PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS

The use of natural marks in capture-recapture studies can lead to unequal capture probabilities. This paper examined a catalog of northern bottlenose whale ( Hyperoodon ampullatus ) photographs from the Gully, Nova Scotia, to identify potential sources of heterogeneity. This information can be used to select appropriate individuals and photographs to include in analyses. Individual northern bottlenose whales were sufficiently marked to uniquely identify individuals (= 14.5 marks/individual; range 1-67), but not all mark types persisted over time. Reliable marks were defined as mark types that were not lost over the nine-yeat study period (notches, back indentation, and mottled patches). Individuals were considered reliably marked if they possessed at least one back indentation or mottled patch (located within one dorsal fin width, at the base of the dorsal fin) or a notch on the dorsal fin. Sixty-six percent (SE = 5%) of the population were reliably marked. Longterm analyses (months to years) should use only reliably marked individuals, and the results scaled to account for the rest of the population. Our results also showed that photographic quality affected an observer's ability to identify individuals. For this catalog, quantitative analysis indicated only photographs of Q ≥ 4 (on a 6-point scale with 6 representing the highest quality) should be included in mark-recapture analyses sensitive to heterogeneity.     

利用角形几何特征和计算机视觉技术确定岩羊年龄的新方法

确定野生动物活体年龄是动物种群生态学研究的一项重要基础工作,然而,迄今为止,没有一种传统方法能高效精准地完成这项任务。岩羊角形态复杂且终身生长,其角形随年龄增长和观察角度变化极大。野外条件下,高效获取岩羊个体年龄信息的唯一方法就是拍摄其角的清晰照片。本研究旨在提出一种利用角形几何特征和计算机视觉技术确定野生岩羊活体年龄的新方法,其原理和操作如下:首先建立覆盖全部年龄段(1.5～15.5岁)的已知年龄羊角实体标本的3D模型(左、右角各22个);再在R程序控制下使其在3D空间中旋转,每旋转1°输出一张角形图片;最后计算每张角形输出图片与待定年龄角照片的形状相似性,找出相似性最高的角形图片对应的3D模型,该3D模型的年龄即为待定年龄羊角的实际年龄。30张已知年龄羊角照片的实验验证结果表明,上述年龄鉴定方法能高效地获得精准结果(准确率达100%)。     

Seahorse fingerprints: a new individual identification technique

Individual identification is particularly important for ethological studies and sampling design. Previous studies have developed various types of marking by tags and chemical marks, but these methods involve significant manipulation of the individuals. Other studies have reported natural marks as an efficient method for individual recognition. Our study aims to elucidate a new method for natural mark identification of seahorses, which we tested with the endangered Brazilian seahorse Hippocampus reidi. We avoid pseudoreplication by recognizing individuals. Seahorses have a hard bony structure on the top of their heads called the coronet, which has a different shape for each individual, corresponding to a fingerprint. We tagged seahorses in the field with collar tags and photographed their coronets. After two days, we identified seahorses by their photographs and verified their identification with the collar tags. We correctly identified all individuals by fingerprint identification. Although this method was only tested with adults, we suggest that it applies to seahorses in general, as all species possess the coronet structure.     

Encounter frequencies and grouping patterns of narwhals in Koluktoo Bay, Baffin Island

The narwhal (Monodon monoceros) is a deep diving cetacean with a strictly Arctic distribution. The challenges associated with the remoteness of narwhals have resulted in a lack of knowledge of its social behaviour requiring direct, systematic observations. Bruce Head, a peninsula at the mouth of Koluktoo Bay (Nunavut), provides an exceptional site in Canada for nearshore observation of narwhals during the summer. In this study, we document the movement, timing and grouping patterns of narwhals observed from Bruce Head and how they relate to environmental factors such as the tide and the circadian cycle. Narwhals travelled in clusters of 1–25 individuals of mixed sex and age class. Narwhals entered the bay in bigger clusters than when they exited it. The clusters were part of herds that comprised up to 642 clusters. Narwhal movement patterns were not randomly distributed in time but did not consistently follow the tidal or circadian cycles across years. Bruce Head could host long-term behavioural studies of narwhals to unravel several unanswered aspects of narwhal biology.     

A newt does not change its spots: using pattern mapping for the identification of individuals in large populations of newt species

The correct identification of individuals is a requirement of capture-mark-recapture (CMR) methods, and it is commonly achieved by applying artificial marks or by mutilation of study-animals. An alternative, non-invasive method to identify individuals is to utilize the patterns of their natural body markings. However, the use of pattern mapping is not yet widespread, mainly because it is considered time consuming, particularly in large populations and/or long-term CMR studies. Here we explore the use of pattern mapping for the identification of adult individuals in the alpine (Ichthyosaura alpestris) and smooth (Lissotriton vulgaris) newts (Amphibia, Salamandridae), using the freely available, open-source software Wild-ID. Our photographic datasets comprised nearly 4000 captured animals’ images, taken during a 3-year period. The spot patterns of individual newts of both species did not change through time, and were sufficiently varied to allow their individual identification, even in the larger datasets. The pattern-recognition algorithm of Wild-ID was highly successful in identifying individual newts in both species. Our findings indicate that pattern mapping can be successfully employed for the identification of individuals in large populations of a broad range of animals that exhibit natural markings. The significance of pattern-mapping is accentuated in CMR studies that aim in obtaining long-term information on the demography and population dynamics of species of conservation interest, such as many amphibians facing population declines.     

Eu-social science: the role of internet social networks in the collection of bee biodiversity data

Background

Monitoring change in species diversity, community composition and phenology is vital to assess the impacts of anthropogenic activity and natural change. However, monitoring by trained scientists is time consuming and expensive.

Methodology/Principal Findings

Using social networks, we assess whether it is possible to obtain accurate data on bee distribution across the UK from photographic records submitted by untrained members of the public, and if these data are in sufficient quantity for ecological studies. We used Flickr and Facebook as social networks and Flickr for the storage of photographs and associated data on date, time and location linked to them. Within six weeks, the number of pictures uploaded to the Flickr BeeID group exceeded 200. Geographic coverage was excellent; the distribution of photographs covered most of the British Isles, from the south coast of England to the Highlands of Scotland. However, only 59% of photographs were properly uploaded according to instructions, with vital information such as ‘tags’ or location information missing from the remainder. Nevertheless, this incorporation of information on location of photographs was much higher than general usage on Flickr (∼13%), indicating the need for dedicated projects to collect spatial ecological data. Furthermore, we found identification of bees is not possible from all photographs, especially those excluding lower abdomen detail. This suggests that giving details regarding specific anatomical features to include on photographs would be useful to maximise success.

Conclusions/Significance

The study demonstrates the power of social network sites to generate public interest in a project and details the advantages of using a group within an existing popular social network site over a traditional (specifically-designed) web-based or paper-based submission process. Some advantages include the ability to network with other individuals or groups with similar interests, and thus increasing the size of the dataset and participation in the project.     

Web image search revealed large-scale variations in breeding season and nuptial coloration in a mutually ornamented fish, <Emphasis Type="Italic">Tribolodon hakonensis</Emphasis>

Geographic variations in reproductive traits are important for evolutionary biology, but often difficult to investigate because of the need for a large-scale survey and the ephemeral nature of secondary sexual characteristics. Here, using web image searches (Google Images and Twitter), we revealed large-scale geographic variations (>1500 km) in breeding timing and nuptial coloration in the mutually ornamented fish, Japanese dace (Tribolodon hakonensis). As this fish is easily caught and many anglers upload their photographs on the web, we were able to find a total of 401 high-resolution photographs from all over Japan. Breeding periods were determined from dates of photographs with/without nuptial coloration, which matched with previous studies. We also found that breeding periods might have advanced three weeks over the last 80 years in the Chitose River, potentially because of climate change. Additionally, the pattern of latitudinal cline for breeding timing revealed delayed timing in higher latitudes, although regional variations were also high. Finally, we quantified the patterns of nuptial coloration for this mutually ornamented fish, and confirmed that over 80% of individuals showed typical colorations, but others showed rare phenotypes that were never previously described, including an intermediate coloration between T. hakonensis and a potentially hybridizing species, T. brandtii. Our web-based method for estimating breeding phenology could be adopted for organisms with temporal sexual characteristics, such as plants (e.g., flowering time) and some fishes. Web image analyses are still preliminarily with many limitations, but could be promising for investigating variations in visible traits.     

Effects of leg flags on nest survival of four species of Arctic‐breeding shorebirds

Marking wild birds is an integral part of many field studies. However, if marks affect the vital rates or behavior of marked individuals, any conclusions reached by a study might be biased relative to the general population. Leg bands have rarely been found to have negative effects on birds and are frequently used to mark individuals. Leg flags, which are larger, heavier, and might produce more drag than bands, are commonly used on shorebirds and can help improve resighting rates. However, no one to date has assessed the possible effects of leg flags on the demographic performance of shorebirds. At seven sites in Arctic Alaska and western Canada, we marked individuals and monitored nest survival of four species of Arctic‐breeding shorebirds, including Semipalmated Sandpipers (Calidris pusilla), Western Sandpipers (C. mauri), Red‐necked Phalaropes (Phalaropus lobatus), and Red Phalaropes (P. fulicarius). We used a daily nest survival model in a Bayesian framework to test for effects of leg flags, relative to birds with only bands, on daily survival rates of 1952 nests. We found no evidence of a difference in nest survival between birds with flags and those with only bands. Our results suggest, therefore, that leg flags have little effect on the nest success of Arctic‐breeding sandpipers and phalaropes. Additional studies are needed, however, to evaluate the possible effects of flags on shorebirds that use other habitats and on survival rates of adults and chicks.     

Prediction of Arctic plant phenological sensitivity to climate change from historical records

The pace of climate change in the Arctic is dramatic, with temperatures rising at a rate double the global average. The timing of flowering and fruiting (phenology) is often temperature dependent and tends to advance as the climate warms. Herbarium specimens, photographs, and field observations can provide historical phenology records and have been used, on a localised scale, to predict species’ phenological sensitivity to climate change. Conducting similar localised studies in the Canadian Arctic, however, poses a challenge where the collection of herbarium specimens, photographs, and field observations have been temporally and spatially sporadic. We used flowering and seed dispersal times of 23 Arctic species from herbarium specimens, photographs, and field observations collected from across the 2.1 million km² area of Nunavut, Canada, to determine (1) which monthly temperatures influence flowering and seed dispersal times; (2) species’ phenological sensitivity to temperature; and (3) whether flowering or seed dispersal times have advanced over the past 120 years. We tested this at different spatial scales and compared the sensitivity in different regions of Nunavut. Broadly speaking, this research serves as a proof of concept to assess whether phenology–climate change studies using historic data can be conducted at large spatial scales. Flowering times and seed dispersal time were most strongly correlated with June and July temperatures, respectively. Seed dispersal times have advanced at double the rate of flowering times over the past 120 years, reflecting greater late‐summer temperature rises in Nunavut. There is great diversity in the flowering time sensitivity to temperature of Arctic plant species, suggesting climate change implications for Arctic ecological communities, including altered community composition, competition, and pollinator interactions. Intraspecific temperature sensitivity and warming trends varied markedly across Nunavut and could result in greater changes in some parts of Nunavut than in others.     

Large numbers of marine mammals winter in the North Water polynya

The importance of the North Water polynya in Smith Sound as an overwintering area for marine mammals has been questioned. One way to address the issue is to assess the abundance of selected marine mammals that are present during winter in the North Water. Visual aerial surveys involving double observer platforms were conducted over the eastern part of the North Water polynya in April 2014. Four species of marine mammals were included in strip-census estimation of abundance. Perception bias was addressed using a double-platform survey protocol, a Chapman mark–recapture estimator for whales, seals and walruses (Odobenus rosmarus) on ice and a mark–recapture distance sampling estimation technique for walruses in water. Availability bias was addressed by correcting abundance estimates by the percentage of time animals detected in water that were available for detection at the surface. The resulting estimates suggested that 2544 walruses (95 % CI 1513–4279), 6005 bearded seals (Erignathus barbatus, 95 % CI 4070–8858), 2324 belugas (Delphinapterus leucas, 95 % CI 968–5575) and 3059 narwhals (Monodon monoceros, 95 % CI 1760–5316) wintered in the eastern part of the North Water polynya in April 2014. The walrus estimate is larger than previous summer estimates, and it emphasizes the importance of the habitat along the Greenland coast as a walrus wintering ground. The estimate of belugas is likely negatively biased due to the partial coverage of the potential habitat. The estimate of narwhals is large compared to the few previous observations of narwhals in winter in the North Water, and it demonstrates that large numbers of narwhals winter there. The overall conclusion is that the North Water is indeed an important wintering area for at least walruses, belugas, narwhals and bearded seals.     

A SIFT-based software system for the photo-identification of the Risso's dolphin

Photo-identification is a commonly used non-invasive technique that has been profitably employed in biological studies throughout the years. It starts from the assumption that a single individual can be recognized in multiple photos captured at different times by exploiting its unique representative and visible physical qualities such as marks, notches or any other definite feature. Hence, photo-identification is performed to infer knowledge about wild species' spatial and temporal distributions as well as population dynamics, thus providing valuable information especially when the species being investigated is ranked as data deficient. Furthermore, the technological improvements of the last decades and the large availability of devices with powerful computing capabilities are driving the research towards a common goal of enriching bio-ecological studies with innovative computer science approaches. In this scenario, computer vision plays a fundamental role, as it can successfully assist researchers in the analysis of large amounts of data. The aim of this paper is, in fact, to effectively provide a computer vision approach for the photo-identification of the Risso's dolphin, exploiting specific visual cues with a feature-based approach relying on SIFT and SURF feature detectors. The experiments have been conducted on image data acquired in the Gulf of Taranto from 2013 to 2017, conducting a comparative analysis of the performance of both SIFT and SURF, as well as a comparison with the state-of-the-art software DARWIN, and they proved the effectiveness of the proposed approach and suggested its application would be suitable to large scale studies. In conclusion, this paper shows an innovative computer vision application for the identification of unknown Risso's dolphin individuals that relies on a feature-based automated approach. The results suggest that the proposed approach can efficiently assist researchers during the photo-identification task of large amounts of data collected in such a challenging domain.     

Genetic fingerprinting proves cross‐correlated automatic photo‐identification of individuals as highly efficient in large capture–mark–recapture studies

Capture–mark–recapture (CMR) approaches are the backbone of many studies in population ecology to gain insight on the life cycle, migration, habitat use, and demography of target species. The reliable and repeatable recognition of an individual throughout its lifetime is the basic requirement of a CMR study. Although invasive techniques are available to mark individuals permanently, noninvasive methods for individual recognition mainly rest on photographic identification of external body markings, which are unique at the individual level. The re‐identification of an individual based on comparing shape patterns of photographs by eye is commonly used. Automated processes for photographic re‐identification have been recently established, but their performance in large datasets (i.e., > 1000 individuals) has rarely been tested thoroughly. Here, we evaluated the performance of the program AMPHIDENT, an automatic algorithm to identify individuals on the basis of ventral spot patterns in the great crested newt (Triturus cristatus) versus the genotypic fingerprint of individuals based on highly polymorphic microsatellite loci using GENECAP. Between 2008 and 2010, we captured, sampled and photographed adult newts and calculated for 1648 samples/photographs recapture rates for both approaches. Recapture rates differed slightly with 8.34% for GENECAP and 9.83% for AMPHIDENT. With an estimated rate of 2% false rejections (FRR) and 0.00% false acceptances (FAR), AMPHIDENT proved to be a highly reliable algorithm for CMR studies of large datasets. We conclude that the application of automatic recognition software of individual photographs can be a rather powerful and reliable tool in noninvasive CMR studies for a large number of individuals. Because the cross‐correlation of standardized shape patterns is generally applicable to any pattern that provides enough information, this algorithm is capable of becoming a single application with broad use in CMR studies for many species.     

Using age grading by wing injuries to estimate size-dependent adult survivorship in the field: a case study of the yellow dung fly Scathophaga stercoraria

Abstract 1. Studies of natural selection depend on estimates of longevity and mortality in the wild. In small and mobile species such as insects, direct, mark–recapture (resight), studies are difficult to perform because individuals cannot be tracked easily.
2. It was investigated whether age grading based on wing injuries alone can be used to estimate size-specific survivorship in the field in the yellow dung fly Scathophaga stercoraria (L.) (Diptera: Scathophagidae).
3. The accumulation of different types of wing injury throughout the spring and autumn flight seasons for both sexes was recorded: tears, notches (both reflecting regular wear), and large missing areas (probably due to intra- and inter-specific interactions).
4. Female longevity increased with body size in both spring and autumn, whereas male longevity increased slightly with size in spring but decreased in autumn.
5. The two sexes and males of different size classes accumulated the various types of wing injury differentially, presumably due to differential patterns of intraspecific interactions. Additionally, body size exhibited a seasonal pattern, complicating interpretation of the relationship between body size and wing injuries.
6. It is therefore concluded that estimating adult viability selection on body size using wing injuries is problematic in dung flies, and potentially also in other species. It is suggested that before this method is applied in any particular species, pilot studies should be conducted to verify whether wing injuries accumulate equally in all classes of individuals of interest. In addition, it is necessary to investigate the causes of different types of wing injury.     

Male and Female Meadow Voles,Microtus pennsylvanicus,Differ in Their Responses to Heterospecific/Conspecific Over‐Marks

Voles use runways, paths, and trails that may also be used by rabbits and mink. These shared areas could contain the scent marks of conspecifics and heterospecifics. Thus, it is likely that the scent marks of heterospecifics may overlap or be overlapped by those of voles, forming over‐marks. Much is known about how voles respond to over‐marks of two different conspecifics. However, we do not know how they would respond to an opposite‐sex conspecific whose scent marks are in an over‐mark with the scent marks of predator or the scent marks of a non‐predator heterospecifics. We tested the hypothesis that meadow voles, Microtus pennsylvanicus, differ in their response to the scent mark of the opposite‐sex conspecific if the scent mark was overlapped by that of a mink, a vole predator, or rabbit, a vole non‐predator. We found that female but not male voles showed a preference for the scent marks of the opposite‐sex conspecifics that were part of the mink‐vole over‐mark when compared to those of opposite‐sex conspecifics that were not part of the over‐mark. This preference by female voles was independent of whether the male vole was the top‐scent donor or bottom‐scent donor of the over‐mark. Male and female voles showed no preference between the scent marks of the opposite‐sex conspecifics whose marks were part of or not part of the rabbit‐vole over‐mark. Sex differences in the manner that meadow voles respond to rabbit‐vole and mink‐vole over‐marks are discussed.     

Significant decrease in local butterfly community during the last 15 years in a calcareous hill of the middle Korea

Recently the significant decreases of species richness and abundance among terrestrial animals including butterflies are reported due to habitat change, overexploitation, and global warming. We compared the butterfly species composition and abundance from 1999 and 2014–2015 in a calcareous hill site of the middle part of Korea using a line transect method. There was a significant decrease in the number of individuals (abundance) and the number of species (richness) from 1999 to 2014–2015. This decrease was more prevalent among northern species than southern species, and the local extinct species were more prevalent among northern species, showing the influence of global warming on butterfly assemblages. However, no impact of habitat change was observed because of maintenance of the grasslands, which is caused by the dry soils of the calcareous region.     

Vertical and Temporal Patterns of Biodiversity of Fruit-Feeding Butterflies in a Tropical Forest in Uganda

Quick surveys are often used by conservation biologists to assess biodiversity. In tropical forests, fruit-feeding butterflies are a convenient indicator group because they can be readily trapped and are comparatively easy to identify. However, studies carried out in Costa Rica and Ecuador have revealed that long-term sampling is needed to estimate biodiversity accurately. Furthermore, almost half of the biodiversity of fruit-feeding butterflies in the neotropics was found to be in the canopy. Short term sampling in the understory can, therefore, lead to inaccurate estimates of species richness and worse, to poorly informed conservation decisions. Comparable to the studies in South America, we performed a long-term trapping study of the same guild of butterflies in the understory and canopy of Kibale Forest in Uganda, to describe temporal and vertical patterns of biodiversity. We caught 32,308 individuals of 94 species over three years. About 14% of these species could be categorized as canopy specialists and 68% as understory specialists. Temporal variation was extensive and did not follow a clear seasonal pattern. This is the first study in an African forest with continuous sampling of fruit-feeding butterflies over multiple years and in both canopy and understory.     

Digital Photography Improves Consistency and Accuracy of Bat Counts in Hibernacula

ABSTRACT The size and distribution of measurement errors associated with major techniques for estimating numbers of hibernating bats are unstudied, although this is the principle method of enumerating several endangered bat species. However, decisions concerning the listing status of a species under the Endangered Species Act require consistent and accurate estimation of population size and trends. Recent advances in digital photography have improved the ability to produce a quantitative record of the numbers of bats in hibernacula. We surveyed clusters of Indiana bats in a hibernaculum and compared results from counts of digital photographs of clusters to results from 4 variations of visual estimation. We counted bats in photographs using Geographic Information System digitization over the photograph. Total counts from 2 sets of photographs varied by <1.5%. Nonphotographic estimation techniques varied from 76% to 142% of counts from photographs for clusters for which estimation (rather than counting) was used. Where feasible, photography can improve status and trend information for species of concern, permitting more timely and specific management actions.     

A Novel Method of Assessing Dominance Hierarchies Shows Nuance,Linearity and Stability in the Dinosaur Ant Dinoponera quadriceps

Many social species with relatively simple societies have dominance hierarchies of individuals, with dominant individuals achieving fitness and subordinate individuals either queuing to obtain fitness or achieving only indirect fitness by helping relatives. Assessing the dominance hierarchy in a social group is generally based upon observing dyadic interactions as and when they occur spontaneously within the whole‐group setting. However, this method can be very time‐consuming because many dyads interact only very rarely, necessitating either extremely long observation periods or many dyadic relationships being unresolved. Here, we report an alternative method using the queenless dinosaur ant Dinoponera quadriceps, which lives in colonies containing tens of individuals. We removed all individuals from their nest and observed the dominance behaviours expressed in isolated dyadic interactions for every pairwise combination of individuals. Individuals showed a classic dominance behaviour in this setting, and the rapid nature of the assay allowed us to observe every dyadic relationship on a weekly basis over 4 weeks. The dominance hierarchies based on these isolated dyadic interactions correlated well with those produced by the conventional method of colony observations. They showed the hierarchies to be highly linear and stable, and also revealed that dominance relationships may extend further down the hierarchy than previously thought. Although highly manipulative, the isolated dyadic interaction method works well and will likely make more feasible the study of other social species in which pairs of individuals can be isolated together.     

Seasonal cycles of species diversity and similarity in a tropical butterfly community

1. Studies of seasonality in ecological diversity rarely extend over more than a few years, and few studies of seasonal diversity have explicitly investigated the influence of environmental factors on seasonal community composition, especially in tropical communities. 2. Our 10 years of monthly sampling in Amazonian Ecuador yielded 20 996 individuals of 137 fruit-feeding butterfly species. Seasonal cycles of rainfall drive annual cycles in species diversity and community similarity. Undetermined processes operating most strongly during the dry season maintain species diversity and high community similarity across years. 3. Seasonal cycles in community diversity and similarity are superimposed on a gradual decline in similarity between community samples on a decadal time-scale because of long-term changes in species abundances. 4. Monitoring and analysis of changes in community composition over a range of time-scales can be used to refine models of community dynamics by incorporating environmental factors necessary to predict the ecological impact of future climate change.     

Estimating narwhal (Monodon monoceros) age using tooth layers and aspartic acid racemization of eye lens nuclei

Counting growth-layer groups (GLGs) in teeth is one of the most precise and widely accepted methods for aging marine mammals. Male narwhals have a large erupted tusk that can be used for aging, but this tusk is often difficult or expensive to obtain from hunters and most females do not display the tusk; thus, alternative methods for narwhal aging are needed. In this study, we aged narwhals by counting annual GLGs in embedded tusks and by measuring the change in the ratio of D- and L-enantiomers of aspartic acid in the eye lens nucleus that occurs as the animal ages (the aspartic acid racemization [AAR] technique). Absolute age estimates were estimated for seven tusks aged ≤15 yr. Estimated age was a significant predictor of aspartic acid D/L ratios with a racemization rate (K_asp) of 9.72 × 10⁻⁴/year ± 2.28 × 10⁻⁴ and a (D/L)₀ of 3.46 × 10⁻² ± 1.78 × 10⁻³ (r² = 0.74). Results from our study, which included more younger GLG-aged animals than previously evaluated, confirms AAR can be used to generate age estimates for narwhals.