A Wee Gem

Gem Anemone, Bunodactis verrucosa

The attractive Gem Anemone (Bunodactis verrucosa; also Aulactinia verrucosa) is a common inhabitant of well let rockpools and crevies. Its column bears lonitudinal rows of warts, from which its derives its alternative common name the Wartlet Anemone (1). Tentacles are in multiples of six, rarely being more than 48 giving a maximum span of 60 mm. Its wonderful hues of pink, green, red and brown are very appealing but, when combined with the transparency of parts of the tentacles, provide excellent camouflage against the background rockpool flora of encrusting corraline algae. While it reproduces by viviparity, asexual reproduction by budding has also been observed (2). B. verrucosa also has been shown to have excellent regenerative capabilities and has been used as a model to study coelenterate regeneration (3).

References:

1. Chinery 1999, A Beginner's Guide to Irelands Seashore p. 83
2. Perrin 1999, Oceanography and Marine Biology: an Annual Review 37 pp. 129–152
3. Shostak 1983, Development Genes and Evolution 190 pp. 274-282

Shooting the Teal

The Teal (Anas crecca) is Ireland's smallest duck (34 - 38 cm in length) most likely to be seen as a winter visitor from September to April, although there is a small breeding population in the country (1). An attractive little bird, the male has a dark brown head with a yellow bordered green patch through the eye, a grey body and a black edged, triangular patch in front of the black stern (2).

Male Teal, Anas crecca

The Teal is also attractive to hunting enthusiasts too, leading to a certain amount of lead shot in birds. A 21 year study of Teals in southern France showed that lead shot was more likely to be found embedded in male birds over females and there was an accumulation over time with no adverse effects (3). The same could not be said for lead found ingested in the gizzard of Teals. More likely to be found in females over males, as little as one piece of lead shot is toxic once ingested by foraging birds. Moreover, lead poisoning accumulates in ecosystems, with posioning being reported in in 17 higher predators in Europe such as the near threatened White Tailed Eagle of the endangered Spanish Imperial Eagle (5), strengthening calls for tighter regulation of lead shot usage.

References:

1. Sterry 2004, Collins Complete Guide to Irish Wildilfe p. 40
2. Hayman and Hume 2002, The New Birdwatcher's Pocket Guide to Britain and Europe p. 38
3. Guillemain 2007, Biological Conservation 137 pp. 567-576
4. Mateo 2009, Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans, Watson et al. eds. pp. 71-98

Sea Spleenwort Likes the Rain

Sea Spleenwort, Asplenium marinum

Sea Spleenwort, Asplenium marinum, is a common fern found in rock crevices through out the coasts of Ireland (1). As such, it is exposed to highly saline conditions which can delay spore germination and even prevent it completely at high concentrations (2). However, once a decrease in salt concentrations occurs, due in vivo to rainfall, spores regained their germination ability.

Sea Spleenwort, Asplenium marinum

References:

1. Philips 1980, Grasses, Ferns, Mosses and Lichens of Great Britain and Ireland p. 97
2. Pangua 2008, Flora - Morphology, Distribution, Functional Ecology of Plants 204 pp. 673-684

Trichoptera, the Caddisflies

Black Dancer Caddisfly, Mystacides azurea

The Caddisflies, or Trichoptera, are present in large number on every continent bar Antartica but are relatively unknown to the general public. Outside experts, anglers are the only people who know the insects. Caddisflies are a very important food for predators such as fish and anglers imitate them with artificial lures (1). Ignorance of these small (the largest being c. 30mm (2)) insects is understandable as they are tied to water for most of their lives. The eggs, larvae and pupae are found in or very near fresh water and the adults, while aerial, are rarely found far from streams and rivers (1). It is surprising therefore to discover that surveys of streams often see more species of caddisfly than mayflies, dragon- and damsel flies and stoneflies (3). Indeed in Ireland there are more species of caddisfly, 147, than of the other three orders combined, 100 (4).

Caddisfly Larval Cases

The diversity of caddisflies has been attributed to the ecological opportunities made possible by the secretion of silk (3). Silk is used by caddisflies for a variety of uses, such as spinning catching nets and hiding tubes, construction of small domes from sand grains,using silk to stick together pieces of plants and other materials into protective cases and the spinning of cocoons (5). Such activities are carried out prior to the emergence of the adults that resemble small moths, to which they are closely related (1). They differ in that their wings are covered with hairs rather than scales (6). The diversity of caddisflies is such that they are used in palaeoecology to investigate phenomenon such as the effect of long term climate change (7).

References:

1. Morse 2009, Trichoptera (Caddisflies) in Encyclopedia of Insects pp. 1015-1020
2. Chinery 1997, Collins Gem Insects p. 212
3. Mackay 1979, Annual Review of Entomology 24 pp. 185-208
4. Ferriss et al. 2009, Irish Biodiversity: A Taxonomic Inventory of Fauna pp. 96-111
5. Sehnal and Sutherland 2008, Prion 2 pp. 145-153
6. Holzenthal 2009, Encyclopedia of Inland Waters pp. 456-467
7. Williams 1988, Palaeogeography, Palaeoclimatology, Palaeoecology 62 pp. 493-500

River Builders

Flowers of the Branched Bur Reed, Sparganium erectum

Riverside plants have long been recognised for their ability to provide food and shelter for a range of animals – overhanging willows create ideal nesting sites for Moorhens, Water Mint and the many flowered Purple Loosestrife, among others, provide a food source for insects. It is now recognised that riverside vegetation does more than just influence species composition. They directly engineer landform development along river margins. For example by trapping sediment plants can change the unit stream power (1). In some cases, when trees are involved, this can lead to the creation of river islands (2).

Branched Bur Reed, Sparganium erectum

However it is not just trees that are capable of engineering rivers. The Branched Bur Reed (Sparganium erectum) is an emergent, sedge like perennial of still and slow moving fresh water and is common in northern temperate areas (3). It is currently being assessed for its ability to accelerate channel adjustment in low energy river systems (4). The plant acts by retaining finer sediment, organic matter and plant propagules which is held in place as the plant grows. This then allows the plant propagules to germinate, leading to the appearance of new species, which in turn promotes further retaining of sediment, resulting in landform construction.

Fruit of Branched Bur Reed, Sparganium erectum

References:

1. Gurnell et al. 2010, Geomorphology 116 pp. 135-144
2. Gurnell and Petts 2006, Earth Surface Processes and Landforms 31 pp. 1558–1574
3. Sterry 2004, Collins Complete Guide to Irish Wildilfe p. 270
4. Gurnell et al. 2010 Geophysical Research Abstracts 12 EGU2010-5883

Bacterial Associations of Cladonia pyxidata

Cladonia pyxidata

Lichens are a wonderful example of symbiosis in nature, often quoted to biology students as a relationship where both partners benefit from a very close association. However there may be more than just the two partners in these marriages of fungi and algae. Analysis of bacterial communities on lichen thalli found species that may provide nitrogenous compounds to the lichen and may even help protect the lichen (1). The lichen Cladonia pyxidata, found in degraded, peaty habitats (2), was found to have Burkholderia spp. on its thalus, bacteria that have been shown to have antifungal properties. This may provide some degree of protection to C. pyxidata.

References:

1. Cardinale et al. 2006, FEMS Microbiology Ecology 57 pp. 484–495
2. Aptroot et al. 2001, The Lichenologist 33 pp. 271-283

A Warm Spring Suits the Greenshank

Greenshank, Tringa nebularia

The Greenshank (Tringa nebularia) is a winter migrant to Ireland, arriving in September to estuaries all along the coast and returning to Scandinavia and Scotland in April (1). The individual pictured is showing its winter colours; in the summer they have a grey breast and darker above (2). The breeding performance of this species of sandpiper is very much influenced by weather conditions. In a 19 year study on a population of Scottish Greenshank, it was seen that, among other observations, warmer weather in the early spring resulted in larger eggs and heavier chicks, as well as more successful hatchings (3). Bad conditions over two successive years resulted in fewer birds returning to bread and the establishment of fewer new territories.

Greenshank, Tringa nebularia

References:

1. Nethersole-Thompson and Nethersole-Thompson 1979, Greenshanks
2. Hayman and Hume 2002, The New Birdwatcher's Pocket Guide to Britain and Europe p. 106
3. Thompson et al. 1986, Journal of Animal Ecology 55 pp. 181-199