scholarly journals Fine-scale plasticity in nest placement can compensate for poor quality junipers as nesting trees for gray vireos

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12477
Author(s):  
Jonathan Harris ◽  
Loren Smith ◽  
Scott McMurry
Keyword(s):  
Nest Survival ◽  
Tree Height ◽  
Information Criteria ◽  
Habitat Characteristics ◽  
Survival Probabilities ◽  
Species Of Conservation Concern ◽  
Nest Placement ◽  
Daily Nest Survival ◽  
Foliage Density ◽  
Conservation Concern

Understanding the interactions between behavior and habitat characteristics can have important implications for species of conservation concern. Gray vireos (Vireo vicinior) are one example of a species of conservation concern that is understudied in terms of nest survival probabilities and the habitat characteristics that influence them. Our objective was to determine if habitat features such as juniper density, juniper foliage density, or tree height influence nest survival probabilities, and if gray vireo nest placement can mitigate habitat risks. Based on previous work, we expected daily nest survival probabilities to be associated with nest height and surrounding vegetation. We monitored 89 nests in central New Mexico from 2016–2018 to estimate daily nest survival probabilities. We compared variation in nest placement, nest tree characteristics, and surrounding vegetation between failed and successful nests using logistic exposure models and Akaike Information Criteria. Daily and cumulative nest survival probability were 0.983 (95% CI [0.973–0.989]) and 0.575 (95% CI [0.444–0.702]), respectively. Top models predicting nest survival included a negative interaction between nest-tree foliage density and the distance of the nest from the edge of the nesting tree. This suggests that gray vireos can mitigate risks associated with low nest concealment by nesting closer to the interior of the nesting tree.

scholarly journals Avian Nesting Success in Forested Landscapes: Influence of Landscape Composition, Stand and Nest-Patch Microhabitat, and Biotic Interactions

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 1018-1028 ◽  
Author(s):  
Amanda D. Rodewald ◽  
Richard H. Yahner ◽  
J. Brawn
Keyword(s):  
Brood Parasitism ◽  
Nest Survival ◽  
Landscape Composition ◽  
Nesting Success ◽  
Habitat Characteristics ◽  
Parasitism Rates ◽  
Forested Landscapes ◽  
Daily Nest Survival ◽  
Landscape Types ◽  
Nest Predators

AbstractAlthough area and isolation effects on avian communities in highly fragmented landscapes are well known, importance of landscape composition in more forested landscapes remains poorly understood. We determined if the type (agriculture and silviculture) and extent (percentage within 1 km radius) of disturbance within forested landscapes influenced avian nesting success, and then examined if differences in stand-level habitat structure, nest-patch microhabitat, distance of nests to habitat edges, brood parasitism rates, and nest-predator abundance were potential underlying mechanisms of observed associations between landscape composition and nesting success. We monitored active songbird nests (n = 341), surveyed Brown-headed Cowbirds (Molothrus ater) and nest predators, and measured stand-level and nest-patch microhabitat from May–July 1998 and 1999. Each of 10 study sites was located within contiguous mature forest in central Pennsylvania and contained either agricultural or silvicultural disturbances (n = 5 each). Sites of the two landscape types had similar ranges of disturbance within 1 km (21–55% for agriculture, 18–51% for silviculture). Daily nest survival for all species combined (94.0 ± 0.55 in agriculture and 96.9 ± 0.87 in silviculture) and midstory-canopy nesters (93.8 ± 0.97 in agriculture and 97.4 ± 0.75 in silviculture) were greater within forested landscapes disturbed by silviculture than by agriculture, but rates did not significantly differ between landscapes for ground nesters (92.2 ± 1.32 in agriculture and 94.6 ± 1.63 in silviculture) or understory nesters (95.4 ± 1.60 in agriculture and 95.0 ± 1.47 in silviculture). Nest survival was not significantly associated with disturbance extent. Rates of brood parasitism were low, with only 11% of nests containing cowbird eggs or young. Neither nest fate nor differences in daily nest survival between the two landscape types were explained by variation in brood parasitism rates, stand-level or nest-patch habitat characteristics, or distance of nests to edges. Instead, the lower nest success within forested landscapes disturbed by agriculture was best explained by greater abundances of some avian and small mammalian predators (American Crow [Corvus brachyrhynchos] and squirrels) in those landscapes in one or both years. Results suggest that landscape composition within forested landscapes significantly influences avian nesting success by altering interactions between nest predators and nesting birds.

scholarly journals Habitat preference of the endangered Ethiopian walia ibex (Capra walie) in the Simien Mountains National Park, Ethiopia

2015 ◽  
Vol 38 (1) ◽  
pp. 1-10
Author(s):  
D. Ejigu ◽  
◽  
A. Bekele ◽  
L. Powell ◽  
J.-M. Lernould ◽  
...  
Keyword(s):  
National Park ◽  
Livestock Grazing ◽  
Habitat Characteristics ◽  
Human Populations ◽  
Species Of Conservation Concern ◽  
Pellet Counts ◽  
Predictive Map ◽  
Dry Seasons ◽  
Conservation Concern ◽  
Wet And Dry Seasons

Walia ibex (Capra walie) is an endangered and endemic species restricted to the Simien Mountains National Park, Ethiopia. Recent expansion of human populations and livestock grazing in the park has prompted concerns that the range and habitats used by walia ibex have changed. We performed observations of walia ibex, conducted pellet counts of walia ibex and livestock, and measured vegetation and classified habitat characteristics at sample points during wet and dry seasons from October 2009 to November 2011. We assessed the effect of habitat characteristics on the presence of pellets of walia ibex, and then used a spatial model to create a predictive map to determine areas of high potential to support walia ibex. Rocky and shrubby habitats were more preferred than herbaceous habitats. Pellet distribution indicated that livestock and walia ibex were not usually found at the same sample point (i.e. 70% of quadrats with walia pellets were without livestock droppings; 73% of quadrats with livestock droppings did not have walia pellets). The best model to describe probability of presence of walia pellets included effects of herb cover (β = 0.047), shrub cover (β = 0.030), distance to cliff (β = –0.001), distance to road (β = 0.001), and altitude (β = 0.004). Walia ibexes have shifted to the eastern, steeper areas of the park, appearing to coincide with the occurrence of more intense, human–related activities in lowlands. Our study shows the complexities of managing areas that support human populations while also serving as a critical habitat for species of conservation concern.

Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern

2021 ◽  
pp. 1-16
Author(s):  
Pablo Antúnez ◽  
Christian Wehenkel ◽  
Collins Byobona Kukunda ◽  
José Ciro Hernández-Díaz
Keyword(s):  
Plant Species ◽  
Climatic Variables ◽  
Species Of Conservation Concern ◽  
Conservation Concern

Using impact assessment study designs for addressing impacts to species of conservation concern

2012 ◽  
Vol 36 (3) ◽  
pp. 450-456 ◽  
Author(s):  
Mike E. Marshall ◽  
Ashley M. Long ◽  
Shannon L. Farrell ◽  
Heather A. Mathewson ◽  
Michael L. Morrison ◽  
...  
Keyword(s):  
Impact Assessment ◽  
Impact Assessment Study ◽  
Assessment Study ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Study Designs

scholarly journals White-nose syndrome-related changes to Mid-Atlantic bat communities across an urban-to-rural gradient

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sabrina Deeley ◽  
Joshua B. Johnson ◽  
W. Mark Ford ◽  
J. Edward Gates
Keyword(s):  
The United States ◽  
Myotis Lucifugus ◽  
National Capital Region ◽  
Conservation Areas ◽  
White Nose Syndrome ◽  
Species Of Conservation Concern ◽  
National Capital ◽  
Park Service ◽  
Bat Conservation ◽  
Conservation Concern

Abstract Background White-nose Syndrome (WNS) has reduced the abundance of many bat species within the United States’ Mid-Atlantic region. To determine changes within the National Park Service National Capital Region (NCR) bat communities, we surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. Results The results indicated the continued presence of the threatened Myotis septentrionalis (Northern Long-eared bat) and species of conservation concern, including Perimyotis subflavus (Tri-colored bat), Myotis leibii (Eastern Small-footed bat) and Myotis lucifugus (Little Brown bat). However, we documented a significant reduction in the abundance and distribution of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in the abundance of Eptesicus fuscus (Big Brown bat). Conclusions Documented post-WNS M. septentrionalis recruitment suggests that portions of the NCR may be important bat conservation areas. Decreases in distribution and abundance of P. subflavus and M. lucifugus indicate probable extirpation from many previously occupied portions of the region.

scholarly journals Deep genetic structure at a small spatial scale in the endangered land snail Xerocrassa montserratensis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cristina Català ◽  
Vicenç Bros ◽  
Xavier Castelltort ◽  
Xavier Santos ◽  
Marta Pascual
Keyword(s):  
Genetic Structure ◽  
Land Snail ◽  
Snail Species ◽  
Small Spatial Scale ◽  
Geographic Ranges ◽  
Genetic Groups ◽  
Species Of Conservation Concern ◽  
Conservation Actions ◽  
Conservation Concern ◽  
Single Locality

AbstractSpecies with small geographic ranges do not tend to have a high genetic structure, but some land snail species seem to be an exception. Xerocrassa montserratensis, an endangered land snail endemic to Catalonia (northeastern Iberian Peninsula), is an excellent model to study the processes affecting the phylogeography of specialized species of conservation concern. This species is restricted to xerophilous stony slopes and occurs within a small and fragmented area of ca. 500 km2. We sequenced the COI barcode region of 152 individuals from eight sites covering the entire range of the species. We found four genetic groups mostly coincident with their geographic distribution: a central ancestral group containing shared haplotypes among five localities and three groups restricted to a single locality each. Two of these derived groups were geographically and genetically isolated, while the third and most differentiated group was not geographically isolated. Geomorphologic and paleoclimatic processes during the Pleistocene can explain the divergence found between populations of this low dispersal species with historical fragmentation and secondary contacts. Nonetheless, recent passive large dispersal through streams was also detected in the central group. Overall, our study uncovered four evolutionary units, partially matching morphologically described subspecies, which should be considered in future conservation actions.

Integrating citizen science and remotely sensed data to help inform time-sensitive policy decisions for species of conservation concern

2019 ◽  
Vol 237 ◽  
pp. 463-469 ◽  
Author(s):  
Ashley M. Long ◽  
Brian L. Pierce ◽  
Amanda D. Anderson ◽  
Kevin L. Skow ◽  
Addie Smith ◽  
...  
Keyword(s):  
Citizen Science ◽  
Remotely Sensed ◽  
Policy Decisions ◽  
Remotely Sensed Data ◽  
Species Of Conservation Concern ◽  
Conservation Concern

scholarly journals Using a capture-recapture approach for modelling the detectability and distribution of Houbara Bustard in southern Tunisia

2011 ◽  
Vol 22 (3) ◽  
pp. 288-298 ◽  
Author(s):  
M. CHAMMEM ◽  
S. SELMI ◽  
T. KHORCHANI ◽  
S. NOUIRA
Keyword(s):  
Regression Analyses ◽  
Species Occurrence ◽  
Imperfect Detection ◽  
Southern Tunisia ◽  
Species Of Conservation Concern ◽  
Habitat Factors ◽  
Houbara Bustard ◽  
Capture Recapture ◽  
Conservation Concern ◽  
Free Ranging

SummaryModelling the distribution of species of conservation concern is an important issue in population ecology. Classically, logistic regression analyses are conducted to estimate species’ distributions from detection/non-detection data in a sample of sites and to test for the significance of several environmental variables in predicting the probability of occurrence. These modelling approaches assume that species detection probability is constant and equals one in all sampled sites, which is critical, notably in the case of rare, shy and cryptic species. The capture-recapture-like approach developed by Mackenzie et al. (2002, 2003) provides a reliable tool that accounts for imperfect detection when estimating species occurrence, as well as for assessing the relevance of site features as predictors of species occurrence probability. The aim of this study was to explore the possibility of using this approach in the context of Houbara Bustard Chlamydotis undulata in southern Tunisia. Our results show once more the low detectability of this emblematic species and stress the need to take this factor into account when estimating Houbara spatial distribution. The distribution of Houbara in southern Tunisia is more likely to be shaped by human-related than by habitat factors. In particular, Houbara occurrence was positively associated with site remoteness and camel numbers. Houbara seemed to avoid areas with high human presence and shared the most remote and agriculture-free zones with free-ranging camels.

scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

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