The Marine Life Information Network

Temperature increase (local)

Benchmark. A 5°C increase in temperature for one month, or 2°C for one year. Further detail

Evidence

Phyllophora crispa is widely distributed on the coasts of the British Isles, except in the east of England. It is widely distributed in the east Atlantic with a northern limit in Iceland and a southern limit in North Africa but is also present in the Mediterranean and Black Sea (Newroth, 1971; Dixon & Irvine, 1977; Guiry & Guiry, 2015; Bunker et al., 2012). OBIS (2016) recorded Phyllophora crispa in waters of 8.5 to 14.5°C, although the derivation of the records is unclear. Kooistra et al. (1989) noted that it was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and completion were possible limiting factors. However, Gallon et al. (2014) reported that changes in red seaweed assemblages across Brittany were correlated with a 0.7°C increase in coastal water temperature over the prior twenty years. Species varied in their response but the occurrence of several species of red algae, including Phyllophora crispa, increased.  

Sensitivity assessment.  Phyllophora crispa is distributed to the north and south of the British Isles and, therefore, is probably tolerant of a long-term 2°C change in temperature for a year. It is also likely to tolerate a 5°C change in the short-term. Therefore, a resistance of High is suggested so that resilience is High (by default) and the biotope is assessed as Not sensitive at the benchmark level.  However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

Temperature decrease (local)

Benchmark. A 5°C decrease in temperature for one month, or 2°C for one year. Further detail

Evidence

Phyllophora crispa is widely distributed on the coasts of the British Isles, except in the east of England. It is widely distributed in the east Atlantic with a northern limit in Iceland and a southern limit in North Africa but is also present in the Mediterranean and Black Sea (Newroth, 1971; Dixon & Irvine, 1977; Guiry & Guiry, 2015; Bunker et al., 2012). OBIS (2016) recorded Phyllophora crispa in waters of 8.5 to 14.5°C, although the derivation of the records is unclear. Kooistra et al. (1989) noted that it was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and completion were possible limiting factors.

Sensitivity assessment.  Phyllophora crispa is distributed to the north and south of the British Isles and, therefore, is probably tolerant of a long-term 2°C change in temperature for a year. It is also likely to tolerate a 5°C change in the short-term. Therefore, a resistance of High is suggested so that resilience is High (by default) and the biotope is assessed as Not sensitive at the benchmark level.  However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

Salinity increase (local)

Benchmark. A increase in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Phyllophora crispa is recorded from shady places in the lower littoral, lower littoral pools and subtidally to ca 30m (Dixon & Irvine, 1977; Bunker et al., 20102). Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  Maximova (2013; summary only) reported that ‘morphological and biological changes’ in Phyllophora crispa from the Black Sea changed in experiments where the ‘normal’ salinity was raised from 18 ppt to 25, 32 and 39, but no further details were available.  OBIS (2016) recorded Phyllophora crispa in waters of 17.9 to 38 pps, although the derivation of the records is unclear.

Sensitivity assessment.  The presence of Phyllophora crispa in the lower intertidal suggests that it might be exposed to changes in salinity due to evaporation or rainfall but only for very short periods.  This biotope (KSwSS.Pcri) is only recorded from full salinity so that an increase in salinity at the benchmark level would expose the biotope to hypersaline conditions, for example from hypersaline effluents.  However, no evidence on which to base and assessment was found.

Salinity decrease (local)

Benchmark. A decrease in one MNCR salinity category above the usual range of the biotope or habitat. Further detail

Evidence

Phyllophora crispa is recorded from shady places in the lower littoral, lower littoral pools and subtidally to ca 30m (Dixon & Irvine, 1977; Bunker et al., 20102). Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  Maximova (2013; summary only) reported that ‘morphological and biological changes’ in Phyllophora crispa from the Black Sea changed in experiments where the ‘normal’ salinity was raised from 18 ppt to 25, 32 and 39, but no further details were available.  OBIS (2016) recorded Phyllophora crispa in waters of 17.9 to 38 pps, although the derivation of the records is unclear. A comparative study of salinity tolerances of macroalgae collected from North Zealand and the South Kattegat (Denmark) where salinity is 16 psu showed that species generally had a high tolerance (maintained more than half of photosynthetic capacity in short-term exposures of 4 days) to salinities lower than 3.7 psu. However, tolerances varied between species with Phyllophora pseudoceranoides exhibiting greater tolerance than Phycodrys rubens, which was the least resistant species tested (Larsen & Sand-Jensen, 2006).

Sensitivity assessment.  The presence of Phyllophora crispa in the lower intertidal suggests that it might be exposed to changes in salinity due to evaporation or rainfall but only for very short periods. This biotope (KSwSS.Pcri) is only recorded from full salinity so that a decrease in salinity at the benchmark level would expose the biotope to reduced salinity conditions (18-30 psu). The observations from the Black Sea, the South Kattegat and OBIS suggest that Phyllophora crispa could survive reduced salinity conditions but the biotope would probably experience a reduction in species richness and less resistant species left or were lost from the biotope. Therefore, a resistance of Medium is suggested. Resilience is probably High so that sensitivity is assessed as Low at the benchmark level. However, confidence in the assessed in Low as it is based on expert judgment and proxies for evidence.

Water flow (tidal current) changes (local)

Benchmark. A change in peak mean spring bed flow velocity of between 0.1 m/s to 0.2 m/s for more than one year. Further detail

Evidence

Phyllophora crispa was recorded from moderately strong to very weak tidal flow (Connor et al., 2004). It has been recorded to regenerate after erosion (Dixon & Irvine, 1977) while Molenaar & Breeman (1994) noted that Phyllophora pseudoceranoides exhibited annual growth and die back patterns where growth was removed annually by abrasion or water action.  However, this biotope is unusual because the very weak to weak tidal streams and very wave sheltered conditions allow Phyllophora crispa to grow abundantly on fine sediments (muddy sands and sandy muds).  It is presumably attached to small stones  within the sediment.  A significant increase in water flow may winnow away the mud surface or even remove the mud habitat and hence the biotope if prolonged. An increase of 0.2 m/s may begin to erode the mud surface where the site is already subject to flow (e.g. weak flow at the seabed), based on sediment erosion deposition curves (Wright, 2001). Therefore, an increase in water flow could result in the loss of the ‘loose-lying’ mat of Phyllophora crispa.  However, an increase of only 0.1-0.2 m/s may only affect example of the biotope already in weak flow, rather than very weak flow and a resistance of Low is suggested with Low confidence. Resilience is probably Medium so that sensitivity is assessed as Medium.

Emergence regime changes

Benchmark.  1) A change in the time covered or not covered by the sea for a period of ≥1 year or 2) an increase in relative sea level or decrease in high water level for ≥1 year. Further detail

Evidence

Changes in emergence are ‘Not relevant’ to this biotope, which is restricted to fully subtidal habitats. The pressure benchmark is relevant only to littoral and shallow sublittoral fringe biotopes.

Wave exposure changes (local)

Benchmark. A change in near shore significant wave height of >3% but <5% for more than one year. Further detail

Evidence

Phyllophora crispa was recorded from wave exposed to very wave sheltered sites (Connor et al., 2004). It has been recorded to regenerate after erosion (Dixon & Irvine, 1977) while Molenaar & Breeman (1994) noted that Phyllophora pseudoceranoides exhibited annual growth and die back patterns where growth was removed annually by abrasion or water action.  However, this biotope is unusual because the very weak to weak tidal streams and very wave sheltered conditions allow Phyllophora crispa to grow abundantly on fine sediments (muddy sands and sandy muds).  It is presumably attached to small stones within the sediment.  A further decrease in wave exposure is unlikely to affect the biotope. However, an increase in wave exposure is likely to remove the loose-lying mat of Phyllophora crispa but a 3-5% change in significant wave height (the benchmark) is unlikely to have a significant effect. Therefore, the biotope is probably Not sensitive (resistance and resilience are High) at the benchmark level. 

Transition elements & organo-metal contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Hydrocarbon & PAH contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Synthetic compound contamination

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed but evidence is presented where available.

Radionuclide contamination

Benchmark. An increase in 10µGy/h above background levels. Further detail

Evidence

No evidence was found

Introduction of other substances

Benchmark. Exposure of marine species or habitat to one or more relevant contaminants via uncontrolled releases or incidental spills. Further detail

Evidence

This pressure is Not assessed.

De-oxygenation

Benchmark. Exposure to dissolved oxygen concentration of less than or equal to 2 mg/l for one week (a change from WFD poor status to bad status). Further detail

Evidence

Kooistra et al. (1989) noted that Phyllophora crispa was limited to lower shore tide pools but concluded that temperature and salinity were not the limiting factors but that oxygenation and competition were possible limiting factors.  However, no direct evidence was found.

Nutrient enrichment

Benchmark. Compliance with WFD criteria for good status. Further detail

Evidence

‘Zernov’s Phyllophora field’ in the north-western Black Sea has undergone significant degradation between 1964 and 2004 due to eutrophication, resultant algal blooms and increased turbidity (BSC, 2008; Kostylev et al., 2010). The ‘field’ is composed of several species of Phyllophora including Phyllophora crispa. The Phyllophora field has remained but the abundance of the Phyllophora, the range of Phyllophora species, their age structure, the extent of the ‘field’, and the ecosystem of fish and other algae decreased or declined. Although the Black Sea is a unique environment, the results suggest that nutrient enrichment could affect the biotope and its associated community adversely.  Nevertheless, this biotope is considered to be 'Not sensitive' at the pressure benchmark that assumes compliance with good status as defined by the WFD.

Organic enrichment

Benchmark. A deposit of 100 gC/m²/yr. Further detail

Evidence

‘Zernov’s Phyllophora field’ in the north-western Black Sea has undergone significant degradation between 1964 and 2004 due to eutrophication, resultant algal blooms and increased turbidity (BSC, 2008; Kostylev et al., 2010). The ‘field’ is composed of several species of Phyllophora including Phyllophora crispa. The Phyllophora field has remained but the abundance of the Phyllophora, the range of Phyllophora species, their age structure, the extent of the ‘field’, and the ecosystem of fish and other algae decreased or declined.  It is unclear if the eutrophication in the Black Sea resulted from nutrients, organic loading, or both. Therefore, in the absence of clear evidence no assessment has been made.

Physical loss (to land or freshwater habitat)

Benchmark. A permanent loss of existing saline habitat within the site. Further detail

Evidence

All marine habitats and benthic species are considered to have a resistance of ‘None’ to this pressure and to be unable to recover from a permanent loss of habitat (resilience is ‘Very Low’).  Sensitivity within the direct spatial footprint of this pressure is, therefore ‘High’.  Although no specific evidence is described confidence in this assessment is ‘High’, due to the incontrovertible nature of this pressure.

Physical change (to another seabed type)

Benchmark. Permanent change from sedimentary or soft rock substrata to hard rock or artificial substrata or vice-versa. Further detail

Evidence

If sedimentary substrata were replaced with rock substrata the biotope would be lost, as it would not longer be a sedimentary habitat.

Sensitivity assessment. Resistance to the pressure is considered ’None‘, and resilience ’Very low‘ or ‘None’ (as the pressure represents a permanent change) and the sensitivity of this biotope is assessed as ’High’.

Physical change (to another sediment type)

Benchmark. Permanent change in one Folk class (based on UK SeaMap simplified classification). Further detail

Evidence

This biotope is recorded from sandy gravelly muds (Connor et al., 2004, sediment matrix). Phyllophora crispa is found on other substrata, including rock and other seaweeds. The low energy environment of the biotope, i.e. low water flow and wave sheltered conditions, determines the nature of the sediment. The muddy sediment is probably inhospitable to most other macroalgae so that Phyllophora can become abundant. A change in sediment from sand muddy gravels to gravel or mud may not affect the biotope adversely. Bunker et al. (2012) note that Phyllophora crispa thrives on rock subject to shell gravel. Therefore, in the very sheltered condition so of this biotope, the mat of Phyllophora would probably survive on gravel or on muds where enough stone for attachment remains. Therefore, the biotope is probably Not sensitive (resistance and resilience are High) at the benchmark level. 

Habitat structure changes - removal of substratum (extraction)

Benchmark. The extraction of substratum to 30 cm (where substratum includes sediments and soft rock but excludes hard bedrock). Further detail

Evidence

The biotope is an epifloral mat sitting on the surface of the sediment. Extraction of the sediment to any depth would result in removal of the Phyllophora mat from the affected area.  Therefore, a resistance of None is suggested. Resilience is probably Medium and sensitivity is assessed as Medium but with Low confidence due to the lack of any direct evidence.

Abrasion / disturbance of the surface of the substratum or seabed

Benchmark. Damage to surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Dixon & Irvine (1977) noted that Phyllophora crispa regenerates after erosion and animal grazing. Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour or animal grazing.  However, this biotope (KSwSS.Pcri) is an epifloral mat sitting on the surface of sediment; probably loosely attaché to small stones or shells in the sediment.  Any passing bottom gear is liable to remove the mat of Phyllophora. Therefore, a resistance of Low is suggested. Resilience is probably Medium so that the sensitivity is assessed as Medium at the benchmark level but with Low confidence due to the lack of any direct evidence.

Penetration or disturbance of the substratum subsurface

Benchmark. Damage to sub-surface features (e.g. species and physical structures within the habitat). Further detail

Evidence

Dixon & Irvine (1977) noted that Phyllophora crispa regenerates after erosion and animal grazing. Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour or animal grazing.  However, this biotope (KSwSS.Pcri) is an epifloral mat sitting on the surface of sediment; probably loosely attaché to small stones or shells in the sediment.  Any passing bottom gear is liable to remove the mat of Phyllophora. Therefore, a resistance of Low is suggested. Resilience is probably Medium so that the sensitivity is assessed as Medium at the benchmark level but with Low confidence due to the lack of any direct evidence.

Changes in suspended solids (water clarity)

Benchmark. A change in one rank on the WFD (Water Framework Directive) scale e.g. from clear to intermediate for one year. Further detail

Evidence

Red algae are shade tolerant macroalgae. Phyllophora crispa is particularly shade tolerant and is recorded a greater depths than many other red algae. For example, Smith & Jones (1970) reported that Phyllophora crispa grew at a greater depth (25 m) than other red algae examined on the west coast of Anglesey and Norton (1968) reported it at 33 m at St Mary’s Isles of Scilly. Norton et al. (1971) noted that Phyllophora crispa penetrated up to 15 m in a sea cave (Bullock Island Cave, near Lough Ine), although its growth was stunted at its limit into the cave. The degradation of ‘Zernov’s Phyllophora field’ in the north-western Black Sea was attributed to eutrophication, algal blooms and turbidity. All three species of Phyllophora present survived but their biomass was reduced by an order to magnitude (Kostylev et al., 2010).  Therefore, it is likely that an increase in turbidity due to suspended solids could result in a loss of a proportion of the population of Phyllophora crispa, especially in the deeper examples of the biotope and a resistance of Low is suggested. Resilience is probably Medium so that sensitivity is assessed as Medium.

Smothering and siltation rate changes (light)

Benchmark. ‘Light’ deposition of up to 5 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Airoldi (2003) identified a number of morphological, physiological and life history traits that conferred high levels of tolerance to sedimentation. For example, regeneration of upright fronds from a perennial basal crust resistant to burial and scour, calcified thalli, apical meristems, large reproductive outputs, lateral vegetative growth and slow growth rates (Airoldi, 2003). Algae with tough thalli are more resistant to sedimentation and scour (Pedersén & Snoeijs, 2001). Phyllophora crispa was reported to regenerate after erosion and animal grazing (Dixon & Irvine, 1977) and Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour.  However, in the wave sheltered, low energy conditions that typify this biotope any deposit of sediment is likely to remain and smother the biotope. 

Sensitivity assessment. Phyllophora crispa grows up to 15 cm in length, and could probably either protrude through 5 cm of deposited sediment or grow up through it.  Therefore, a resistance of High is suggested. Resilience is, therefore, High and the biotope is probably Not sensitive at the benchmark level.

Smothering and siltation rate changes (heavy)

Benchmark. ‘Heavy’ deposition of up to 30 cm of fine material added to the seabed in a single discrete event. Further detail

Evidence

Airoldi (2003) identified a number of morphological, physiological and life history traits that conferred high levels of tolerance to sedimentation. For example, regeneration of upright fronds from a perennial basal crust resistant to burial and scour, calcified thalli, apical meristems, large reproductive outputs, lateral vegetative growth and slow growth rates (Airoldi, 2003). Algae with tough thalli are more resistant to sedimentation and scour (Pedersén & Snoeijs, 2001). Phyllophora crispa was reported to regenerate after erosion and animal grazing (Dixon & Irvine, 1977) and Bunker et al. (2012) noted that it tolerated sediment cover and thrived in areas subject to shell gravel.  Both observations suggest that it can either resist or regrow from damage due to sediment scour.  However, in the wave sheltered, low energy conditions that typify this biotope any deposit of sediment is likely to remain and smother the biotope. 

Sensitivity assessment. Phyllophora crispa grows up to 15 cm in length and would be completely smothered by 30 cm of deposited sediment.  The sediment is likely to remain, and the plants will be removed from light and probably succumb to localise anoxia under the sediment. Therefore, a resistance of None is suggested. Resilience is probably Medium and the sensitivity is assessed as Medium benchmark level.

Litter

Benchmark. The introduction of man-made objects able to cause physical harm (surface, water column, seafloor or strandline). Further detail

Evidence

Not assessed.

Electromagnetic changes

Benchmark. A local electric field of 1 V/m or a local magnetic field of 10 µT. Further detail

Evidence

No evidence was found

Underwater noise changes

Benchmark. MSFD indicator levels (SEL or peak SPL) exceeded for 20% of days in a calendar year. Further detail

Evidence

Not relevant

Introduction of light or shading

Benchmark. A change in incident light via anthropogenic means. Further detail

Evidence

Red algae are shade tolerant macroalgae. Phyllophora crispa is particularly shade tolerant and is recorded a greater depths than many other red algae. For example, Smith & Jones (1970) reported that Phyllophora crispa grew at a greater depth (25 m) than other red algae examined on the west coast of Anglesey and Norton (1968) reported it at 33 m at St Mary’s Isles of Scilly. Norton et al. (1971) noted that Phyllophora crispa penetrated up to 15 m in a sea cave (Bullock Island Cave, near Lough Ine), although its growth was stunted at its limit into the cave. The degradation of ‘Zernov’s Phyllophora field’ in the north western Black Sea was attributed to eutrophication, algal blooms and turbidity. All three species of Phyllophora present survived but their biomass was reduced by an order to magnitude (Kostylev et al., 2010).  Therefore, shading by an artificial structure may reduce photosynthesis (depending on intensity and duration), and may reduce the abundance of algae, although Phyllophora will probably survive.  Therefore, a resistance of Medium is suggested, with a resilience of High and a sensitivity of Low. However, permanent shading may reduce the depth to which the biotope can grow, resulting in loss of deeper example of the biotope.  The biotope occurs below 5 m so that artificial lighting is unlikely to penetrate the water column enough to affect photosynthesis.

Barrier to species movement

Benchmark. A permanent or temporary barrier to species movement over ≥50% of water body width or a 10% change in tidal excursion. Further detail

Evidence

Not relevant

Death or injury by collision

Benchmark. Injury or mortality from collisions of biota with both static or moving structures due to 0.1% of tidal volume on an average tide, passing through an artificial structure. Further detail

Evidence

The pressure definition is not directly applicable to seabed biotopes so Not relevant has been recorded.  Collision via ship groundings or terrestrial vehicles is possible but the effects are probably similar to those of abrasion above.

Visual disturbance

Benchmark. The daily duration of transient visual cues exceeds 10% of the period of site occupancy by the feature. Further detail

Evidence

Not relevant

Genetic modification & translocation of indigenous species

Benchmark. Translocation of indigenous species or the introduction of genetically modified or genetically different populations of indigenous species that may result in changes in the genetic structure of local populations, hybridization, or change in community structure. Further detail

Evidence

No evidence was found of the translocation, breeding or species hybridization of the important characterizing species.

Introduction or spread of invasive non-indigenous species

Benchmark. The introduction of one or more invasive non-indigenous species (INIS). Further detail

Evidence

Bonnemaisonia hamifera (and the Trailliella-phase) is a non-native species introduced to the British Isles from Japan and first recorded in 1890 (Dixon & Irvine, 1977; Maggs & Stegenga, 1998; Gollasch, 2006).  It is thought to have been introduced by shipping or with shellfish and to have dispersed by drifting on water currents (Gollasch, 2006).  Bonnemaisonia hamifera (and the Trailliella-phase) has spread around the British Isles and Europe, into the Mediterranean and the Canary Isles and north to the Orkneys and the Norwegian coast (Lüning, 1990, Maggs & Stegenga, 1998; Gollasch, 2006).  It grows rapidly, reproduces vegetatively, and can spread by fragmentation and drifting (Maggs & Stegenga, 1998).

Bonnemaisonia hamifera (and the Trailliella-phase) occurs in this biotope with Phyllophora crispa but at a lower abundance than its characteristic biotope (KSwSS.Tra). KSwSS.Tra occurs in shallower waters but otherwise similar conditions. Therefore, if the abundance of Phyllophora crispa was reduced by an external factor then the Trailliella might be about to take over the available space, especially in the shallow examples of the biotope (KSwSS.Pcri). However, there is no evidence that this has happened to date.  Therefore, a precautionary resistance of Medium is suggested but with a ‘Low’ confidence. Resilience is probably High so that sensitivity is assessed as Low.

Introduction of microbial pathogens

Benchmark. The introduction of relevant microbial pathogens or metazoan disease vectors to an area where they are currently not present (e.g. Martelia refringens and Bonamia, Avian influenza virus, viral Haemorrhagic Septicaemia virus). Further detail

Evidence

No evidence was found.

Removal of target species

Benchmark. Removal of species targeted by fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Phyllophora crispa is unlikely to be targetted by any commercial or recreational fishery or harvest.

Removal of non-target species

Benchmark. Removal of features or incidental non-targeted catch (by-catch) through targeted fishery, shellfishery or harvesting at a commercial or recreational scale. Further detail

Evidence

Accidental physical disturbance due to access (e.g. trampling), grounding, or passing fishing gear is examined under abrasion above. However, the accidental removal of the Phyllophora mat would result in a significant change in the biological character of, and loss of, the biotope. Therefore, a resistance of None is suggested. Resilience is probably Medium so that sensitivity is assessed as Medium but with 'Low' confidence.