Managing Critical Transition Zones

ABSTRACT Ecosystems that function as critical transition zones (CTZs) among terrestrial, freshwater, and marine habitats are closely connected to the ecosystems adjacent to them and are characterized by a rapid flux of materials and organisms. CTZs play various roles, including mediating water flows, accumulating sediments and organic matter, processing nutrients, and providing opportunities for recreation. They are particularly difficult to manage because they tend to be small, albeit important, components of large watersheds, and managers may not have control over the entire landscape. Moreover, they are often the focus of intensive human activity. Consequently, CTZs are critically important zones, and their preservation and protection are likely to require unique collaboration among scientists, managers, and stakeholders. Scientists can learn a great deal from the study of these ecosystems, taking advantage of small size and the importance of fluxes, but a good understanding of adaptive management strategies is needed to establish a dialogue with managers and stakeholders on technical and management issues. An understanding of risk analysis is also important to help set meaningful goals and establish logical strategies that include all of the interested parties. Successful restoration of a CTZ is the best test of the quality of knowledge about its structure and function. Much has already been learned about coastal CTZs through restoration projects, and the large number of such projects involving riparian CTZs in particular suggests that there is considerable opportunity for fruitful collaborations between scientists and managers

Dry mass estimation of tropical aquatic insects using different short-term preservation methods

Relationships of body mass and head capsule width were calculated for Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp. and Nectopsyche sp. (Trichoptera), and Anacroneuria sp. (Plecoptera) using different preservatives (Freezing, Formaldehyde 4% and Kahle). The organisms were collected monthly during a year on the Orituco river, Venezuela with a Surber net (0. 1296 m2 and 0.286 mm mesh size). The data presented here are representative of the organism conditions year around. No attempt was made to quantify intersample variation. Regression analysis indicated that all relationships were highly correlated for any of the fixatives used. Changes in dry mass per unit change of head capsule width, vary among species and preservatives with no clear relationship among them. Changes in dry mass calculated as the difference between dry mass of preserved samples to those of unpreserved ones, indicate that all fixatives underestimate dry mass by as much as 85.4%, except for Nectopsyche sp. whose dry mass was always overestimated. These results provide further evidence on the effect of preservatives on dry mass losses. Even when working with tropical species, any study in which biomass is going to be determined should consider the effect of preservatives on dry mass.Se calcularon las ecuaciones para las relaciones entre la masa del cuerpo y el ancho de la cápsula cefálica para Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp., Nectopsyche sp. (Trichoptera) y Anacroneuria sp. (Plecoptera) usando diferentes preservativos (Congelamiento, Formol 4% and Kahle). El análisis de regresión indicó que todas las relaciones obtenidas son altamente significativas para cada uno de los preservativos utilizados. Los cambios en la masa del cuerpo por unidad de cambio en el ancho de la cápsula cefálica, son diferentes para cada especie y preservativo, sin haberse obtenido una clara relación entre ellos. La compararación entre los valores de masa obtenidos con los diferentes preservativos y los obtenidos con muestras no preservadas, indica que todos los preservativos subestiman la masa seca hasta en un 85,4%, excepto en el caso de Nectopsyche sp. cuya masa corporal fue siempre sobre-estimada. Los resultados presentados en este trabajo nuevamente indican, aún trabajando con insectos acuáticos tropicales, que cualquier estudio en el cual la biomasa va a ser determinada, debe de tener en cuenta el efecto que los preservativos producen en la disminución de la masa corpora

Dry mass estimates of some tropical aquatic insects

Relationships of body mass and head capsule width were developed for Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp., Phylloicus sp. Nectopsyche sp. (Trichoptera), and Anacroneuria sp. (Plecoptera). The organisms were collected with a Surber net (0.1296 m² and 0.286 mm mesh size) on the Orituco river, Venezuela. The number of specimens used in the analysis for the species studied, was different (from 84 to 103 specimens). Regression analysis indicated that all relationships were best expressed by a power function rather than by linear or exponential equation. Analyses of the relationships reveal interspecific differences among insects of the same order. Species-specific relationships are recommended to be used whenever possible since, depending on the species, the underestimation of mass could be as much as 56%.<br>Se calcularon las relaciones entre la masa del cuerpo y el ancho de la capsula cefálica para Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp., Phylloicus sp., Nectopsyche sp. (Trichoptera), y Anacroneuria sp. (Plecoptera). Los análisis de regresión indicaron que todas las relaciones se expresan adecuadamente mediante la función potencial en vez de la función exponencial o linear. El análisis de las relaciones obtenidas revela diferencias entre los insectos pertenecientes a un mismo Orden. Se recomienda el uso de relaciones específicas para cada especie siempre y cuando sea posible, debido a que, dependiendo de la especie, la subestimación de la masa puede llegar a ser hasta de un 56%

Variaciones diarias en algunos parámetros químicos del Río Orituco, Venezuela.

[email protected] analítica--semestra

Dry mass estimates of some tropical aquatic insects

Relationships of body mass and head capsule width were developed for Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp., Phylloicus sp. Nectopsyche sp. (Trichoptera), and Anacroneuria sp. (Plecoptera). The organisms were collected with a Surber net (0.1296 m2 and 0.286 mm mesh size) on the Orituco river, Venezuela. The number of specimens used in the analysis for the species studied, was different (from 84 to 103 specimens). Regression analysis indicated that all relationships were best expressed by a power function rather than by linear or exponential equation. Analyses of the relationships reveal interspecific differences among insects of the same order. Species-specific relationships are recommended to be used whenever possible since, depending on the species, the underestimation of mass could be as much as 56%.Relationships of body mass and head capsule width were developed for Thraulodes sp., Haplohyphes sp. (Ephemeroptera), Leptonema sp., Phylloicus sp. Nectopsyche sp. (Trichoptera), and Anacroneuria sp. (Plecoptera). The organisms were collected with a Surber net (0.1296 m2 and 0.286 mm mesh size) on the Orituco river, Venezuela. The number of specimens used in the analysis for the species studied, was different (from 84 to 103 specimens). Regression analysis indicated that all relationships were best expressed by a power function rather than by linear or exponential equation. Analyses of the relationships reveal interspecific differences among insects of the same order. Species-specific relationships are recommended to be used whenever possible since, depending on the species, the underestimation of mass could be as much as 56%

Hifomicetos acuaticos de dos ríos de aguas negras de venezuela.

[email protected]@ciens.ucv.veReferencia analítica--semestra

Physico-chemical characteristics of the water of the Guanapito reservoir, Venezuela.

[email protected] analítica--semestra

PRELIMINARYSTUDYOFAQUATIC HYPHOMYCETES FROM VENEZUELAN STREAMS

RESUMENSe reportan 50 especies de hifomicetes acu&aacute;ticos encontrados en siete cursos de agua,de los cuales seis est&aacute;n ubicados en Parques Nacionales. La comunidad de hifomicetes present&oacute;baja similitud ya que s&oacute;lo cuatro especies fueron comunes en las diferentes localidades:Campylospora chaetocladia Ranzoni, Clavatospora tentacula Sv.Nilsson, Triscelophorusacuminatus Nawawi y Triscelophorus monosporus Ingold. La mayor&iacute;a de los r&iacute;os tienen especiesparticulares cuyo n&uacute;mero oscila entre uno y tres. En el R&iacute;o Los Castillos las especiesfueron: Anguillospora longissima (Sacc. &amp; P.Syd) Ingold, Angulospora aquatica Sv.Nilssony Phalangispora nawawi Kuthub.; en la Quebrada Guatopo las especies encontradas fueronClavariopsis azlanii Nawawi, Condylospora flexuosa Nawawi &amp; Kuthub. e Hydrometrosporasymmetrica J.G&ouml;ncz&ouml;l &amp; R&eacute;vay; para el R&iacute;o Cabriales las especies fueron Camposporiumantennatum Harkn., Phalangispora constrica Nawawi &amp; J.Webster y Scorpiosporium chaetocladium(Ingold) Dyko. Quebrada Martinera y R&iacute;o Tocome tienen una especie exclusiva,Isthmotricladia gombakiensis Nawawi y Flabellospora verticillata Alas., respectivamente.El R&iacute;o C&uacute;pira y la Quebrada Ingenio no presentaron especies &uacute;nicas. Se reportan 30 especiespor primera vez para el pa&iacute;s.&nbsp;ABSTRACT&nbsp;Fifty species of aquatic hyphomycetes from seven streams, six of which are located inVenezuelan National Parks are reported. Community similarity of hyphomycetes was lowsince only four species were common to all sites: Campylospora chaetocladia Ranzoni,Clavatospora tentacula Sv.Nilsson, Triscelophorus acuminatus Nawawi and Triscelophorusmonosporus Ingold. The streams had unique species whose number varies between one&nbsp;and three. In R&iacute;o Los Castillos the species were: Anguillospora longissima (Sacc. &amp; P.Syd.)Ingold, Angulospora aquatica Sv.Nilsson and Phalangispora nawawiKuthub.; for QuebradaGuatopo the species were Clavariopsis azlanii Nawawi, Condylospora flexuosa Nawawi&amp; Kuthub. and Hydrometrospora symmetrica J.G&ouml;ncz&ouml;l &amp; R&eacute;vay; for R&iacute;o Cabriales thespecies were Camposporium antennatum Harkn., Phalangispora constrica Nawawi &amp;J.Webster, Scorpiosporium chaetocladium (Ingold) Dyko. Quebrada Martinera and R&iacute;o Tocomehad one species unique Isthmotricladia gombakiensis Nawawi and Flabellosporaverticillata Alas., respectively. R&iacute;o C&uacute;pira and Quebrada Ingenio do not have species exclusivelyto any of them. Thirty species are reported for the first time for the country

Notalina roraima Holzenthal 1986 (Trichoptera: Leptoceridae), male genitalia variability and larval description

Zamora-Muñoz, Carmen, Derka, Tomáš, Cressa, Claudia (2013): Notalina roraima Holzenthal 1986 (Trichoptera: Leptoceridae), male genitalia variability and larval description. Zootaxa 3702 (5): 450-458, DOI: 10.11646/zootaxa.3702.5.