Guidelines for model adaptation: a study of the transferability of a general seagrass ecosystem DBN model

Ecological models are extensively and increasingly used in support of environmental policy and decision making. Dynamic Bayesian Networks (DBN) as a tool for conservation have been demonstrated to be a valuable tool for providing a systematic and intuitive approach to integrating data and other critical information to help guide the decision-making process. However, data for a new ecosystem are often sparse. In this case, a general DBN developed for similar ecosystems could be applicable, but this may require the adaptation of key elements of the network. The research presented in this paper focused on a case study to identify and implement guidelines for model adaptation. We adapted a general DBN of a seagrass ecosystem to a new location where nodes were similar, but the conditional probability tables varied. We focused on two species of seagrass (Zostera noltei and Z. marina) located in Arcachon Bay, France. Expert knowledge was used to complement peer-reviewed literature to identify which components needed adjustment including parameterisation and quantification of the model and desired outcomes. We adopted both linguistic labels and scenario-based elicitation to elicit from experts the conditional probabilities used to quantify the DBN. Following the proposed guidelines, the model structure of the DBN was retained, but the conditional probability tables were adapted for nodes that characterised the growth dynamics in Zostera spp. population located in Arcachon Bay, as well as the seasonal variation on their reproduction. Particular attention was paid to the light variable as it is a crucial driver of growth and physiology for seagrasses. Our guidelines provide a way to adapt a general DBN to specific ecosystems to maximise model reuse and minimise re-development effort. Especially important from a transferability perspective are guidelines for ecosystems with limited data, and how simulation and prior predictive approaches can be used in these contexts.

A revision of the French Telothelepodidae and Thelepodidae (Annelida, Terebelliformia), with descriptions of three species and first European record of a non-indigenous species

Telothelepodidae and Thelepodidae from French waters are revised based on material available in French marine stations and newly collected specimens. This work is the second part of the Spaghetti Project aiming to revise French species of “Spaghetti” worms. It describes three new species using both morphological and molecular tools: Streblosoma cabiochi n. sp., Streblosoma lindsayae n. sp. and Thelepus corsicanus n. sp. This study also permitted us to detect the presence of an Asiatic species, Thelepus japonicus, in Arcachon Bay and Normandy, introduced via oysters transfers. An identification key for European species of both families is also provided.

New records of Ericthonius didymus Krapp-Schickel, 2013 (Crustacea: Amphipoda: Ischyroceridae) in European waters with a focus in Arcachon Bay, France and key to Ericthonius species

The amphipod Ericthonius didymus Krapp-Schickel, 2013 is reported for the first time outside its type locality in European waters, from the French Atlantic coast and from the Azores, Portugal. In particular, a large population was recorded in Arcachon, France. Molecular analyses were made to confirm the validity of three closely related Ericthonius species: E. didymus, E. convexus and E. pugnax. An identification key is provided, distinguishing Ericthonius species into three groups, based on the presence or absence of stridulating ridges on coxa 2 and posterodistal lobe on basis of male pereopod 5.

Cheirocratus pseudosundevallii (Amphipoda, Cheirocratidae), a new species from Arcachon Bay, Bay of Biscay

An examination of some benthic amphipods belonging to the genus Cheirocratus from Arcachon Bay revealed that they exhibited a combination of morphological character states that distinguished them from all previously described Cheirocratus species. In the form of the gnathopods, Cheirocratus pseudosundevallii is very close to two other European species: C. sundevallii and C. intermedius. An actualized key to the species of Cheirocratus is provided.

Monocorophium acherusicum (Amphipoda, Corophiidae), a species commensal to Diogenidae in Arcachon Bay, Bay of Biscay

Hermit crabs are well-known to shelter many epibiotic, endobiotic or endolithic species in their shell, and examination of shells inhabited by hermit crabs in Arcachon Bay reveals the presence of several such species. Among them is the amphipod Monocorophium acherusicum, a species originally described from European waters and now known to be well distributed throughout the world, but not previously recorded to be commensal with hermit crabs, as reported herein.