Insects As Conservation Targets

The most familiar forms of insect conservation are associated with campaigns to conserve individual species, often "crisis-management exercises" stimulated by perception of decline or of current or impending threats from anthropogenic changes to the environment. Many are initially local exercises, but the species may also be of national or (as regional endemics) global concern. Detection and quantification of conservation need are followed, ideally, by well-designed and effectively coordinated management or recovery plans, with adequate monitoring to determine their effectiveness. Sound biological knowledge of the species underlies any such program, and in many programs an initial research phase to elucidate key ecological features must precede optimal management. However, for this to occur, the species may need interim regulatory protection, such as a moratorium on future despoiling of its habitat.

With few exceptions, decline of insects has been difficult to quantify, because of lack of knowledge of population dynamics and absence of historical data on numbers and distribution. Many declines have been inferred from loss of habitat, on the basis of persistence in small remnant habitat patches and presumed losses elsewhere. For some well-known faunas, particularly for butterflies in western Europe, disappearances have been documented more effectively through a century or more of collector intelligence and accumulation of labeled specimens and information. The most complete example is for the British butterflies, a fauna of fewer than 60 resident species for which data are sufficient to plot reliable highresolution maps of species incidence and change over much of the past century. Such "atlases" have been produced on a 10 by 10-km2 scale and have progressively spawned similar compilations for other insect groups and countries, together with numerous recording schemes to define current situations. In North America, the annual Fourth of July Butterfly Count developed through the Xerces Society is an important initiative helping to define the template for insect conservation needs. However, for most of the tropics, which is the most species-rich part of the world for insects, such schemes are impracticable because of the lack of sufficiently informed resident entomologists/hobbyists and the complexity of the faunas, as well as vastly different local priorities.

Most concern for species, then, arises from perceived or anticipated declines to taxa considered rare or threatened in some way. For practical conservation the need is to define the severity of the threat(s), integrating this with knowledge of the species' ecology, and to determine and pursue the measures needed to alleviate the threat and either (a) prevent decline and/or loss or (b) enable recovery from decline to occur. Development of an Action Plan or Recovery Plan is often accompanied by listing the species on some form of legal or regulatory protection schedule, a step that commonly accords formal obligation to investigate and pursue conservation needs and confers priority for limited support over nonlisted species. However, listing has sometimes been seen as an end in itself, being considered as practical conservation rather than as a facilitating mechanism for practical conservation measures. Many legislations provide for eventual delisting of species as secure, and this can come about in two ways:

1. The more intensive examination of the species that results from listing it reveals that it is more secure than supposed previously, so that continued categorization as of conservation concern is not warranted.

2. Recovery (or broader management) measures are successful and render the species, and its habitat, secure.

Either outcome is positive, but the process emphasizes the need for periodic review of all listed species to determine changes in security and the effectiveness of conservation measures. The practical steps needed, as for a variety of other taxa, are varied but may include increasing habitat security, intensifying site management (for example, by enriching it with food plants and eliminating competitive weeds), increasing insect numbers and distribution through ex situ measures such as captive breeding and release, and translocations to sites within the historical range from strong donor colonies. Any such program should be monitored fully and coordinated and managed effectively by a species recovery team whose membership includes informed entomologists. Because of the novelty of insect species management in this way, many such teams still tend to focus on expertise derived from vertebrates rather than reflect invertebrate expertise strongly.

In addition to species focus, assemblages or communities of insects are sometimes adopted as conservation targets, leading to a larger scale of consideration.

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