Counting Bears, P’s And Q’s: An Efficient Sample Design for a Spatial Capture Recapture Hair Snag Study of Grizzly Bears

Accurate assessment of abundance can be expensive and managers often seek to minimize costs. Because spatial capture recapture (SCR) methods explicitly account for variation in trap effort in space and time and permit the use of covariates to explain abundance, substantial flexibility in design and thus reduction in costs may be possible. Estimates of grizzly bear (Usus arctos) densities and abundances in 4 management units in Alberta were very low  (superpopulation n =  47-133) in the latest studies occurring from 2004-2008. Since these first provincial population estimates were obtained, management, landscape, and habitat conditions have changed. Managers would like updated abundance information but also seek to reduce the costs of acquiring these data. We assessed 1) the behavior of SCR models across several general sample designs and 2) whether we could eliminate sampling in helicopter-access-only areas in the Yellowhead management unit while maintaining accurate estimates. We used a combination of retrospective subsampling of existing data from a 2004 sampling effort and simulations to evaluate several designs. Placing sampling arrays in areas with high densities of bears decreased variance, while the fine-scale configuration of traps did not greatly influence estimates. Simulations of designs for Alberta with more intensive sampling of only the areas accessible by road and no sampling of more expensive helicopter-access-only areas provided robust estimates with little loss in precision. We will describe the framework and assumptions of SCR models with covariates for abundance in comparison with traditional capture recapture models

Interchangeable punishments during aversive conditioning in Drosophila

Using Drosophila melanogaster larvae we asked whether distinct aversive stimuli have a common neuralrepresentation during associative learning. We tested the interchangeability of heat shock and electroshock punishments when used within a single olfactory associative conditioning experiment. We find that compared to animals trained with the repetitive use of a single punishment, the use of two alternating punishments results in similar associative learning. Additionally, the two punishments are shown to have different sensory origins. Therefore, while punishments are processed differently by the larvae of Drosophila melanogaster, the value of the stimulus is preserved

Inferring invasive species abundance using removal data from management actions

Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480–19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small

Accounting for Location Uncertainty in Azimuthal Telemetry Data Improves Ecological Inference

Background: Characterizing animal space use is critical for understanding ecological relationships. Animal telemetry technology has revolutionized the fields of ecology and conservation biology by providing high quality spatial data on animal movement. Radio-telemetry with very high frequency (VHF) radio signals continues to be a useful technology because of its low cost, miniaturization, and low battery requirements. Despite a number of statistical developments synthetically integrating animal location estimation and uncertainty with spatial process models using satellite telemetry data, we are unaware of similar developments for azimuthal telemetry data. As such, there are few statistical options to handle these unique data and no synthetic framework for modeling animal location uncertainty and accounting for it in ecological models. We developed a hierarchical modeling framework to provide robust animal location estimates from one or more intersecting or non-intersecting azimuths. We used our azimuthal telemetry model (ATM) to account for azimuthal uncertainty with covariates and propagate location uncertainty into spatial ecological models. We evaluate the ATM with commonly used estimators (Lenth (1981) maximum likelihood and M-Estimators) using simulation. We also provide illustrative empirical examples, demonstrating the impact of ignoring location uncertainty within home range and resource selection analyses. We further use simulation to better understand the relationship among location uncertainty, spatial covariate autocorrelation, and resource selection inference. Results: We found the ATM to have good performance in estimating locations and the only model that has appropriate measures of coverage. Ignoring animal location uncertainty when estimating resource selection or home ranges can have pernicious effects on ecological inference. Home range estimates can be overly confident and conservative when ignoring location uncertainty and resource selection coefficients can lead to incorrect inference and over confidence in the magnitude of selection. Furthermore, our simulation study clarified that incorporating location uncertainty helps reduce bias in resource selection coefficients across all levels of covariate spatial autocorrelation. Conclusion: The ATM can accommodate one or more azimuths when estimating animal locations, regardless of how they intersect; this ensures that all data collected are used for ecological inference. Our findings and model development have important implications for interpreting historical analyses using this type of data and the future design of radio-telemetry studies

Fluxes in H\alpha and Ca II H and K for a sample of Southern stars

The main chromospheric activity indicator is the S index, which is esentially the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied basically for stars from F to K. Another usual chromospheric proxy is the H\alpha line, which is beleived to be tightly correlated with the Ca II index. In this work we characterize both chromospheric activity indicators, one associated with the H and K Ca II lines and the other with H\alpha, for the whole range of late type stars, from F to M. We present periodical medium-resolution echelle observations covering the complete visual range, which were taken at the CASLEO Argentinean Observatory. These observations are distributed along 7 years. We use a total of 917 flux-calibrated spectra for 109 stars which range from F6 to M5. We statistically study these two indicators for stars of different activity levels and spectral types. We directly derive the conversion factor which translate the known S index to flux in the Ca II cores, and extend its calibration to a wider spectral range. We investigate the relation between the activity measurements in the calcium and hydrogen lines, and found that the usual correlation observed is basically the product of the dependence of each flux with stellar colour, and not the product of similar activity phenomena.Comment: 12 pages, including 11 figures and 2 tables. Accepted for publication in Astronomy and Astrophysic

Rotational modulation of the photospheric and chromospheric activity in the young, single K2-dwarf PW And

High resolution echelle spectra of PW And (HD~1405) have been taken during eight observing runs from 1999 to 2002. The detailed analysis of the spectra allow us to determine its spectral type (K2V), mean heliocentric radial velocity (V_hel = -11.15 km/s) rotational velocity (vsin{i} = 22.6 km/s), and equivalent width of the lithium line 6707.8 AA (EW(LiI) = 273 mAA). The kinematic (Galactic Velocity (U, V, W)) confirms its membership of the Local Association moving group, in agreement with the age (30 to 80 Myrs) inferred from the color magnitude diagram and the lithium equivalent width. Photospheric activity (presence of cool spots that disturb the profiles of the photospheric lines) has been detected as changes in the the bisectors of the cross correlation function (CCF) resulting of cross-correlate the spectra of PW And with the spectrum of a non active star of similar spectral type. These variations of the CCF bisectors are related to the variations in the measured radial velocities and are modulated with a period similar to the photometric period of the star. At the same time, chromospheric activity has been analyzed, using the spectral subtraction technique and simultaneous spectroscopic observations of the H_alpha, H_beta, NaI D_1 and D_2$, HeI D_3, MgI b triplet, CaII H&K, and CaII infrared triplet lines. A flare was observed during the last observing run of 2001, showing an enhancement in the observed chromospheric lines. A less powerful flare was observed on 2002 August 23. The variations of the chromospheric activity indicators seem to be related to the photospheric activity. A correlation between radial velocity, changes in the CCF bisectors and equivalent width of different chromospheric lines is observed with a different behaviour between epochs 1999, 2001 and 2002.Comment: Latex file with 20 pages, 21 figures tar'ed gzip'ed. Full postscript (text, figures and tables) available at http://www.ucm.es/info/Astrof/users/dmg/pub_dmg.html Accepted for publication in: Astronomy & Astrophysics (A&A