Minnesota Sea Grant

Abstract Global concern about human impact on biological diversity has triggered an intense research agenda on drivers and consequences of biodiversity change in parallel with international policy seeking to conserve biodiversity and associated ecosystem functions. Quantifying the trends in biodiversity is far from trivial, however, as recently documented by meta‐analyses, which report little if any net change in local species richness through time. Here, we summarise several limitations of species richness as a metric of biodiversity change and show that the expectation of directional species richness trends under changing conditions is invalid. Instead, we illustrate how a set of species turnover indices provide more information content regarding temporal trends in biodiversity, as they reflect how dominance and identity shift in communities over time. We apply these metrics to three monitoring datasets representing different ecosystem types. In all datasets, nearly complete species turnover occurred, but this was disconnected from any species richness trends. Instead, turnover was strongly influenced by changes in species presence (identities) and dominance (abundances). We further show that these metrics can detect phases of strong compositional shifts in monitoring data and thus identify a different aspect of biodiversity change decoupled from species richness. Synthesis and applications : Temporal trends in species richness are insufficient to capture key changes in biodiversity in changing environments. In fact, reductions in environmental quality can lead to transient increases in species richness if immigration or extinction has different temporal dynamics. Thus, biodiversity monitoring programmes need to go beyond analyses of trends in richness in favour of more meaningful assessments of biodiversity change.

Abstract Lakes and impoundments are an important source of methane (CH 4 ), a potent greenhouse gas, to the atmosphere. A recent analysis shows aquatic productivity (i.e., eutrophication) is an important driver of CH 4 emissions from lentic waters. Considering that aquatic productivity will increase over the next century due to climate change and a growing human population, a concomitant increase in aquatic CH 4 emissions may occur. We simulate the eutrophication of lentic waters under scenarios of future nutrient loading to inland waters and show that enhanced eutrophication of lakes and impoundments will substantially increase CH 4 emissions from these systems (+30–90%) over the next century. This increased CH 4 emission has an atmospheric impact of 1.7–2.6 Pg C-CO 2 -eq y −1 , which is equivalent to 18–33% of annual CO 2 emissions from burning fossil fuels. Thus, it is not only important to limit eutrophication to preserve fragile water supplies, but also to avoid acceleration of climate change.

Abstract Lakes and impoundments are important sources of greenhouse gases (GHG: i.e., CO 2 , CH 4 , N 2 O), yet global emission estimates are based on regionally biased averages and elementary upscaling. We assembled the largest global dataset to date on emission rates of all three GHGs and found they covary with lake size and trophic state. Fitted models were upscaled to estimate global emission using global lake size inventories and a remotely sensed global lake productivity distribution. Traditional upscaling approaches overestimated CO 2 and N 2 O emission but underestimated CH 4 by half. Our upscaled size‐productivity weighted estimates (1.25–2.30 Pg of CO 2 ‐equivalents annually) are nearly 20% of global CO 2 fossil fuel emission with ∼ 75% of the climate impact due to CH 4 . Moderate global increases in eutrophication could translate to 5–40% increases in the GHG effects in the atmosphere, adding the equivalent effect of another 13% of fossil fuel combustion or an effect equal to GHG emissions from current land use change.

We present the results of mapping selected cross-sections across the margins of the Chinese Tien Shan, an intracontinental mountain belt that formed in response to the India-Eurasia collision. This belt contains significant lateral variation in topography, structure, and stratigraphy at all scales, and our estimated rates of shortening also reveal a distribution of shortening that varies laterally. At the largest scale, it consists of two major high mountain ranges in the west that merge eastward into a complex, single high mountain belt with several distinct ranges, then separates farther eastward into several low mountain ranges in the south and a single narrow high mountain range in the north. Active fold-and-thrust belts along parts of the north and south flanks of the Tien Shan involve only Mesozoic and Cenozoic sedimentary cover, which varies in both stratigraphy and structure from east to west. The southern fold-and-thrust belt decreases in width and complexity from west to east and ends before reaching Korla. The northern belt begins near the longitude where the southern belt ends, and increases in width and complexity from west to east. Within these two fold-and-thrust belts are both E-W and N-S variations in stratigraphy at the scale of the fold-and-thrust belts and across individual structures. All these variations make it very difficult to generalize either structure or stratigraphy within the Tien Shan or within local areas. Four maps and cross-sections, two across each of the northern and southern fold-and-thrust belts, imply different magnitudes of shortening. In the eastern part of the northern belt, a cross-section along the southern part of the Hutubi River yields shortening of 6.2 km, and a section to the north across the Tugulu anticline yields shortening of 5.5 km. The two parts of the cross-section cannot be added because the Tugulu anticline lies 20 km west of the Hutubi River, and diminishes greatly in amplitude toward the Hutubi River. In the western part of the northern belt, cross-sections require 4.6 to 5.0 km of shortening at Tuositai and 2.12 to 2.35 km across the Dushanzi anticline. The Tuositai structure lies south of the Dushanzi anticline, but shortening in these two areas also cannot be summed, because they seem to be separated by a N-trending strike-slip fault. In the western part of the southern fold-and-thrust belt, an incomplete cross-section along the Kalasu River suggests shortening of 12.1 to 14.1 km. If the estimated shortening of 6 to 7 km in the Qiulitage anticline, which we did not map, is added, the total shortening in this cross-section would be ∼18 to 21 km. To the east, a complete cross-section at Boston Tokar yielded shortening of 10.3 to 13.0 km. Calculating long-term shortening rates from these four cross-sections is difficult, because the time of initiation of deformation is poorly known. In the Kalasu River area of the southern belt, there is evidence that limited shortening of 2 to 4 km occurred in the early Miocene, if major thickness changes in deposition of conglomerate unit 3b are interpreted to be growth strata. Geological evidence suggests that most of the shortening began in both belts after the beginning of the deposition of the thick conglomerate unit shown as lower Quaternary on Chinese geological maps. Strata within the middle part of these conglomerates were deposited during the growth of the folds. Presence of Equus near the base of similar conglomerates indicates a Quaternary age, but the fossil localities are far from most of our cross-sections, and the contemporaneity of the rocks remains in question. The beginning of conglomerate deposition may be controlled by climate change, and if so, the beginning of conglomerate deposition may be generally contemporaneous throughout the region at ∼2.5 Ma. Deformation began at some time after the onset of conglomerate deposition, but this time is not well constrained. Thus we have calculated shortening rates for 2.5, 1.6, and 1.0 Ma that should bracket maximum and minimum slip rates. These calculations yield the following ranges in the northern fold-and-thrust belt: southern Hutubi River = 2.5 to 6.2 mm/yr; Tugulu anticline = 2.1 to 5.5 mm/yr; Tuositai anticline = 1.8–2.0 to 4.6–5.0 mm/yr; and Dushanzi anticline = 0.8 to 2.1–2.4 mm/yr; and in the southern fold-and-thrust belt: Kalasu River = 4.6–5.6 (including the Qiulitage anticline = 7.2–8.4) to 12.1–14.1 (including Qiulitage anticline = 18–21) mm/yr; and at Boston Tokar = 4.1–5.2 to 10.3–13.1 mm/yr. If 2 to 4 km of shortening occurred in the Kalasu River section during early Miocene time, the long-term rates for Quaternary time are 3.2–4.8 (including Qiulitage anticline = 5.6–7.6) to 8.1–12.1 (including Qiulitage anticline = 14–19) mm/yr. Calculation of the shortening rate across the entire width of the Tien Shan is difficult because of the rapid lateral variations in structure and because of active deformation within the range, which we have not studied. The cross-sections at Boston Tokar in the south and Tuositai in the north lie along the same longitude. Adding the shortening rates in these areas would yield a minimum range (using 2.5 Ma as the initiation time) of 5.7 to 7.2 mm/yr. If deformation began at 1.6 or 1.0 Ma, the range of shortening rates would be 10–11.2 mm/yr to 14.9–18.1 mm/yr, respectively. Because the first indication of structural growth with the mapped areas occurs above the base of the conglomerates at the top of the stratigraphic succession, a minimum shortening rate greater than 5.7 to 7.2 mm/yr is more likely. Both the marginal fold-and-thrust belts have a thin-skinned geometry with the drcollement at -6 to 10 km and within Mesozoic and Cenozoic sedimentary rocks. Toward the interior of the range the decollement must pass into the Paleozoic basement rocks and steepen beneath the flanks of the range. The structural style is similar to that in the Laramide Rocky Mountains and the California Transverse Ranges. The highest parts of the Tien Shan are adjacent to areas of active shortening. Such a relation might suggest that the major uplift of the Tien Shan is very young, mostly latest Cenozoic or Quaternary in age. The shortening across the Tien Shan is inhomogeneous and spatially distributed.

Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.

Food‐web components of a Lake Superior coastal wetland and adjacent offshore waters were examined with stable isotope ratiotechniques for carbon and nitrogen. We found distinct carbon isotope ratio signatures for organisms collected in the wetland and from offshore. Both food‐web groups seemed to be based on carbon fixed by phytoplankton. Compared to offshore organisms, the wetland food web was depleted in 13 C. We found the nitrogen isotope ratio signatures to be enriched in 15 N by ~3‰ at each succeeding trophic level in both wetland and lake samples. No evidence of a direct energy link between the abundant macrophyte biomass in the wetland and the fisheries food web was found. The carbon ratio of rainbow smelt ( Osmerus mordax ) and walleye ( Stizostedion vitreum ) exhibited a shift from a wetland signature in young‐of‐the‐year to an offshore signature in juveniles and adults. Yellow perch ( Perca flavescens ) young‐of‐the‐year exhibited a planktivorous δ 15 N signature, while adults were enriched in 15 N. Both examples illustrate the utility of stable isotope ratio techniques in confirming feeding shifts associated with growth and habitat change.

Nitrogen (N) and phosphorus (P) commonly co-limit primary productivity in lakes, and chlorophyll a (Chl-a) is predicted to be greatest under high N, high P regimes. Because land use practices can alter N and P biogeochemical cycles in watersheds, it is unclear whether previously documented phytoplankton–nutrient relationships apply where landscapes are highly disturbed. Here, we analyzed a lake water quality database from an agricultural region to explore relationships among Chl-a, total N (TN), and total P (TP) under extreme nutrient concentrations. Chl-a was weakly related to TN when TP was ≤100 μg L−1 but displayed a stronger response to TN at higher TP. When TP exceeded 100 μg L−1, Chl-a increased with increasing TN until reaching a TN threshold of ~3 mg L−1 and decreased thereafter, resulting in a high nutrient, low Chl-a region that did not coincide with shifts in nutrient limitation, light availability, cellular Chl-a content, phytoplankton composition, or zooplankton grazing pressure. Beyond the threshold, nitrate comprised most of TN and occurred with reduced dissolved organic matter (DOM). These observations suggest that photolysis of nitrate may produce reactive oxygen species that damage DOM and phytoplankton. Reduction in N loading at high P could therefore increase Chl-a and decrease water clarity, resulting in an apparent worsening of water quality. Our data suggest that monitoring Chl-a or Secchi depth may fail to indicate water quality degradation by extreme nutrient concentrations. These findings highlight how extreme nutrient regimes in lakes can produce novel relationships between phytoplankton and nutrients.

People with mental retardation, autism, and related developmental disabilities who self-injure are treated with a wide array of behavioral techniques and psychotropic medications. Despite numerous reports documenting short-term and some long-term changes in self-injury associated with the opiate antagonist naltrexone hydrochloride, no quantitative review of its efficacy has been reported. We conducted a quantitative synthesis of the peer-reviewed published literature from 1983 to 2003 documenting the use of naltrexone for the treatment of self-injurious behavior (SIB). Individual-level results were analyzed given subject and study characteristics. A sample of 27 research articles involving 86 subjects with self-injury was reviewed. Eighty percent of subjects were reported to improve relative to baseline (i.e., SIB reduced) during naltrexone administration and 47% of subjects SIB was reduced by 50% or greater. In studies reporting dose levels in milligrams, males were more likely than females to respond. No significant relations were found between treatment outcomes and autism status or form of self-injury. Results are discussed with respect to future efficacy work related to study outcomes and the pharmacological treatment of self-injury.

The dichotomy of conservation vs. sustainable development has generated numerous debates since the introduction of the latter in the late 1980s. In the recent past, many initiatives to address the issue gained ground worldwide, such as ecotourism, a form of tourism that takes place in natural areas, sustains local communities, and involves a learning experience. Even though it might look like the perfect tool to strengthen the link between conservation and sustainable development, ecotourism faces many challenges. Through a case study of Monviso Transboundary Biosphere Reserve, this research aims at understanding local stakeholders’ perspectives on the matter. A series of interviews were conducted to explore the possibility for ecotourism to act as a learning tool. Results show that ecotourism had some positive effects, such as the creation of a network for collaboration between various stakeholders. However, negative perceptions still play an inhibiting role. It is discussed that this might be a consequence of one main factor: a lack of proper environmental education. Adjustments in the language and methods used in the educational system and a change of course at higher governmental levels might support ecotourism as a learning tool and a catalyst for sustainable development.

This study explored the possibility that environmental estrogens in sewage effluent may reduce the reproductive fitness of adult male fish by suppressing their reproductive behaviors, including their ability to compete for nests and females. Male fathead minnows (Pimephales promelas) were exposed for three weeks to either blank control, effluent released by a sewage treatment plant (STPE), waterborne estradiol (E2), or a synthetic androgen (methyltestosterone [MT]). Afterward, fish were placed with females and a nest, and their behavior was monitored for 5 d in either the presence or the absence of a competing (unexposed control) male. Males exposed to either the STPE or E2 (approximately 50 ng/L, a level chosen to mimic the estrogenic content of the STPE) had elevated levels of circulating vitellogenin (p < 0.05) and lower levels of 11-ketotestosterone (KT; p < 0.05). Nearly all STPE- and E2-exposed males spawned successfully in the absence of a competing male, but in both cases, exposed males suffered nearly total reproductive failure when they had to compete. Conversely, males exposed to MT (approximately 50 ng/L) outcompeted control males. Behavioral observations suggested that subtle differences in agonistic behaviors, typically associated with circulating androgens (i.e., KT), were responsible. We speculate that male fish exposed to estrogenic effluent in the field are less likely to reproduce successfully within large populations of wild fish, thereby causing abnormal and potentially detrimental patterns of gene flow within those populations.

Surface water is among Earth's most important resources. Yet, benefit-cost studies often report that the costs of water quality protection exceed its benefits. One possible reason for this seeming paradox is that often only a narrow range of local water quality benefits are considered. In particular, the climate damages from water pollution have rarely been quantified. Recent advances in global water science allow the computation of the global methane emission from lakes caused by human nutrient enrichment (eutrophication). Here, we estimate the present value of the global social cost of eutrophication-driven methane emissions from lakes between 2015 and 2050 to be $7.5-$81 trillion (2015 $US), and in a case-study for one well-studied lake (Lake Erie) we find the global value of avoiding eutrophication exceeds local values of either beach use or sport fishing by 10-fold.

Abstract Large woody debris (wood) plays a number of important roles in forested stream ecosystems. Wood in streams provides habitat and flow refugia for fish and invertebrates, and is a site of biofilm production that serves as food for grazing organisms. Logs added to streams are rapidly colonized by invertebrates, and this habitat alteration is accompanied by changes in community composition and functional processes. A multiple habitat, qualitative sampling approach was employed to evaluate macroinvertebrate communities associated with wood habitats in 71 stream reaches in central Michigan and southeastern Minnesota, two agricultural regions in the midwestern United States. Macroinvertebrate taxa were classified with respect to behaviour (e.g. sprawler, clinger, swimmer), as well as trophic/feeding characteristics. These traits were used to examine community structure as a function of wood abundance and distribution. Although wood is not abundant in these streams and logs are generally small in size, wood is a very important habitat in both Michigan and Minnesota: 86% and 95% of the total taxa encountered at Michigan and Minnesota study sites, respectively, were found in wood habitats. Differences in regional patterns in the distribution of taxa across habitats were observed between Michigan and Minnesota. These are believed to result from differences in the number of habitat types available, and the dominant substrate composition. Local invertebrate diversity increased in Michigan, but not Minnesota, with the presence of wood habitats in streams. The presence of wood at a site increased the average taxa richness by 15 and 10 taxa in Michigan and Minnesota, respectively. Macroinvertebrate behavioural attributes and functional traits associated with wood habitats suggest that community traits may vary due to both local difference in flow and the location of wood in the channel. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Stable‐isotope ratio signatures of primary producers in a coastal wetland and in adjacent offshore waters of western Lake Superior indicated that phytoplankton are the primary source of carbon for the grazing food web of this ecosystem. This study outlines the possible roles of other autotrophs in this regard. Isotopic signatures of macrophytes reflected their life‐form‐associated constraints on diffusion of inorganic carbon. Data indicated that differences between wetland and lake phytoplankton may be explained by the isotopic signatures of their dissolved inorganic carbon (DIC) sources. Results of an in situ experiment showed that respiration associated with macrophyte decomposition is capable of enriching surrounding water with significant amounts of 13 C‐depleted DIC and lowering the net δ 13 C ratio of DIC in water in lowturbulence situations. The δ 13 C ratio for wetland phytoplankton may be depleted relative to pelagic algae because the fixed carbon is derived from decomposing detritus.

Abstract The bactericidal activity of monocyte-rich cell suspensions obtained from the peripheral blood of patients with fatal granulomatous disease (FGD), their mothers and normal controls was studied. Defective killing of Staphylococcus aureus, Strain 502A, by monocyte-rich cell suspensions from children with FGD was found when compared with monocyte-rich suspensions from normal controls. This defect, less severe, was also observed in the mothers of affected patients. In this selected population of mothers, the monocyte defect varied in parallel with the previously described neutrophil defect.

Abstract While the disciplines of oceanography and limnology often operate in isolate, freshwater, estuarine, and marine ecosystems are intricately linked. The emphasis of this special issue for Limnology and Oceanography is on the aquatic continuum and the connectivity between aquatic ecosystems from headwater streams and inland waters, to coastal and marine systems. Changes in the transport and transformation of elements as well as ecological functions occur along this aquatic continuum. Assemblages of organisms change in a way that reflects the ecological and biogeochemical conditions of the aquatic gradient. Here, we highlight research progress in limnology and oceanography across the aquatic continuum and at the interfaces of headwaters to oceans. Contributions explored nutrient and carbon dynamics which included release, transportation, transformation, and stoichiometry from freshwaters to marine. The special issue also explored food web continua, including functional changes, biodiversity gradients, and photosynthesis and respiration comparisons among ecosystems at different points in the continuum. Rapid improvements in biomolecular techniques, use of long‐term datasets, applications of novel statistical methods, and improved upscaling methods can transform the way aquatic scientists are describing biological organisms and communities from freshwaters to oceans. One important conclusion is the recognition that anthropogenic activities such as invasive species and nutrient pollution trigger challenge the current concepts of aquatic continua including the river continuum concept, the land to ocean continuum, river to estuary systems, and the submarine groundwater discharge. Both limnologists and oceanographers have much to gain from exchanging information with one another, especially in light of global change.

The Gulf of Mexico red snapper fishery has been declared as overfished, and overfishing is occurring. More stringent regulations, including reduced catch quotas and restrictions on the shrimp fishery to reduce bycatch of juvenile snappers, are anticipated. However, with projected rebuilding, maximum sustainable yield (MSY) is estimated to be between 11 and 25 million pounds. This exceeds previously recorded annual yields from U.S. Gulf waters. The fishery began during the mid 19th century off the northeastern Gulf coast, with harvests of only about 2 million pounds. Even at this rate, the stocks were depleted rapidly, and the fleets moved further south and east to find new sources. Numerous exploratory cruises to the western Gulf in the late 19th century found minimal snapper populations, but high concentrations discovered off Vera Cruz, Mexico, attracted fishers, and this area was the major source of snappers for more than a century. The deployment of petroleum structures in the mid 20th century in the western Gulf and thousands of artificial reefs in the north-central Gulf have markedly increased red snapper habitat in those areas. Currently, snapper populations around artificial reefs in the north-central and northwestern Gulf support the majority of the U.S. harvest. If habitat is limiting, the designations of “overfishing” and “overfished” may be misleading, and “unrealized harvest potential” may be a more accurate descriptor of the current status of the stock given the increased presence of additional habitat for red snapper. Decreases in these artificial structures (owing to natural degradation or removal) may decrease future harvest potential.

Abstract Residual currents induced by asymmetric tidal mixing were examined for weakly stratified, narrow estuaries using analytical and numerical models. The analytical model is an extension of the work of R. K. McCarthy, with the addition of tidal variations of the vertical eddy viscosity in the longitudinal momentum equation. The longitudinal distribution of residual flows driven by asymmetric tidal mixing is determined by the tidal current amplitude and by asymmetries in tidal mixing between flood and ebb. In a long channel, the magnitude of the residual flow induced by asymmetric tidal mixing is maximum at the estuary mouth and decreases upstream following the longitudinal distribution of tidal current amplitude. Larger asymmetry in tidal mixing between flood and ebb produces stronger residual currents. For typical tidal asymmetry, mixing is stronger during flood than during ebb and results in two-layer residual currents with seaward flow near the surface and landward flow near the bottom. For reverse tidal asymmetry, mixing is weaker during flood than during ebb and the resulting residual flow is landward near the surface and seaward near the bottom. Also, the residual flow induced by tidal asymmetry has the same order of magnitude as the density-driven flow and therefore is important to estuarine dynamics. Numerical experiments with a primitive-equation numerical model [the Regional Ocean Modeling System (ROMS)] generally support the pattern of residual currents driven by tidal asymmetry suggested by the analytical model.

BACKGROUND: Dyslipidaemia is very common in patients with HIV infection, but current therapies are often suboptimal. Since niacin may cause insulin resistance and hepatotoxicity, it has generally been avoided in this setting. METHODS: Non-diabetic male subjects (n=33) who had well-controlled HIV infection on antiretroviral therapy, fasting triglycerides > or =2.26 mmol/l and non-high density lipoprotein cholesterol (non-HDL-C) > or =4.66 mmol/l received escalating doses of extended-release niacin (ERN) up to 2,000 mg nightly for up to 44 weeks. RESULTS: Fourteen subjects (42%) had pre-diabetes at entry. Twenty-three subjects (70%) received the maximum dose, eight (24%) received 1,500 mg. Niacin was well-tolerated. Only four subjects (12%) discontinued study treatment. There were small increases in fasting glycaemia and insulin resistance estimated by the homeostasis model assessment, but insulin resistance measures from the 2-h oral glucose tolerance test only transiently worsened. No subject developed persistent fasting hyperglycaemia; one had persistently elevated 2-h glucose >11.1 mmol/l. There were no significant changes in serum transaminases or uric acid. At week 48, the median change in fasting lipid levels in mmol/l (interquartile range) were: total cholesterol -0.21 (-1.35, -0.05), HDL-C +0.013 (-0.03,+0.28), non-HDL-C -0.49 (-1.37,+0.08) and triglycerides -1.73 (-3.68, -0.72). Favourable changes in large HDL and large very low density lipoprotein particle concentration were observed by nuclear magnetic resonance spectroscopy. CONCLUSIONS: ERN in doses up to 2,000 mg daily was safe, well-tolerated and efficacious in HIV-infected subjects with atherogenic dyslipidaemia. Increases in glycaemia and insulin resistance tended to be transient.

Transdisciplinary research and collaboration is widely acknowledged as a critical success factor for solution-oriented approaches that can tackle complex sustainability challenges, such as biodiversity loss, pollution, and climate-related hazards. In this context, city governments' engagement in transdisciplinarity is generally seen as a key condition for societal transformation towards sustainability. However, empirical evidence is rare. This paper presents a self-assessment of a joint research project on ecosystem services and climate adaptation planning (ECOSIMP) undertaken by four universities and seven Swedish municipalities. We apply a set of design principles and guiding questions for transdisciplinary sustainability projects and, on this basis, identify key aspects for supporting university-municipality collaboration. We show that: (1) selecting the number and type of project stakeholders requires more explicit consideration of the purpose of societal actors' participation; (2) concrete, interim benefits for participating practitioners and organisations need to be continuously discussed; (3) promoting the 'inter', i.e., interdisciplinary and inter-city learning, can support transdisciplinarity and, ultimately, urban sustainability and long-term change. In this context, we found that design principles for transdisciplinarity have the potential to (4) mitigate project shortcomings, even when transdisciplinarity is not an explicit aim, and (5) address differences and allow new voices to be heard. We propose additional guiding questions to address shortcomings and inspire reflexivity in transdisciplinary projects.

Summary 1. The distribution of species is affected by many factors operating at a variety of temporal and spatial scales in a heterogeneous landscape. In lakes, fish communities are dynamic, influenced by landscape‐level factors that control colonisation and extinction. 2. We used classification and regression tree (CART) analyses to quantify the importance of landscape‐level factors in determining the distribution of fish species in 168 arctic Alaskan lakes. Factors including lake size, depth, outflow gradient, distance to other lakes, lake order, altitude, river drainage and age of glacial surface were analysed. These factors could affect either access of fish to a lake (colonisation variables), or their survival in a lake that already had been colonised (extinction variables). 3. The presence of a species was predicted accurately in 78.4% ± 10.5% (mean ± SD) of cases, and absence in 75.0% ± 6.1% of cases. The relative importance of extinction versus colonisation variables varied with species. Extinction variables were most important for lake trout ( Salvelinus namaycush ) and slimy sculpin ( Cottus cognatus ), a mixture of extinction and colonisation variables was important for arctic char ( Salvelinus alpinus ), and colonisation variables were most important for arctic grayling ( Thymallus arcticus ) and round whitefish ( Prosopium cylindraceum ). 4. Ecological differences among species account for much of the difference in relative importance of colonisation versus extinction variables. In addition, stream piracy events have occurred over geologic time scales, which have resulted in lakes that are currently inaccessible but support relict fish populations. 5. Climate warming, currently occurring in the arctic, is likely to alter further the stream network, which could have dramatic effects on fish distributions by affecting access to isolated lakes or isolating lakes that are currently accessible.