Introduction to the Online Marine Macrofauna Handbook
Marine Ecological Surveys Ltd., in collaboration with MarLIN and DeepBlueSky, have developed the Marine Macrofauna Genus Trait Handbook as an online evolving resource for use by the marine science community and those scientists involved in the planning and implementation of aggregate licenses. The original handbook was intended to assist in the assessment of the impacts of marine aggregate dredging on benthic resources as well as in the prediction of the potential that individual genera have to recolonise and the time that may be required for restoration of the biomass by growth of the colonising individuals. The update has been published both as a website www.genustraithandbook.org.uk and as a Gardline Environmental Ltd. match funded iPhone App. The iPhone App is available as a free download and, once downloaded, is available offline thus enhancing its efficacy. Reciprocal links exist between the Marine Macrofauna Genus Trait Handbook website and the MarLIN Biological Traits Information Catalogue (BIOTIC) website.
Our knowledge of the biology and life-history of even the common invertebrates that characterise marine sands and gravels is surprisingly sparse. We have carried out a comprehensive search of the literature and have added information based on cohort analysis, growth ring data and estimated life-spans and body size data of the genera collected in our surveys. This has provided information on key traits that we consider to be important in controlling vulnerability to disturbance and subsequent recoverability of key characterising genera of marine sands and gravels in UK waters.
Out of a possible 25 traits, we have acceptable data for 6 traits rated as significant in predicting recoverability and for which a reasonable amount of data from both published sources and our own analyses were available. The traits were assigned a ‘score’ allowing an estimate of the relative vulnerability to disturbance and recoverability to be made. These traits are as follows:-
- Size - ranges from <1cm, 1-10cm, 10-20cm and >20cm.
- Adult Motility - ranges from sedentary to short-range mobility and to mobile adults.
- Larval Motility - 3 different larval modes:- brooded larvae, a short-term larval phase and a long larval phase
- Life-span - ranges from <1 year, 1-2 years, 2-10 years and >10 years.
- Age at reproductive maturity - ranges from <1 year, 1-2 years, 2-4 years and > 4 years.
- Fecundity - ranges from 1-10 eggs, 10-100, 100-1000, 1000-10,000 and 10,000-1 million eggs.
Note that some of the data span more than one category. Where there is insufficient information to assess a particular relevant trait, we have estimated the value from information for related genera. These values are shown in dotted outline in the traits diagrams to indicate an uncertainty in the value shown for a particular genus.
The information can then be used to estimate the likely time for restoration of BIODIVERSITY by recolonisation, and for subsequent restoration of BIOMASS following the growth of colonising individuals during the life-span of the particular genera encountered in the deposits. Basically, small organisms with a high fecundity and a short life-span are likely to have a higher recoverability compared with larger organisms with a long life-span and slower growth rate. Organisms with a long planktonic phase are likely to colonise rapidly from sources outside of a disturbed area compared with those with a short planktonic phase or which have no planktonic larval phase. Again, genera with mobile adults are likely to be able to accommodate sediment deposited by the dredging process, and may also have the potential for recolonisation by adults as well as juveniles.
Data suggest that ‘biodiversity’ based on the number of characterising taxa in marine deposits is related in a complex way to sediment type. The maximum number of characterising taxa is associated with mixed deposit types including sandy gravel, muddy sandy gravel, gravely sand, gravely muddy sand and cobbles. Once the characterising taxa have been defined for a particular deposit type, the vulnerability and recoverability of each of the characterising genera can then be identified. Provided that the substrate remains suitable for recolonisation following cessation of dredging, the rate of recolonisation and growth for a suite of genera can then be assembled for the characterising community identified in a particular survey site.
Some short-lived and fast growing components of the community that may have a long larval phase are likely to recolonise and grow to adult size in a short time, but other components including some of the larger molluscs may take several years to achieve successful settlement and several (or many) years before the biomass is restored by growth of the colonising individuals. The predicted restoration of biodiversity by recolonisation and of community structure by growth of the colonising organisms is thus likely to be sequential and heavily dependent on the nature of the deposits and resident community that occurs prior to dredging.
The references are grouped according to the information provided by them in relation to biology, taxonomy, distribution and reproduction of the genus, and are available in full at the click of a button. The banner on each page is colour coded according to the sediment type in which this genus is commonly found.
MESL have assumed responsibility for an ongoing update as part of their corporate responsibility and commitment to the marine aggregate industry. The project is intended to be an evolving facility which will enable a seamless upload of “additional” data and images as they become available thereby adding further tools in the enhancement, conservation and management of important habitat resources.
This online Marine Macrofauna Genus Trait Handbook Update, Project Ref: MEPF 10/P142, was funded by Defra through the Marine Aggregate Levy Sustainability Fund (MALSF) as an extension to the following project:-
Preparation and production of the original handbook was funded by Defra through the Marine Aggregate Levy Sustainability Fund (MALSF) as an extension to the following project:-
Marine Ecological Surveys Limited 2007. Predictive framework for assessment of recoverability of marine benthic communities following cessation of aggregate dredging. Technical Report to the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) and the Department for Environment, Food and Rural Affairs (Defra). Project No MEPF 04/02. Marine Ecological Surveys Limited, 24a Monmouth Place, BATH, BA1 2AY. pp. 115 + electronic appendices pp. 466.
The online Marine Macrofauna Genus Trait Handbook received match-funding from Gardline Environmental Limited to convert the material to an iPhone App.