Robert S. Rempel

PERFORMANCE OF A GPS ANIMAL LOCATION SYSTEM UNDER BOREAL FOREST CANOPY

An automated animal location system, based on Global Positioning System (GPS) technology, is being used for wildlife research. The GPS is a divergent technology, and positional accuracies vary between millimeters and tens of meters, depending on the system used and operating conditions. Before GPS-based tracking data can be used for habitat analyses, the influence of habitat on GPS-collar performance must be evaluated under various canopy conditions, including the optimal condition of no canopy. We evaluated performance of nondifferentially corrected GPS collars in an experimental forest with mature, evenly spaced trees and on wild free-ranging moose (Alces alces) to determine the influence of canopy on positional accuracy and observation rate. In an experimental forest with mature, evenly spaced trees (henceforth called spacing trial), canopy characteristics of tree species, spacing, height, basal diameter, and canopy closure had no influence on positional accuracy (P > 0.05), but had an influence on GPS observation rate (P < 0.001). Location error was greater if positions were based on 2-dimensional rather than 3-dimensional mode of operation (P < 0.001), with location errors of 65.5 and 45.5 m, respectively. Location error in 3-dimensional mode did not differ from the expected error of 40 m (P = 0.43). As tree density increased, observation rate decreased and the probability of the GPS receiver operating in 2-dimensional mode increased (P < 0.001), resulting in increased location error. With future development of differentially corrected GPS collars, location errors of <10 m are expected. J. WILDL. MANAGE. 59(3):543-551

Effects of differential correction on accuracy of a GPS animal location system

The location error of uncorrected data from Global Positioning System (GPS) collars range from ca. 45.5 to 65.5 m (Rempel et al. 1995). Improvements that potentially could reduce locational error to <10 m include correcting systematic bias by reference to GPS data collected at a known position (differential correction), increase in the proportion of positions based on ranging 4 rather than 3 satellites (3-dimensional node), and increase in the proportion of positions based on a well-spaced satellite configuration (low dilution of precision). Design changes meant to achieve these results were implemented in the second generation GPS collars we evaluated (Lotek Eng. Inc. 1996). We tested the performance of these collars under the controlled canopy conditions of the Thunder Bay experimental forest. Differential correction caused location error to decrease from 80 to 4 m (P < 0.0001), and the range of 25-75th percentile location error to decrease from 74.3 to 5.0 m. Location error among sample sites was greatest under tall red pines (Pinus resinosa; 15.7 m), possibly because the tall trunks interfered with signal reception, resulting in the acceptance of either 2-dimensional mode positions or positions based on poor satellite configuration (high dilution of precision), or because of multipathing effects caused by signal bounce off the tree trunks. Implementation of differential correction may involve substantial costs to maintain a GPS basestation and data handling, so effectiveness of this enhanced technology must be judged against study objectives and data requirements of the hypotheses being tested.

Timber-management and natural-disturbance effects on moose habitat:landscape evaluation.

We used 16 years of survey data for a moose population, and 3 Landsat satellite scenes, spanning 19 years, to evaluate the hypotheses that Ontarios Moose Habitat Guidelines for timber harvest: (1) mitigate the effects of unmodified clearcuts on moose populations, and (2) create enhanced habitat with greater interspersion of forage with cover and higher habitat suitability indices than areas dominated by unmodified clearcuts. The 5 study landscapes compared were 16,000-91,000 ha, and included landscape disturbance from timber-management and wildfire-burn, and landscapes with and without hunter access. Moose density differed among landscapes, but while neither main effects of hunter access (P = 0.083), nor landscape disturbance (P = 0.31) were significant, their interactions were (P = 0.003), with density increasing if disturbance occurs without hunter access. The habitat suitability index in the wildfire burn was similar (0.80) to both the modified and unmodified clearcut (0.85 and 0.83), and population rate of increase was positive in both the burn (B = 0.153, P < 0.0001) and the unmodified clearcut (B = 0.127, P < 0.0001). The population did not increase in the modified clearcut (B = -0.016, P = 0.9907) because hunter access increased as a consequence of high road density.

Bioacoustic monitoring of forest songbirds: interpreter variability and effects of configuration and digital processing methods in the laboratory

Abstract Omnidirectional bioacoustic recording systems offer the ability to record forest songbirds in the field by technical staff, and then interpret the recordings later in the laboratory by skilled interpreters. Among several advantages to this approach are the ability to estimate variance among interpreters, obtain a permanent archival record of the point count, reduce costs by using regular field crews to collect data vs. those skilled in bird identification, and remove impediments to breeding bird surveys due to lack of available skilled birders. In this study we first evaluated the effects of microphone configuration and digital processing methods on the quality and effectiveness of the recordings, and then evaluated how consistently skilled birders interpreted the same songbird recordings collected under a mix of environmental conditions, and related this to the commonness of the species. At the time of this evaluation, the most cost-effective configuration of the bioacoustic monitoring system included use of a 180°/180° microphone combination, a minidisc digital recording system, analog transfer of the sound data via a digital soundcard, post-processing amplification of the signal, and data storage in an .MP3 format. This combination maintains high sound fidelity while minimizing both expense and data storage requirements. As recording device technology improves, the direct storage and digital transfer of .WAV format files will be the preferred and most effective recording option. Despite noisy conditions due to wind and other ambient sounds for many of the recordings, interpreters showed a high level of similarity in species identification and enumeration for the 34 most abundant species. Standardized coefficient of variance increased sharply when species had fewer than 10 occurrences, suggesting that birders are more variable in their identification of rare or uncommon species. Desktop identification systems that include type specimens of spectrographic signature and sound clips to aid interpreters could improve identification accuracy of rarer species.

Detecting scales of pattern in boreal forest landscapes

Abstract A hierarchy of processes operating at different spatial and temporal scales form landscape pattern, and changes to the patterns can have impacts on habitats and forest dwelling species. Managing landscapes under the auspices of sustainable forest ecosystems and emulation of natural disturbance requires knowledge of the scale at which landscapes are patterned. To better understand the role of natural disturbance in two distinct ecoregions of the Ontario boreal forest, we used thematic landcover maps derived from satellite imagery to evaluate differences in the relevant scales and nested hierarchies of forest pattern between two regions: northwest Ontario (relatively undisturbed forest and little fire suppression) and northeast Ontario (long history of forest harvest and fire suppression). We define a relevant scale as the spatial level where non-random patterning of landscape structure occurs. Similar nested hierarchies occurred in forest and wildfire disturbance classes in northwest Ontario. In contrast, the relevant scales detected in the northeast occurred at fewer levels and in the disturbance class, which was the result of forest harvest, at only one level. The differences detected between the two regions indicate that current forest harvest practices that focus on landscape alteration at a single scale are creating new landscapes that are different from the natural landscape.

Structural Characteristics of Post-Wildfire and Clearcut Landscapes

A continuing discussion in the field of ecology and forest management concerns the implications of clearcutting as a functional replacement for wildfire in disturbance-driven ecosystems. At the landscape level, spatial pattern has been shown to influence many ecologically important processes. Satellite imagery allows the evaluation of structural patterns created by alternative forest management activities at broad scales. In Northwestern Ontario, both clearcutting and wildfire have occurred over large contiguous areas. Spatial characteristics including composition, patch size, patch shape, and interspersion were calculated from classified Landsat Thematic Mapper (TM) data at two thematic scales and used to compare post-wildfire and clearcut landscapes. Patches in the clearcut landscape were found to be larger in size, and had a more irregular shape than those in the wildfire landscape. Differences in landscape structure were much more pronounced at broad scales than at fine thematic scales.

The influence of sampling scheme and interpolation method on the power to detect spatial effects of forest birds in Ontario (Canada)

Spatial ecology is becoming an increasingly important component of resource management, and the general monitoring of how human activities affect the distribution and abundance of wildlife. Yet most work on the reliability of sampling strategies is based on a non-spatial analysis of variance paradigm, and little work has been done assessing the power of alternative spatial methods for creating reliable maps of animal abundance. Such a map forms a critical response variable for multiple scale studies relating landscape structure to biotic function. The power to reconstruct patterns of distribution and abundance is influenced by sample placement strategy and density, the nature of spatial auto-correlation among points, and by the technique used to extrapolate points into an animal abundance map. Faced with uncertainty concerning the influence of these factors, we chose to first synthesize a model reference system of known properties and then evaluate the relative performance of alternative sampling and mapping procedures using it. We used published habitat associations of tree nesting boreal neo-tropical birds, a classified habitat map from the Manitou Lakes area of northwestern Ontario, and point count means and variances determined from field studies in boreal Canada to create 4 simulated models of avian abundance to function as reference maps. Four point sampling strategies were evaluated by 4 spatial mapping methods. We found mixed-cluster sampling to be an effective point sampling strategy, particularly when high habitat fragmentation was avoided by restricting samples to habitat patches >10 ha in size. We also found that of the 4 mapping methods, only stratified ordinary point kriging (OPK) was able to generate maps that reproduced an embedded landscape-scale spatial effect that reduced nesting bird abundance in areas of higher forest age-class fragmentation. Global OPK was effective only for detecting broader, regional-scale differences.

A SIMPLE WETLAND HABITAT CLASSIFICATION FOR BOREAL FOREST WATERFOWL

We propose a wetland habitat classification for boreal forest waterfowl that builds on existing clas- sification systems, and apply the habitat classification to wetlands surveyed for 14 species of waterfowl breeding pairs and broods in the boreal Claybelt of Ontario. The habitat classification is based on simple and easily observable structural characteristics measured from black-and-white aerial photography collected for forest resource inventories. Habitat associations were examined using x2 analysis for individual waterfowl species, and canonical correspondence analysis for overall community structure. Habitat use deviated significantly from that expected by random association for both pairs and broods, and canonical ordination of habitat/community structure was significant for both breeding pairs and broods. Beaver-pond marshes, lacustrine marshes located at river mouths, and open-water fens with <25% vegetative cover were used at rates much higher than ex- pected, and deserve attention for conservation in the boreal forest. Based on expected distribution of wetland habitat types, we estimate 96.9 pairs x 100 km-2 and 96.1 broods x 100 km-2 to occur on average throughout the Claybelt. J. WILDL. MANAGE. 61(3):746-757

Selecting Focal Songbird Species for Biodiversity Conservation Assessment: Response to Forest Cover Amount and Configuration

Conservation of biodiversity is now a firmly entrenched objective of sustainable forest management, and emulating natural disturbance has been widely adopted as a conservation strategy. Yet the foundation for this approach is still very much a hypothesis based on first principles, and there has been little rigorous testing of the approach. In addition, practical constraints mean that the full range and character of natural patterns can never be implemented, so decisions must still be made in setting forest management targets and levels. An alternative, but complementary approach is to select a focal group of species and use their habitat requirements to define the range of conditions that should be maintained on the landscape. In this study, I used a balanced factorial sample design to test the effect of landscape vs. local scale factors for explaining relative abundance of 30 forest songbird species in boreal Ontario, and then examined components of variance, and used multivariate analysis and logistic regression to describe these relationships in more detail. Based on statistically defendable inferences and habitat model coefficients, 13 species were selected, with habitat associations ranging from high to low edge density, homogeneous to heterogeneous forest matrix, hardwood to softwood dominated overstory, young to old stands, and open to closed canopy. I found that variations in amount and configuration of mature forest cover had relatively little influence on the overall boreal forest songbird community, but that individual species differ in their response to these variables. To be successful, biodiversity conservation strategies must emulate the patterns created through natural disturbance by maintaining the full range of forest cover homogeneity and heterogeneity on the landscape. The habitat requirements for Alder Flycatcher, Black-and-white Warbler, Bay-breasted Warbler, Blackburnian Warbler, Brown Creeper, Common Yellowthroat, Chestnut-sided Warbler, Least Flycatcher, Ovenbird, Red-breasted Nuthatch, Red-eyed Vireo, Winter Wren, and Whitethroated Sparrow describe a broad range of habitat conditions that, at a minimum, describe necessary coarse-filter conditions to sustain the boreal songbird community in Ontario. This suite of species can also serve in developing a “bioassay” to evaluate the effectiveness of forest policy to conserve biodiversity through emulation of natural disturbance. RESUME. La conservation de la biodiversite est maintenant un objectif solidement etabli de l’amenagement durable des forets et l’imitation des perturbations naturelles a largement ete adoptee en tant que strategie de conservation. Toutefois, cette approche, qui se fonde sur une hypothese etablie sur des principes de base, a rarement fait l’objet de tests rigoureux. De plus, des contraintes pratiques font que l’eventail complet et le caractere meme des patrons naturels ne peuvent jamais etre reproduits, si bien que les decisions doivent encore etre prises en fonction d’objectifs et de niveaux d’amenagement forestier. Une approche alternative, mais complementaire, consiste a selectionner un groupe d’especes specialistes et a utiliser leurs exigences Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Faculty of Forestry and Forest Environment, Lakehead University Avian Conservation and Ecology Ecologie et conservation des oiseaux 2(1): 6 http://www.ace-eco.org/vol2/iss1/art6/ en termes d’habitat afin de definir la gamme des conditions qui devraient etre maintenues dans le paysage. Dans cette etude, j’ai utilise un plan d’echantillonnage factoriel equilibre pour tester quels sont les facteurs, a l’echelle du paysage et a l’echelle locale, qui pourraient expliquer l’abondance relative de 30 especes de passereaux forestiers dans le nord de l’Ontario. J’ai ensuite examine les composantes de la variance, puis utilise l’analyse multivariable et la regression logistique afin de decrire ces relations de facon plus detaillee. Treize especes ont ete selectionnees sur la base d’inferences statistiquement valables et de coefficients de modeles d’utilisation de l’habitat. Les variables de l’habitat et leurs caracteristiques etaient les suivantes : la densite de la bordure (d’elevee a faible), la matrice forestiere (d’homogene a heterogene), la composition de la strate arborescente (de feuillue a resineuse), l’âge du peuplement (de vieux a jeune) et la densite de la voute (d’ouverte a fermee). J’ai constate que les variations dans l’etendue et la configuration du couvert forestier des forets matures avaient relativement peu d’influence sur l’ensemble de la communaute de passereaux, mais que l’effet de ces variables fluctuait selon les especes. Pour etre efficaces, les strategies de conservation de la biodiversite doivent imiter les patrons crees par les perturbations naturelles, en maintenant l’eventail complet de l’homogeneite et de l’heterogeneite du couvert forestier du paysage. Les exigences en termes d’habitat requises par le Moucherolle des aulnes, la Paruline noir et blanc, la Paruline a poitrine baie, la Paruline a gorge orangee, le Grimpereau brun, la Paruline masquee, la Paruline a flancs marron, le Moucherolle tchebec, la Paruline couronnee, la Sittelle a poitrine rousse, le Vireo aux yeux rouges, le Troglodyte mignon et le Bruant a gorge blanche correspondent a un vaste eventail de conditions qui, a un seuil minimum, definissent les conditions necessaires du filtre brut pour soutenir la communaute boreale de passereaux en Ontario. Ce groupe d’especes peut aussi servir a developper un « test biologique » afin d’evaluer l’efficacite des politiques forestieres dans la conservation de la biodiversite au moyen de l’imitation des perturbations naturelles.

Binational climate change vulnerability assessment of migratory birds in the Great Lakes Basins: Tools and impediments

Climate change is a global concern, requiring international strategies to reduce emissions, however, climate change vulnerability assessments are often local in scope with assessment areas restricted to jurisdictional boundaries. In our study we explored tools and impediments to understanding and responding to the effects of climate change on vulnerability of migratory birds from a binational perspective. We apply and assess the utility of a Climate Change Vulnerability Index on 3 focal species using distribution or niche modeling frameworks. We use the distributional forecasts to explore possible changes to jurisdictional conservation responsibilities resulting from shifting distributions for: eastern meadowlark (Sturnella magna), wood thrush (Hylocichla mustelina), and hooded warbler (Setophaga citrina). We found the Climate Change Vulnerability Index to be a well-organized approach to integrating numerous lines of evidence concerning effects of climate change, and provided transparency to the final assessment of vulnerability. Under this framework, we identified that eastern meadowlark and wood thrush are highly vulnerable to climate change, but hooded warbler is less vulnerable. Our study revealed impediments to assessing and modeling vulnerability to climate change from a binational perspective, including gaps in data or modeling for climate exposure parameters. We recommend increased cross-border collaboration to enhance the availability and resources needed to improve vulnerability assessments and development of conservation strategies. We did not find evidence to suggest major shifts in jurisdictional responsibility for the 3 focal species, but results do indicate increasing responsibility for these birds in the Canadian Provinces. These Provinces should consider conservation planning to help ensure a future supply of necessary habitat for these species.