Persistence in the longitudinal distribution of lotic insects in a changing climate: a tale of two rivers.

The longitudinal distribution of many taxa in rivers is influenced by temperature. Here we took advantage of two older datasets on net-spinning caddisflies (Hydropsychidae) from contrasting European rivers to assess changes in species occurrence and relative abundance along the river by resampling the same sites, postulating that an increase in river temperature over the intervening period should have resulted in cool-adapted species retreating into the headwaters and warm adapted species expanding upstream. Distributional changes in the Welsh Usk were slight between 1968/69 and 2010, one rare species appearing at a single headwater site and one warm-adapted species disappearing from the main river.

A revised description of the larva of Homilia leucophaea (Rambur 1842) (Trichoptera: Leptoceridae) and comparisons with the known western European Athripsodes larvae.

Co-occurrence of mature larvae and male pharate pupae in benthos samples from the Loire River enabled descriptions of the larva of Homilia leucophaea. Using characters of the head capsule, the labrum, the meso- and metanotum, and the pro- and metathoracic legs, we compared H. leucophaea with larvae of six western European Athripsodes species, including a larval key to these species.

Developments in aquatic insect biomonitoring: a comparative analysis of recent approaches.

Aquatic insects and other benthic invertebrates are the most widely used organisms in freshwater biomonitoring of human impact. Because of the high monetary investment in freshwater management, decisions are often based on biomonitoring results, and a critical and comparative review of different approaches is required. We used 12 criteria that should be fulfilled by an "ideal" biomonitoring tool, addressing the rationale, implementation, and performance of a method.

Long-term, large-scale biomonitoring of the unknown: assessing the effects of insecticides to control river blindness (onchocerciasis) in West Africa.

The control of river blindness (onchocerciasis), a human disease transmitted by black flies, has been an economic and public health success in West Africa. It involved insecticide applications to as many as 50,000 km of rivers, almost weekly, in 11 countries between 1974 and 2002. The long-term biomonitoring of the effects of insecticide use on the nontarget invertebrate (primarily insect) and fish communities was initially designed on the basis of limited knowledge available for West African rivers and on information from other areas.

Predicting diversity of juvenile neotropical fish communities: patch dynamics versus habitat state in floodplain creeks.

The species richness of communities should largely depend on habitat variability and/or on habitat state. We evaluated the ability of habitat variability and habitat state to predict the diversity of juvenile neotropical fish communities in creeks of a river floodplain. The young-fish fauna consisted of 73 taxa, and samples were well distributed over a wide range of relevant temporal and spatial habitat variability.

Multiple-site and-year analyses of stream insect emergence: a test of ecological theory.

The use of existing data sets to test applicability of existing ecological theory is an uncommon but potentially cost-effective approach for exploitation of previously accumulated knowledge. Studies on the emergence of insects from small streams have been a major research topic in aquatic ecology, particularly in Austria and Germany; the availability of emergence data from these two countries, covering over 1 million identified specimens, from 18 sites, and for 32 collection years is an example of such exploitable information. Concurrent estimates of annual emergence biomass and annual benthic secondary production for 18 aquatic insect populations showed a statistically significant relationship, contradicting the premise that emergence data do not provide any quantitative measure for a given stream area.

Morphological adaptations of benthic invertebrates to stream flow - An old question studied by means of a new technique (Laser Doppler Anemometry).

The generally accepted concept that dorsoventral flatness and/or small size of benthic stream invertebrates staying on the surface of the bottom substratum allows a current-sheltered life in the boundary layer (Ambühl 1959) is checked by means of the new technique of Laser Doppler Anemometry (LDA). With LDA measurement of flow can be done nearly punctually without any mechanical disturbance. Mapping the current velocities around the body of Ecdyonurus cf.

A method to estimate the population size of benthic macroinvertebrates in streams.

A method is described by which samples of stream macroinvertebrates can be linked to the roughness of the substratum, the water depth, the velocity, and to a combination of these factors, i.e., Froude number and thickness of the laminar sublayer, at the exact point of sampling.