Lichen Conservation in Heavily Managed Boreal Forests

Lichens are an important component of the boreal forest, where they are long lived, tend to accumulate in older stands, and are a major food source for the threatened woodland caribou (Rangifer tarandus caribou). To be fully sustainable, silvicultural practices in the boreal forest must include the conservation of ecological integrity. Dominant forest management practices, however, have short‐term negative effects on lichen diversity, particularly the application of herbicides. To better understand the long‐term effects of forest management, we examined lichen regeneration in 35 mixed black spruce (Picea mariana) and jack pine (Pinus banksiana) forest stands across northern Ontario to determine recovery following logging and postharvest silvicultural practices. Our forest stands were 25–40 years old and had undergone 3 common sivilcultural treatments that included harvested and planted; harvested, planted, and treated with N‐[phosphonomethyl] glycine (glyphosate); and harvested, planted, and treated with 2,4‐dichlorophenoxyacetic acid (2,4‐D). Forest stands with herbicide treatments had lower lichen biomass and higher beta and gamma diversity than planted stands that were not treated chemically or control stands. In northwestern Ontario, planted stands that were not treated chemically had significantly greater (p < 0.05) alpha diversity than stands treated with herbicides or control stands. Our results show that common silvicultural practices do not emulate natural disturbances caused by wildfires in the boreal forest for the lichen community. We suggest a reduction in the amount of chemical application be considered in areas where lichen biomass is likely to be high and where the recovery of woodland caribou is an objective. Conservación de Líquenes en Bosques Boreales Manejados Intensivamente     

Defining the Impact of Non‐Native Species

Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts. Definiendo el Impacto de las Especies No‐Nativas     

Impact of Forestry Practices on Fitness Correlates and Population Productivity in an Open-Nesting Bird Species

Abstract:  In the boreal forests of Fennoscandia, over 99% of forest area has been altered by forestry practices, which has created forest with age structures and stand characteristics that differ from primary forest stands. Although many researchers have investigated how forestry affects species abundance, few have assessed how forestry practices affect fitness correlates of species living in altered habitats, and this has negatively affected management efforts. We experimentally addressed the effect of standard forestry practices on fitness correlates of an open-nesting, long-lived bird species typical to boreal forests of Eurasia, the Siberian Jay ( Perisoreus infaustus ). We used a before-after comparison of reproductive data on the level of territories and found that standard forestry practices had a strong negative effect on the breeding success of jays. Both partial thinning of territories and partial clearcutting of territories reduced future breeding success by a factor of 0.35. Forestry practices reduced territory occupancy. Thus, over the 15 years of the study, productivity of the affected population declined over 50% as a result of territory abandonment and reduced breeding success. Results of previous studies on Siberian Jays suggest that the strong effect of forest thinning on fitness is explained by the fact that most common predators of nests and adults are visually oriented and thus thinning makes prey and nests more visible to predators. The consequences of thinning we observed are likely to apply to a wide range of species that rely on understory to provide visual protection from predators. Thus, our results are important for the development of effective conservation management protocols and for the refinement of thinning practices.     

Managing Water Quality in Developing Countries

Over the next decade the management of water quality will be one of the outstanding issues relating to the protection and conservation of the national stock of water. In the past, particularly in countries well-endowed with water resources, this has been considered to be a relatively negligible problem. However, the rapid growth of population in major urban centres, industrialization and the heavy dependence on chemical products in the agricultural sector are leading to a serious deterioration of water quality.
This paper reviews the nature of the pollution issue, the institutional requirements to deal with the problem in an effective and comprehensive manner and the near-term actions which governments should take to protect their existing water resources.     

The Interior-to-Edge Breakpoint Distance as a Guideline for Nature Conservation Policy

A method is proposed to quantify disturbance impact on isolated habitats. For every landscape patch, the breakpoint distance, defined as the penetration distance for which equality of interior and edge habitat is observed, can be calculated. Disturbance with equal impact at all patch sides is assumed. Effects of patch compactness, size, convolution, and perforation are discussed. The potential use of the measure for nature reserve design is discussed. The breakpoint distance follows the reserve design guidelines for individual patches, based on island biogeography and is consistent with the form and function principle. A large breakpoint distance is preferred for natural habitats. Small size, small compactness, intense convolution, and the occurrence of many gaps depress the breakpoint distance.     

Long-Term Effect of Instream Habitat-Improvement Structures on Channel Morphology Along the Blackledge and Salmon Rivers, Connecticut, USA

Habitat-improvement structures on the Blackledge and Salmon rivers date back to the 1930s and 1950s. Forty of these structures were investigated to determine their long-term impact on channel morphology. These structures include designs that continue to be used in modern restoration efforts. During the intervening period since these structures were introduced, several major floods have affected the two channels. The floods include three flows in excess of the 50-year event, including the flood of record, which has an estimated recurrence interval of almost 300 years. Despite the extreme flooding, many structures were discovered in varying conditions of operation. Grade-control structures and low-flow deflectors generally create some low-flow habitat (P = 0.815) but do not produce the depth of water predicted by design manuals (P < 0.0001). Unintended erosion has developed in response to many of the channel modifications especially along the outside of meanders. In addition, the mode of failure of grade-control structures has created localized channel widening with associated bank erosion. Meanwhile, cover structures have produced a 30% reduction in streamside vegetation with over 75% less overhead cover than unaltered reaches. Based on these results, it is important for prospective designers to carefully consider the long-term impacts of instream structures when developing future channel-restoration projects.     

Conservation Benefits of Temperate Marine Protected Areas: Variation among Fish Species

Abstract:  Marine protected areas, and other fishery management systems that impart partial or total protection from fishing, are increasingly advocated as an essential management tool to ensure the sustainable use of marine resources. Beneficial effects for fish species are well documented for tropical and reef systems, but the effects of marine protected areas remain largely untested in temperate waters. We compared trends in sport-fishing catches of nine fish species in an area influenced by a large (500-km²) towed-fishing-gear restriction zone and in adjacent areas under conventional fishery management controls. Over the period 1973–2002 the mean reported weight of above-average-sized (trophy) fish of species with early age at maturity and limited home range was greatest within the area influenced by the fishing-gear restriction zone. The reported weight of trophy fish of species that mature early also declined less and more slowly over time within the area influenced by the fishing-gear restriction zone. Importantly, the mean reported weight of trophy fish of species that mature late and those that undertake extensive spatial movements declined at the same rate in all areas. Hence these species are likely to require protected areas >500 km² for effective protection. Our results also indicated that fish species with a localized distribution or high site fidelity may require additional protection from sport fishing to prevent declines in the number or size of fish within the local population.     

Postfire Seeding for Erosion Control: Effectiveness and Impacts on Native Plant Communities

Abstract:  Large, high-severity wildfires remove vegetation cover and expose mineral soil, ofen causing erosion and runoff during postfire rain events to increase dramatically. Land-management agencies in the United States are required to assess site conditions after wildfire and, where necessary, implement emergency watershed rehabilitation measures to help stabilize soil; control movement of water, sediment, and debris; prevent permanent impairment of ecosystem structure and function; and mitigate significant threats to human health, safety, life, property, or downstream values. One of the most common postfire treatments is broadcast seeding of grasses, usually from aircraft. Non-native annual or perennial grasses typically are used to provide quick, temporary ground cover to hold soil in place until native plants are reestablished. Critics argue that seeded grasses compete with native vegetation and do not effectively reduce erosion. Few data exist on the effectiveness of erosion control; less than half of the studies I reviewed showed reduced sediment movement with seeding. In all vegetation types, successful growth of seeded grasses—enough to affect erosion—appears to displace native or naturalized species, including shrub and tree seedlings. Due to the competitiveness of seeded grasses, they are used to attempt suppression of noxious weeds in some postfire seeding operations. In burned sagebrush range, postfire seeding is frequently used to replace non-native cheatgrass (  Bromus tectorum ) with native or introduced bunchgrasses, with at least short-term success. In recent years, native species and sterile cereal grains have increasingly been used for seeding. Use of aerially applied straw mulch has increased as well, with the risk of weed introduction from contaminated bales. More research on the effectiveness and ecosystem impacts of these alternatives is needed.     

Testing Decision Rules for Categorizing Species’ Extinction Risk to Help Develop Quantitative Listing Criteria for the U.S. Endangered Species Act

Lack of guidance for interpreting the definitions of endangered and threatened in the U.S. Endangered Species Act (ESA) has resulted in case‐by‐case decision making leaving the process vulnerable to being considered arbitrary or capricious. Adopting quantitative decision rules would remedy this but requires the agency to specify the relative urgency concerning extinction events over time, cutoff risk values corresponding to different levels of protection, and the importance given to different types of listing errors. We tested the performance of 3 sets of decision rules that use alternative functions for weighting the relative urgency of future extinction events: a threshold rule set, which uses a decision rule of x% probability of extinction over y years; a concave rule set, where the relative importance of future extinction events declines exponentially over time; and a shoulder rule set that uses a sigmoid shape function, where relative importance declines slowly at first and then more rapidly. We obtained decision cutoffs by interviewing several biologists and then emulated the listing process with simulations that covered a range of extinction risks typical of ESA listing decisions. We evaluated performance of the decision rules under different data quantities and qualities on the basis of the relative importance of misclassification errors. Although there was little difference between the performance of alternative decision rules for correct listings, the distribution of misclassifications differed depending on the function used. Misclassifications for the threshold and concave listing criteria resulted in more overprotection errors, particularly as uncertainty increased, whereas errors for the shoulder listing criteria were more symmetrical. We developed and tested the framework for quantitative decision rules for listing species under the U.S. ESA. If policy values can be agreed on, use of this framework would improve the implementation of the ESA by increasing transparency and consistency. Evaluando Reglas de Decisión para Categorizar el Riesgo de Extinción de Especies con el Fin de Desarrollar de Criterios Cuantitativos de Alistamiento en el Acta de Especies en Peligro de los EE. UU.     

Legitimizing Fluvial Ecosystems as Users of Water: An Overview

We suggest that fluvial ecosystems are legitimate users of water and that there are basic ecological principles guiding the maintenance of long-term ecological vitality. This article articulates some fundamental relationships between physical and ecological processes, presents basic principles for maintaining the vitality of fluvial ecosystems, identifies several major scientific challenges and opportunities for effective implementation of the basic ecological principles, and acts as an introduction to three specific articles to follow on biodiversity, biogeochemistry, and riparian communities. All the objectives, by necessity, link climate, land, and fresh water. The basic principles proposed are: (1) the natural flow regime shapes the evolution of aquatic biota and ecological processes, (2) every river has a characteristic flow regime and an associated biotic community, and (3) aquatic ecosystems are topographically unique in occupying the lowest position in the landscape, thereby integrating catchment-scale processes. Scientific challenges for the immediate future relate to quantifying cumulative effects, linking multidisciplinary knowledge and models, and formulating effective monitoring and assessment procedures. Additionally, forecasting the ecological consequences of changing water regimes is a fundamental challenge for science, especially as environmental issues related to fresh waters escalate in the next two to three decades.