Stream crossings and the conservation of diadromous invertebrates in South Pacific island streams

• 1. Most non‐insect invertebrates that occur in streams on tropical Pacific islands are diadromous; they live as juveniles and adults in streams but have larvae that migrate to the ocean to complete their development before returning to fresh water.
• 2. The type of crossing used in the construction of roads to traverse small streams can impede upstream migration and, consequently, colonization of diadromous fauna above the stream crossing.
• 3. A stream in the Opunohu Valley, Moorea, French Polynesia, had the same diadromous fauna of atyid shrimps, palaemonid prawns, and neritid snails occurring above and below an 8 m wide, 10 m long, bottomless culvert (i.e. an open‐bottom bridge) built to flow over natural substrates. However, no diadromous species were found upstream of two 1 m diameter, 8 m long concrete pipes used for a culverted stream crossing. The increased shear stress in the pipe and subsequent downstream erosion of the stream bed probably inhibited upstream migration.
• 4. Modifications to culverted stream crossings, which are widely used on tropical islands, can reduce migration barriers and prevent upstream loss of diadromous stream fauna.

Copyright © 2004 John Wiley & Sons, Ltd.     

Importance of cryptic species for identifying ‘representative’ units of biodiversity for freshwater conservation

Nested systems of biodiversity classification are commonly used for designating protected area networks in terrestrial and marine realms. Whilst terrestrial-style protected areas are largely inappropriate for freshwater systems, the concepts of ‘representative’ biodiversity and ‘complementarity’ can be borrowed for freshwater conservation. Cryptic species are commonly found in freshwater macroinvertebrates and fish, and most have restricted distributions relative to the described conglomerate ‘species’. This indicates that ‘representative’ and therefore ‘complementary’ units of freshwater biodiversity may be smaller than previously appreciated. Using recently detected cryptic species in atyid shrimps from eastern Australia (Atyidae: Paratya australiensis, Caridina mccullochi and C. indistinca), we tested predictions about regional patterns of cryptic assemblage structure, endemism and Phylogenetic Diversity (PD) at the river scale, and discussed their implications for freshwater conservation. Patterns of distribution in these cryptic shrimp species largely corresponded with published distributional patterns of cryptic species in several freshwater fish in eastern Australia, and indicated the presence of four putative ecoregions within a previously recognised freshwater fish province (Eastern Province). However, some rivers had pronounced cryptic endemism, suggesting that rivers may not be ‘representative’ of one another’s biodiversity even within ecoregions. PD and endemism were largely correlated with one another, as endemics typically co-occurred with widespread species at the river scale. This study indicates that cryptic species can contribute to defining patterns of biodiversity at nested spatial scales that may be important for freshwater conservation.     

福建新米虾属一新种记述 (十足目:匙指虾科)

霞浦新米虾（新种）Neocaridina xiapuensis,sp.nov。与安徽新米虾Neocaridina palmata anhuiensis相似，但前者经三对步足无明显的两性异形现象，且雄性第二腹肢雄附肢的形态结构和较小的卵径与后者均有显著不同。     

湖南米虾的研究（十足目：匙指虾科）

本文报道湖南省的米虾，计7种，其中有3个新种，即舌肢米虾、锉肢米虾和湖南米虾。     

The conservation status of decapod crustaceans in the Western Ghats of India: an exceptional region of freshwater biodiversity

相似文献   

湖南匙指虾一新种报道

湖南省匙指虾一新种－－梁氏米虾Caridina liangi sp.nov.与秉氏米虾（Caridina pingi Yu,1936）在形态上略相似，但新种的头胸甲上无颊刺；雄性第一腹肢内肢呈长方形，其内缘平直，无凹陷；雄性第二腹肢雄附肢呈短棒状，内缘与末端具一长一短两行刺等特征可明显区别于秉氏米虾。     

福建新米虾属一新种记述 (十足目:匙指虾科)

霞浦新米虾（新种）Neocaridina xiapuensis,sp.nov。与安徽新米虾Neocaridina palmata anhuiensis相似，但前者经三对步足无明显的两性异形现象，且雄性第二腹肢雄附肢的形态结构和较小的卵径与后者均有显著不同。     

湖南米虾的研究（十足目：匙指虾科）

本文报道湖南省的米虾，计7种，其中有3个新种，即舌肢米虾、锉肢米虾和湖南米虾。