Extinction behind our backs: the possible fate of one of the Darwin’s finch species on Isla Floreana, Galápagos

Without regular monitoring a rare species may slip into extinction unnoticed. We report a possible case from the Galápagos archipelago. The warbler finch (Certhidea fusca) has not been recorded by scientists on Isla Floreana in recent years, and we have been concerned about its status. On a two-day visit to prime habitat in the breeding season of 2004 we used playback of warbler finch song and calls recorded on another island to stimulate an approach of local birds. We failed to find a single warbler finch, whereas we encountered numerous small tree finches (Camarhynchus parvulus), medium tree finches (C. pauper) and yellow warblers (Dendroica petechia). Searches in 1979, 1983, 1997 and 1999 were also unsuccessful. Our continuing failure to find any warbler finches indicates the species must be extremely rare on the island, if not actually extinct. We discuss possible reasons for their demise and draw attention to other species that could be heading in the same direction.     

The Lazarus effect: can the dynamics of extinct species lists tell us anything about the status of biodiversity?

Lists of extinct Australian plants created over the last 20 years were examined and were shown to have high levels of turnover. In general, the lists are contracting in length and their composition changes substantially, a phenomenon we term the ‘Lazarus effect’. There is little explanation for these changes in the cryptic nature of species habits, or their distribution in remote locations. Most of the turnover is due to changes in knowledge about the species' status, and changes in taxonomy. Lists maintained in some other countries are more stable, but at the potential cost of underestimating the extent of extinction. Comparisons between jurisdictions and between lists are difficult because of different attitudes taken towards uncertainty and variation in research effort among different taxa. For any assessment that uses lists of extinct or threatened species as indicators of environmental change, we recommend that sources of bias are reduced and that uncertainties in lists are made more transparent. An important step in this process is to distinguish listing changes due to a change in status from those due to a change in knowledge about distribution, abundance and taxonomy. Assessments of environmental change based on species lists should be standardised to exclude these latter sources of variation, and take into account new assessments of previously unevaluated taxa.     

Rapid decline of California’s native inland fishes: A status assessment

A quantitative protocol was developed to determine conservation status of all 129 freshwater fishes native to California. Seven (5%) were extinct; 33 (26%) were found to be in danger of extinction in the near future (endangered); 33 (26%) were rated as sufficiently threatened to be on a trajectory towards extinction if present trends continue (vulnerable); 34 (26%) were rated as declining species but not in immediate danger of extinction. Only 22 (17%) species were found to be of least concern. Of 31 species officially listed under federal and state endangered species acts (ESAs), 17 (55%) were rated as endangered by our criteria, while 12 (39%) were rated vulnerable. Conversely, of the 33 species that received our endangered rating, only 17 (51%) were officially listed under the ESAs. Among the seven metrics used to assess extinction threat, climate change, area occupied and anthropogenic threats had the largest negative impacts on status. Of 15 categories of causes of decline, those most likely to diminish status were alien species, agriculture, and dams. Overall, 83% of California’s freshwater fishes are extinct or at risk of becoming so, a 16% increase since 1995 and a 21% increase since 1989. The rapid decline of California’s inland fishes is probably typical of declines in other regions that are less well documented, indicating a strong need for improved conservation of freshwater ecosystems.     

Status and distribution of stipitate hydnoid fungi in Scottish coniferous forests

Stipitate hydnoid fungi (specifically members of the genera Bankera, Hydnellum, Phellodon, Sarcodon) have become the focus of increasing conservation concern, particularly following the detection of widespread declines in abundance. To assess their status in Scotland, 103 field surveys were undertaken, including searches of 50 of the 77 native pinewood sites, traversing a total of 902 km. Hydnoid fungi were encountered on 30 of the searches (29%), primarily in eastern regions of Scotland. A maximum of 8 species was recorded on a single search, 11 species being encountered in total. Of 22 plantation sites surveyed, 11 were found to contain populations of hydnoid fungi. Four species were relatively widespread, both in native woodlands and plantations: Bankera fuligineoalba, Hydnellum peckii, Phellodon tomentosum, and Sarcodon imbricatus. All species tended to be associated with particular microsites, especially riverbanks, tracksides or areas of exposed mineral soil; median values for percentage bare ground cover surrounding each sporome were generally above 50%. Median values for diameter at breast height (dbh) of associated trees were in the range 20-50 cm for all species. Data from the field surveys were pooled with previous records to assess the number of hydnoid species recorded for each native pine woodland. When examined by regression, a positive relationship was recorded between the number of species and woodland area (r²=0.69, P<0.001, n=50). To assess the occurrence of declines, the number of 10 km gridsquares for each species was compared using records made pre- and post-1970. These data provided evidence for declines in only four of the 17 species considered. However, 12 species are threatened with extinction according to the IUCN Red List criteria, owing to their restricted patterns of distribution. The implications of these results for the conservation of hydnoid fungi in Scotland are discussed.     

Using the scaling behaviour of higher taxa for the assessment of species richness

In this paper, we show that fine-scale data on seed plant diversity exhibit exponential scaling behaviour across the taxonomic hierarchy. One practical implication of this result is that the scaling behaviour of higher taxonomic levels can be used to predict species richness in a given area with reasonable accuracy.     

Risk assessment: Simultaneously prioritizing the control of invasive plant species and the conservation of rare plant species

Although the consequences of the homogenization of Earth’s flora and fauna are not well understood, experts agree that biological invasions pose hazards to rare species. As a result, there is a need for a systematic approach to assess risks from invasive species. The Relative Risk Model can be adapted to assess combinations of rare species, invasive species, and regions. It also can be applied to different taxonomic groups and at different spatial scales. This flexibility makes it a promising tool for invasive species risk assessment. We used the Relative Risk Model to quantify risks posed to endangered plant species by non-indigenous invasive plant species in Nebraska.We modeled the suitable habitats for eight invasive plant species, which we subsequently compared to documented occurrences of endangered plant species in a Geographic Information System. We combined this data with an assessment of the ecological impacts of each invasive species in a regional risk assessment framework to simultaneously calculate relative risk scores for invasive plant species, imperiled plant species, and subregions. We assessed uncertainty with Monte Carlo simulations.The results of this assessment are discrete values indicating the relative threat posed by invasive species to rare species, the relative risk posed to the rare species, and the relative risk in subregions. Results indicate that the invasive species Elaeagnus angustifolia and Rhamnus cathartica pose the greatest risks to endangered plants in Nebraska. The rare species Panax quinquefolius and the subregion Western Corn Belt Plains show the highest risk scores.     

Translocations of eight species of burrow-nesting seabirds (genera Pterodroma, Pelecanoides, Pachyptila and Puffinus: Family Procellariidae)

Development of seabird translocation techniques is required to meet species recovery objectives, to improve conservation status, and to restore ecological processes. During 1997-2008 we undertook translocation trials on eight petrel species of four genera within the New Zealand region: common diving petrel (Pelecanoides urinatrix), fairy prion (Pachyptila turtur), grey-faced petrel (Pterodroma macroptera gouldi), Pycroft’s petrel (Pterodroma pycrofti), Chatham petrel (Pterodroma axillaris), Chatham Island taiko (Magenta petrel; Pterodroma magentae), fluttering shearwater (Puffinus gavia), and Hutton’s shearwater (Puffinus huttoni). A total of 1791 chicks within 5 weeks of fledging were moved up to 240 km, placed in artificial burrows and hand-fed until they fledged. Of these, 1546 fledged, and so far at least 68 have returned as adults to the translocation sites. Most birds were crop-fed a puree based on tinned sardines and fresh water. This diet worked well for all species regardless of their typical natural diet (planktonic crustaceans, squid, or fish) with all species fledging above or close to mean natural fledging weights.     

Survey of New Zealand Department of Conservation staff involved in the management and recovery of threatened species

In terms of managing biodiversity, a third of the land area of New Zealand is included in a conservation estate of national parks, reserves and sanctuaries. Administration of this large natural heritage asset is by 13 separate Department of Conservation (DOC) conservancies. A survey was conducted, across all conservancies, of DOC staff directly involved with the management and recovery of threatened New Zealand species. The aim of the survey was to gain an insight into how DOC staff regard the management tools available to them for the recovery of threatened species. The survey also assessed the perceived relevance of the threatened species recovery plans (TSRPs) currently in use by these staff. The results of the survey show that in general, the DOC staff consider that a lack of adequate funding, poor communication between conservancies and staff shortages have resulted in failure to achieve comprehensive management and recovery of threatened species. There was an expectation for TSRPs to comprehensively guide management and recovery actions but most staff concluded that TSRPs failed to meet this objective. It was identified that TSRPs need to be kept up-to-date and preferably in an electronic format accessible to all DOC staff throughout New Zealand. There was strong support for the establishment of a national approach for the recovery of threatened species. Concern was expressed that current resourcing only allowed recovery of a very small number of New Zealand’s threatened species with staff calling for secure funding for the duration of threatened species recovery programmes.     

Grouping and prioritization of vascular plant species for conservation: combining natural rarity and management need

National and International Red Lists and Legal Acts specify species with conservation needs, mainly on the basis of personal experiences. For effective conservation we need scientifically justified prioritization and grouping of these species. We propose a new combined approach where species are grouped according to the similar activities needed for their conservation. We used the national list of vascular plant species with conservation need for Estonia (301 species), and linked these species to eight qualitative conservation characteristics, four reflecting natural causes of rarity (restricted global distribution; restricted local distribution within a country; always small populations; very rare habitat type), and four connected with nature management (species needing the management of semi-natural grasslands; species needing local disturbances like forest fires; species needing traditional extensive agriculture; species which may be threatened by collecting). Only one positive association occurred among the characteristics - between restricted local distribution and small size of populations. Thus, natural causes of rarity and management aspects are not overlapping, and both should be used in conservation activities. Species grouping by different conservation characteristics allows one to focus on species groups with similar conservation needs instead of individual species. Prioritization of species with conservation needs can be based on the number of conservation characteristics that are associated with a particular species. Our prioritization did not correlate with the categories of the national Red Data Book, but a positive association was found with legal protection categories. The legislation, however, covers only the natural causes of rarity. We propose a new combined approach for plant species’ conservation planning that starts by considering human induced rarity and progresses through to natural rarity causes.     

Storm-generated fragments of the seagrass Posidonia oceanica from beach wrack – A potential source of transplants for restoration

The use of fragments detached naturally from Posidonia oceanica, a threatened seagrass protected by European legislation, as non-destructive alternative to removing cuttings from donor meadows for restoration efforts has been recently proposed. A 4-year study was performed to investigate whether storm-generated fragments deposited on beaches can be salvaged and used as transplant source. Specifically, we examined in outdoor tanks (i) how long fragments survive after detachment from parents, (ii) whether fragment survival and regeneration ability are influenced by morphological characteristics, i.e., initial fragment growth form and size, and (iii) whether a single fragment can be divided artificially to obtain more transplants. Finally, we monitored the first year survival of fragments lodged between rubbles of a submersed artificial reef 3 years after storage in tanks to test for their capacity to re-establish in the field. Four months after collection, fragment survival was high (80–96%). Half of the fragments regenerated and survived as long as 3 years in tanks. Initial growth form and size were not predictors of fragment survival or regeneration probability. Division of fragments allowed doubling transplant number. One year after transplanting, 50% of the fragments on the artificial reef were still present and ca. half of them produced new shoots. This indicates that fragments retain the capacity to re-establish once reintroduced into the field and thus could represent a potentially important transplant source. The use of this material could have major advantages over traditional restoration techniques, including large availability with zero impact on existing populations and low collection efforts.     

Modelling bryophyte distribution based on ecological information for extent of occurrence assessment

For some groups such as bryophytes, the IUCN distribution criteria are of critical importance to evaluate threat status, since other parameters cannot be determined readily. In this study, we propose the use of ecological niche modelling methods to estimate the extent of occurrence (EOO) of species. Herbarium (LISU) collection data are used to estimate the potential distribution of bryophytes based on three different methods: GARP, MAXENT and ENFA. The records of bibliographic references were projected against model predictions, and used for validation purposes using the receiver operating characteristic (ROC) method, as well as knowledge about ecological and geographic affinities.Four species (Antitrichia californica, Riccia sommieri, Cryphaea heteromalla and Racomitrium hespericum) were chosen as case studies; they were selected to represent taxa with contrasting ecological requirements, biogeographic importance and conservation value. The main difference between the two approaches (topological and ecological) for determining EOO is that the former only consider species distribution in space, whereas ecological methods may include both spatial distribution as well as environmental ranges. The methodological advance presented here explores the links between population distribution and environmental data, filling the gaps between distribution and administrative borders.     

Odonata enter the biodiversity crisis debate: The first global assessment of an insect group

The status and trends of global biodiversity are often measured with a bias towards datasets limited to terrestrial vertebrates. The first global assessment of an insect order (Odonata) provides new context to the ongoing discussion of current biodiversity loss. A randomly selected sample of 1500 (26.4%) of the 5680 described dragonflies and damselflies was assessed using IUCN’s Red List criteria. Distribution maps for each species were created and species were assigned to habitat types. These data were analysed in respect to threat level for regions and habitat types. We have found that one in 10 species of dragonflies and damselflies is threatened with extinction. This threat level is among the lowest of groups that have been assessed to date, suggesting that previous estimates of extinction risk for insects might be misleading. However, Odonata only comprise a small invertebrate order, with above-average dispersal ability and relatively wide distribution ranges. For conservation science and policy to be truly representative of global biodiversity a representative cross-section of invertebrates needs to be included.     

Research effort allocation and the conservation of restricted-range island bird species

Knowledge gap analyses can be useful to highlight imbalances in research and to improve the distribution of conservation research efforts. We used ISI’s Web of Knowledge (WoK) and BirdLife International’s library catalogue (BLI) to examine the allocation of research effort amongst the extinction-prone island restricted-range birds (RRSs, n = 1321) and the island endemic bird areas and secondary areas (EBAs, n = 108; SAs, n = 58) previously identified by BirdLife International. We found that the distribution of research effort was very uneven across both species and areas. Half of the number of outputs obtained from WoK referred to 3.1% of the island restricted-range bird species and to 4.8% of the endemic bird areas and secondary areas, whereas 52.2% of the species and 34.3% of the areas had no output. The global distribution of research had a strong spatial component, with a limited number of places receiving most of the research efforts (Hawaii, New Zealand, Central America), while many species rich areas were very poorly studied (South East Asia, South Pacific, most Atlantic islands). Research amongst the most threatened RRSs tended to be less biased, with these species having a higher probability of having at least one output from WoK than less threatened species. Given that threats to the conservation of biodiversity are often highly context-dependent, we advocate prioriting the study of poorly known species and regions. Finally, we integrate the knowledge gaps we identify with previously established conservation priorities, in order to prioritize for future conservation research on RRS, EBAs and SAs.     

Using remote sensing to inform conservation status assessment: Estimates of recent deforestation rates on New Britain and the impacts upon endemic birds

Remote sensing is increasingly used by policy-makers and conservationists to identify conservation priorities and changes in land cover. This is particularly important in the biodiverse tropics, where there are often few field data. Conservation action is often directed towards areas containing globally threatened species, but there have been few attempts to improve assessments of species’ extinction risk through remote sensing. Here, in a novel approach we use deforestation estimates, measured through satellite imagery, to assess the conservation status of an entire endemic avifauna, based on IUCN Red List criteria. The island of New Britain, east of New Guinea, is of very high global conservation importance, and home to 37 endemic or restricted-range bird species. Analysis suggests 12% of forest cover was lost between 1989 and 2000, including over 20% of forest under 100 m altitude, with substantial areas cleared for commercial oil palm plantations. Application of the IUCN Red List criteria to these new data on area of remaining forest and rates of deforestation indicates that many species are more threatened than previously realised, with the total number of threatened or near threatened species increasing from 12 to 21. Thus, this study highlights the urgency of establishing and effectively managing protected areas in suitable lowland forests of New Britain. More broadly, it demonstrates another potential of remote sensing to assist strategic conservation decisions.     

Planning low-impact tourist paths within a Site of Community Importance through the optimisation of biological and logistic criteria

A leading goal in the management of protected areas is to promote a balanced coexistence between wildlife and people. Although this target may be achieved by limiting human activities through buffer zones and restricted areas, a more rigorous approach can be based on optimisation models founded on quantitative and transparent scientific methodologies.

In this paper, a decision model is proposed, for the first time, for planning low-impact tourist paths within a European Union Site of Community Importance. The proposed methodology seeks to plan optimised paths based on a virtual landscape built on both biological and logistic criteria. Our model consists of four steps: (1) choice of biological and logistic constraints; (2) selection of biological and logistic factors; (3) use of fuzzy scoring to standardise and weight criteria and (4) application of least-cost modelling to the virtual landscape resulting from previous steps.

We identified three optimised routes for new tourist paths which have the least possible impact on existing biodiversity (habitats, plant and animal species), meeting logistic criteria as well. The proposed approach also allows the impacts of suggested paths to be estimated quantitatively thereby allowing comparison with existent paths. Proposed paths, based on optimisation, perform considerably well; furthermore, we were able to propose the decommissioning of eight existing paths that have high impacts on biodiversity.

This work not only proposes a framework for planning low-impact tourist paths within protected areas, but also purports the idea that, through the use of proper optimisation models, a satisfactory balance between nature and human activities is achievable.     

Concerns regarding the scientific evidence informing impact risk assessment and management recommendations for invasive birds

Invasive species can be a major threat to biodiversity and economy. Given the large number of introduced invasive species and the limited resources available, a rigorous assessment of the potential impact of these species is of vital importance for prioritizing management programs. Often, general scoring systems in which certain criteria are used to assess the impact of an invader along several impact categories are applied to obtain a ranking of troublesome invaders. Likewise, Kumschick and Nentwig (2010) provided a first categorization of invasive bird impacts in Europe, and argued that several invasive birds should be eradicated because of the threat they pose to biodiversity.This is surprising, as recent reviews suggest that there is little evidence that invasive birds strongly impact biodiversity. We therefore re-evaluated this risk assessment. We found that in the majority of cases, the evidence presented to support impact claims is weak, as they are generally not based on direct scientific research but on often anecdotal observations relating to small areas only. Moreover, even if all claims would materialize, this does not necessarily justify a call for eradication. Previous experiences with eradications have learnt that a feasibility study, encompassing all aspects of biological invasions (including public opinion and possible benefits of the invader) is critical for the achievement of any strategy against invasive species. This is essential, as ill-conceived calls for eradication could result in a public backlash, causing funding agencies and managers to shy away from the problems posed by invasive species.     

Large-scale estimators of threatened freshwater catchment species relative to practical conservation management

Freshwater ecosystems are among the most threatened in the world. In light of the threats to freshwater biodiversity, it is essential to map the distribution and status of species to ascertain their threat status for prioritizing conservation action. However, while there is agreement that the conservation of freshwater ecosystems depends on whole-catchment management, there are still a wide variety of large-scale mapping methods in use, the advantages and disadvantages of which have not been fully explored. This study shows that area estimation based on minimum convex polygons should not be encouraged for aquatic species. The IUCN definition of area of occupancy (AOO) is a useful term, albeit highly scale-dependent, for assessment of the total approximate area over which a species occurs. However, for aquatic fauna, and perhaps many other organisms, assessment of occurrence should be based on the more accurate point-locality presences only. The IUCN extent of occurrence (EOO), for freshwater catchment species, should be redefined as ‘the sum of the smallest hydrological units identified, of presently known, inferred or projected occurrences of a taxon, excluding cases of vagrancy, that are used to estimate the threat to a taxon’. A single hydrological unit is also the conservation or management unit. Here we suggest that this unit is the quaternary catchment. This new mapping approach is more appropriate and practical for use in both management planning and conservation action. We suggest that conservation managers and decision makers facilitate co-operation in freshwater mapping efforts by working at the same spatial scale, i.e. the same hydrological unit.     

Inferring extinction from biological records: Were we too quick to write off Miss Waldron’s Red Colobus Monkey (Piliocolobus badius waldronae)?

We are now entering a time of immense environmental upheaval where experts are increasingly required to provide conservation assessments. Quantitative assessment of trends in species’ range and abundance is costly, requiring extensive field studies over a long period of time. For many species in dense habitats, it may be very difficult to establish reliable and sensitive survey and monitoring techniques, which are able to warn of potentially catastrophic population declines. Unfortunately many other species are only known through a few ‘chance’ sightings or a handful of museum specimens and therefore extinction may be even harder to ascertain. In 2000 Miss Waldron’s Red Colobus, Piliocolobus badius waldronae, was reported as extinct, but since then (in 2001) a single specimen has been collected. Four probabilistic methods were used to infer extinction based on a record of sightings of the subspecies. Based on the date when the extinction statement of Miss Waldron’s Red Colobus was made, all four methods returned probability values >0.05, suggesting that the subspecies is extant, but is extremely rare. If we cannot successfully monitor populations of critically endangered taxa, it becomes almost impossible to predict their extinction with any certainty and we can expect increasing numbers of false alarms in future years, which may undermine the potential for conservation action and, more worryingly, public support for conservation.