Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

The Ecology of Gammarus duebeni Lilljeborg and its Occurrence in Fresh Water in Western Britain

H. B. N. Hynes
Journal of Animal Ecology
Vol. 23, No. 1 (May, 1954), pp. 38-84
DOI: 10.2307/1660
Stable URL: http://www.jstor.org/stable/1660
Page Count: 47
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Ecology of Gammarus duebeni Lilljeborg and its Occurrence in Fresh Water in Western Britain
Preview not available

Abstract

1. Literature on the ecology and distribution of G. duebeni Lillj. is briefly reviewed. 2. In Britain G. duebeni occurs in brackish water all round the coasts, but in fresh water only on the western and northern islands; it is not normally found in fresh water on the same land mass as G. pulex, which is almost confined to the British mainland. 3. The only two areas where both species occur in fresh water were studied in detail. On the Lizard peninsula the areas occupied are not contiguous. In the Isle of Man their areas overlap and in two streams they were found together. It is suggested that G. pulex is a recent introduction into the island. 4. Investigations on interbreeding, osmoregulation, kidney structure, size, and number and size of eggs have produced no support for the suggestion that there are distinct physiological races of G. duebeni in fresh and brackish water. 5. The diets of G. pulex and G. duebeni are shown to be similar. 6. The life cycles of G. duebeni in fresh and brackish water were found to differ; it is suggested that this is because of slight temperature differences. 7. Investigations of geology, dissolved salts, temperature, and associated flora and fauna have failed to explain why G. duebeni does not occur in all streams in areas where it is found. These investigations throw some doubt on the accepted ideas about the importance of dissolved salts to G. pulex. 8. In the laboratory it was found impossible to induce G. duebeni to breed and mature in still fresh water, although it did so in waters of relatively high ion content. It seems that the species needs running fresh water in order to complete its life cycle. 9. It appears that G. duebeni is potentially able to colonize certain types of fresh water, but that it is unable to do so in face of competition from G. pulex. It is suggested that the latter is extending its range in Britain and that when it arrives on a new land mass it eliminates G. duebeni from fresh water. Introduction experiments to investigate this are in progress.

Page Thumbnails

  • Thumbnail: Page 
38
    38
  • Thumbnail: Page 
39
    39
  • Thumbnail: Page 
40
    40
  • Thumbnail: Page 
41
    41
  • Thumbnail: Page 
42
    42
  • Thumbnail: Page 
43
    43
  • Thumbnail: Page 
44
    44
  • Thumbnail: Page 
45
    45
  • Thumbnail: Page 
46
    46
  • Thumbnail: Page 
47
    47
  • Thumbnail: Page 
48
    48
  • Thumbnail: Page 
49
    49
  • Thumbnail: Page 
50
    50
  • Thumbnail: Page 
51
    51
  • Thumbnail: Page 
52
    52
  • Thumbnail: Page 
53
    53
  • Thumbnail: Page 
54
    54
  • Thumbnail: Page 
55
    55
  • Thumbnail: Page 
56
    56
  • Thumbnail: Page 
57
    57
  • Thumbnail: Page 
58
    58
  • Thumbnail: Page 
59
    59
  • Thumbnail: Page 
60
    60
  • Thumbnail: Page 
61
    61
  • Thumbnail: Page 
62
    62
  • Thumbnail: Page 
63
    63
  • Thumbnail: Page 
64
    64
  • Thumbnail: Page 
65
    65
  • Thumbnail: Page 
66
    66
  • Thumbnail: Page 
67
    67
  • Thumbnail: Page 
68
    68
  • Thumbnail: Page 
69
    69
  • Thumbnail: Page 
70
    70
  • Thumbnail: Page 
71
    71
  • Thumbnail: Page 
72
    72
  • Thumbnail: Page 
73
    73
  • Thumbnail: Page 
74
    74
  • Thumbnail: Page 
75
    75
  • Thumbnail: Page 
76
    76
  • Thumbnail: Page 
77
    77
  • Thumbnail: Page 
78
    78
  • Thumbnail: Page 
79
    79
  • Thumbnail: Page 
80
    80
  • Thumbnail: Page 
81
    81
  • Thumbnail: Page 
82
    82
  • Thumbnail: Page 
83
    83
  • Thumbnail: Page 
84
    84