Arctic Habitats Research Articles

Meiobenthos in marine coastal sediments

Abstract The term meiobenthos refers to a group of invertebrate organisms that are intermediate in size between macro- and microfauna, and inhabit all sediment types in all marine environments and in all climatic zones. They may occur at enormously high densities of millions of individuals per square metre; this means that 10 cm 3 of sediment in any given habitat may contain thousands of these organisms. Although meiobenthos in some extreme arctic habitats is uncommonly poor, the abundance and composition of the polar or subpolar meiobenthic assemblages are not essentially different from those found in boreal–tropical locations at corresponding sediments and depths.

Growth of the alpine herb Rumex alpinus over two decades: effect of climate fluctuations and local conditions

Plants in arctic and alpine habitats could potentially escape the effects of climatic fluctuations by surviving in suitable microsites. We tested this hypothesis by conducting a herb-chronological analysis of the morphological growth markers retained on the rhizomes of the clonal herb Rumex alpinus—a common plant with a broad ecological amplitude found in the alpine zone of the Low Tatra Mts., Western Carpathians, Slovakia. We asked whether aspects of plant growth were related to the climatic conditions measured at a local weather station over two approximately decade-long study periods (1977–1988 and 2001–2010) on both snowbed and non-snowbed sites. Although the latter period had average summer temperatures that were about 2 °C warmer than the first, both had the same average growing season length and average total monthly precipitation. Snow accumulation and other climatic events shortened the growing seasons for the plants in the first period, thus reducing vegetative growth. On the other hand, climatic events prolonging the growing seasons supported plant growth and flowering in the snowbed site. In the second, warmer period, growing season lengths were not related to plant performance but August temperatures had a positive effect on plant growth in both the snowbed and non-snowbed sites. Our results imply that mesoclimatic factors substantially affect plant growth, although their relative importance might change with climate fluctuations altering their influence in sites of differing snow accumulation.

A hybrid zone between Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii)

ABSTRACT. We studied patterns of geographic variation in structural size and genetic characteristics of white-cheeked geese inhabiting coastal areas of Hudson Bay, Canada, from northern Manitoba to southern Nunavut to determine the degree of morphological and spatial overlap, if any, between Cackling Geese (Branta hutchinsii) and Canada Geese (B. canadensis) in this region. Most Canada Geese occurred in sub-Arctic habitats south of 59°N latitude, and most Cackling Geese occurred in Arctic habitats north of 60°N, but the two species overlapped in a narrow zone between 59°N and 60°N latitude that coincided with the ecotone between sub-Arctic and Arctic ecozones. Mismatches between morphological and genetic characteristics of some individual females suggested that introgression had occurred in this area, and contrasting patterns in the nuclear and mitochondrial DNA (mtDNA) were consistent with female natal philopatry and male-biased dispersal. Evidence of introgression in the nuclear genome was geographicall...

Equisetum variegatum Schleich. ex Weber et Mohr in Lithuania: habitat diversity, distribution patterns and environmental status based on herbarium collection

Equisetum variegatum Schleich. ex Weber et Mohr (Equisetaceae L. Rich. ex DC.) is a perennial evergreen plant with a long rhizome. It grows in Arctic tundra and mountain habitats. Usually E. variegatum is assigned to rare or fairly frequent plant species in Lithuania. During the last six decades the number of E. variegatum localities increased more than tenfold. Therefore it is important to perform an analysis of E. variegatum distribution patterns, diversity of localities, and environment protection status in Lithuania. In order to analyse E. variegatum distribution and habitats, herbarium specimens of the horsetail in four Lithuanian herbaria as well as the data obtained during personal research were used. The analysis showed that E. variegatum is found in 27 of 60 administrative districts of Lithuania. Approximately 70% of E. variegatum habitats are anthropogenic, found mainly in the abandoned sand or gravel quarries. Three naturally occurring E. variegatum habitat concentration zones were determined in south-eastern and western Lithuania as well as on the coast. Typical naturally occurring E. variegatum habitats in Lithuania are wet meadows, lake shores, fen, coastal dunes, and pine forests. E. variegatum is rare or very rare in natural habitats and fairly rare or fairly common in anthropogenic habitats in Lithuania. In the latter habitats E. variegatum frequently forms thicket.

Spatial modelling of Arctic plant diversity

Habitat suitability and species distribution models have both become essential tools in biodiversity conservation and management. However, very few of these studies exist from Arctic habitats and hardly any on Arctic species diversity modelling. The basic goal of this study was to develop a statistical model based on vascular plant species’ spatial distribution data on the Svalbard archipelago and their dependence on a set of available environmental variables. The obtained model was then implemented into GIS, enabling us to calculate plant diversity indices for the Svalbard archipelago. Svalbard is easily accessible for research and contains well-known flora with plentiful ancillary data layers available. This location thus constitutes a suitable study area for analysing and modelling biodiversity. Georeferenced data on vascular plant species diversity were gathered from 184 study sites widely distributed on the archipelago. Thirteen environmental raster layers were generated based on a digital elevation model, a geological map, as well as climatic and remote sensing data. Environmental data were extracted from the raster layers at each of the 184 field study plots. Both field study plots and raster layers were studied at 1 km2 resolution. Analysis using forward stepwise multiple regression revealed that growth season temperature sum (GDD), mean July precipitation (PREC) and the vegetation indices ‘normalised deviation vegetation index’ (NDVI) are the best predictors of Svalbard's vascular plant biodiversity. Despite a 48% precision of the statistical model in predicting Shannon diversity index (SDI), the output map seems to reflect well the expected distribution based on knowledge of the influence of the environmental variables considered. All variables in the model, and most other data tested in the model, are easily available and with global coverage.

Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network

A protected area network should ensure the maintenance of biodiversity. Because of climate change, species ranges are expected to move polewards, causing further demand for the protected area network to be efficient in preserving biota. We compared population changes of different bird species groups according to their habitat preferences in boreal protected areas in Finland on the basis of large-scale censuses carried out in 1981–1999 and in 2000–2009. Population densities of common forest habitat generalists remained the same between the two periods, while densities of species of conservation concern showed contrasting trends: species preferring old-growth forests increased, but those living on mires and wetlands, and species of Arctic mountains decreased. These trends are most probably connected with climate change, but successional changes in protected areas and regional habitat alteration should also be taken into account. Of species preferring old-growth forests, a larger proportion are southern than among species of mires and wetlands, or of Arctic mountains, most or all of which, respectively, had a northerly distribution. In general, northern species have decreased and southern increased with the exception of northern species of old-growth forests which had not declined. On the other hand, bird species of mires and wetlands decreased also in the northernmost protected areas although mires had not been drained in the region in contrast with southern and central Finland thus indicating that regional-scale direct habitat loss did not cause the decline of these species in the north. It is suggested that climate change effects on species in natural boreal and Arctic habitats most probably are habitat-specific with large differences in response times and susceptibility.

Adaptive strategies and life history characteristics in a warming climate: Salmon in the Arctic?

In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

Peeking through a frosty window: molecular insights into the ecology of Arctic soil fungi

Fungi are ubiquitous in Arctic soils, where they function as symbionts and decomposers and may affect the carbon balance of terrestrial ecosystems subjected to climate change, and yet little is known about soil fungi at high latitudes. Here we review data from recent molecular studies to determine broad patterns in Arctic soil fungal ecology. The data indicate comparatively high fungal diversity in Arctic soils, with currently no evidence for lower species richness at higher latitudes. The dominant fungi, and particularly ectomycorrhizal-forming fungi, appear to be cosmopolitan species. Arctic soil fungi are capable of growth at sub-zero temperatures, melanized forms are frequent, host specificity is low and there is evidence that community composition alters under experimental warming. Future challenges are to determine the drivers of fungal diversity, whether or not diversity alters at higher latitudes and how apparently cosmopolitan fungi are able to survive the extreme environments encountered in Arctic habitats.

Impacts of Grazing and Climate Warming on C Pools and Decomposition Rates in Arctic Environments

Arctic ecosystems are important habitats for Arctic breeding geese which in their turn have a profound impact on the vegetation in these areas. The herbivore pressure is currently on the rise in the region and may interact with climate change to drive changes in both productivity and decomposition rates. In this study, we aim to determine the combined impact of warming and geese on C pools and decomposition in two high Arctic habitats, mesic heath and wet meadow. We employed field-experimental warming and grazing treatments in a fully factorial design and quantified their impact on ecosystems C pools and turnover. High grazing levels reduced vascular biomass and litter C pools at both sites, whereas warming reduced moss biomass at the mesic site only. Grazing increased decomposition rates and reduced the amount of labile C in the soil at the mesic site, whereas warming substantially reduced C concentrations by approximately 25%. Intermediate level of grazing had an opposite effect and resulted in increased soil C storage at the mesic site. In contrast, no effects of the treatment on belowground C cycling were found at the wet site. In conclusion, the two levels of grazing and warming impacted on different aspects of the C cycle investigated in this study. The high grazing and warming treatment promoted reduced carbon storage/decomposition both above- and belowground with the strongest effects seen at the mesic site.

Elemental and fatty acid composition of snow algae in Arctic habitats

Red, orange or green snow is the macroscopic phenomenon comprising different eukaryotic algae. Little is known about the ecology and nutrient regimes in these algal communities. Therefore, eight snow algal communities from five intensively tinted snow fields in western Spitsbergen were analysed for nutrient concentrations and fatty acid (FA) composition. To evaluate the importance of a shift from green to red forms on the FA-variability of the field samples, four snow algal strains were grown under nitrogen replete and moderate light (+N+ML) or N-limited and high light (−N+HL) conditions. All eight field algal communities were dominated by red and orange cysts. Dissolved nutrient concentration of the snow revealed a broad range of NH+4 (<0.005–1.2 mg N l−1) and only low PO3−4 (<18 μg P l−1) levels. The external nutrient concentration did not reflect cellular nutrient ratios as C:N and C:P ratios of the communities were highest at locations containing relatively high concentrations of NH+4 and PO3−4. Molar N:P ratios ranged from 11 to 21 and did not suggest clear limitation of a single nutrient. On a per carbon basis, we found a 6-fold difference in total FA content between the eight snow algal communities, ranging from 50 to 300 mg FA g C−1. In multivariate analyses total FA content opposed the cellular N:C quota and a large part of the FA variability among field locations originated from the abundant FAs C18:1n-9, C18:2n-6, and C18:3n-3. Both field samples and snow algal strains grown under −N+HL conditions had high concentrations of C18:1n-9. FAs possibly accumulated due to the cessation of growth. Differences in color and nutritional composition between patches of snow algal communities within one snow field were not directly related to nutrient conditions. We propose that the highly patchy distribution of snow algae within and between snow fields may also result from differences in topographical and geological parameters such as slope, melting water rivulets, and rock formation.

Antagonistic interaction networks among bacteria from a cold soil environment

Microbial antagonism in an Arctic soil habitat was demonstrated by assessing the inhibitory interactions between bacterial isolates from the same location. Of 139 isolates obtained from five soil samples, 20 antagonists belonging to the genera, Arthrobacter, Pseudomonas and Flavobacterium were identified. Inter-genus, inter-species and inter-strain antagonism was observed between the interacting members. The extent of antagonism was temperature dependent. In some cases, antagonism was enhanced at 4 °C but suppressed at 18 °C while in some the reverse phenomenon was observed. To interpret antagonism from an ecological perspective, the interacting members were delineated according to their positional roles in a theoretical antagonistic network. When only one antimicrobial producer (P) was present, all the other members permitted grouping into either sensitive (S) or resistant (R). Composite interactive types such as PSR, PS, PR or SR could be designated only when at least two producers were present. Mapping of all possible antagonistic interaction networks based on the individual positional roles of the interactive types illustrates the existence of complex and interconnected networks among microbial communities.

The cumulative impacts of climate change on Fraser River sockeye salmon (Oncorhynchus nerka) and implications for management

Anadromous Pacific salmon ( Oncorhynchus spp.) are vulnerable to climate change in both freshwater and marine habitats. I use a qualitative model to assess the cumulative effects of climate change across life stages and generations of Fraser River sockeye salmon ( Oncorhynchus nerka ) and other salmon species. The effects of climate change most relevant to Fraser River sockeye include warming of freshwater and marine habitats, altered hydrology in spawning rivers, reduced productivity in nursery habitats, and changed distribution and phenology of predator and prey species. The weight of evidence indicates that these changes will negatively affect growth and survival of Fraser River sockeye at all life stages. Effects on one life stage will also carry forward to heighten adverse effects at subsequent life stages and across generations so that the cumulative impact is greater than the impact on individual stages. Salmon can adapt to climate change but probably not enough to sustain productivity. In the south, focus of policy and management on conserving and enhancing resilience is needed to retain some salmon production. At the same time, Arctic habitats are becoming accessible to salmon. Management in the Arctic should protect potentially productive habitats from development and facilitate their colonization by Pacific salmon.

Red fox takeover of arctic fox breeding den: an observation from Yamal Peninsula, Russia

Here, we report from the first direct observation of a red fox (Vulpes vulpes) intrusion on an arctic fox (Vulpes lagopus) breeding den from the southern Arctic tundra of Yamal Peninsula, Russia in 2007. At the same time, as a current range retraction of the original inhabitant of the circumpolar tundra zone the arctic fox is going on, the red fox is expanding their range from the south into arctic habitats. Thus, within large parts of the northern tundra areas the two species are sympatric which gives opportunities for direct interactions including interference competition. However, direct first-hand observations of such interactions are rare, especially in the Russian Arctic. In the present study, we observed one red fox taking over an arctic fox breeding den which resulted in den abandonment by the arctic fox. On July 19, eight arctic fox pups were observed on the den before the red fox was observed on the same den July 22. The pups were never seen at the den or elsewhere after the red fox was observed on the den for as long as we stayed in the area (until August 10). Our observation supports the view that direct interference with red fox on breeding dens may contribute to the range retraction of arctic foxes from the southern limits of the Arctic tundra in Russia.

A trial of a non-statistical computer program for monitoring fuel reserves, response to wind and other details from GPS tracks of migrating geese

GPS transmitters were used with the Argos satellite system to track two Light-bellied Brent Geese (Branta bernicla hrota) from Iceland to Arctic Canada, three Greenland White-fronted Geese (Anser albifrons flavirostris) from Scotland to west Greenland, and two Barnacle Geese (Branta leucopsis) from Scotland to Spitsbergen. Each goose’s wing span was measured at the time of tagging, and its body mass and fat fraction were estimated at the time of departure. This was the starting point for the Flight program’s time-marching simulation, which is a non-statistical procedure based on flight mechanics. The ground speed was measured between each GPS fix and the previous one, and combined with a wind estimate to find the air speed. The program calculated the power, using the air density from the GPS altitude. The rates of consumption of fat and muscle tissue were calculated from the power, and used to update the body mass and composition. The total air distance flown by each bird was not consistently less than the ground distance, and there was no indication that the birds could select their routes, or even their timing, so as to bias the wind in their favour. Rates of climb when ascending the Greenland Ice Cap were very low in the Brent Geese, in relation to the maximum rate of climb of which the flight muscles were expected (on mechanical grounds) to be capable of supporting. The Brent Geese stopped often during the ice crossing, suggesting that they could not sustain sufficient aerobic power for continuous flight. The fat fractions of the White-fronted Geese were lower across the ice cap, and they climbed faster and stopped less often. Energy height was used as a species-independent measure of energy reserves. All seven northbound geese arrived in their nesting areas at estimated energy heights exceeding 200 km (around 350 km for the two Brent Geese). All of the geese achieved average energy gradients of at least 11, including short stops, meaning that their arrival energy heights were sufficient to fly a further 2,200–4,000 km. We propose that these reserves represent the energy height needed to initiate successful breeding in these arctic habitats, with an element of insurance against contrary winds.

Two mechanisms of aquatic and terrestrial habitat change along an Alaskan Arctic coastline

Arctic habitats at the interface between land and sea are particularly vulnerable to climate change. The northern Teshekpuk Lake Special Area (N-TLSA), a coastal plain ecosystem along the Beaufort Sea in northern Alaska, provides habitat for migratory waterbirds, caribou, and potentially, denning polar bears. The 60-km coastline of N-TLSA is experiencing increasing rates of coastline erosion and storm surge flooding far inland resulting in lake drainage and conversion of freshwater lakes to estuaries. These physical mechanisms are affecting upland tundra as well. To better understand how these processes are affecting habitat, we analyzed long-term observational records coupled with recent short-term monitoring. Nearly the entire coastline has accelerating rates of erosion ranging from 6 m/year from 1955 to 1979 and most recently peaking at 17 m/year from 2007 to 2009, yet an intensive monitoring site along a higher bluff (3–6 masl) suggested high interannual variability. The frequency and magnitude of storm events appears to be increasing along this coastline and these patterns correspond to a greater number of lake tapping and flooding events since 2000. For the entire N-TLSA, we estimate that 6% of the landscape consists of salt-burned tundra, while 41% is prone to storm surge flooding. This offset may indicate the relative frequency of low-magnitude flood events along the coastal fringe. Monitoring of coastline lakes confirms that moderate westerly storms create extensive flooding, while easterly storms have negligible effects on lakes and low-lying tundra. This study of two interacting physical mechanisms, coastal erosion and storm surge flooding, provides an important example of the complexities and data needs for predicting habitat change and biological responses along Arctic land–ocean interfaces.

Home range dynamics of mountain hare (&lt;em&gt;Lepus timidus&lt;/em&gt;) in the Swiss Alps

Little is known on the ecology and behaviour of the alpine mountain hare (Lepus timidus). Between 1996 and 1997, we analysed by radiotracking the pattern of space use of 8 mountain hares from the Swiss Alps. We estimated home range size using both the kernel density estimator and the minimum convex polygon. We found smaller ranges (38 ha) compared to those reported for the species in boreal or arctic habitats, but similar to ranges in Scotland. Hares did not use a centre of major activity (core area) and showed high home range overlap, confirming their non-territorial behaviour. Smaller ranges were used during winter compared to the other seasons, whilst no difference in size was found between sexes.

A Bird’s-Eye View of Arctic Governance: Reflecting on the Role of International Law in Arctic Cooperation from a Bird Conservation Perspective

Abstract This article discusses the role of international law in environmental governance in the Arctic. It does so from the perspective of bird conservation. Challenges in the latter field are introduced, including the impact of climate change on Arctic bird habitats and the incidental mortality of seabirds in Arctic fisheries. The ability of the current international legal framework in the Arctic to meet these challenges is scrutinised, and future scenarios for its enhancement are explored, including the conclusion of (a) new legally binding agreement(s). Five species receive particular attention as part of this exercise: gyrfalcon (Falco rusticolus), ivory gull (Pagophila eburnea), spoon-billed sandpiper (Eurynorhynchus pygmeus), Kittlitz’s murrelet (Brachyramphus brevirostris) and Brünnich’s guillemot (Uria lomvia). Special attention is also devoted to the issue of seabird bycatch.

Cold climate plants in a warmer world

The present cold adapted floras of arctic and alpine regions are frequently considered as being at risk from climatic warming. However, the prospect of higher temperatures liberating large areas of land from permanent ice cover in the Arctic plus a retreat of the nival zone on higher mountains could provide new terrain for the continued existence and expansion of both arctic and alpine floras. Examination in detail of these floras reveals numerous examples of species that have sufficient genetic variability to adapt phenologically and physiologically to warmer and drier conditions. The calcicole flora of the Alps is well placed to withstand the drier conditions that may arise with climatic warming. In the Arctic the polar night will persist whatever changes may take place in the temperature regime. There will therefore always be features of the arctic environment that will be distinctive and can be expected to provide a habitat for a polar flora. The polar bear with its complete dependence on sea ice for hunting seals may disappear. However, cold climate floras by contrast will find sufficient heterogeneity in the arctic and alpine habitats and variation within species to evolve and provide adapted species that may benefit from higher temperatures and longer growing seasons.

Molecular diversity assessment of arctic and boreal Agaricus taxa

We provide a phylogenetic diversity assessment study in genus Agaricus as part of our ongoing work to saturate ITS and LSU rDNA sequence diversity of soil-dwelling fungi in Alaska. Pairwise sequence similarity-based groupings and statistical parsimony analyses were applied to delimit operational taxonomic unit (OTU) and were compared to results of full phylogenetic analyses. Our results show that the proportion of section Arvenses taxa is particularly high in the boreal forest and hypo-arctic (low arctic) regions, whereas the genus is represented by section Agaricus in high arctic habitats. Furthermore our findings suggest that the commercially important A. bisporus occurs naturally in the boreal region of interior Alaska, substantially expanding the known northern limit of the species. Delimitations of OTU varied greatly with different methods. In general 95% similarity-based grouping proved to be the least sensitive method, often resulting in section- and subsection-level groups. The 95% connection-limit statistical parsimony separated far more groups. The 98% similarity-based groups and the 98% connection limit networks recognized respectively 11 and 13 OTU containing our specimens. The 98% connection limit statistical parsimony was the only method in which all recognized OTU consisted of members grouped by branches with significant (> .95) posterior probabilities, providing an independent support for the groups. Our results also point out that considerable additional efforts will be needed to elucidate the evolution of this diverse genus and to assess its phylogenetic diversity, given that most taxa in our analyses could not be placed convincingly within well characterized species using ITS/LSU data.

ARCTIC MARINE MAMMALS AND CLIMATE CHANGE: IMPACTS AND RESILIENCE

Evolutionary selection has refined the life histories of seven species (three cetacean [narwhal, beluga, and bowhead whales], three pinniped [walrus, ringed, and bearded seals], and the polar bear) to spatial and temporal domains influenced by the seasonal extremes and variability of sea ice, temperature, and day length that define the Arctic. Recent changes in Arctic climate may challenge the adaptive capability of these species. Nine other species (five cetacean [fin, humpback, minke, gray, and killer whales] and four pinniped [harp, hooded, ribbon, and spotted seals]) seasonally occupy Arctic and subarctic habitats and may be poised to encroach into more northern latitudes and to remain there longer, thereby competing with extant Arctic species. A synthesis of the impacts of climate change on all these species hinges on sea ice, in its role as: (1) platform, (2) marine ecosystem foundation, and (3) barrier to non-ice-adapted marine mammals and human commercial activities. Therefore, impacts are categorized for: (1) ice-obligate species that rely on sea ice platforms, (2) ice-associated species that are adapted to sea ice-dominated ecosystems, and (3) seasonally migrant species for which sea ice can act as a barrier. An assessment of resilience is far more speculative, as any number of scenarios can be envisioned, most of them involving potential trophic cascades and anticipated human perturbations. Here we provide resilience scenarios for the three ice-related species categories relative to four regions defined by projections of sea ice reductions by 2050 and extant shelf oceanography. These resilience scenarios suggest that: (1) some populations of ice-obligate marine mammals will survive in two regions with sea ice refugia, while other stocks may adapt to ice-free coastal habitats, (2) ice-associated species may find suitable feeding opportunities within the two regions with sea ice refugia and, if capable of shifting among available prey, may benefit from extended foraging periods in formerly ice-covered seas, but (3) they may face increasing competition from seasonally migrant species, which will likely infiltrate Arctic habitats. The means to track and assess Arctic ecosystem change using sentinel marine mammal species are suggested to offer a framework for scientific investigation and responsible resource management.