An evaluation of GIS-derived landscape diversity units to guide landscape-level mapping of natural communities

As conservation planning increases in scale from specific sites to entire regions, organisations like The Nature Conservancy face a critical need for GIS-based tools to evaluate landscapes on a regional scale. An existing, field-based approach to analyse the diversity of a landscape is by delineating natural community types, which is a time-intensive process. This study evaluated the utility of using an existing, GIS-derived landscape diversity model as a predictive tool for mapping natural communities on a large (8369 ha) upland forest site in the northern Taconic region of Vermont. The GIS model incorporates four geophysical factors: elevation, bedrock type, surficial deposits, and landform. A significant level (α=0.05) of association between eight pairs of landscape diversity unit (LDU) types and natural community types was found. However, the strength of these associations is low (Cramer's V values 0.172), suggesting a poor predictive efficiency of landscape diversity units for natural community types. The results suggest that variables in the LDU model are relevant to natural community distribution, but the LDU model alone is not an effective tool to aid in mapping of natural community types of upland forests in Vermont. Until better landscape-level techniques are developed, the role of this type of model is limited to screening the landscape for areas with a particular set of geophysical characteristics, which can help an ecologist interpret the patterns on the landscape, but cannot substitute for a field-based approach to natural community mapping.     

Biological soil crust salvage for dryland restoration: an opportunity for natural resource restoration

Biocrusts' functional importance and vulnerability to disturbance have motivated consistent interest in biocrust restoration, as well as a recent increase in research to cultivate biocrusts in laboratory and greenhouse settings for use in ecological restoration. As part of a sustainable approach to developing biocrust restoration, we argue that a complementary step is to improve and accelerate methods for salvaging biocrusts that would otherwise be destroyed in a forthcoming disturbance. The increasing rate and scale of disturbance pressures in drylands where biocrusts flourish means that the supply of salvageable biocrust and demand for that material in restoration greatly exceed the present cultivable supply. In this article we describe the state of knowledge for biocrust salvage, present a simple set of steps for conducting a salvage harvest, discuss risks and benefits when considering using salvage, and suggest future research directions to facilitate scaling up biocrust restoration using salvaged material. A focus on the use of salvaged biocrust as a restoration source may prove an important step to improve ecological restoration in notoriously difficult to restore dryland ecosystems.     

Bycatch: from emotion to effective natural resource management

Although bycatch has been an acknowledged component of fishery management for many years, its explosive growth as a major management issue has occurred over the past decade. Emergence of the bycatch issue can be traced to increasing world competition for the ocean's fishery resources and the rapid rise of the conservation and environmental movement in recent years. Bycatch has in the past several years been equated to waste, non-selective fishing methods that threaten non-target species and degradation of ocean ecosystems. Although some important steps have been taken to abate bycatch, frequently the problem is not perceived as a component of fishery management, e.g. establishing bycatch mortality rates and evaluating their consequences upon affected populations. Fishery scientists often estimate levels of bycatch, but the overall consequences of discard mortality resulting from the complex of fisheries operating in a region are frequently unknown and speculative. The sum of fishery-induced mortalities occurring as a result of harvesting often involves a significant number of fish in addition to catch and discard. An ICES study group has characterized fishing mortality as the aggregate of all catch mortalities including discard, illegal fishing and misreporting. It is unlikely that managers will, in the near future, have a full accounting of unobserved fishing mortality. Progress toward identifying and measuring such mortalities is receiving increasing attention.The authors suggest and provide an example of a matrix-type analysis for recording bycatch and other fishing mortalities. The matrix presentation would allow managers to evaluate various fishery-related mortality factors and their importance in developing management strategies.     

Phenology research for natural resource management in the United States

Natural resource professionals in the United States recognize that climate-induced changes in phenology can substantially affect resource management. This is reflected in national climate change response plans recently released by major resource agencies. However, managers on-the-ground are often unclear about how to use phenological information to inform their management practices. Until recently, this was at least partially due to the lack of broad-based, standardized phenology data collection across taxa and geographic regions. Such efforts are now underway, albeit in very early stages. Nonetheless, a major hurdle still exists: phenology-linked climate change research has focused more on describing broad ecological changes rather than making direct connections to local to regional management concerns. To help researchers better design relevant research for use in conservation and management decision-making processes, we describe phenology-related research topics that facilitate “actionable” science. Examples include research on evolution and phenotypic plasticity related to vulnerability, the demographic consequences of trophic mismatch, the role of invasive species, and building robust ecological forecast models. Such efforts will increase phenology literacy among on-the-ground resource managers and provide information relevant for short- and long-term decision-making, particularly as related to climate response planning and implementing climate-informed monitoring in the context of adaptive management. In sum, we argue that phenological information is a crucial component of the resource management toolbox that facilitates identification and evaluation of strategies that will reduce the vulnerability of natural systems to climate change. Management-savvy researchers can play an important role in reaching this goal.     

Using integrated state-of-environment reporting as a planning tool for resource management

The success of an ecosystems approach to river basin management depends greatly on the integration ofa wide range of information concerning the various components of the ecosystem, the formulation of realisticsolutions to complex problems, and finally, the support of all interested parties throughout the implementation phase:integrated State-of-Environment Reporting (SOER) can be an effective tool for meeting these challenges. Theecosystems approach is critical to the St. Lawrence Action Plan, a Canadian program which focuses on the protectionand conservation of the St. Lawrence River. The St. Lawrence Centre of Environment Canada not only acts asa catalyst in developing environmental partnerships among segments of the population, but synthesizes the resultsof these collective efforts. Its detailed evaluations on the state of the river environment perhaps best illustrate thenature of this task, because these reports must meet the particular environmental informational needs of many targetaudiences, which range from the general public to corporate decision-makers. SOER's practical nature facilitatesthe collection of data and the establishment of analysis targets and SOE indicators used in environmental monitoring.The integrated SOER framework developed at the St. Lawrence Centre represents a major challenge in the collection,integration, dissemination and use of environmental information. This framework is based in three majorobjectives: (1) information and education; (2) trend analysis and prediction; and (3) influence. Integrated SOER canbe a powerful tool: decision-makers will find it useful for designing action plans, while the general public can useit for assessing the state of the environment and the success of water management plans. Lastly, integrated SOERis also central to increasing public participation in the management of the environment, a factor essential to thesuccessful application of the ecosystems approach to water management.     

Climate change,uncertainty, and natural resource management

Climate change and its associated uncertainties are of concern to natural resource managers. Although aspects of climate change may be novel (e.g., system change and nonstationarity), natural resource managers have long dealt with uncertainties and have developed corresponding approaches to decision-making. Adaptive resource management is an application of structured decision-making for recurrent decision problems with uncertainty, focusing on management objectives, and the reduction of uncertainty over time. We identified 4 types of uncertainty that characterize problems in natural resource management. We examined ways in which climate change is expected to exacerbate these uncertainties, as well as potential approaches to dealing with them. As a case study, we examined North American waterfowl harvest management and considered problems anticipated to result from climate change and potential solutions. Despite challenges expected to accompany the use of adaptive resource management to address problems associated with climate change, we conclude that adaptive resource management approaches will be the methods of choice for managers trying to deal with the uncertainties of climate change. © 2010 The Wildlife Society.     

Exploring natural selection to guide breeding for agriculture

Climate change threatens reduced crop production and poses major challenges to food security. The breeding of climate‐resilient crop varieties is increasingly urgent. Wild plant populations evolve to cope with changes in their environment due to the forces of natural selection. This adaptation may be followed over time in populations at the same site or explored by examining differences between populations growing in different environments or across an environmental gradient. Survival in the wild has important differences to the objective of agriculture to maximize crop yields. However, understanding the nature of adaptation in wild populations at the whole genome level may suggest strategies for crop breeding to deliver agricultural production with more resilience to climate variability.     

Potential natural vegetation: validity and applicability in landscape planning and nature conservation

Abstract. Since the introduction of ‘potential natural vegetation’ (PNV) as a concept in vegetation science by Tüxen (1956), many PNV-maps with different scales have been made. Tüxen emphasized the great value of PNV-maps for different purposes in land use, landscape planning and nature conservation, in particular with regard to forestry, agriculture and landscape management. Different aspects are discussed in order to examine the validity and applicability of PNV-maps in landscape planning and nature conservation. PNV-maps are useful for the differentiation of natural and landscape units on a small scale (< 1 : 100 000). However, maps of the potential natural vegetation are less useful for purposes of detailed planning on larger scales (> 1 : 100 000). Problems arise, for example, from the often highly hypothetical character of the construction and the practice of taking remnants of ‘natural’ vegetation as a reference object for the PNV. With regard to the goals of modern landscape planning and nature conservation purposes (e.g. conserving biodiversity in the cultural landscape of Central Europe) the exact documentation of the actual real vegetation (ARV) on intermediate and large scales gives much more detailed information than a hypothetical PNV.     

Special issue: Local landscape planning and management in rural areas

Landscape and Ecological Engineering -     

Estimating realistic costs for strategic management planning of invasive species eradications on islands

Environmental managers regularly face decisions about how to counteract threats. These decisions require an understanding of both the conservation benefits and economic costs of candidate actions. However, transparent frameworks for how to accurately calculate costs for management are rare. We worked with island managers in Australia to develop eradication protocols for six invasive species- four mammals and two weeds. We used the protocols to create an accounting framework for invasive species eradications to produce realistic cost estimates for eradications across multiple locations. We also used our models to test common cost assumptions: (1) that costs scale linearly with area, (2) that terrain does not influence costs, and (3) that eradication costs stay constant through time. By explicating testing assumptions, we found that costs largely scaled linearly with area, that terrain influences costs, and that costs decline as populations decline in response to ongoing management. Estimated mammal eradication costs were driven in large part by the area of an island and the cost of transport. However, when area alone was used as a proxy for costs, the calculated costs deviated from our modelled costs by 40–56%. Weed eradication cost estimates were driven by the size and density of an infestation as well as the terrain of the island, with the effect of terrain becoming more pronounced as area to be treated increased. We provide a method to calculate realistic costs across several sites, which can be used to guide strategic management decision-making, including prioritisation, and on-ground management actions.     

A high resolution broad scale spatial indicator of grain growing profitability for natural resource planning

The balancing of sustainable agricultural production with environmental, social, cultural and community objectives has become an increasing priority worldwide. Political focus has been on the prevention of environmental degradation and improving biodiversity values under the uncertainty of the impacts of climate change on rural livelihoods. In Australia, dry land salinisation is a major cause of environmental degradation in grain growing regions: at a farm scale the adoptions of key environmental strategies, such as revegetation, need to be considered.This study proposes that the identification and quantification of the spatial variability of wheat grain yield within the cropping landscape may help guide this revegetation. We used precision agriculture technology to collect data at the sub-field scale in conjunction with satellite imagery at the regional scale to create a high resolution regional indicator of wheat yield. This indicator is used to identify the economic value of land at sub-field scale which then allows identification of areas of marginal cropping value. This information provides an indication of how much land can be devoted to revegetation and quantifies the economic trade-off needed for this substitution to take place.Results of this study demonstrate that 90% of the income generated within the area of interest was produced by 55–74% of the wheat growing area depending on the choice of cost price scenarios. Between 27% and 44% of the study area made a financial loss or marginal monetary return indicating that trade-offs providing increased environmental benefits may be possible with minimal income loss from a substantial magnitude of cropping area. Although further analysis at larger regions with longer time series is necessary, results presented here show that overall economic returns may be improved by the reassignment of land use in selected cropping areas.The study also suggests that feasibility analyses of land use change at farm and regional scales should be conducted with a spatial resolution that is fine enough to reflect the spatial variability observed from yield mapping. While this information will not be available on every farm, this study shows that it may be possible to predict yield variability from remotely sensed imagery, thus providing a means to circumvent this problem and to produce high resolution indicators at a regional extent.     

An expert-based landscape permeability model for assessing the impact of agricultural management on amphibian migration

The persistence of pond-breeding amphibian populations is influenced on different spatial scales ranging from the individual breeding pond to surrounding habitat patches to landscape clusters of breeding pond populations. The connectivity among breeding ponds as well as the availability of suitable terrestrial habitats surrounding the ponds plays a major role in long-term viability of amphibian species. Besides road traffic and urban structures agricultural land activity can disrupt landscape connectivity through the use of pesticides, fertilizers and physical activity such as tillage. We developed an expert-based model to assess the impact of agricultural management measures on the migration area and terrestrial habitat availability for seven amphibian species. The model is based on a Habitat Suitability Index to identify suitable terrestrial habitats and includes a landscape permeability approach. Size of migration areas, connectivity of breeding ponds and number of reachable terrestrial habitats were modeled considering species-specific migration ranges and habitat preferences. We consider how pesticides application might lead to fragmentation and isolation of amphibian breeding pond populations. Therefore the potential disrupting impact of pesticides was simulated by inflating landscape resistance to medium and high migration cost. One amphibian species showed a decrease of migration area by 48.3% and a decrease of reachable terrestrial habitats by 41.5% at high migration costs. Three additional species showed a decrease of their migration areas between 31.5 and 35.7%. At increased migration cost, some of the investigated populations were isolated at breeding pond level or restricted to pond clusters. Our model could be used to prioritize conservation efforts for pond-breeding amphibians with adequate consideration of agricultural land use and its impact on amphibian migration.     

Distribution of plant functional types along gradients of disturbance intensity and resource supply in an agricultural landscape

Abstract. In this study, plant functional types are understood as groups of plants with similar biological traits displaying significant optima or maxima on a gradient plane of resource supply and disturbance intensity. The biological traits refer to expansion, vegetative regeneration, generative reproduction, dispersal and seed bank longevity. 129 vegetation samples were taken in an agricultural landscape in southwestern Germany, covering a wide range of terrestrial vegetation types – but with the exception of forests and wetlands. For each site, also soil data were recorded. Mean daily soil moisture was estimated with a simple model. Soil moisture, balanced nitrogen supply and available phosphorus were combined into a factor ‘resource supply’. In addition, disturbance intensity was estimated for each site. This factor was based on (1) frequency of disturbance, (2) disturbance depth below or above the soil surface, and (3) proportion of the area affected by a discrete disturbance event. 30 plant groups with similar biological characteristics resulted from a cluster analysis, based on a compilation of 19 biological traits for a regional species pool. Logistic regression on a gradient plane of disturbance intensity and resource supply yielded response curves for 28 groups. The dependent variable was defined as the probability of encountering all members of a group in a sample. 17 groups display a significant response curve on the gradient plane. Plants with a potential for long- range dispersal are concentrated on sites with low or high disturbance intensities (e.g. fallow land, fields, lawns). On sites with medium disturbance intensity (e.g. meadows) and low to medium resource supply, small-range dispersal predominates. There are no distinct trends concerning seed bank longevity. The potential for vertical and lateral expansion increases with decreasing disturbance intensity. Only at medium disturbance intensities does vertical expansion correlate positively with resource supply. Rapid detachment of daughter individuals occurs more often on productive sites than on less productive sites. Diversity of groups with similar biological traits is highest on sites with medium disturbance intensities.     

Modelling marine community responses to climate‐driven species redistribution to guide monitoring and adaptive ecosystem‐based management

As a consequence of global climate‐driven changes, marine ecosystems are experiencing polewards redistributions of species – or range shifts – across taxa and throughout latitudes worldwide. Research on these range shifts largely focuses on understanding and predicting changes in the distribution of individual species. The ecological effects of marine range shifts on ecosystem structure and functioning, as well as human coastal communities, can be large, yet remain difficult to anticipate and manage. Here, we use qualitative modelling of system feedback to understand the cumulative impacts of multiple species shifts in south‐eastern Australia, a global hotspot for ocean warming. We identify range‐shifting species that can induce trophic cascades and affect ecosystem dynamics and productivity, and evaluate the potential effectiveness of alternative management interventions to mitigate these impacts. Our results suggest that the negative ecological impacts of multiple simultaneous range shifts generally add up. Thus, implementing whole‐of‐ecosystem management strategies and regular monitoring of range‐shifting species of ecological concern are necessary to effectively intervene against undesirable consequences of marine range shifts at the regional scale. Our study illustrates how modelling system feedback with only limited qualitative information about ecosystem structure and range‐shifting species can predict ecological consequences of multiple co‐occurring range shifts, guide ecosystem‐based adaptation to climate change and help prioritise future research and monitoring.     

Optimum timing for integrated pest management: Modelling rates of pesticide application and natural enemy releases

Many factors including pest natural enemy ratios, starting densities, timings of natural enemy releases, dosages and timings of insecticide applications and instantaneous killing rates of pesticides on both pests and natural enemies can affect the success of IPM control programmes. To address how such factors influence successful pest control, hybrid impulsive pest-natural enemy models with different frequencies of pesticide sprays and natural enemy releases were proposed and analyzed. With releasing both more or less frequent than the sprays, a stability threshold condition for a pest eradication periodic solution is provided. Moreover, the effects of times of spraying pesticides (or releasing natural enemies) and control tactics on the threshold condition were investigated with regard to the extent of depression or resurgence resulting from pulses of pesticide applications. Multiple attractors from which the pest population oscillates with different amplitudes can coexist for a wide range of parameters and the switch-like transitions among these attractors showed that varying dosages and frequencies of insecticide applications and the numbers of natural enemies released are crucial. To see how the pesticide applications could be reduced, we developed a model involving periodic releases of natural enemies with chemical control applied only when the densities of the pest reached the given Economic Threshold. The results indicate that the pest outbreak period or frequency largely depends on the initial densities and the control tactics.