Home Range Overlap Research Articles

Pair formation, home range, and spatial variation in density, size and social status in blotched foxface Siganus unimaculatus on an Okinawan coral reef.

The present study examined pair formation, spatial pattern of home range and spatial variation in density, size and social status of blotched foxface Siganus unimaculatus (family Siganidae) on an Okinawan coral reef. Of 32 pairs sampled for sexing, 31 (96.9%) were heterosexual and showed size-assortative pairing. Developed ovaries were found in April and July, whereas oocytes were immature in August, September and February. Heterosexual pairing was found in both reproductive and non-reproductive periods. Home range size tended to be positively related to fork length (FL). The degree of home range overlap for same size class pairs was smaller than that for different size class pairs. The intraspecific behavior when two pairs approached each other was categorized as ‘attack,’ ‘agonistic display’ and ‘no interactions,’ and the frequency of agonistic behaviors (“attack” or “agonistic display”) was significantly greater than “no interactions.” Underwater observations at a seagrass bed, a rocky reef flat and a sheltered reef slope revealed that the mean FL was significantly smaller at the sheltered reef slope (4–13 cm) than at the rocky reef flat (>13 cm). No individuals were found in the seagrass bed. Most individuals less than 6 cm FL were solitary, whereas most individuals over 7 cm FL were paired. Density was significantly greater on the sheltered reef slope than on the rocky reef flat.

Short-Term Space-Use Patterns of Translocated Mojave Desert Tortoise in Southern California.

Increasingly, renewable energy comprises a larger share of global energy production. Across the western United States, public lands are being developed to support renewable energy production. Where there are conflicts with threatened or endangered species, translocation can be used in an attempt to mitigate negative effects. For the threatened Mojave desert tortoise (Gopherus agassizii), we sought to compare habitat- and space-use patterns between short-distance translocated, resident, and control groups. We tested for differences in home range size based on utilization distributions and used linear mixed-effects models to compare space-use intensity, while controlling for demographic and environmental variables. In addition, we examined mean movement distances as well as home range overlap between years and for male and female tortoises in each study group. During the first active season post-translocation, home range size was greater and space-use intensity was lower for translocated tortoises than resident and control groups. These patterns were not present in the second season. In both years, there was no difference in home range size or space-use intensity between control and resident groups. Translocation typically resulted in one active season of questing followed by a second active season characterized by space-use patterns that were indistinguishable from control tortoises. Across both years, the number of times a tortoise was found in a burrow was positively related to greater space-use intensity. Minimizing the time required for translocated tortoises to exhibit patterns similar to non-translocated individuals may have strong implications for conservation by reducing exposure to adverse environmental conditions and predation. With ongoing development, our results can be used to guide future efforts aimed at understanding how translocation strategies influence patterns of animal space use.

Home range of Aspidoscelis cozumela (Squamata: Teiidae): a parthenogenetic lizard microendemic to Cozumel Island, México

Home range is defined as the area within which an individual moves to acquire resources necessary to increase their fitness and may vary inter and intra-specifically with biotic and abiotic factors. This study details the home range of the parthenogenic lizard, Aspidoscelis cozumela, an active forager microendemic to Cozumel Island, México, with high preference for open sand beaches. The home range of A. cozumela was compared with other species of Aspidoscelis (gonochoric and parthenogenetic) and other lizards that occupy coastal habitats. Furthermore, the biotic and abiotic factors that may influence home range were analyzed. This study was conducted in the beach located on the East side of the island (area of 4,000 M2) that is composed primarily of halophyte vegetation with high levels of sunlight. From 1999 to 2001, nine samples were taken which included the dry, rainy, "nortes", and breeding seasons. During each sampling, capture-mark-recapture techniques were conducted and the date, time of day, and snout-vent length (SVL) were recorded to the nearest millimeter. Individuals were located in the study area using a bi-coordinate reference using 10 x 10 m subdivisions of the habitat. Home range and home range overlap were calculated using the convex polygon method in McPaal and home range/SVL correlation was tested using Pearson's correlation. To calculate females home range, three or more recaptures were considered. A total of 20 home ranges that averaged 45.1 ± 14.0 m2 were obtained and no correlation between SVL and home range size was detected (p = 0.9229, n = 20). However, removing individuals with outlier home ranges (females with home ranges > 100 m2, n = 2) resulted in a positive correlation with SVL (r = 0.61, p = 0.0072, n = 18). A 22.9 ± 5.7% overlap in home range was also detected. The small home range of A. cozumela represents the smallest home range within the Aspidoscelis genus recorded to date (including both parthenogenetic and gonochoric species) and contrasts the theoretical predictions of broad home ranges for widely foraging species. Thermoregulatory benefits and a high population density may explain the small home range of A. cozumela. Although this species is highly adapted to the environmental conditions present on the open sand beaches, anthropogenic effects on these habitats by the development of tourism infrastructure may jeopardize their existence on Cozumel Island.

Overlapping home ranges and microhabitat partitioning among Canyon Wrens (Catherpes mexicanus) and Rock Wrens (Salpinctes obsoletus)

ABSTRACT Patterns of animal space use may vary according to species identity, presence of conspecifics, presence of heterospecifics, and resource availability. We evaluated joint space use by Canyon Wrens (Catherpes mexicanus) and Rock Wrens (Salpinctes obsoletus) by comparing home range sizes, home range overlap, and foraging behavior. Canyon and Rock wrens are ecologically similar species which frequently co-occur along rocky cliffs where members of both species feed on terrestrial invertebrates. Interactions between Canyon and Rock wrens provide information about avian space use and foraging strategies in understudied cliff habitats. We estimated home range for each species using ArcGIS, and quantified foraging microhabitat use. Canyon Wren home ranges were widely spaced, did not overlap conspecifics, and were significantly larger than those of Rock Wrens. Rock Wrens occurred at higher densities and home ranges overlapped conspecifics in 33% of cases by an average of 19%. Canyon and Rock wren home rang...

Evaluating distributional shifts in home range estimates.

A variety of methods are commonly used to quantify animal home ranges using location data acquired with telemetry. High-volume location data from global positioning system (GPS) technology provide researchers the opportunity to identify various intensities of use within home ranges, typically quantified through utilization distributions (UDs). However, the wide range of variability evident within UDs constructed with modern home range estimators is often overlooked or ignored during home range comparisons, and challenges may arise when summarizing distributional shifts among multiple UDs. We describe an approach to gain additional insight into home range changes by comparing UDs across isopleths and summarizing comparisons into meaningful results. To demonstrate the efficacy of this approach, we used GPS location data from 16 bighorn sheep (Ovis canadensis) to identify distributional changes before and after habitat alterations, and we discuss advantages in its application when comparing home range size, overlap, and joint-space use. We found a consistent increase in bighorn sheep home range size when measured across home range levels, but that home range overlap and similarity values decreased when examined at increasing core levels. Our results highlight the benefit of conducting multiscale assessments when comparing distributions, and we encourage researchers to expand comparative home range analyses to gain a more comprehensive evaluation of distributional changes and to evaluate comparisons across home range levels.

Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape.

The "landscape of fear" model has been proposed as a unifying concept in ecology, describing, in part, how animals behave and move about in their environment. The basic model predicts that as an animal's landscape changes from low to high risk of predation, prey species will alter their behavior to risk avoidance. However, studies investigating and evaluating the landscape of fear model across large spatial scales (tens to hundreds of thousands of square kilometers) in dynamic, open, aquatic systems involving apex predators and highly mobile prey are lacking. To address this knowledge gap, we investigated predator-prey relationships between. tiger sharks (Galeocerdo cuvier) and loggerhead turtles (Caretta caretta) in the North Atlantic Ocean. This included the use of satellite tracking to examine shark and turtle distributions as well as their surfacing behaviors under varying levels of home range overlap. Our findings revealed patterns that deviated from our a priori predictions based on the landscape of fear model. Specifically, turtles did not alter their surfacing behaviors to risk avoidance when overlap in shark-turtle core home range was high. However, in areas of high overlap with turtles, sharks exhibited modified surfacing behaviors that may enhance predation opportunity. We suggest that turtles may be an important factor in determining shark,distribution, whereas for turtles, other life history trade-offs may play a larger role in defining their habitat use. We propose that these findings are a result of both biotic and physically driven factors that independently or synergistically affect predator-prey interactions in this system. These results have implications for evolutionary biology, community ecology; and wildlife conservation. Further, given the difficulty in studying highly migratory marine species, our approach and conclusions may be applied to the study of other predator-prey systems.

Home-range interactions of three sympatric mesopredators in east Texas

Spatial interactions among predators are central to their behavioral ecology. Although coyotes (Canis latrans Say, 1823), bobcats (Lynx rufus (Schreber, 1777)), and raccoons (Procyon lotor (L., 1758)) occur sympatrically throughout much of the USA, little is known about the nature of inter- and intra-specific spatial interactions. We used kernel analysis to estimate home ranges and core areas for these species. We estimated home-range overlap within and among species using the utilization distribution overlap index (UDOI) and percent overlap. Bobcat and coyote home ranges were similar in extent, whereas raccoons had substantially smaller home ranges. Only bobcats displayed seasonal differences in home-range size. Male bobcats had larger home ranges than female bobcats; there was no sex-based differentiation in home range or core area for coyotes or raccoons. Home-range overlaps calculated using percent overlap were consistently larger than UDOI estimates. Percent overlap seemed to exaggerate the extent to which individuals of the same species share space. Bobcats and coyotes shared space more than raccoons did with either bobcats or coyotes, which indicates that raccoons may have avoided areas used by trophically higher ranking mesopredators or that species with similar feeding strategies had lower levels of overlap to avoid competition.

Spatial Ecology of Invasive Black Rats (Rattus rattus) On San Clemente Island, California

Black rats (Rattus rattus) are among the most ecologically destructive invasive vertebrates. On San Clemente Island (SCI) they depredate multiple endemic endangered species. Rat control has been part of the Department of the United States Navy's endangered species conservation programs on SCI since 1987, but no previous research into their ecology had been conducted. To improve understanding and management of black rats on SCI, from September 2011 to January 2012, we conducted a radiotelemetry study to estimate spatial use metrics for 20 rats. We found 95% kernel density estimates ranged from 0.14 to 6.45 ha (mean = 1.75 ha) with an average home-range size of 2.09 ha for males and 1.53 ha for females. We did not detect any effect of habitat type or time of day on spatial-use metrics. Home range overlap among sympatric individuals ranged from 3% to 73%, with 19 of 20 individuals (95%) overlapping two or more other rats wearing transmitters. Better understanding of black rat spatial ecology will allow for improved rat-control efforts to facilitate ESA-listed taxa conservation efforts on SCI.

Interactions between density, home range behaviors, and contact rates in the Channel Island fox (Urocyon littoralis).

Many of the mechanisms underlying density-dependent regulation of populations, including contest competition and disease spread, depend on contact among neighboring animals. Understanding how variation in population density influences the frequency of contact among neighboring animals is therefore an important aspect to understanding the mechanisms underlying, and ecological consequences of, density-dependent regulation. However, contact rates are difficult to measure in the field and may be influenced by density through multiple pathways. This study explored how local density affects contact rates among Channel Island foxes (Urocyon littoralis) through two pathways: changes in home range size and changes in home range overlap. We tracked 40 radio-collared foxes at four sites on San Clemente Island, California. Fox densities at the four sites ranged from 2.8 ± 1.28 to 42.8 ± 9.43 foxes/km2. Higher fox densities were correlated with smaller home ranges (R2 = 0.526, F1,38 = 42.19, P < 0.001). Thirty foxes wore collars that also contained proximity loggers, which recorded the time and duration of occasions when collared foxes were within 5 m of one another. Contact rates between neighboring fox dyads were positively correlated with home range overlap (R2 = 0.341, P = 0.008), but not fox density (R2 = 0.012, P = 0.976). Individuals at high densities had more collared neighbors with overlapping home ranges (R2 = 0.123, P = 0.026) but not an increase in the amount of contact between individual neighbors. This study was the first time contact rates were directly measured and compared to density and home range overlap. Results suggest that foxes exhibit a threshold in their degree of tolerance for neighbors, overlap is a reliable index of the amount of direct contact between island foxes, and disease transmission rates will likely scale with fox density.

How do demographic and social factors influence parent-offspring conflict? The case of wild black and gold howler monkeys (Alouatta caraya).

In this study, we examined the influence of demography and social context on mother-offspring conflict in wild black and gold howler monkeys (Alouatta caraya) inhabiting two nearby sites in northern Argentina, one comprising continuous forest and one fragmented forest. These sites differed in population density (3.25 vs. 1.04 individuals/ha), degree of home range overlap between neighboring groups (70 vs. 31%), and rate of intergroup encounters (2 vs. 0.02-1 encounters/day), though not in interbirth interval or rate of infant mortality. During a 27-month study (September 2008 through November 2010), we observed 37 mother-offspring dyads across the two sites. We found a very similar pattern of mother-offspring conflict in both populations; specifically, the sites did not differ in any of the variables used to characterize the mother-offspring relationship (the time spent in contact, the rate at which the mother makes and breaks contact, the rate at which the infant breaks contact, the rate of maternal rejection, and signs of infant distress) except one (the rate at which the infant makes contact). Although mother-offspring conflict is a dynamic process that varies over time, our results suggest that the different demographic and social contexts found at the two study sites did not have a marked effect on quantitative aspects of the mother-offspring relationship in these populations of black and gold howlers. Finally, this study suggests that the environmental variability (ecological, demographic, and social traits) leads to a set of strategies used both by infants and mothers with a main goal of conflict resolution, with mothers specifically aiming to cope with the tradeoff between current and future reproduction.

Effects of Fragmentation on the Spatial Ecology of the California Kingsnake (Lampropeltis californiae)

Abstract We investigated the spatial ecology of the California Kingsnake (Lampropeltis californiae) in unfragmented and fragmented habitat with varying patch sizes and degrees of exposure to urban edges. We radiotracked 34 Kingsnakes for up to 3 yr across four site types: interior areas of unfragmented ecological reserves, the urbanized edge of these reserves, large habitat fragments, and small habitat fragments. There was no relationship between California Kingsnake movements and the degree of exposure to urban edges and fragmentation. Home range size and movement patterns of Kingsnakes on edges and fragments resembled those in unfragmented sites. Average home-range size on each site type was smaller than the smallest fragment in which snakes were tracked. The persistence of California Kingsnakes in fragmented landscapes may be related directly to their small spatial movement patterns, home-range overlap, and ability to use urban edge habitat.

Algerian hedgehog (Atelerix algirus Lereboullet, 1842) habitat selection at the northern limit of its range

The Algerian hedgehog is an endemic, Mediterranean, insectivorous mammal which inhabits North Africa, the Eastern Iberian Peninsula, the Canary and Balearic Islands and several Mediterranean islands. Given evidence of population declines coupled with the limited information available on this species, studies are needed to contribute to a better understanding of this hedgehog. With this aim, and in particular to understand biological aspects as well as those of habitat selection, 14 Algerian hedgehogs were radio tracked in the species’ northern limit of distribution, (Baix Llobregat, a coastal district lying a few kilometres south of Barcelona City) between 2007 and 2010. The results showed that Algerian hedgehogs positively selected open grass areas and scrubs, and used fields when available, while rejecting forest and urban areas. No evidence for sex or age related patterns emerged from the data regarding home range size and overlap between individuals, although adult males have larger home ranges and move longer distances per hour than females.

Manipulation of population density and food availability affects home range sizes of African striped mouse females

An individual's home range determines its access to resources, significantly influencing its fitness. Food availability and population density are considered to be among the primary factors influencing home range sizes; however, no study has experimentally tested whether these two factors affect home range sizes independently. This is important as these two factors correlate significantly with each other, making it difficult to differentiate the effect of one from the other. First, we supplemented food to 23 female African striped mice, Rhabdomys pumilio, belonging to 15 different groups. To avoid an increase in population density by immigration, we also provided food to neighbouring groups. Although population density did not increase, female home range sizes decreased by 43.1%. In a second experiment, we manipulated population density by removing entire social groups of striped mice. We carried out experiments within 7 weeks, a period short enough to control for a change in natural food availability. Experimental decrease of population density caused an increase of female home range sizes of 44.3%. The degree of home range overlap between female striped mice was unaffected by supplemental feeding or by reduction of population density. However, female home range sizes were negatively affected by the total number of female neighbours, especially of heavier individuals. In addition, after removal, females significantly decreased their overlap with neighbouring breeding females indicating that competition with same-sex individuals shapes females' home ranges. This is the first comprehensive experimental field study demonstrating that an increase in food availability and a decrease in population density independently affect home range sizes of individuals.

Home range overlap as a driver of intelligence in primates.

Various socioecological factors have been suggested to influence cognitive capacity in primates, including challenges associated with foraging and dealing with the complexities of social life. Alexander [Alexander, 1989]. Evolution of the human psyche. In: Mellars P, Stringer C, editors. The human revolution: Behavioural and biological perspectives on the origins of modern humans. Princeton: Princeton University Press. p 455-513] proposed an integrative model for the evolution of human cognitive abilities and complex sociality that incorporates competition among coalitions of conspecifics (inter-group conflict) as a major selective pressure. However, one of the premises of this model, i.e., that when confronted with inter-group conflict selection should favor enhanced cognition, has remained empirically untested. Using a comparative approach on species data, I aimed to test the prediction that primate species (n = 104) that face greater inter-group conflict have higher cognitive abilities (indexed by endocranial volume). The degree of inter-group conflict/complexity was approximated via the variable home range overlap among groups. I found a significant relationship between home range overlap and endocranial volume, even after controlling for other predictor variables and covariates such as group size and body mass. I conclude that brain size evolution cannot be attributed exclusively to social factors such as group size, but likely reflects a variety of social and ecological determinants including inter-group conflict which poses cognitive demands on monitoring both the wider social milieu as well as spatial attributes of the habitat.

Daily, seasonal, and annual variations in individual home-range overlap of two sympatric species of deer

Behavioural tactics of animals are determined by both environmental and social factors. Among nonmigratory ungulates, most home-range studies focused either on the effect of environmental variables on home-range size or on the overlap between home ranges of different individuals. Here, as rarely in previous studies, we aim to identify the dynamics of the home range of a given individual, involving variation in home-range size and home-range overlap between periods, for two resident populations of contrasting species: red deer (Cervus elaphus L., 1758) and roe deer (Capreolus capreolus (L., 1758)). In both species, yearly and seasonal home-range fidelity was high and constant (mean of 64% in red deer and mean of 66% in roe deer), possibly because of benefits accruing from knowledge of spatial distribution of food resources and refugia. Home range in winter, when food availability was low, was larger than other seasonal home ranges for both species. Differences in body size between red deer and roe deer accounted for observed between-species differences in space use, especially when the species were active at night. Our study clearly demonstrates that patterns of variation in home-range size are similar; however, between-species differences in body size lead to differential patterns of home-range size and fidelity.

The social life of eastern water dragons: sex differences, spatial overlap and genetic relatedness

Understanding the ways individuals socialize with each other and how they differ temporally, spatially and phylogenetically is key to unravelling the evolutionary processes that shape social evolution. Our current knowledge of social evolution in vertebrates, however, has primarily come from bird and mammalian studies. Despite being largely understudied, reptiles remain an important piece of the puzzle in our study of social evolution; they represent a major class of vertebrates and, similar to mammals and birds, many are gregarious. Increasing our understanding of sociality in reptiles is important given that it would allow for comparisons across phylogenetically distinct vertebrate classes. In this study, we investigated the social structure of the eastern water dragon, Intellagama lesueurii, and found that males and females showed both preference and avoidance for members of either sex. Furthermore, we found sex differences in the extent of individual sociability: females generally formed stronger associations with one another than any other sex class (e.g. male–male, male–female). Although association patterns correlated to some extent with home range overlap, we found no evidence of a correlation with kinship. Overall, our study presents additional evidence that sociality can evolve outside the realm of kin selection.

A contact-based social network of lizards is defined by low genetic relatedness among strongly connected individuals

Social organization is widespread; even largely solitary species must organize themselves to enable contacts with mates and reduce competition with conspecifics. Although the forms of social structure can be subtle in solitary species, understanding the factors that influence them may be important for understanding how different forms of social organization evolved. We investigated the influence of genetic relatedness and spatial structure on social associations in a solitary living Australian scincid lizard, Tiliqua rugosa. We derived the genetic relatedness of 46 lizards from analysis of genotypes at 15 microsatellite DNA loci, and described social networks from GPS locations of all the lizards every 10. min for 81 days during their main activity period of the year. We found that connected male dyads were significantly more related than expected by chance, whereas connected male-female and female-female dyads had lower relatedness than expected. Among neighbouring male-male and male-female dyads, the strongest social relationships were between lizards that were the least related. Explanations of this pattern may include the avoidance of inbreeding in male-female dyads, or the direction of aggressive behaviour towards less related individuals in male-male dyads. Observed social associations (inferred through synchronous spatial proximity) were generally lower than expected from null models derived from home range overlap, and many close neighbours did not make social contact. This supports our hypothesis for the presence of deliberate avoidance between some neighbouring individuals. We suggest that lizards can discriminate between different levels of relatedness in their neighbours, directing their social interactions towards those that are less related. This highlights differences in how social associations are formed between species that are solitary (where associations form between unrelated conspecifics) and species that maintain stable social groups structured by kinship.

Intraspecific variations in home range overlaps of a semi-free range herbivore are explained by remotely sensed productivity

In this study, we used remotely sensed Enhanced Vegetation Index (EVI) as a measure of food abundance to explain intraspecific home range overlap of Global Positioning System (GPS) collared semi-free range herbivores (Bos taurus). We then tested whether seasonality (estimated using the coefficient of variation of EVI) was related to intensity of home range overlap. We also tested whether the intensity of home range overlap was related to distance from water, particularly during the dry season. We determined the intensity of home range overlap using the Utilization Distribution Overlap Index. We then modelled the intensity of home range overlap as a function of seasonality. Results show that intensity of home range overlap varied with seasonality in a non-linear U-shaped manner. In addition, results showed that at both high and low levels of seasonality, intensity of home range overlap was high while it was low at moderate levels of seasonality. Results also indicated that the intensity of home range overlap increased with distance from water during the dry period. The U-shaped relationship obtained in this study conform to the behavioural theory that predicts similar relationships between food abundance and territoriality, indicating that remotely sensed productivity is an ecologically meaningful measure of food abundance. This further amplifies the utility of the combination of GPS animal movement data and remotely sensed data in spatial ecology.

Patterns of spatial overlap in a monogamous large rodent, the crested porcupine

The crested porcupine Hystrix cristata is a large rodent which pairs for life. We studied the space use of 17 female and 9 male radio-tracked porcupines in an evergreen coastal woodland (“macchia”, EW) and in an agricultural estate (AE), with special reference to the use of cultivations. Home range sizes of male porcupines (4.72–323.40) ranged around 114ha (median) during the warm period (April–September) and 162ha during the cold one (October–March). Home ranges of females (2.48–323.40) were c. 91ha during the warm period and c. 143ha during the cold one. Habitat composition and selection changed from the cold to the warm months, with porcupines being present in agricultural areas especially in the latter. Home range overlap between members of the same pair varied from 57% to 97% (median, 75%). Habitat selection was analyzed at the second (within study area) and at the third (within home range) order of selection. Within study areas, porcupines avoided cultivations and selected habitats with dense vegetation, providing cover and food. Within home ranges, in the warm period, porcupines selected agricultural areas in EW, where this habitat represented a minor portion of the study site. In that season, the Mediterranean “macchia” is a poor source of food, forcing porcupines to travel long distances to reach feeding sites. No significant difference of habitat selection within home ranges was detected between members of the same pair. Cultivations may play a key-role for porcupine survival, especially in poor habitats, as they provide abundant food resources in the warm period.

Moving GIS research indoors: spatiotemporal analysis of agricultural animals.

A proof of concept applying wildlife ecology techniques to animal welfare science in intensive agricultural environments was conducted using non-cage laying hens. Studies of wildlife ecology regularly use Geographic Information Systems (GIS) to assess wild animal movement and behavior within environments with relatively unlimited space and finite resources. However, rather than depicting landscapes, a GIS could be developed in animal production environments to provide insight into animal behavior as an indicator of animal welfare. We developed a GIS-based approach for studying agricultural animal behavior in an environment with finite space and unlimited resources. Concurrent data from wireless body-worn location tracking sensor and video-recording systems, which depicted spatially-explicit behavior of hens (135 hens/room) in two identical indoor enclosures, were collected. The spatial configuration of specific hen behaviors, variation in home range patterns, and variation in home range overlap show that individual hens respond to the same environment differently. Such information could catalyze management practice adjustments (e.g., modifying feeder design and/or location). Genetically-similar hens exhibited diverse behavioral and spatial patterns via a proof of concept approach enabling detailed examinations of individual non-cage laying hen behavior and welfare.