钦州湾越冬鸻鹬类对不同生境的选择分析

2008年12月至2009年1月及2011年12月至2012年1月对钦州湾的越冬鸻鹬类进行了调查,对越冬鸻鹬类退潮后在各类型生境的分布情况和原因进行了分析,以期为制定有效保护越冬鸟类及其生境的措施提供科学依据。冬季在钦州湾记录到鹬鸻类27种,结果表明,在不同的天气情况下退潮后各生境内记录到的鹬鸻类种数和数量均不同,钦州湾不同生境鹬鸻类结构特征随天气变化改变。相似性比较显示,晴天生境相似性指数最高的是盐田-养殖塘生境和农田生境,相似性指数为0.96;相似性指数最低的是红树林滩涂生境和光滩生境,相似性指数为0.49。阴冷天生境相似性指数最高的是光滩生境和盐田-养殖塘生境,相似性指数为0.79;最低是红树林滩涂生境和光滩生境,相似性指数为0.52。分析表明人类活动的干扰对越冬鹬鸻类栖息地选择的影响是巨大的。     

On relation to substrate in sessile rotifers

Information on the distribution of 45 sessile rotifers from diverse freshwaters in south and central Sweden was analyzed to reveal possible relationships to their substrates. Almost all of them showed an exclusively periphytic occurrence. The highest number of species was found on Utricularia, but otherwise it was not possible to correlate rotifer presence to any special macrophyte or category of plants (e.g., fine-leaved or floating-leaved species).     

Occurrence of okadaic acid in the feeding grounds of dugongs (Dugong dugon) and green turtles (Chelonia mydas) in Moreton Bay, Australia

Okadaic acid (OA) is a diarrhetic shellfish poison (DSP) produced by a number of marine organisms including the benthic dinoflagellate Prorocentrum lima, which are often found on seagrass. As seagrass forms the basis of the diet of dugong (Dugong dugon) and green turtle (Chelonia mydas), these herbivores may potentially be exposed to OA through ingestion of P. lima found on the seagrass. In this study, the abundance of epiphytic P. lima, on seagrass, and the concentration of OA produced by these epiphytic dinoflagellates was measured in Moreton Bay, Queensland, Australia. P. lima and OA were found on all four species of seagrass collected. OA was detected in epiphytic material collected from seagrass, with a maximum of 460 ng OA/kg_(wwtSG) found on Halophila spinulosa. From this information, the estimated maximum daily intake (DI) of OA by an adult dugong consuming 40 kg_(wwtSG)/day was 18,400 ng/day, and an adult turtle consuming 2 kg_(wwtSG)/day was 920 ng/day. Analysis by HPLC/MS/MS of 54 stranded dugongs and 19 stranded turtles did not yield OA above the detection limit of 10,000 ng/kg_{(animal tissue)}. OA was found on seagrass, however it was not detected in the tissue samples of dugongs and turtles.     

Nest Site Selection and Spawning by Captive Bred Atlantic Salmon, Salmo salar, in a Natural Stream

Synopsis We examined the physical habitat of nest sites chosen by hatchery Atlantic salmon, Salmo salar, in a recovery program for this extirpated species in Lake Ontario, Canada. We compared the sites used by these captive bred fish to a set of random locations in a wide range of available habitats. Compared to random locations in the stream, the nest sites chosen were lower in the relative abundance of sediment size classes that are detrimental to embryo and juvenile survival. In addition, the process of nest construction by these captive bred fish further reduced the proportions of these detrimental sediments. Although captive breeding may have changed some aspects of the nest site selection and construction behaviour, it has not caused a complete loss or major alteration of the trait and thus does not preclude hatchery fish from restoration or reintroduction programs.     

In situ field experiment shows Lyngbya majuscula (cyanobacterium) growth stimulated by added iron, phosphorus and nitrogen

Coastal waters worldwide have experienced an increase in the occurrence of harmful algal blooms. Over the past decade, nuisance blooms of the toxic cyanobacterium Lyngbya majuscula have increased in frequency and severity in south-east Queensland, Australia, with blooms in Moreton Bay hypothesised to be linked to increased inputs of dissolved nutrients and organic carbon from land-based sources. An in situ field experiment was conducted in northern Moreton Bay (Deception Bay), Australia, to determine the growth response of L. majuscula to phosphorus, nitrogen and organically chelated iron additions to the water column. A three-way analysis of variance showed each of these nutrients stimulated L. majuscula biomass under field conditions, with organically chelated iron (FeEDTA) > phosphorus > nitrogen. Concurrent addition of all three nutrients [FeEDTA + P + N] caused the greatest response being 18 times the control after 49 days; this resulted in an additional 928 g_dw m⁻² of L. majuscula biomass over the control (54 g_dw m⁻²). These results show that water borne nutrients, particularly organically chelated iron, phosphorus and nitrogen can promote prolific growth of the bloom-forming cyanobacterium L. majuscula. It is also likely that the addition of iron and/or phosphorus stimulated nitrogen fixation in L. majuscula, based on the large L. majuscula biomass and higher tissue nitrogen content in the iron and phosphorus treatments. Enrichment with poultry litter (sourced from the adjacent catchment) also substantially enhanced L. majuscula biomass. The experiment shows that a precautionary approach to limit or reduce nutrient additions to streams, estuaries and coastal waters is justified; otherwise the magnitude of L. majuscula blooms is likely to increase in Moreton Bay in the future.     

盐地碱蓬盐沼与相邻泥质滩涂湿地迁徙期鸻鹬类的群落组成及行为差异

盐地碱蓬(Suaeda salsa)盐沼湿地是黄渤海地区河口区域的重要湿地类型, 是水鸟迁徙停歇期的重要栖息地。本研究以辽河口国家级自然保护区为研究地点, 通过对盐地碱蓬盐沼湿地和相邻泥质滩涂两个固定样区连续三年的水鸟组成调查和行为观察, 分析盐地碱蓬盐沼湿地在鸻鹬类多样性维持和栖息地利用中的作用。共记录到鸻鹬类水鸟28种6,348只次, 其中盐地碱蓬湿地记录到4科13种, 泥质滩涂记录到4科27种, 泥质滩涂的物种多样性显著高于盐地碱蓬盐沼湿地。此外, 盐地碱蓬盐沼湿地与相邻的泥质滩涂的鸻鹬类鸟类群落组成存在较大差异, 盐地碱蓬盐沼湿地的鸟类群落组成以体型较大的大杓鹬(Numenius madagascariensis)、白腰杓鹬(N. arquata)、灰鸻(Pluvialis squatarola)等为主, 而泥质滩涂以环颈鸻(Charadrius alexandrinus)、黑腹滨鹬(Calidris alpina)等小型鸻鹬类为主, 这说明两种生境在鸟类多样性维持中具有不同的功能。行为分析发现, 泥质滩涂中栖息鸟类的主要行为为取食(58.71%-93.26%), 而盐地碱蓬盐沼湿地鸟类的行为既包括较大比例的取食, 也包括休息, 特别是在春季迁徙期。这进一步说明, 两种生境在水鸟的栖息地利用中具有一定的生态功能差异。尽管盐地碱蓬盐沼湿地记录到的鸟类物种数和数量均低于泥质滩涂, 但是, 两种生境中存在较大比例的共同分布物种, 这说明其生态功能具有较强的生态互补性, 二者作为一种独特的湿地景观组合, 在鸻鹬类迁徙停歇期的栖息地利用和物种多样性维持中发挥着不可替代的作用。     

Three new species of Prosorhynchoides (Digenea: Bucephalidae) from Tylosurus gavialoides (Belonidae) in Moreton Bay,Queensland, Australia

We surveyed 30 individuals of Tylosurus gavialoides (Castelnau) (Belonidae) collected from Moreton Bay, Queensland, Australia, and describe three new species of Prosorhynchoides Dollfus, 1929 from them. The new species are morphologically distinct from existing Prosorhynchoides spp. and 28S and ITS-2 ribosomal DNA data further supports our morphological findings. We also conduct the first mitochondrial DNA analysis of species of Prosorhynchoides. The new species from T. gavialoides form a strongly supported clade on the basis of the two ribosomal markers, further supporting the emerging hypothesis that bucephaline clades are strongly associated with host groups. We have not observed any of the new species reported here in over 3500 surveyed individuals of other piscivorous fish in Australia, suggesting that these species are host-specific at least to belonids, if not to only T. gavialoides. Our findings support previous reports that suggest that belonids are exceptional hosts for bucephalids. We predict that further sampling of the numerous other belonid species present in Australian waters, for which nothing is known of the bucephalid fauna, will uncover further bucephalid richness.     

动物的生境选择

动物的生境选择颜忠诚陈永林（中国科学院动物研究所,北京１０００８０）ＨａｂｉｔａｔＳｅｌｅｃｔｉｏｎｉｎＡｎｉｍａｌｓ．ＹａｎＺｈｏｎｇｃｈｅｎｇ,ＣｈｅｎＹｏｎｇｌｉｎ（ＩｎｓｔｉｔｕｔｅｏｆＺｏｏｌｏｇｙ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｂｅｉｊｉ...