Approaches to Terrestrial Invertebrate Conservation
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224 Endangered Terrestrial Invertebrates Papilionoidea butterflies are being evaluated); the results are then used to interpolate the general trends within populations of all its members There appears to be, however, a number of biases in conservation assessment efforts for terrestrial invertebrate taxa, which may give a false picture of species distribution and abundance (Cardoso et al., 2001) For example, species tend to be monitored more in places where high species richness is to be expected The selection of taxa being monitored or evaluated is strongly skewed toward ‘‘charismatic’’ and easily identifiable groups, such as butterflies, but these groups are typically species-poor and may not be representative of invertebrates as a whole There is also a tendency to overestimate the overall species’ rarity based on regional occurrence, which often falls on the margins of the species’ range The Convention on International Trade in Endangered Species (CITES) is a multilateral treaty designed to ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species in the wild, and it accords varying degrees of protection to more than 33,000 species of animals and plants It currently lists 348 species of terrestrial invertebrates, albeit there is little correspondence between the CITES list, which has executive power to control the international trade in these organisms, and the IUCN Red List, which ranks species according to relatively rigorous criteria of current or potential threat For example, of the 23 species of spiders listed by CITES, only one appears on the IUCN Red List (categorized as Lower Risk); conversely, of the 25 species of spiders listed as threatened by the IUCN, none is listed by CITES Approaches to Terrestrial Invertebrate Conservation Coarse and Fine Filters in Invertebrate Conservation The concept of conserving entire plant and animal communities in reserves was originally viewed as an efficient coarse filter approach to conserving biodiversity that would protect 85–90% of all species This was based on the assumption that carefully selected areas, often containing socalled ‘‘umbrella species’’, will preserve enough habitat heterogeneity to sustain a large selection of unrelated taxa More recently, the coarse filter has evolved to a concept of conserving species diversity by providing adequate representation (distribution and abundance) of ecological land units based on an understanding of their natural disturbance regimes This coarse filter approach does not necessarily prescribe reserves but rather recognizes ecological processes and provides for a dynamic distribution of ecological units across the landscape over time (Samways, 2005) The reality of a matrix of agricultural landscapes and high fragmentation of the remaining natural habitats across most of Europe and many other developed areas makes it necessary to develop conservation strategies that focus on management and restoration of what remains In the UK, landscape-scale conservation projects are now the main delivery mechanism to conserve its threatened Lepidoptera It is achieved by providing advice to landowners and assistance with obtaining agri-environment or woodland grant schemes, and by habitat management under the guidance of the UK’s Butterfly Conservation organization (Ellis et al., 2011) The complementary fine filter approach focuses on conserving individual rare or specialized species that slip through the coarse filter and are not necessarily protected in reserves The Red List assessments are designed to pinpoint such species, and its fine filter assessments are conducted to evaluate whether sufficient amount and distribution of habitat is provided under the coarse filter strategy The creation in 1978 of the Tripuı´ Reserve in Minas Gerais province of Brazil to protect the population of a velvet worm (Peripatus acacioi) is an example of a conservation action based on a fine filter assessment of the status of a single species Surrogates in Terrestrial Invertebrate Conservation Plants have long been used as environmental surrogates for invertebrate diversity, particularly that of insects Because they are easier to identify and map than invertebrates, and there is an unquestionable dependence of most insects on their existence, species-rich plant communities can be used to designate protected areas with expectedly high levels of invertebrate diversity It has been shown that species richness of even those invertebrates that not directly rely on any particular plant species, such as dragonflies, is positively correlated with plant diversity Plants have also been demonstrated to be much better predictors of invertebrate diversity than vertebrates At the same time, there exist confounding issues, and spatial distribution of insects does not necessarily overlap completely with that of plants; for example, although there is a strong relationship between the distribution of butterflies and leafhoppers, and that of tallgrass prairie plants, no such correlation was found between other prairie plants and other insects This suggests that focus on ‘‘hotspots’’ of plant diversity may not include many insect species at finer scales Plant surrogacy approaches usually emphasize indigenous vegetation, but in the absence of that, even exotic plants may provide suitable habitats for native invertebrate faunas: in the Azores exotic forests have provided alternative habitats suitable for native saproxylic beetles, whereas in South Africa pine plantations turned out to provide sufficient habitats for velvet worms (Opisthopatus cinctipes) that used to inhabit indigenous, but now largely gone coastal forests (Hamer et al., 1997) Also in South Africa, organic vineyards have the potential to make an important contribution to arthropod conservation in the Cape Floristic Region at the field scale, although at landscape scale, the preservation of natural fragments in the vineyard landscape is the most effective measure to increase biodiversity Animals, and birds in particular, have been used as surrogates for invertebrate distribution and richness At some spatial scale, birds and butterflies show similar trends in species richness and diversity In Uganda, the selection of potential forest reserve sites based on either birds or butterflies was as effective at representing other taxa as the selection based on the richness of plants and a wide range of animal taxa In the Azores species richness of four groups of endemic arthropods was a good predictor of overall species richness (Borges et al., 2010), but in other parts of the world vertebrate or