Climate change effects on Upper Kobuk River aquatic ecosystems, Gates of the Arctic National Park and Preserve Developing a Conceptual Model.DOC

Climate change effects on Upper Kobuk River aquatic ecosystems, Gates of the Arctic National Park and Preserve: Developing a Conceptual Model Proposal date: June 2.. Moyle Professor, Wil

Climate change effects on Upper Kobuk River aquatic ecosystems, Gates of the Arctic National Park and Preserve: Developing a Conceptual Model

Proposal date: June 2 2008

Principal investigators:

Jeffrey F Mount

Professor, Geology

Director, Center for Watershed Sciences

University of California

1 Shields Avenue

Davis Ca 95616

Tel: 530-754-9388

Fax: 530-752-0951

mount@geology.ucdavis.edu

Peter B Moyle

Professor, Wildlife, Fish, and Conservation Biology

Associate Director, Center for Watershed Sciences

University of California

1 Shields Avenue

Davis Ca 95616

Tel: 530-752-6355

Fax: 530-752-4154

pbmoyle@ucdavis.edu

Abstract: We propose to develop and assess a conceptual model for the effects of climate

change on aquatic ecosystems of the Upper Kobuk River, Alaska, with an emphasis on foodwebs A field assessment of the model will be performed as the final project for an interdisciplinary class of UC Davis graduate students Field study of the Kobuk River will take place from August 11 -23 and will begin at the outlet of Walker Lake and end at the town of Kobuk The trip will involve 10 students, two professors and two guides During class meetings in April, May, and early June, a conceptual model of the Upper

Kobuk/Walker Lake aquatic ecosystems will be developed based on the literature The model will focus on the likely responses of aquatic food webs to changes in habitat

associated with climate-driven shifts in runoff, temperature, nutrient cycling, and

geomorphology During field study the basic premises of the model will be evaluated and, where appropriate, tested on the river Two days will be spent sampling water quality, plankton and fish on Walker Lake Within the reach of river from Walker Lake to Kobuk a minimum of 20 sites will be surveyed over the course of 10 days Based on a stratified sampling approach within three river segments, approximately 10 of the sites will be along the mainstem of the river and 10 of the sites will be at tributary/mainstem confluences Each sample site will be georeferenced and mapped to record type and distribution of habitats and geomorphic conditions We will use rapid bioassessment procedures to sample water quality, fishes and aquatic invertebrates (where feasible) to determine basic species composition in representative shallow water areas Based on the conceptual model

developed by the students, the final report submitted to NPS will evaluate how climate-induced changes in physical habitat are likely to be reflected in foodweb changes in the Upper Kobuk River and Walker Lake All survey data will be made available through the course website In addition, we will work closely with NPS biologists to coordinate

sampling locations and protocols to support on-going park research

IIa Overview: Ecogeomorphology course

The University of California, Davis Departments of Geology and Wildlife, Fish and

Conservation Biology annually sponsor a field course in Ecogeomorphology The goal of the course is to bring together students from diverse backgrounds in hydrology, geology, aquatic ecology and fish biology, and to involve them in interdisciplinary study of riverine ecosystems This is one of the few courses that provide direct training in working with specialists from other disciplines—something that all of our students have to do when they leave our university

The course is structured around an issue in watershed and riverine management The students spend ten weeks in class studying this issue, collaborating on the preparation of reports, and publishing their work on the web At the end of the course, the students visit a selected watershed that is impacted by the issue examined during the course This visit, unlike most field trips, involves data collection and analysis by designated

multidisciplinary field teams The data collected can range from simple, empirical

observations about riparian and aquatic ecology to more rigorous, systematic field surveys, including geomorphic surveys and habitat maps At the end of the field work, the students are required to prepare a synthesis document that places their observations within the context of the management issue that is studied

In previous years (and under a different name), the course has examined the importance of dynamic habitats in glacially-influenced rivers (Copper River, Alaska study), the influence

of land use practices on salmonid rearing habitat (Scott River, California study), the

importance of tributary-mainstem interaction on habitat heterogeneity and associated biodiversity (Skeena River, British Columbia study), river restoration through pulse flows (Colorado River study), and impacts of dams on native fish habitat (Green River/Dinosaur National Monument study) The web-published results of these studies and a more

complete description of the course can be seen at:

http://www.geology.ucdavis.edu/~shlemoncourse/

IIb Overview: proposal background

This year’s Ecogeomorphology course is focusing on the effects of climate change on an Arctic river, through development and testing of a conceptual model The premise is that there are predictable changes in river systems in response to climate change, based on expected changes in amount and timing of flow and changes in nutrient dynamics The Kobuk River, as a relatively undisturbed Arctic system, offers an ideal venue for empirical field studies to examine and predict climate change effects The course instructors/leaders

have broad experience in studying river processes and their effects on fish and other biota,

as shown in Mount (1995) and Moyle (2002) and attached resumes

A Statement of issue

Climate change is having a more powerful influence on Arctic ecosystems than on any other ecosystems in the world Arctic river systems and their biota are going to be

increasingly affected by major changes in the flow regime, especially timing of peak flows, increase in flows, extent of high flows, changes in water quality and nutrient dynamics, and changes in riparian and aquatic community structure and composition Arctic rivers, with their likely strong response to warming, are a good place to start to develop predictive models of climate change impacts These relatively undisturbed rivers are also ideal for training students to design research programs and to develop conceptual models that can be used to predict biotic and physical system responses to climate change

B Literature summary

An important function of ecogeomorphology course is to have the students develop a comprehensive background literature survey Students will assemble an exhaustive

bibliography of relevant papers, including published and unpublished, or “grey” literature This survey, which will be made available to the NPS upon completion and will be posted

on the course website; it will also form the basis of the conceptual model developed this spring The literature summary below is therefore only meant to show major issues and sources of information, rather than being exhaustive

The literature on Arctic freshwater systems and how they will be affected by

climate change is summarized in a series of excellent symposium papers in Ambios (see introduction by Wrona et al 2006) and in the Journal of Geophysical Research (see

Vorosmarty et al 2008) A basic conclusion from the Ambios symposium is that climate

change effects are hard to predict because of the “poor understanding of Arctic freshwater systems and their basic interrelationships with climate and other environmental variables, and partly due to a paucity of long-term freshwater monitoring sites and integrated

hydrological research programs in the Arctic (Wrona et al.2006, p 326)” Likewise,

Vorosmarty et al.(2008) conclude: “Our understanding of the drivers and responses to change, while substantially improved by the last decade of Arctic water cycle research, still requires much work (p.5).” Concern over Arctic rivers has increased greatly in recent years with the realization that (1) climate change is already having dramatic effects on Arctic ecosystems (Smol and Douglas 2007) and (2) Arctic flow regimes are likely to be the most altered in the world, with flows greatly increased by melting permafrost and other changes (Palmer et al 2008)

The Kobuk River watershed is one of the largest in northwest Alaska (31, 028

km2) and the river has an annual average flow of 438 m3 sec (Brabetts 2001) The Upper Kobuk River, including the portions within the Gates of the Arctic National Park and Preserve, is also one of the most pristine in Alaska, if not the world, forming an ideal site to distinguish the effects of climate change from other anthropogenic influences Most rivers show a high degree of disturbance so observing one with minimal change from human use

is an unusual opportunity (Poff et al 1997; Poole 2002; Postel and Richter 2003) Within the Park the river has a broad array of habitats typical of Arctic rivers, ranging from deep headwater lakes to steep-gradient bedrock rivers to highly sinuous, meandering alluvial

rivers with broad permafrost floodplains The lack of significant glaciers within the watershed increases ease of study, because clearer water may make underwater observation possible

Flows in the Kobuk River are high in summer and low in winter The summer river is apparently also comparatively warm (14-16°C) and productive, so is an attractive rearing area for fish, which move downstream from headwater lakes, upstream from the ocean, or laterally from floodplain lakes The fish fauna contains about 16 documented species (out of 22 possible), although only about 13 are encountered on a regular basis (Table 1) Most of the species but especially the coregonids, have been little studied in Arctic rivers although some basic biological information is available (Morrow 1980, Mecklenburg et al 2002, and references therein) Many of the species are also found in Arctic Siberia

Chum salmon Oncorhynchus keta Pink, coho, and Chinook

and sockeye also present

on occasion Arctic char/Dolly

varden

Salvelinus alpinus/ S

malma

Both species may be part

of a char complex

Arctic grayling Thymallus arcticus

Inconnu (sheefish) Stenodus leucichthys

Least cisco Coregonus sardinella

Broad whitefish Coregonus nasus

Humpback whitefish Coregonus

clupeaformis

Round whitefish Prosopium

cylindraceum

Northern pike Esox lucius

Long-nosed sucker Catostomus

catostomus

Slimy sculpin Cottus cognatus

Alaska blackfish Dallia pectoralis

Nine-spine

stickleback

Pungitius pungitius

Table 1 Common fishes of the Kobuk River Over 22 species could potentially occur in the river, so this represents a minimal list for the upper watershed (Mecklenburg et al 2002; C Zimmerman, USGS, Anchorage, pers comm.) Pond smelt (Hypomesus

olidus) rainbow smelt (Osmerus mordax), pink Salmon (Oncorhynchus gorbuscha), and Bering cisco all occur in the lower watershed but are

unlikely to be found at sampling sites above Kobuk Village King

salmon (O tshawytscha) as well as other Pacific salmon are present

annually but in extremely low numbers Individuals appear to be

strays (Jim Menard, ADFG, Kotzebue, pers comm.)

The conceptual models will be developed using a format a number of us are familiar with, developed for California’s Sacramento-San Joaquin Delta An example of a model for a Kobuk foodweb is presented in Figure 1, which was developed by John Durand, one of the graduate students enrolled in the course The model is very preliminary but provides some idea of what we plan to develop

Figure 1 Preliminary conceptual model of Kobuk River foodweb, to demonstrate the kind of model we will produce Each box will contain a submodel of

interactions Explanations of the arrows follow the circled numbers, as

indicatedbelow

Explanations for drivers (arrows) in food web model for Kobuk River This is a very preliminary model, for demonstration, based on more detailed models developed for the Sacramento-San Joaquin Delta Information on the Kobuk River is from Brabetts (2001), inferred from studies of other arctic systems (Wrona et al 2006; Vorosmarty et al 2008), and from the principal investigator’s knowledge of river ecosystems

1.11 Turbidity to Primary Production

Changes in water clarity can impact the rate of primary production in aquatic plants, or emergence in shallow water vegetation Under conditions of stratification, high turbidity may inhibit periphyton production Warming trends may increase the amount of carbon inputs through changes in decomposition, runoff and cycling rates, affecting turbidity 1.12 Residence Time to Nutrients etc

Residence time of water in backwaters, floodplain ponds, pools, and other geomorphic features affects ability of plants to utilize nutrients and carbon, as well as the population abundance of benthic organisms

1.13 Temperature to Organic Carbon/Nutrients

Temperature may affect rate at which organic carbon and nutrients are cycled through the ecosystem Increased temperatures may result in release of carbon and nutrients that have been locked in storage due to freezing or terrestrial sequestration

1.21 Nutrients to Primary Production

Nutrient availability may be a key controlling factor on primary production rates

1.31 Primary Production to Benthic Invertebrates

Aquatic insects are largely responsible for converting periphyton, leaf litter, and riparian vegetation to available biomass for higher trophic organisms

1.32 Benthic production to Drift

Drifting aquatic and terrestrial invertebrates are a major source of energy transfer (food) converting periphyton and terrestrial organic matter (e.g., leaves) to available biomass for higher trophic level organisms

1.41 Organic Carbon to Microbial Organisms

Organic carbon may be utilized by a variety of unicellular organisms from bacteria to ciliates This alternate foodweb is driven not be primary production but by sediment release or organic cycling Organic carbon based foodwebs tend to be many-tiered, more reticulate and less productive for higher trophic level organisms

1.51 Microbial Organisms to Benthic Invertebrates

Aquatic insects may use microbial organisms; usage may increase with increased

sediment inputs Organismal shifts may occur if primary production is suppressed and organic carbon is increased by large influxes of sediments

1.61 Benthic Invertebrates to Fish

Aquatic insects form and important component of diet for many stream fishes

1.62 Benthic Invertebrates to Mammals

Aquatic insects form and important component of diet for many mammals

1.63 Benthic Invertebrates to Fish

Aquatic insects form and important component of diet for many birds

1.71 Drift to Fish

Many fish species rely on drift as a major source of food

1.81 Fish to Mammals

Fish may form a critical part of the diets of large mammals, particularly bears

1.82 Fish to Birds

Fish may form a critical part of the diets of birds

1.91 Consumers to Nutrients

Waste from consumers is directed back into the nutrient cycle via direct aquatic inputs, or from terrestrial inputs which are transported to the aquatic environment through runoff Nutrient pools are subject to changes in temperature which may affect metabolic rates (both for uptake and release), and to changes in both terrestrial and aquatic residence time (influenced largely by runoff) Atmospheric may have a large impact as well, especially

in low nitrogen ecosystems In addition, spawning chum salmon may be a major source

of nutrients for the system

C Scope of Study

The field portion of the study will take place August 11-23 from the mouth of Walker Lake

to the town of Kobuk (Figure 2) Approximately two thirds of the sampling will be within the Gates of the Arctic National Park and Preserve The remainder of the sampling will be west of the Park above Kobuk

In order to maximize observable downstream changes in habitats and foodwebs, we will traverse the river by raft We intend to spend at least one and one-half days sampling the lake to gain a better understanding of a major source of water, nutrients, and fish Upon leaving Walker Lake, we will focus our sampling efforts within the three river segments shown in Figure 2 Using a stratified sampling approach, we will stop at approximately 10 locations on the mainstem to sample fish, invertebrates, and water quality, plus an

additional 10 sites on tributaries to sample invertebrates and water quality The locations will be divided among the three major geomorphic reaches of the Kobuk: the canyon reach, upper Nazuruk reach, and lower Nazuruk reach (Figure 2) Sampling site locations will be vetted with Park biologists in order to maximize their contribution to on-going Park

studies At each of these locations we will: 1) prepare a geomorphic/habitat map using standard surveying techniques; 2) characterize water quality and flow conditions within each habitat; and 3) sample invertebrates and, where possible, fish All study sites will be geospatially located using GPS (Trimble XM) Information collected at each site will be documented in field notes and data sheets and incorporated into a class GIS During the entire traverse from Walker Lake to Kobuk we will use a Hydrolab to continuously record water temperature, turbidity, clarity, conductivity, and pH

Figure 2 Map of study reaches of Kobuk River.

D Intended use of results

This study is primarily for the purpose of training beginning graduate students to work in interdisciplinary teams to determine the potential effects of climate change The results, however, will be posted on a website, so will be available as background material for others

to use, and will contribute to the basic background on the ecology of the Kobuk River Because our sites will be geospatially located (i.e., our data will be posted and linked to each site on a GIS-based map), the information could form the basis for repeated samplings

in the future Our intention is also to publish a formal, peer-reviewed paper on the

conceptual model of climate change effects in an Arctic River

III Objectives

Our objective is to make inferences about the impact of climate change on an Arctic River ecosystem, using conceptual models as the framework for analysis As part of the

refinement of this model, our field studies will document faunal diversity and composition changes due to: distance and declining influence from Walker Lake, downstream increase

in tributary influence with distance from the lake, downstream changes in habitat with overall decline in gradient, and localized habitat heterogeneity associated with

tributary/mainstem interactions The focus of the conceptual model development will be

on food web dynamics (and the physical influences on food webs) in order to make first-order predictions about the impact of climate change

IV Methods

A Study Area

The area of study is shown in Figure 2 We have broken our study up into one lake study site (mouth of Walker Lake) and 20 sites within three river segments, based on general geomorphic and hydrologic conditions Within each of the three river segments, we

propose to conduct surveys at six to seven sites, divided equally between mainstem sites that exhibit representative habitat conditions and tributary confluences The precise

locations of proposed sampling locations will depend on access (landing) points along the river and distance from previous area

B Procedures

An important element of this class is to practice low-impact camping and research The Ecogeomorphology course has a long tradition in this regard, including experience working

in remote settings (e.g Copper River, Skeena River) as well as in National Parks

(e.g.,Wrangell-St Elias, Grand Canyon, Dinosaur National Monument) We recognize that

we are a large group (14 total) and that special care must be taken to minimize our impacts

on the land, wildlife and other park visitors To that end, our research practice will be to move camp every day, select gravel bar or bare point bar sites where possible for camping, confine our activity to the river and riparian corridor, and to leave no trace Additionally, all of our field protocols involve non-destructive sampling methods that minimize impact

on the habitats and wildlife we are studying Our trip leader is Dennis Johnson, an expert

on Leave No Trace camping with experience on many remote rivers, including leading our trips down the Copper River and Skeena River (B.C.) Mr Johnson is the Director

Emeritus of UC Davis Outdoor Adventures, where Leave No Trace camping principals are

an integral part of the student training curriculum We will seek additional input from NPS

on the unique challenges of the Kobuk environment before we start the trip

At each river survey site, the following procedures will be followed All of the information collected will be used to constrain or inform a conceptual model like the one shown in Figure 1

 Development of a geomorphic/habitat map This georeferenced map will be used to locate all invertebrate and fish sampling sites and to characterize physical habitat conditions The map will be constructed using a combination laser rangefinder and tape Where feasible, topographic and channel cross sections will be surveyed using standard techniques Where riparian plants are to be surveyed, we will establish 50-100m transects using standard survey techniques All transects and sampling points will be located using GPS No permanent benchmarks or

monuments will be established and no site excavations will occur

 Small fish will be collected using a 10 x 1.2m beach seine, with a 1x1x1 m bag, and

5 mm mesh and a 3.2 x 1.2m seine with 3 mm mesh All fish collected will be removed from the net immediately and placed alive in buckets of water Fish in the buckets will be identified, measured (fork length) and returned to the water If more than 25 individuals of any species are collected, only the first 25 will be measured if fish appear to be stressed At each site a minimum of two seine hauls will be made with the 10 m bag seine and the area covered by each haul determined Basic sampling and recording procedures follow Overton et al (1997) and Moyle et al

(2003) Species will be identified using keys and information in Mecklenberg et al (2002) and Morrow (1980) Where identification is questionable, photographs will

be taken for possible later confirmation of tentative identification

 Large predatory fish will be sampled using hook-and-line, following legal sport-fishing regulations, identified, and measured Efforts will be made to geolocate all catches

 Samples of both large and small fish will have stomach contents determined using a simple gastric lavage, consisting of a squirt bottle and small aquarium net into which the gut contents are flushed with one or two quick squirts of water We have found this procedure works well for field determination of diets because it is rapid and does little harm to the fish

 Where feasible, aquatic invertebrates will be sampled using kick nets in riffles or by sweeping shallow areas with a dip net All invertebrate samples will be sorted and identified to family in the field; EPT indices, species richness, and other measures will be determined from the data, using rapid bioassessment procedures (Harrington and Borne 2000) For kick net samples, a minimum of three will be taken at each site Invertebrates will be kept alive during sorting (in pans and ice cube trays) and returned to the water after counting

 All sampling sites will be characterized based on their water quality conditions At each fish or invertebrate sampling location, depth, substrate (using Wolman counts

in coarse sediment sites) and water quality (secchi depth, conductivity, pH,

temperature and dissolved oxygen) will be measured This information will be integrated with the longitudinal water quality survey to be measured using the Hydrolab In addition, at selected sites we will conduct more detailed water quality assessments in order to evaluate the influence that nutrient dynamics may play in driving primary productivity

 Grab samples of water will be taken in triplicate and analyzed using a hand held colorimeter We will measure concentrations of the following water quality

constituents in Walker Lake and the Kobuk River

Reactive Phosphorus HACH Phosver 3

Tests for P, N, Si, Fe and Mn will give an indication of micronutrient concentrations and existing nutrient limitations in the system Tests for B, Cu, Si,

Ca and Fe will give some clues as to the existing populations of plankton species and the potential for invasion by other plankton species in the system

 All birds and mammals observed in the sample site region will be identified and rough abundance scored (1 = just one sighting; 3 = common, seen on most days,