Habitat selection and sampling design for ecological assessment of heterogeneous ponds using macroinvertebrates

Abstract

ABSTRACT1. Habitat heterogeneity has many implications in ecological assessment studies. On one hand it provides varying niches for organisms, increasing diversity. On the other hand, the inherent spatial variability of structurally complex systems may overlap with ecological condition making it difficult to disentangle the effects of perturbation. This study investigated the combined and single effects of habitat and pond condition on the macroinvertebrate assemblages of 35 ponds located in north-west Spain and spanning a range of water quality and habitat characteristics.2. Macroinvertebrate communities and several environmental variables were sampled in the summer of 2004 or 2003. Samples were collected from four dominant habitats (vegetated shores, shores without vegetation, submerged vegetation, bare sediments) following a time-limited sampling. Non-metric multidimensional scaling and two-way crossed ANOSIM were used to investigate the taxonomic and functional differences in macroinvertebrate assemblage structure among habitats (four types) and pond conditions (optimal, good, moderate, poor, very poor). To investigate the individual and combined effects of pond condition and habitat on several diversity measures GLM models were used. In addition, the accuracy of two sampling designs -stratified and multihabitat -was compared using the CVs of seven macroinvertebrate attributes.3. Results showed that macroinvertebrate communities differed significantly, albeit weakly, among habitat types and pond condition categories. In particular, the abundance of several Chironomidae genera, rarefied richness and Shannon index decreased both in perturbed systems and bare sediments, whereas no marked differences occurred between shores and submerged vegetation.4. We suggest that a multihabitat approach together with the use of community attributes not (or slightly) affected by habitat type will provide more comparable results across ponds than a stratified approach or observation of the whole community, especially in ponds where degradation leads to habitat loss.

Response of Benthic Invertebrate Communities in River-Changed Ponds to River Habitat Modification in Water-Deficient Area

“…Most of these environmental drivers are associated with water flowing. In contrast, invertebrate assemblages seem to be primarily affected by various aspects of vegetation in lentic environments (Trigal-Dominguez et al 2009). However, river-changed ponds in water-deficient areas are different from running rivers and totally lentic lakes.…”

The impact of natural succession process on waterbird community in a abandoned fishpond at Chongming Dongtan, China

“…Key Words: abandoned fishpond; natural succession; waterbird community; Chongming Dongtan 由于人类活动的影响,湿地受损或功能退化已成为全球性的普遍现象,并对湿地的生物多样性带来巨大 威胁。 水鸟是在生态上依赖湿地生存的鸟类, 对环境的变化又相对敏感, 因此可以视为环境变化的指示 剂 [1] 。 近年来,随着围垦的加重和天然湿地的恶化,人工湿地成为水鸟利用的重要湿地类型 [2] 。 然而,在建 造各种人工湿地的同时,也普遍存在着将湿地抛荒的现象 [3鄄 5] 。 许多研究表明,鱼塘抛荒可导致土壤和水质 的变化,水生底栖动物的减少 [3,6] 14] 。 湿地类型的改变会对水鸟群落的分布和分配产生很大影响 [15] 。 不同 的水深 [4,16] 水分布 [17] 和水位变化 [18] 能影响水鸟的分布情况。 水面和光滩面积比例的逐渐减少,以及植被盖 度的逐渐增加,都标志着该区域的自然演替和逐渐旱化过程。 干旱能导致底栖动物的密度下降 [17] ,能直接导 致水鸟食物资源的短缺。 而植被密度的增加会使许多水鸟无法站立栖息 [19] ,造成水鸟栖息的有效湿地面积 的减少 [21] 。 一般认为人为干扰会对鸟类密度和多样性造成负面影响 [21鄄 22] ,但有些水鸟已经适应了水产养殖 活动带来的干扰 [23] ,并对规律性的干扰或人为活动具有一定的依赖性,因此不可一概而论。 [24] ,而抛荒后的环境不适合鹈形目水 鸟的生存,因此鹈形目只在抛荒前有记录。 目、雁形目、鹤形目水鸟具有相似的生境需求,喜好水位较深、 具有大明水面且存在斑块状芦苇的养殖塘 [10] ,因此抛荒前以雁鸭类数量占优势。 鹳形目水鸟多为涉禽,主要 分布在浅水区域和泥滩地 [25] [10] ,通过人工调控维持一定的水位。 植被在决定环境的自然结构上有重要的作用 [29] , 针对雁鸭类对人为干扰较为敏感的特点 [30] ,需要保留一定的植被为水鸟提供隐蔽场所 [31] 。 (2) 春秋季:春季 和秋季是候鸟的迁徙期,就崇明东滩来说,以鸻鹬类的种类和数量为最多。 为了迎合鸻鹬类水鸟的生境需求, 春季和秋季需要营造具有低植被盖度、充足光滩面积和水位较浅的生境 [32鄄 33] 。 考虑到春季部分越冬水鸟的 残留和秋季冬候鸟逐渐增加的趋势 [34] ,建议保留一定的深水区域,以增加环境异质性,提高物种多样性…”