Site Occupancy Patterns Research Articles

Site occupancy of native terrestrial mammals in oil palm landscapes is driven by the synergy of land sparing and sharing strategies

The conversion of tropical rainforests into industrial oil palm monocultures has detrimental effects of local biodiversity. Although some medium-sized mammals have demonstrated a degree of adaptability in oil palm landscapes, the factors that influence their ability to persist in such human-altered environments remain obscure. Here, we investigated the site occupancy and activity pattern of the mammals in oil palm landscapes in Peninsular Malaysia. We deployed 81 camera traps throughout six oil palm cultivation areas with two distinct management styles (three sites each in organized smallholdings and industrial plantations). Smallholdings had higher site occupancy of native animal species than industrial plantations. The site occupancy of the mammals was influenced by the proximity to continuous forest, forest patches and riparian vegetation. Landscape metrics are characteristics that affect land sparing strategy, allowing wildanimals in agricultural landscapes to thrive in their habitat despite human threats. At stand-level, the detection of animals was determined by elevation, undergrowth vegetation cover/height, canopy cover, oil palm height, quantity of oil palm fruits, and prune stack thickness. Mammal occupancy was higher in the smallholdings due to the proximity to continuous forest. We recommend improving landscape heterogeneity and connectivity in oil palm matrix to promote species mobility and diversifying oil palm management away from monoculture farming. Our findings indicate that incorporating land sharing and sparing strategies into the oil palm matrix is necessary to conserve biodiversity and maintain ecological services. This implies that industry stakeholders ought not to disregard either land sparing or land sharing.

Atomic distributions of Ag and In in the γ-brass type Ag9In4

The γ-brass type phase Ag9In4 in the binary Ag–In system has been synthesized by high-temperature method and, the crystal structure has been determined by the means of X-ray diffraction techniques and energy dispersive X-ray spectroscopy. The structure crystallizes in the primitive cubic space group P4‾3m (cP52) with a cell parameter of ∼ 9.89 Å. The unit cell contains 52 atoms distributed over 8 crystallographically independent positions. Due to weak X-ray scattering contrast between Ag and In, first principle DFT calculations have been carried out to determine the accurate site occupancy pattern of Ag and In in the structure of Ag9In4. The structure can be viewed in terms of two symmetrically inequivalent 26-atom γ-clusters (Ag22In4 and Ag14In12). The density of state (DOS) curve shows a pseudogap near the Fermi level, which endorses the phase stability by Hume-Rothery mechanism due to interaction between the Fermi surface and the Brillouin zone (FS-BZ). Bonding analysis shows that Ag–In contact has the highest contribution in stabilizing the titled phase.

γ-Brass type structures with I- and P-cell in the ternary Cu–Zn–In system

Abstract γ-Brass type phases in Cu–Zn–In ternary system were synthesized from the highly pure elements by conventional solid-state synthesis and characterized by X-ray diffraction and EDX analysis. Diffraction analysis confirmed the existence of cubic γ-brass type phases with I- and P-cell having a significant homogeneity range in the ternary Cu–Zn–In system. The phase homogeneity is connected with structural disorder based on mixed site occupancies. Site specific In substitution was observed during single-crystal structure analysis. The γ-brass structures with body-centered cubic lattice (I 4 ‾ $‾{4}$ 3m) are viewed as 26-atom γ-clusters. Like Cu5Zn8, the inner tetrahedron (IT), outer tetrahedron (OT) and octahedron (OH) sites in the 26-atom clusters of γ-brass structures with I-cell are occupied by Zn, Cu, Cu, respectively. Indium substitution is restricted to the cuboctahedral (CO) site and the CO site is assumed to be mixed with In, Cu and Zn throughout the homogeneity range. The structures of cubic γ-brass type (P 4 ‾ $‾{4}$ 3m) phases with P-cell are built up with two independent 26‐atom γ‐clusters and centered at the special positions A (0, 0, 0) and B (½, ½, ½) of the unit cell. According to the single‐crystal X‐ray analyses, In substitutions are largely restricted to the cuboctahedral sited B clusters. In the cubic γ-phases with P-cell, site occupancy pattern of cluster positioned at A is similar to the γ-cluster in Cu5Zn8, whereas cluster B bears a close resemblance to Cu-poor γ-cluster (Cu14In12) of Cu9In4 (P 4 ‾ $‾{4}$ 3m). The vec values for cubic γ-brass type phases in the Cu–Zn–In ternary system ranges between 1.57 and 1.64.

Patterns of Monarch Site Occupancy and Dynamics in Iowa

The monarch butterfly (Danaus plexippus) is the focus of large-scale habitat restoration efforts because of recent population declines. From 2006-2017 we monitored monarchs at >400 sites throughout Iowa to link site occupancy and colonization/extinction dynamics to the presence of milkweed, site-specific habitat metrics, and landscape context at differing spatial scales. We used a robust design occupancy model in Program MARK and a hierarchical model selection approach to estimate site occupancy, extinction and colonization probabilities, and detection probability. Occupancy models revealed that monarchs responded differently to landscape features, environmental conditions, and local habitat conditions for site occupancy, extinction, and colonization probabilities. For site occupancy, the mean patch size of grassland at the 1-km spatial scale had a positive effect (β_GrassPS1K= 0.94, SE = 0.54) while the percent of the landscape in woodland at the 200-m spatial scale had a negative effect (β_WoodPL200= -1.68, SE = 0.34). For extinction, there were additive effects of the percent of the landscape in woodland at the 100-m spatial scale (β_WoodPLAND100= 2.70, SE = 0.63), the interspersion of grassland at the 1-km spatial scale (β_GrassIJI1K= -2.30, SE = 0.63), and litter depth (β_Litter= 0.46, SE = 0.13). Finally, there were negative effects of the percent of the landscape in woodland at the 200-m spatial scale (β_WoodPLAND200= -4.67, SE = 1.37) and the interspersion of grassland at the 100-m spatial scale (β_GrassPS1K= -2.02, SE = 0.70) on colonization probability. Detection probability was affected by the additive effects of canopy cover and monarch density; no other detection model was competitive. In the top model there was a positive effect of monarch density (β_Density = 0.28, SE = 0.05) and a negative effect of canopy cover (β_Canopy=-0.18, SE = 0.03) on detection probability. In Iowa, monarchs are widespread on conservation lands where they avoid sites with lots of canopy cover. Colonization and extinction processes are influenced by an interplay of landscape attributes across multiple spatial scales and site habitat attributes. Our study provides the first comprehensive insight into monarch use of conservation lands in Iowa, and predicted responses to important covariates may be useful for future conservation efforts.

Monod-Wyman-Changeux Allosteric Shift Analysis in Mutant α1β3γ2L GABAA Receptors Indicates Selectivity and Crosstalk among Intersubunit Transmembrane Anesthetic Sites.

Propofol, etomidate, and barbiturate anesthetics are allosteric coagonists at pentameric α1β3γ2 GABAA receptors, modulating channel activation via four biochemically established intersubunit transmembrane pockets. Etomidate selectively occupies the two β +/α - pockets, the barbiturate photolabel R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (R-mTFD-MPAB) occupies homologous α +/β - and γ +/β - pockets, and propofol occupies all four. Functional studies of mutations at M2-15' or M3-36' loci abutting these pockets provide conflicting results regarding their relative contributions to propofol modulation. We electrophysiologically measured GABA-dependent channel activation in α1β3γ2L or receptors with single M2-15' (α1S270I, β3N265M, and γ2S280W) or M3-36' (α1A291W, β3M286W, and γ2S301W) mutations, in the absence and presence of equipotent clinical range concentrations of etomidate, R-mTFD-MPAB, and propofol. Estimated open probabilities were calculated and analyzed using global two-state Monod-Wyman-Changeux models to derive log(d) parameters proportional to anesthetic-induced channel modulating energies (where d is the allosteric anesthetic shift factor). All mutations reduced the log(d) values for anesthetics occupying both abutting and nonabutting pockets. The Δlog(d) values [log(d, mutant) - log(d, wild type)] for M2-15' mutations abutting an anesthetic's biochemically established binding sites were consistently larger than the Δlog(d) values for nonabutting mutations, although this was not true for the M3-36' mutant Δlog(d) values. The sums of the anesthetic-associated Δlog(d) values for sets of M2-15' or M3-36' mutations were all much larger than the wild-type log(d) values. Mutant Δlog(d) values qualitatively reflect anesthetic site occupancy patterns. However, the lack of Δlog(d) additivity undermines quantitative comparisons of distinct site contributions to anesthetic modulation because the mutations impaired both abutting anesthetic binding effects and positive cooperativity between anesthetic binding sites.

Boundary constraints on population dynamics in a percolating habitat

The spatial distribution of suitable environmental conditions defines a species habitat, and colonization-extinction dynamics within this habitat determine the distribution of species populations. In addition, the success of colonization and the risk of extinction are expected to be influenced by the proximity to habitat boundary. We address here the influence of boundary vicinity for a contact-process model of population dynamics in a percolating habitat lattice. To separate the influence of boundary vicinity from that of fragment area, we investigate population dynamics in the very large spanning cluster of the percolating habitat. The geometry of the spanning cluster varies when habitat density in the lattice is tuned away from the percolation threshold. We expect that the colonization success decreases closer to the boundary, leading to depleted site occupancy in the cluster, and that this effect is even more pronounced near the extinction threshold of the contact process. For the set of suitable sites of the cluster and unsuitable sites next to its boundary, we quantify the boundary density, σ, as the probability to draw a pair of suitable and unsuitable sites. The cluster boundary is most rugged and σ is maximal close to the percolation threshold of the habitat. We expect that the global influence of boundary on population dynamics in the cluster is greater when the boundary is more rugged. We thus investigate population dynamics in the spanning cluster for varying values of σ. We determine the stationary properties of population dynamics in the spanning cluster according to σ and to the species-specific ratio of extinction and colonization rates, denoted r. Using both numerical simulations and a pair-approximation model, we assess global species persistence and site occupancy patterns in the spanning cluster. We show that the extinction threshold rc depends crucially on σ, i.e., increasing σ limits global species persistence. Furthermore, increasing σ decreases the probability of site occupancy in the spanning cluster. A key result is that this influence extends to sites far from the boundary when r gets close to rc. Therefore, species that are at risk of extinction are more sensitive to the influence of habitat boundary. These results are of both theoretical and practical interest for understanding and forecasting species viability in heterogeneous and fragmented habitats.

Site Occupancies and Their Effects on the Physical Properties of Spinel : An Ab Initio Study

Recent experiments on Fe substituted spinel CoCr2O4 have discovered multiple functional properties in the system such as temperature and composition dependent magnetic compensation, and tunable exchange bias. These properties are attributed to the renormalization of the inter‐atomic magnetic exchange interactions arising due to the non‐regular site occupancies of the magnetic cations. We perform ab initio electronic structure calculations by DFT + U method and combine with a generalized thermodynamic model to compute the site occupancy patterns of magnetic cations, structural properties and magnetic exchange interactions of CoO4 for the entire composition range 0 < x < 1. We find that the substituting Fe atoms prefer to occupy the tetrahedral sites of the spinel structure for the entire range of , in agreement with the experimental inferences. By computing the variations of the various inter‐atomic magnetic exchange interactions as a function of site occupancy, we provide a microscopic picture of the evolution of a collinear structure from a non‐collinear one due to substitution of Fe in CoCr2O4. The computed results are analyzed using the electronic structures. This work is a systematic study exploring the interrelations of site occupancy, composition, electronic structure and magnetic interactions in Fe‐substituted CoCr2O4 which helps gain fundamental knowledge of this material.

Boreal small mammals show evidence of density-dependent patterns with area-sensitivity

In recent years, habitat amount in fragmented landscapes has been shown to positively influence population size, species occurrence, and species diversity. Quantifying how sensitive bioindicator species respond to the amount of habitat in disturbed landscapes (i.e. area-sensitivity) has become a growing research focus to provide robust guidelines for ecosystem-based management. In this study, we modelled the occurrence of North American boreal small mammals in relation with the total amount of forest surrounding remnant forest patches in disturbed landscapes while controlling for local habitat associations. Over the summers of 2013 and 2014, we conducted four trapping sessions in 60 sites located in old forest remnant patches of old forests in both wildfires and aggregated clearcuts, and in continuous old forest blocks within the black spruce forest of northwestern Quebec, Canada. American red squirrels (Tamiasciurus hudsonicus), southern red-backed voles (Myodes gapperi) and masked shrews (Sorex cinereus) represented 85.5% of our total captures. We measured the amount of habitat (percentage of forest cover) within 100 concentric buffers around each capture grid using digital forest cover maps. Buffers varied in radii from 50m to 5km. We quantified area-sensitivity using dynamic models of single-species occupancy to estimate the probabilities of initial site occupancy, site extinction and site colonisation of each species according to both local habitat variables and surrounding habitat amount. We found no associations between initial site occupancy, site colonisation, or site extinction with local habitat features, possibly in response to habitat structure similarity of our three site types. Species studied had different life histories in terms of population dynamics' and timing of juvenile dispersal, possibly explaining why each species had its individual response to the amount of habitat in the surrounding landscape. For the American red squirrel, we found no evidence of within-year area-sensitivity on initial site occupancy patterns, whereas negative area sensitivity on initial site occupancy between-years was observed for the southern red-backed vole. In contrast, we found positive area-sensitivity on between-years site colonisation for this latter species at small spatial scales. For masked shrews, we detected negative area-sensitivity on initial site occupancy within-year. As populations were sampled at low density, we suspect that the sparse distribution of individuals may influence area-sensitivity patterns. Future studies should consider area-sensitivity with regards to both spatial and temporal scales. We encourage long-term monitoring of animal populations at multiple spatial scales to investigate the underlying ecological mechanisms of positive and negative area-sensitivity.

Relationships between gas field development and the presence and abundance of pygmy rabbits in southwestern Wyoming

AbstractMore than 5957 km2 in southwestern Wyoming is currently covered by operational gas fields, and further development is projected through 2030. Gas fields fragment landscapes through conversion of native vegetation to roads, well pads, pipeline corridors, and other infrastructure elements. The sagebrush steppe landscape where most of this development is occurring harbors 24 sagebrush‐associated species of greatest conservation need, but the effects of gas energy development on most of these species are unknown. Pygmy rabbits (Brachylagus idahoensis) are one such species. In 2011, we began collecting three years of survey data to examine the relationship between gas field development density and pygmy rabbit site occupancy patterns on four major Wyoming gas fields (Continental Divide–Creston–Blue Gap, Jonah, Moxa Arch, Pinedale Anticline Project Area). We surveyed 120 plots across four gas fields, with plots distributed across the density gradient of gas well pads on each field. In a 1 km radius around the center of each plot, we measured the area covered by each of 10 gas field infrastructure elements and by shrub cover using 2012 National Agriculture Imagery Program imagery. We then modeled the relationship between gas field elements, pygmy rabbit presence, and two indices of pygmy rabbit abundance. Gas field infrastructure elements—specifically buried utility corridors and a complex of gas well pads, adjacent disturbed areas, and well pad access roads—were negatively correlated with pygmy rabbit presence and abundance indices, with sharp declines apparent after approximately 2% of the area consisted of gas field infrastructure. We conclude that pygmy rabbits in southwestern Wyoming may be sensitive to gas field development at levels similar to those observed for greater sage‐grouse, and may suffer local population declines at lower levels of development than are allowed in existing plans and policies designed to conserve greater sage‐grouse by limiting the surface footprint of energy development. Buried utilities, gas well pads, areas adjacent to well pads, and well pad access roads had the strongest negative correlation with pygmy rabbit presence and abundance. Minimizing the surface footprint of these elements may reduce negative impacts of gas energy development on pygmy rabbits.

The relative importance of local versus landscape variables on site occupancy in bats of the Brazilian Cerrado

Context Species site-occupancy patterns may be influenced by habitat variables at both local and landscape scales. Although local habitat variables influence whether the site is suitable for a given species, the broader landscape context can also influence site occupancy, particularly for species that are sensitive to land-use change.

Multidomain Human Peroxidasin 1 Is a Highly Glycosylated and Stable Homotrimeric High Spin Ferric Peroxidase

Human peroxidasin 1 (hsPxd01) is a multidomain heme peroxidase that uses bromide as a cofactor for the formation of sulfilimine cross-links. The latter confers critical structural reinforcement to collagen IV scaffolds. Here, hsPxd01 and various truncated variants lacking nonenzymatic domains were recombinantly expressed in HEK cell lines. The N-glycosylation site occupancy and disulfide pattern, the oligomeric structure, and unfolding pathway are reported. The homotrimeric iron protein contains a covalently bound ferric high spin heme per subunit with a standard reduction potential of the Fe(III)/Fe(II) couple of -233 ± 5 mV at pH 7.0. Despite sequence homology at the active site and biophysical properties similar to human peroxidases, the catalytic efficiency of bromide oxidation (kcat/KM(app)) of full-length hsPxd01 is rather low but increased upon truncation. This is discussed with respect to its structure and proposed biosynthetic function in collagen IV cross-linking.

Urban land use decouples plant-herbivore-parasitoid interactions at multiple spatial scales.

Intense urban and agricultural development alters habitats, increases fragmentation, and may decouple trophic interactions if plants or animals cannot disperse to needed resources. Specialist insects represent a substantial proportion of global biodiversity and their fidelity to discrete microhabitats provides a powerful framework for investigating organismal responses to human land use. We sampled site occupancy and densities for two plant-herbivore-parasitoid systems from 250 sites across a 360 km2 urban/agricultural landscape to ask whether and how human development decouples interactions between trophic levels. We compared patterns of site occupancy, host plant density, herbivory and parasitism rates of insects at two trophic levels with respect to landcover at multiple spatial scales. Geospatial analyses were used to identify landcover characters predictive of insect distributions. We found that herbivorous insect densities were decoupled from host tree densities in urban landcover types at several spatial scales. This effect was amplified for the third trophic level in one of the two insect systems: despite being abundant regionally, a parasitoid species was absent from all urban/suburban landcover even where its herbivore host was common. Our results indicate that human land use patterns limit distributions of specialist insects. Dispersal constraints associated with urban built development are specifically implicated as a limiting factor.

Spatial and Temporal Habitat Segregation of Mosquitoes in Urban Florida

Understanding mechanisms fostering coexistence between invasive and resident species is important in predicting ecological, economic, or health impacts of invasive species. The non-native mosquitoes Aedes aegypti and Culex quinquefasciatus have been resident in the southeastern United States for over a century. They coexist at some urban sites with the more recent invasive Aedes albopictus, which is usually superior in interspecific competition. We tested predictions of temporal and spatial habitat segregation that foster coexistence of these resident species with the superior invasive competitor. We measured spatial and temporal patterns of site occupancy and abundance for all three species among standard oviposition traps in metropolitan Tampa, Florida. Consistent with the condition-specific competition hypothesis, A. albopictus and A. aegypti abundances were greater and C. quinquefasciatus abundance was lower late (September) versus early (June) in the rainy season, and the proportional increase of A. albopictus abundance was greater than that of A. aegypti. These results are postulated to result from greater dry-season egg mortality and associated greater rainy-season competitive superiority of larvae of A. albopictus, followed by A. aegypti, and C. quinquefasciatus. Spatial partitioning among landscape variables was also evident among species, with A. albopictus more likely to oviposit across a range of open grass landscapes whereas A. aegypti were mostly restricted to cemeteries. Culex quinquefasciatus showed a shift in abundance from cemeteries early in the rainy season to developed areas characterized by built environments with large proportions of impervious surfaces late in the rainy season, where A. albopictus was not in its highest abundance. These results suggest that both temporal and spatial variation, and their interaction, may contribute to local coexistence between Aedes and Culex mosquito species in urban areas.

Habitat fragmentation reduces occupancy of nest boxes by an open-country raptor

SummaryDespite the recent rapid decline of many grassland bird species, the relative importance of habitat configuration to population persistence is unclear. We used Southeastern American KestrelsFalco sparverius paulusin north-central Florida as a model system to explore the relative influence of landscape structure components on site occupancy patterns at two spatial scales, and for two different time periods. We focused on the dynamic processes of site-level population expansion or contraction. We modelled the occupancy of 131 American Kestrel nest boxes with Bayesian state-space dynamic occupancy models that considered both the partially observed process of true occupancy and the probability of detection of occupancy. We used reversible jump Markov chain Monte Carlo (RJMCMC) algorithms to identify variables that described the continued occupancy of nest boxes, or ϕ, and the probability of colonisation of nest boxes between time periods, or γ3. Changes in open habitat patch isolation at a fine scale, as estimated by the variability of nearest neighbour distance, predicted site colonisation between decades, and patch shape variability was related to ϕ during the early time period (1992–93). We found no strong effects of landscape structure on ϕ during the later time period (2008–2010). We also found no evidence for effects of loss of open habitat on box occupancy or colonization. Our results indicate that continued habitat fragmentation would be deleterious for this threatened subspecies. Additionally, certain land cover management practices recommended for the Florida sandhills, such as frequent low-intensity controlled burns, will likely help conservation attempts.

Integrating aspects of ecology and predictive modelling: implications for the conservation of the leopard cat (Prionailurus bengalensis) in the Eastern Himalaya

An understanding of species ecology is vital for effective conservation, particularly if the species forms an important constituent of the lesser mammal guild and regulates small mammal and bird populations. As the ecological role of the leopard cat (Prionailurus bengalensis) in the intricate eastern Himalayan habitats is not known, we assessed the site occupancy, detection probability and activity pattern of leopard cats in Khangchendzonga Biosphere Reserve, India, based on sign surveys and camera trapping. The estimated site occupancy was 0.352 ± 0.061 and detection probability was 0.143 ± 0.0484. Occupancy modelling indicated low elevation, high rodent abundance and tree cover as best predictors for the occupancy of leopard cat. Diet based on analysed scats revealed murids as the most dominant prey (89.2 %). Information based on photographic captures indicated that the leopard cat exhibited a nocturnal activity pattern (peak activity between 0200–0300 hours), which coincided with its principal prey (revealed through diet analysis), but mainly contradicted with other sympatric competitors, hence indicating a temporal partitioning of resources among them. Ecological niche factor analysis indicated that the leopard cat exhibits high global marginality (1.32) and low global tolerance (0.275). The habitat suitability map for leopard cats showed majority of the habitat as unsuitable (1,959.44 km2) and predicted only 164.54 km2 areas of lower temperate forests as moderate to highly suitable. As highly suitable habitats of the leopard cat are in close proximity to villages, conflict issues are a major threat and therefore need to be addressed in conservation program for this felid.

Site Preference and Ordering Induced by Au Substitution in the γ-Brass Related Complex Au–Cr–Zn Phases

The crystal chemistry of the ternary Au-Cr-Zn alloy was studied by means of synthesis, single crystal X-ray diffraction, and electron structure calculations. While the compound CrZn(∼17) represents the binary end-point of the homogeneity range, the inclusion of Au proves to be very site specific, and at the limiting composition Au10Cr4Zn89 the structure is completely ordered. The crystallographic site occupancy pattern calculated by the Local Density Approximation (LDA)-Density Functional Theory (DFT) parametrized extended Hückel (eH) Mulliken charge populations in Au10Cr4Zn89 agrees very well with the experimentally found site occupancy pattern.

Can Camera Traps Monitor Komodo Dragons a Large Ectothermic Predator?

Camera trapping has greatly enhanced population monitoring of often cryptic and low abundance apex carnivores. Effectiveness of passive infrared camera trapping, and ultimately population monitoring, relies on temperature mediated differences between the animal and its ambient environment to ensure good camera detection. In ectothermic predators such as large varanid lizards, this criterion is presumed less certain. Here we evaluated the effectiveness of camera trapping to potentially monitor the population status of the Komodo dragon (Varanus komodoensis), an apex predator, using site occupancy approaches. We compared site-specific estimates of site occupancy and detection derived using camera traps and cage traps at 181 trapping locations established across six sites on four islands within Komodo National Park, Eastern Indonesia. Detection and site occupancy at each site were estimated using eight competing models that considered site-specific variation in occupancy (ψ)and varied detection probabilities (p) according to detection method, site and survey number using a single season site occupancy modelling approach. The most parsimonious model [ψ (site), p (site*survey); ω = 0.74] suggested that site occupancy estimates differed among sites. Detection probability varied as an interaction between site and survey number. Our results indicate that overall camera traps produced similar estimates of detection and site occupancy to cage traps, irrespective of being paired, or unpaired, with cage traps. Whilst one site showed some evidence detection was affected by trapping method detection was too low to produce an accurate occupancy estimate. Overall, as camera trapping is logistically more feasible it may provide, with further validation, an alternative method for evaluating long-term site occupancy patterns in Komodo dragons, and potentially other large reptiles, aiding conservation of this species.

Ecology of black cockatoos at a mine-site in the eastern jarrah-marri forest, western Australia.

Three threatened black cockatoos inhabit the Jarrah Eucalyptus marginata-Marri Corymbia calophylla forest of southwestern Australia: Baudin’s Cockatoo Calyptorhynchus baudinii, Carnaby’s Cockatoo C. latirostris, and Forest Redtailed Black Cockatoo C. banksii naso [FRTBC]. Their local ecology in relation to anthropogenic disturbance is poorly known, hampering effective conservation management. Therefore we studied their group size, site occupancy patterns, habitat use, and food plants at a mine-site and its surrounds in the eastern forest over three years. FRTBC showed similar group sizes and occupancy across seasons, suggesting year-round residency and no marked seasonality in movements and grouping patterns. In contrast, Carnaby’s Cockatoos were up to twice as abundant in spring and summer, indicating migrating or transient flocks and some year-round residents. Few Baudin’s Cockatoos were present in summer, but their abundance increased at other times. All three cockatoos were observed in modified or humanmade habitats such as mine-site rehabilitation, farm paddocks, and pine plantations. Carnaby’s Cockatoos used the broadest habitat range. We documented feeding on 16 plant species, with Carnaby’s Cockatoos eating at least 10. Examination of feeding residues as well as observations of behaviour were essential to obtain a complete picture of feeding. Current mine-site rehabilitation protocols provide food for all three black cockatoos within a decade and should continue to do so long-term if Marri is maintained in the seed mix. However, because climate change scenarios predict declining rainfall over much of southwestern Australia, the plant species used to revegetate mine-sites and other landscapes may need to be reconsidered. For areas that do not specify restoring a jarrah forest landscape, the selective use of exotic or non-endemic flora better adapted to lower rainfall conditions may be an option.

Validation of a citizen science-based model of coyote occupancy with camera traps in suburban and urban New York, USA

We evaluated the accuracy of a previously published model of coyote (Canis latrans) sightings in suburban Westchester County, New York. This model was originally developed using citizen reports of coyote sightings to predict the probability of a human-coyote interaction based on proximity to habitat features. Because the data were obtained from surveys, researchers could not separate patterns of site occupancy by coyotes from possible patterns of detection by respondents. Nevertheless, the model could be an indicator of site occupancy within the suburban matrix. We sought to evaluate the predictive power of the human-coyote interaction model with data gathered via a more rigorous method. To build a set of validation sites, we surveyed 11 parks in Westchester County and one park in Bronx County, NY with camera traps between April and October of 2010. The probability of photographing a coyote in a single trap-night was 0.06 ± 0.12 and all sites had >0.9 probability of detecting a coyote at least once given the total trap-nights at each site. During validation, we also added four additional sites that had been surveyed by other researchers with camera traps as additional “present” sites. Predictions of coyote presence or absence based on the human-coyote interaction model for these 16 validation sites were compared to the observed survey results. The model, which contained distances to forest, grassland, and pooled medium and high development performed well in predicting the observed data (kappa = 0.75 ± 0.17, Area-Under-Curve of Receiver-Operator-Characteristic plots = 0.90). The model appears to sufficiently predict coyote occupancy in a suburban-urban landscape and will form the basis of for development of a more comprehensive model of coyote distribution in the New York City metropolitan area. Furthermore, its accuracy illustrates how citizen science can provide reliable estimates of wildlife-habitat patterns in urban areas.

Response of leopards to re-introduced tigers in Sariska Tiger Reserve, Western India

Tigers got exterminated from Sariska Tiger Reserve before 2005. After that, five tigers were re-introduced to Sariska during 2008 to 2010. The present study compared the abundance, site occupancy and temporal activity pattern of leopard before and after tiger re-introduction. The population of leopard was estimated by mark-recapture technique using camera traps during 2008 to 2010 in an effective trapping area of 223.3 km2. Before tiger re-introduction (2008), the leopard density was estimated to be 7.6±0.6 (SE) /100 km2 and after tiger reintroduction it was 6.2±0.8 /100 km2(2009) and 3.1±0.4 /100 km2 (2010). It was observed that the density of leopard declined significantly (Two sample T-Test; P = 0.0002) from 2008 to 2010. Rate of site occupancy was calculated through site-wise capture history of leopard obtained from camera traps. Before tiger re-introduction the probability of site utilization of leopard was 0.75, while after tiger re-introduction probabilities of site utilization of leopard and tiger were estimated at 0.54 and 0.52 respectively and the co-occurrence of both the species was 0.51. Temporal activity patterns of tiger and leopard were investigated from photo captures. Prior to the release of tigers, mean activity time of leopard was 20: 57 h (95% CI 20: 19 to 22: 53) but shifted to 22: 35 h (21: 02 to 01: 25 h) after tiger release (Watson’s U2 test: p<0.005). The present study showed that there was a decline in the leopard population after tiger re-introduction and considerable segregation between the two carnivores along the spatial and temporal axes. Key words: Competition, density, leopard, population, reintroduction, spatial distribution, temporal activity, tiger.