Spatial Use and Survivorship of Translocated Wild-Caught Texas Horned Lizards

The Texas horned lizard (Phrynosoma cornutum), a state threatened species in Texas, USA, appears to be declining throughout much of its distribution. Because of popular interest in restoring lizard populations, we conducted a 3-year radio-telemetric study to evaluate the feasibility of reintroducing Texas horned lizards into previously occupied areas with suitable habitat characteristics. We translocated lizards from natural populations in western Texas to the McGillivray and Leona McKie Muse Wildlife Management Area (MWMA) in the Cross Timbers and Prairies of north-central Texas, an ecoregion that has experienced apparent local extirpations of horned lizards. We translocated lizards after partly restoring a 32.5-ha portion of the MWMA from ashe juniper (Juniperus ashei)-honey mesquite (Prosopis glandulosa) woodland to mid-grass prairie. After a 10-day acclimation period and soft release, we tracked 57 horned lizards from March 2014 to October 2016 to evaluate daily movements, spatial use, sources of mortality, reproduction, and changes in body condition. Daily movement averages (1.16–174.18 m) and area used by individuals (<0.01–6.81 ha) were similar to those recorded for natural populations, with peaks in movement occurring in May and June. Annual survivorship for individuals (1.1–47.2%) was also similar to that reported from natural populations; however, survivorship declined across the 3 active seasons. Although mortality of translocated lizards was high, body condition remained relatively stable across active seasons, and reproduction occurred each year, indicating that translocation could be a viable option for restoring horned lizard populations to previously occupied parts of their range. © 2019 The Wildlife Society.     

Homing,dispersal and mortality after translocation of long-lived land snails Placostylus ambagiosus and P. hongii (Gastropoda: Bothriembryontidae) in New Zealand

Between 1997 and 2003 mortality and yearly movements including homing (philopatry) of long-lived Placostylus ambagiosus and P. hongii land snails were studied when left in situ or exchanged between nearby sites in New Zealand. Harmonic radar transponders, attached to shells, increased recapture rates but might have increased emigration. Manipulation (translocation exchanges vs. control) caused no detectable changes but sample sizes were small. At Cape Maria van Diemen, 20% of P. ambagiosus homed after translocation although 90% died during widespread mortality. No P. ambagiosus snails homed at Surville Cliffs where 2.4% died and 26% emigrated. At Whareana Bay, 23% homed, 19% died, 8%–15% stayed where released and 58% emigrated. Mortality of P. hongii on Tawhiti Rahi Island, Poor Knights Islands, was 2% after 1 year. When transferred 10–84?m, 78% homed within a year, 2% went elsewhere and 20% were not found. However, 24% of those transferred 30–84?m returned to their release sites after homing. When left in situ, 60% remained nearby, 8% moved elsewhere and 30% were not found. There was an indication that habitat quality might influence emigration. Results are briefly discussed in relation to possible future translocations to conserve genetic variability and restore faunas.     

The Effects of Winter Burning and Grazing on Resources and Survival of Texas Horned Lizards in a Thornscrub Ecosystem

ABSTRACT The ecological effects of land-use practices on reptiles, especially endangered or threatened species, are of conservation and scientific interest. We describe the effects of rotational livestock grazing and prescribed winter burning on resources and survival of the Texas horned lizard (Phrynosoma cornutum) during the summers of 1998 to 2001 in southern Texas, USA. We evaluated survival rates of Texas horned lizards (n = 111) on 6 study sites encompassing 5 different burning and grazing treatments. We also measured indices of cover (i.e., vegetation) and food abundance (i.e., harvester ants [Pogonomyrmex rugosus]). We telemetered and relocated adult lizards daily. We divided the study into 2 seasons, spring (15 Apr–30 Jun) and summer (1 Jul–15 Aug), corresponding to the relative activity of horned lizards. Winter burning provided an increase in food resources and led to increased survival of Texas horned lizards in the second growing season after fire, but grazing-induced changes in vegetation cover reduced survival, likely by increasing lizard vulnerability. Fire and grazing reduced litter and increased bare ground and forb cover but did not affect woody vegetation. Ant activity was greater in burned sites and varied with grazing level, season, and year. Summer survival functions of horned lizards varied by burning treatment, with higher survival observed on burned sites in the second year after burning. Survival rates were ordered from highest in ungrazed sites to lowest in heavily grazed sites. We recognize the limitations of our work resulting from a lack of spatial replication of treatments. However, our mensurative study provides fertile ground for future hypothesis testing regarding the effects of land management on shrubland and grassland reptiles. We propose that future studies focus on the population consequences of variation in burn frequency, burn timing, and grazing intensity.     

Ranging Behavior of an Arboreal Marsupial in a Plantation Landscape

Forests are becoming increasingly fragmented, primarily because of their conversion to production landscapes. Animals occupying modified landscapes may need to expand their ranges and move longer distances between remnant forest patches to find resources. The establishment of plantations in fragmented landscapes, however, may provide complementary habitat for wildlife and improve connectivity, reducing the amount of movement required. Our objective was to determine the influence of plantations on koala (Phascolarctos cinereus) habitat use and test 2 competing hypotheses on the relationship between plantations and range size. We deployed global positioning system and very high frequency collars on 40 koalas in 2 landscapes (plantation and non-plantation) in Victoria, Australia. From 68,216 tracking points collected over an 8-month period, we calculated and compared seasonal home range size and habitat use between landscapes. There was no difference in range size, the size and number of core use areas, or the distance between core use areas between plantation and non-plantation landscapes. Plantations extend existing koala habitat and facilitate koala movement through a landscape; however, remnant native vegetation is still more frequently used. Consequently, native vegetation (even fragmented, linear roadside vegetation) is of high conservation importance for the persistence of koalas in modified landscapes. © 2020 The Wildlife Society.     

Movement Patterns and Spatial Relationships Among African Forest Elephants

African forest elephants (Loxodonta cyclotis) are of immediate conservation concern, yet are understudied due to inaccessible habitats. We analyzed the home range size and overlap of six adult females. Home ranges were among the smallest for all elephant species and individuals were positioned adjacent to one another with minimal overlap.     

Movement and pattern of activity of the roach in the River Spree, Germany

Water body and bank structure use of adult roach Rutilus rutilus were examined to increase the knowledge of the most abundant species in the River Spree, Germany. Six tracking series were conducted between 1994 and 1995 to analyse the seasonal and diel movements of the fish. In each series, four to 12 roach were tagged externally and located every 2 h for up to 14 days using radiotelemetry. Roach were highly active, moving up to 10 km downstream to Lake Dämeritzsee, and up to 6 km upstream from their release site. The fish, which mostly swam greater distances upstream during the day and downstream at night, were most active during the spawning season. Their habitat range varied greatly. Close-range habitat, based on 50% of all radiolocations, varied between 5 and 1350 m (mean, ̄=296 m). Wide-range habitat, based on 90% of all radiolocations, varied between 75 and 3820 m (̄=1006 m). The fish preferred different sections of water at different times of year, casting doubt on the relevance of the term home range. Generally, roach stayed close to the bank structures of the main channel during the day and moved to the stagnant waters at night. Consequently, they were most active at dawn and dusk.     

Spatial ecology of arboreal snakes (Hoplocephalus stephensii,Elapidae) in an eastern Australian forest

Abstract Stephens' Banded Snakes (Hoplocephalus stephensii Krefft 1869) are large (to 1 m), highly arboreal elapid snakes, restricted to mesic forested areas along the eastern coast of Australia. Radiotelemetric monitoring of 16 individuals at Whian Whian State Forest in north‐eastern New South Wales over 25 months provided the first data on spatial ecology of this threatened taxon. Two major influences on movements by Stephens' Banded Snakes were identified: the distribution of large hollow‐bearing trees, and the avoidance of conspecifics. Radiotracked snakes were sedentary inside tree hollows for extended periods (mean = 8 days) during their active season, interrupted by occasional long (mean = 124 m) nocturnal movements to another shelter tree. Snakes travelled on the ground rather than within the canopy, and thus were potentially exposed to terrestrial predators. Although the home ranges of the radiotracked snakes overlapped substantially (mean = 27%), simultaneous occupancy of ‘shared’ shelter trees was less common than expected by chance. Hence, we conclude that adult Stephens' Banded Snakes generally avoid the presence of conspecifics. Snakes used from five to 30 shelter trees and home ranges of male snakes were larger than those of females (mean = 20.2 vs 5.4 ha). The large spatial scale of these movements, and limited overlap among individuals, means that a viable population of this taxon requires a large area of contiguous forest. This requirement may explain why the species has not persisted in small forest fragments.     

Patterns of movement and habitat use by leafy seadragons tracked ultrasonically

Nine adult leafy seadragons Phycodurus eques were tracked using ultrasonic telemetry for between 2-10 days around West Island, Australia. All fish except one moved within well-defined home ranges of up to 5 ha (using minimum convex polygon method). Short bursts of movement (at average velocities of 2-17 m h⁻¹) punctuated long periods (up to 68 h) without movement. The exceptional fish moved almost in a straight line away from its tagging location near the end of the tracking period, at a maximum velocity of 146 m h⁻¹. There was no constant diel pattern in movements; some fish moved more at night, others during the day. The time leafy seadragons spent over particular habitats compared to the area of those habitats available at the study site was greater for Posidonia seagrass, about as expected for kelp-covered reefs and bare sand patches, and less than expected for Amphibolis seagrass and boulders covered with brown algae. In searching for tagging effects, a comparison of movement immediately after tagging showed no difference with subsequent movements for most fish. The lack of tagging effect may be because the transmitter can be attached to the bony appendages away from the body of the fish. There was no sign of damage to fish upon removal of transmitters after tracking.     

Habitat use and early winter movements by juvenile Atlantic cod in a coastal area of Newfoundland

Acoustic telemetry was used to monitor the movements and landscape scale habitat use of age 2–3 year juvenile Atlantic cod Gadus morhua in Newman Sound, a coastal fjord of Newfoundland, during late autumn and early winter (24 October 1999 to 22 January 2000). Substratum, bathymetric relief and depth use were studied to determine if it differed from the pattern expected given an absence of selectivity (habitat use proportional to habitat availability). Prior to winter migrations, most Atlantic cod maintained small home ranges (0·5–33·4 ha, median = 2·1 ha) although a few individuals moved more widely. No relationship between total length (L_T) and home range size was detected. In Inner Newman Sound, Atlantic cod occupied depths of 10–29 m more than expected given availability, while depths of 0–9 and 40–59 m were underutilized. No significant relationship between depth and L_T was detected. Areas of medium (5–10%) or high (>10%) bathymetric relief and boulder or kelp habitats were used significantly more than expected given the availability of these habitats. Sand and eelgrass substrata were underutilized given availability, although many Atlantic cod used sandy‐bottomed areas to some degree. Flexibility in habitat use by the individuals that were studied suggested reduced predation risk relative to younger conspecifics. Winter migrations to deeper water beyond Newman Sound began in mid‐November, coinciding with the disappearance of the thermocline, and continued until 27 December. Approximately 30% of monitored individuals did not migrate and maintained their home ranges into the winter season. No significant differences in L_T between migrating and resident groups were detected, however, the condition of migrating fish was significantly higher than in resident fish. This finding supports the theory that feeding history plays a role in the decision to undertake migration.     

Short-term Movements of Juvenile and Neonate Sandbar Sharks, Carcharhinus plumbeus, on their Nursery Grounds in Delaware Bay

We investigated short-term movements of neonate and juvenile sandbar sharks, Carcharhinus plumbeus, on their nursery grounds in Delaware Bay. The majority of sharks tracked limited their movements to water less than 5m deep, remained within 5km of the coastline, and occupied oblong activity spaces along the coast. In addition to site-attached coastal movements observed, several sharks moved entirely across Delaware Bay or spent considerable time in deeper portions of the central bay. Sharks tracked on the New Jersey side of the bay tended to spend more time in deeper water, farther from shore than sharks tracked on the Delaware side. Observation-area curves estimated that optimal tracking time for sandbar sharks in Delaware Bay was 41h. Indices of site attachment showed that movement patterns of tracked sandbar sharks varied from nomadic to home ranging. There was no significant difference in rate of movement for day/night, crepuscular periods, or between juveniles and neonates. In general, young sandbar sharks patrolled the coast and appeared to be site attached to some extent, but were capable of making longer excursions, including movement entirely across Delaware Bay.     

Movements of wintering Dunlin Calidris alpina and changing habitat availability in an agricultural wetland landscape

Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999–2000. By tracking movements of 15 (early winter) and 12 (late winter) radiomarked individuals, we calculated home ranges and characterized presence/absence of a preference for shorebird foraging habitat during each winter period. Between periods, we compared: (1) percentage of shorebird habitat in home ranges to its availability in the landscape (regional preference), (2) percentage of radio locations in shorebird habitat to its availability within home ranges (local preference) and (3) relative use of roost sites. Concurrent with a 75% decrease in available shorebird habitat from early to late winter, average home range sizes increased by a factor of 3.8. At a regional scale, home ranges in early winter included a significantly greater percentage of shorebird foraging habitat than was available in the wider landscape. However, by late winter, the percent of shorebird habitat in home ranges did not match availability in the landscape. At the local scale, for both winter periods Dunlin were located in shorebird foraging habitat more often than expected given availability of habitat within home ranges [Correction added after online pub-lication 23 May 2008: sentence amended]. An increase in the number of roosts used from early to late winter implies possible reliance on additional sites in late winter for foraging opportunities. Results suggest that wet, unvegetated habitat is sought by Dunlin throughout winter, but individuals could not select home ranges in late winter that fully compensated for seasonal loss of habitat.     

Influence of Population Reduction on Predator Home Range Size and Spatial Overlap

ABSTRACT The increasing populations of red foxes (Vulpes vulpes), raccoons (Procyon lotor), and striped skunks (Mephitis mephitis) in the Intermountain West have contributed to low waterfowl recruitment in recent decades. This effect prompted the need for predator removal at many waterfowl refuges, such as the Bear River Migratory Bird Refuge (BRMBR) in the Great Salt Lake ecosystem. Our study examined the effects of the removal of predatory mammals at the BRMBR on the home range size and spatial overlap of the remaining populations of red foxes, raccoons, and striped skunks. The removal of predators through traps, snares, and night-shooting created a lower predator population during the predators' rearing and dispersal seasons. Predator removal did not result in a change of home range size for red foxes, raccoons, or striped skunks. In all species, home ranges were of similar size during the rearing and dispersal seasons and there were no differences among sexes. After predator removal, the proportion of a home range that overlapped with that of another conspecific decreased in foxes but increased in raccoons. However, predator removal did not change the proportion of inter-specific home range overlap between foxes and raccoons. These findings indicate that home range sizes of these mammalian predators were not constrained by their population densities prior to predator management. In this situation, predator control may be only temporarily successful in reducing predator populations. Managers may achieve more permanent reduction in predator population by decreasing food and shelter resources, thereby reducing the carrying capacity of the landscape.     

Population Status and Reproductive Success of an Endangered Epiphytic Orchid in a Fragmented Landscape

Habitat fragmentation and disturbance are two of the most significant drivers of species extinctions in plant populations. The degree of impact of fragmentation on plant populations depends on the level of specificity of plant–animal interactions, as well as on the availability of suitable sites for seedling recruitment. In this study, we describe the population density and structure, pollen limitation and reproductive success of the endangered tropical orchid Myrmecophila christinae, an epiphytic species with a specialized pollination system. We surveyed a total of 14 populations located in a fragmented landscape. Seedling density was related to habitat disturbance and host plant density; while density of juveniles was related to density of adults. Adult and total individual densities were related to habitat affectation. We also found that fragments <1 ha had significantly fewer seedlings, as well as an over‐representation of large adults. On the other hand, fruit production was higher in fragments >10 ha, and fruit set was significantly lower in highly disturbed fragments. Hand pollination experiments showed that M. christinae was pollen limited in all the studied populations, suggesting that pollen limitation is unrelated to habitat disturbance. Overall, our results suggest that fragmentation has affected key demographic features of M. christinae, including reproduction and recruitment.     

Spatial and Temporal Habitat Use Patterns by Water Birds in an Urban Estuarine Ecosystem: Implications for Ecosystem Management and Restoration

A quintessential urban estuary is the lower Passaic River in northeastern New Jersey, USA. This system is environmentally degraded and its ecosystem is functionally limited. Birds in this river are of particular interest for ecological assessment and environmental management because they are conspicuous, ecologically important, and their habitat requirements encompass the full range of ecosystems associated with the estuary. In this article, we present the results of a 1-year seasonal bird survey of the lower 6 miles of the Passaic River. We contrast our survey results with those from other waterways in the region that have stressor issues similar to the Passaic (i.e., contaminants, pathogens, physical disturbance, etc.), but which have substantially more wetlands habitat available for birds (i.e., fewer habitat constraints). Our objective was to evaluate the influence of habitat availability or constraints on bird use in such systems. The results of our survey and comparison to conditions of other regional waterways demonstrate that the lack of wetland and associated shoreline habitat in the lower Passaic River is likely the primary constraint on bird use of the system. Future investigations of individual stressors in this region should identify the habitat constraints in the decision matrix for judging management options.     

The behavioural ecology and population dynamics of a cryptic ground‐dwelling mammal in an urban Australian landscape

Urbanization results in widespread habitat loss and fragmentation and generally has a negative impact upon native wildlife, in particular ground‐dwelling mammals. The northern brown bandicoot (Isoodon macrourus; Marsupialia: Peramelidae) is one of relatively few native Australian ground‐dwelling mammals that is able to survive within urbanized landscapes. As a consequence of extensive clearing and urban development within the city of Brisbane, bandicoots are now restricted to the mostly small (<10 ha) bushland fragments scattered across the city landscape. Our study examined the behavioural ecology of northern brown bandicoots within habitat fragments located on a major creek‐line, using mark‐recapture population monitoring and radio telemetry. Bandicoots at monitored sites were found to occur at high densities (typically one individual ha^?1), although one‐third of the populations were transient. Radio tracking revealed that bandicoots had relatively small home ranges (mean 1.5 ± 0.2 ha) comprised largely of bushland/grassland with dense, often weed‐infested ground cover. Bandicoots sheltered by day in these densely covered areas and also spent most time foraging there at night, although they occasionally ventured small distances to forage in adjacent maintained parklands and residential lawns. We suggest that introduced tall grasses and other weeds contribute to high habitat quality within riparian habitat fragments and facilitate the persistence of high density populations, comprised of individuals with small home ranges. The generalized dietary and habitat requirements of northern brown bandicoots, as well as a high reproductive output, undoubtedly facilitate the survival of the species in urban habitat fragments. Further research is required on other native mammal species in urbanized landscapes to gain a greater understanding of how best to conserve wildlife in these heavily modified environments.     

Importance of matrix permeability and quantity of core habitat for persistence of a threatened saltmarsh bird

Species habitat preferences can be obscured when individuals have been recorded in non‐core habitats because of dispersal, spillover effects or spatial errors in observation locations. Disentangling the direct effects of the habitats species are observed in from the effects of proximity to other nearby habitats is especially challenging in fragmented landscapes, as many fragmentation metrics are correlated and it is difficult to prove independent effects. In this paper we addressed this issue by comparing a number of models based on predefined ecological theories. We compared models based on quantity of core habitat surrounding observations, proximity to core habitat, or a combination of the two to explain the observed distribution of the saltmarsh inhabiting white‐fronted chat (Epthianura albifrons) in coastal New South Wales, Australia. Proximity to core habitat was considered as either Euclidean distance or cost distance, and models were assessed using Akaike's information criterion and the area under the receiver operator characteristic curve on 10 random subsets of the data. We found that all models performed similarly, with the combination of cost distance and the quantity of saltmarsh performing better, but not significantly so. We compared the advantages and disadvantages of different models and also present a model averaged result. Our models suggested that the majority of saltmarshes in New South Wales were too small to have a large effect on probability of occurrence. As climate change is expected to further reduce the amount of available saltmarsh through continued mangrove incursion, coastal populations of the white‐fronted chat are expected to come under increasing threat. The conversion of grasslands to urban areas may also increase the effective distance between different populations of the species and reduce gene flow and rescue effects.     

Spatial ecology and conservation of the microendemic ovenbird Cipo Cinclodes (Cinclodes espinhacensis) from the Brazilian highlands

Birds in the genus Cinclodes are habitat specialists, with most restricted to the highlands of South America. The recently described Cipo Cinclodes (C. espinhacensis) is isolated in the southern Espinhaço Range of Brazil and is considered Endangered in Brazil and Near Threatened by the IUCN, but as a subspecies of Long‐tailed Cinclodes (C. pabsti). We examined the population and spatial ecology of Cipo Cinclodes at two geographic scales to improve our understanding of their basic biology and conservation status. We monitored 30 birds at Serra do Breu and found relatively large home ranges (mean = 9.3 ha), a density of paired adults of 0.09/ha, a male‐skewed adult sex ratio (males/total adults = 0.57) due to territories occupied by unpaired males, and long‐term site fidelity. Cipo Cinclodes used all habitat types available in our study area, including rocky outcrops, grasslands, and riparian areas, but habitat selection analyses revealed the importance of riparian areas for foraging and rocky outcrops for nesting. At the species distribution scale, we compiled known and novel recorded occurrence points and used them to calculate the extent of occurrence (EOO) and the area of occupancy (AOO). We used a Maxent species distribution model to generate a binary map to estimate upper limits for EOO (EOO around the model predicted area) and AOO (comprised by the model predicted area within the EOO). We obtained 41 locations, resulting in an EOO of 890.7 km² (up to 1748.7 km²) and an AOO of 100 km² (up to 327.5 km²). The global population is estimated to be between 880 and 2882 birds, which is concerning because small populations are at risk of extinction due to demographic stochasticity, genetic drift, and the interaction of these factors. As such, our results support the designation of Cipo Cinclodes as Endangered on the Brazilian red list.     

Population Structure and Ranging Patterns of <Emphasis Type="Italic">Rhinopithecus roxellana</Emphasis> in Zhouzhi National Nature Reserve,Shaanxi, China

We describe the population structure and ranging patterns of a troop of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) based on a study conducted between November 2002 and November 2003 in Zhouzhi National Nature Reserve, Shaanxi Province, China. The troop comprised several 1-male units and an all-male unit. Opportunistic censuses revealed that there were ≥112 individuals in the troop. The adult sex ratio (male vs. female) was 1:3.7. The ratios of adults to immatures and infants to adult females were 1:0.7 and 1:2, respectively. Via a grid system, we estimated the home range of the troop to be 18.3 km², of which 7.4 km² was the core area. The subjects exhibited distinct seasonal ranging patterns. Their movement across the home range was extensive in spring and restricted in autumn. In addition, reuse of quadrats was highest in winter and lowest in spring in comparison with other seasons. The daily path length (DPL) varied from .75 to 5 km, with a mean of 2.1 km. Seasonal analysis showed that DPL is significantly shorter in winter than in spring or summer; however, there is no significant difference between the DPLs of spring and summer or those of spring and autumn. The monkeys occupied elevations 1500–2600 m above sea level; the annual mean of altitudinal range is 2137 m. Contrary to early studies that reported Rhinopithecus roxellana migrates to lower elevations in winter, we found no evidence supporting a seasonal altitudinal shift. Using the highest troop count and home range estimate, and considering the extent of range overlap between neighboring troops, we calculated the population density and biomass of Rhinopithecus roxellana to be 7.2 individuals/km² and 68.3 kg/km², respectively. The temporal and spatial distribution of food resources may be the most important determinant of ranging behavior in Rhinopithecus roxellana, though understanding the relationship between resource distribution and seasonal range use may require further investigation.