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GIS assumes an increasingly prominent role in niche modelling, particularly for those applications that either predict a species'' niche or estimate the environmental factors that determine a species'' distribution. The use of GIS to model population-level distributions has received considerably less attention. We developed a Monte Carlo method designed to test for statistical associations between population distribution and different types of spatial data. This method examines the spatial distribution between species presence points and distance to key vegetation, comparing the association for the observed data to that of a random data set. Poison frogs (genus Dendrobates) display a diverse array of complex parental care strategies, which are linked by an elaborate network of interactions between ecological and social factors. Territorial species vary significantly in their associated reproductive strategies, reproductive resources and size. Species with higher levels of cooperation in parental care have been hypothesized to be more strongly territorial. Here we investigate differences in spatial use patterns between two species of poison frogs, D. imitator and D. variabilis, that differ in parental care type (uniparental male care versus biparental care, respectively). We predicted that: (1) D. imitator would be more closely associated with phytotelmata than would D. variabilis; (2) home ranges of D. imitator pairs would be more inclusive and overlap more than those of D. variabilis pairs; (3) D. imitator pairs would maintain smaller home ranges than D. variabilis pairs; (4) D. imitator pairs would maintain spatially exclusive home ranges. Our results strongly support the prediction that differences in parental care of these two species are reflected in their spatial habitat use, particularly with regard to pool fidelity, territoriality, and home range size and overlap. [Copyright &y& Elsevier]

Primate home range sizes can vary tremendously as a consequence of the analytical technique chosen to estimate home range. This is exemplified by a recent dataset on free ranging snub-nosed monkeys ( Rhinopithecus bieti) in Northwest Yunnan, China. Our findings show that the grid cell method cannot substitute for the minimum convex polygon (MCP) method and vice versa. MCP-based estimates are far too large, especially when the form of the home range is irregular due to forays into peripheral areas. Here, we propose an adjusted polygon method, whereby unsuitable and never visited areas are clipped out from the polygon, thus producing more accurate results. Compared to the grid cell method, the adjusted MCP is much more robust when the number of group relocations is limited; MCP turned out to be the method of choice for calculation of monthly and seasonal home ranges. The grid cell method on the other hand yielded the most precise estimates for total or annual home ranges. The style of ranging exhibited by a given primate taxon or population determines which analytical procedures should be applied to estimate home range size, and we would stress the need for thorough evaluation of the pros and cons of home range estimators before conducting field work and analysing data. [ABSTRACT FROM AUTHOR]

The article presents a study that examined the specific characteristics of maternity roost used by female big-free tailed bats Nyctinomops (N.) macrotis in Northern Arizona and their use of water sources and foraging areas. The study areas where the bats have been captured included Arizona's Canyon de Chelly National Monument, House Rock Valley and Grand Canyon National Park and North Kaibab Ranger District. The study recorded nine successive locations for one N. macrotis during four nights, caculated the average distance traveled by the bats between successive locations and determined their flight speed. The study found that the bats' maternity roots were difficult to access and within protected areas, while their foraging areas are under the management of public or private agencies.

Home-range estimators are commonly tested with simulated animal locational data in the laboratory before the estimators are used in practice. Although kernel density estimation (KDE) has performed well as a home-range estimator for simulated data, several recent studies have reported its poor performance when used with data collected in the field. This difference may be because KDE and other home-range estimators are generally tested with simulated point locations that follow known statistical distributions, such as bivariate normal mixtures, which may not represent well the space-use patterns of all wildlife species. We used simulated animal locational data of 5 point pattern shapes that represent a range of wildlife utilization distributions to test 4 methods of home-range estimation: 1) KDE with reference bandwidths, 2) KDE with least-squares cross-validation, 3) KDE with plug-in bandwidths, and 4) minimum convex polygon (MCP). For the point patterns we simulated, MCP tended to produce more accurate area estimates than KDE methods. However, MCP estimates were markedly unstable, with bias varying widely with both sample size and point pattern shape. The KDE methods performed best for concave distributions, which are similar to bivariate normal mixtures, but still overestimated home ranges by about 40-50% even in the best cases. For convex, linear, perforated, and disjoint point patterns, KDE methods overestimated home-range sizes by 50-300%, depending on sample size and method of bandwidth selection. These results indicate that KDE does not produce home-range estimates that are as accurate as the literature suggests, and we recommend exploring other techniques of home-range estimation. [ABSTRACT FROM AUTHOR]

With group sizes sometimes >300 individuals, the Angolan black-and-white colobus (Colobus angolensis ruwenzorii) population in Nyungwe Forest, Rwanda is an intriguing exception to the tendency for folivores to live in smaller groups than expected relative to body size. Researchers have hypothesized that the unusually high quality of foliage at Nyungwe allows colobus there to avoid intragroup feeding competition, releasing constraints on the formation of large groups (Fimbel et al., ). We collected data on the activity and ranging patterns of a >300-member Nyungwe colobus group and compared our results to those from smaller groups in other black-and-white colobus (Colobus spp.) populations. Colobus at Nyungwe spent far more time feeding and moving (62%) and far less time resting (32%) than black-and-white colobus at any other site. The annual home range of the Nyungwe colobus was also many times larger (95% minimum convex polygon: 20.7 km 2 ; 95% fixed kernel: 24.4 km 2 ) than those for other populations. We terminated our research after the group engaged in an unprecedented migration among black-and-white colobus by moving 13 km south of their former range. Our results suggest that intragroup scramble competition may be more intense than originally believed within the large colobus groups at Nyungwe and that long periods of resource renewal may be necessary after a large colobus group passes through an area, thereby potentially helping to explain their wide ranging patterns. We discuss the socioecological convergence between the Nyungwe colobus and Chinese snub-nosed monkeys (Rhinopithecus spp.) and suggest directions for future research on the unique black-and-white colobus population at Nyungwe. [ABSTRACT FROM AUTHOR]

The manner in which space is utilized by animals is influenced by several factors, including habitat quality and the distribution and abundance of resources. We used 4 years (2000-2003) of radiotelemetry data to investigate the space-use pattern of female Florida black bears (Ursus americanus floridanus) in the Ocala National Forest and an adjacent residential community of Lynne, north-central Florida. Annual home-range size (95% fixed kernel density estimator) ranged from 3.8 km² to 126.9 km², and averaged (± SE) 24.2 ± 3.55 km². Home ranges were largest during 2000 when a drought led to a forest-wide mast failure, suggesting that abundance of food resources can substantially influence space-use pattern. Home-range sizes during autumn (19.92 ± 4.59 km²) were substantially larger than during summer (8.26 ± 0.99 km²). Although annual home-range size did not differ between the 2 study sites, home ranges in summer were smaller in Lynne (5.30 ± 1.01 km²) than in Ocala National Forest (9.82 ± 1.29 km²), whereas home ranges in autumn were twice as large in Lynne (35.76 ± 13.91 km²) as in Ocala National Forest (13.24 ± 1.80 km²). We suggest that site-specific differences in the size of seasonal home range are due to differences in habitat characteristics and the degree of habitat fragmentation between the 2 study sites. [ABSTRACT FROM AUTHOR]

In the Thabazimbi district, conflict and confusion have existed surrounding the status and behaviour of cheetahs (Acinonyx jubatus) on wildlife ranches. A study of these cheetahs was undertaken to understand the ranging behaviour of cheetahs outside conservation areas. Five cheetahs were caught using double-door capture cages and fitted with radio collars; a coalition of two males, two out of a coalition of three males and a lone male. The coalition of two was tracked for 17 months, the three were tracked for eight months and the lone male's radio collar failed days after being released. For the coalition of two the 100% minimum convex polygon (MCP) method produced a range size of 310 km² and the 100% MCP for the coalition of three was 190 km², neither of these ranges were asymptotic. [ABSTRACT FROM AUTHOR]

Abstract: I undertook a behavioral study to determine red-cockaded woodpecker (Picoides borealis) home-range size at the Savannah River Site, South Carolina, USA. In this location, because much of the timber was harvested in the late 1940s and early 1950s, the available habitat largely consisted of younger trees (e.g., less than 45 years old), not generally considered prime habitat for this species. From 1992 to 1995, I observed seven groups of red-cockaded woodpeckers to determine year-round home-range size. Most of the previous home-range studies on this species used the minimum convex polygon approach to estimate the size of the home range. I compared the minimum convex polygon and fixed kernel home-range estimation methods for each group. I found that the fixed kernel method gave consistently smaller estimates of home range than did the minimum convex polygon, a result directly related to the methodologies of the techniques. Mean home-range sizes for the 95% level were 56.9±5.2S.E.ha with the fixed kernel versus 91.9±11.7S.E.ha with the minimum convex polygon. Core area (50%) means were 4.5±0.5S.E.ha for the fixed kernel versus 16.7±2.4S.E.ha with the minimum convex polygon. It is recommended that future home-range studies use the fixed kernel estimator rather than the minimum convex polygon as it gives a more realistic and appropriate depiction of the area actually used by the birds within a given group. In estimating the number of groups that may be accommodated in a particular area, the mean home-range size as well as its shape need to be considered. Home-range size estimates at the Savannah River Site were similar to those obtained elsewhere in the species’ range. Red-cockaded woodpeckers, in spite of the prevalence of relatively young forest structure, did not increase their home-range size to compensate for the paucity of older, more mature pine habitat. [Copyright &y& Elsevier]

Resource availability and reproductive activity can exert contrasting demands on movements of promiscuous or polygynous mammals. Movements of the black-eared opossum (Didelphis aurita) vary seasonally in the Atlantic Rainforest of Brazil, so our objectives were to test the relative importance of reproductive activity and resource abundance on movement areas and intensity of use by opossums. We used a spool-and-line device to map the path of individuals, to estimate daily movement areas, and to measure intensity of habitat use. Two models were compared by generalized linear models, by grouping movements by reproductive or climatic season. Males used larger areas less intensively in the breeding season, whereas the movement of females did not differ between breeding and nonbreeding season. Differences between movements of females were significant only when grouped by climatic seasons, with females using larger areas less intensively in the dry season. Movements of females were determined by resource availability, whereas movements of males were determined by reproductive season. [ABSTRACT FROM AUTHOR]

Because the spatial arrangements of nocturnal prosimians are often used to indicate their social systems, it is important to assess the reliability of methods used to analyze ranging patterns. We compared methods of home range analysis for 2 species of nocturnal prosimians: central pottos (Perodicticus potto edwardsi) and Cross River Allen’s galagos ({Sciurocheirus cameronensis}). We conducted radio-tracking studies of 10 pottos and 8 galagos from October 1999 - November 2000 in the montane rain forests of southwest Cameroon. We calculated home ranges via minimum convex polygon (MCPs) and kernel analyses. Adult potto home ranges averaged 145.2 ha (MCPs) versus only 28.4 ha via kernel analysis; the difference is statistically significant. The mean home range of galagos is 18.3 ha via MCPs and 2.19 ha via kernel analysis; the difference is statistically significant. Neither MCP nor kernel analyses revealed a sex difference in adult home ranges for pottos and galagos. Kernel analysis gave more reliable estimates of home ranges than the minimum convex polygon method used in many studies of nocturnal prosimians. Minimum convex polygon analysis tended to overestimate the range sizes and to include many areas not traversed by the animal. We compared our findings with those from an earlier study of similar species in Gabon, where little attention was given to the home range analysis, technique. Together with studies of lemur spatial systems they highlight the importance of considering the method of home range analysis when it is to be applied to understanding social systems. [ABSTRACT FROM AUTHOR]

A lack of quantitative information on life history of the western gray squirrel (Sciurus griseus) has hampered conservation and management efforts across its range. We report on data from 21 squirrels radiotracked in Klickitat County, Washington, from 1998 to 1999 to examine the interaction between home-range size, sex, and season. Home-range estimates were calculated by using minimum convex polygon and fixed kernel methods. Only adult animals with ≥40 relocations were included in total home-range comparisons. Estimates of 95% minimum convex polygon home range in Washington averaged 73.0 ha for males (n = 9) and 21.6 ha for females (n = 12) for year-round use, significantly larger than those from Oregon and California. Differences in homerange size of males and females were significant. Fixed kernel and minimum convex polygon estimates were similar in size. We suggest that near the northern limit of the species' geographic range low species richness, low abundance, and a patchy distribution of mast-producing vegetation result in large male and female home ranges, low overlap of female home ranges, and a sparsely distributed squirrel population. [ABSTRACT FROM AUTHOR]

The degree of space-use overlap among adjacent individuals is a central focus of many wildlife investigations. We studied the comparability of minimum convex polygon and fixed-kernel home-range overlap indices and Volume of Intersection (VI) scores using simulated data. We simulated pairs of point patterns to represent telemetry locations of adjacent individuals and varied the amount of potential overlap in the simulation region (100%, 50%, and 10%) and the point distribution (random, loosely clumped, and tightly clumped). We created 1,000 pairs of point sets (60 points in each individual set) for each of the 9 potential overlap and point distribution combinations. In all 9 treatment combinations, VI scores were highest followed by kernel and then polygon estimates. Raw differences among estimates within a treatment were greatest when there was 50% potential overlap, and overlap indices decreased as the degree of clumping increased. The relative differences among overlap indices within a treatment were affected most by potential overlap; differences generally were greatest at 10% and least at 100%. Correlation between index values was lowest for random point patterns, and highest for loosely clumped and tightly clumped point patterns. Although the VI tended to indicate the most overlap and minimum convex polygon the least, there was no consistent correction factor among techniques because of the interacting effects of the overlap index, distribution pattern, and potential overlap. Interpretation of overlap measures requires careful consideration of assumptions and properties of animals under study. [ABSTRACT FROM AUTHOR]

Movements, ranging behavior, and social organization of the rice field rat (Rattus argentiventer) were studied by radiotracking in a rice field in West Java, Indonesia. Home ranges were estimated by the minimum convex polygon method and were found to be significantly larger in the nonbreeding season than in the breeding season. During the breeding season, males had larger home ranges than did females (3.20-3.24 ha, as compared to 2.51-2.34 ha), but no sexual differences were found in the nonbreeding season. Overlap between home ranges occurred during the breeding season, especially for males. During the nonbreeding season, rats appeared to be nomadic, and nests seemed to be distributed at random within ranges. Males and females were never found to share nests during the nonbreeding season. Habitat use was investigated by recording percentage occupancy of the following habitat elements: rice paddies, banks, and vegetation. Totals of 63% and 60% of radiofixes were made in paddies during the rainy and dry seasons, respectively. Paddies were probably used for feeding, nest construction, and protection from predation. [ABSTRACT FROM AUTHOR]

Abstract: The manner in which space is used by animals may influence several aspects of biology, including the pattern of resource use and intra-specific competition. We monitored 16 radio-collared female black bears (Ursus americanus) for 9,216 radio days during 1993–1995 in the White River National Wildlife Refuge (WRNWR), Arkansas, U.S.A. to investigate space use patterns. Annual home ranges (95% convex polygon) ranged from 2.10 to 11.34 km2 with a mean (± SD) size of 4.90 (± 2.09) km2 (n = 16). Largest home ranges were occupied by 2 females with yearlings during one year of study. Home ranges among neighbouring bears overlapped considerably. Although bears maintained larger home ranges during summer, the size of home range did not differ among seasons (P > 0.50). Our estimates of home range size for female black bears were smaller than those obtained in a study of the same population during 1979–1982. Because the size of the bear population at WRNWR was substantially smaller (about 130 bears) during 1979–1982 compared to the present population of ?348 bears, these results suggested that population density and size of female black bear home ranges may be negatively correlated. Conservation implications of density-dependent space use pattern are also discussed. [Copyright &y& Elsevier]

Summary 1.Long-tailed tits Aegithalos caudatus L. are cooperative breeders in which breeders that have failed in their own breeding attempt become helpers at the nest of relatives. We investigated the effects of kinship on the spatial dynamics of non-breeding flocks of long-tailed tits in order to determine the information available on the kinship of other members of the population from their use of home ranges. 2.A novel method of home range analysis was devised based on ‘convex hull peeling’. This method takes into account the dispersion of all fixes within a home range and permits the quantitative analysis of home range use. In addition, the method allows the extent of overlap between adjacent home ranges to be determined and the use of those areas to be investigated. 3.Non-breeding flocks of long-tailed tits were composed mainly of relatives, but also included unrelated immigrants. Flock ranges were large and there was extensive overlap between adjacent flocks. 4.The degree of range overlap was significantly affected by the relatedness of flocks. If two flocks contained close relatives they were more likely to overlap than two flocks containing non-relatives. Moreover, the amount of overlap was significantly greater for two adjacent related flocks than for two adjacent unrelated flocks. 5.The use of overlapping areas of non-breeding ranges of long-tailed tit flocks was also influenced significantly by relatedness. Overlapping flocks that were unrelated to each other usually avoided areas of overlap, while related flocks did not generally show such avoidance behaviour. 6.Kinship has significant effects on the spatial dynamics of non-breeding flocks of long-tailed tits and therefore flock behaviour can provide information on the relatedness of other members of the population that might be important for helping decisions in this cooperatively breeding species. [ABSTRACT FROM AUTHOR]

Abstract There is a paucity of data on the movement patterns of feral cats in Australia. Such data can be used to refine control strategies and improve track-based methods of monitoring populations of feral cats. In this study the home ranges and movements of male feral cats were examined over 3.5 years in a semiarid woodland environment in central Australia. Two home range estimators were used in the examination: (i) minimum convex polygon (MCP); and (ii) fixed kernel. The most widely used method of estimating home range in feral cats is MCP, while the fixed kernel method can be used to identify core areas within a home range. On the basis of the MCP method, the long-term home ranges of feral cats in central Australia were much larger than those recorded elsewhere (mean, 2210.5 ha). Twenty-four hour home ranges were much smaller (mean, 249.7 ha) and feral cats periodically shifted their 24 h ranges within the bounds of their long-term home ranges. Core area analysis indicated marked heterogeneity of space use by male feral cats. Several instances where feral cats moved large distances (up to 34 km) were recorded. These long distance movements may have been caused by nutritional stress. Using data from the literature, it is shown that prey availability is a primary determinant of long-term home range size in feral cats. The relevance of the results to the design of management strategies for feral cats in central Australia is also discussed. [ABSTRACT FROM AUTHOR]

Patterns of home range overlap between individuals are key parameters used in discussions of sociality in nocturnal prosimians. Despite the importance of space use variables in defining social structure in nocturnal prosimians, researchers have yet to reach a consensus concerning the most reliable techniques for measuring patterns of home range use. In this paper, we review the methods used in 27 studies of nocturnal prosimian ranging behavior published since 1977. We discuss the usefulness and limitations of the various methods of data collection (radio tracking, trap mark, and identification of sleeping site locations) and data analysis (minimum convex polygon method, minimum concave polygon method, and quadrat analysis) used in these studies. We conclude that the most effective method for gathering data on individual movements and social interactions is direct observation of individual radio tagged animals during all-night follows. In those cases where radio tracking and/or all-night follows are not possible, trap mark techniques can be used, although they tend to greatly underestimate home range size. We recommend that data collected on nocturnal prosimian ranging behavior be analyzed using the minimum convex polygon method, quadrat analysis, and, perhaps, one other of the more mathematically sophisticated techniques popular in studies of non-primate mammals. Finally, we urge researchers to employ standardized methods of data collection and data analysis in future studies of range use in nocturnal prosimians. Without standardization of methods, quantitative comparisons of the findings from different studies are biologically meaningless and prevent cross-species comparisons of space use and its relation to sociality. Am. J. Primatol. 51:3–19, 2000. © 2000 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

• Isotopic niche reflects stable carbon and nitrogen isotopes in animals' tissues. • Celebrated indicators for niche description often rely on Gaussian assumptions. • We advocate minimum convex polygons (MCP) for isotopic niche assessment. • The method allows for outlier rejection and relaxes Gaussian assumption. • A R code allows for illustration on real data. Ecological (isotopic) niche refers to a surface in a two-dimensional space, where the axes correspond to environmental variables that reflect values of stable isotopes incorporated in an animal's tissues. Carbon and nitrogen stable isotope ratios (δ13C-δ15N) notably provide precious information about trophic ecology, resource and habitat use, and population dynamics. Various metrics allow for isotopic niche size and overlap assessment. In this paper, we advocate α-minimum convex polygons (MCP) - that have long been used for home range estimation – as a relevant tool for isotopic niche size, overlap, and characteristics. The method allows for outlier rejection while being suited to data that are not Gaussian in the bivariate isotopic (δ13C-δ15N) space. The proposed indicators are compared to other existing approaches and are shown to be complementary. Notably an indicator of divergence within the niche is introduced, and allows for comparisons at low (n > 6) and different sample sizes. The R code is made publicly available and will enable ecologists to perform isotopic niche comparison, contraction and expansion assessment, and overlap, based on various methods. [ABSTRACT FROM AUTHOR]

This study aims to clarify the impact of the COVID-19 pandemic on home range. The home range is the area that individuals traverse in conducting their daily activities, such as working and shopping. In Japan, the central government declared the first state of emergency in April 2020. This study analyzed the panel data for mobile phone GPS location history from April 2019 to April 2020 in Ibaraki City, Osaka Metropolitan area. The study applied the minimum convex polygon method to analyze the data. The results show that the home range decreased significantly between April 2019 and April 2020. Specifically, the home range in 2020 decreased to approximately 50% of that in 2019 because of COVID-19 infection control measures, preventing people from traveling far from their homes and only allowing them to step outside for the bare minimum of daily activities and necessities. The results suggest that the emergency reduced people's home ranges to the neighborhood scale. Therefore, it is necessary to consider designing new walkable neighborhood environments after the COVID-19 pandemic era. [ABSTRACT FROM AUTHOR]

• Range size estimates are highly correlated across data types and approaches. • Taxonomy does not bias range size estimates. • Ranked range sizes varied most for species with intermediate range sizes. • The rarest fishes are consistently identified across data types and approaches. • Open access biodiversity data is valuable in assessments of geographic rarity. Geographic rarity is a driver of a species' intrinsic risk of extinction. It encompasses multiple key components including range size, which is one of the most commonly measured estimates of geographic rarity. Range size estimates are often used to prioritize conservation efforts when there are multiple candidate species, because data for other components of rarity such as population size are sparse, or do not exist for species of interest. Range size estimates can provide rankings of species vulnerability to changing environments or threats, identifying rare species for future study or conservation initiatives. However, range sizes can be estimated by several different metrics, and the degree of overlap in the identification of the rarest or most common species across methodologies is not well understood. This knowledge gap compromises our ability to prioritize correctly rare species, and presents a particularly difficult challenge for stream-dwelling organisms with distributions constrained to river networks. We evaluated the relationship of multiple range size estimates of a subset of freshwater fishes native to the United States to determine the degree of overlap in rarity rankings using different data sources and grain sizes. We used publicly available, open access data from the Global Biodiversity Information Facility (GBIF) to calculate extent of occurrence (minimum convex polygons) and area of occupancy (total area occupied, measured across various grain sizes). We compared range sizes estimated using GBIF data with the best available estimates of current distributions described by publicly available digital maps (NatureServe) to evaluate the efficacy of GBIF data in assessments of range size. We found strong correlations between range size estimates across analytical approaches and data sources with no detectable bias of taxonomy. We found that variation among rarity rankings was highest for species with intermediate range sizes indicating that the approaches considered here generally converge when used to identify the rarest or the most common species. Importantly, our results show that the rarest, and perhaps the most vulnerable, species are consistently identified across common methodological approaches. More broadly, our results support the use of open access biodiversity data that include opportunistically collated and collected point occurrence records as a complement to coarse-grain (e.g., whole range map) approaches, as we observed no systematic bias or deviation across data sources in our analyses. This indicates databases such as the GBIF may help fill important fundamental and applied knowledge gaps for many poorly understood species, particularly in a broad-scale, multispecies framework. [ABSTRACT FROM AUTHOR]

Madagascar's dramatic climatic fluctuations mean most lemurs adjust behaviors seasonally as resource availability fluctuates. Many lemurs will adopt one of two strategies, a resource maximizer or an area minimizer, when adjusting to seasonal shifts in resource availability. However, it is unknown if and how aye-aye (Daubentonia madagascariensis) ranging behavior is influenced by seasonality. We explored whether habitat use changed seasonally. We followed two aye-ayes, an adult male and an adult female, in the undisturbed forest of Torotorofotsy, Madagascar, from April 2012 to December 2017. We used instantaneous focal-animal sampling to collect behavioral data every 5 min and GPS locations every 20 min. We used the minimum convex polygon (MCP) to determine overall home range, and the Brownian bridge movement model (BBMM) to estimate overall and seasonal home range of the female aye-aye from November 2014 to October 2017. We used Wilcoxon signed-rank tests to determine whether there were significant differences in home range sizes between seasons across years and to examine whether there were seasonal differences in height of invertebrate foraging, generalized linear models to assess seasonal differences in travel rates and nesting locations, and χ2 tests to determine whether there were differences in forest strata use when foraging on invertebrates. The male's MCP home range was 2,586 ha, and the female's MCP home range was 765 ha. The seasonal BBMM for the female varied between 443.6 and 1,010.0 ha, though infant rearing appears to have influenced these values. There were no significant differences in seasonal home range, travel rates, nesting locations, or height of invertebrate feeding. However, canopy level invertebrate foraging occurred more often than understory or ground levels. It appears aye-ayes in this undisturbed forest were not influenced by seasonal shifts and had larger home ranges than any previously reported. These findings may indicate that aye-ayes in an undisturbed forest are resource maximizers, closely linked to invertebrate assemblages., (© 2020 S. Karger AG, Basel.)

Home range estimation is routine practice in ecological research. While advances in animal tracking technology have increased our capacity to collect data to support home range analysis, these same advances have also resulted in increasingly autocorrelated data. Consequently, the question of which home range estimator to use on modern, highly autocorrelated tracking data remains open. This question is particularly relevant given that most estimators assume independently sampled data. Here, we provide a comprehensive evaluation of the effects of autocorrelation on home range estimation. We base our study on an extensive data set of GPS locations from 369 individuals representing 27 species distributed across five continents. We first assemble a broad array of home range estimators, including Kernel Density Estimation (KDE) with four bandwidth optimizers (Gaussian reference function, autocorrelated‐Gaussian reference function [AKDE], Silverman's rule of thumb, and least squares cross‐validation), Minimum Convex Polygon, and Local Convex Hull methods. Notably, all of these estimators except AKDE assume independent and identically distributed (IID) data. We then employ half‐sample cross‐validation to objectively quantify estimator performance, and the recently introduced effective sample size for home range area estimation (N^area) to quantify the information content of each data set. We found that AKDE 95% area estimates were larger than conventional IID‐based estimates by a mean factor of 2. The median number of cross‐validated locations included in the hold‐out sets by AKDE 95% (or 50%) estimates was 95.3% (or 50.1%), confirming the larger AKDE ranges were appropriately selective at the specified quantile. Conversely, conventional estimates exhibited negative bias that increased with decreasing N^area. To contextualize our empirical results, we performed a detailed simulation study to tease apart how sampling frequency, sampling duration, and the focal animal's movement conspire to affect range estimates. Paralleling our empirical results, the simulation study demonstrated that AKDE was generally more accurate than conventional methods, particularly for small N^area. While 72% of the 369 empirical data sets had >1,000 total observations, only 4% had an N^area >1,000, where 30% had an N^area <30. In this frequently encountered scenario of small N^area, AKDE was the only estimator capable of producing an accurate home range estimate on autocorrelated data. [ABSTRACT FROM AUTHOR]

Quantifying animals' home ranges is a key problem in ecology and has important conservation and wildlife management applications. Kernel density estimation (KDE) is a workhorse technique for range delineation problems that is both statistically efficient and nonparametric. KDE assumes that the data are independent and identically distributed (IID). However, animal tracking data, which are routinely used as inputs to KDEs, are inherently autocorrelated and violate this key assumption. As we demonstrate, using realistically autocorrelated data in conventional KDEs results in grossly underestimated home ranges. We further show that the performance of conventional KDEs actually degrades as data quality improves, because autocorrelation strength increases as movement paths become more finely resolved. To remedy these flaws with the traditional KDE method, we derive an autocorrelated KDE (AKDE) from first principles to use autocorrelated data, making it perfectly suited for movement data sets. We illustrate the vastly improved performance of AKDE using analytical arguments, relocation data from Mongolian gazelles, and simulations based upon the gazelle's observed movement process. By yielding better minimum area estimates for threatened wildlife populations, we believe that future widespread use of AKDE will have significant impact on ecology and conservation biology. [ABSTRACT FROM AUTHOR]

ABSTRACT The rare Amazonian snake Eutrachelophis papilio is known from only five individuals, from four localities, belonging to its type-series, the more recent collected over 10 years ago. Here, we expand its distribution and describe its color in life for the first time. We also provide an estimate of its distribution area using the minimum convex polygon method and identify the values of anthropic pressure within its known distribution range with the Human Footprint Index. The new occurrence is located 291 km from the nearest known locality and its distribution is associated with pristine forests. Considering its rarity, and the absence of demographic and biological data, we suggest that the species should be classified as Data Deficient by IUCN criteria.