Assessment of the potential of the rock gunnel (Pholis gunnellus) along the Atlantic coast of Canada as a species for monitoring the reproductive impacts of contaminant exposures

Evaluating the impacts of point source discharges on fish species in estuarine environments can be challenging because of a paucity of resident species. We evaluated the biology of rock gunnel (Pholis gunnellus) at three relatively uncontaminated sites in the Bay of Fundy, along the Atlantic coast of Canada. Rock gunnel are seasonally resident (April to November) in tide pools, but little was known about their life history in Atlantic Canada or their potential for use for monitoring environmental quality. Fish were collected between April and November, and ranged from 2.46 g--15.2~g in weight and 97 mm-170 mm in length, with a maximum age of 7 years. Both males and females were similar in size, and both reached sexual maturity at a size of 5.5 g. Organ weights and condition indices of fish were stable from spring when they returned from offshore (April to May) until late summer (August to September), but fall fish (October to November) had slightly larger gonads, livers and condition indices. Rock gunnel may be a useful indicator to provide insight into local impacts of point sources over a short time period. However, they do not provide adequate information on reproductive development and performance since they are not exposed to onshore contaminants during the periods of gonadal development that have most commonly found to be sensitive to anthropogenic stressors.     

Biomarker responses associated with halogenated organic contaminants in northern fulmars (Fulmarus glacialis) breeding in the Canadian Arctic

We examined relationships between hepatic concentrations of halogenated organic contaminants and ethoxyresorufin O-deethylase (EROD) activity and retinoid (vitamin A) concentrations in livers, as well as retinol and thyroid hormone (TT₃, TT₄) levels in blood plasma, of northern fulmars at two breeding colonies in the Canadian High Arctic. Biomarker levels or responses did not differ significantly between males and females at either colony, nor was there any significant difference between colonies. No significant relationships were found between thyroid hormone or hepatic retinoid concentrations and any of the dioxin-like compounds or their Toxic Equivalents (TEQs) although significant positive correlations were found with plasma retinol (p < 0.03). EROD activity was significantly correlated with hepatic dioxin-like compounds and their TEQs (p < 0.001) as well as total PCBs (p < 0.01), which suggests that EROD induction occurs in northern fulmars at environmentally-relevant concentrations.     

Relationship between atmospheric pollution processes and synoptic pressure patterns in northern China

The air pollution index (API) sequences in 10 cities in northern China and the synoptic pressure patterns during autumn and winter from 2002 to 2006 were analyzed with diagnostic and statistical methods. The results showed that the air qualities in northern China had a prominent correlation with the pressure systems. It revealed that (a) the increasing phase of API was associated with high pressure and the successive low pressure, (b) the preceding part of front (i.e. the retral part of low pressure) was associated with the maximum of API values during a cycle of air pollution process, (c) the pressure systems with high gradient led to the decrease of API, and (d) the synoptic pressure patterns and their evolvements were the main causes of regional air pollution processes. These relations can be used to analyze the variation characteristics and mechanism of regional atmosphere pollution process, and provide important basis for the qualitative prediction, control, and management of regional air pollution problems.     

我国北方沙尘暴与植被覆盖度关系研究

利用NOAA/AVHRR和旬归一化植被指数NDVI数据,计算了1983-2000年中国北方13省市区的植被覆盖度,分析了这些地区植被覆盖度的时间变化趋势和空间分布规律,研究了中国北方沙尘暴与植被覆盖度之间的关系。结果表明:我国北方沙尘灾害频次与植被覆盖度有很好的对应关系,1983-2000年的18年间,我国北方大部分地区植被覆盖度增加,这段时期沙尘灾害频次总体呈降低趋势,其中20世纪80年代我国北方大部分地区植被覆盖度增加,这一时期我国北方沙尘暴发生频数下降;20世纪90年代,我国北方大部分区域植被覆盖度呈下降趋势,特别是华北和西北干旱与半干旱地区,下降趋势显著,这一时期我国北方沙尘暴发生频数在减少中有回升趋势。研究结果表明,植被覆盖度是影响中国北方沙尘暴频次变化的重要因素。     

Beyond the black box: Forest sector vulnerability assessments and adaptation to climate change in North America

In the wake of the failures to date of well-publicized multilateral and multi-sectoral mitigation efforts to control greenhouse gases, attention is now increasingly focused on the effectiveness and capacity of national and sub-national level sectoral plans, including forestry, to usher in a new era of adaptation efforts. In Canada, the government of British Columbia spent several years developing its Future Forest Ecosystems Initiative as part of a larger climate change response strategy in the forest sector. Similarly, in the United States, wildfire related events have led to climate change inspired efforts by individual states (e.g., Alaska, California) and the US Forest Service has recently undertaken plans to incorporate climate change considerations in national forest planning beginning with the National Road Map for Responding to Climate Change. This paper highlights a number of shortcomings with both these national and sub-national strategies with respect to the relationships existing between governance, forestry and climate change. It proposes incorporating considerations of governance mechanisms directly into forest sector planning and the need to assess not only natural system level changes but also the extent to which new problems can be dealt with by ‘old’ or ‘new’ governance arrangements.     

Pattern and Process in Northern Rocky Mountain Headwaters: Ecological Linkages in the Headwaters of the Crown of the Continent1

Abstract: The Crown of the Continent is one of the premiere ecosystems in North America containing Waterton‐Glacier International Peace Park, the Bob Marshall‐Great Bear‐Scapegoat Wilderness Complex in Montana, various Provincial Parks in British Columbia and Alberta, several national and state forest lands in the USA, and Crown Lands in Canada. The region is also the headwater source for three of the continent’s great rivers: Columbia, Missouri and Saskatchewan that flow to the Pacific, Atlantic and Arctic Oceans, respectively. Headwaters originate in high elevation alpine environs characterized by high snow accumulations in winter and rainstorms in summer. Most headwaters of the region contain high quality waters with few ions in solution and extremely low nutrient concentrations. Alpine streams have few species of aquatic organisms; however, they often possess rare species and have hydrogeomorphic features that make them vulnerable to climatic change. Subalpine and valley bottom streams of the Crown of the Continent Ecosystem (CCE) flow through well forested watersheds. Along the elevation gradient, the streams and rivers of the CCE flow through series of confining and nonconfining valleys resulting in distinct canyon and floodplain reaches. The alluvial floodplains are characterized by high species diversity and bioproduction maintained by the hydrologic linkages of habitats. The streams and rivers of the CCE have low nutrient concentrations, but may be significantly affected by wildfire, various resource extraction activities, such as logging or mining and exurban encroachment. Wildfire has been shown to increase nutrient loading in streams, both during a fire and then following the fire for as much as 5 years. Logging practices increase nutrient loading and the algal productivity of stream periphyton. Logging and associated roads are also known to increase sediment transport into Crown of the Continent streams directly affecting spawning success of native trout. The CCE is one of the fastest growing regions in the USA because of the many recreational amenities of the region. And, while the region has many remarkably pristine headwater streams and receiving rivers, there are many pending threats to water quality and quantity. One of the most urgent threats comes from the coal and gas fields in the northern part of the Crown of the Continent, where coal deposits are proposed for mountain‐top removal and open‐pit mining operations. This will have significant effects on the waters of the region, its native plants and animals and quality of life of the people.     

Climate change and changes in global precipitation patterns: what do we know?

The objective of this paper is to synthesize the large literature recording changing patterns of precipitation in the observed data, thus indicating that climate change is already a reality. Such a synthesis is required not only for environmental researchers but also for policy makers. The key question is the broad picture at major regional and continental levels. Some interesting conclusions for this survey are emerging. For example, the review shows increased variance of precipitation everywhere. Consistent with this finding, we observe that wet areas become wetter, and dry and arid areas become more so. In addition, the following general changing pattern is emerging: (a) increased precipitation in high latitudes (Northern Hemisphere); (b) reductions in precipitation in China, Australia and the Small Island States in the Pacific; and (c) increased variance in equatorial regions. The changes in the major ocean currents also appear to be affecting precipitation patterns. For example, increased intensity and frequency of El Ni?o and ENSO seem associated with evidence of an observed "dipole" pattern affecting Africa and Asia, although this time series is too short so far. But the changing pattern calls for renewed efforts at adaptation to climate change, as the changing precipitation pattern will also affect the regional availability of food supply.     

Plains cottonwood's last stand: can it survive invasion of Russian olive onto the Milk River, Montana floodplain?

Russian olive (Elaeagnus angustifolia L.) was introduced in 1950 onto one site on the Milk River floodplain, northern Montana, 10 km downstream from the Canada/United States border. To analyze dispersal of Russian olive from the point source between 1950 and 1999, we compared distribution, numbers, size structure, and mortality of Russian olive and plains cottonwood (Populus deltoides Marsh:) on an unregulated reach of the Milk River floodplain in southeastern Alberta and north-central Montana. Within 50 years, Russian olive in this reach has moved upriver into Alberta and downriver to the Fresno Reservoir. It is now present on 69 of the 74 meander lobes sampled, comprising 34%, 62%, and 61% of all Russian olive and plains cottonwood seedlings, saplings, and trees, respectively. On some meander lobes, Russian olive has colonized similar elevations on the floodplain as plains cottonwood and is oriented in rows paralleling the river channel, suggesting that recruitment may be related to river processes. Breakup ice had killed 400 Russian olive saplings and trees and damaged >1000 others on 30 of the meander lobes in 1996. Nevertheless, Russian olive now outnumbers cottonwood on many sites on the Milk River floodplain because its seeds can be dispersed by wildlife (particularly birds) and probably by flood water and ice rafts; seeds are viable for up to 3 years and germination can take place on bare and well-vegetated soils; and saplings and trees are less palatable to livestock and beaver than plains cottonwood. Without control, Russian olive could be locally dominant on the Milk River floodplain in all age classes within 10 years and replace plains cottonwood within this century.     

北太平洋地区沙尘沉降与海洋生物兴衰的关系

通过对2001年4月中亚强沙尘暴过程在中国、韩国、日本和北美大陆地面PM10观测结果进行统计分析,推算出了北太平洋PAPA地区的沙尘沉降通量,结合同期PAPA地区的海洋表层有机碳和叶绿素观测结果,探讨了北太平洋沙尘与海洋生物兴衰的关系.结果表明,本次强沙尘暴过程可以给PAPA地区带去大约3.1～5.8μg/m³的风成Fe元素,它激发了海洋生物泵,引起海洋浮游植物的快速繁盛.     

Mass balanced and dynamic simulations of trophic models of kelp ecosystems near the Mejillones Peninsula of northern Chile (SE Pacific): Comparative network structure and assessment of harvest strategies

Mass balanced trophic models for kelp ecosystems which include subsystems dominated by Macrocystis integrifolia, Lessonia trabeculata and areas of barren ground (BG) were constructed for subtidal areas near the Mejillones Peninsula (SE Pacific), Chile. Information on biomass, P/B ratios, catches, food spectrum, consumption and dynamics of commercial and non-commercial populations was obtained and examined using Ecopath with Ecosim software analyses. The biomass of blades of L. trabeculata and M. integrifolia represented the compartments most relevant to the subsystems studied. Within the herbivores, the sea urchin Tetrapigus niger was dominant, followed by the snails Turritella sp. and Tegula sp. The fishes Pinguipes chilensis and Cheilodactylus variegatus were the dominant predators, followed by the asteroids Heliaster helianthus and Meyenaster gelatinosus. The highest system throughput (72,512 g wet weight m⁻² year⁻¹) was calculated for the subsystem dominated by M. integrifolia. The mean trophic level of the catch ranged from 1.1 (subsystem dominated by L. trabeculata) to 1.3 (subsystem dominated by M. integrifolia) to 3.2 (barren ground subsystem), showing that harvesting in each system was concentrated either on primary producers (blades of kelp species) or top predator fishes. Although the values for the Relative Ascendency (A/C) fluctuated from 36.5 to 45%, suggesting that all the systems were immature, the subsystem dominated by M. integrifolia emerged as the least resistant to external disturbances (e.g. fisheries). This result agreed with the high value of the system recovery time (SRT) for the M. integrifolia subsystem as a response to combined fisheries scenarios. The results obtained using mixed trophic impact (MTI) and Ecosim [increasing the fishing mortality F_i by 4×] showed that in most of the cases the predictions had the same qualitative tendencies. One of the most important results obtained in this study was that exploitation of kelp blades as an alternative strategy to harvesting the whole plants appeared to be ecologically sustainable, since harvesting the blades propagated only small effects on the entire subsystem. The fish P. chilensis may be considered as a top predator species with a strong top-down control since an increase in its fishing mortality in the subsystem dominated by M. integrifolia produced a high SRT value, and the F_MSY was less than the originally entered F_i in Ecopath. Based on the results obtained, it was concluded that the trophic mass balanced models and simulated management scenarios offered good possibilities for the planning of interventions and manipulations or the planning of more sustainable management strategies in highly disturbed natural systems.