Browsing by Subject "Home range"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Management and conservation implications of Blakiston's fish owl (Ketupa blakistoni) resource selection in Primorye, Russia.
    (2011-08) Slaght, Jonathan C.
    The Blakiston's fish owl (Ketupa blakistoni) is a large owl associated with riparian old-growth forests in northeast Asia. Despite its status as a charismatic endangered species, specific conservation and management efforts for the species in Russia are limited. This is because resource use by these secretive owls is poorly known. To address this information deficit, I analyzed resource selection by these owls within a 20,213 km2 study area in Primorye, Russia. Resource selection studies often begin by defining the spatial extent of a home range and then quantifying use of available resources within that home range. For animals that use habitat that are defined by linear environmental features, such as Blakiston's fish owl, traditional home range estimators often overestimate home range size, which can lead to spurious conclusions about resource availability and selection. I used a synoptic model of space use to define Blakiston's fish owl seasonal and annual home range size and within-home range resource selection, and compared results to traditional home range estimators. I also examined nest tree and foraging site selection at 14 nest and 14 foraging sites using linear discriminant analysis. I then identified areas with the highest predicted probability of use by owls to prioritize areas for conservation and management. Fish owl home range was different among most seasons, and estimated home range sizes based on the synoptic model were more biologically-realistic than kernel density-based home range estimators. Mean annual home range size (± standard error) for all fish owls was 15.0 ± 3.7 km2 (n = 7) using the synoptic model, and 38.8 ± 15.4 km2 using kernel density estimators. By season, winter home range was 7.0 ± 3.3 km2 vs. 5.9 ± 2.3 km2 (n = 3 owls; synoptic model vs. kernel density estimator); in spring 13.9 ± 5.2 km2 vs. 29.5 ± 20.4 km2 (n = 7); in summer 11.6 ± 2.8 km2 vs. 33.2 ± 11.9 km2 (n = 6); and in autumn 25.2 ± 13.4 km2 vs. 85.1 ± 56.0 km2 (n = 5). Fish owls selected home ranges that were within valleys, were close to water, and had a greater number of river channels than available sites. Old trees and riparian old-growth forest were the primary discriminating characteristics at both nest and foraging sites, respectively. Large trees were likely necessary as owl nest sites because of the bird's large body size. Moreover, old forests have many large trees that facilitated recruitment of large woody debris in rivers, which created suitable habitat for the owl's primary prey: salmonid fish. Based on resource selection functions I predicted that 54 fish owl territories could occur within my study area. I found that the reserve network contained only 21% of primary fish owl habitat and potentially contained only 7 fish owl territories. I also found that 39% of primary habitat was within current logging leases, which was capable of supporting habitat equivalent to 18 fish owl territories. The remainder of primary habitat (40%) was on federal land not presently protected or within logging leases, and potentially contained 29 fish owl territories. The current protected area network, by itself, will be insufficient to conserve fish owls because so few owl territories are actually protected. Therefore, I developed specific conservation recommendations within logging leases based on the observed resource selection patterns by the owls. My recommendations include protecting specific locations within potential territories, maintaining integrity of riparian areas, modifying road construction techniques, and closing old logging roads to reduce human access. These simple measures have the potential not only to conserve fish owls but also many other species, making this owl an effective umbrella species for the riparian ecosystems of the region.
  • Thumbnail Image
    Item
    Space use behavior and multi-scale habitat selection of American marten (Martes americana) in northeastern Minnesota
    (2013-10) Joyce, Michael James
    Track counts and anecdotal reports indicate that the American marten population in Minnesota has declined over the past 10 years. We deployed radiocollars on 170 marten from 2008-2012 and used location data to describe space use behavior, estimate home range size, and assess habitat selection at landscape and stand scales. Marten selected mature forest, but individual marten showed preference for different forest cover types. Rest sites and reproductive dens facilitate recruitment and protect marten from predators and inclement weather during periods of inactivity. We located 200 rest sites and 31 reproductive dens and measured vegetative characteristics at 31 reproductive dens, 62 rest sites, and 102 random sites. Marten selected dens and rest sites in mature, structurally complex forest stands. Collectively, our results suggest that forest management practices aimed at supporting marten populations should retain stands of mature, structurally complex forest to maintain suitable habitat across the landscape.
  • Thumbnail Image
    Item
    Sport Fish Behavioral Responses to a Littoral Coarse Woody Habitat Addition in a North-temperate Lake
    (2021-05) Smith, Quinnlan
    The availability of suitable habitat throughout an ecosystem is important for the long-term sustainability of natural resources. Coarse woody habitat (CWH) littoral zone additions to north-temperate glacial lakes in the Midwestern United States have become popular to mitigate the effects of increased and intensified lakeshore residential development (LRD) and associated removals of natural CWH. Relatively few of these CWH additions have been treated as deliberate experiments regarding fish and aquatic ecosystem responses. Whole-lake CWH removal experiments have shown detrimental effects on fishes that use the habitat for foraging, refuge, and spawning. Whole-lake CWH additions that have been treated as deliberate experiments have shown increased availability and diversity of prey available to fishes as well as pronounced behavioral changes; however, many of these studies have only focused on singular behavioral responses in singular species and in simple fish communities. To address questions of multiple fish behavioral responses in a complex fish community to CWH addition, a long-term study was initiated on Sanford Lake, Vilas County, Wisconsin, where 160 trees were added to the littoral zone of the lake in summer 2018. I tested for behavioral responses in muskellunge (Esox masquinongy), smallmouth bass (Micropterus dolomieu), and walleye (Sander vitreus) to this CWH addition. To test for behavioral responses to CWH addition, I used radio telemetry data to estimate home range changes, and passive integrated transponder (PIT) data along with radio telemetry data to estimate movement rates between habitats in muskellunge, smallmouth bass, and walleye during pre-manipulation (2017) and post-manipulation (2018 and 2019) time periods. Across species, home ranges and movement rates between habitats increased following the large-scale CWH addition. In the following chapters, I show that complex, species-specific behavioral responses to CWH addition can be expected, and should be taken into consideration before implementing littoral habitat enhancements in diverse fish communities.
  • Thumbnail Image
    Item
    Using GPS Radiotelemetry Locations to Interpret Road and Trail Use by Canada Lynx (Lynx canadensis) in Minnesota
    (2016-12) Terwilliger, Lauren
    The continental United States, including Minnesota, represents the southern extent of the Canada lynx (Lynx canadensis) range. Based on 6 years of radiotelemetry data for lynx in the Superior National Forest, I examined methods for addressing data gaps common to GPS monitoring of free-ranging animals, and examined the use of road infrastructure by lynx within their home ranges. I found that the midpoint between successful locations more accurately estimated the position and cover type of missed locations than imputation using known movement angles and distances. Based on 4,500 GPS locations from 7 individuals, I also found that 3% of lynx locations within seasonal home ranges occurred on roads and trails and lynx crossed road features about 3 times/day. When compared to random locations, lynx were not closer to road infrastructure at the home range scale, but may have been selecting for road infrastructure within 50 m of road features.