Julia Gulka

• Master of Science
• Researcher at Biodiversity Research Institute

Pulsed resources resulting from animal migrations represent important, transient influxes of high resource availability into recipient communities. The ability of predators to respond and exploit these large increases in background resource availability, however, may be constrained when the timing and magnitude of the resource pulse vary across yea...

Offshore wind energy (OSW) development, while a key strategy for reducing global reliance on fossil fuels, nevertheless has environmental effects that should be mitigated. We reviewed the scientific literature and gray literature to identify approaches for mitigating (e.g., avoiding, minimizing, or compensating for) the effects of OSW development o...

Offshore wind energy development (OWED), while a key strategy for reducing carbon emissions, has potential negative effects to wildlife that should be examined to inform decision making and adaptive management as the industry expands. We present a conceptual framework to guide the long-term study of potential effects to birds and bats from OWED. Th...

Mercury (Hg) inputs have particularly impacted the northeastern United States due to its proximity to anthropogenic emissions sources and abundant habitats that efficiently convert inorganic Hg into methylmercury. Intensive research and monitoring efforts over the past 50 years in New York State, USA, have informed the assessment of the extent and...

Forage fishes are a critical food web link in marine ecosystems, aggregating in a hierarchical patch structure over multiple spatial and temporal scales. Surface-level forage fish aggregations (FFAs) represent a concentrated source of prey available to surface- and shallow-foraging marine predators. Existing survey and analysis methods are often im...

Resource availability is a key factor driving marine bird movements and distributions, but direct information on prey availability is difficult to obtain at relevant scales. We present novel methods for describing multi-scale trophic associations, combining movement analyses of marine birds with estimates of forage fish surface aggregations from di...

When resources are finite, individuals optimize energy allocation between survival and reproduction to maximize fitness. As food becomes more limited within foraging ranges of breeding colonies, long-lived seabirds are predicted to increase time spent foraging, and chick growth, breeding success and ultimately adult survival, will be reduced. Acros...

The offshore wind (OSW) energy industry is rapidly developing in the United States. New federal mandates require at least 30 GW of OSW by 2030. With the largest goal in the eastern United States, the state of New York seeks to advance OSW in a way that is both environmentally and socially responsible as well as cost‐effective. To achieve this, New...

As the world develops sources of renewable energy, there is an intensifying interest in offshore wind energy production. The Northeast U.S. Continental Shelf (NES) ecosystem has favorable wind dynamics, with active development of wind energy. In this study, we present species distribution models that consider both occupancy and biomass responses fo...

Forage fishes are a critical food web link in marine ecosystems, aggregating in a hierarchical patch structure over multiple spatial and temporal scales. Surface-level forage fish aggregations (FFAs) represent a concentrated source of available prey for surface- and shallow-foraging marine predators. Existing survey and analysis methods are often i...

Territoriality for breeding sites comes at an energetic cost—individuals actively defend the site from competitors and potential predators, thus precluding themselves from self-maintenance (e.g., foraging, preening) or offspring care. Breeding individuals are also constrained to central place foraging within a limited range of the territory. For th...

Density-dependent prey depletion around breeding colonies has long been considered an important factor controlling the population dynamics of colonial animals.1, 2, 3, 4 Ashmole proposed that as seabird colony size increases, intraspecific competition leads to declines in reproductive success, as breeding adults must spend more time and energy to f...

Final workshop proceedings for the 2020 State of the Science Workshop on Wildlife and Offshore Wind Energy

Curtailment of turbine operations during low wind conditions has become an operational minimization tactic to reduce bat mortality at terrestrial wind energy facilities. Site-specific studies have demonstrated that bat activity is higher during lower wind speeds and that operational curtailment can effectively reduce fatalities. However, the exact...

To grow, survive and reproduce under anthropogenic-induced changes, individuals must respond quickly and favourably to the surrounding environment. A species that feeds on a wide variety of prey types (i.e. generalist diet) may be comprised of generalist individuals, specialist individuals that feed on different prey types, or a combination of the...

Blanket curtailment of turbine operations during low wind conditions has become an accepted operational minimization tactic to reduce bat mortality at terrestrial wind facilities. Site-specific studies have demonstrated that operational curtailment effectively reduces impacts, but the exact nature of the relationship between increased cut-in speed...

This report is one outcome from a broader effort to review the state of knowledge regarding offshore wind energy development's effects on wildlife and identify short-term research priorities to improve our understanding of cumulative biological impacts as the offshore wind industry develops in the eastern United States. This effort, titled State of...

This report is one outcome from a broader effort to review the state of knowledge regarding offshore wind energy development's effects on wildlife and identify short-term research priorities to improve our understanding of cumulative biological impacts as the offshore wind industry develops in the eastern United States. This effort, titled State of...

To grow, survive and reproduce under anthropogenic-induced changes, individuals must respond quickly and favourably to the surrounding environment. A species that feeds on a wide variety of prey types (i.e. generalist diet) may be comprised of generalist individuals, specialist individuals that feed on different prey types, or a combination of the...

When breeding within densely populated colonies, seabirds benefit from increased offspring protection from predators, but intraspecific competition for resources may outweigh these benefits. We tested whether the number of breeding-site neighbours and days of predator presence influenced the breeding performance of Common Murres Uria aalge at two d...

Spatial patterns of breeding seabirds are influenced by the distribution of resources in relation to the colony and the density of conspecifics from the same or adjacent colonies. We conducted an inter-colony comparison of foraging space use and behavior, diet, and reproductive success of common murres Uria aalge breeding at a large offshore and a...

Studying the diet of consumers using stable isotopes provides insight into the foraging ecology of individuals and species. To accurately reconstruct the integrated diet of animals using stable isotope values, we must quantify diet-tissue discrimination factors (DTDFs), or the way in which stable isotopes in prey are incorporated into the tissues o...

Rationale: Analysis of the stable isotope ratios of carbon and nitrogen (δ13 C and δ15 N values) is increasingly being used to gain insight into predator trophic ecology, which requires accurate diet-tissue discrimination factors (DTDFs), or the isotopic difference between prey and predator. Accurate DTDFs must be calculated from predators consumi...

Interspecific interactions help to shape individual-and population-level dynamics. As such, similar species breeding sympatri-cally are expected to have a high potential for competition and, thus, may have developed strategies to reduce niche overlap to allow coexistence. We combined GPS tracking and stable isotope analysis (δ 15 N, δ 13 C) to simu...

The foraging ecology of breeding seabirds is largely influenced by prey availability and energy demands related to reproduction which, in combination with other factors, can affect resource specialization in space and time. In this study, we combined GPS tracking, dive behavior, and stable isotope ratios of carbon and nitrogen to examine behavioral...

Gaps exist in our knowledge of the life history of the Vulnerable yelkouan shearwater Puffinus yelkouan, which is endemic to the Mediterranean basin. This work documents the first instance of hand-rearing and translocation of two yelkouan shearwater chicks rescued off the coast of Malta during the 2016 breeding season. The chicks were hand-reared f...

Gaps exist in our knowledge of the life history of the Vulnerable yelkouan shearwater Puffinus yelkouan, which is endemic to the Mediterranean basin. This work documents the first instance of hand-rearing and translocation of two yelkouan shearwater chicks rescued off the coast of Malta during the 2016 breeding season. The chicks were hand-reared f...

Understanding species interactions among top marine predators and interactions with their prey can provide important insight into community-level responses to changing prey availability and the role of apex predators as indicators of ecosystem change. On the northeast Newfoundland coast, marine predators rely on capelin (Mallotus villosus), a domin...

Abstract: On the northeast Newfoundland coast, marine predators rely on capelin (Mallotus villosus), a dominant forage fish, as a food source. Capelin migrate into coastal regions to spawn during July, essentially transforming prey biomass from low (pre-spawning) to high (spawning) for coastal marine predators. During July-August, 2016, we investig...