ECOLOGICAL STUDIES AT LOUGH INE
229
V. DISTRIBUTION IN RELATION TO SHELTER AND
WAVE-EXPOSURE
A. INTRODUCTION
Most of the plant and animal species which are common in Lough Ine
show a significant preference for only part of the area; only a few occur
throughout. Many of these preferences appear to be related to wave
action; some species favour shelter, others exposure to waves, others an
intermediate condition. The information to be presented is based mainly
on a survey of the occurrence or abundance in July 1955 of a limited
number of common species at thirty-three stations, each extending 10 m
along the shore (Ebling et al., 1960). The whole intertidal region of each
station was searched, and the shallow sublittoral explored with a view
box, by wading, and in a few cases by diving. Observations of the sublittoral region did not a t any station extend below 5 m, and at some
stations not below 1-2 m; in most parts of the lough there is a thick
deposit of mud at greater depths.
We recognize that the distribution of organisms may fluctuate from
season to season or change over a period of time. For example, the
amount of Codium fragile within Lough Ine is not constant from year to
year; we noted slight differences between the years 1955 and 1958 in
the occurrence of Clawa squamata; and many new patches of Paracentrotus appeared in 1964. Nevertheless, our common experience over
many years in general confirms the conclusions based on the 1955 survey.
B. THE LITTORAL REGION
1. Species Preferring Open-sea Stat' 1 z m
Several intertidal organisms which occur on the open coast do not
penetrate the Bullock Narrows. Such are the alga Porphyra urnbi~icalis,
common on exposed shores where fucoids are absent, and the anemone
Actinia equina (Fig. 32); probably both require frequent splashing.
Littorina neritoides penetrates the mouth of Barloge Creek (Fig. 33).
The alga Lomentaria articulata (Fig. 34) penetrates as far as the Rapids,
and Laurencia pinnatijda as far as the South Basin of Lough Ine
(Fig. 35). Thais ( =Nucella) lapillus (Fig. 36) is abundant intertidally
on the open coast, but is found only in small numbers throughout
Barloge Creek and sparsely a t a few stations within the lough. Subject
to the occurrence of suitable food, its distribution appears to be largely
determined by predators; the problem is discussed in Section VII.
2. Species Preferring Intermediate Stations
Pucus serratus (Fig. 37) is absent both from the open coast and from
much of Lough Ine, but occurs throughout Barloge Creek and the
229
V. DISTRIBUTION IN RELATION TO SHELTER AND
WAVE-EXPOSURE
A. INTRODUCTION
Most of the plant and animal species which are common in Lough Ine
show a significant preference for only part of the area; only a few occur
throughout. Many of these preferences appear to be related to wave
action; some species favour shelter, others exposure to waves, others an
intermediate condition. The information to be presented is based mainly
on a survey of the occurrence or abundance in July 1955 of a limited
number of common species at thirty-three stations, each extending 10 m
along the shore (Ebling et al., 1960). The whole intertidal region of each
station was searched, and the shallow sublittoral explored with a view
box, by wading, and in a few cases by diving. Observations of the sublittoral region did not a t any station extend below 5 m, and at some
stations not below 1-2 m; in most parts of the lough there is a thick
deposit of mud at greater depths.
We recognize that the distribution of organisms may fluctuate from
season to season or change over a period of time. For example, the
amount of Codium fragile within Lough Ine is not constant from year to
year; we noted slight differences between the years 1955 and 1958 in
the occurrence of Clawa squamata; and many new patches of Paracentrotus appeared in 1964. Nevertheless, our common experience over
many years in general confirms the conclusions based on the 1955 survey.
B. THE LITTORAL REGION
1. Species Preferring Open-sea Stat' 1 z m
Several intertidal organisms which occur on the open coast do not
penetrate the Bullock Narrows. Such are the alga Porphyra urnbi~icalis,
common on exposed shores where fucoids are absent, and the anemone
Actinia equina (Fig. 32); probably both require frequent splashing.
Littorina neritoides penetrates the mouth of Barloge Creek (Fig. 33).
The alga Lomentaria articulata (Fig. 34) penetrates as far as the Rapids,
and Laurencia pinnatijda as far as the South Basin of Lough Ine
(Fig. 35). Thais ( =Nucella) lapillus (Fig. 36) is abundant intertidally
on the open coast, but is found only in small numbers throughout
Barloge Creek and sparsely a t a few stations within the lough. Subject
to the occurrence of suitable food, its distribution appears to be largely
determined by predators; the problem is discussed in Section VII.
2. Species Preferring Intermediate Stations
Pucus serratus (Fig. 37) is absent both from the open coast and from
much of Lough Ine, but occurs throughout Barloge Creek and the