Measuring insect rarity: practical issues, pragmatic approaches

2013 ◽  
Vol 1 (10) ◽  
pp. 1 ◽  
Author(s):  
Simone Fattorini ◽  
Andrea Di Giulio ◽  
Leonardo Dapporto

Rarity is often considered an indication of species extinction risk, and rarity measures are used as important tools to predict species vulnerability and hence to establish conservation priorities. For these reasons, rarity is among the most important issues involved in conservation programs. A number of studies have attempted to investigate relationships between rarity and extinction risk in plants and vertebrates, whereas only few papers have investigated similar issues in invertebrate taxa. This has limited the use of standardized rarity measures in invertebrate conservation studies. Assessing rarity is especially important when other pieces of information are difficult, or even definitively impossible, to obtain, as commonly found for most insects. Four broad categories of rarity are commonly recognized: geographical, ecological, population and phylogenetic rarity. On the basis of this framework, we present here a short review of the rarity forms most frequently investigated in insect studies, and their relationships with the main species traits related to extinction risk (such as body size, mobility, trophic level, host specificity, larval and adult behaviours, etc.). We discuss what they mean, how they can be measured, which type of data (field collections, museum data, literature information) are needed and how to avoid the most common pitfalls associated with rarity studies, with indications for pragmatic approaches in data analysis.

2021 ◽  
Author(s):  
Yuxi Zhong ◽  
Chuanwu Chen ◽  
Yanping Wang

Abstract China is a country with one of the most species rich reptile faunas in the world. However, nearly a quarter of Chinese lizard species assessed by the China Biodiversity Red List are threatened. Nevertheless, to date, no study has explicitly examined the pattern and processes of extinction and threat in Chinese lizards. In this study, we conducted the first comparative phylogenetic analysis of extinction risk in Chinese lizards. We addressed the following three questions: 1) What is the pattern of extinction and threat in Chinese lizards? 2) Which species traits and extrinsic factors are related to their extinction risk? 3) How can we protect Chinese lizards based on our results? We collected data on ten species traits (body size, clutch size, geographic range size, activity time, reproductive mode, habitat specialization, habitat use, leg development, maximum elevation, and elevation range) and seven extrinsic factors (mean annual precipitation, mean annual temperature, mean annual solar insolation, normalized difference vegetation index (NDVI), human footprint, human population density, and human exploitation). After phylogenetic correction, these variables were used separately and in combination to assess their associations with extinction risk. We found that Chinese lizards with small geographic range, large body size, high habitat specialization, and living in high precipitation areas were vulnerable to extinction. Conservation priority should thus be given to species with the above extinction-prone traits so as to effectively protect Chinese lizards. Preventing future habitat destruction should also be a primary focus of management efforts because species with small range size and high habitat specialization are particularly vulnerable to habitat loss.


2010 ◽  
Vol 278 (1711) ◽  
pp. 1532-1538 ◽  
Author(s):  
Michael J. O. Pocock

Species' traits have been used both to explain and, increasingly, to predict species' vulnerability. Trait-based comparative analyses allow mechanisms causing vulnerability to be inferred and, ideally, conservation effort to be focused efficiently and effectively. However, empirical evidence of the predictive ability of trait-based approaches is largely wanting. I tested the predictive power of trait-based analyses on geographically replicated datasets of farmland bird population trends. I related the traits of farmland passerines with their long-term trends in abundance (an assessment of their response to agricultural intensification) in eight regions in two continents. These analyses successfully identified explanatory relationships in the regions, specifically: species faring badly tended to be medium-sized, had relatively short incubation and fledging periods, were longer distant migrants, had small relative brain sizes and were farmland specialists. Despite this, the models had poor ability to predict species' vulnerability in one region from trait–population trend relationships from a different region. In many cases, the explained variation was low (median R 2 = 8%). The low predictive ability of trait-based analyses must therefore be considered if such trait-based models are used to inform conservation priorities.


2018 ◽  
Author(s):  
Filipe Chichorro ◽  
Aino Juslén ◽  
Pedro Cardoso

ABSTRACTBiodiversity is shrinking rapidly, and despite our efforts only a small part of it has been assessed for extinction risk. Identifying the traits that make species vulnerable might help us to predict the outcome for those less known. We gathered information on the relations of traits to extinction risk from 173 publications, across all taxa, spatial scales and biogeographical regions, in what we think it is the most comprehensive compilation to date. Vertebrates and the Palaearctic are the most studied taxon and region because of higher accumulation of data in these groups. Among the many traits that have been suggested to be good predictors, our meta-analyses were successful in identifying two as potentially useful in assessing risk for the lesser-known species: regardless of the taxon, species with small range and habitat breadth are more vulnerable to extinction. On the other hand, body size (the most studied trait) did not present a consistently positive or negative response. In line with recent research, we hypothesize that the relationship between body size and extinction risk is shaped by different aspects, namely body size is a proxy for different phenomena depending on the taxonomic group.


2013 ◽  
Vol 63 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Simone Fattorini

A number of studies have attempted to investigate which species traits influence species proneness to extinction in vertebrates. By contrast, studies involving insects are scarce, because of difficulties in obtaining complex assessments of species extinction risk and measures of species traits. In this paper, a simple (binary) codification based on literature data and field observations was used to determine the importance of various traits (notably ecological preferences) in determining species vulnerability of the tenebrionid beetles inhabiting urban Rome (Italy). Vulnerability scores were calculated from measures of geographical, habitat and population rarity. Vulnerable species were distributed with similar proportions among different tenebrionid guilds, which suggests that conservation programs in urban ecosystems should be more addressed to the development of species-oriented actions than to the identification of priority ‘habitats’. Species traits accurately predicted species assignment to vulnerability classes, with some traits being particularly important in determining species vulnerability. Species associated with ruins and cellars, and which are typically fairly common in Rome, tend to be moderately or middle vulnerable. The identification of important sites for these species and definition of measures for population management would be useful strategies to preserve them.


2015 ◽  
Vol 47 (2) ◽  
pp. 53 ◽  
Author(s):  
Giuseppe Maria Carpaneto ◽  
Cosimo Baviera ◽  
Alessandro Bruno Biscaccianti ◽  
Pietro Brandmayr ◽  
Antonio Mazzei ◽  
...  

The main objectives of this review are: 1) the compilation and updating of a reference database for Italian saproxylic beetles, useful to assess the trend of their populations and communities in the next decades; 2) the identification of the major threats involving the known Italian species of saproxylic beetles; 3) the evaluation of the extinction risk for all known Italian species of saproxylic beetles; 4) the or- ganization of an expert network for studying and continuous updating of all known species of saproxylic beetle species in Italy; 5) the creation of a baseline for future evaluations of the trends in biodiversity conservation in Italy; 6) the assignment of ecological categories to all the Italian saproxylic beetles, useful for the aims of future researches on their communities and on forest environments. The assess- ments of extinction risk are based on the IUCN Red List Categories and Criteria and the most updated guidelines. The assessments have been carried out by experts covering different regions of Italy, and have been evaluated according to the IUCN standards. All the beetles whose larval biology is sufficiently well known as to be considered saproxylic have been included in the Red List, either the autochtho- nous species (native or possibly native to Italy) or a few allochthonous species recently introduced or probably introduced to Italy in his- toric times. The entire national range of each saproxylic beetle species was evaluated, including large and small islands; for most species, the main parameters considered for evaluation were the extent of their geographical occurrence in Italy, and the number of known sites of presence. 2049 saproxylic beetle species (belonging to 66 families) have been listed, assigned to a trophic category (Table 3) and 97% of them have been assessed. On the whole, threatened species (VU + EN + CR) are 421 (Fig. 6), corresponding to 21 % of the 1988 as- sessed species; only two species are formally recognized to be probably Regionally Extinct in Italy in recent times. Little less than 65% of the Italian saproxylic beetles are not currently threatened with extinction, although their populations are probably declining. In forest environments, the main threats are habitat loss and fragmentation, pollution due to the use of pesticide against forest pests, and habitat simplification due to economic forest management. In coastal environments, the main threats are due to massive touristic exploitation such as the excess of urbanization and infrastructures along the seashore, and the complete removal of woody materials as tree trunks stranded on the beaches, because this kind of intervention is considered an aesthetic amelioration of seaside resorts. The number of spe- cies whose populations may become impoverished by direct harvest (only a few of large forest beetles frequently collected by insect traders) is very small and almost negligible. The Red List is a fundamental tool for the identification of conservation priorities, but it is not a list of priorities on its own. Other elements instrumental to priority setting include the cost of actions, the probability of success,and the proportion of the global population of each species living in Italy, which determines the national responsibility in the long-term conservation of that species. In this scenario, information on all species endemic to Italy, to Corso-Sardinia, to the Tuscan-Corsican ar- eas, and to the Siculo-Maltese insular system are given. A short analysis on relationships among beetle species traits, taxonomy, special- ist approaches, and IUCN Categories of Risk is also presented.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Maggie M. Hantak ◽  
Bryan S. McLean ◽  
Daijiang Li ◽  
Robert P. Guralnick

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.


2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Beth A. Polidoro ◽  
Cristiane T. Elfes ◽  
Jonnell C. Sanciangco ◽  
Helen Pippard ◽  
Kent E. Carpenter

Given the economic and cultural dependence on the marine environment in Oceania and a rapidly expanding human population, many marine species populations are in decline and may be vulnerable to extinction from a number of local and regional threats. IUCN Red List assessments, a widely used system for quantifying threats to species and assessing species extinction risk, have been completed for 1190 marine species in Oceania to date, including all known species of corals, mangroves, seagrasses, sea snakes, marine mammals, sea birds, sea turtles, sharks, and rays present in Oceania, plus all species in five important perciform fish groups. Many of the species in these groups are threatened by the modification or destruction of coastal habitats, overfishing from direct or indirect exploitation, pollution, and other ecological or environmental changes associated with climate change. Spatial analyses of threatened species highlight priority areas for both site- and species-specific conservation action. Although increased knowledge and use of newly available IUCN Red List assessments for marine species can greatly improve conservation priorities for marine species in Oceania, many important fish groups are still in urgent need of assessment.


2018 ◽  
Vol 24 (3) ◽  
pp. 267
Author(s):  
Lesley Hughes

‘The Greenhouse Effect and Nature Reserves’ by Robert Peters and Joan Darling, published in the journal Bioscience more than 30 years ago, was a ground-breaking synthesis. Drawing on paleoecology, community ecology and biogeography, the review laid out many concepts about species vulnerability to climate change that have become central tenets of research on climate change adaptation in natural ecosystems. Remarkably, the paper also provided a clear and logical framework for flexible, forward-thinking and interventionist management action, including recommendations about the design of protected areas, and the need for species translocation to reduce extinction risk. Reflecting on the legacy of this paper, it is clear that the uptake of such approaches over the intervening decades has been extremely slow, representing many lost opportunities to reduce species vulnerability to rapid environmental change. This paper is a tribute to the prescience of Peters and Darling, and a call to revisit their farsighted advice to meet conservation challenges that continue to accelerate.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5370 ◽  
Author(s):  
Caterina Penone ◽  
Christian Kerbiriou ◽  
Jean-François Julien ◽  
Julie Marmet ◽  
Isabelle Le Viol

Background Citizen monitoring programs using acoustic data have been useful for detecting population and community patterns. However, they have rarely been used to study broad scale patterns of species traits. We assessed the potential of acoustic data to detect broad scale patterns in body size. We compared geographical patterns in body size with acoustic signals in the bat species Pipistrellus pipistrellus. Given the correlation between body size and acoustic characteristics, we expected to see similar results when analyzing the relationships of body size and acoustic signals with climatic variables. Methods We assessed body size using forearm length measurements of 1,359 bats, captured by mist nets in France. For acoustic analyses, we used an extensive dataset collected through the French citizen bat survey. We isolated each bat echolocation call (n = 4,783) and performed automatic measures of signals, including the frequency of the flattest part of the calls (characteristic frequency). We then examined the relationship between forearm length, characteristic frequencies, and two components resulting from principal component analysis for geographic (latitude, longitude) and climatic variables. Results Forearm length was positively correlated with higher precipitation, lower seasonality, and lower temperatures. Lower characteristic frequencies (i.e., larger body size) were mostly related to lower temperatures and northern latitudes. While conducted on different datasets, the two analyses provided congruent results. Discussion Acoustic data from citizen science programs can thus be useful for the detection of large-scale patterns in body size. This first analysis offers a new perspective for the use of large acoustic databases to explore biological patterns and to address both theoretical and applied questions.


2016 ◽  
Vol 12 (10) ◽  
pp. 20150813 ◽  
Author(s):  
Wolfgang Kiessling ◽  
Ádám T. Kocsis

Besides helping to identify species traits that are commonly linked to extinction risk, the fossil record may also be directly relevant for assessing the extinction risk of extant species. Standing geographical distribution or occupancy is a strong predictor of both recent and past extinction risk, but the role of changes in occupancy is less widely assessed. Here we demonstrate, based on the Cenozoic fossil record of marine species, that both occupancy and its temporal trajectory are significant determinants of risk. Based on extinct species we develop a model on the additive and interacting effects of occupancy and its temporal changes on extinction risk. We use this model to predict extinction risk of extant species. The predictions suggest a moderate risk for marine species on average. However, some species seem to be on a long-term decline and potentially at a latent extinction risk, which is not considered in current risk assessments.


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