ISSN:1052-7613    

DOI:10.1002/aqc.3270030402

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.For the first time in 1973, the Endangered Species Act allowed for the listing and conservation of insects that might be in danger of extinction. The Act, as it pertains to insects, is administered by the US Fish and Wildlife Service.2.Only one aquatic insect,Ambrysus amargosus(Naucoridae), is listed under the Act's provisions, but 142 species are candidates for future listing rules.3.Entomologists who study aquatic insects have an opportunity to cooperate with state and federal biologists in providing data, carrying out contracted surveys, and promoting conservation action to protect aquatic species in need of conservation.

ISSN:1052-7613    

DOI:10.1002/aqc.3270030403

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.The Ephemeroptera, Plecoptera and Trichoptera (EPT; mayfly, stonefly and caddisfly, respectively) faunas of the southern Appalachian Mountains are rich in species, including many endemic species. The species richness is a result of unique geological, climatological, and hydrological features of the region.2.Humans have impacted, and are impacting, the stream faunas in several significant ways, primarily through air pollution (with acid precipitation), introduction of exotic forest pests, impoundments (ponds and reservoirs), sedimentation (from road building, development, deforestation, farming), toxic substances (industrial effluent, agricultural and golf course insecticides), and organic enrichment (agricultural and golf course fertilizers, trout farm effluent).3.Nineteen species of Bphemeroptera, 17 species of Plecoptera and 38 species of Trichoptera are identified as examples that are probably rare and vulnerable to extirpation in the southern Appalachian Mountains.4.The task of saving the streams and their biotas from further degradation will require thoughtful public discourse and thorough baseline and long‐term research effort

ISSN:1052-7613    

DOI:10.1002/aqc.3270030404

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.This paper presents a summary of recent patterns of surface discharge in the Arkansas River in Kansas, and discusses the implications of dewatering on aquatic insect communities.2.Significant reductions in surface flows of the Arkansas River have been observed since approximately 1974 in central and western Kansas. Dewatering of the river has been most severe between Syracuse and Great Bend, a distance in excess of 335 river kilometres, and has resulted in complete losses of surface flow for periods in excess of one year at several points along the river.3.Minimum desirable stream flow (MDSF) standards developed and legislated by the state in the early 1980s have had little effect on reversing the trends associated with river dewatering. It must be concluded that dewatering has had substantial effects on aquatic insect communities through habitat modification in areas where surface flows are dramatically curtailed. These communities are extirpated, or nearly so, in areas where dewatering is most pronounced.4.Reduction in groundwater withdrawals from the riverine aquifer and palaeochannels, some of which are considerable distances from the present‐day river channel, must be considered in order to achieve MDSF during periods of dewatering.5.Although it may be possible to achieve MDSF, it is argued that MDSF will not be sufficient to allow for development of habitats that are critical for restoration of ‘natural’ communities. A distinction is made between the ideal and the achievable as goals for a management strategy to conserve habitats for aquatic insects, and it is concluded that the ideal of managing surface flows to restore natural communities cannot be achieved in the light of recent reductions of surface flow and conflicting uses of groundwater for irrigation and minicipal consumption. As an alternative, conceited efforts must be made to ensure that MDSF is continuously ach

ISSN:1052-7613    

DOI:10.1002/aqc.3270030405

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.This paper discusses the karst aquatic ecosystems of the Edwards Plateau, Texas, including a synopsis of those systems that are threatened or endangered by anthropogenic disturbances. Thousands of springs issue from aquifers on the Edwards Plateau, including the largest springs in the state.2.The endemic and unique aquatic biota of the Edwards Plateau are presented, including taxa faced with extinction. Ninety‐one species and/or sub‐species are identified as being endemic to aquatic ecosystems of the Edwards Plateau.3.Threats to aquatic ecosystems are overpumping of aquifers associated with an expanding human population in the region, agricultural practices, urbanization and development, pollution, recreational activities, introductions of exotic species, and changes in regional and global climatic patterns.4.The means for possible protection and remediation of these threatened aquatic systems include public education on water conservation issues, development of water conservation plans, use and development of alternative sources of water, lawsuits, and land management and stewardship program

ISSN:1052-7613    

DOI:10.1002/aqc.3270030406

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.A major effect of impoundment of rivers is the coarsening of the sediment of the bed (‘armouring’). The effect occurs over many tens of kilometres at least and develops over a period of years to tens of years.2.It is postulated that coarsening of the sediment may prevent burrowing benthos from finding suitable habitats and may thus severely diminish the fauna of impounded rivers.3.The upper Delaware River has a depleted fauna of gomphid dragonflies and unionoid bivalves which probably results from the armouring of the bed resulting from impoundm

ISSN:1052-7613    

DOI:10.1002/aqc.3270030407

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.The damselfly genusMegalagrionas presently interpreted contains 23 species and 5 sub‐species, all confined to the Hawaiian Islands. Based on current surveys, 23 of these 28 taxa are still extant, although two lowland species,M. xanthomelasandM. pactficum, appear to be extirpated from certain islands that formerly constituted portions of their original ranges.2.Of the five taxa not yet rediscovered, three (M. williamsoni, M. amaurodytum fallaxandM. amaurodytum waianaeanum) are of questionable taxonomic validity, and the remaining two (M. jugorum and M. molokaiense) are rare and ecologically specialized species that do not occur near the typical aquatic damselfly habitats most frequently surveyed by collectors.3.The current major threats toMegalagrionspecies are competition and predation from introduced fish, frog and invertebrate species, and physical destruction of habitats, particularly on the island of Oah

ISSN:1052-7613    

DOI:10.1002/aqc.3270030408

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.Springs occur in all American deserts but their distribution is patchy and they are very difficult to locate.2.Desert spring floras and faunas exhibit high diversity but many of the included species are undescribed or poorly known.3.The conservation value of desert spring communities involves both their biodiversity and their research opportunities, both pure and applied. The communities offer real‐life results that can help understand the effects of progressive habitat loss and degradation. Thus their study reflects strongly on problems concerning the development and management of natural parks and reserves.4.Factors endangering desert spring systems include the misuse of the spring and/or its supporting aquifer, poor conservation practices and the introduction of exotic specie

ISSN:1052-7613    

DOI:10.1002/aqc.3270030409

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1.Parasimulium(Diptera: Simuliidae) is one of the most distinctive, enigmatic and poorly collected groups of black flies in North America. The genus is confined to streams in the mesic coniferous forests of the Pacific Northwest, from southern British Columbia to northern California.2.The immature stages of these unusual flies are specialized for life in the hyporheic zone, a region of flowing water beneath and lateral to the stream bed.Parasimuliumshares this habitat with a diverse assemblage of subterranean aquatic invertebrates.3.MostParasimuliumresearch has been conducted in the Cascade Range of Oregon, particularly streams in the Columbia River Gorge. Collection records suggest a correlation between the distribution of some species ofParasimuliumand that of ancient forests in the Pacific Northwest. However, definitive evidence thatParasimuliumis an ecologically sensitive ‘indicator’ species awaits additional observations on the group's distribution and habitat requirements.4.This paper discusses the potential role of aquatic invertebrates in studies of ancient forests, and concludes that it may be especially great for hyporheic species, which typically inhabit zones of marked environmental stability. Data on these and other ecologically sensitive taxa will provide valuable insights into the management and conservation of surface and groundwater habitats of the Pacific Northw

ISSN:1052-7613    

DOI:10.1002/aqc.3270030410

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270030401

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY