Jessica Goodheart

ABSTRACTAimUndersampling and other sources of sampling bias pose significant issues in marine macroecology, particularly when shaping conservation and management decisions. Yet, determining the extent to which such biases impact our understanding of marine diversity remains elusive. Here, utilising empirical data on sampling efforts, we sampled from virtually established species distributions to evaluate how deep is the influence of sampling bias on estimations of the latitudinal gradient in marine diversity.LocationAtlantic Ocean.Time PeriodPresent.Taxa StudiedOphiuroidea.MethodsWe developed a computer simulation that implements two null models of species distribution (the geometric constraints and the area model) in a two‐dimensional domain, replicates the latitudinal distribution of historical sampling efforts and then quantifies diversity metrics (observed and estimated species richness) and sample completeness for each grid cell and latitudinal band.ResultsWe found consistent patterns of observed species richness across models, noting peaks at midlatitudes regardless of whether the true richness was unimodal or flat. Dips in equatorial diversity persisted even after using different methods of species richness estimation. Additional simulations showed that estimators' accuracy improved with increased sampling efforts, but only when samples were randomly distributed. Spatially aggregated samples inflate completeness without necessarily enhancing estimators' accuracy.Main ConclusionsThis finding emphasises the imperative of bolstering sampling efforts at tropical latitudes and deploying robust statistical techniques to mitigate undersampling effects. Meanwhile, we suggest considering sampling bias as an alternative null hypothesis for recorded marine diversity patterns.

In the aftermath of the 2011 east Japanese earthquake and tsunami, anthropogenic debris from the east coast of Japan floated across the Pacific Ocean to the west coast of North America. One such vessel from Iwate Prefecture arrived on the coast of Oregon, and the fouling community included specimens identified as the nudibranch Hermissenda crassicornis, which was previously thought to range from Japan to Baja California but has since been split into three species: H. crassicornis (northeastern Pacific), H. opalescens (southeastern Pacific), and H. emurai (western Pacific). Also aboard were nudibranchs of the genera Dendronotus and Eubranchus. Previous work suggested that all of the motile invertebrates found in the tsunami debris fouling community were either pelagic or Japanese in origin. Our study sought to determine whether the Hermissenda nudibranch specimens collected from the Iwate vessel were, according to the most updated classification system, only H. emurai as would be the case if the nudibranchs were Japanese in origin. In addition, we also sought to identify the Dendronotus and Eubranchus aboard. Results from DNA sequencing and limited morphological analysis indicate that specimens of H. crassicornis, as it is currently recognized, and H. opalescens were found on the vessel. Morphological or genetic data resolved the other nudibranchs as the Eastern Pacific Dendronotus venustus and Eubranchus rustyus. These findings indicate that these species settled after arrival to the west coast of North America. Data shared on GBIF and the iNaturalist platform were also used to map where eastern Pacific Hermissenda are currently understood to occur.

Vulnerable marine ecosystems (VMEs) are protected from bottom-fishing impacts in international waters by UN resolutions through Regional Fishery Management Organizations. VMEs include deep-sea benthic taxa whose life-history traits make them vulnerable to disturbance. Conservation measures for VMEs require regulatory frameworks informed by biodiversity maps. Here we evaluate biogeographic patterns of VME biodiversity of the Southern Indian Ocean to understand conservation avenues for the Southern Indian Ocean Fisheries Agreement (SIOFA) management organization. We synthesised knowledge on the distribution of deep-sea benthic taxa and explored the quality and quantity of available data. Next, we explored how taxa are structured into bioregions using biogeographical networks. We found astounding Wallacean and Linnaean shortfalls within SIOFA's area, which is virtually devoid of distributional data. Across the entire area, results suggest that only 48 % of the expected deep-sea taxa has been sampled at most, and most sampled cells are inadequately sampled. Yet, our bioregionalization analysis identified multiple bioregions, some only observed within SIOFA's area. Whilst the Wallacean and Linnean shortfalls are so important for VMEs that they severely impede to make adequate maps for conservation planning, results suggest that SIOFA hosts a unique faunal composition that must be safeguarded. Predictive approaches to compensate for these shortfalls exist but will likely be insufficient and uncertain. Within SIOFA's area, there is no satisfying solution to cope with the data shortfalls. Yet, biodiversity maps are a global responsibility. This study makes a call to invest in biodiversity inventories in this region to promote informed conservation decisions.

While many studies predict changes in the distribution of individual species as a result of climate change, few studies have assessed such changes at the community level for aquatic invertebrates. We used ostracods (bivalved micro-crustaceans) to assess the effects of climate change on regional species richness, (re-) distribution and community composition across the river basins of the Southern Cone of South America. Using a range of niche-based models, we present projections of changes in diversity components in the light of two scenarios on increased carbon emissions: the moderate-optimistic (RCP 4.5) and the pessimistic (RCP 8.5) scenarios from four climate models on 2050 and 2080 scenarios. Future projections show increase in the number of (mapped) cells with a richness up to five species as compared to present-day situations. La Plata basin (LPLA) presents the highest species loss, mainly in the Paraguay and Paraná rivers, while the species gain occurred mainly in the La Puna Region, North Chile-Pacific Coast and southern LPLA basins. Global change might impact ostracod communities even on a medium term (2050). Despite losses of local species in all future scenarios, a small portion of the LPLA was identified as a potential future climatic refugia for ostracod communities, while the distribution area in Patagonia was predicted to be extremely small for some ostracods at the southernmost parts of South Argentina-South Atlantic Coast and South Chile-Pacific Coast basins in both futures. These results indicate that non-model organisms can also contribute greatly to formulate evidence-based management plans for aquatic ecosystems under climate change scenarios.

Understanding the status and abundance of species is essential for effective conservation decision-making. However, the availability of species data varies across space, taxonomic groups and data types. A case study was therefore conducted in a high biodiversity region—East Africa—to evaluate data biases, the factors influencing data availability, and the consequences for conservation. In each of the eleven target countries, priority animal species were identified as threatened species that are protected by national governments, international conventions or conservation NGOs. We assessed data gaps and biases in the IUCN Red List of Threatened Species, the Global Biodiversity Information Facility and the Living Planet Index. A survey of practitioners and decision makers was conducted to confirm and assess consequences of these biases on biodiversity conservation efforts. Our results showed data on species occurrence and population trends were available for a significantly higher proportion of vertebrates than invertebrates. We observed a geographical bias, with higher tourism income countries having more priority species and more species with data than lower tourism income countries. Conservationists surveyed felt that, of the 40 types of data investigated, those data that are most important to conservation projects are the most difficult to access. The main challenges to data accessibility are excessive expense, technological challenges, and a lack of resources to process and analyse data. With this information, practitioners and decision makers can prioritise how and where to fill gaps to improve data availability and use, and ensure biodiversity monitoring is improved and conservation impacts enhanced.

Many benthic invertebrate taxa possess planktonic early life stages which drift with water currents and contribute to dispersal of the species, sometimes reaching areas beyond the current ranges of the adults. Until recently, it had been difficult to identify planktonic larvae to species level due to lack of distinguishing features, preventing detection of expatriate species. Here we used DNA metabarcoding of the COI gene to obtain species-level identification of early life stages of benthic invertebrates in zooplankton samples from the Barents Sea and around Svalbard, where, regionally, large volumes of warm Atlantic Water enter the Arctic from the south. We compared the larval community in the water column to the adult community on the seafloor to identify mismatches. In addition, we implemented particle tracking analysis to identify the possible areas of origin of larvae. Our results show that 30–45% of larval taxa—largely polychaetes and nudibranchs—were not local to the sampling area, though most were found nearby in the Barents Sea. In the particle tracking analysis, some larvae originating along the Norwegian coast were capable of reaching the northwest coast of Svalbard within 3 mo, but larvae found east of Svalbard had a more constrained possible area of origin which did not extend to the Norwegian coast. This study highlights largely regional-scale larval connectivity in the Barents Sea but demonstrates the potential for some long-lived larval taxa to travel to Svalbard and the Barents Sea from further south.

Nudibranchs are charismatic marine gastropods that lack a shell in the adult stage. While most nudibranchs feed on sessile animals such as sponges, bryozoans, and cnidarians, the nudibranch genus Gymnodoris Stimpson, 1855 evolved a more active and predatory lifestyle, including sea slug predation, cannibalism, and oddly enough, fish-fin parasitism. At the beginning of our work, no phylogenetic hypothesis existed for the genus, nor a clear picture of how Gymnodoris is related to other nudibranchs. Here we set out to reconstruct Gymnodoris phylogeny, investigate species diversity, and clarify the status of the genus name Analogium, which had been proposed for members of the genus with a linear gill filament arrangement. We present the first phylogenetic hypothesis for Gymnodoris, reconstructed by maximum likelihood and Bayesian inference using two mitochondrial and two nuclear molecular markers, with gill filament arrangement plotted on the phylogeny. The backbone of the phylogeny remains unresolved with these markers, however, we found that Gymnodoris comprises three main well-supported clades, which we refer to as the “subornata”, “citrina” and “varied” clade, the latter two clades being comprised of several well-supported subclades. The sister group to Gymnodoris is a clade including the genera Vayssierea and Lecithophorus. Based on ABGD and PTP species delimitation methods, we conservatively estimate 65–70 species comprise our dataset. We further estimate that approximately 81% of the species we sampled are undescribed, and note that a linear gill filament arrangement has evolved multiple times within the genus. Gymnodoris is only monophyletic when the species with a linear gill arrangement are included. Therefore, at this time, we agree with the synonymy of Analogium striata with Gymnodoris striata by Rudman and Darvell (1990) and that the genus name Analogium is warranted as a junior synonym of Gymnodoris. Given the extensive undescribed diversity, and lack of resolution at some of the nodes in the phylogeny, patterns of diversification in diet are impossible to discern at this time and will require a large effort to both describe Gymnodoris species diversity and the diets of these candidate species.

The latitudinal gradient of increasing marine biodiversity from the poles to the tropics is one of the most conspicuous biological patterns in modern oceans.1, 2, 3 Low-latitude regions of the global ocean are often hotspots of animal biodiversity, yet they are set to be most critically affected b…

Phyllodocida is a clade of errantiate annelids characterized by having ventral sensory palps, anterior enlarged cirri, axial muscular proboscis, compound chaetae (if present) with a single ligament, and of lacking dorsolateral folds. Members of most families date back to the Carboniferous, although …

Human use of the land (for agriculture and settlements) has a substantial negative effect on biodiversity globally. However, not all species are adversely affected by land use, and indeed, some benefit from the creation of novel habitat. Geographically rare species may be more negatively affected by…