Gotowa bibliografia na temat „Kaitorete Spit”

Context. The process of urban sprawl brings the human population and their domestic cats (Felis catus) in close contact with wildlife in areas that were previously remote, including reserves and conservation areas created to protect populations of vulnerable or threatened species. Various mitigation measures have been proposed, including devices designed to hinder cat hunting ability, desexing to reduce wandering and nuisance behaviours, containment at night or at all times and regulations governing cat ownership. Such regulations may aim to reduce cat densities by limiting the number of cats per household, or they may define zones around sensitive conservation areas where cat ownership is prohibited. Aims. The present study sought to establish the necessary size of cat-exclusion zones in rural and urban-fringe landscapes where vulnerable prey species may also reside. Methods. With GPS collars, we tracked 38 domestic cats at three sites (one rural, two urban fringe) where small reserves contained threatened lizard species. Key results. Home ranges (95% kernel density estimates) were considerably larger for cats at the rural site (0.3–69 ha) than at urban-fringe sites (0.35–19 ha at Kaitorete Spit and 0.2–9 ha at Otago Peninsula), and were larger at night than day. Resource selection ratios indicated avoidance of open areas with little cover, such as cultivated areas (farmland), tussock grassland and duneland, whereas sources of cover such as trees and buildings were preferred. Maximum distances moved and large variability between individual cats suggest buffers in rural landscapes would need to be at least 2.4 km wide, whereas those in urban-fringe habitat could be half as large. Conclusions. Despite significant home-range size differences exhibited by cats living in rural v. urban-fringe habitats, exclusion zones would need to be wide to account for considerable inter-cat variation in movement behaviour. Implications. The size of an effective cat-exclusion zone should represent the specific landscape, amount of residential development and substantial variability between individual cats.

Baited pitfall traps were used to sample the lizard fauna at Birdlings Flat on Kaitorete Spit, Canterbury. Four species had been recorded previously from this area; Leiolopisma maccanni Patterson and Daugherty, Leiolopisma nigriplantare polychroma Patterson and Daugherty, Leiolopisma lineoocellatum (Dumeril and Dumeril) and Hoplodactylus maculatus (Gray). Three of these species (L. maccanni, L. n. polychroma and H. maculatus) were captured during the course of the study. The aim of this present study was to examine the nature of the ecological relationship among these three species at Birdlings Flat. Capture data indicated that L. maccanni was almost entirely confined to the dunelands while L. n. polychroma was associated exclusively with shrublands on old dune ridges behind the sand dunes. H. maculatus' distribution encompassed both of these major habitats. Separation on the basis of habitat was thought to be the most important niche variable for these two diurnal skinks. There was some temporal separation in activity of these two species, with L. maccanni active earlier in the day than L. n. polychroma. However, there was a high degree of overlap in the activity periods of these two species. Temporal differentiation between the nocturnal gecko H. maculatus and the two diurnal skinks is thought to be an important means by which these species coexist. The most common prey items consumed by all three species were Diptera, Araneae, C. propinqua seeds, Hemiptera, unidentified arthropod eggs, Coleoptera and Hymenoptera. Dietary differences between the two skink species were apparent although these differences appeared to be related to the preferred habitats of the respective species. Density estimates for L. maccanni varied between 1050/ha and 1850/ha while L. n. polychroma density varied between 200/ha and 400/ha. The density of H. maculatus was not calculated but appeared to be intermediate to the density of the two skink species. The apparent disappearance of L. lineoocellatum from an area where they were once relatively common is cause for concern. There is no obvious reason for this decline although it may be related to the combined impacts of predation, collection and habitat disturbance.

Baited pitfall traps were used to sample the lizard fauna at Birdlings Flat on Kaitorete Spit, Canterbury. Four species had been recorded previously from this area; Leiolopisma maccanni Patterson and Daugherty, Leiolopisma nigriplantare polychroma Patterson and Daugherty, Leiolopisma lineoocellatum (Dumeril and Dumeril) and Hoplodactylus maculatus (Gray). Three of these species (L. maccanni, L. n. polychroma and H. maculatus) were captured during the course of the study. The aim of this present study was to examine the nature of the ecological relationship among these three species at Birdlings Flat. Capture data indicated that L. maccanni was almost entirely confined to the dunelands while L. n. polychroma was associated exclusively with shrublands on old dune ridges behind the sand dunes. H. maculatus' distribution encompassed both of these major habitats. Separation on the basis of habitat was thought to be the most important niche variable for these two diurnal skinks. There was some temporal separation in activity of these two species, with L. maccanni active earlier in the day than L. n. polychroma. However, there was a high degree of overlap in the activity periods of these two species. Temporal differentiation between the nocturnal gecko H. maculatus and the two diurnal skinks is thought to be an important means by which these species coexist. The most common prey items consumed by all three species were Diptera, Araneae, C. propinqua seeds, Hemiptera, unidentified arthropod eggs, Coleoptera and Hymenoptera. Dietary differences between the two skink species were apparent although these differences appeared to be related to the preferred habitats of the respective species. Density estimates for L. maccanni varied between 1050/ha and 1850/ha while L. n. polychroma density varied between 200/ha and 400/ha. The density of H. maculatus was not calculated but appeared to be intermediate to the density of the two skink species. The apparent disappearance of L. lineoocellatum from an area where they were once relatively common is cause for concern. There is no obvious reason for this decline although it may be related to the combined impacts of predation, collection and habitat disturbance.

Kaitorete Spit is a mixed sand and gravel barrier beach complex that is located at the northeastern end of the Canterbury Bight. Kaitorete Spit was examined during this study using a combination of ground penetrating radar surveys, sedimentological and geomorphological examinations of the barrier beach complex. The geomorphology formed on Kaitorete has developed in three different environments. At the northeastern end of Kaitorete low elevation spit recurves are formed. South of these are numerous parallel beach ridges, formed by the tops of prograded storm berms. Lacustrine geomorphic features have developed over the marine geomorphology. Small scale cuspate ridges have formed in shallow lake water and associated with lake bottom sediments. Lacustrine beach ridges, lacustrine beach ridge plains and lacustrine spit complexes all formed along the shore of a higher lake. Nine different radar facies were found developed in the radar profiles collected on Kaitorete Spit. The facies are defined on the basis of their internal reflector patterns. Generally, the reflector patterns could be predicted by interpreting the geomorphic features over which the radar profiles ran. Three of the radar facies revealed reflector patterns that could not be predicted using geomorphology alone. At the eastern end of Kaitorete Spit, the radar profiles revealed that the marine spit recurves comprise a spit beach overlying a spit platform. It also reveals that the distal end of the spit platform was reworked by tidal currents into a series of seaward prograding foresets. The radar profiles also revealed that immediately the barrier beach reached the edge of the spit platform, a rise in the elevation of the beach crest occurred due to an increase in the wave energy expended on the beach. In the centre of the barrier beach complex the radar profiles revealed that two long overwash barriers developed, which fill two long (up to 12 km), thin lake outlet lagoons. These lagoons developed as a result of breaching due to a large river overfilling the lake basin. After the initial breach, the longshore drift and lake outflow developed a dynamic equilibrium, resulting in the progressive eastward dislocation of the outlet mouth. The large volume of lake water acted to buffer the high flows of the river thereby, maintaining flow conditions at the outlet channel which were conducive to lagoon elongation. Associated with the lacustrine spit complexes are scarp-like ridges which have steep reflectors which dip away from the lake. These developed in a similar way to shore-parallel bars, with material moving up the stoss side and avalanching down the lee side. The combined application of ground penetrating radar and geomorphology reveals a much more complete geological history of an area where outcrop is sparse.

Artificial retreats are increasingly used to sample animal populations and in attempts to boost animal numbers in degraded habitats. Here, I test potential applications of artificial retreats for lizards inhabiting a coastal environment of high conservation value (Kaitorete Spit, New Zealand). I first conducted a pitfall-trapping survey examining the distribution and relative abundance of lizards in duneland, farmland and shrubland habitats, and tested the influence of trap placement on capture rates. Capture rates of the diurnal skinks Oligosoma maccanni (McCann�s skink) and O. nigriplantare polychroma (common skink) were highest in duneland and farmland, respectively, and were most sensitive to the distance separating traps from the nearest cover (the greater the distance, the lower the capture rate). Captures of O. lineoocellatum (spotted skink) and Hoplodactylus maculatus (common gecko) were rare. Secondly, in separate chapters I test the utility of artificial retreats for monitoring: 1) a preference trial examining relative use of three types of artificial retreats by skinks (O. maccanni and O. n. polychroma) and geckos (H. maculatus); 2) a comparison of the effectiveness of artificial retreats relative to pitfall traps for detecting cryptic and primarily nocturnal geckos (H. maculatus) following translocation; and 3) capture-recapture estimation of population parameters (survival and abundance) of H. maculatus. I found that: 1) geckos strongly preferred retreats made of Onduline over corrugated iron and concrete tiles, whereas skinks exhibited no apparent preferences; 2) artificial retreats were more effective than pitfall traps for detecting geckos following translocation; and 3) monthly survival and recapture probabilities of geckos varied with age-class and over time. Estimated survival was unexpectedly low, possibly due to excessive trap spacing. I developed a new capture-recapture model specifically for population size estimation with data from artificial retreats, which gave estimates that were up to 50% greater than those predicted by conventional capture-recapture models. I caution that permanent placement of artificial retreats in long-term studies may be inappropriate for estimation of population parameters due to potential habitat-enhancement effects and/or altered predation risk. Thirdly, I conducted a capture-recapture field experiment, using a replicated Before-After-Control-impact (BACI) design, to test the relative effects of habitat manipulation (artificial retreat addition) and partial predator removal (by fencing) on annual survival of duneland skink (O. maccanni) populations. Survival increased at sites with predator exclosures, but not at control sites or following the addition of artificial retreats, either alone or in combination with a predator exclosure. The magnitude of the increase in survival for the exclosure-only treatment was small, but sufficient to change the trajectory of an apparently stable population into an increasing one, suggesting that the population is limited by predators. Predator control, but not the addition of artificial retreats, is predicted to benefit O. maccanni. To conclude, the Onduline design developed here appears to be particularly useful for sampling cryptic, terrestrial geckos; however, artificial retreats must be used appropriately to avoid bias arising from habitat-enhancing effects and/or altered predation risk. The restoration value of artificial retreats requires further testing on other species and in areas where natural retreat sites are limited.