclassification of habitat use and under-sampling certain areas used by animals. Location error and missing data can increase type II error and may result in incorrect inferences in some studies. These biases need to be assessed and steps should be taken to minimize their influence on results of studies of habitat selection and other aspects of animal ecology.

Efficacy of aerial telemetry as an aid to capturing specific individuals—a comparison of 2 techniques

Long-term investigations of wild ungulates often dictate that telemetry collars on specific individuals be replaced. We described and evaluated the use of aerial telemetry to facil- itate recapture of individual ungulates. Capture of marked animals was much more effi- cient using fixed-wing telemetry when compared to helicopter telemetry. Total time to capture (P=0.012) and pursuit time (P=0.002) differed significantly, but no difference (P = 0.434) in body temperature of mule deer (Odocoileus hemionus) occurred at time of capture. Application of fixed-wing telemetry during net-gun captures of ungulates result- ed in greater safety for capture crews and study animals and in potentially substantial monetary savings.

Neck lesions in ungulates from collars incorporating satellite technology

Wildlife Society Bulletin 2004, 32(3):987–991 Peer edited Investigators have used marking collars and telemetry collars to enhance knowledge about movements of ungulates for many decades. Technological advances have provided increasingly dependable and sophisticated equipment (Fancy et al. 1988; Mourao and Merdi 2002), and methods of collar attachment have evolved substantially, particularly with respect to juvenile ungulates (Smith et al. 1998, Bleich and Pierce 1999). Nevertheless, recent observations of mule deer (Odocoileus hemionus) and mountain sheep (Ovis canadensis) fitted with telemetry collars that incorporate Global Positioning Systems (GPS) and other satellite technology indicate those collars may cause injury to the study animal. The intent of investigators should be to minimize injuries and effects of marking on the behavior of animals (White and Garrott 1990), but our observations suggest lack of compliance in some cases with existing guidelines (Committee on Acceptable Field Methods 1987, Institutional Animal Use and Care Committee [Powell and Proulx 2003]). We placed collars incorporating GPS receivers and very high frequency (VHF) transmitters (Telonics, Mesa, Ariz.; and Posrec, TVP Positioning AB, Lindesberg, Sweden) on mule deer and mountain sheep. We collared female deer in Round Valley, Inyo, and Mono counties, California during March (n=12) and November 2002 (n=1). Four of 6 deer recaptured in November 2002, 2 of 3 recaptured in January 2003, and 2 of 2 recaptured in March 2003 (1 of which was collared in November 2002) exhibited all stages of ulcer formation except bone involvement. Patchy alopecia, nonblanchable erythema, induration, and edema of the intact skin surrounding ulceration were present. In some deer there was only partial skin loss and the ulcers were superficial; others revealed skin loss to the subcutaneous layer resembling a deep abrasion. The most severely affected deer had skin loss with extensive destruction of muscle on the dorsal aspect of the neck (Figure 1). Affected areas varied from 4–100 cm2 and extended from 4–8 cm distal of the occiput or jaw to the mid-cervical region on the dorsal and ventral surfaces of the neck, respectively; lateral surfaces were not involved. We removed collars from the 6 deer that exhibited lesions in November 2002 and January 2003. Three of those animals were recaptured in March 2003, and all lesions had healed completely. As part of long-term ecological investigations (Pierce et al. 2000a,b), we placed VHF collars from 3 manufacturers on 113 juvenile ( 500 adult mule deer of both sexes since 1992. We From the Field: Neck lesions in ungulates from collars incorporating satellite technology

Uncontrolled field performance of Televilt GPS-Simplex™ collars on grizzly bears in western and northern Canada

Commercially available telemetry collars for wildlife that employ Global Positioning System (GPS) devices generally have the ability to gather a large volume of precise location data. We appraised the performance of 12-channel Televilt GPS-SimplexTM collars (Televilt/TVP Positioning AB, Lindesberg, Sweden) deployed across western and northern Canada on grizzly bears (Ursus arctos). Of 71 collar deployments between 2000 and 2002, 38 were retrieved and performed according to their programmed schedule, 20 were retrieved and had some degree of failure, and 13 experienced catastrophic failures and were not retrieved. In addition to these deployments, 10 collars failed predeployment. GPS collar fix success rates were greater for the retrieved collars from the Northwest Territories than for the 4 study areas in British Columbia and Alberta (F4, 50 = 10.82, P < 0.001); thus, the latter areas were grouped for further analyses. Collar fix success rates in the British Columbia and Alberta study areas differed between the retrieved collars that functioned normally (x̄ = 65%, SE = 2.3, n = 28) and collars retrieved with failure events (x̄ = 56%, SE = 4.3, n = 17; t43 = 2.09, P = 0.043). Fix success rates were lower the longer collars were in the field (rs = −0.35, n = 45, P = 0.020). Locations from the GPS collars had a mean dilution of precision of <4 for 2D and 3D locations and thus had a good degree of precision. We were satisfied with the volume and quality of the location data; however, we advise other researchers that significant time and money may be lost troubleshooting problems with the Televilt Simplex system. Other recommendations for future and current users are considered.

Behavioural responses of moose to thermal conditions in the boreal forest

:Among ungulate species living in boreal regions, moose (Alces alces) are most likely to suffer from heat stress since they have a relatively low upper critical temperature (14 °C in summer and -5 °C in winter). We tested the hypothesis that moose adopt behaviours to reduce thermoregulatory costs. We predicted that moose exposed to high intensities of solar radiation or high air temperatures would 1) seek a type of vegetation association that provides thermal shelter and 2) reduce activity. We also predicted that these behaviours would be most evident in summer. Thermal-shelter use and activity of 30 free-ranging moose were measured over 3 y in a 940-km2 study area of boreal forest using GPS telemetry collars. The effect of solar radiation and air temperature on thermal-shelter use and activity were assessed using logistic and multiple regression analyses. Habitat use and activity rates of moose were related to air temperature but not solar radiation. The probability of finding moose in thermal shelters increased with air temperature in summer and fall. Moose activity did not decrease as air temperature increased, but it increased at night during hot periods. As expected, moose response to thermal conditions was most noted in summer. Our results suggest that moose reduce exposure to thermal stress by using thermal shelters during the day and by increasing nocturnal activity. These behavioural adaptations allow moose to cope with thermal stress on a small temporal scale. Negative effects of heat stress could be important in areas where air temperatures are very high for extended periods of time or where thermal cover is scarce.

Effectiveness of spatial mitigation for the George River Caribou Herd within the military training area of Labrador and Québec

The George River Caribou (Rangifer tarandus) Herd (GRCH) regularly migrates through the military Low Level Training Area (LLTA) used for jet training out of 5 Wing Goose Bay, Labrador. Potential disturbance to caribou by military aircraft has been mitigated through the reconfiguration of the LLTA in 1996 away from the traditional migration routes and the establishment of closure areas based on the locations of &amp;gt;20 adults fitted with satellite telemetry collars. In 2000 and 2001, we conducted seven aerial surveys to examine the caribou distribution and abundance within the northern portion and adjacent area of the LLTA during post-calving, summer dispersal, pre-rut and late winter. We flew transects to examine approximately 10% of areas traditionally used during each period. The timing and direction of cari&amp;not;bou movements through this region were similar to that observed in the 1990s. Collared caribou were a good indicator of movements of the GRCH through the LLTA. Closure areas based on the location of satellite collars and direction of movement, were found to enclose the majority of caribou observed within the LLTA. Most GRCH activity now occurs outside the LLTA as a result of reconfiguration.

GPS telemetry of forest elephants in Central Africa: results of a preliminary study

AbstractFew data exist on the ranging behaviour of forest elephants. A feasibility study on the use of GPS telemetry as a tool to study ranging, seasonal movements and distribution was implemented in the Dzanga‐Sangha and Nouabalé‐Ndoki National Parks Complex of Central African Republic and Congo. The study consisted of two parts – a thorough hand‐held testing of an elephant GPS telemetry collar under tropical forest conditions and the deployment of collars on two elephants. During the feasibility study the system performance was satisfactory; GPS fix acquisition success rate, VHF and UHF collar–researcher communications were adequate. Two elephants, a mature bull and an adult female, were immobilized and fitted with GPS collars in October 1998. After deployment, the female's GPS collar performed well initially, but in less than a month the GPS within the collar stopped acquiring fixes. She was subsequently located using VHF tracking. The male was never relocated strongly suggesting complete failure of the collar. Despite these setbacks, the small amount of data retrieved provide an important first insight into forest elephant ranging and daily activity patterns, with significant conservation implications. When technical difficulties of reliability are overcome, GPS telemetry will provide an exceptionally useful tool in forest elephant research and management.

Assuring that 1080 toxicosis in the red fox (Vulpes vulpes) is humane: fluoroacetic acid (1080) and drug combinations

Fluoroacetic acid (1080) is frequently used to poison the introduced red fox (Vulpes vulpes) in Australia. The symptoms of 1080 poisoning in dogs appear extremely distressing to observers as manic running, yelping and convulsing are readily interpreted as being indicative of pain and distress. Assessment of pain perceived by animals poisoned by 1080 is difficult, as severe CNS disruptions alter behaviour and EEG patterns that may otherwise be useful in such assessments. This study compared three drug agents combined with 1080 to address the possibility of pain and distress that may be experienced by foxes during 1080 toxicosis. A mixed-sex group of 15 foxes was used in the trial of each of the three drugs: an analgesic (carprofen; 10 mg kg–1), an anxiolytic/sedative (diazepam; 10 mg kg–1) or an analgesic/sedative (clonidine; 0.75 mg kg–1). Each group of 15 foxes was randomly allocated between three treatments of either 0.5 mg kg–1 of 1080, 0.5 mg kg–1 of 1080 and a dose of the trial drug, and a dose of the trial drug alone. A telemetry collar was used on each fox to monitor the duration and intensity of activity, and behaviour from dosage to death was recorded using daylight/infra-red video cameras. In foxes dosed with 1080 alone, a mean of 4.05 (0.86, P &lt; 0.05) h was observed from dosage to symptoms and 1.57 (0.46, P &lt; 0.05) h from symptoms to death. Diazepam reduced the overall intensity of activity from dosage to death (P &lt; 0.002) and from first symptoms to death (P &lt; 0.05). Diazepam also extended the time until death (P &lt; 0.01) and time taken from dosage to first symptoms (P &lt; 0.01). In the dosages used, clonidine was not as effective as diazepam in reducing activity associated with symptoms of poisoning, although it prolonged the time taken from dosing to first symptoms (P &lt; 0.05). Carprofen did not significantly alter the progression of 1080 toxicosis or the intensity of activity of foxes compared with the group that received 1080 alone. The initial symptoms of 1080 toxicosis include retching and manic running and foxes may be more capable of suffering at this stage than after collapse, where behaviour is likely to be associated with CNS disruption. Diazepam may be effective in minimising any anxiety experienced by foxes especially during the first symptoms of 1080 toxicosis.

Corrigendum: Accuracy of GPS Telemetry Collar Locations with Differential Correction

Corrigendum: Accuracy of GPS Telemetry Collar Locations with Differential Correction

Accuracy of GPS Telemetry Collar Locations with Differential Correction

Global Positioning System (GPS) units in telemetry collars provide an unbiased and precise estimate of animal locations. Under ideal conditions at least 50% of locations are expected to be within 40 m in uncorrected mode GPS, and within 5 m in differential mode GPS. When the collar was placed under open sky, most locations were 3-dimensional locations that could be differentially corrected. Under hardwood canopies with leaves on, the frequency of 3-dimensional locations decreased, the frequencies of failed location attempts and 2-dimensional locations increased, and the precision of GPS locations decreased. We compared the precision of each GPS mode by calculating uncorrected mode and differential mode locations from the same pseudo-range and ephemeris data. We varied the number of satellites used in the location solution to simulate the effect of decreased satellite acquisition due to canopy cover on precision of locations. Precision of locations increased if signals from >4 satellites were used to calculate the location in uncorrected mode and in differential mode. We found that 2-dimensional locations were almost as precise as 3-dimensional positions if the altitude of the GPS unit was known. If the altitude used to calculate a 2-dimensional location was within 50 m of the actual collar altitude, the precision of 2-dimensional differential mode locations was better than 3-dimensional uncorrected mode locations. If the error in altitude was 100 or 150 m, then 50% of 2-dimensional differential mode locations were within 70 m and 95% were within 185 m of the true location. We used GPS locations from collars placed in different cover types and on free-ranging moose (Alces alces) to determine the effect of season, time of day, rainfall, and cover type on GPS performance. On free-ranging moose the collar GPS unit found ≥4 satellites on 52% of location attempts, >50% of locations were 3-dimensional, and >24% of locations were 2-dimensional. Precise tracking of individual animals in all weather throughout the year is possible with GPS telemetry.

Winter peatland habitat selection by woodland caribou in northeastern Alberta

Woodland caribou in northeastern Alberta are relatively sedentary, occur at low densities, and are classed as endangered in Alberta. Increasing encroachment of the forest and petroleum industries into the southern regions of the boreal woodland caribou range has highlighted the need for detailed habitat analysis for this species. We obtained approximately 1000 locations of 47 woodland caribou fitted with very high frequency telemetry collars, providing data on winter habitat use from 1991 to 1994. Telemetry data were combined with digital peatland coverages that best represented lowland habitat diversity. Woodland caribou selected forested fen peatland complexes at both the population and individual spatial scales. Woodland caribou concentrated feeding activity in forested, raised bog islands. The raised bogs provide more xeric substrate for increased lichen biomass, possibly a key factor in their selection during winter. The hypothesized connection between discontinuous permafrost and the maintenance of raised bog islands in terms of caribou forage distribution and availability is discussed.

Evaluation of a helicopter/dart-gun technique for capturing chamois and attaching radio telemetry collars

Abstract The technique of capturing chamois (Rupicapra rupicapra) by firing tranquilliser darts from a helicopter was evaluated. Nine chamois were captured during three operations between September 1976 and May 1977. Animals were tranquillised with the drug fentanyl-azaperone and jumped on from the helicopter. On average, two were caught per hour of operation. Radio transmitters in the 27 MHz frequency band were attached with a collar to each animal. After release animals sought refuge in the forest, but 2 weeks later had resumed normal behaviour. Capture success was attributed to the selection of cool, calm days in spring and autumn when animals occupied open spaces, and to the skill of the helicopter crew in darting and capturing the animals. Important limitations were the stress responses of chamois, the high cost of using helicopters, and a 25% death rate.

Mixed news

Domestic and wild ungulates can exert strong influences on riparian woody vegetation establishment, yet little is known about how wild ungulate herbivory affects riparian restoration in the absence of cattle. We evaluated elk (Cervus elaphus) and mule deer (Odocoileus hemionus) impacts on the establishment of deciduous woody riparian plantings along 11 km of Meadow Creek, a steelhead (Oncorhynchus mykiss) and Chinook (Oncorhynchus tshawytscha) salmon stream in northeastern Oregon, USA. We compared survival and growth between protected and unprotected plantings (from wild ungulates), and assessed the contribution of the plantings to the total deciduous woody cover after two growing seasons. Riparian use by wild ungulates was estimated by tracking a subset of the deer and elk populations using global positioning system telemetry collars. Elk riparian use was 11 times greater than deer, and in contrast to elk, deer were functionally absent from greater than 50% of the restored reach. Wild ungulate herbivory decreased planting survival by 30%, and growth by 73%, and was most detrimental to cottonwood (Populus balsamifera; increased likelihood of mortality by 5 times and suppressed growth by more than 90%). Herbivory impacts resulted in survival rates below regional criteria (50%) for restoration success after only two growing seasons. Naturally recovering shrubs accounted for 99% of the deciduous woody cover, and were mostly composed of the same species or genera as those planted. Our results suggest that wild ungulate herbivory can impede riparian restoration along salmonid streams by suppressing woody plant establishment and recovery.