[Maintaining mechanisms of riparian invertebrate biodiversity: A review]. / æ²³å²¸æ— è„Šæ¤ŽåŠ¨ç‰©å¤šæ ·æ€§ç»´æŒæœºåˆ¶ç ”ç©¶è¿›å±•.

Riparian zones, the critical ecological interfaces between terrestrial and aquatic ecosystems, are species rich habitats. However, riparian zones are seriously threatened by human activities in the world. Riparian invertebrates represent a large proportion of riparian biodiversity, perform various ecological functions, and provide an essential link between aquatic and terrestrial ecosystems. Although many studies have investigated the riparian invertebrate communities, there is lacking a comprehensive summary of maintaining mechanisms underlying riparian invertebrate diversity. This review discussed seven characteristics of riparian zones that might support high riparian invertebrate diversity: flood and drought, nutrient, microhabitat diversity, riparian vegetation, microclimate gradients, food resources and river spatial gradients. Further, we summarized the maintaining mechanisms of riparian invertebrate diversity. Disturbances of periodic flood and drought trigger the reproduction and migration of invertebrates, increase the turnover of invertebrate communities, and create suitable conditions for riparian invertebrates. Adequate nutrients support a high invertebrate diversity by increasing primary productivity of riparian habitats. Elevated microhabitat diversity provides a variety of niche space for specialist riparian invertebrates. Strong microclimate gradients provide complex and diverse habitats and thus facilitate the coexistence of aquatic and terrestrial invertebrates in riparian zones. Cross-ecosystem resource subsidies increase food availability and contribute unique food sources to riparian invertebrates. The differentiation of these factors along river longitudinal and lateral gradients provides conditions for the diversification of riparian invertebrates at a larger scale. Understanding the maintaining mechanisms of riparian invertebrate diversity is important for conservation of riparian biodiversity and integrated management of river ecosystems.

[Role of GDNF in the behavior and cognitive impairment of mice induced by chronic stress and aging].

OBJECTIVE: To investigate the effects of chronic stress on the spatial learning-memory and the role of glial cell line-derived neurotrophic factor (GDNF) of prefrontal cortex (PFC) and hippocampus (HP) in different age mice. METHODS: The chronic stress model mice in 21 days with multiple chronic unpredictable stressors were applied. The spontaneous behavior and spatial learning-memory ability of mice were tested, using Open field and Morris water maze task, and the expression of GDNF in HP and PFC were detected by immunohistochemical method. RESULTS: Compared with young mice, the spontaneous behaviors were significantly decreased and the spatial learning-memory function were significantly decreased (P < 0.05, P < 0.01) in aged mice. The GDNF expression in the CA3, DG of HP and PFC were significantly reduced in aged mice (P < 0.05, P < 0.01). After chronic stress, the spontaneous behaviors were remarkably decreased and the ability of spatial learning-memory of the stress group mice were significantly decreased (P < 0.05, P < 0.01) compared with those of the control group mice. The expression of GDNF in HP and PFC were remarkably reduced (P < 0.05, P < 0.01) in stress group mice. The aged stress mice had more serious changes after chronic stress. CONCLUSION: The brain aging and chronic stress in mice causes behavioral changes and the damage of spatial learning-memory function, and which may be nearly related to the expression of GDNF in HP and PFC.