Assessing Biological Control Damage of Giant Salvinia with Field Reflectance Measurements and Aerial Photography

A study was conducted on a small pond in southeast Texas to evaluate the potential for using remote sensing technology to assess feeding damage on giant salvinia ( Salvinia molesta Mitchell) by the salvinia weevil ( Cyrtobagous salviniae Calder and Sands). Field spectral measurements showed that moderately damaged and severely damaged plants had lower visible and near-infrared reflectance values than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be differentiated in an aerial color-infrared photograph of the study site. Computer analysis of the photograph showed that the three damage level classes could be quantified. (PDF has 5 pages.)

Light Reflectance Characteristics and Remote Sensing of Waterlettuce

Waterlettuce ( Pistia stratiotes L.) is a free-floating exotic aquatic weed that often invades and clogs waterways in the southeastern United States. A study was conducted to evaluate the potential of using remote sensing technology to distinguish infestations of waterlettuce in Texas waterways. Field reflectance measurements showed that waterlettuce had higher visible green reflectance than associated plant species. Waterlettuce could be detected in both aerial color- infrared (CIR) photography and videography where it had light pink to pinkish-white image tonal responses. Computer analysis of CIR photographic and videographic images had overall accuracy assessments of 86% and 84%, respectively. (PDF contains 6 pages.)

Limnology in Sicily: A history of fresh waters surrounded by the sea

The aim of this short article is to trace the history of limnology in Sicily, from the end of the last century up to the present, and pay a little homage to a scientist to whom limnology is deeply indebted: G.E. Hutchinson. Due to its insular and climatic conditions, Sicily is characterised by a drainage network formed by numerous short, torrent-like rivers, and by a few small, natural lakes. The geological characteristics of the island strongly condition the quality of these small waterbodies which generally have surface areas of less than 0.2 km super(2). The earliest observations on Sicilian lentic waters go back more than a century; in particular, at the end of the 19th century, some of the issues regarding the natural lakes had already been brought into focus. Subsequent studies on natural waterbodies concentrated on the geomorphology of landslide lakes or lakes created by the dissolution of the gypsum tableland. However, many of the waterbodies no longer exist because of land reclamation which took place up to the first half of the 1950s. During the last 35 years, there has been a notable increase in limnological publications. In addition, these studies show a more careful and integrated approach to the limnological aspects of waterbodies, compared with the early studies.

Fernando de Buen. Ictiólogo Iberoamericano.

Este documento está dedicado al recuerdo de Fernando de Buen, a quién podríamos considerar como uno de los primeros “ictiólogos iberoamericanos”. En este caso nos encontramos con un profesional que, por la locura de una guerra fratricida, tuvo que dejar su patria y trasladarse al continente americano, residiendo inicialmente en México dónde adopta su ciudadanía. Posteriormente viaja a Sudamérica para trabajar en Uruguay y luego en Chile. En esa extensa travesía generó parte de su legado, dejando aportes substanciales para el crecimiento y consolidación de la ictiología neotropical. Por ello, a más de cincuenta años de su desaparición, junto a la invalorable colaboración de los colegas de Chile, España, México y Uruguay, concretamos este modesto archivo con la idea de que su figura y su obra no se pierdan en la “bruma de los tiempos” y que las jóvenes generaciones conozcan a quiénes abrieron los surcos de nuestra disciplina aún, como en este caso, llevando consigo el dolor y la angustia del destierro.