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NICHOLAS P. MCCANN RON A. MOEN GERALD J. NIEMI 《The Journal of wildlife management》2008,72(4):955-958
Abstract: We calibrated snowshoe hare (Lepus americanus) numbers with pellet counts in Minnesota, USA, to understand the relationship between hare numbers and pellets in the central portion of the hare range. We found a strong and significant correlation between hare numbers and pellet counts using either linear or functional regression with either annual or semiannual pellet counts. Equations we developed using linear or functional regression predicted >1 hare/ha at similar pellet-density thresholds. These equations can be used to efficiently identify habitats that support hare numbers necessary for Canada lynx (Lynx canadensis) persistence in Minnesota. 相似文献
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André H. Zambolli Maria Carolina R. Manzano Laura Kyoko Honda Gabriela C. Rezende Laurence Culot 《American journal of primatology》2023,85(1):e23454
Information about species distribution is important for conservation but the monitoring of populations can demand a high sampling effort with traditional methods (e.g., line transects, sound playback) that are poorly efficient for cryptic primates, such as the black lion tamarin (Leontopithecus chrysopygus). Here we investigated the effectiveness of passive acoustic monitoring (PAM) as an alternative method to identify the presence of vocalizing lion tamarins in the wild. We aimed to: (1) determine the maximum distance at which autonomous recorders (Song Meter 3) and Raven Pro acoustic software can respectively detect and identify lion tamarin long calls emitted by two captive subjects (ex situ study); and (2) determine the sampling effort required to confirm the presence of the species in the wild (in situ study). In captive settings, we recorded lion tamarin long calls with one to two autonomous recorders operating at increasing distances from the animals' enclosure (8−202 m). In a 515 ha forest fragment, we deployed 12 recorders in a grid, 300 m apart from each other, within the estimated 100 ha home range of one group, and let them record for 10 consecutive days, totaling 985 h. In the ex situ study, hand-browsing of spectrograms yielded 298 long calls emitted from 8 to 194 m, and Raven's Template Detector identified 54.6% of them, also emitted from 8 to 194 m. In the in situ study, we manually counted 1115 long calls, and the Raven's Template Detector identified 44.75% of them. Furthermore, the presence of lion tamarins was confirmed within 1 day using four randomly sorted recorders, whereas 5 days on average were necessary with only one device. While specific protocols still need to be developed to determine primate population size using this technology, we concluded that PAM is a promising tool when considering long term costs and benefits. 相似文献
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DANIEL GALLANT LIETTE VASSEUR CELINE H. BÉRUBÉ 《The Journal of wildlife management》2007,71(1):258-265
Abstract: We examined the relationship between the production of sites with feces (i.e., latrines) and river otter (Lontra canadensis) abundance to determine whether scat surveys were adequate for monitoring relative population size for species leaving activity signs in a clumped distribution on the landscape. We conducted winter riparian transects to simultaneously monitor otter abundance via snow tracks and latrine sites along the rivers of Kouchibouguac National Park and surrounding area in New Brunswick, Canada. Our data showed that latrine abundance poorly reflected otter abundance for given stretches of rivers because the relationship was nonlinear and reached a plateau. The number of latrine sites was not related to the time period since last snowfall, which indicated that otters repetitively defecated at the same sites. Individual otters and groups did not produce activity signs over larger distances as a function of time, which indicated that they tend to stay in their home ranges in winter. We discuss why scat survey protocols based on determining presence—absence of a species at predetermined search sites may poorly reflect population size, as well as population fluctuations in time. Caution is advised when interpreting data from such surveys for species for which feces or other activity signs surveyed play a role in intraspecific communication and tend to be in a clumped distribution on the landscape. 相似文献
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JOHN E. MCDONALD JR. 《The Journal of wildlife management》2008,72(7):1461-1462
Abstract The southern extent of the range of Canada lynx (Lynx canadensis) extends into the contiguous United States in locations from Washington State in the West to northern Maine in the East. Lynx persist in various habitats across this range from high-elevation wilderness to intensively managed industrial forests. Lynx habitat use at the species' southern range boundary was poorly understood before the species was listed as Threatened under the Endangered Species Act in 2000, because most research had been conducted in boreal forest. The papers in this special section outline a variety of questions regarding lynx populations at the southern extent of their range, address topics on lynx space use and denning habitat, and provide generally consistent results in terms of features important to lynx habitat use despite the wide variation in specific habitats among the study areas. 相似文献
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JESSICA A. HOMYACK DANIEL J. HARRISON WILLIAM B. KROHN 《The Journal of wildlife management》2007,71(1):4-13
Abstract: Snowshoe hares (Lepus americanus) are an important prey species and a dominant herbivore across much of their North American range, and researchers have questioned the influences of forestry practices that alter habitat for hares and the potential community-level effects on carnivores. We examined the effects of precommercial thinning (PCT) from 1 to 11 years posttreatment on snowshoe hares. In the commercial forests of northern Maine, USA, we counted and cleared hare pellets twice a year during 2001 and 2002 on >46 km of pellet transects across 30 regenerating conifer stands (17 treated with PCT) previously treated with an aerial application of herbicide. We compared densities of snowshoe hare pellets among 3 development classes with (1 yr after thinning, 6 yr after thinning, and 11 yr after thinning) and without thinning (stands with a similar history of clearcut and herbicide treatment but no thinning). During both years, densities of hares were lower in stands treated with PCT than in similar unthinned stands across the 3 development classes and during both leaf-off and leaf-on seasons (P < 0.001). Within both thinned and unthinned stands, hare density was greatest in stands in the 1-year development class when compared to the 6-year and 11-year development classes, but a statistical difference (P = 0.048) among classes was evident only during leaf-off seasons. Precommercial thinning was associated with densities of snowshoe hares that were approximately half of those in similar unthinned stands up to at least 11 years posttreatment; however, thinned stands may retain densities of hares greater than stands managed using other forest harvesting regimes. Our results apply to core portions of stands with crop trees spaced at 1.8–2.4-m intervals following complete overstory removal and herbicide treatment. We advocate caution when applying our results to other thinning regimes or across broader spatial scales. 相似文献
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Joseph W. Hinton Alicia E. Freeman Véronique St-Louis Louis Cornicelli Gino J. D'Angelo 《The Journal of wildlife management》2020,84(5):957-967
Understanding space-use patterns by elk (Cervus canadensis) is essential to alleviating human-elk conflicts, particularly when crop depredation by elk can make it harder to justify to the public the need to restore elk populations to regions with agricultural landscapes. In 2016–2017, we used global positioning system data from 20 female elk to investigate their selection for agricultural cover during the agricultural season (1 May–31 Oct) in northwestern Minnesota, USA. We estimated resource selection functions with resource availability defined at the home range scale. Elk space use was primarily determined by distance to forest cover in areas proximate to agricultural fields. During diurnal periods, elk selected areas with forest cover near agricultural fields planted with legumes and cereal. During nocturnal periods, elk selected for agricultural fields with little to no canopy and that were planted with legumes. We suggest that management of elk in northwestern Minnesota will require practices that discourage the use of agriculture by elk while improving natural habitats within areas managed for elk restoration. We suggest that forestry practices (i.e., thinning and burning) could improve cover and forage openings for elk in restoration areas. Furthermore, managers could work with agricultural producers where elk occur to plant crops favored by elk (i.e., legumes) outside known home ranges and plant fields within home ranges with crops that elk avoided (i.e., hay). Collectively, these practices may shift the ranges of elk herds into restoration areas and lower conflict between the public and elk restoration efforts. © 2020 The Wildlife Society. 相似文献
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RON MOEN CHRISTOPHER L. BURDETT GERALD J. NIEMI 《The Journal of wildlife management》2008,72(7):1507-1513
Abstract Establishing whether conditions are suitable for reproduction would help determine if immigration is necessary for Canada lynx (Lynx canadensis) to persist at the southern edge of the species range. We located den sites and monitored reproduction of radiocollared lynx in Minnesota from 2004 to 2006. Movement rates of denning females measured with Global Positioning System collars were similar to movement rates of lynx elsewhere. Female lynx with kittens used different habitat types in predenning, denning, and postdenning periods. Landscape composition at the scale of the foraging radius around a den site contained more lowland conifer, upland conifer, and regenerating forest than did home ranges or the area used by radiocollared lynx in Minnesota, USA. We used the spatial distribution of cover-type composition around known den sites to predict and map potential denning habitat in northeastern Minnesota. Techniques for identifying the spatial distribution of suitable denning habitat provide a biological basis for management actions that could enhance recovery of Canada lynx populations in the southern part of the species range. 相似文献
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伴随城市人口快速聚集及人类活动加剧,城市生态环境质量及其对人类社会经济发展的支撑能力正在受到严重挑战,城市生态系统及其变化的研究越来越受到重视,国内外涌现出大量城市生态学长期监测工作,但相关监测方法的讨论还很少。在分析城市生态学长期监测类型和实践经验基础上,从城市面临的环境胁迫和建设管理需求出发,构建了城市生态学长期监测的\"胁迫+需求-生态系统响应\"总体思路框架;从科学上最基本和社会上最关心的城市生态系统要素、格局和过程着眼,提出城市生态学长期监测的7项内容(土地覆盖与利用、人居环境质量、生物多样性、生物质生产、水文过程、生物地球化学循环和物质代谢);并分析了城市生态学长期监测的4种方法(遥感监测、仪器监测、调查监测、公众科学监测),分析了城市生态学长期监测单元及其空间布局及监测频率。这将为我国城市生态学长期监测工作开展提供方法论基础和实践参考。 相似文献
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Nathalie van Vliet Ewa Kaniowska Mathieu Bourgarel Christian Fargeot Robert Nasi 《African Journal of Ecology》2009,47(3):393-399
In several regions of the Congo Basin the call of an endangered duiker is traditionally used by hunters to attract animals. We explore the possibility to standardize this call method to improve day time transect counts. Our study shows that the call is particularly efficient for the most common duiker species [ Philantomba monticola (previously Cephalophus monticola ), Cephalophus callipygus and Cephalophus dorsalis ]. The call increases the number of direct sightings in secondary forests and counterbalances the bias caused by vegetation density in classic day time counts. The method is more effective during the first 4 min of the call and from 9.00 to 11.00 hours, particularly during the dry season. Hunting using the call does not significantly increase the sex bias (more males killed) obtained without the call. Compared with day time visual counts, the call method ensures a more reliable species identification because animals are better seen and for a longer time. Derived from a traditional practice, the call can be easily appropriated by local communities in participatory duiker surveys. However, the method is not recommended when multi-species surveys are to be carried out or when densities are to be estimated because the area surveyed per unit call is unknown. 相似文献
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《水生昆虫》2012,34(2):33-43
Detailed faunistic data originating from four sampling series of aquatic Heteroptera (Nepomorpha) in the Lake Balaton (the largest shallow lake of Central Europe) between 1928 and 2002 were analysed. A comparative analysis confirmed that the aquatic bug fauna of this great lake can be established with suitable accuracy if it is sampled by different but devoted collectors. So far 26 species of aquatic bugs have been reported from here. The fauna changed considerably during the seven decades. Species lists of the four basins of the lake established during the four sampling periods show characteristic differences. Not only the frequency of four Micronecta species (Micronecta griseola, M. pusilla, M. scholzi, M. minutissima) changed characteristically but there has been a distinct change in the ratio of rare species too. Rare species were present in significantly higher proportion in the period 1928–1930 than in any of the later samplings between 1984 and 2002. All these changes run parallel with the direction of anthropogenic influences. 相似文献
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Monitoring the abundance of cryptic species inevitably relies on the use of index methods. Unfortunately, detectability is often confounded by unidentified covariates. One such species is the critically endangered Australasian Bittern Botaurus poiciloptilus. Current monitoring relies upon the ability to count males based on the conspicuous breeding calls of males. However, as in many vocal species, calling rates vary spatially and temporally, making it necessary to account for this when using call counts to index abundance. We undertook 461 15‐min call counts of Australasian Bitterns, in a range of conditions, during two breeding seasons at Whangamarino wetland, New Zealand. We fitted a range of generalized linear mixed models to these data to determine which factors were the best predictors of calling rate per individual Bittern (CRPI), allowing us to make recommendations regarding the optimum time and conditions for monitoring. Bittern CRPI was predictable in terms of time of day, month, cloud cover, rainfall and certain moon parameters, but some spatial and temporal variation remained unexplained. Results showed that the best time to detect Australasian Bitterns was 1 h before sunrise, in September (austral spring), on a moonlit night with no cloud or rain. Such models are useful for identifying times and conditions when counts are the highest and least variable, and could be applied to any species or cue count monitoring method where detection depends on counting calling individuals. Results can be used to standardize index counts, or sensibly to adjust and compare counts from different times. Standardizing monitoring in this way can lead to the development of monitoring methods that have a greater power to show population changes across shorter time periods. Moreover, the use of modelling processes to estimate effect sizes creates potential for such methods to be applied in circumstances where monitoring conditions are rarely optimum and standardization creates logistical trade‐offs, something that is particularly common in studies of cryptic species. 相似文献
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Emily L. Weiser Jay E. Diffendorfer Laura Lpez‐Hoffman Darius Semmens Wayne E. Thogmartin 《Ecography》2019,42(4):836-844
Long‐term, large‐scale monitoring programs are becoming increasingly common to document status and trends of wild populations. A successful program for monitoring population trend hinges on the ability to detect the trend of interest. Power analyses are useful for quantifying the sample size needed for trend detection, given expected variation in the population. Four components of variation (within‐year variation at a given site, interannual variation within a site, variation among sites in the interannual variation, and variation among sites in mean abundance or density) are commonly considered in power analyses for population trend, but a fifth is rarely considered: variation among sites in the local trend. Spatial variation in trend is expected to reduce statistical power, but the magnitude of this reduction has not been fully explored. We used computer simulations to evaluate the consequences of ignoring spatial variation in trend under a variety of sampling designs and wide ranges of other components of variation. The effect of spatial variation in trend on power was minor when other input parameters took extreme values that made the trend either very difficult or very easy to detect. However, at moderate values of the other parameters, spatial variation in trend had a strong effect, reducing statistical power by up to 60%. In some cases, ignoring spatial variation in trend resulted in an 80% probability of a type I error (falsely detecting a trend in a stable population). Spatial variation in trend is therefore an important consideration when designing a long‐term monitoring program for many species, especially those affected by local conditions at sites that are repeatedly surveyed. If variation in trend is ignored, as in many previous power analyses, the recommended sampling design will likely be insufficient to detect the trend of interest and lead to potentially false conclusions of a stable population. 相似文献
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Ian A. N. Stringer G. Richard Parrish Greg H. Sherley Darryl I. MacKenzie 《Molluscan research.》2014,34(3):155-175
The large land snail Placostylus ambagiosus (Pulmonata: Bulimulidae) was studied in northernmost New Zealand from 1988 to 2004. At Cape Maria van Diemen (CMvD), more juveniles than adults were found, although estimates showed adults as the most abundant. A cohort, hatched after rodent control commenced in 1990, began maturing in 1995, but 89% died by 1997 (partly through competition with garden snails, Cornu aspersum), before numbers partially recovered by 2003. At Surville Cliffs, adults were estimated to be more abundant than juveniles but few juveniles were observed. Numbers under 12 food plants fluctuated between 425 and 657. Many snails dispersed after horses (Equus caballus) partially defoliated their food plants but returned once these recovered. A translocated population increased after rodent control commenced in 1999, but declined when rodent control ceased in 2002. Another translocated population declined when rodents were present and never recovered even after rodent control commenced in 2002. Snails took 2.8–11.7 years to mature from half-grown juveniles depending on location. Estimated adult life expectancies were 5.2 years at CMvD and 10.0 years at Surville Cliffs. Small juvenile snails experienced the highest mortality, and snails that moved between food plants experienced increased mortality. These results are discussed in relation to conservation management. 相似文献
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Group-living primates monitor group members to maintain the spatial cohesiveness of the group. We examined the possibility that visual scanning (turning the head for more than 3 sec) and contact calls (coo calls) function as visual and auditory monitoring behaviors to avoid separation from group members in wild Japanese macaques. The rate of visual scanning increased as proximity to group members decreased and as mobile activities (foraging and moving) increased, compared with immobile activities (resting and grooming). However, the rate of contact calls varied differently with proximity and activities. During resting and moving, the rate of contact calls increased as proximity decreased. In contrast, the rate increased with closer proximity during feeding. Visual scanning during all activities and contact calls during resting and moving increased when the group members were likely to spread over a larger area, suggesting that these behaviors functioned as monitoring of group members to avoid separation from the group. Contact calls also increased when the group members stayed in close proximity during foraging, suggesting that this behavior was also associated with competitive situations. Contact calls may also function to ease tension or maintain distance to avoid conflict in competitive situations. 相似文献
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Donald J. Brown Madaline M. Cochrane Ron A. Moen 《The Journal of wildlife management》2017,81(5):868-877