bs_bs_banner
Austral Entomology (2018) 57, 173–181
Review Threatened species conservation of invertebrates in Australia: an overview Michael F Braby1,2* 1
Division of Ecology and Evolution, Research School of Biology, The Australian National University, Acton ACT 2601, Australia. 2 Australian National Insect Collection, GPO Box 1700, Canberra ACT 2601, Australia.
Abstract
Invertebrates make up about 80% of all species, yet they rarely attract conservation attention compared to the more ‘charismatic’ vertebrates such as birds and mammals. Threatened species conservation, a field of conservation biology in which individual species are targeted for protection and conservation management, complements the landscape approach to biodiversity conservation and could be used more effectively to promote the plight of threatened or imperilled invertebrates given the global biodiversity crisis and estimated rates of anthropogenic species extinction. In this overview, steps in the species-oriented conservation process are outlined, including conservation status evaluation, listing under legislation, preparation of Action and Recovery Plans, recovery actions, recovery teams and monitoring, in order to prevent extinction or minimise risk of extinction. The process is not without its challenges, but it does provide valuable information that is not always obtainable with the protection and management of threatened ecological communities and habitats. However, to be most effective, a more strategic approach to listing species is required. It is recommended that more national Action Plans, either of higher taxonomic groups or of ‘indicator’ species – suites of species indicative of threatened ecological communities, habitats, biomes, key threatening processes, co-dependent threatened host species or short-range endemics – are needed. These plans would provide a national overview of threatened and imperilled invertebrates in conservation need that is far more comprehensive than presently available. A detailed national list of threatened invertebrate species could then be promoted (and nominated for listing under the EPBC Act) for greater conservation advocacy.
Key words
Action Plan, conservation status evaluation, Environmental Protection and Biodiversity Conservation Act, IUCN Red List categories and criteria, monitoring, recovery action, Recovery Plan, recovery team.
IN TR ODUCTION Invertebrates make up approximately 80% of all species (Cardoso et al. 2011b; Mora et al. 2011; Stork et al. 2015; but see Larsen et al. 2017 for an alternative estimate of the pie of life), yet they rarely attract conservation attention compared to the more ‘charismatic’ vertebrates such as birds and mammals. There are several reasons why insects and allied organisms fare so poorly in the biodiversity conservation arena (Yen & Butcher 1997; New 2009; Cardoso et al. 2011b). First, most invertebrates (apart from butterflies, dragonflies, some beetles, giant silk moths and bees) have a poor public image, with a general lack of sympathy and understanding of their importance in ecological processes and ecosystem functioning (the public dilemma). Second, their diversity is overwhelming, with a general lack of information on taxonomic identity (the Linnaean shortfall) and geographical distribution (the Wallacean shortfall). Third, there is a general lack of understanding of conservation need among policy makers (the political dilemma). Fourth, conservation resources are miniscule compared with funds allocated to vertebrates, both in terms of total expenditure invested and average expenditure per species (Cardoso et al. 2011b). Fifth, there are very few invertebrate conservation biologists, and few entomol*
[email protected] © 2018 Australian Entomological Society
ogists raise their concerns when species, ecological communities or habitats are under threat (the advocacy dilemma). There are two broad complementary approaches to invertebrate conservation (New 1984, 2009; Yen & Butcher 1997; Samways 2005, 2007). One is the ‘fine filter’ approach in which the focus is on the conservation management of individual threatened species, similar to that adopted for the better-known groups such as birds and mammals. The other is the ‘coarse filter’ approach that essentially aims to conserve representative samples of habitats or biotypes within broad landscapes, such as through the National Reserve System or through the protection of biodiversity hotspots – restricted areas with exceptionally high levels of endemism but facing a substantial degree of threat. This approach may include recognition and protection of insect assemblages or threatened ecological communities. Another landscape approach is to identify geographical areas with restricted concentrations of evolutionary diversity according to the combined extent of phylogenetic diversity and weighted endemism (Rosauer et al. 2009). Termed phylogenetic endemism, this novel approach applies a concept of endemism based on lineages, rather than species, but so far it has received little attention from an invertebrate perspective (Garrick 2011). The first approach of targeting individual threatened species of insects (and of other invertebrates) for protection and conservation management has a number of challenges that set them doi: 10.1111/aen.12324
174
M F Braby
apart from vertebrates and vascular plants (New 2009). For instance, most species are small in size and thus often unnoticed, occupy specialised habitats, have small world distributions (narrow-range endemics) where they may be restricted to particular sites or microhabitats, and frequently form complex population structures across the landscape (metapopulations). They may have short generation times with pronounced seasonality or are highly irregular in incidence (with protracted life cycles lasting for years but adults appearing for only brief periods) so that targeted surveys and monitoring may be limited to a narrow window, which could be highly unpredictable among years (Sands & New 2008). Despite these limitations, species-oriented conservation of insects and other invertebrates threatened with extinction is worthwhile given the global biodiversity crisis and estimated rates of anthropogenic species extinction (possibly as high as c. 3000 species/year) (New 1993; Thomas et al. 2004; Cardoso et al. 2011a). Threatened species conservation involves several steps (New et al. 1995; New & Yen 1995; New 2007, 2009, 2011). The six main steps involved are: (1) evaluating the status of the species of conservation concern; (2) listing the species formally under national and/or State/Territory legislation, which usually involves recognition that the taxa are threatened according to various criteria; (3) preparing an Action Plan and/or a Recovery Plan in which the conservation status may be formally re-evaluated, patterns of decline summarised and key threatening processes attributing to that decline are identified and clarified; (4) providing a set of recommendations (recovery actions and management options) on how best to mitigate threats; (5) implementing those management actions through a recovery team; and (6) monitoring recovery actions to ensure that management is working and the risk of extinction is prevented or minimised (Fig. 1). In this overview, steps in the threatened species conservation process are outlined. The process is not without its challenges, but it does provide important information that is not always obtainable with the protection and management of threatened ecological communities and habitats. However, for threatened species conservation to be most effective, a more strategic approach to listing species is required. It is suggested that more national Action Plans, and the concomitant listing under Commonwealth legislation, is required, which would provide a national overview of threatened and imperilled invertebrates in conservation need that is far more comprehensive than is presently available.
C O N SE R V A T I O N S TA T U S Accurate evaluation of the conservation status of threatened species is a critical part of threatened species conservation. The Australian Commonwealth Environmental Protection and Biodiversity Conservation 1999 Act (EPBC Act) closely follows the International Union for the Conservation of Nature (IUCN) Red List categories and criteria (IUCN 2001). The IUCN Red List categories and criteria were developed primarily to establish a scientifically rigorous approach to determine risks of extinction and improve objectivity and transparency in assessing the © 2018 Australian Entomological Society
Fig. 1. Sequence of steps in threatened species conservation management. Conservation status is usually assessed before listing and then may be re-evaluated after listing through preparation of an Action Plan. Alternatively, taxa may be listed after the publication of an Action Plan in which the conservation status is evaluated, and those species identified as threatened are then proposed for nomination. Monitoring may indicate that refinement of recovery actions is required, particularly if management is failing, or it may indicate that where recovery is successful the species be categorised as Conservation Dependent because it requires conservation management to mitigate threats or de-listing is recommended because ongoing management is no longer required.
conservation status of threatened species globally (IUCN 2017). Thus, the IUCN Red List categories and criteria are widely recognised as the most comprehensive, objective standard for evaluating the conservation status of all plants and animals. The EPBC Act currently recognises six categories for ranking species according to their extinction or extinction risk: Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU) and Conservation Dependent. The Conservation Dependent category is for taxa that would be eligible for listing as threatened were it not for the operation of a designated ongoing management program. However, while the EPBC Act assessment generally follows IUCN practice, curiously it has no Near Threatened (NT) category or Data Deficient (DD) category, and it does not include criterion D2 (restricted area of occupancy and under threat) – this deficiency may be particularly concerning for short-range endemic invertebrates (Harvey 2002), although this is being rectified under the Common Assessment Method (C. Palmer, pers. comm. 2017). The Common Assessment Method is a standard approach recently proposed by the Australian Government and all States and Territories in Australia for evaluating the conservation status and listing of threatened species across all jurisdictions
Threatened species conservation (Commonwealth Department of the Environment and Energy 2017a). If approved, species under this method will be assessed at the national level using IUCN Red List criteria so that, within each relevant jurisdiction, species are listed in the same category, leading to better alignment of threatened species listings between State and Territory lists and the national list. Species may still be listed by the relevant jurisdictions as a State or Territory threatened species, but such species are not regarded threatened nationally and will not be included in the EPBC Act list of threatened species. Although the IUCN Red List criteria are designed for global taxon assessment of conservation status across all life forms (Rodrigues et al. 2006), there has been some criticism of their utility for invertebrates (Sands & New 2002; New & Sands 2003; New 2009; Cardoso et al. 2011a). The main concern is that there is frequently insufficient information on the various parameters required for adequate assessment, such as decline in abundance or distribution. Indeed, this lack of information is perhaps one of the greatest impediments to invertebrate conservation – inadequate data and lack of evidence are the norm (Yen & Butcher 1997; Cardoso et al. 2011b; New et al. 2012). Indeed, Yen and Butcher (1997) suggested that single species conservation of invertebrates be reserved only for a few flagship species because of this general lack of information, which has several dimensions (Cardoso et al. 2011b). First, there is the taxonomic impediment – of an estimated species diversity of 320 500 Australian invertebrates, only 98 700 (c. 30%) have been described (Yeates et al. 2003; Chapman 2009). In other words, most species of invertebrates (c. 70%) are not described, catalogued or diagnosed or are yet to be discovered. Second, the spatial distributions and geographical ranges of most species are poorly known. Third, changes in abundance of populations in space and time are generally unknown. Fourth, the natural history and basic knowledge on ecology and biology, including critical habitats, are usually unknown for most species. The IUCN has recognised that lack of information is a problem in status evaluation and includes the Data Deficient (DD) category in their Red List Categories (IUCN 2001; IUCN Standards and Petitions Subcommittee 2016). A taxon is listed as Data Deficient when there is inadequate information on which to make a sound assessment of its risk of extinction based on its population status and/or distribution. However, because the Data Deficient category is not a category of threat, IUCN emphasises that assessors must use all available information when making an evaluation and place taxa into Data Deficient only when there is no alternative. Of course, taxa assessed as Data Deficient may be of conservation concern and at risk of extinction, but more information is required. That is, they may qualify as Near Threatened (NT) or for a threatened category (Vulnerable, Endangered or Critically Endangered) once adequate data are available. Bland et al. (2017) have recommended that for Data Deficient taxa, justification tags be assigned for each to identify knowledge gaps and help prioritise re-assessments. For example, lack of information could arise because there are few records, historical records only, uncertainty in locations or distribution, uncertain threats or taxonomic uncertainty, or uncertainty in abundance and how populations change in space and time (e.g.
175
for species with boom and bust life history strategies). To improve spatial data for Data Deficient species of conservation interest, New et al. (2012) advocated the need for more systematic surveys, either of individual taxa or of assemblages of invertebrates, for example, in protected areas for which inventories are usually very poorly documented. It should be emphasised that only one of the five IUCN Red List criteria (A, B, C, D or E) needs to be met for a taxon to be listed for a threatened category (see Table 2.1 in IUCN Standards and Petitions Subcommittee 2016 for definitions of criteria). Criteria B1, B2 and D2 are the most relevant for invertebrates, especially criterion B, because of the difficulty of obtaining reliable data on changes in relative abundance for criteria A, C, D1 and E (see also New 2009; Cardoso et al. 2011a; New et al. 2012). Criterion B is concerned with small geographic range size, in the form of B1ab(iii) or B2ab(iii) (extent of occurrence (EOO) or area of occupancy (AOO) and locations few/severely fragmented and continuing decline (observed, estimated, inferred or projected) in area, extent and/or quality of habitat), whereas criterion D2 deals with short-range endemics (restricted AOO (typically
