Papers by Gregory Hayward
BioScience, Mar 12, 2015
Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among ... more Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among the highest on Earth, and changes in glacier volume and extent will affect the flow regime and chemistry of coastal rivers, as well as the nearshore marine ecosystem of the Gulf of Alaska. Here we synthesize physical, chemical and biological linkages that characterize the northern PCTR ecosystem, with particular emphasis on the potential impacts of glacier change in the coastal mountain ranges on the surface-water hydrology, biogeochemistry, coastal oceanography and aquatic ecology. We also evaluate the relative importance and interplay between interannual variability and long-term trends in key physical drivers and ecological responses. To advance our knowledge of the northern PCTR, we advocate for cross-disciplinary research bridging the icefield-to-ocean ecosystem that can be paired with long-term scientific records and designed to inform decisionmakers.
This file was created by scanning the printed publication. Errors identified by the software have... more This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain.
The success of habitat monitoring programs depends, to a large extent, on carefully selecting key... more The success of habitat monitoring programs depends, to a large extent, on carefully selecting key habitat attributes to monitor. The challenge of choosing a limited but sufficient set of attributes will differ depending on the objectives of the monitoring program. In some circumstances, such as managing National Forest System lands for threatened and endangered species, habitat monitoring may focus on tracking habitat for one or a few emphasis species. In other settings, such as monitoring the effects of broad-scale land management plans, habitat monitoring may need to address many species. Regardless of scope, similar processes are used to identify attributes for monitoring. The complexity of the organizational and analytical task, however, will differ significantly with scope. In this chapter, we describe steps for choosing habitat attributes for monitoring and for reducing the list of key habitat attributes to those that are affected by management and can be feasibly measured. In...
The Journal of Wildlife Management, 2015
ABSTRACTThe brown bear population on the Kenai Peninsula, Alaska, has not been empirically estima... more ABSTRACTThe brown bear population on the Kenai Peninsula, Alaska, has not been empirically estimated previously because conventional aerial methods over this heavily forested landscape were infeasible. We applied a rapid field protocol to a DNA‐based, mark‐recapture approach on a large and tightly bounded sample frame to estimate brown bear abundance. We used lure to attract bears to barbed wire stations deployed in 145 9‐km × 9‐km cells systematically distributed across 10,200 km2 of available habitat on the Kenai National Wildlife Refuge and Chugach National Forest during 31 consecutive days in early summer 2010. Using 2 helicopters and 4 2‐person field crews, we deployed the stations during a 6‐day period and subsequently revisited these stations on 5 consecutive 5‐day trap sessions. We extracted DNA to identify individual bears and developed capture histories as input to mark‐recapture models. Combined with data from radio‐telemetered bears, ≥243 brown bears were alive on the Ke...
Wildlife Society Bulletin
We examined the efficacy of employing a track-count index to monitor trends in abundance of the A... more We examined the efficacy of employing a track-count index to monitor trends in abundance of the Amur tiger (Panthera tigris altaica) in the Russian Far East. Conservation of the Amur tiger depends upon region-specific information regarding population trends. A traditional tiger census technique has inherent logistical and theoretic constraints, but a logistically feasible and statistically rigorous alternative compatible with the historic tradition of winter track counts has not yet been developed. We used data collected during 434 surveys of foot routes conducted from 1995-1999 to examine characteristics of track counts that will influence monitoring design. Longevity of tiger tracks in snow was 7-8 days in January and February but only an average of 2 days in March. Route length and days since last snow were the 2 most significant design variables explaining variability in detection rate of tracks on survey routes. Variation in track counts observed from foot surveys 0.5 to 28 km ...
BioScience, 2015
Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among ... more Rates of glacier mass loss in the northern Pacific coastal temperate rainforest (PCTR) are among the highest on Earth, and changes in glacier volume and extent will affect the flow regime and chemistry of coastal rivers, as well as the nearshore marine ecosystem of the Gulf of Alaska. Here we synthesize physical, chemical and biological linkages that characterize the northern PCTR ecosystem, with particular emphasis on the potential impacts of glacier change in the coastal mountain ranges on the surface-water hydrology, biogeochemistry, coastal oceanography and aquatic ecology. We also evaluate the relative importance and interplay between interannual variability and long-term trends in key physical drivers and ecological responses. To advance our knowledge of the northern PCTR, we advocate for cross-disciplinary research bridging the icefield-to-ocean ecosystem that can be paired with long-term scientific records and designed to inform decisionmakers.
Wiens/Historical Environmental Variation in Conservation and Natural Resource Management, 2012
Wiens/Historical Environmental Variation in Conservation and Natural Resource Management, 2012
Historical ecology has influenced land-management decisions for decades. An enlightened paper by ... more Historical ecology has influenced land-management decisions for decades. An enlightened paper by Aldo Leopold in 1924 used key observations from historical ecology to develop insights regarding management of grazing and fire in Arizona (Leopold 1924). More recently, the US Forest Service (Forest Service Handbook 1909.12 _40_43) and National Park Service (Unnasch et al. 2009), who manage a significant portion of the public land in North America, formalized the use of historical ecology in planning. The scientific literature ...
Hayward and Iverson "Long-term trend in marbled murrelets in Southeast Alaska based on Chris... more Hayward and Iverson "Long-term trend in marbled murrelets in Southeast Alaska based on Christmas Bird Counts." Northwest Science. 1998; 72(3): 170-179
Forest Ecology and Management, 2015
Extensive ecological disturbances can interact with spatial heterogeneity produced by previous di... more Extensive ecological disturbances can interact with spatial heterogeneity produced by previous disturbances, influencing responses of vertebrates to environmental change. Recent and ongoing outbreaks of bark beetles (including Dendroctonus spp. and Dryocoetes confuses) in the Rocky Mountains produced an opportunity to investigate effects of broad-scale tree mortality on an important seed predator in Nearctic coniferous forests, the red squirrel (Tamiasciurus hudsonicus), and to evaluate whether those effects interact with forest heterogeneity produced by previous timber harvest. Our study characterized site occupancy dynamics for red squirrels in relation to patch-cutting, a type of group-selection cut, and the bark-beetle outbreak, and evaluated whether patch cutting influenced subsequent effects of bark beetles on these squirrels. We used multi-season occupancy models and covariates for harvest-and outbreak-related habitat characteristics to describe extinction and colonization rates of red squirrels over a 27-yr period in Wyoming, USA. We observed effects of year, patch-cutting, and the bark beetle outbreak on the probability of detecting a red squirrel. We observed a negative association between local extinction rate and increasing snag density, but only to a threshold of 5 snags/0.04 ha. Local colonization rate was positively associated with the basal area of live trees. Annual site occupancy varied across years (range pre-harvest: 0.76-0.89; post-harvest: 0.84-0.99), and was lowest (0.70-0.72) during the two years sampling occurred approximately 14 years after the bark beetle outbreaks began. Tree mortality was lowest near patch cuts; this pattern was especially pronounced for mature trees (>30 cm diameter at breast height), which tend to produce the most cones and would likely contribute the most to red squirrel survival. Strong habitat effects on occupancy dynamics suggest that previously-harvested areas may provide refugia for red squirrels in post-outbreak forests. Our results support managing for unevenaged stands of mixed species composition in subalpine forests of the Rocky Mountains.
... (1986) and Mclntire and Carey (1989). Algal cells were compared to fiesh specimens of the com... more ... (1986) and Mclntire and Carey (1989). Algal cells were compared to fiesh specimens of the common Bryr)rla species from the study area (Hayward and Rosentreter 1994). A\l BDoriq specres contained the algal genus Trebouxiq. ... Wesley Colgan III. and Michael Castellano. ...
The Journal of Wildlife Management, 1992
... We recorded nest site occupancy and productivity as measures of foraging habitat trend. ... 1... more ... We recorded nest site occupancy and productivity as measures of foraging habitat trend. ... 1986, Korpimaki 1988, Hayward 1989). In each study, the number of owl nests declined in years of reduced prey abundance (indexed using yearly small mammal trapping). ...
Journal of Mammalogy, 1994
ABSTRACT We examined the composition of nest material used by northern flying squirrels (Glaucomy... more ABSTRACT We examined the composition of nest material used by northern flying squirrels (Glaucomys sabrinus) occupying artificial nest boxes in central Idaho and western Montana. Nests were constructed almost entirely of arboreal lichens (96% lichen by volume). In both regions, three species of Bryoria dominated nesting material although a total of 15 species of lichens were identified in 159 nest samples from central Idaho. Species of lichens used for nests differed across four types of forest vegetation. Nests in stands of lodgepole pine (Pinus contortd) had more Bryoria fremontii and less B. pseudofuscescens than nests in other forest types. The rank-order abundance of lichens used in nests was related to the rank-order abundance of lichens collected from forests at nest sites, although the relationship was not strong. We suggest that lichen nests may function to reduce thermal energy expenditures during winter or act as food caches. The dominant lichen used in nests lacked acids and other secondary compounds found in other arboreal lichens and, thus, may be more palatable to squirrels.
Journal of Freshwater Ecology, 2002
ABSTRACT We estimated consumption of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) b... more ABSTRACT We estimated consumption of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) by resident terrestrial predators and human anglers to place into context the potential predatory impact of exotic lake trout (Salvelinus namaycush) in Yellowstone Lake, Yellowstone National Park, Wyoming, USA. Estimates of consumption rates of piscivorous birds and mammals from the literature were combined with recent estimates of abundance of these predators in the park. Angling mortality was estimated by creel surveys from park management records. Results from a demographic model were used to estimate population size and age distribution of the cutthroat trout population. We estimated that terrestrial predators consumed approximately 7% of the trout population in the lake; angler mortality represented only 1–4% of the adult population. Piscivorous birds accounted for most (99%) of predator mortality, which was focused largely on juvenile trout. American white pelicans (Pelecanus erythrorhynchos) and grizzly bears (Ursus arctos) ate an estimated 5% of the adult trout spawning in streams. Depending on the ultimate size of the lake trout population, predation by introduced lake trout is expected to increase juvenile mortality by 13–67%. Consumption of young adult cutthroat trout by a large population of lake trout would effectively increase angling mortality by 50%. The resulting decline in the native cutthroat trout population is projected to have a significant effect on piscivorous birds, mammalian carnivores, and anglers in Yellowstone National Park.
Journal of Applied Ecology, 2007
Biological Invasions, 2002
Introductions of exotic species pose a significant threat to the persistence of many native popul... more Introductions of exotic species pose a significant threat to the persistence of many native populations, including many inland fishes. In 1994, piscivorous lake trout (Salvelinus namaycush) were discovered in Yellowstone Lake, Yellowstone National Park, Wyoming, USA, one of the last strongholds of the native Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri). Predation by lake trout is expected to lead to a
Ecological Applications, 1996
The supertanker Exxon Valdez ran aground on 24 March 1989, spilling 41 × 106 L of oil into Prince... more The supertanker Exxon Valdez ran aground on 24 March 1989, spilling 41 × 106 L of oil into Prince William Sound, Alaska. To examine effects of this oil spill on the marine bird community, we analyzed data from 11 survey cruises between June 1989 and August 1991. Cruises were conducted in 10 study bays differing in the magnitude of initial oiling. We gauged bird responses to the spill in terms of habitat use, measured by frequency of bay occupancy and species abundances as functions of initial bay oiling. We focused on community‐level measures to obtain a broader perspective than can be obtained from studies directed toward individual species of concern. Effects of the oil spill on community measures were most apparent shortly after the spill but diminished rapidly. Species richness was significantly lower in 1989 than at the same season 1‐2 yr later, especially in heavily oiled bays. Species diversity (log‐series α) was also significantly reduced in more heavily oiled bays in early ...
This file was created by scanning the printed publication. Errors identified by the software have... more This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain.
We collected nesting data on bird use of aspen stands in the Routt and Medicine Bow National Fore... more We collected nesting data on bird use of aspen stands in the Routt and Medicine Bow National Forests between 1987 and 1989. We found active nest sites of 28 species of small nongame birds on nine study plots in undisturbed aspen forests. We compared logistic regression models predicting nest success (at least one nestling) from nest-site or stand-level habitat predictors. Most common species used nest sites in aspen trees in forest interior locations (distance to edge >100 m), with dense trees (opening >100 m away) despite no apparent positive correlation with use of these habitat features and nest success rates. Further investigation may demonstrate that these forest interior sites do not experience lower predation and cowbird parasitism rates than nest sites near openings. We recommend adaptive management experimental treatments, including carefully planned cutting and controlled burns, that should benefit most birds in western aspen forests.
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Papers by Gregory Hayward