The value of countryside elements in the conservation of a threatened arboreal marsupial Petaurus norfolcensis in agricultural landscapes of South-Eastern Australia—the disproportional value of scattered trees

Human activities, particularly agriculture, have transformed much of the world's terrestrial environment. Within these anthropogenic landscapes, a variety of relictual and semi-natural habitats exist, which we term countryside elements. The habitat value of countryside elements (hereafter termed 'elements') is increasingly recognised. We quantify the relative value of four kinds of such 'elements' (linear roadside remnants, native vegetation patches, scattered trees and tree plantings) used by a threatened Australian arboreal marsupial, the squirrel glider (Petaurus norfolcensis). We examined relationships between home range size and the availability of each 'element' and whether the usage was relative to predicted levels of use. The use of 'elements' by gliders was largely explained by their availability, but there was a preference for native vegetation patches and scattered trees. We found home range size was significantly smaller with increasing area of scattered trees and a contrasting effect with increasing area of linear roadside remnants or native vegetation patches. Our work showed that each 'element' was used and as such had a role in the conservation of the squirrel glider, but their relative value varied. We illustrate the need to assess the conservation value of countryside elements so they can be incorporated into the holistic management of agricultural landscapes. This work demonstrates the disproportional value of scattered trees, underscoring the need to specifically incorporate and/or enhance the protection and recruitment of scattered trees in biodiversity conservation policy and management

Marsupial response to matrix conversion: Results of a large-scale long-term 'natural experiment' in Australia

We quantified changes in forest-dependent mammal populations when the habitat in which they live remains intact but the surrounding matrix is converted from open grazed land to closed pine plantation forest. This situation is increasingly common as plantations are often established on formerly cultivated or grazed land.We conducted a large-scale (30km2), long-term (14years) fully controlled and replicated (111 sites) 'natural experiment' in south-eastern Australia. The study focused on the effects of changes occurring in the matrix on mammals which inhabit patches of native Eucalyptus woodland.We found that none of the five target species in our study (two macropods, two possums and a glider) responded negatively to pine plantation establishment. For three species (the sugar glider Petaurus breviceps, the red necked wallaby Macropus rufogriseus and the swamp wallaby Wallabia bicolor) the response to plantation establishment was positive (i.e., increase in colonisation/patch use in sites surrounded by pine plantations) whereas the two possums (the common ringtail possum Pseudocheirus peregrinus and the common brushtail possum Trichosurus vulpecula) were positively affected by the amount of native tree cover surrounding sites, rather than pine plantation establishment.We foresee two strong implications of our work for the conservation of mammal species in agricultural areas subject to multiple land-use changes: 1) Our results suggest that converting agricultural land to pine plantations will not affect our target mammalian species negatively; rather, it may facilitate colonisation of remnant patches of native vegetation by some species. 2) Our findings underscore the critical importance of preserving remnant native vegetation within plantations, as it may decrease the risk of local extinction for some species or facilitate the colonisation of new sites for others. Thus, retention of patches of remnant native vegetation should be part of the design of future plantations

Do nest boxes in restored woodlands promote the conservation of hollow-dependent fauna?

Vegetation restoration is considered an important strategy for reversing biodiversity decline in agricultural areas. However, revegetated areas often lack key vegetation attributes like large old hollow-bearing trees. As these trees take a long time to develop, artificial cavities such as nest boxes are sometimes provided to address lag effects. We conducted a 3-year experiment using 150 nest boxes with four designs to quantify patterns of occupancy within 16 replanted areas and 14 patches of remnant old growth eucalypt woodland. We quantified patterns of occupancy of nest boxes in physically connected versus isolated remnants and plantings, and multiple covariate effects on nest box occupancy at the nest box, tree, patch and landscape levels. Our analyses revealed a lower probability of nest box occupancy within remnants (versus plantings) for two of the six response variables examined: any species, and the Feral Honeybee. Nest boxes in connected remnants and plantings were more likely to be occupied than those in isolated plantings and remnants by any mammal and the Common Brushtail Possum. Nest boxes in restored woodlands are used by some hollow-dependent fauna, but principally already common species, and not taxa of conservation concern. Nest boxes also were used by pest species. A key management consideration must be to create connected habitat to facilitate colonization of nest boxes by mammals. Approximately 15% of the cavity-dependent vertebrates within the study area used next boxes, possibly because the diverse requirements of the array of other species were not met by the range of nest boxes deployed

How does a transforming landscape influence bird breeding success?

Context The conversion of agricultural landscapes to tree plantations is a major form of landscape transformation worldwide, but its effects on biodiversity, particularly key population processes like reproductive success, are poorly understood. Objectives We compared bird breeding success between woodland remnants surrounded by maturing stands of plantation Radiata Pine and a matched set of woodland remnants in semi-cleared grazing land. Methods Our study was conducted in the Nanangroe region in south-eastern New South Wales, Australia. Using repeated field measurements, we quantified bird breeding success in 23 woodland remnants; 13 surrounded by Radiata Pine plantations and 10 on farms where remnants were surrounded by semi-cleared grazing land. We matched the attributes of native remnant patches between two types of matrix. Results We found that: (1) rates of nesting success of smaller-bodied birds in woodland remnants surrounded by grazing land were significantly higher than in woodland remnants surrounded by pine plantations; and (2) taxa with domed nests were more successful at nesting than species that constructed open cup/bowl nests in woodland remnants within farmlands. Conclusions Our findings suggest that bird breeding success in remnant woodland patches is significantly diminished as a result of the conversion of semi-cleared grazing land to pine plantations

Birds as surrogates for mammals and reptiles: Are patterns of cross-taxonomic associations stable over time in a human-modified landscape?

Cross-taxonomic surrogates can be feasible alternatives to direct measurements of biodiversity in conservation if validated with robust data and used with explicit goals. However, few studies of cross-taxonomic surrogates have examined how temporal changes in composition or richness in one taxon can drive variation in concordant patterns of diversity in another taxon, particularly in a dynamic and heavily modified landscape. We examined this problem by assessing changes in cross-taxonomic associations over time between the surrogate (birds) and target vertebrate taxa (mammals, reptiles) that demand high sampling effort, in a heterogeneous mosaic landscape comprising pine monoculture, eucalypt woodland remnants and agricultural land. Focussing on four study years (1999, 2001, 2011, 2013) from a dataset spanning 15 years, we: (1) investigated temporal changes in cross-taxonomic congruency among three animal taxa, (2) explored how temporal variation in composition and species richness of each taxon might account for variation in cross-taxonomic congruency, and (3) identified habitat structural variables that are strongly correlated with species composition of each taxon. We found the strength of cross-taxonomic congruency varied between taxa in response to both landscape context and over time. Among the three taxa, overall correlations were weak but were consistently positive and strongest between birds and mammals, while correlations involving reptiles were usually weak and negative. We also found that stronger species richness and composition correlations between birds and mammals were not only more prevalent in woodland remnants in the agricultural matrix, but they also increased in strength over time. Temporal shifts in species composition differed in rate and extent among the taxa even though these changes were significant over time, while important habitat structural correlates were seldom shared across taxa. Our study highlights the role of the landscape matrix and time in shaping animal communities and the resulting cross-taxonomic associations in the woodland remnants, especially after a major perturbation event (i.e. plantation establishment). In such dynamic landscapes, differing and taxon-specific shifts in diversity over time can influence the strength, direction and consistency of cross-taxonomic correlations, therefore posing a �temporal� problem for the use of surrogates like birds in monitoring and assessments of biodiversity, and conservation management practices.Lesslie Foundation; Australian Research Council Laureate Fellowship

The vacant planting: limited influence of habitat restoration on patch colonization patterns by arboreal marsupials in south-eastern Australia

Many key questions remain unresolved about how biodiversity responds to temporal increases in native vegetation cover resulting from extensive restoration efforts. We quantified occupancy and colonization probability of old growth, regrowth and planted woodland patches by arboreal marsupials within Australian agricultural landscapes subject to woodland restoration over an 11 year period. Our analyses focussed on the Common Brushtail Possum (Trichosurus vulpecula) and Common Ringtail Possum (Pseudocheirus peregrinus). We found strong evidence of a gradient in occupancy levels ranging from highest in old growth woodland, approaching zero in plantings, with regrowth woodland intermediate between these two broad types of vegetation structure. Plantings were not occupied by either species at the outset of our investigation and were rarely colonized throughout the subsequent 10 years. We hypothesize that a lack of shelter sites in large old hollow-bearing trees is one of the key factors limiting the occurrence of plantings by cavitydependent arboreal marsupials, suggesting a lag between planting establishment and the time required for plantings to become suitable habitat. We found the probability of colonization was positively related to the amount of vegetation cover in the surrounding landscape. Unexpectedly, colonization probability was not influenced by a temporal increase in woody vegetation cover surrounding a patch. A paucity of relationships between patch colonization and the temporal change in vegetation cover may be explained by the fact that most of the increased vegetation cover in our study landscapes over the past decade has resulted from establishment of plantings which are generally not suitable nesting habitat for arboreal marsupials. Our findings have key management implications such as emphasizing the value of old growth woodland for arboreal marsupials and of targeting restoration efforts around old growth and regrowth woodland patches, and the flawed notion of biodiversity offsets that allow replantings to compensate for clearing old growth woodland.Murray Local land Services, the Riverina Local Land Services, the Australian Research Council, and the Australian Government (National Environmental Science Program)

The supermassive black hole of M87 and the kinematics of its associated gaseous disk

We have obtained long-slit observations of the circumnuclear region of M87 at three different locations, with a spatial sampling of 0.028" using the Faint Object Camera f/48 spectrograph on board HST. These data allow us to determine the rotation curve of the inner ~1" of the ionized gas disk in [OII]3727 to a distance as close as 0.07" (~5pc) to the dynamic center, thereby significantly improving on both the spatial resolution and coverage of previous FOS observations. We have modeled the kinematics of the gas under the assumption of the existence of both a central black hole and an extended central mass distribution, taking into account the effects of the instrumental PSF, the intrinsic luminosity distribution of the line, and the finite size of the slit. We find that the central mass must be concentrated within a sphere whose maximum radius is 0.05" (~3.5pc) and show that both the observed rotation curve and line profiles are consistent with a thin--disk in keplerian motion. We conclude that the most likely explanation for the observed motions is the presence of a supermassive black hole and derive a value of M_{BH} = (3.2+/-0.9) 10^9 M_{sun} for its mass

Magellanic Cloud X-ray Sources: III. Completion of a ROSAT Survey

This paper concludes a series of three papers presenting ROSAT High-Resolution Imager (HRI) observations of unidentified Einstein and serendipitous ROSAT X-ray sources in the direction of the Magellanic Clouds. Accurate positions and fluxes have been measured for these sources. Optical photometry and spectroscopy were obtained to search for identifications in order to determine the physical nature of these sources. The present paper includes new data for 24 objects; identifications are given or confirmed for 30 sources. For six sources optical finding charts showing the X-ray positions are provided. The results from this program are summarized, showing the populations of luminous X-ray sources in the Magellanic Clouds are quite different from those in the Galaxy.Comment: 28 pages, 2 figures; to appear in Astronomical Journa

Not All Kinds of Revegetation Are Created Equal: Revegetation Type Influences Bird Assemblages in Threatened Australian Woodland Ecosystems

The value for biodiversity of large intact areas of native vegetation is well established. The biodiversity value of regrowth vegetation is also increasingly recognised worldwide. However, there can be different kinds of revegetation that have different origins. Are there differences in the richness and composition of biotic communities in different kinds of revegetation? The answer remains unknown or poorly known in many ecosystems. We examined the conservation value of different kinds of revegetation through a comparative study of birds in 193 sites surveyed over ten years in four growth types located in semi-cleared agricultural areas of south-eastern Australia. These growth types were resprout regrowth, seedling regrowth, plantings, and old growth