Maintenance of zonation patterns in two species of flat periwinkle,Littorina obtusata and L. mariae

The zonation patterns of Littorina obtusata (L.) and Littorina mariae Sacchi et Rastelli were shown to be quite distinct on a sheltered rocky shore. L. obtusata was found at all the heights sampled; it reached peak numbers at mid shore on the alga Ascophyllum nodosum L. (Le Jol). There was no difference in the tidal height occupied by adults or juveniles; or in the mean size of L. obtusata along the vertical gradient of the shore. In contrast L. mariae occurred exclusively low on the shore, on Fucus serratus L. Translocation of the two species within their respective levels resulted in random movement after 4 days, although initial movements after 1 and 2 days were sometimes directional. Animals transplanted to the normal level of the other species showed directional movement towards their home zone; this was most pronounced after 4 days. There was no difference in the distance moved by the two species, although the distance moved did vary with tidal height, both species moving further at mid shore than low shore. Distances moved by littorinids at replicate areas in the low shore were similar but those at mid shore did vary. There was an interaction between the species and the different tidal heights which revealed that transplanted species moved further than translocated species at the same tidal level. However, this was only significant in the case of L. mariae. It is suggested that the close relationship between the winkles and their host algae may direct the homing behaviour of displaced individuals.     

Home range and habitat use of translocated endangered species,Cottus koreanus,in South Korea

The home range and characteristics of Cottus koreanus were investigated using passive integrated transponder (PIT) telemetry in the Gulji Stream, Korea, where the target species was artificially translocated. After release, tagged individuals moved up to 78?m away from the release site in search of proper habitats. The average distance moved until settlement was 17.1?m. The observed home range of settled individuals had longitudinal sections of 9.9?±?3.6?m and surface areas of 7.2?±?2.7?m². This is comparable to congeneric species that inhabit similar ecological habitats. Once individuals had settled, they rarely moved from that site except during the spring season. The typical microhabitat characteristics of the sites where the released individuals settled are: water depth of 5–10?cm, water velocity of 0.1–0.3?m?s^?1, and the size of boulders and cobbles of 10–20?cm in diameter. This study of translocated C. koreanus individuals provides detailed information about habitats that can be used for effective habitat restoration and successful translocations attempts of this species.     

Movements and Swimming Behavior of Three Species of Sharks in La Jolla Canyon, California

We tracked six individuals of three shark species, the shortfin mako, Isurus oxyrinchus, great white, Carcharodon carcharias, and blue, Prionace glauca, near the submarine canyon off La Jolla, southern California during the summers of 1995 and 1997. The duration of tracking ranged from 2 to 38 h per shark. The mode of travel differed in one respect among species. The rate of movement of the endothermic species, the mako and white shark, exceeded that of the ectothermic species, the blue shark. Similarities among species were more common. Firstly, individuals of all three species swam in a directional manner. Secondly, individuals constantly moved up and down in the water column, exhibiting oscillatory or yo-yo swimming. Thirdly, members of the three species swam at the surface for prolonged periods. Finally, the movements of the mako and white sharks were at times loosely associated with bottom topography. We discuss the various adaptive advantages that have been proposed for these behavioral patterns. Oscillatory swimming has been attributed to the following: (1) heating the body in the warm surface waters after swimming in cold, deep water, (2) alternating between two strata of water, one carrying chemical information as to its source, and deriving a direction to that stratum's origin, (3) conserving energy by quickly propelling oneself upward with many tail beats and slowly gliding downward with few beats, and (4) descending to where magnetic gradients are steeper, more perceptible, and useful to guide migratory movements. At the surface, an individual would be able to swim in a straight line by using following features as a reference: (1) celestial bodies, (2) polarized light, or (3) the earth's main dipole field. Furthermore, an individual would conserve energy because of the greater ease to maintaining a warm body in the heated surface waters.     

Reptiles and frogs use most land cover types as habitat in a fine‐grained agricultural landscape

Agricultural landscapes comprise much of the earth's terrestrial surface. However, knowledge about how animals use and move through these landscapes is limited, especially for small and cryptic taxa, such as reptiles and amphibians. We aimed to understand the influence of land use on reptile and frog movement in a fine‐grained grazing landscape. We surveyed reptiles and frogs using pitfall and funnel traps in transects located in five land use types: 1) woodland remnants, 2) grazed pastures, 3) coarse woody debris added to grazed pastures, 4) fences in grazed pastures and 5) linear plantings within grazed pastures. We found that the different land cover types influenced the types and distances moved by different species and groups of species. Reptiles moved both within, and out of, grazed paddocks more than they did in woodland remnants. In contrast, frogs exhibited varying movement behaviours. The smooth toadlet (Uperoleia laevigata) moved more often and longer distances within remnants than within paddocks. The spotted marsh frog (Limnodynastes tasmaniensis) moved out of grazed pastures more than out of pastures with coarse woody debris added or fences and were never recaptured in plantings. We found that most recaptured reptiles and frogs (76.3%) did not move between trapping arrays, which added to evidence that they perceived most of the land cover types as habitat. We suggest that even simple fences may provide conduits for movement in the agricultural landscape for frogs. Otherwise, most reptile and frog species used all land cover types as habitat, though of varying quality. Reptiles appeared to perceive the woodland remnants as the highest quality habitat. This landscape is fine‐grained which may facilitate movement and persistence due to high heterogeneity in vegetation cover over short distances. Therefore, intensification and increasing the size of human land use may have negative impacts on these taxa.     

Patterns of Fish Movement on Eastern Tasmanian Rocky Reefs

We assessed small-scale movement patterns of fishes on three eastern Tasmanian reefs by divers visually resighting 1040 individuals of 16 species marked with unique colour-coded tags. With the possible exception of the monacanthid Acanthaluteres vittiger, common species showed high fidelity to site, with individuals generally resighted <100m from the initial tagging site and remaining near the tagging site throughout the 1 year duration of study. The wrasses Pictilabrus laticlavius and Notolabrus tetricus were more sedentary than Notolabrus fucicola and the monacanthids Meuschenia australis and Meuschenia freycineti. Body length, sex, water temperature and time since tagging had little influence on distance moved compared to variation between individuals, other than movement distance increasing with body length for N. tetricus. Movement patterns were generally consistent at all three sites, although mean distance moved by N. fucicola was double at Swanport and Return Point compared to Lobster Point. N. tetricus but not P. laticlavius emigrated from areas artificially cleared of macroalgae. The sedentary nature of most small- to medium-sized reef fish species, particularly labrids, indicates that relatively small (1km diameter) marine protected areas should generally provide conservation benefits for these fishes but few `spillover' benefits in surrounding areas.     

Translocation of the Eastern Bristlebird 1: radio‐tracking of post‐release movements

Summary Translocating birds to a new area of habitat to restore or supplement depleted populations may pose a significant threat to the translocated individuals. While for many species, translocated individuals appear to move larger distances than resident animals, species with poor dispersal capacity may be restricted in movements and translocation methods may need to accommodate differences in movements to ensure success. In this study, designed to provide insights to inform our broader programme of translocations in New South Wales, Australia, we investigated post‐release movements in the endangered, semi‐flightless Eastern Bristlebird (Dasyornis brachypterus). We predicted that movements would be minimal, with few differences between males and females, similar to published information for a resident un‐manipulated population. Following the release of 45 birds at a host location at Jervis Bay, NSW, over a 3‐year programme, we followed individuals for up to 2 weeks using radio‐tracking. The translocated birds had larger maximum movements and moved through much larger home ranges than non‐translocated individuals from the resident population. Translocated birds moved 300 m further after release when conspecifics were present. Males moved further than females and tended to have larger home ranges, although average daily displacement did not differ. We concluded that the semi‐flightlessness of the species does not result in minimal movements. Release at a small number of locations in the new habitat was considered appropriate for the species, as animals seem to move enough to find new unoccupied areas in a relatively short period. This work provided us with increasing confidence to continue with further translocations.     

Individually mark–mass release–resight study elucidates effects of patch characteristics and distance on host patch location by an insect herbivore

1. How organisms locate their hosts is of fundamental importance in a variety of basic and applied ecological fields, including population dynamics, invasive species management and biological control. However, tracking movement of small organisms, such as insects, poses significant logistical challenges. 2. Mass‐release and individual–mark–recapture techniques were combined in an individually mark–mass release–resight (IMMRR) approach to track the movement of over 2000 adult insects in an economically important plant–herbivore system. Despite its widespread use for the biological control of the invasive thistle Carduus nutans, the host‐finding behaviour of the thistle head weevil Rhinocyllus conicus has not previously been studied. Insects were released at different distances from a mosaic of artificially created host patches with different areas and number of plants to assess the ecological determinants of patch finding. 3. The study was able to characterize the within‐season dispersal abilities and between‐patch movement patterns of R. conicus. Weevils found host plant patches over 900 m away. Large patches, with tall plants, situated close to the nearest release point had the highest first R. conicus resights. Patch area and plant density had no effect on the number of weevils resighted per plant; however, R. conicus individuals were more likely to disperse out of small patches and into large patches. 4. By understanding how R. conicus locates host patches of C. nutans, management activities for the control of this invasive thistle can be better informed. A deeper mechanistic understanding of host location will also improve prediction of coupled plant–herbivore spatial dynamics in general.     

Succession and fluctuation in Artemisia dominated grassland

Vegetation dynamics were studied from 1940 to 1978 in two grazed pastures and associated exclosures in sand sagebrush (Artemisia filifolia) dominated grassland, western Oklahoma, USA. In both pastures and one exclosure, pattern of vegetation change reflected fluctuation rather than succession. In the other exclosure, the grassland exhibited a directional change from annual grasses and forbs to dominance by perennial grasses. Rate of change was consistent during the 39 year period. Cover of grasses increased more in grazed than ungrazed areas. Grass cover was negatively correlated with high air temperatures early in the growing season. Forb cover remained relatively constant over time and shrub cover peaked during the 1960s. Abundance of annuals and cool season species was positively correlated with rainfall early in the growing season.Species diversity and richness were lowest in the ungrazed areas, as a result of increased dominance by perennial grasses such as Schizachyrium scoparium. In pastures and exclosures, richness was positively correlated with growing season precipitation. Cover of the common species differed among sample areas within years and fluctuated between years. Few general patterns emerged from correlations of environmental variables with cover of individual species. In general, vegetation dynamics in these sand sagebrush grasslands reflect a tradeoff in that total cover changes little over time because the loss of some species is compensated for by increased growth of others. Such trade-offs reflect the individualistic response of the component species within each pasture or exclosure. Although changes in growth form composition were related to climatic fluctuation, broad-scale climatic variables could not successfully predict small-scale patterns of change by individual species over time.     

Movement behaviour of the pine weevil Hylobius abietis in relation to soil type: an arena experiment

Pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), movement behaviour on different substrates was studied in an indoor arena using a video camera and digital image processing technique. We analysed individual variation in movement characteristics, i.e. turning angles, movement directions, and distance moved per unit time on the bare and level arena surface which consisted of mineral soil (sand) and/or humus sections in various spatial configurations. Pine weevils on humus did not turn back when they came to the border with the sand. However, most individuals moved faster on sand than on humus. Thus, the results suggest that interactions between substrate differences and individual movement behaviour may to some extent explain why pine weevils have been observed to feed less frequently on coniferous seedlings planted on mineral soil than on those planted on humus.     

Migratory movements of pacu, Piaractus mesopotamicus, in the highly impounded Paraná River

A mark‐recapture study was conducted in 1997–2005 to investigate movements of stocked pacu, Piaractus mesopotamicus, in the Paraná River Basin of Brazil, Paraguay, and Argentina. Fish raised in cages within the Itaipu Reservoir and in ponds were tagged externally (n = 2976) and released in the Itaipu Reservoir (53.2%) and bays of its major tributaries (46.8%). In total, 367 fish (12.3%) were recaptured. In all, 91% of the pacu moved away from the release site; upstream movements were more extensive than downstream movements. Pacu traveled upstream a maximum of 422 km (average of 41.3 km) at a maximum rate of 26.4 km day⁻¹ (av. 0.8). Downstream movements were limited in terms of number of individuals and distance moved. Fish released during the wet season moved farther than those released during the dry season, and feeding rather than spawning might have been the compelling reason for movement. Although fish passed downstream through dams, none of the marked fish were detected to have moved upstream through the passage facilities. Pacu showed movement patterns not radically different from those of other neotropical migratory species, but their migratory movements may not be as extensive as those of other large migratory species in the basin.     

Secondary seed dispersal of Erodiophyllum elderi,a patchily distributed short‐lived perennial in the arid lands of Australia

We investigated secondary dispersal of propagules of Erodiophyllum elderi (Asteraceae), a short‐lived perennial plant growing in small patches in the arid lands of southern Australia. In spite of its importance for population dynamics, secondary dispersal is a little understood process. We monitored the dispersal of 2280 large woody capitula (seed heads) released in six E. elderi patches for 9 months. Colour‐coded seed heads were located at night using UV light and their distance and direction from the release point were measured. Over the 9‐month period, more seed heads moved, and those that did, moved further in areas with high herbivore activity. Overall dispersal distance across the ground was limited to less than 30 m. Dispersal patterns were related to the topographical slope at the release site: seed heads moved further, and more dispersed on steeper slopes unless the steep slopes had sandy soil in which case seed heads were buried, caught or there was reduced sheet water flow limiting their dispersal potential. After several months, seed head dispersal virtually ceased as seed heads became stuck in the debris and soil after heavy rains or further dispersal became unlikely when seed heads reached locally low‐lying areas. Secondary dispersal patterns suggest two distinctly different influences associated with the presence of herbivores: the direct movement of seed heads by trampling from sheep (an introduced herbivore) and the indirect effect of a reduced standing biomass from grazing. Reduced vegetation cover allows seed head redistribution via sheet water flow during large rainfall events.     

Mechanisms of competition among insectivorous mammals

Summary This study investigates the mechanisms of competition between congeneric pairs of insectivorous mammals in two communities in Australia and England. Direct field observations showed that physical interactions between species do not occur, whereas conspecific encounters are frequent. In field enclosures the smaller, subordinate species in each community (Antechinus stuartii: Marsupialia: Sorex minutus: Eutheria) remained alert in the presence of the dominant species (A. swainsonii, S. araneus), and moved quickly away when the latter approached. The rate of prey capture by subordinate individuals also increased immediately after removal of the dominants. Hourly removals of some individuals of the dominant species in each community over 24 h produced hourly increases in the numbers of subordinate individuals that were captured. The rapidity of these responses suggests strongly that the dominant insectivores in each community interfered with the resource use of the subordinate species. Biomass of invertebrates increased inconsistently or slowly within 3 months of removal of the dominant insectivores; hence the rapid responses by subordinate individuals in experiments were not due to simple exploitation or tracking of resource levels. The subordinate insectivores probably detected and avoided contact with dominants instantaneously using auditory or olfactory cues; reciprocal avoidance of congeneric odours was demonstrated using odour-scented traps. Insectivorous mammals may usually compete by interference (or encounter competition, sensu Schoener 1983). For dominant species within communities the cost of interference is minimal and the benefit of gaining exclusive access to resource-rich microhabitats is high. Conversely for subordinate species the benefit of temporarily exploiting the same rich microhabitats may exceed the small costs of vigilance and movement to nearby refugia.     

The impact of grazing intensity on soil characteristics of Stipa grandis and Stipa bungeana steppe in northern China (autonomous region of Ningxia)

The effects of grazing intensity on selected soil characteristics in the feather-grass steppes of the autonomous region of Ningxia (northern China) were investigated by a comparison of non-grazed areas (grazing intensity 0), slightly grazed areas (grazing intensity I), moderately grazed areas (II), intensively grazed areas (III) and over-grazed areas (IV). Even in areas used only minimally for grazing activities (I), a serious increase (doubling) in soil hardness was apparent in the upper soil layer. A continual decrease in organic matter in the surface soil can be correlated directly to soil compaction. The content of organic matter in soil of degree IV amounts to only a third of the organic matter found in non-grazed areas. This decrease can be attributed partly to the poor living conditions for soil organisms in compacted soils, but also to a significant reduction in litter. This is because intensive grazing causes reduced vegetation cover leading to litter being blown away by wind or washed away by heavy rainfall. Thus in level III hardly any plant litter remained to be incorporated into the soil as humus. Likewise root density also suffered its largest decrease in areas with a grazing intensity level III. With regard to the content of nitrogen and phosphorous (total and available) hardly any difference between soils of grazing intensity 0 and I was observed, whereas a noticeable decrease was apparent between levels I and II. Available Potassium was similar for all grazing levels. The pH-value of the soil solution is not significantly affected by grazing. We did not observe differences in the soils of the two main types of steppe vegetation (Stipa grandis and Stipa bungeana steppe) in response to grazing. Only the amount of litter in the S. grandis-steppe in non-grazed or slightly grazed areas is noticeably higher than in the S. bungeana steppe.     

Evidence of a link between demographic rates and species habitat suitability from post release movements in a reinforced bird population

Despite the increasing use of species distribution models for predicting current or future animal distribution, only a few studies have linked the gradient of habitat suitability (HS) to demographic parameters. While such approaches can improve the reliability of models, they can help to better predict the response of species to changes in HS over space and time, as induced by ongoing global change. Here, we tested whether the spatial variation in HS along the individual movement path is related to survival, using extensive tracking data collected from captive‐bred individuals translocated to reinforce the wild populations of houbara bustard. We first modelled and mapped the HS from presence data of wild individuals using niche models in a consensus framework. We further analysed survival of released individuals using capture–recapture modelling and its links to HS, as the trend in suitability from the release sites along movements. We found that the survival of released individuals was related to changes in HS along their movements. For instance, individuals which moved to sites of lower HS than their release sites have lower survival probabilities than the others, independently of the HS of the release sites and daily movement rate. Our results provide an empirical support of the relationship between HS and survival, a major fitness component.     

西藏飞蝗蝗蝻群集迁移特性及其群集效应

西藏飞蝗Locusta migratoria tibetnsis Chen暴发成灾的重要原因之一是蝗蝻具有群集迁移危害习性。为阐明西藏飞蝗灾变的行为机制,为西藏飞蝗的监测预警和防治提供科学依据,利用视频跟踪技术测定了自然环境中西藏飞蝗蝗蝻群集迁移的运动速度、方向,建立自推进粒子模型模拟蝗蝻群集迁移行为,分析群集迁移效应。结果表明,①不同自然环境中的西藏飞蝗蝗蝻在群集迁移过程中,群体内个体的运动表现出定向集体运动,群集迁移速度为0.1256 m/s,0.2 m以内的个体蝗蝻方向趋向一致。沙滩、翻耕农田和草地蝗蝻群运动一致性参数均较高,分别为0.8502、0.7870和0.6987。②西藏飞蝗蝗蝻群由分散运动转变为群集迁移存在临界密度,密度较低时群体内个体分散运动,当蝗蝻密度达到12-15头/m²时,蝗蝻群体由分散运动转变为高度一致的群集迁移运动。③蝗蝻群通过群集迁移可以显著增加迁移距离,随机运动蝗蝻1 d扩展只有70-80 m,而群集迁移1 d最大距离可达2.5 km。蝗蝻群集迁移可以提高发现特别是远距离食物等资源的概率,使群体中更多的个体受益。④尽管未发现室外蝗蝻群存在先验个体,但模拟发现在群集迁移群体中,只需要少数先验个体（3%-5%）即可引导整个蝗蝻群运动。     

Food Preference of Wireworms Analyzed with Multinomial Logit Models

Many species of wireworms (larvae of click beetles, Elateridae) are poly- phagous root herbivores. In grasslands under restoration succession with various grass species, we aim to determine the role of wireworms in aboveground vegetation succession. Therefore, it is crucial to know whether wireworms prefer some food plants to others. We have investigated the root preference to different grass species for Agriotes obscurus and Athous haemorrhoidalis and whether these preferences can be explained by covariates. In Experiment 1, individual wireworms could choose between four different plants, one of each species (Anthoxanthum odoratum, Festuca rubra, Holcus lanatus, and Lolium perenne). In Experiment 2, groups of wireworms were released into the soil in the center of 16 plants (4 from each species). We used multinomial logit models (MLMs) to analze the data. In the appendix the use of multinomial response models is clarified with a fictitious example, using the SAS statistic software package. No preference was found in Experiment 1. In Experiment 2 we found differences in attractiveness of plant species depending on wireworm species: A. obscurus preferred grass species from nutrient-rich grasslands (L. perenne and H. lanatus). Both wireworm species disliked F. rubra. The distance from the release point influenced the probability of being found at a certain place at the end of the experiment: wireworms tended to stay in the proximity of the release point. A. haemorrhoidalis was more often found farther from the point of release than A. obscurus. Dispersal was farther from the release point in experiments with young plants (6 weeks) compared to older ones (9 weeks). Results are discussed in a broad ecological context.     

Movements and Site Fidelity of two Juvenile Fish Species Using Surf Zone Nursery Habitats Along The Southeastern North Carolina Coast

We examined the extent of movements of juvenile Florida pompano, Trachinotus carolinus, and gulf kingfish, Menticirrhus littoralis, along an open ocean beach. Fishes were collected by seine at three sites along Masonboro Island and Carolina Beach, NC between 7 June and 7 July 1995. All specimens 40 mm standard length (SL) were tagged with coded wire tags and released at the capture sites. Between 7 July and 9 August and on 15–16 September Masonboro Island and northern Carolina Beach were surveyed for tagged fish. A controlled tag mortality/retention study was conducted for both species. Overall, 1569 Florida pompano (40–135 mm SL) were tagged. Sixty-one (3.9%) of these were recaptured, and only eight moved away from the original tagging sites. The largest movements by two Florida pompano were 2.1 and 10.5 km. Many fish remained at their original tagging sites for 21–27 days. Of 488 gulf kingfish (36–158 mm SL) tagged, 16 (3.3%) were recaptured. Gulf kingfish also exhibited little movement away from tagging sites during the study, with individuals remaining at original tagging sites up to 21 days. Stock size estimates for Florida pompano ranged from 3354 to 4670 among the tagging sites, with densities ranging from 1.9 to 2.6 fish m^–2. The remarkable site fidelity exhibited by these two species suggests that resources were not limiting or that predation pressure was not high enough to cause large scale movements during the study. This implies that local disturbances could impact behavior or survival of juvenile fishes in the surf zone.     

The effect of anthropogenic resources on the space-use patterns of golden jackals

We studied the influence of agricultural villages on space-use patterns of golden jackals (Canis aureus Linnaeus) in the Mediterranean region of Israel. Villages in our research area attract jackals due to poor sanitation conditions in and around villages. As resources in these villages are abundant and predictable, we expected that space-use patterns of jackals near those villages, including home-range characteristics and movement paths, would differ from those of jackals inhabiting more natural areas. Using radio-locations from 16 individuals (8 near villages and 8 from more natural areas), we found that mean home-range size of jackals close to villages was 6.6 ± 4.5 km², smaller than mean home-range size of jackals in more natural areas (21.2 ± 9.3 km², P = 0.001). Similarly, core area size of jackals near villages was 1.2 ± 0.92 km², compared to 3.5 ± 1.6 km² for individuals inhabiting more natural areas (P = 0.004). The core area/home-range ratio was greater for jackals near villages than for those occupying more natural areas (0.122 ± 0.045 vs. 0.095 ± 0.037, respectively, P = 0.004). Jackals moved little during the day, with day ranges smaller for jackals near villages than away from them (1.65 ± 0.67 vs. 7.5 ± 5.6 km², respectively, P = 0.028). However, jackals near villages moved as much at night as did jackals in more natural areas, although movement was in a less directional manner. Changes in distribution and predictability of resources due to anthropogenic activity affect not only the home-range size of jackals, but also how they utilize and move through space. © 2011 The Wildlife Society.     

Vertical structure of wet grasslands under grazed and non‐grazed conditions in Tierra del Fuego

Abstract. We studied the vertical structure of wet grazed grasslands in Tierra del Fuego (southern Argentina). A point quadrat method was developed using a fine needle graduated in cm. The vertical and horizontal frequency of species and organs was quantified in samples collected from non‐grazed and grazed plots in the field. There was vertical stratification in both types of samples, but only in the first eight cm above the ground in grazed samples, with a dominance of Caltha sagittata. In non‐grazed samples graminoids grew taller than forbs and their inflorescences were an important element of the canopy structure. In both treatments, vertical species diversity was maximum in the lower part of the canopy, although diversity was significantly higher in grazed pots. In grazed samples, Caltha sagittata was the dominant species in 46% of samples and its leaves occupied 35% of the upper canopy. In the non‐grazed samples, Hordeum pubiflorum and Festuca magellanica were dominant in 63% of the samples, with H. pubiflorum leaves occupying 55% of the upper canopy. Comparing species by pairs, significant differences in vertical position were maintained in non‐grazed versus grazed pots. It is concluded that vertical stratification occurs even in the shortest communities. In this community, forb species grew close to the ground in the grazed areas, while forbs grew in the gaps and grasses above them in the non‐grazed areas. The main differences were in the relative dominance of forb and grass species and the presence of inflorescences.     

Translocation of overabundant species: Implications for translocated individuals

Effective management of overabundant animal populations is a difficult challenge for wildlife managers around the globe. Translocation is often considered a viable management tool, whereby individual animals are removed from areas of high population density and released in areas where densities are lower. Typically, the success of a translocation program is measured at the population source, with little attention given to the fate of translocated individuals. Here we use a koala (Phascolarctos cinereus) translocation program from southeastern Australia as a case study to investigate the effects of translocation on individual animals. The koala is an iconic species that occurs at high densities in some parts of its southern range, leading to numerous conservation and animal welfare issues. Between 1997 and 2007 over 3,000 koalas from a high-density island population were captured, surgically sterilized, and translocated to the mainland. Annual post-translocation surveys at release sites revealed densities of ≤0.4 koalas/ha, despite release densities of 1.0 koala/ha. Radiotracking studies indicate that low densities were because of both mortality and high dispersal of translocated individuals. We observed a mortality rate of 37.5% for translocated koalas in the first 12 months post-release. No deaths occurred among animals that were not sterilized and translocated. Translocated koalas moved greater distances than non-translocated animals. Monitoring of translocated individuals should be performed routinely during translocation programs for overabundant species. Due consideration must be given to what is an acceptable level of mortality for translocated individuals. Although often considered an ethically acceptable management technique (especially for iconic and charismatic species), translocation may not always be the best option from an animal welfare perspective. © 2012 The Wildlife Society.