Sumatra to Southeast Alaska

Dr. Pyare will talk about his 5-month U.S.Fulbright research experience to Indonesia this past November thru April, the timing of which coincided with the remarkable migration of a ‘local’ seabird, the Aleutian tern, from its spring breeding grounds in Yakutat and other parts of Alaska to the coastal waters of Indonesia (and back again). He will present how the Aleutian tern represents not just a story about the plight of the ocean environment and seabirds, but rather is a global messenger revealing some very fundamental and positive lessons about human society and outlook, regardless of the place we call home

Site-Occupancy Monitoring Of An Ecosystem Indicator: Linking Characteristics Of Riparian Vegetation To Beaver Occurrence

Establishment of sampling frameworks to monitor the occurrence of ecological indicators and to identify the covariates that influence occurrence is a high-priority need for natural resource restoration and management efforts. We utilized occupancy modeling to identify patterns of beaver occurrence and factors influencing these patterns (i.e., type and amount of vegetation cover) in the Grand Canyon of the Colorado River ecosystem. We used rafts and kayaks to access a stratified random sample of sites (i.e., 100-m-long sections of riverbank) and used repeated sampling procedures to sample for beaver sign (i.e., lodges, cuttings, tracks, and beaver sightings). We quantified the type and amount of vegetation cover at each sampled section by using a GIS database of remotely sensed information on the riparian vegetation in the Grand Canyon. We first modeled occurrence of beaver sign as a function of the total amount of vegetation cover (summed across classes) and then determined the relative importance score for each of the 7 vegetation classes. Detection probability (p) was 2 times higher when observers traveled in kayaks (0.61) than when they traveled in rafts (0.29). Occurrence of beaver sign (ψ) in sampled transects was widespread throughout the Grand Canyon (ψ = 0.74, SE = 0.06) and positively associated with total vegetation. The relative importance scores for Tamarix and Pluchea vegetation classes were 1.5–2.5 times larger than those for all other vegetation classes, indicating that occurrence of beaver sign was most strongly associated with the cover of these 2 vegetation classes. Our results imply that quantifying the amount of riparian vegetation in close proximity to a river helps determine the occurrence of an important ecological indicator in riparian systems. The results also demonstrate a useful and cost-effective method for monitoring riverine species’ usage patterns by explicitly accounting for detectability

Interrelationships among northern flying squirrels, truffles, and microhabitat structure in Sierra Nevada old-growth habitat

During 1997-1998, we investigated the influence of both the relative abundance of truffles, preferred food items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in old-growth forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor for truffle diggings and sampled the soil for truffles. Diggings were more abundant where flying squirrels were captured, suggesting squirrels were active near areas of the forest floor where truffles had recently been excavated. The frequency of sampling plots with truffles was higher where squirrels were captured, further suggesting preferences for microhabitats where truffles were more abundant. We also measured 15 microhabitat variables at trap stations to evaluate the influence of aboveground microhabitat characteristics on squirrel occurrence. Results indicated that flying squirrels preferred microhabitats with understory cover, which may minimize predation from aerial predators like spotted owls (Strix occidentalis Merriam). Neither abundance of coarse woody debris, a feature conducive to fungal growth, nor the abundance of potential nesting sites (i.e., snags) measurably influenced squirrel occurrence. While various aboveground forest-microhabitat characteristics affect the use of old-growth forests by flying squirrels, these animals refine their use of these forests based on fine-scale changes in the availability of a highly preferred and ephemeral food item. </jats:p

Mechanisms of truffle detection by northern flying squirrels

The objective of this study was to evaluate how northern flying squirrels (Glaucomys sabrinus) locate truffles (Gautieria monticola), a subterranean and ephemeral but primary food source. Thus, we evaluated the importance of three factors to the foraging behavior of northern flying squirrels: (i) olfactory chemicals that emanate from truffles; (ii) the presence of coarse woody debris (decaying logs), which are often associated with fungi; and (iii) we explored the potential role animal memory could play in truffle detection as well. In a foraging arena, squirrels successfully retrieved buried truffles that lacked aboveground cues in 19 of 30 trials and failed to search near treatments that lacked truffles altogether, confirming the importance of olfaction to squirrel foraging. However, squirrels also retrieved truffles that were associated most frequently with surface logs (27 of 30). In addition, the initial detection rate of the truffle + log treatment was significantly greater than the truffle-only treatment. Thus, although squirrels search for truffles primarily using olfaction, they may also benefit by searching near coarse woody debris on the forest floor as an aboveground cue to truffle locations. In addition, because 82% of Sierra Nevada truffle-fruiting locations that were marked in 1996 yielded truffles again the following 2 years, mycophagous animals like northern flying squirrels may benefit by memorizing fruiting locations and foraging at these same locations from year to year. </jats:p

Interrelationships among northern flying squirrels, truffles, and microhabitat structure in Sierra Nevada old-growth habitat

During 1997–1998, we investigated the influence of both the relative abundance of truffles, preferred food items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in old-growth forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor for truffle diggings and sampled the soil for truffles. Diggings were more abundant where flying squirrels were captured, suggesting squirrels were active near areas of the forest floor where truffles had recently been excavated. The frequency of sampling plots with truffles was higher where squirrels were captured, further suggesting preferences for microhabitats where truffles were more abundant. We also measured 15 microhabitat variables at trap stations to evaluate the influence of aboveground microhabitat characteristics on squirrel occurrence. Results indicated that flying squirrels preferred microhabitats with understory cover, which may minimize predation from aerial predators like spotted owls (Strix occidentalis Merriam). Neither abundance of coarse woody debris, a feature conducive to fungal growth, nor the abundance of potential nesting sites (i.e., snags) measurably influenced squirrel occurrence. While various aboveground forest-microhabitat characteristics affect the use of old-growth forests by flying squirrels, these animals refine their use of these forests based on fine-scale changes in the availability of a highly preferred and ephemeral food item

Interrelationships among northern flying squirrels, truffles, and microhabitat structure in Sierra Nevada old-growth habitat

During 1997–1998, we investigated the influence of both the relative abundance of truffles, preferred food items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in oldgrowth forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor for truffle diggings and sampled the soil for truffles. Diggings were more abundant where flying squirrels were captured, suggesting squirrels were active near areas of the forest floor where truffles had recently been excavated. The frequency of sampling plots with truffles was higher where squirrels were captured, further suggesting preferences for microhabitats where truffles were more abundant. We also measured 15 microhabitat variables at trap stations to evaluate the influence of aboveground microhabitat characteristics on squirrel occurrence. Results indicated that flying squirrels preferred microhabitats with understory cover, which may minimize predation from aerial predators like spotted owls (Strix occidentalis Merriam). Neither abundance of coarse woody debris, a feature conducive to fungal growth, nor the abundance of potential nesting sites (i.e., snags) measurably influenced squirrel occurrence. While various aboveground forest-microhabitat characteristics affect the use of old-growth forests by flying squirrels, these animals refine their use of these forests based on fine-scale changes in the availability of a highly preferred and ephemeral food item

Evaluating the accuracy of unmanned aerial systems to quantify glacial ice habitats of harbor seals in Alaska

Abstract Long‐term monitoring programs to evaluate climate‐driven changes to tidewater glaciers, an important habitat for harbor seals (Phoca vitulina) in Alaska, are primarily carried out by costly, weather‐dependent aerial surveys from fixed‐winged aircraft. Unmanned aerial systems (UAS) can be an alternative cost‐effective solution for gathering image data to quantify, monitor, and manage these habitats. However, there is a paucity of information related to the accuracy of using imagery collected by UAS for purposes of measuring floating icebergs. We evaluated the accuracy of using a UAS with a built‐in 20‐megapixel (MP) camera as well as a consumer‐grade digital 16‐MP camera to capture images of floating and stationary icebergs for the purpose of collecting vertical height measurements. Images (n = 869) were captured of simulated icebergs (cuboidal foam boxes, Cb) (n = 5) and real icebergs (n = 5) that were either grounded or floating. The mean error ratios (Ers) obtained were less than 10% and derived by comparing the mean calculated measurements of heights of Cb obtained from images captured by UAS with the physically measured heights of these Cb. The mean Er for height measurements of grounded icebergs (n = 4) and one floating iceberg was also less than 10%. Within an object–image distance range of 6–25 m, the cameras captured images that were suitable to accurately calculate the heights of floating and grounded objects, and drift or uncontrolled movement of the UAS caused by wind or temporary loss of GPS did not have any effect on measurement error. Our study provides substantial evidence of the accuracy associated with using images captured by UAS for measuring dimensions of structures positioned on either water or land surfaces. Ultimately, accurate surveys of glacial ice used by harbor seals will improve our understanding of the role of decreasing habitat in explaining population variability between different tidewater glaciers