Fine-Scale Habitat Characteristics Related to Occupancy of the Yosemite Toad,Anaxyrus canorus

Copeia ◽  
2017 ◽  
Vol 105 (1) ◽  
pp. 120-127 ◽  
Author(s):  
Christina T. Liang ◽  
Robert L. Grasso ◽  
Julie J. Nelson-Paul ◽  
Kim E. Vincent ◽  
Amy J. Lind
Evolution ◽  
2019 ◽  
Vol 73 (12) ◽  
pp. 2476-2496 ◽  
Author(s):  
Paul A. Maier ◽  
Amy G. Vandergast ◽  
Steven M. Ostoja ◽  
Andres Aguilar ◽  
Andrew J. Bohonak

PLoS ONE ◽  
2013 ◽  
Vol 8 (8) ◽  
pp. e72200 ◽  
Author(s):  
Eric L. Berlow ◽  
Roland A. Knapp ◽  
Steven M. Ostoja ◽  
Richard J. Williams ◽  
Heather McKenny ◽  
...  

2021 ◽  
Author(s):  
◽  
Samhita Bose

<p>Black-tailed deer (BTD, Odocoileus hemionus columbianus), a socio-economically important deer species in western North America is steadily declining throughout much of its range over the last century. Though a large number of studies have been carried out on forage availability, predation pressure, and population dynamics of the species, there still remain broad gaps in current understanding of the underlying causes, mechanisms, and spatio-temporal patterns of habitat use which can affect the population dynamics and distribution of BTD. So, the central aim of my thesis was to identify the spatial and temporal scale that may affect habitat selection, movement and ultimately long-term persistence of the BTD population in the Mendocino National Forest, California.  Understanding population structuring in BTD is vital to underpin the spatial scale for conservation. So, I tested for presence of population sub-structuring among female BTD in the study area by analysing the combined effect of site fidelity and philopatry on the population. Fidelity analyses from radio-telemetry data revealed BTD to have extremely small seasonal home ranges (0.71 km²) and very high site fidelity to these ranges. Direct fitness benefits of fidelity were observed as individuals with decreased site fidelity to their ranges suffered elevated risks of mortality. Results from mtDNA sequencing revealed high genetic differentiation (FST > 0.30) and low haplotype sharing even among geographic areas separated by as little as 4–10 km. Combined, the results indicated prolonged period of philopatric behaviour resulting in demographic isolation and very small scale population sub-structuring that can impact the population dynamics at a finer spatial scale than previously assumed.  Next, I examined the effect of temporal scale on resource selection by BTD, through comparing habitat characteristics selected by BTD from a pooled model (all telemetry locations pooled across activity states) versus habitat characteristics associated with foraging (active state) and resting or ruminating (inactive state). The main factors that influenced resource selection in BTD were: 1) seasonal changes associated largely with variable selection towards slope, aspect, and elevation and 2) activity states influenced fine-scale selection towards vegetation type, edge density, and cover within the home-ranges. The comparative analysis also revealed that due to larger proportion of resting and ruminating locations, the pooled model frequently failed to identify critical foraging habitats and reflected habitats associated with resting. The frequent misidentification for important ecological covariates associated with foraging was a testimony that pooling data across activity states in BTD can negatively impact our understanding about habitat selection by the species.  Finally, I developed a movement model to understand the spatial and temporal patterns of risk-forage trade-offs by female BTD as a function of landscape familiarity. The results showed that familiarity affects the trade-off patterns by BTD in a heterogeneous landscape, with differential selection towards productivity and risk that also varied largely with habitat types. The results further revealed strong selection towards highly familiar areas by BTD during the night time and at dawn while stepping into less familiar areas during the daytime. The demonstrated preference for familiar locations within their home ranges when their primary predator (puma) is most active emphasizes that spatial familiarity is important not only for large scale processes like selection of home range, but also for striking fine-scale trade-offs between forage and risk within individual home ranges. The knowledge of this fine scale selection pattern is critical for maintaining habitat heterogeneity at a spatial scale comparable to the size of their home ranges, as they have vital consequences on fitness of BTD that ultimately affects the population dynamics of the species.</p>


Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 391
Author(s):  
Maria Eggertsen ◽  
Dinorah H Chacin ◽  
Joshua van Lier ◽  
Linda Eggertsen ◽  
Christopher J Fulton ◽  
...  

Structural complexity spanning fine to broad spatial scales can influence the distribution and activity of key organisms within marine ecosystems. However, the relative importance of hard (e.g., corals) and/or soft (e.g., macroalgae) structural complexity for marine organisms is often unclear. This study shows how both broad-scale (seascape configuration of coral structure) and fine-scale habitat complexity (structure height, number of holes, and presence of macroalgae) can influence the abundance and spatial ecology of reef fish. Underwater visual census of fish, surveys of habitats, remote underwater videos, and behavioral observations by following individual fish were used to quantify fine-scale habitat characteristics (e.g., complexity, coral structure height, macroalgae presence) and the abundance, size structure, and behavior (rates of herbivory, tortuosity ratios and total distance travelled) of abundant parrotfish. Both seascape configuration and macroalgae influenced the patterns of fish abundance and rates of herbivory. However, these relationships varied with trophic groups and ontogenetic stages. Abundance of adult and intermediate-phase parrotfishes was positively influenced by densely aggregated coral structures, whereas juvenile abundance was positively influenced by the presence of macroalgae. Foraging path and bite rates of an abundant parrotfish, Chlorurus spilurus, were not influenced by coral structure configuration or height, but the presence of macroalgae increased the bite rates of all juvenile parrotfish. Our results suggest that a combination of seascape configuration, fine-scale habitat complexity, and microhabitat selectivity influence reef fish community structure and foraging behavior, thus altering herbivory. However, these relationships can differ among functional groups of fish and life-history stages. Information on these fish–habitat interactions is critical for identifying habitats that facilitate ecological functions and ensures the successful management and conservation of essential habitats.


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