Adapting the IUCN Red List criteria for invertebrates

The IUCN Red List is the most useful list of species that are at risk for extinction worldwide, as it relies on a number of objective criteria. Nevertheless, there is a taxonomic bias that excludes species with small body sizes, narrow distribution ranges and low dispersal abilities, which constitute the vast majority of the planet’s biota, particularly local endemics.By evaluating each IUCN criterion separately, we (i) identify the shortcomings for invertebrate applications, (ii) explain how risk categories may be wrongly applied due to inapplicable and/or misleading thresholds, (iii) suggest alternative ways of applying the existing criteria in a more realistic way and (iv) suggest possible new criteria that were not considered in the current evaluation framework but that could allow a more comprehensive and effective assessment of invertebrates.By adapting the criteria to rely more explicitly on the Area of Occupancy and the Extent of Occurrence, their respective trends and by using ecological modelling methods, the criteria’s applicability would be increased. The change in some thresholds or, eventually, the creation of sub-categories would further increase their adequacy. Additionally, co-extinction could be introduced as an explicit part of the classification process.As a case study, we evaluated 48 species of Azorean arthropods and Iberian spiders according to the current criteria. More than one-quarter (27%) of all evaluated species were classified as Critically Endangered, 19% as Endangered, 6% as Vulnerable and 8% as Least Concern. The remaining 40% did not have enough data to reach a classification.     

Applying IUCN Red List criteria at a small regional level: A test case with butterflies in Flanders (north Belgium)

Red Lists are used to assess the extinction risk of species based on quantitative IUCN criteria. For the compilation of a new Red List of butterflies in Flanders (north Belgium), we collated ca 800,000 distribution records and applied the IUCN Red List criteria to this small region (ca 135,00 km²). We also explored the effect of spatial resolution on the outcome of the Red List assessment by alternatively using 1 × 1 km² and 5 × 5 km² grid cells for geographic range size and trend calculations. We determined conservation hot spots in Flanders based on the Red List status of the species composition in each grid cell. The new Red List classified 20 butterflies (out of 68 resident species) as Regionally Extinct, six as Critically Endangered, five as Endangered, seven as Vulnerable and seven as Near Threatened. The remaining 23 species were classified as Least Concern. Using coarse instead of fine grain grid cells would have classified ten species in a lower Red List category. Compared with the previous Red List, nine species were classified in a lower and 12 in a higher threat category. In total, 218 1 × 1 km² grid cells were considered as (very) high butterfly conservation priority sites. The application of the new IUCN criteria in a small region such as Flanders resulted in a Red List that offered challenging opportunities for the conservation of butterflies in particular and biodiversity in general.     

Adapting global biodiversity indicators to the national scale: A Red List Index for Australian birds

The Red List Index (RLI), which uses information from the IUCN Red List to track trends in the projected overall extinction risk of sets of species, is among the indicators adopted by the world’s governments to assess performance under the Convention on Biological Diversity and the United Nations Millennium Development Goals. For greatest impact, such indicators need to be measured and used at a national scale as well as globally. We present the first application of the RLI based on assessments of extinction risk at the national scale using IUCN’s recommended methods, evaluating trends in the status of Australian birds for 1990–2010. We calculated RLIs based on the number of taxa in each Red List category and the number that changed categories between assessments in 1990, 2000 and 2010 as a result of genuine improvement or deterioration in status. A novel comparison between trends at the species and ultrataxon (subspecies or monotypic species) level showed that these were remarkably similar, suggesting that current global RLI trends at the species level may also be a useful surrogate for tracking losses in genetic diversity at this scale, for which no global measures currently exist. The RLI for Australia is declining faster than global rates when migratory shorebirds and seabirds are included, but not when changes resulting from threats in Australia alone are considered. The RLI of oceanic island taxa has declined faster than those on the continent or on continental islands. There were also differences in the performance of different jurisdictions within Australia.     

The impacts of invasive rodents on island invertebrates

The widespread invasive rodents Rattus norvegicus, R. rattus, R. exulans and Mus musculus have been implicated in the decline and extinction of hundreds of island endemic vertebrates, but their effects on island invertebrates are less well-known. Here I present the first global review of the subject, which confirms that large-bodied invertebrates are most at risk from these rodents, and that although a disproportionate number of studies (69%) are from New Zealand, rodent-invertebrate impacts are geographically widespread. Mechanisms of impact are both direct (mediated by predation) and indirect (involving intermediary species). Some studies also suggest knock-on effects on ecosystem properties, and given the diverse ecological functions of invertebrates (as detritivores, primary consumers, predators, prey and pollinators), I suggest that an understanding of the interactions between invasive rodents and invertebrates in island ecosystems is essential for effective conservation management. Currently many reported impacts are unquantified, come from uncontrolled and unreplicated designs, or rely on time-series with inadequate baseline data. In addition to basic improvements in study design, this review highlights a need for studies which investigate mechanisms of impact, or impacts across trophic levels.     

The status of marine turtles in the Egyptian Red Sea

Five species of marine turtle occur in the Egyptian Red Sea and three are recognised by local fishermen: Eretmochelys imbricata (L.), Chelonia mydas (L.), and Dermochelys coriacea (L.). The last named is rarely sighted, and although the other two nest, only Eretmochelys is common; possibly 500 nest yearly, mainly on offshore islands. Both nesting and feeding habitats appear to be extensive for this species, but clutches have an unusually high percentage of yolkless eggs. The significance of this is not understood, but it indicates that the animals are under pressures not experienced in other parts of their range. The small population of Chelonia is probably due to the scarcity of feeding habitat; marine pastures are generally small in area and standing crop. Dermochelys may be rarely sighted because local fishermen infrequently venture into epipelagic waters where this animal is most common, but the available data indicate that the species is a vagrant in Egypt. The enormous swarms of jellyfish that occur in the Egyptian Red Sea evidently do not attract these turtles, although seasonal concentrations of jellyfish are often accompanied by Dermochelys in other seas. Exploitation of turtles, mainly for meat and eggs, is slight, but habitat perturbations are intense from oil pollution and marine explosions. There is a great need for more basic information and rigorous management of the marine environment.     

Red List assessment of nine <Emphasis Type="Italic">Aegilops</Emphasis> species in Armenia

The aims of this study are to determine the geographical and ecological distribution of nine Aegilops species in Republic of Armenia and to make an assessment of their IUCN Red List status, using the IUCN Red list categories and criteria, in order to develop an in situ conservation strategy for wild relatives of wheat in Armenia. Ecogeographic surveys of nine Aegilops species were undertaken over 2 years in Armenia. They included a herbarium survey followed by extensive ground-truthing field surveys where targeted Aegilops species occur. The study showed that of the nine Aegilops species studied, four are threatened and of these, Ae. mutica and Ae. crassa are critically endangered. The latter species may even be extinct in Armenia. Ae. neglecta and A. biuncialis are endangered. Additional studies are required to assess the threat status of Ae. umbellulata. Ae. columnaris was assessed as near threatened, while the remaining species (Ae. triuncialis, Ae. cylindrica and Ae. tauschii) are of least concern. There has been a dramatic decline in the genetic resources of Aegilops species during recent years in Armenia as a result of adverse human impacts such as expansion of agriculture, urbanization and uncontrolled grazing. Several species, especially Ae. mutica and Ae. crassa, should be prioritized in conservation activities in Armenia. Efforts should be made to conserve genetic diversity of crop wild relative species both in situ and ex situ, bearing in mind that their germplasm carries potentially valuable information (traits) that can improve adaptability and productivity of cultivated wheat varieties.     

Soil invertebrates and the degradation of vanillin,cinnamic acid,and lignins

A range of 8–25% of fed cinnamic 2-[¹⁴C] acid and 9–14% of injected vanillin 5-[¹⁴C] were oxidised to ¹⁴CO₂ at 15 C over 7 and 6 days respectively in an isopod, Oiuscus asellus; a millipede, Pseudopolydesmus serratus; a slug, Deroceras reticulatum; a snail, Oxychilus draparnaldi; and an earthworm, Eisenia foetida. Approximately 2–10% of nonmetabolised and 13–48%, of metabolised vanillin were present in the animal tissues after 6 days. Correspondingly. 1–4% and 22–66% of these materials were found in egesta.A millipede (Oxidus gracilis), O. asellus. D. reticuluttum. O. draparnaldi, and E. foetida were found unable to degrade ring [¹⁴C]-, methoxy [¹⁴C]- and side chain [¹⁴C]-lignin to ¹⁴CO₂ over 10 days, thus providing very strong evidence that these invertebrates are incapable of degrading liginin.     

Conservation and the low population density of invertebrates inside neotropical rain forest

Counts of invertebrates by sweep-netting and beating the stratum of rain forest vegetation between 6 in (15 cm) and 6 ft (1·8 m) have been made during rainy season conditions in N. Brasil and on Barro Colorado Island, Panama Canal, the latter from measured volumes of habitat. This work has been repeated on BCI during the dry season. The average population densities of total catches were 0·97 m³ for rainy season and 1·09 m³ for dry season. Species diversity was very high, therefore numbers per species extremely low. It is suggested that such low population density brings hazards of local extinction, and that the maintenance of such a system depends on the existence of extensive habitat from which recolonisation can occur. If this is so, reserves in rain forest will have to be very large, to ensure long-term survival of many of the invertebrate species.     

Changes in the community structure and diversity of soil invertebrates across the Franz Josef Glacier chronosequence

Following the creation of new land surfaces, there is an initial build-up phase of ecosystem development, but after a prolonged absence of major disturbance a retrogressive (decline) phase often follows due to reduced nutrient availability over time. Although many studies have considered how the soil community changes during the build-up phase, the response of this community to the retrogressive phase is poorly known. We measured litter and soil communities of microfauna and macrofauna along the Franz Josef Glacier chronosequence in New Zealand that spans ca. 120,000 years, and includes well-established build-up and retrogressive stages. We aimed to assess whether the abundances, community structure and diversity of these groups show the same pattern across the sequence as that for vegetation. With regard to microfaunal abundances, litter-dwelling microbe-feeding nematodes were most abundant in the first stage of the chronosequence, but several other groups of microfauna in both the soil and litter increased sharply during the first few stages and declined sharply during the last (retrogressive) stages. The ratios of bacterial- to fungal-feeding nematodes in both soil and litter were lowest for the final stages of the chronosequence, and (in the case of soil) for some of the early stages, pointing to domination by the fungal-based energy channel at those stages for which soil organic matter content or quality were lowest. This is consistent with the fungal-based energy channel being better adapted than the bacterial-based channel for resource-poor conditions. The main groups of macroinvertebrates typically had their lowest abundances at the very early and late stages of the chronosequence, although the relative abundances of different taxa differed during the intermediate stages. Taxonomic diversity of nematodes and macroinvertebrates in both litter and soil varied strongly with chronosequence stage but differed among taxa; diversity of only one group (macroinvertebrates in litter) declined significantly during retrogression. Diversity of nematodes and macroinvertebrates along the sequence did not closely match tree diversity or soil chemical properties, but community composition of these groups was often related to tree community composition and ratios of soil C to N, C to P and N to P. Different groups of soil invertebrates show contrasting responses to chronosequence stage, probably because they differ in their relative response to bottom-up and top-down controls. However, the abundance of most groups increased during the build-up phase and declined during retrogression. As such, the build-up and decline phases observed for plant communities and ecosystem processes across long-term chronosequences also apply to soil communities, pointing to the importance of resource availability as a major driver of soil biota during long-term ecosystem change.     

Influence of acidification and aluminum on the density and biomass of lotic benthic invertebrates

Experiments were carried out in plasticized wooden channels fed by a small creek in the Reserve des Laurentides, 80 km north of Quebec city. Channels were naturally colonized by invertebrates for 65 d before treatment. Treated channels were acidified in August with dilute H₂SO₄ only, or with acid plus a solution of Al sulfate (final concentration of 0.19 mg L^?1). The control channel received creek water only (pH 6.3 to 6.9). The addition of Al had no effect on invertebrate density and biomass. After 73 d of acidification, invertebrate densities were only one third the number found in the control channel. Invertebrate hiomass was not different within channels, although biomass was generally higher in the two acidified channels. Difference in densities between acidified and non-acidified channels was attributed to lack of colonization and not to an increase in drift. Microtendipes, a large and resistant larva of Chironomidae constituted a large fraction of the hiomass, largely outweighing numerous very small larvae. Effects on the density were attributed to the direct effect of low pH and not to indirect action through food limitations.     

Methane release from millipedes and other soil invertebrates in Central Europe

The potential for methane production was investigated in 47 species of soil invertebrates. No detectable methane production was found in slugs, earthworms, potworms, oribatid mites, woodlices, springtails, centipedes, ants and soil diptera larvae. However, significant methane production was found in several temperate millipedes including some species from the order Julida (Leptoiulus trilobatus, Megaphyllum projectum, Megaphyllum unilineatum, Unciger transsilvanicus, Unciger foetidus, Leptoiulus proximus and Julus scandinavius). On the other hand, methane production was not confirmed in Cylindroiulus boleti which belongs to the same family. Members of the other orders (Glomerida and Polydesmida) did not release methane with the exception of one questionable recorded release in Polydesmus complanatus (Polydesmida, Polydesmidae). Methane producing species of millipedes showed significantly lower weight-specific rates of methane release than the cockroach Periplaneta americana and termite Prorhinotermes simplex. Methane release from millipedes was temperature-dependent; for the temperature range 5-25 °C, a Q₁₀ between 1.55 and 2.17 was calculated and the relationship between methane release and temperature was described by an exponential curve. Our results suggest that although overall methane fluxes from soil invertebrates under study cannot substantially influence a methane budget in most ecosystems, methane production is significant at least in some millipedes and therefore can impact mesoenvironments and microenvironments inhabited by these invertebrates. This work also confirms that methane production is not only supported by tropic soil invertebrates, but also by temperate species.     

Communities of microorganisms and invertebrates in soil-like bodies of soccer fields in Moscow oblast

Artificially created soil-like technogenic formations (STFs) of soccer fields are developed under combined action of intense technogenic and natural factors and processes, which cannot but affect the structure and biological activity of their microbial communities and mesofauna. The microflora of the STFs is very similar to the microflora of the background soddy-podzolic soils of Moscow oblast with respect to the composition of the physiological groups of microorganisms. However, they are drastically different in their quantitative characteristics. The numbers of all the trophic groups of microorganisms, except for the microscopic fungi, in the STFs are much higher than those in the zonal soils. An increased biological activity of the STFs is due to regular watering, heating, application of sand and mineral fertilizers, and technogenic turbation processes. The mesofauna of the STFs is represented by several ecological groups of earthworms, including soildwelling (endogeic) earthworms (Aporrectodea caliginosa), epigeic earthworms dwelling at the soil-litter interface (Lumbricus rubellus), and litter-dwelling earthworms (Eisenia foetida).     

The responses of leaf litter invertebrates to environmental gradients along road edges in subtropical island forests

Knowledge of how roads affect forest biodiversity can be improved by measuring the responses of indicator species to complex environmental gradients caused by these infrastructures. We studied litter invertebrate species responses to road edges in laurel and pine forests in Tenerife, Canary Islands. We sampled invertebrates from litter and assessed the environmental variation related to road proximity. We also assessed the effect of relevant environmental predictors on a diverse array of potential indicator species. We applied canonical ordination and non-parametric regression (Lowess) to classify invertebrate species responses to roads and their associated gradients. Three types of responses to road edge proximity were defined for the most common invertebrate taxa: edge-preferring or edge specialists, interior-preferring or edge-avoiders, and edge-indifferent or neutral species. Those species appearing most frequently and with higher population density between 1 and 20 m from the edge (commonly peaking at 10 m from the road) were categorized as edge-preferring. We classified taxa attaining peak population densities at or beyond 60 m from the edge (and most commonly 100 m) as interior species. Edge-neutral species were those without an evident pattern of stabilization in abundance along the gradient and with peaks in abundance at varying distance intervals. These edge litter communities contain a high native and endemic diversity but also a significant density of alien fauna. The specific patterns of penetration of road edge effects on invertebrate species should be seen as having a pervasive and cumulative impact considering the exceptionally large number of roads in these forests and the high population densities of alien invertebrates. Future management plans for forest conservation on the Canary Islands should include the highly altered but valuable litter communities along road edges.     

Participation of soil invertebrates in the organic matter decomposition in forest ecosystems of Central Siberia

The biomass of large invertebrates was studied in the soils of forest ecosystems in the forest-tundra and southern taiga of Central Siberia. Its formation is shown to be controlled by the integrated effect of the soil and climatic conditions. The distribution of the zoomass according to the main taxonomic groups testifies to the higher functional significance of the large saprophagous invertebrates in the ecosystems of the southern taiga compared to those of the forest-tundra. The quantitative contribution of the invertebrates-destroyers to the organic matter decomposition was assessed on the basis of field experiments; it was shown to be determined by the quality of the material decomposed irrespective of the conditions and time of its exposition. Every year, soil saprophages decompose 0.5–2.0% of the total phytodetritus reserves in the forest-tundra and 3–14% in the southern taiga amounting to 12–54% of its losses upon decomposition.