scholarly journals Habitat Occupancy by Spruce Grouse (Canachites canadensis) in the south of its range, Québec, Canada

2021 ◽  
Author(s):  
Clara Casabona i Amat ◽  
Pierre Blanchette ◽  
André Desrochers
Keyword(s):  
Bird Species ◽  
Probability Of Detection ◽  
Coniferous Forests ◽  
Range Limit ◽  
Isolated Populations ◽  
Imperfect Detection ◽  
Occupancy Modelling ◽  
Habitat Occupancy ◽  
Management Measures ◽  
Temperate Deciduous Forests

Studying habitat occupancy at the margins of species’ distributions can be helpful in clarifying species’ requirements and planning management measures. Spruce grouse (Canachites canadensis Linnaeus, 1758), a bird species associated with northern short-needle coniferous forests in North America, has its southeastern range limit where coniferous forests are mixed with temperate deciduous forests and agricultural lands. Some isolated populations are found in these habitats. Using a single-season occupancy modelling approach, we investigated habitat use by spruce grouse, accounting for imperfect detection, in the lowlands of the St. Lawrence River in southern Québec, Canada. We conducted call-response spruce over three years at 279 sites (59 sites in 2007, 100 sites in 2008 and 120 sites in 2009). At the site level, the probability of occupancy was 21% (IC: 10.7% - 37.9%) and probability of detection was 54% (IC: 34.7% - 73.0%). Based on the covariates in the models, occurrence increased with higher cover of coniferous trees and low deciduous shrubs, and decreased with higher cover of deciduous trees. Finally, detection probability was highest at the beginning of the survey (50% in late April) and was influenced by year.

scholarly journals Dramatic decline of François' langur Trachypithecus francoisi in Guangxi Province, China

Oryx ◽  
2007 ◽  
Vol 41 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Youbang Li ◽  
Chengming Huang ◽  
Ping Ding ◽  
Zheng Tang ◽  
Chris Wood
Keyword(s):  
Population Size ◽  
Conservation Status ◽  
Guangxi Province ◽  
Isolated Populations ◽  
Term Survival ◽  
Management Planning ◽  
Management Measures ◽  
Species Survival ◽  
Dramatic Decline ◽  
Trachypithecus Francoisi

Interviews with local people and a survey were carried out in 23 counties of south-west Guangxi Province from April 2002 to June 2003 to evaluate the conservation status of François' langur Trachypithecus francoisi and assess the extent and nature of threats to the species' survival. François' langurs were found in only 10 counties compared with their presence in 23 counties before 1990. The total population size is estimated to be 307 individuals in 14 isolated populations. This represents a 90% decrease in population size since the early 1980s and an 85% decrease since the mid 1990s. The primary threat to the langur is hunting, mainly for traditional medicine. Our results suggest that conservation efforts for the species have been ineffectual during the last decade and, even within reserves, few direct management measures seem to have been taken to protect and conserve the langurs. Without the instigation of such measures it seems likely that François' langur will disappear both inside and outside reserves. To ensure the long-term survival of Francois' langur in Guangxi Province increased investment and improved management, planning, and training of reserve managers and staff is required, with a particular focus on the key remaining reserves and sites for the langur. Some of this work is now underway.

scholarly journals Conservation value of a native forest fragment in a region of extensive agriculture

2000 ◽  
Vol 60 (2) ◽  
pp. 237-247 ◽  
Author(s):  
A. G. CHIARELLO
Keyword(s):  
Deciduous Forest ◽  
Puma Concolor ◽  
Bird Species ◽  
Line Transect ◽  
Native Forest ◽  
Muscovy Duck ◽  
Forest Fragment ◽  
Isolated Populations ◽  
Mammal Species ◽  
Maned Wolf

A survey of mammals and birds was carried out in a semi-deciduous forest fragment of 150 ha located in a zone of intensive agriculture in Ribeirão Preto, State of São Paulo, south-eastern Brazil. Line transect sampling was used to census mammals and birds during six days, totalling 27.8 km of trails and 27.8 hours of observation. Twenty mammal species were confirmed in the area (except bats and small mammals), including rare or endangered species, such as the mountain lion (Puma concolor), the maned wolf (Chrysocyon brachyurus), and the ocelot (Leopardus pardalis). The brown capuchin monkey (Cebus apella) and the black-tufted-ear marmoset (Callithrix penicillata) were found frequently, suggesting high population density in the fragment. Regarding the avifauna, 49 bird species were recorded, most of them typical of open areas or forest edges. Some confirmed species, however, are becoming increasingly rare in the region, as for example the muscovy duck (Cairina moschata) and the toco toucan (Ramphastos toco). The results demonstrate that forest fragment of this size are refuges for native fauna in a region dominated almost exclusively by sugar-cane plantations. Besides faunal aspects, the conservation of these fragments is of great importance for the establishment of studies related to species preservation in the long term, including reintroduction and translocation projects, as well as studies related to genetic health of isolated populations.

Conventional distance sampling versus strip transects and abundance indices for estimating abundance of greater gliders (Petauroides volans) and eastern ringtail possums (Pseudocheirus peregrinus)

2019 ◽  
Vol 46 (6) ◽  
pp. 518
Author(s):  
Luke D. Emerson ◽  
Guy-Anthony Ballard ◽  
Karl Vernes
Keyword(s):  
Distance Sampling ◽  
Probability Of Detection ◽  
Density Estimate ◽  
Imperfect Detection ◽  
Density Estimates ◽  
Transect Line ◽  
Eucalypt Forest ◽  
Arboreal Marsupials ◽  
Abundance Indices ◽  
Strip Transect

Abstract ContextAccurate estimates of abundance are extremely useful for wildlife management and conservation. Estimates generated from distance sampling are typically considered superior to strip transects and abundance indices, as the latter do not account for probability of detection, thereby risking significant error. AimTo compare density estimates generated from conventional distance sampling (CDS) of arboreal marsupials with strip transect density estimates and abundance indices. MethodsOff-track CDS and strip transects were used to estimate densities of P. volans and P. peregrinus across ~2.6km2 of remnant eucalypt forest at Mt Duval in north-eastern New South Wales. Key resultsCDS density estimates for P. volans (1.36ha−1, 95% confidence interval (CI) of 1.07–1.72ha−1) and P. peregrinus (0.28ha−1, 95% CI 0.22–0.35ha−1) were consistent with densities reported in other studies conducted in open eucalypt forests. A strip transect width of 40m for P. volans resulted in a collective set of values for density (1.35ha−1), error (s.e.±0.14), precision (cv 0.10) and 95% CI (1.07–1.62ha−1) closest to those associated with the CDS-generated density estimate (1.36ha−1, s.e.±0.15, cv 0.10, 95% CI 1.07–1.72ha−1). Strip widths of 10 to 40m resulted in density estimates for P. peregrinus closest to those generated through CDS, but much less precise. ConclusionsAlthough a 40-m wide strip transect provided a robust density estimate for P. volans at Mt Duval, this is unlikely to be consistent across different study areas. Strip transects provided less precise density estimates, or underestimated P. peregrinus density at Mt Duval, when compared with CDS density estimates. CDS should be favoured over strip transects or abundance indices for estimating P. volans and P. peregrinus abundance, because it is capable of providing more meaningful and robust abundance estimates by accounting for the probability of detection from the transect line across different habitats. ImplicationsResearchers, conservation managers and decision makers should be aware that common methods for assessing arboreal marsupial abundance have serious potential weaknesses. Thus, it would be prudent to invest in studies that address imperfect detection to improve the quality of monitoring data.

Using multistate occupancy estimation to model habitat use in difficult-to-sample watersheds: bridle shiner in a low-gradient swampy stream

2013 ◽  
Vol 70 (10) ◽  
pp. 1429-1437 ◽  
Author(s):  
Timothy Jensen ◽  
Jason C. Vokoun
Keyword(s):  
Habitat Use ◽  
Aquatic Organisms ◽  
Probability Of Detection ◽  
High Abundance ◽  
Occupancy Models ◽  
Imperfect Detection ◽  
Patch Occupancy ◽  
Rare Minnow ◽  
Occupancy Estimation ◽  
Bridle Shiner

We used multiseason, multistate patch occupancy models to investigate habitat use of a regionally rare minnow (bridle shiner, Notropis bifrenatus) within a difficult-to-sample, swampy stream system by defining occupancy states as coarse abundance categories (i.e., none, some, many). Habitat patches were repeatedly subsampled during three sampling periods spanning June to August 2011 using a nonstandard purse-and-lift method with a seine net, as poorly defined shorelines, unconsolidated substrate, and emergent vegetation limited beaching and restricted possible sampling locations. Detection probabilities increased from June to August, likely due to increasing catch per effort as age 0 became vulnerable to the gear, supported by the probability of detection being greater when the species was at high abundance, given occupancy. The probability of a habitat patch being occupied increased with the percent of macrophyte cover and decreased with increasing distance from another occupied patch. Decreasing mean depth showed a weak relationship to high abundance, given a patch was occupied. In summary, the multistate occupancy analytical approach was highly informative for developing quantitative habitat relationships and was seen as an effective framework for evaluating habitat use of aquatic organisms that inhabit environments inherently difficult to sample for which imperfect detection and sampling efficiency are of concern.

Comparative aspects of blood coagulation measurements in various wild and captive bird species

2017 ◽  
Vol 45 (04) ◽  
pp. 246-252
Author(s):  
Karl Rohn ◽  
Norbert Kummerfeld ◽  
Reinhard Mischke ◽  
Vanessa Guddorf
Keyword(s):  
Bird Species ◽  
Measurement Range ◽  
Avian Species ◽  
Thrombin Time ◽  
Plasma Samples ◽  
Range Limit ◽  
Healthy Individuals ◽  
Coagulation Activation ◽  
Captive Bird ◽  
Avian Blood

SummaryObjective: Information about the influence of species variety or diseases on coagulation values in avian blood is rare. The aim of this study was to assess the influence of species on measurements of coagulation parameters in avian plasma samples using commercially available reagents and to investigate potential influences of selected diseases on clotting times. Material and methods: Prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) were measured in citrated plasma of healthy individuals collected from eight different wild and captive avian species applying currently commercially available reagents prepared for use in humans, which were preselected in preliminary studies. The same parameters were tested in plasma samples from birds affected by aspergillosis, atherosclerosis, neoplasia and traumata. Results: PT and aPTT showed a high interspecies variety. Irrespective of species, aPTTs were extremely long and partially exceeded the measurement range limit. Minor variations between species were seen in TT measurements. Clotting times obtained from birds affected by aspergillosis, atherosclerosis and neoplasia were not significantly different when compared to healthy birds. Plasma obtained from traumatised individuals showed significantly shorter PT and aPTT than that in healthy birds. Conclusion and clinical relevance: Differences between species must be considered in diagnostic coagulation measurements in avian blood. Regardless of the avian species, aPTT measurements on avian samples appear to be of limited value. Lower PT and aPTT values reflect coagulation activation in traumatised birds.

scholarly journals Multiscale effects of wetland availability and matrix composition on wetland breeding birds in Minnesota, USA

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Sarah P Saunders ◽  
Kristin A L Hall ◽  
Nina Hill ◽  
Nicole L Michel
Keyword(s):  
Spatial Scale ◽  
Habitat Management ◽  
Spatial Scales ◽  
Bird Species ◽  
Matrix Composition ◽  
Bird Diversity ◽  
Bird Conservation ◽  
Prairie Pothole ◽  
Imperfect Detection ◽  
Matrix Habitat

Abstract The increasing intensity of wetland stressors in the Upper Midwestern United States hastens the need to understand how matrix composition influences wetland bird occurrence and abundance. The optimal spatial scale for assessing species–habitat relationships is not always apparent, but may affect inference about wetland use and suitability. We developed occupancy and abundance models, accounting for imperfect detection, for 9 wetland bird species breeding in Minnesota. We evaluated land cover associations at 3 spatial scales (12.6 ha, 50.3 ha, and 4,000 ha), quantified species-specific sensitivity to wetland availability and matrix habitat composition (agricultural and developed land covers), and assessed ecoregional variation in occupancy and abundance. Amount of wetland cover was positively associated with occupancy of 89% of species and with abundance of 67% of species, but the spatial scale of support differed among species. American Bittern (Botaurus lentiginosus), Pied-billed Grebe (Podilymbus podiceps), and Wilson’s Snipe (Gallinago delicata) in particular were negatively impacted by anthropogenic land uses within the surrounding matrix, indicating a need to shift wetland conservation planning from the site scale to the landscape scale to capture pertinent drivers of wetland bird habitat use. Mean expected occupancy across all species was greatest in the Prairie Pothole Region (PPR), suggesting that restoration efforts within this ecoregion are likely to maintain wetland bird diversity. However, given the minimal total wetland availability and predominantly agricultural matrix in the PPR, protecting wetlands and upland buffers in the Aspen Parklands or Boreal ecoregions may represent a better investment for agricultural-sensitive species such as American Bittern, Sandhill Crane (Antigone canadensis), and Wilson’s Snipe. Our modeling approach provides a multi-species framework for identifying habitat management priorities; future applications at broader spatial extents can continue to improve wetland bird conservation in a region with high rates of wetland loss and degradation.

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

2014 ◽  
Vol 24 (3) ◽  
pp. 364-378 ◽  
Author(s):  
JESSI L. BROWN ◽  
MICHAEL W. COLLOPY ◽  
JOHN A. SMALLWOOD
Keyword(s):  
Habitat Fragmentation ◽  
Landscape Structure ◽  
Spatial Scales ◽  
Bird Species ◽  
Probability Of Detection ◽  
American Kestrel ◽  
Open Habitat ◽  
Nest Boxes ◽  
Time Period ◽  
Time Periods

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.

scholarly journals Evaluation of the analysis of distance sampling data: a simulation study

Ornis Svecica ◽  
2010 ◽  
Vol 20 (1) ◽  
Author(s):  
Robert Ekblom
Keyword(s):  
Distance Sampling ◽  
Bird Species ◽  
Simulated Data ◽  
Probability Of Detection ◽  
Parameter Estimates ◽  
Area Of Interest ◽  
Field Situation ◽  
Wide Range ◽  
Density Values ◽  
Distance Data

Distance sampling is used to estimate number of individuals in an area of interest. The idea is that with known distances to the observed individuals, one can model the probability of detection in relation to distance and thereby account for individuals that were not detected. Distances can be recorded either exactly or in discrete categories. In this study I validated the method using simulated distance sampling data for two hypothetical bird species and compared the estimated density values to the known true densities. Generally the true densities and numbers of individuals were very similar to (and always within the 95% confidence interval of) the parameter estimates from the analysis of the simulated data. The analyses were also robust to modifications of the data such as truncation and grouping of the distances into discrete categories. The confidence intervals increased, however, when using only two distance groups. Given that critical assumptions of the model can be met in the field situation, distance data can thus be used in a wide range of bird studies to calculate reliable density estimates.

Changing Habitat Use by Birds after the Exxon Valdez Oil Spill

2003 ◽  
Vol 2003 (1) ◽  
pp. 531-537
Author(s):  
Robert H. Day ◽  
Stephen M. Murphy ◽  
John A. Wiens ◽  
Keith R. Parker
Keyword(s):  
Habitat Use ◽  
Oil Spill ◽  
Bird Species ◽  
Exxon Valdez ◽  
Data Set ◽  
Exxon Valdez Oil Spill ◽  
Habitat Occupancy ◽  
Time Period ◽  
Negative Impacts ◽  
Intertidal Habitats

ABSTRACT We examined the effects of the Exxon Valdez oil spill on mid-summer habitat occupancy by marine-oriented birds during 1989–2001 in Prince William Sound, Alaska, by extending our earlier 1989–1991 data set and analyzing the entire data set as a time-series. Intertidal habitats in the spill-affected area have been recovering, as indicated by significant temporal increases in the proportional coverage of rockweed (Fucus) and mussels (Mytilus) in oiled bays. Of the 25 bird species we examined, 12 (48%) exhibited no evidence of impacts, 10 (40%) exhibited negative impacts that subsequently disappeared, and 3 (12%) exhibited positive relationships with oiling that subsequently disappeared. No species provided clear evidence of delayed impacts, and all of the impacted species exhibited recovery by 2001. In comparison with our 1989–1991 study, we detected a slightly greater proportion of initial spill impacts in this study and were able to document recovery in habitat occupancy of several species that had not recovered by 1991. The present study, however, incorporates 1984 baseline data and a longer time-period for examination of impacts and recovery. Differences between our conclusions and those of other researchers on the effects of the Exxon Valdez oil spill on habitat use by birds may reflect differences in study design, criteria used to assess impacts and recovery, and definitions of “recovery.” These differences illustrate the difficulties of evaluating the consequences of environmental accidents, even large ones.

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