Current Monitoring Efforts Research Articles

Indicators for biodiversity and ecosystem services: towards an improved framework for ecosystems assessment

Ecosystem assessment and monitoring requires the development and application of suitable indicators, i.e. they need to be (i) reliable and capable of simplifying complex relationships, (ii) quantifiable and transparent in order to enable an easy communication, and (iii) fit for the purpose of indication. These requirements are scarcely fulfilled in current ecosystem assessment and monitoring efforts to address the requirements of international biodiversity conventions. Here we present and test a set of seven criteria towards an improved framework for ecosystems indication with particular emphasis on the indication of biodiversity and ecosystem services: purpose of indication, indicator type according to the EEA’s Driver-Pressure-State-Impact-Response scheme, direct/indirect linkages to biodiversity and ecosystem services, spatial scale and scalability across scales, applicability of benchmarks/reference values, availability of data and protocols, and applicability of remote sensing. The criteria are tested using 24 indicators of ecosystem assessment and monitoring at the global, continental and regional scale. Based on the general trends revealed by our evaluation, we present recommendations to streamline and improve ecosystem indication with respect to international biodiversity conventions. The implementation of our recommendations does require concerted international effort, comparable, for instance, to the implementation of the Water Framework Directive in Europe.

Anticoagulant Residues in Non-Target Wildlife – Assessing Sublethal Exposure to Brodifacoum without Lethal Sampling

Author(s): Fisher, Penny; Shlosberg, Alan; Brown, Leslie; Wright, Geoff | Abstract: Residues of brodifacoum and other second-generation anticoagulant rodenticides are reported worldwide in a range of non-target wildlife, especially predatory or scavenging birds and mammals. Determination of exposure to brodifacoum in such cases relies on analysis of liver tissue. This limits current monitoring efforts to either destructive sampling of live birds or mammals to obtain liver, but more commonly opportunistic post-mortem liver sampling from carcasses in suitable condition. Also, detection of brodifacoum in liver often cannot be confirmed as a contributor to mortality, and within a potential ‘sublethal’ concentration range the toxicological significance of its presence is uncertain. We sought to determine whether dried blood spot (DBS) sampling could form the basis of a non-lethal, minimally invasive method for determining sublethal exposure to brodifacoum in live birds. Validation of a method for detecting brodifacoum in DBS samples, and preliminary comparison of brodifacoum concentrations in DBS and plasma samples, are described.

Habitat reporting of a heathland site: Classification probabilities as additional information, a case study

Heathlands are man-made habitats and their decline during the last century can be contributed to shifts in both agricultural and management practices as well as to hydrological and atmospheric changes. As a result, many heathland sites, including the Kalmthoutse Heide in Belgium, were included in the European Natura 2000 program, a network of protected areas across the European Union. To assure an accurate mapping of the Kalmthoutse Heide and other Natura 2000 sites in Belgium a classification framework for habitat status reporting with remote sensing data and in particular high resolution hyperspectral imagery was started. In this study we propose a simple and fast context based method for mapping heathland heterogeneity using the intermediate, otherwise redundant, classification probabilities as generated by a hard classification algorithm. Our study proved to be successful in using intermediate classification probabilities as a valuable source of ecological information. The delineated areas have been shown to be statistically sound and robust compared to a neutral model. The technique is not limited to a particular hard classification technique and can easily be adopted into current vegetation monitoring efforts. The resulting maps provided accessible maps which can support management of the protected site and enhance the accuracy of EU reportage as required by the habitat directive.

Variation in abundance across a species' range predicts climate change responses in the range interior will exceed those at the edge: a case study with North American beaver

AbstractThe absence of information about how abundance varies across species' ranges restricts most modeling and monitoring of climate change responses to the range edge. We examine spatial variation in abundance across the northeastern range of North American beaver (Castor canadensis), evaluate the extent to which climate and nonclimate variables explain this variation, and use a species–climate envelope model that includes spatial variation in abundance to predict beaver abundance responses to projected climate change. The density of beaver colonies across Québec follows a roughly logistic pattern, with high but variable density across the southern portion of the province, a sharp decline in density at about 49°N, and a long tail of low density extending as far as 58°N. Several climate and nonclimate variables were strong predictors of variation in beaver density, but 97% of the variation explained by nonclimate variables could be accounted for by climate variables. Because of the peak and tail density pattern, beaver climate sensitivity (change in density per unit change in climate) was greatest in the interior and lowest at the edge of the range. Combining our best density–climate models with projections from general circulation models (GCM) predicts a relatively modest expansion of the species' northern range limit by 2055, but density increases in the range interior that far exceed those at the range edge. Thus, some of the most dramatic responses to climate change may be occurring in the core of species' ranges, far away from the edge‐of‐the‐range focus of most current modeling and monitoring efforts.

Forecasting the potential distribution of the invasive tunicate Didemnum vexillum

Summary Invasive species are a major threat to global biodiversity and their introduction can have significant economic consequences. The invasive tunicate Didemnum vexillum is a notorious invader with significant negative impacts on cultured shellfish and natural benthic communities, including commercially important ones. We conducted an expert survey, identifying the five most important transport vectors for D. vexillum along the west coast of North America. We determined the spatially explicit vector density for all vectors in order to identify introduction hotspots. Additionally, we developed an environmental niche model based on 46 occurrence points and nine environmental variables to identify areas suitable for D. vexillum. Spatial distribution of the most important transport vectors (slow‐moving vessels, aquaculture, fishing vessels, small vessels, and large commercial vessels) identified several hotspots with high vector densities. These proved to be a very good predictor of current D. vexillum occurrence in British Columbia (BC). Ecological niche modelling (Genetic Algorithm for Rule‐set Prediction) predicted suitable environments in southern BC, parts of central BC and along the east coast of the Queen Charlotte Islands. Independent validation of the model based on the current distribution in BC indicated good predictive accuracy. Additional analytical steps confirmed that no environmental variable dominated the predictions and we identified ranges of environmental conditions predicted suitable by the model. We identified areas of high establishment probability for D. vexillum by combining the vector model and environmental niche model. Parts of central BC, the west coast of Vancouver Island and the Strait of Georgia are areas where D. vexillum is most likely to establish. Synthesis and applications. Spatially explicit predictions of the potential distribution of biological invaders are crucial for informing risk assessments, development of management strategies, and resource allocation. While most studies only focus on one step in the invasion process, we successfully combined the likelihood of introduction and establishment. Results from this study are informing the canadian risk assessment of invasive tunicates, guiding current monitoring efforts, and providing a basis for potential intervention/mediation measures.

An Overview of Monitoring Options for Assessing the Response of Salmonids and Their Aquatic Ecosystems in the Elwha River Following Dam Removal

Removal of two hydroelectric dams on the Elwha River, Washington, one of the largest river restoration projects in the United States, represents a unique opportunity to assess the recovery of fish populations and aquatic ecosystems at the watershed scale. The current project implementation does not contain sufficient funding to support comprehensive monitoring of restoration effectiveness. As a result, current monitoring efforts are piecemeal and uncoordinated, creating the possibility that project managers will not be able to answer fundamental questions concerning salmonid and ecosystem response. We present the initial elements of a monitoring framework designed to assess the effectiveness of dam removal on the recovery of Elwha River salmonids, their aquatic habitats, and the food webs of which they are an integral component. The monitoring framework is linked to the Elwha Fisheries Restoration Plan, which outlines the restoration of native stocks of salmon and relies upon a process of adaptive management. The monitoring framework includes two areas of emphasis—salmonid population recovery and ecosystem response. We provide study design considerations and make recommendations for additional monitoring efforts prior to dam removal. Based on a power analysis, we determined that a minimum of 3–11 years and up to 50 years of monitoring will be required to capture potential ecosystem responses following dam removal. The development of a monitoring plan will be a significant step forward in objectively evaluating the success of Elwha River dam removal.

Ghost runs: management and status assessment of Pacific salmon (Oncorhynchus spp.) returning to British Columbia’s central and north coasts

The management of Pacific salmon ( Oncorhynchus spp.) populations, which are spatially distributed across thousands of waterways in coastal British Columbia, Canada, presents considerable challenges to resource managers. We evaluated the efficacy of salmon management by Fisheries and Oceans Canada (DFO) over the past 55 years in two key areas: (i) the achievement of internally generated target escapement levels and (ii) escapement monitoring. We show that less than 4% of monitored streams (n = 7 of 215), which represent a small fraction of all salmon-bearing waterways (n = 2592), have consistently met escapement targets since 1950. During this same period, the number of streams monitored by DFO has simultaneously decreased. Further, current monitoring efforts fall short of encompassing the range of salmon diversity identified within recently designated conservation units. Importantly, we found that this erosion of monitoring effort has been biased towards dropping smaller runs that failed to meet target escapements in the previous decade. We suggest that such increasingly selective monitoring is presenting a progressively more biased evaluation of population health. In addition to fostering a “shifting baseline” syndrome, we conclude that these changes to monitoring can not provide data required for precautionary harvest management under the high exploitation levels that these runs experience.

Variation in abundance across a species' range predicts climate change responses in the range interior will exceed those at the edge: a case study with North American beaver

The absence of information about how abundance varies across species' ranges restricts most modeling and monitoring of climate change responses to the range edge. We examine spatial variation in abundance across the northeastern range of North American beaver (Castor canadensis), evaluate the extent to which climate and nonclimate variables explain this variation, and use a species-climate envelope model that includes spatial variation in abundance to predict beaver abundance responses to projected climate change. The density of beaver colonies across Quebec follows a roughly logistic pattern, with high but variable density across the southern portion of the province, a sharp decline in density at about 491N, and a long tail of low density extending as far as 581N. Several climate and nonclimate variables were strong predictors of variation in beaver density, but 97% of the variation explained by nonclimate variables could be accounted for by climate variables. Because of the peak and tail density pattern, beaver climate sensitivity (change in density per unit change in climate) was greatest in the interior and lowest at the edge of the range. Combining our best density-climate models with projections from general circulation models (GCM) predicts a relatively modest expan- sion of the species' northern range limit by 2055, but density increases in the range interior that far exceed those at the range edge. Thus, some of the most dramatic responses to climate change may be occurring in the core of species' ranges, far away from the edge-of-the-range focus of most current modeling and monitoring efforts.

Using retrospective health data from the Gombe chimpanzee study to inform future monitoring efforts

Disease outbreaks, either in isolation or in concert with other risk factors, can pose serious threats to the long-term persistence of mammal populations, and these risks become elevated as population size decreases and/or population isolation increases. Many chimpanzee study sites are increasingly isolated by loss of habitat due to human encroachment, and managers of parks that contain chimpanzees perceive that disease outbreaks have been and continue to be significant causes of mortality for chimpanzees. Major epidemics at Gombe National Park include suspected polio in 1966; respiratory diseases in 1968, 1987, 1996, 2000, and 2002; and sarcoptic mange in 1997. These outbreaks have led park managers and researchers working in Gombe to conclude that disease poses a substantial risk to the long-term survival of Gombe's chimpanzee population. We surveyed behavioral data records spanning 44 years for health-related data and found a combination of standardized and nonstandardized data for the entire period. Here we present the types of data found during the survey, discuss the usefulness of these data in the context of risk assessment, and describe how our current monitoring effort at Gombe was designed based on our findings.

Estimating Numbers of Greater Prairie-Chickens Using Mark–Resight Techniques

Current monitoring efforts for greater prairie-chicken (Tympanuchus cupido pinnatus) populations indicate that populations are declining across their range. Monitoring the population status of greater prairie-chickens is based on traditional lek surveys (TLS) that provide an index without considering detectability. Estimators, such as immigration–emigration joint maximum-likelihood estimator from a hypergeometric distribution (IEJHE), can account for detectability and provide reliable population estimates based on resightings. We evaluated the use of mark–resight methods using radiotelemetry to estimate population size and density of greater prairie-chickens on 2 sites at a tallgrass prairie in the Flint Hills of Kansas, USA. We used average distances traveled from lek of capture to estimate density. Population estimates and confidence intervals at the 2 sites were 54 (CI 50–59) on 52.9 km2 and 87 (CI 82–94) on 73.6 km2. The TLS performed at the same sites resulted in population ranges of 7–34 and 36–63 and always produced a lower population index than the mark–resight population estimate with a larger range. Mark–resight simulations with varying male:female ratios of marks indicated that this ratio was important in designing a population study on prairie-chickens. Confidence intervals for estimates when no marks were placed on females at the 2 sites (CI 46–50, 76–84) did not overlap confidence intervals when 40% of marks were placed on females (CI 54–64, 91–109). Population estimates derived using this mark–resight technique were apparently more accurate than traditional methods and would be more effective in detecting changes in prairie-chicken populations. Our technique could improve prairie-chicken management by providing wildlife biologists and land managers with a tool to estimate the population size and trends of lekking bird species, such as greater prairie-chickens.

Monitoring and modeling horizontal gene transfer.

Monitoring efforts have failed to identify horizontal gene transfer (HGT) events occurring from transgenic plants into bacterial communities in soil or intestinal environments. The lack of such observations is frequently cited in biosafety literature and by regulatory risk assessment. Our analysis of the sensitivity of current monitoring efforts shows that studies to date have examined potential HGT events occurring in less than 2 g of sample material, when combined. Moreover, a population genetic model predicts that rare bacterial transformants acquiring transgenes require years of growth to out-compete wild-type bacteria. Time of sampling is there-fore crucial to the useful implementation of monitoring. A population genetic approach is advocated for elucidating the necessary sample sizes and times of sampling for monitoring HGT into large bacterial populations. Major changes in current monitoring approaches are needed, including explicit consideration of the population size of exposed bacteria, the bacterial generation time, the strength of selection acting on the transgene-carrying bacteria, and the sample size necessary to verify or falsify the HGT hypotheses tested.