THE GROUND CENSUSES ON RED-CROWNED CRANE IN KHANKA LAKES DISTRICT OF CHINA

Coordination of the aenal servey,the author carried ground census on the popula-tion size of Red-erowned crane(Grus japonensis)in Khanka Lakes District from 1984 to 1986.Ac-cording to the census in spring of 1984,the total number of Red-crowncd crane is 72 individualsand 20 nests.So that this pound census has recorded 59 indivlduals more than the aerial survey of13 individuals,and the percentage of nesting individuals in his flock is 55.6％,which is obviouslyhigher than 36.9％ of the average ration in China.After this,in fall of 1984 and in spring of 1985 and1986,we repeated the same censuses three times in the same districts,the results indicated that theflock of the crane in Khanka Lakes District is stable basiuclly,but some individuals interchangewith opposite flock of USSR because of gegraphical adjoin So,We blieve this flock in China andthat lock in USSR belong to the same population and suggest two countries should act in concertto studing on this population in future. Meanwhile,the aerial servey     

梅州市柑橘黄龙病的发生与防治

对梅州市柑橘黄龙病的发生情况进行普查,对采集的152个黄龙病样进行检测,结果表明:梅州地区已有柑橘黄龙病的发生,在此基础上提出防治方法,以为当地柑橘黄龙病的防治提供参考。     

Coastal breeding aggregations of threatened stingrays and guitarfish in the Levant

1. Stingrays and guitarfish are globally threatened by overexploitation, particularly so in the Mediterranean Sea. Nevertheless, very little information is known about their ecology, behaviour, and taxonomy in the Mediterranean, and especially in the Levant, where water temperature, salinity, and the impact of invasive species are relatively high.
2. Although it has been suggested that some species may aggregate in the Levant, this has not been formally documented and the scale of this phenomenon, the taxonomic composition, and the temporal dynamics are unknown.
3. Visual surveys were conducted, which allowed the documentation of stingrays and guitarfish behaviour, and which was not available from data based on fishery catches. The census took place within a marine protected area over a period of 3 years.
4. Altogether, we documented 675 batoid observations. One of the observed species is Endangered (Glaucostegus cemiculus) and one is Vulnerable (Dasyatis pastinaca), whereas the others are classed as Least Concern (Torpedo torpedo and Torpedo marmorata), Data Deficient (Taeniurops grabatus), non‐assessed within the Mediterranean (Dasyatis chrysonota), and Not Evaluated (Himantura uarnak). Results show clear seasonal patterns, with dense aggregations recorded during spring and early summer, when densities reached 85 observations per kilometre. In addition, there were clear indications of breeding behaviour in D. pastinaca and D. chrysonota, including the first recorded documentation of D. pastinaca courtship in the Mediterranean.
5. Large seasonal stingrays and guitarfish aggregations in shallow waters have not, to our knowledge, been documented in the Mediterranean Sea previously. This highlights the importance of conserving shallow habitats as potential breeding grounds. As these sites are easily reached while both snorkelling and diving, the aggregation of these charismatic species can serve as potential ecotourism sites. Finally, this study shows the benefits of using simple visual census, as opposed to catch‐based methods, to record both the diversity and the behaviour of batoids.

     

Re‐evaluating the population size of South American fur seals and conservation implications

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