Best Practicable Aggregation of Species: a step forward for species surrogacy in environmental assessment and monitoring

The available taxonomic expertise and knowledge of species is still inadequate to cope with the urgent need for cost‐effective methods to quantifying community response to natural and anthropogenic drivers of change. So far, the mainstream approach to overcome these impediments has focused on using higher taxa as surrogates for species. However, the use of such taxonomic surrogates often limits inferences about the causality of community patterns, which in turn is essential for effective environmental management strategies. Here, we propose an alternative approach to species surrogacy, the “Best Practicable Aggregation of Species” (BestAgg), in which surrogates exulate from fixed taxonomic schemes. The approach uses null models from random aggregations of species to minimizing the number of surrogates without causing significant losses of information on community patterns. Surrogate types are then selected in order to maximize ecological information. We applied the approach to real case studies on natural and human‐driven gradients from marine benthic communities. Outcomes from BestAgg were also compared with those obtained using classic taxonomic surrogates. Results showed that BestAgg surrogates are effective in detecting community changes. In contrast to classic taxonomic surrogates, BestAgg surrogates allow retaining significantly higher information on species‐level community patterns than what is expected to occur by chance and a potential time saving during sample processing up to 25% higher. Our findings showed that BestAgg surrogates from a pilot study could be used successfully in similar environmental investigations in the same area, or for subsequent long‐term monitoring programs. BestAgg is virtually applicable to any environmental context, allowing exploiting multiple surrogacy schemes beyond stagnant perspectives strictly relying on taxonomic relatedness among species. This prerogative is crucial to extend the concept of species surrogacy to ecological traits of species, thus leading to ecologically meaningful surrogates that, while cost effective in reflecting community patterns, may also contribute to unveil underlying processes. A specific R code for BestAgg is provided.     

Two roles for ecological surrogacy: Indicator surrogates and management surrogates

Ecological surrogacy – here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system – is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure “indicator surrogates” to provide information about ecological systems. Second, and often overlooked, are “management surrogates” (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as “maintain biodiversity” or “increase ecosystem resilience.” We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses.     

A test for assessment of saproxylic beetle biodiversity using subsets of “monitoring species”

In European forests, large scale biodiversity monitoring networks need to be implemented – networks which include components such as taxonomical groups that are at risk and that depend directly on forest stand structure. In this context, monitoring the species-rich group of saproxylic beetles is challenging. In the absence of sufficient resources to comprehensively survey a particular group, surrogates of species richness can be meaningful tools in biodiversity evaluations. In search of restricted subsets of species to use as surrogates of saproxylic beetle richness, we led a case study in Western Europe.Beetle data were compiled from 67 biodiversity surveys and ecological studies carried out from 1999 to 2010 with standardised trapping methods in France and Belgium. This large-scale dataset contains 642 forest plots, 1521 traps and 856 species. Twenty-two simplified species subsets were identified as potential surrogates, as well as the number of genera, a higher taxonomic level, taking into account, for each surrogate, the effort required for species identification, the practical monitoring experience necessary, the species conservation potential or the frequency of species occurrence. The performance of each surrogate was analyzed based on the following parameters: overall surrogacy (correlation between subset richness and total species richness), surrogacy vs. identification cost balance, surrogacy variation over a wide range of ecological conditions (forest type, altitude, latitude and bio-geographical area) and consistency with spatial scale. Ecological representativeness and ability to monitor rare species were supplementary criteria used to assess surrogate performance.The subsets consisting of the identifiable (or only easy-to-identify species) could easily be applied in practice and appear to be the best performing subsets, from a global point of view.The number of genera showed good prediction at the trap level and its surrogacy did not vary across wide environmental gradients. However, the subset of easy-to-identify species and the genus number were highly sensitive to spatial scale, which limits their use in large-scale studies. The number of rare species or the species richness of single beetle families (even the best single-family subset, the Cerambycidae) was very weak surrogates for total species richness. Conversely, the German list of monitoring species had high surrogacy, low identification costs and was not strongly influenced by the main geographical parameters, even with our French and Belgian data.In European-wide monitoring networks, such internationally validated subsets could be very useful with regard to the timing and cost-efficiency of field inventories.     

Spatial conservation priorities are highly sensitive to choice of biodiversity surrogates and species distribution model type

Pressure to conserve biodiversity with limited resources has led to increasing use of species distribution models (SDMs) for spatial conservation prioritization. Published spatial prioritization exercises often focus on well‐studied groups, with data compiled from on‐line databases of ad‐hoc collections. Conservation plans generally aim to protect all components of biodiversity, and it is implied that the species used in prioritization act as surrogates. Here, we assess the sensitivity of spatial priorities to model and surrogate choice using a case study from a fragmented agricultural area of south eastern Australia that is poorly represented in the national reserve system. We model the distributions of 30 species of bird, microbat and bee using two types of SDM; generalised linear models based on systematic surveys that yield presence and absence observations, and MaxEnt models based on biodiversity database records. Eight prioritization scenarios were tested using Zonation software, and were based on either the presence–background or presence–absence SDMs and combinations of surrogacy among the three taxa. We found low correlations between SDMs generated for the same species using different modelling frameworks (μ = 0.18, n = 26). Area under the receiver operating characteristic curve (AUC) estimates generated by MaxEnt were optimistic; on average 1.36 times higher than when tested against the systematic survey data. Conservation priorities were sensitive to the choice of surrogate and type of data used to fit SDMs, and though bats and birds formed moderately good surrogates for each other, there was less compelling evidence of surrogacy for bees. Because valid surrogacy is unlikely with most existing data sets, investment in high quality data for less‐surveyed groups prior to planning should still be a priority. If this is not possible, then it is advisable to analyse the sensitivity of conservation plans to the assumed surrogacy and quality of data available.     

Effectiveness of Biodiversity Surrogates for Conservation Planning: Different Measures of Effectiveness Generate a Kaleidoscope of Variation

Conservation planners represent many aspects of biodiversity by using surrogates with spatial distributions readily observed or quantified, but tests of their effectiveness have produced varied and conflicting results. We identified four factors likely to have a strong influence on the apparent effectiveness of surrogates: (1) the choice of surrogate; (2) differences among study regions, which might be large and unquantified (3) the test method, that is, how effectiveness is quantified, and (4) the test features that the surrogates are intended to represent. Analysis of an unusually rich dataset enabled us, for the first time, to disentangle these factors and to compare their individual and interacting influences. Using two data-rich regions, we estimated effectiveness using five alternative methods: two forms of incidental representation, two forms of species accumulation index and irreplaceability correlation, to assess the performance of ‘forest ecosystems’ and ‘environmental units’ as surrogates for six groups of threatened species—the test features—mammals, birds, reptiles, frogs, plants and all of these combined. Four methods tested the effectiveness of the surrogates by selecting areas for conservation of the surrogates then estimating how effective those areas were at representing test features. One method measured the spatial match between conservation priorities for surrogates and test features. For methods that selected conservation areas, we measured effectiveness using two analytical approaches: (1) when representation targets for the surrogates were achieved (incidental representation), or (2) progressively as areas were selected (species accumulation index). We estimated the spatial correlation of conservation priorities using an index known as summed irreplaceability. In general, the effectiveness of surrogates for our taxa (mostly threatened species) was low, although environmental units tended to be more effective than forest ecosystems. The surrogates were most effective for plants and mammals and least effective for frogs and reptiles. The five testing methods differed in their rankings of effectiveness of the two surrogates in relation to different groups of test features. There were differences between study areas in terms of the effectiveness of surrogates for different test feature groups. Overall, the effectiveness of the surrogates was sensitive to all four factors. This indicates the need for caution in generalizing surrogacy tests.     

Birds as surrogates for biodiversity: An analysis of a data set from southern Québec

Surrogacy analysis consists of determining a set of biotic or environmental parameters which can be rapidly assessed in the field and reliably used to prioritize places for biodiversity conservation. Whether adequate surrogate sets exist remains an open and relatively unexplored question though its solution is central to the aims of conservation biology. This paper analyses the surrogacy problem by prioritizing places using surrogate lists and comparing these results with those obtained by using more comprehensive species lists. More specifically, it explores (i) the possibility of using bird distributions, which are often easily available, as surrogates for species at risk (endangered and threatened species), which are presumed to be an important component of biodiversity; and (ii) the methodological question of how spatial scale influences surrogate success. The data set analysed, from southern Québec, is one of the most complete biotic data sets available at the regional scale. Contrary to some previous analyses, the results obtained suggest that the surrogacy problem is potentially solvable.     

Annelids, arthropods or molluscs are suitable as surrogate taxa for selecting conservation reserves in estuaries

The urgent need to conserve aquatic biodiversity and the lack of spatial data on biodiversity has motivated conservation planners and researchers to search for more readily obtainable information that could be used as proxies or surrogates. The surrogate taxon approach shows promise in some aquatic environments (e.g. intertidal) but not others (e.g. coral reefs, temperate rocky reefs). Estuaries are transitional environments at the land–sea junction with a unique biodiversity, but are the most threatened of aquatic environments because of high levels of human use. The comparatively small numbers of conservation reserves means that estuarine biodiversity is poorly protected. Selecting additional conservation reserves within estuaries would be facilitated by the identification of a suitable surrogate that could be used in conservation planning. In one estuary in Southeast Australia, we evaluated separately the effectiveness of annelids, arthropods, and molluscs as surrogates for predicting the species richness, abundance, assemblage variation, and summed irreplaceability of other species and for coincidentally representing other species in networks of conservation reserves selected for each surrogate. Spatial patterns in the species richness and assemblage variation (but not summed irreplaceability) of each surrogate were significantly correlated with the spatial patterns of other species. The total abundance of annelids and the total abundance of arthropods were each significantly correlated with the total abundances of other species. Networks of conservation reserves selected to represent each surrogate performed significantly better than random selection in representing other species. The greatest number of non-surrogate species was coincidentally included in reserves selected for the group of mollusc species. We conclude that annelids and arthropods are effective surrogate taxa for identifying spatial variation in several measures of conservation value (species richness, abundance, assemblage variation) in estuaries. We also conclude that spatial data on annelids, arthropods or molluscs can be used to select networks of conservation reserves in estuaries. The demonstrated effectiveness of these surrogates should facilitate future conservation planning within estuaries.     

Endemic vertebrates are the most effective surrogates for identifying conservation priorities among Brazilian ecoregions

Many studies have tested the performance of terrestrial vertebrates as surrogates for overall species diversity, because these are commonly used in priority‐setting conservation appraisals. Using a database of 3663 vertebrate species in 38 Brazilian ecoregions, we evaluated the effectiveness of various subsets for representing diversity of the entire vertebrate assemblage. Because ecoregions are established incorporating information on biotic assemblages, they are potentially more amenable to regional comparison than are national or state lists. We used 10 potential indicator groups (all species; all mammals, birds, reptiles, or amphibians; all endemic species; and endemic species within each class) to find priority sets of ecoregions that best represent the entire terrestrial vertebrate fauna. This is the first time such tests are employed to assess the effectiveness of indicator groups at the ecoregion level in Brazil. We show that patterns of species richness are highly correlated among mammals, birds, amphibians, and reptiles. Furthermore, we demonstrate that ecoregion sets selected according to endemic species richness captured more vertebrate species per unit area than sets based on overall vertebrate richness itself, or than those selected at random. Ecoregion sets based on endemic bird, endemic reptile, or endemic amphibian richness also performed well, capturing more species overall than random sets, or than those selected based on species richness of one or all vertebrate classes within ecoregions. Our results highlight the importance of evaluating biodiversity concordance and the use of indicator groups as well as aggregate species richness. We conclude that priority sets based on indicator groups provide a basis for a first assessment of priorities for conservation at an infracontinental scale. Areas with high endemism have long been highlighted for conservation of species. Our findings provide evidence that endemism is not only a worthwhile conservation goal, but also an effective surrogate for the conservation of all terrestrial vertebrates in Brazil.     

SURROGACY: DONOR CONCEPTION REGULATION IN JAPAN

As of 2008, surrogacy is legal and openly practised in various places; Japan, however, has no regulations or laws regarding surrogacy. This paper reports the situation of surrogacy in Japan and in five other regions (the USA, the UK, Taiwan, Korea and France) to clarify the pros and cons of prohibiting surrogacy, along with the problems and issues relating to surrogacy compensation. Not only in a country such as France that completely prohibits surrogacy within the country, but also in a country such as the UK that allows non‐commercial surrogacy, infertile couples travel overseas for the purpose of surrogacy. In addition, some couples might seek underground surrogacy if the government prohibits surrogacy. If an intended parent couple and a surrogate make an agreement among themselves and then a problem occurs, they cannot ask for support from professionals or bring a case to court, as can be observed in South Korea and Taiwan. We also conclude that there is little difference between commercial surrogacy and non‐commercial surrogacy in the absence of a clear definition of ‘reasonable expenses.’ In the UK, the law does not allow surrogates to receive compensation. However, in reality, there may be little difference between the amounts paid to surrogates for profit in the US and those paid to surrogates for reasonable expenses in the UK. We conclude that the issue of surrogacy demands further discussion in Japan.     

Effectiveness of biological surrogates for predicting patterns of marine biodiversity: a global meta-analysis

The use of biological surrogates as proxies for biodiversity patterns is gaining popularity, particularly in marine systems where field surveys can be expensive and species richness high. Yet, uncertainty regarding their applicability remains because of inconsistency of definitions, a lack of standard methods for estimating effectiveness, and variable spatial scales considered. We present a Bayesian meta-analysis of the effectiveness of biological surrogates in marine ecosystems. Surrogate effectiveness was defined both as the proportion of surrogacy tests where predictions based on surrogates were better than random (i.e., low probability of making a Type I error; P) and as the predictability of targets using surrogates (R(2)). A total of 264 published surrogacy tests combined with prior probabilities elicited from eight international experts demonstrated that the habitat, spatial scale, type of surrogate and statistical method used all influenced surrogate effectiveness, at least according to either P or R(2). The type of surrogate used (higher-taxa, cross-taxa or subset taxa) was the best predictor of P, with the higher-taxa surrogates outperforming all others. The marine habitat was the best predictor of R(2), with particularly low predictability in tropical reefs. Surrogate effectiveness was greatest for higher-taxa surrogates at a <10-km spatial scale, in low-complexity marine habitats such as soft bottoms, and using multivariate-based methods. Comparisons with terrestrial studies in terms of the methods used to study surrogates revealed that marine applications still ignore some problems with several widely used statistical approaches to surrogacy. Our study provides a benchmark for the reliable use of biological surrogates in marine ecosystems, and highlights directions for future development of biological surrogates in predicting biodiversity.     

Can higher taxa be used as a surrogate for species-level data in biodiversity surveys of litter/soil insects?

We investigate the usefulness of higher taxa as surrogates for species richness and diversity of litter/soil insects. We use data for Coleoptera (beetles) and Formicidae (ants) collected during biodiversity surveys of five tropical and two temperate countries, and use Pearson’s product moment correlations to assess the surrogacy relationship. Our results suggest that genera would provide an adequate surrogate for species richness of Coleoptera, but not for Formicidae. We suggest that the usefulness of higher taxa as surrogates for richness is dependent on both taxonomy and scale. Higher taxa provided a poor surrogate for species diversity due to the added dimension of evenness of community structure, and we recommend that higher taxa should not be used as surrogates for species diversity.     

Measuring the effectiveness of regional conservation assessments at representing biodiversity surrogates at a local scale: A case study in Réunion Island (Indian Ocean)

In a context of scarce financial and human resources, the allocation of conservation efforts needs to be optimized. Our analysis attempts to draw conclusions on the integration of regional and local conservation assessments, specifically, with regard to the acquisition of fine‐scale data to complement the regional assessment. This study undertaken in Réunion Island (Indian Ocean) assessed how biodiversity surrogates targeted at a regional scale represented other biodiversity surrogates at a local scale. Biodiversity surrogates at both scales consisted of species, habitats and processes. Habitats and processes at regional scale were defined using a coarser scale of thematic resolution than at local scale. The surrogacy was tested in terms of incidental representation of local‐scale features in the regional assessments, and correlation of irreplaceability values between scales. Near‐minimum sets and irreplaceability values were generated using MARXAN software. Our results revealed that conservation targets for processes at local scale were never met incidentally, while threatened species and fragmented habitats were also usually under‐represented. More specifically, requiring only 12% of the local planning domain, the application of species as surrogates at regional scale was the least effective option at representing biodiversity features at local scale. In contrast, habitats at a coarse scale of thematic resolution achieved a significant proportion of conservation targets incidentally (67%) and their irreplaceability values were well correlated with the irreplaceability values of surrogates at local scale. The results highlighted that all three types of biodiversity surrogates are complementary for assessing overall biodiversity. Because of the cost of data acquisition, we recommended that the most efficient strategy to develop nested regional/local conservation plans is to apply habitats and processes at a coarse scale of thematic resolution at regional scale, and threatened species and degraded habitats at local scale, with their fine‐scale mapping limited to highly transformed areas.     

Robust approach to combining multiple markers to improve surrogacy

Identifying effective and valid surrogate markers to make inference about a treatment effect on long-term outcomes is an important step in improving the efficiency of clinical trials. Replacing a long-term outcome with short-term and/or cheaper surrogate markers can potentially shorten study duration and reduce trial costs. There is sizable statistical literature on methods to quantify the effectiveness of a single surrogate marker. Both parametric and nonparametric approaches have been well developed for different outcome types. However, when there are multiple markers available, methods for combining markers to construct a composite marker with improved surrogacy remain limited. In this paper, building on top of the optimal transformation framework of Wang et al. (2020), we propose a novel calibrated model fusion approach to optimally combine multiple markers to improve surrogacy. Specifically, we obtain two initial estimates of optimal composite scores of the markers based on two sets of models with one set approximating the underlying data distribution and the other directly approximating the optimal transformation function. We then estimate an optimal calibrated combination of the two estimated scores which ensures both validity of the final combined score and optimality with respect to the proportion of treatment effect explained by the final combined score. This approach is unique in that it identifies an optimal combination of the multiple surrogates without strictly relying on parametric assumptions while borrowing modeling strategies to avoid fully nonparametric estimation which is subject to the curse of dimensionality. Our identified optimal transformation can also be used to directly quantify the surrogacy of this identified combined score. Theoretical properties of the proposed estimators are derived, and the finite sample performance of the proposed method is evaluated through simulation studies. We further illustrate the proposed method using data from the Diabetes Prevention Program study.     

Using null model analysis of species co-occurrences to deconstruct biodiversity patterns and select indicator species

Aim Using total species richness to characterize biodiversity may mask multiple response patterns of species. We propose a null model analysis of species co‐occurrence‐based classification to identify sets of species that may have similar (within‐groups) and distinct (between groups) response patterns to their environment. The classification should also provide an explicit framework for selecting indicator species with characteristic co‐occurrence patterns to predict overall species richness. Location Côte‐Nord, Québec, Canada. Methods We combined null‐model of species co‐occurrence and cluster analysis to identify species groups within diverse assemblages of ground‐dwelling and flying beetles of stands in a boreal forest mosaic; we then examined their co‐occurrence and response patterns to habitat characteristics. Best subset regressions were used to select indicator species of richness within each group, from which indicators of total species richness were selected. Results The identified species groups appeared to display contrasting co‐occurrence and response patterns to at least one of the stand‐level habitat characteristics. Among flying beetles, for example, richness increased with stand‐level heterogeneity for two groups and decreased for two other groups, but the relationship was non‐significant for the total richness. We identified 28 indicator species that explained > 80% (validated by bootstrap analysis) of the variation in total species richness. Predictive performance of indicators was higher than when their co‐occurrence were reshuffled, even under a highly constrained null model, indicating that co‐occurrence patterns contributed to their predictive performance. Main conclusions Co‐occurrence‐based classification appears as a promising and effective tool for deconstructing biodiversity into species groups which reflect their ecological commonalities and differences, thus reducing the risk of making faulty inferences about the causes underlying overall diversity patterns. The method provides an explicit framework for selecting indicator species representing different species groups that may reflect the multiple responses of species co‐occurring with them. Indicator species can be effective for predicting overall species richness.     

Monitoring marine macroalgae: the influence of spatial scale on the usefulness of biodiversity surrogates

Aim To examine the influence of spatial scale on the usefulness of commonly employed biodiversity surrogates in subtidal macroalgae assemblages. Location South‐west Australia. Methods The relationship between biodiversity surrogates and univariate and multivariate species‐level patterns was tested at multiple spatial scales, ranging from metres (between quadrats) to hundreds of kilometres (between regions), using samples collected from almost 2000 km of temperate coastline that represented almost 300 species. Biodiversity surrogates included commonly used cost‐effective alternatives to species‐level sampling, such as those derived from functional groups and from taxonomic aggregation. Results Overall, surrogates derived from taxonomic aggregation to genus or family level correlated strongly with species‐level patterns, although the family‐level surrogate was a less effective predictor of species richness at large spatial scales. Surrogates derived from aggregation to coarser taxonomic levels and functional groups performed poorly, while the effectiveness of a surrogate measure derived from canopy‐forming species improved with increasing spatial scale. Main conclusions A critical, but rarely examined, assumption of biodiversity surrogates is that the relationship between surrogate and species‐level patterns is consistent in both space and time, and across a range of spatial and temporal scales. As the performance of all surrogates was, to some degree, scale‐dependent, this work empirically demonstrated the need to consider the spatial extent and design of any biodiversity monitoring programme when choosing cost‐effective alternatives to species‐level data collection.     

The surrogacy potential of white-tailed sea eagle nesting habitat on islands of the Baltic Sea

In order to tackle the current biodiversity crisis, a plethora of tempting shortcuts, such as the surrogate species approach, have recently been used to pinpoint important areas for protection. At the same time, species-specific conservation programmes are implemented in order to ameliorate the status of target threatened species. In the cases where species-specific programmes are evaluated and found to provide no apparent benefit to the target species, it is important to evaluate whether such conservation efforts may benefit other taxa sharing the same landscape with the target species. Here we assess the surrogacy potential of white-tailed sea eagle (WTSE) nesting habitat as indicator of biodiversity richness (using vascular plants and fungi as surrogated taxa) on islands of the Archipelago Sea in South-western Finland. We compared species richness on islands with and without a WTSE nest. We found weak evidence that islands with a WTSE nest support higher richness of vascular plants than islands without a nest. Conversely, we found no evidence that WTSE nests could be valid surrogates for fungi species inhabiting old-growth forests. Within the spatio-temporal and ecological limits of the present study, we suggest that the nesting habitat of WTSE may hold some surrogate potential for taxa, such as vascular plants, that may indicate high habitat diversity. This finding however remains to be confirmed. At the same time, it appears evident that the WTSE nesting habitat has poor surrogate potential with regards to old-growth forests. Overall, our findings line up with a growing body of other studies calling for caution and careful evaluation of the surrogacy efficiency of single species.     

Biogeographical concordance and efficiency of taxon indicators for establishing conservation priority in a tropical rainforest biota

Prioritizing areas for conservation requires the use of surrogates for assessing overall patterns of biodiversity. Effective surrogates will reflect general biogeographical patterns and the evolutionary processes that have given rise to these and their efficiency is likely to be influenced by several factors, including the spatial scale of species turnover and the overall congruence of the biogeographical history. We examine patterns of surrogacy for insects, snails, one family of plants and vertebrates from rainforests of northeast Queensland, an area characterized by high endemicity and an underlying history of climate-induced vicariance. Nearly all taxa provided some level of prediction of the conservation values for others. However, despite an overall correlation of the patterns of species richness and complementarity, the efficiency of surrogacy was highly asymmetric; snails and insects were strong predictors of conservation priorities for vertebrates, but not vice versa. These results confirm predictions that taxon surrogates can be effective in highly diverse tropical systems where there is a strong history of vicariant biogeography, but also indicate that correlated patterns for species richness and/or complementarity do not guarantee that one taxon will be efficient as a surrogate for another. In our case, the highly diverse and narrowly distributed invertebrates were more efficient as predictors than the less diverse and more broadly distributed vertebrates.     

Higher taxa as surrogates of species richness of spiders in insect‐resistant transgenic rice

Abstract Biodiversity assessments can often be time‐ and resource‐consuming. Several alternative approaches have been proposed to reduce sampling efforts, including indicator taxa and surrogates. In this study, we examine the reliability of higher taxon surrogates to predict species richness in two experimental rice fields of Fujian Province, southeastern China during 2005 and 2009. Spider samples in transgenic and nontransgenic plots were collected using a suction sampler. Both the genus and family surrogates had significant and positive linear relationships with species richness in the transgenic and nontransgenic rice fields. The rice varieties did not significantly influence the linear relationships. Our findings suggest that higher‐taxon surrogacy could be a useful alternative to complete species inventory for risk assessments of transgenic rice.     

Assessing the mechanisms behind successful surrogates for biodiversity in conservation planning

Limited by the availability of data, conservation planners must use surrogates for biodiversity when selecting conservation areas. Although several methods have been proposed for selecting surrogates, no clear set of species attributes have been described that allow for the efficient a priori selection of surrogate groups. We used a database of 1449 species in two regions of the United States to (1) examine the consistency in the performance of simple taxonomic-based surrogates of biodiversity and (2) test five hypotheses proposed to explain surrogate performance. First, we compared the ability of sites selected to protect members of seven surrogate groups to protect non-surrogate species in the north-western United States and in the Middle-Atlantic region of the eastern United States. Then, in a separate analysis, we tested whether surrogate performance could be explained by (1) taxonomic diversity; (2) nested species distributions; (3) hotspots of biodiversity; (4) species range sizes; (5) environmental diversity. Our first analysis revealed little consistency in the performance of surrogates in the two different study regions. For example, butterflies provided protection for 76% of all other species in the north-western United States but only 56% of all other species in the eastern United States. Our second analysis revealed only weak associations between species characteristics and surrogate performance. Furthermore, these associations proved inadequate for selecting successful surrogates across study regions. Overall, our results suggest that in lieu of searching for optimal surrogate groups, research efforts will be better spent by developing alternative methods for assessing conservation value in areas where data on species distributions are limited.     

Enhancing autonomy in paid surrogacy

The gestational surrogate – and her economic and educational vulnerability in particular – is the focus of many of the most persistent worries about paid surrogacy. Those who employ her, and those who broker and organize her services, usually have an advantage over her in resources and information. That asymmetry exposes her to the possibility of exploitation and abuse. Accordingly, some argue for banning paid surrogacy. Others defend legal permission on grounds of surrogate autonomy, but often retain concerns about the surrogate. In response to the dilemma of a ban versus bald permission, we propose a 'soft law' approach: states should require several hours of education of surrogates – education aimed at informing and enhancing surrogate autonomy.