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Female of Carabus coriaceus with attached radio transmitter (a). Trajectories (1–6) decoded by the Viterbi algorithm into two movement states noticeably differed in their shapes between DB (b) and GPS (c) recording methods
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Movement trajectories are usually recorded as a sequence of discrete movement events described by two parameters: step length (distance) and turning angle (bearing). One of the most widespread methods to record the geocoordinates of each step is by a GPS device. Such devices have limited suitability for recording fine movements of species with low...
Citations
... This transect was extended during the 2022 flight season to document outliers/migrants from the release area (Fig. 2). A distance-bearing protocol Růžičková and Elek 2021) was employed to accurately record Flight Point locations. A one-meter accurate position fix was obtained using a pole-mounted Bad Elf Surveyor BE-GPS-3300 GNSS receiver to establish a fixed reference point as close as Fig. 2 Astley Moss site plan generated in QGIS using Environment Agency LIDAR imagery as a base layer with a 1 m horizontal and 10 cm vertical resolution. ...
The two main goals of peatland restoration are habitat improvement and climate change mitigation by reducing greenhouse gas emissions from damaged peatlands and providing a net carbon sink. The biodiversity of specialist peatland species is threatened because of habitat destruction and the large heath butterfly Coenonympha tullia has become a flagship species for peatland ecosystem restoration, with a species reintroduction programme currently underway on a peatland restoration site within Chat Moss, Greater Manchester, UK. The aim of this study was to improve our quantitative understanding of C. tullia habitat resource requirements to optimise habitat restoration for further reintroduction attempts. We monitored butterfly micro-distribution and dispersal during the first three flight seasons (2020, 2021 and 2022) of the reintroduction using high-accuracy GPS, combined with a distance-bearing protocol. Analysis of butterfly flight points and rest points in relation to plant species distribution and abundance, identified the most important habitat resources. Using logistic regression, treatment-response curves were constructed, enabling us to identify critical thresholds for the abundance of these important habitat resources. The break of slope near the top of the logistic curve was identified using segmented regression, giving an estimate of the near-optimal abundance; fourteen Eriophorum vaginatum tussocks per 2 m quadrat and 13.4% Erica tetralix cover.
Implications for insect conservation
During ecosystem restorations, prior to the reintroduction of species with specialist habitat requirements, it is necessary to have a clear understanding of the abundance of the important habitat resources that need to be provided. The quantitative approach we describe defines the most significant environmental factors and habitat resources, then uses segmented regression to estimate the near-optimal habitat resource requirements; increasing the likelihood of reintroduced populations thriving and reintroduction programmes achieving long-term success.
... Finally, it should be noted that the results obtained in this study are based on the location of individuals using a GPS device with an accuracy of ~ 2 m, which may bias to some extent the results of the subtle movements detected in this endemic bush-cricket. In a fine scale movement tracking study, statistically significant measurement errors of the GPS approach were observed for distances and bearings (Růžičková and Elek 2021). Distances measured by GPS (with an accuracy of ~ 3 m) were approx. ...
... The shorter the distance covered, the greater the relative error, and the average bearing error of GPS was evenly distributed over all directions. These errors were larger under a dense forest canopy (Růžičková and Elek 2021). The implications of these findings are case specific and depend on the objective of the study. ...
Knowledge on the mobility of threatened species is a clue to understanding population dynamics and is needed to develop appropriate conservation strategies. Here, we investigate movement patterns of the Bei-Bienko’s Plump Bush-cricket (Isophya beybienkoi), an example of a flightless and critically endangered species endemic to the Slovak Karst (southern Slovakia, Central Europe). The capture-mark-recapture method was used to estimate the mobility of the species using fluorescent dye as a marking medium. We found that the mean (± SD) daily distance travelled by this species was only 3.2 ± 2.6 m, with significant differences between males (4.1 ± 3.0 m) and females (2.7 ± 2.1 m). Our results indicate that I. beybienkoi is a short-distance disperser. Males disappeared faster than females from the study plots (at maximum, two females were recaptured even after 41 days). The observed movement patterns suggest that the most urgent conservation measure for this species is to improve the habitat quality of sites, which suffer from overgrowth, and to maintain the quality of other suitable sites that might increase the size of the existing subpopulations.
Our results show that I. beybienkoi is a short-distance disperser and wanders only within its optimal habitat. Hence, to incorporate movement behaviour into conservation, one of the measures that should mitigate this threat is to preserve or improve the quality of habitats that suffer from overgrowth, in order to increase the size of existing subpopulations. The observed movement patterns suggest that the species is probably incapable of responding to changes in the availability of suitable habitats by dispersing, indicating a limited exchange of individuals between isolated populations. Thus, to enhance structurally diverse mosaic of high-quality habitats, restoration of migration corridors former used as movement corridors for grazing animals may support the dispersal of the threatened bush-cricket.
... Every 4 h, all individuals were detected and their new position marked with a labelled pole. We recorded the time, the distance travelled since release with a decametre and the direction taken since release (deviation from compass direction, distance-bearing approach (Rùžièková and Elek, 2021) with the compass application of a smartphone (using a single iPhone 5S to avoid bias). This provided two daily time steps per time of day: afternoon (10: 30-14:30, 14:30-18:30), night (18:30-22:30, 22:30-2:30), morning (2:30-6:30, 6:30-10:30). ...
Better understanding insects’ movements could help preserve and restore the insect communities that are key to the functioning of grasslands. Recent technological advances have led to spectacular achievements in movement ecology, making it possible to track the individual movements of a wide variety of organisms, including the smallest. However, monitoring systems such as RFID tags may negatively impact an organism’s life history, with potential consequences on the reliability of data and conclusions. This study explored the potential of passive RFID tags to track the movements of three small ground-dwelling beetle species, a predator (Poecilus sericeus, Carabidae), a detritivore (Asida sericea, Tenebrionidae) and a granivore (Acinopus picipes, Carabidae), in a Mediterranean dry grassland degraded by years of cultivation. First, we tested whether carrying tags might impact individuals’ behaviour, using a before-and-after design under laboratory conditions. Despite a trend toward shorter displacements, we found no significant short-term effect of the tags on individuals’ movements. Second, we tracked a total of 25 tagged beetles in their natural environment every 4 h for 48 h. We highlight the principal limitation of using passive tags with small terrestrial beetles: the antenna has to pass over the tags to detect them, which restricts tracking to a few consecutive days after which the probability of locating an individual is low. However, the data obtained sheds light on the biological rhythms and daily movement capabilities of our target species: A. sericea is more mobile and P. sericeus less mobile than expected. Such knowledge could help predict the species’ ability to recolonise degraded areas, enabling appropriate restoration actions to be designed based on landscape ecology principles.
1. Pitfall traps are frequently used to capture ground-dwelling arthropods, particularly beetles, ants and spiders. The capture efficiency of a pitfall trapping system strongly depends on the number and opening size of traps, how traps are distributed over the sampling area (spatial arrangement) and the movement characteristics of arthropods.
2. We use numerical simulations for a single species to analyse the trap count patterns that emerge from these variables. Arthropod movement of individuals is modelled as correlated random walks, with multiple traps placed over an area, and catches are simulated as individual interaction with traps. We consider four different types of spatial arrangements of traps across a homogeneous landscape: grid (i.e. rectangular array), transect, nested-cross and randomised. We contextualise our results by considering the locomotion of Pterostichus melanarius, a highly active carabid beetle often serving as a biocontrol agent for the suppression of pest insects and weeds.
3. By simulating the trapping of randomly moving ground-dwelling arthropods, we show that there is an optimal inter-trap separation distance (trap spacing) that maximises captures, that can be expressed using exact formulae in terms of trap opening sizes, sampling area and trap number. Moreover, for the grid and nested-cross arrangements, larger trap spacing to maximise spatial coverage over the whole sampling area is suboptimal. Also, we find that over a large sampling area, there is a hierarchical order for spatial arrangements in relation to capture efficiency: grid, randomised, transect, followed by the nested-cross. However, over smaller sampling areas, this order is changed as the rate at which trap counts accumulate with trap number varies across arrangements—eventually saturating at different levels. In terms of movement effects, capture efficiency is maximised over a narrow diffusive range and does not depend strongly on the type of spatial arrangement—indicating an approximate optimal mode of arthropod activity, i.e. rate of spread.
4. Our approach simultaneously considers several important experimental design aspects of pitfall trapping providing a basis to optimise and adapt sampling protocols to other types of traps to better reflect their various purposes, such as monitoring, conservation or pest management.
Saproksilne vrste žuželk so zaradi intenzivnih gozdarskih praks vse bolj ogrožene.
Bukov kozliček (Morimus funereus), kot varstveno pomembna in karizmatična
neleteča saproksilna vrsta hrošča, predstavlja dober modelni organizem za
preučevanje disperzije slabo mobilnih saproksilnih vrst. Prav tako je za učinkovito
varovanje njega in njegovega habitata, od katerega so odvisne tudi številne druge
saproksilne vrste, potrebno podrobno poznavanje biologije vrste. Z metodo sledenja
z radijskimi oddajniki smo želeli ugotoviti disperzijske zmožnosti bukovega
kozlička, vpliv temperature in relativne vlažnosti zraka na njegovo aktivnost in
preference do hranilnih rastlin. Bukov kozliček je pokazal nižjo disperzijsko
zmožnost od letečih saproksilnih vrst, zato je pomembno, da za namene ohranjanja
vrste varujemo večje sklenjene gozdove. Pri nizkih temperaturah je bila mobilnost
osebkov izrazito nizka, pri višjih temperaturah pa so bile samice bolj mobilne od
samcev. Osebki so se zbirali na in v bližini sveže posekanega lesa, zato je metoda
monitoringa bukovega kozlička s štetjem in lovom osebkov na enotah svežega lesa
bolj primerna od metode štetja osebkov vzdolž transekta. Skladovnice hlodovine
populacijam bukovega kozlička predstavljajo pomembno potencialno grožnjo.
Osebki so se najpogosteje zbirali na svežem lesu jelke (Abies alba), ki je bila na
območju tudi najbolj razpoložljiva. Pri prehranjevanju so pokazali preferenco do
listavcev. Bukov kozliček je bil z metodo spremljanja z radijskimi oddajniki
preučevan prvič.
Saproxylic species of insects are increasingly threatened by intensive forestry
practices. Longhorn beetle Morimus funereus is a charismatic flightless saproxylic
beetle of conservation importance and as such represents a good model species for
studying the dispersion of poorly mobile saproxylic species. Detailed knowledge of
the species biology is crucial for the purposes of protecting M. funereus, as well as
its habitat and other species that inhabit it. Beetles were tracked with radio
transmitters in order to determine the dispersal capabilities of the species, effects of
air temperature and relative air humidity on its activity and its preference for host
plants. Compared to flying saproxylic species, M. funereus has shown low dispersal
capabilities, therefore conservation of large forests is needed for its protection. The
mobility of M. funereus was markedly low at low temperatures, whereas at higher
temperatures females were more mobile than males. Specimens accumulated on and
near freshly cut wood, therefore the method of counting and trapping specimens on
units of dead wood is a more appropriate for population monitoring than transect
counts. Timber piles represent an important potential threat for the populations of M.
funereus. Individials were most commonly found on fresh wood of silver fir (Abies
alba), which was also the most available at the study site. For feeding, M. funereus
has shown a prefrence for deciduous species. This was the first study of M. funereus
by means of radio tracking.
Radio telemetry with very high‐frequency transmitters is a powerful tool for studying the movement patterns of animals. Although this tracking technology is widely utilized for various vertebrates, its application is limited to only a fraction of large‐bodied insect species. Among them, beetles are the most popular insect group used for radio‐tracking due to their relatively large body size, solid exoskeleton, and to some extent the well‐known ecological background of some species. Here, we review the available literature about radio telemetry applied to beetles, focusing on current methodological advantages and constraints to record their movement, as well as how this method can assist in understanding various ecological aspects of beetle life history. Regardless of the huge potential of radio‐tracking, the number of tracked beetle species is still very low, covering so far only 13 species belonging to five families that were studied almost exclusively in the Western Palearctic region. Most studies were descriptive, measuring simple trajectory parameters and examining movement behavior as a single strategy that is not triggered by any particular internal or external cues. Ecological aspects have been accessed to a lesser extent, especially in relation to the effects of abiotic factors and habitat use. There are still conceptual knowledge gaps: promising statistical approaches for movement analyses can connect movement patterns with specific habitat utilization but they are not yet used by entomologists. Moreover, knowing the movement patterns of many individuals and species can assist us to understand the composition and dynamics at the community level.
Mobility analysis is the core idea of many applications such as vehicle navigation, trajectory analysis, POI recommendation, and traffic flow analysis. These applications collect huge spatio-temporal information represented as trajectories of a moving object such as a vehicle or people using Global Positioning System enabled devices. Various techniques are evolved to process, manage and extract useful information from trajectories. Among these techniques, clustering plays an important and integral role in developing various mobility applications. Popular traditional clustering techniques such as DBSCAN, K-means, OPTICS, hierarchical clustering, and DJ-clustering are used for this purpose. However, these techniques suffer from major issues such as entrapping in local optima and being less effective in varying densities. Further, these methods have low search capability in search space, work upon single criteria optimization, and are less scalable for the big dataset. To overcome these issues, a new multi-objective criterion-based evolutionary clustering termed CLUSTMOSA is proposed. It exploits the search capability of archived multi-objective simulated annealing (AMOSA) to cluster the dataset. It stabilizes the exploratory and exploitative behavior of the solution. In this paper, three clustering evaluation metrics are simultaneously exploited as objective functions of CLUSTMOSA. Also, a new segmentation method is presented using bearing measurement for trajectory data. It helps to eliminate multiple waypoints localized over the straight roads and prevents multiple cluster formations for the same segment. To investigate the performance, the proposed CLUSTMOSA, along with a new segmentation method using bearing measurement is compared with the state-of-art methods of trajectory data mining. The extensive experiments and analysis prove the superiority of our clustering model over state-of-art approaches.
