River Wyre - a migratory salmonid river

This report has been prepared in response to a request from the National Rivers Authority. It produces a broad assessment of the River Wyre as a migratory salmonid river based on a site visit and the documentation provided, and looks at objectives of the Wyre salmon and sea trout restoration group. It also looks at ways for habitat improvement and recommends other possible means of fisheries management development for the River Wyre.

Sensitivity of angler benefit estimates from a model of recreational demand to the definition of the substitute sites considered by the angler

Fishery managers are mandated to understand the effects that environmental damage, fishery regulations, and habitat improvement projects have on the net benefits that recreational anglers derive from their sport. Since 1994, the National Marine Fisheries Service (NMFS) has worked to develop a consistent method for estimating net benefits through site choice models of recreational trip demand. In estimating net benefits with these models, there is a tradeoff between computational efficiency and angler behavior in reality. This article examines this tradeoff by considering the sensitivity of angler-welfare estimates for an increase in striped bass (Morone saxatalis) angling quality across choice sets with five travel distance cutoffs and compares those estimates to a model with an unrestricted choice set. This article shows that 95% confidence intervals for welfare estimates of an increase in the striped bass catch and keep rate overlap for all distance-based choice sets specified here.

The Feasibility of Enhancing Red Sea Urchin, Strongylocentrotus iranciscanus, Stocks in California: An Analysis of the Options

The California fishery for red sea urchins, Strongylocentrotus franciscanus, has undergone explosive growth in recent years and is approaching full exploitation. Thus, there is considerable interest in enhancing stocks to maintain a high rate of landings. Fishable stocks of red sea urchins in different areas appear to be limited at three stages in their life history: By the availability of larvae, by the survival of newly settled to mid-sized animals, and by the food available to support growth and reproduction of larger animals. Here I review other efforts, notably the extensive Japanese work, to enhance fishable stocks of benthic marine invertebrates, and consider the potential options for red sea urchins at different points of limitation. These include collecting or culturing seed for outplanting, physical habitat improvement measures, improving the food supply, and conservation measures to protect existing stocks until alternate methods are proven and in place. The options are compared in terms of biological feasibility, capital and labor requirements, and potential implications for change in the structure of the fishing industry.

A report on the strategic fisheries stock assessment survey of the minor catchments in South West Cumbria 1996 with particular reference to salmonids

This is the report on the strategic fisheries stock assessment survey of the minor catchments in South West Cumbria 1996 with particular reference to salmonids, produced by North West Water in 1994. The 1996 Minor Catchment survey indicates variations in salmonid production within these catchments. Survey results indicate that production may be reaching its limit in certain areas whilst others are underachieving and others are unsuitable for salmonid production. Trout production within the catchments is higher and more widespread than that of salmon. Water quality levels vary considerably between catchments and intra-annually within individual catchments. The need for selective habitat surveys, with a view to habitat improvement schemes (H.I.S) is discussed. This report formed a basis for subsequent reports, thus, allowing data comparisons and analysis of production level fluctuations. It was the most extensive assessment of these catchments to date, taking into account comparisons with the new National Database on salmonid production in England and Wales.

The River Teign SAP Consultation Document

This is the River Teign Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Teign Salmon Action Plan (SAP). This approach to salmon management within the England and Wales introduces the concept of river-specific Conservation Limits as a method of assessing the status of the salmon stock. The River Teign Salmon Action Plan follows the format of those completed for the Rivers Torridge, Taw and Dart. It is the fourth of eight action plans that will be produced for salmon rivers within the Devon Area Fisheries, Recreation and Biodiversity Team. The River Teign SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery. The Teign salmon stock is currently failing to meet its conservation limit. This failure is largely attributed to the reduction in the survival rate during the marine phase of the salmon life cycle. This is likely to constrain stocks to lower levels than have existed historically. Still further catch controls may contribute to a reduction in exploitation rates and allow stocks to recover to meet their conservation limit. Other important actions include the continuation of habitat improvement works which aim to maximise spawning habitat utilisation, spawning success, and juvenile survival and production.

森林管理对动物生境影响的模拟研究——以小兴安岭友好林业局为例

理解森林管理对野生动物生境的累积效应，需要对不同森林管理预案作出预测、分析和评价。本文，以小兴安岭友好林业局为研究区，利用空间直观景观模型LANDIS模拟其在6种森林管理预案—无采伐、皆伐、择伐I（禁伐区不采伐，限伐区和商品林区每10年采伐面积分别为5%和10%）、择伐II（限伐区和商品林区10%和15%）、造林I（采伐同择伐I，伐后人工更新）和造林II（采伐同择伐II，伐后人工更新）下200年内的森林景观变化。在查阅文献、野外考察和咨询相关专家的基础上，以GIS为平台，构建有着不同生境需求的3种动物：松鼠（Sciurus vulgaris）、马鹿（Cervus elaphus）和花尾榛鸡（Bonasa bonasia）在景观尺度上的生境适宜度指数（Habitat suitability index, HSI）模型，利用Arc的宏语言AML（Arc Macro Language）将LANDIS的输出结果与3种动物的HSI模型相结合，借助生境单元和类水平（Class level）上的景观指数（结合度指数等）评价动物生境，以反映不同森林管理预案对动物生境的影响。研究结果表明： 1）对于LANDIS的模拟结果而言，不同森林管理预案往往导致不同的森林演替动态：无采伐和2造林方案下，森林逐渐向成、过熟林演替，且造林方案显著增加了营林树种的分布面积；择伐I和择伐II下，由于成、过熟林被采伐，森林向后期演替的速度较为缓慢，而皆伐下，中、幼龄林的比重较大。定性而言，对于偏好早期演替的动物而言，皆伐下的生境适宜性较高；对于偏好中、后期演替森林的动物而言，2种择伐方案下生境适宜性较高；对于偏好后期演替的动物而言，无采伐和2造林方案下生境适宜性较高。 2）对于松鼠，无采伐和2造林预案下的生境单元和适宜生境（HSI≥0.5）结合度指数较高，适宜生境的平均斑块面积较大，表明这3种预案下的生境适宜性较高，而2择伐预案由于移去了大量成、过熟林，导致松鼠生境适宜性的下降，对于皆伐，尽管采伐量比2择伐预案的小，由于其不利于针叶林的天然更新，对松鼠的生境破坏更为严重。 3）对于马鹿，皆伐和2造林预案下的生境单元和结合度指数较高，而无采伐下的生境单元和结合度指数整体上又小于2择伐预案下的，这表明，适当的干扰反而利于提高马鹿的生境适宜性，因为，若没有这些采伐、造林等干扰活动，森林的郁闭度会随着树冠的封闭而逐渐加大，下层的许多不耐荫的树种就会消失或减少，降低马鹿的食物来源。 4）对于花尾榛鸡，若不考虑营林活动对其干扰，2造林预案下的生境单元和结合度指数较高，其次为无采伐预案，而皆伐和2择伐方案下较低，这表明，单纯的采伐的将减小花尾榛鸡的生境适宜性。 生态系统是一复杂的系统，因此，不可能存在适于所有动物的森林管理预案，对于管理预案的选择取决于管理者多方面（经济、生态和社会）的权衡。本文是将LANDIS与HSI相结合模拟评估森林管理预案对动物生境影响的一次尝试，研究结果表明了这一方法的实用性。尽管这一方法存在一定的局限性，但利用这一方法，能够可视化和量化结果，并比较不同森林管理预案，从生物多样性保护出发，为森林管理提供决策支持。最后，需要声明的是，本研究侧重方法的探讨，作为实际应用，还需要大量的野外工作来验证HSI模型。

Statistical analysis of extreme forest fires

Forest fires can cause extensive damage to natural resources and properties. They can also destroy wildlife habitat, affect the forest ecosystem and threaten human lives. In this paper extreme wildland fires are analysed using a point process model for extremes. The model based on a generalised Pareto distribution is used to model data on acres of wildland burnt by extreme fire in the US since 1825. A semi-parametric smoothing approach is adapted with maximum likelihood method to estimate model parameters.

Semi-Parametric Analysis of Extreme Forest Fires

Forest fires can cause extensive damage to natural resources and properties. They can also destroy wildlife habitat, affect the forest ecosystem and threaten human lives. In this paper incidences of extreme wildland fires are modelled by a point process model which incorporates time-trend. A model based on a generalised Pareto distribution is used to model data on acres of wildland burnt by extreme fire in the US since 1825. A semi-parametric smoothing approach, which is very useful in exploratory analysis of changes in extremes, is illustrated with the maximum likelihood method to estimate model parameters.

The impact of the Arrábida Marine Park (Portugal) on the decapod crustacean Eualus cranchii: a case study

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Univerisdade do Algarve, 2015

Population Trends of a Mixed-Species Colony of Humboldt and Magellanic Penguins in Southern Chile after Establishing a Protected Area

Worldwide marine protected areas (MPAs) have been designated to protect marine resources, including top predators such as seabirds. There is no conclusive information on whether protected areas can improve population trends of seabirds when these are further exploited as tourist attractions, an activity that has increased in past decades. Humboldt Penguins (Spheniscus humboldti) and Magellanic Penguins (S. magellanicus) breed sympatrically on Puñihuil Islets, two small coastal islands off the west coast of Chiloé Island (41° S) in southern Chile that are subject to exploitation for tourism. Our goal was to compare the population size of the mixed colony of Humboldt and Magellanic Penguins before and after protection from unregulated tourism and freely roaming goats in 1997. For this purpose, two censuses were conducted in 2004 and 2008, and the numbers compared with those obtained in 1997 by other authors. The proportion of occupied, unoccupied, and collapsed/flooded burrows changed between years; there were 68% and 34% fewer collapsed burrows in 2004 and 2008, respectively, than in 1997. For the total number of burrows of both species, we counted 48% and 63% more burrows in 2004 and 2008, respectively, than in 1997. We counted 13% more burrows of Humboldt Penguins in 2008 than in 1997, and for Magellanic Penguins, we estimated a 64% increase in burrows in 2008. Presumably, this was as a result of habitat improvement attributable to the exclusion of tourists and the removal of goats from the islets. Although tourist visits to the islets are prohibited, tourism activities around the colonies are prevalent and need to be taken into account to promote appropriate management.

Marsh deer (Blastocerus Dichotomus) reintroduction in the Jataí Ecological Station (Luís Antônio, SP): spatial preferences

A destruição dos habitats naturais e a extinção de espécies têm crescido muito a partir da última metade do século XX. Nesse contexto, o aumento do número de espécies ameaçadas tem proporcionado maior uso da reintrodução como estratégia de conservação no combate à atual taxa de extinção. O presente trabalho focaliza um estudo de 16 meses realizado com cervos-do-pantanal reintroduzidos na Estação Ecológica de Jataí. Os animais foram marcados com rádio-colares e monitorados diariamente entre dezembro de 1998 e abril de 2000, tendo suas atividades de deslocamento e uso do espaço acompanhadas por triangulação. Os animais exploraram várzeas dentro da unidade de conservação e também uma área de várzea pertencente a uma propriedade particular localizada na fronteira oeste da estação. Durante o período de estudo, a maioria dos cervos reintroduzidos utilizou a área de várzea particular mais intensivamente que as várzeas da unidade de conservação. A preferência demonstrada por essa área confirmou sua importância ecológica, evidenciando a necessidade de proteção por meio de sua incorporação aos limites da Estação Ecológica de Jataí.

Use and Performance of In-Stream Structures for River Restoration: a Case Study from North Carolina

In-stream structures including cross-vanes, J-hooks, rock vanes, and W-weirs are widely used in river restoration to limit bank erosion, prevent changes in channel gradient, and improve aquatic habitat. During this investigation, a rapid assessment protocol was combined with post-project monitoring data to assess factors influencing the performance of more than 558 in-stream structures and rootwads in North Carolina. Cross-sectional survey data examined for 221 cross sections from 26 sites showed that channel adjustments were highly variable from site to site, but approximately 60 % of the sites underwent at least a 20 % net change in channel capacity. Evaluation of in-stream structures ranging from 1 to 8 years in age showed that about half of the structures were impaired at 10 of the 26 sites. Major structural damage was often associated with floods of low to moderate frequency and magnitude. Failure mechanisms varied between sites and structure types, but included: (1) erosion of the channel bed and banks (outflanking); (2) movement of rock materials during floods; and (3) burial of the structures in the channel bed. Sites with reconstructed channels that exhibited large changes in channel capacity possessed the highest rates of structural impairment, suggesting that channel adjustments between structures led to their degradation of function. The data question whether currently used in-stream structures are capable of stabilizing reconfigured channels for even short periods when applied to dynamic rivers.

Retention of canopy trees as biological legacies for balancing woody biomass production and biodiversity in managed aspen forests of the Great Lakes Region

Green-tree retention under the conceptual framework of ecological forestry has the potential to provide both biomass feedstock for industry and maintain quality wildlife habitat. I examined the effects of retained canopy trees as biological legacies (“legacy trees”) in aspen (Populus spp.) forests on above-ground live woody biomass, understory plant floristic quality, and bird diversity. Additionally, I evaluated habitat quality for a high conservation priority species, the Golden-winged Warbler (Vermivora chrysoptera). I selected 27 aspen-dominated forest stands in northern Wisconsin with nine stands in each of three legacy tree retention treatments (conifer retention, hardwood retention, and clearcuts or no retention) across a chronosequence (4-36 years post-harvest). Conifer retention stands had greater legacy tree and all tree species biomass but lower regenerating tree biomass than clearcuts. Coniferous but not hardwood legacy trees appeared to suppress regenerating tree biomass. I evaluated the floristic quality of the understory plant assemblage by estimating the mean coefficient of conservatism (C). Mean C was lower in young stands than in middle-age or old stands; there was a marginally significant (p=0.058) interaction effect between legacy tree retention treatment and stand age. Late-seral plant species were positively associated with stand age and legacy tree diameter or age revealing an important relationship between legacy tree retention and stand development. Bird species richness was greatest in stands with hardwood retention particularly early in stand development. Six conservation priority bird species were indicators of legacy tree retention or clearcuts. Retention of legacy trees in aspen stands provided higher quality nest habitat for the Golden-winged Warbler than clearcuts based on high pairing success and nesting activity. Retention of hardwoods, particularly northern red oak (Quercus rubra), yielded the most consistent positive effects in this study with the highest bird species richness and the highest quality habitat for the Golden-winged Warbler. This treatment maintained stand biomass comparable to clearcuts and did not suppress regenerating tree biomass. In conclusion, legacy tree retention can enhance even-aged management techniques to produce a win-win scenario for the conservation of declining bird species and late-seral understory plants and for production of woody biomass feedstock from naturally regenerating aspen forests.

Geospatial analysis of western juniper (Juniperus occidentalis) encroachment utilizing remotely sensed data

Utilizing remote sensing methods to assess landscape-scale ecological change are rapidly becoming a dominant force in the natural sciences. Powerful and robust non-parametric statistical methods are also actively being developed to compliment the unique characteristics of remotely sensed data. The focus of this research is to utilize these powerful, robust remote sensing and statistical approaches to shed light on woody plant encroachment into native grasslands--a troubling ecological phenomenon occurring throughout the world. Specifically, this research investigates western juniper encroachment within the sage-steppe ecosystem of the western USA. Western juniper trees are native to the intermountain west and are ecologically important by means of providing structural diversity and habitat for many species. However, after nearly 150 years of post-European settlement changes to this threatened ecosystem, natural ecological processes such as fire regimes no longer limit the range of western juniper to rocky refugia and other areas protected from short fire return intervals that are historically common to the region. Consequently, sage-steppe communities with high juniper densities exhibit negative impacts, such as reduced structural diversity, degraded wildlife habitat and ultimately the loss of biodiversity. Much of today's sage-steppe ecosystem is transitioning to juniper woodlands. Additionally, the majority of western juniper woodlands have not reached their full potential in both range and density. The first section of this research investigates the biophysical drivers responsible for juniper expansion patterns observed in the sage-steppe ecosystem. The second section is a comprehensive accuracy assessment of classification methods used to identify juniper tree cover from multispectral 1 m spatial resolution aerial imagery.