Consequences of Multi-Scale Habitat Selection on Reproductive Success of Riverine Sandbar-Nesting Birds in Cambodia

2018 ◽  
Vol 11 (2) ◽  
pp. 108-122 ◽  
Author(s):  
Andrea H. Claassen ◽  
James D. Forester ◽  
Todd W. Arnold ◽  
Francesca J. Cuthbert

Habitat selection occurs at multiple spatial scales and affects demographic processes including reproductive success. Few studies, however, have linked multi-scale habitat selection to reproductive success. We investigated breeding habitat selection at three spatial scales (nest site, nest area and territory), and the consequences of habitat selection on reproductive success of four riverine sandbar-nesting bird species in Cambodia. All species generally selected larger habitat patches, in territories with higher proportions of bare ground substrates, including gravel and dry mud. Individuals generally selected areas with less vegetation; however, at smaller spatial scales, Small Pratincoles (Glareola lactea) and Little Ringed Plovers (Charadrius dubius) used sites with more vegetation. Vegetation generally had a negative effect on reproductive success. For River Terns (Sterna aurantia), nest success was lower in areas with a higher proportion of invasive Mimosa pigra, and chick survival decreased with vegetation height. River Lapwing (Vanellus duvaucelii) nest success decreased with more woody stems, and nest success of Small Pratincoles and Little Ringed Plovers decreased with more herbaceous vegetation. Negative effects of vegetation were likely due to reduced ability of incubating birds to detect predators, or increased cover or foraging efficiency of predators. Finally, proximity to the river channel reduced nest success; nests near the channel had a higher risk of flooding. This is the first study to identify variables associated with habitat selection for all species in this study and to relate habitat use to reproductive success. Results of this study will aid conservation efforts for these regionally threatened species.

2017 ◽  
Vol 27 (4) ◽  
pp. 495-511 ◽  
Author(s):  
ANDREA H. CLAASSEN ◽  
KO SOK ◽  
TODD W. ARNOLD ◽  
FRANCESCA J. CUTHBERT

SummaryDirect payments to communities or individuals have gained traction as a tool for species conservation; however, few studies have evaluated their effectiveness. From 2010 to 2014, we monitored nests and implemented a direct payment nest protection programme for six sandbar-nesting bird species on the Mekong River, Cambodia, and tested if nest protection improved reproductive success. Nests were guarded by community members; additionally, exclosures were used to protect nests of River Tern Sterna aurantia, the species of highest conservation concern. We investigated factors affecting nest and chick survival, and probability of nest failure due to egg harvest or predation. Nesting later in the season generally resulted in lower nest and chick survival. Nest protection improved survival rates of River Tern nests and chicks, and Small Pratincole Glareola lactea nests. River Tern nest success was 60% for exclosed (and guarded) nests, 29% for guarded (but unexclosed) nests, and 5% for unprotected nests. River Tern fledging success was 82% for exclosed chicks, 40% for chicks that were guarded only, and 2% for unprotected chicks. Small Pratincole nest success was 21% for guarded and 6% for unguarded nests. Egg harvest by humans was lower among protected nests and declined during the study. Nest predation by animals increased during the study despite nest guarding; however, predator exclosures effectively protected nests and chicks. Additional predator control measures could further improve reproductive success of sandbar-nesting birds. Overall, nest protection involving direct payments was highly effective, but required diligent use of nest exclosures, frequent monitoring, and strong community relationships.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3164 ◽  
Author(s):  
Jan Jedlikowski ◽  
Mattia Brambilla

BackgroundHabitat selection and its adaptive outcomes are crucial features for animal life-history strategies. Nevertheless, congruence between habitat preferences and breeding success has been rarely demonstrated, which may result from the single-scale evaluation of animal choices. As habitat selection is a complex multi-scale process in many groups of animal species, investigating adaptiveness of habitat selection in a multi-scale framework is crucial. In this study, we explore whether habitat preferences acting at different spatial scales enhance the fitness of bird species, and check the appropriateness of single vs. multi-scale models. We expected that variables found to be more important for habitat selection at individual scale(s), would coherently play a major role in affecting nest survival at the same scale(s).MethodsWe considered habitat preferences of two Rallidae species, little crake (Zapornia parva) and water rail (Rallus aquaticus), at three spatial scales (landscape, territory, and nest-site) and related them to nest survival. Single-scale versus multi-scale models (GLS and glmmPQL) were compared to check which model better described adaptiveness of habitat preferences. Consistency between the effect of variables on habitat selection and on nest survival was checked to investigate their adaptive value.ResultsIn both species, multi-scale models for nest survival were more supported than single-scale ones. In little crake, the multi-scale model indicated vegetation density and water depth at the territory scale, as well as vegetation height at nest-site scale, as the most important variables. The first two variables were among the most important for nest survival and habitat selection, and the coherent effects suggested the adaptive value of habitat preferences. In water rail, the multi-scale model of nest survival showed vegetation density at territory scale and extent of emergent vegetation within landscape scale as the most important ones, although we found a consistent effect with the habitat selection model (and hence evidence for adaptiveness) only for the former.DiscussionOur work suggests caution when interpreting adaptiveness of habitat preferences at a single spatial scale because such an approach may under- or over-estimate the importance of habitat factors. As an example, we found evidence only for a weak effect of water depth at territory scale on little crake nest survival; however, according to the multi-scale analysis, such effect turned out to be important and appeared highly adaptive. Therefore, multi-scale approaches to the study of adaptive explanations for habitat selection mechanisms should be promoted.


2020 ◽  
Vol 6 (1) ◽  
pp. 24-40
Author(s):  
Philippe Galipeau ◽  
Alastair Franke ◽  
Mathieu Leblond ◽  
Joel Bêty

Raptors are important environmental indicators because they are apex predators and can be sensitive to disturbance. Few studies have addressed habitat preferences of tundra-nesting raptors, and those that exist have focused on fine-scale characteristics. With increasing economic development predicted to occur throughout the Canadian Arctic, the investigation of raptor breeding habitat at broad spatial scales is required. We modeled breeding habitat selection for two raptor species on north Baffin Island, NU, Canada. During aerial surveys conducted over six breeding seasons, we documented 172 peregrine falcon (Falco peregrinus tundrius) and 160 rough-legged hawk (Buteo lagopus) nesting sites. We used these locations in conjunction with remote sensing data to build habitat selection models at three spatial scales. Topography, distance to water, and normalized difference vegetation index explained selection at all scales; slope aspect was also important at the finest scale. To validate landscape scale models, we conducted a validation survey that resulted in the detection of 45 new nests (peregrine falcon n = 21, rough-legged hawk n = 24). We did not detect any new nests in areas where model-predicted occurrence was expected to be low. Conversely, we found more than half of previously undetected nests in areas where model-predicted occurrence was expected to be high.


The Condor ◽  
2020 ◽  
Vol 122 (1) ◽  
Author(s):  
Courtney J Duchardt ◽  
Jeffrey L Beck ◽  
David J Augustine

Abstract Habitat loss and altered disturbance regimes have led to declines in many species of grassland and sagebrush birds, including the imperiled Mountain Plover (Charadrius montanus). In certain parts of their range Mountain Plovers rely almost exclusively on black-tailed prairie dog (Cynomys ludovicianus) colonies as nesting habitat. Previous studies have examined Mountain Plover nest and brood survival on prairie dog colonies, but little is known about how colony size and shape influence these vital rates or patterns of habitat selection. We examined how (1) adult habitat utilization, (2) nest-site selection, and (3) nest success responded to a suite of local- and site-level variables on large prairie dog colony complexes in northeastern Wyoming. Abundance of adult Mountain Plovers was highest on points within older, “medium”-sized (100–500 ha) colonies with high cover of annual forbs and bare ground (5.8 birds km−2), but lower on extremely large (>2,000 ha) colonies (2.1 birds km−2). Nest sites were characterized by high proportions of annual forbs and bare ground and low cactus cover and vegetation height. Nest survival was higher for older nests, and nests with lower cactus cover, and decreased with increasing temperatures. Uncertainty was high for models of daily nest survival, potentially because of 2 competing sources of nest failure: nest depredation and nest abandonment or inviability of eggs. Drivers of these 2 sources of nest failure differed, with inclement weather and higher temperatures associated with nest abandonment or egg inviability. We highlight how prairie dogs alter vegetation structure and bare ground heterogeneously across the landscape, and how this in turn influences bird abundance and nest distribution at different temporal and spatial scales. Furthermore, our work reveals how partitioning the causes of nest failure during nest survival analyses enhances understanding of survival rate covariates.


Ecology ◽  
2017 ◽  
Vol 98 (10) ◽  
pp. 2684-2697 ◽  
Author(s):  
Paul Acker ◽  
Aurélien Besnard ◽  
Jean-Yves Monnat ◽  
Emmanuelle Cam

2016 ◽  
Vol 27 (3) ◽  
pp. 398-413 ◽  
Author(s):  
CRISTIAN PÉREZ-GRANADOS ◽  
GERMÁN M. LÓPEZ-IBORRA ◽  
JAVIER SEOANE

SummaryHabitat selection of endangered species in peripheral populations must be considered when designing effective conservation plans, as these populations tend to occupy atypical habitats where species-environment relationships are not well understood. We examined patterns of habitat use in peripheral populations of the endangered Dupont’s Lark Chersophilus duplonti using a multi-scale approach and assessed the spatiotemporal transferability of these models to test for their generality. Our results show that at microhabitat (circles of 50-m diameter used by the species versus random points) and macrohabitat (occupied/unoccupied squares of 1 ha) scales the species selected flat and non-forested areas, but at the microhabitat scale the cover of small shrubs was also important. Models developed at patch scale (occupied /unoccupied sites) identified only site size as an important predictor of species occurrence. Habitat models transferred successfully among sites and years, which suggests that these models and our recommendations may be extrapolated over a larger geographic area. A multi-scale approach was used for identifying conservation requirements at different spatial scales. At the patch scale our models confirm it is a priority to maintain or enlarge the extent of habitat patches to ensure the viability of the studied metapopulation. At the macrohabitat scale our results suggest that reducing tree density in low slope areas would be the most effective management action. At the microhabitat scale, encouraging the presence of small and medium-sized shrubs, by clearing certain scrubs (e.g. large brooms Genista spp. and rosemary Rosmarinus officinalis) or promoting traditional low-level extensive grazing, should increase the availability of high-quality habitats for the species, and thus the number of potential territories within a patch. These recommendations largely coincide with the ones given for core populations at specific scales elsewhere.


2010 ◽  
Vol 16 (1) ◽  
pp. 27 ◽  
Author(s):  
D. L. Oliver ◽  
G. W. Lollback

This is the first Australian study to apply logistical modelling techniques to describe the breeding habitat selection of a widely dispersed, highly mobile, threatened bird species. Landscape and microhabitat structural attributes of breeding habitat occupied by the endangered Regent Honeyeater Anthochaera phrygia in the Bundarra-Barraba region of northern NSW were compared to those of unoccupied habitat using logistic regression modelling. Models containing landscape scale variables were best at explaining Regent Honeyeater presence. Regent Honeyeater occupation was negatively associated with the amount of woodland cover surrounding a site (1 km and 2 km radius) and distance to patch edge, and was positively associated with site connectivity and linear remnants. Linear, well-connected woodland patches surrounded by cleared grazing land are typical of the remnant native vegetation occupied by Regent Honeyeaters in the Bundarra-Barraba region. The landscape models developed here can be used to identify potential new sites for protection and rehabilitation, and to assess the suitability of unsurveyed or unoccupied sites for the release of captively bred Regent Honeyeaters, which is identified as one of the priority recovery action for the species.


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