Modelling the spatial abundance of a migratory predator: A call for transboundary marine protected areas

Identifying the natural reserve area of Cistanche salsa under the effects of multiple host plants and climate change conditions using a maximum entropy model in Xinjiang, China

Cistanche salsa (C. A. Mey.) G. Beck, a holoparasitic desert medicine plant with multiple hosts, is regarded as a potential future desert economic plant. However, as a result of excessive exploitation and poaching, its wild resources have become scarce. Thus, before developing its desert economic value, this plant has to be protected, and the identification of its natural reserve is currently the top priority. However, in previous nature reserve prediction studies, the influence of host plants has been overlooked, particularly in holoparasitic plants with multiple hosts. In this study, we sought to identify the conservation areas of wild C. salsa by considering multiple host-plant interactions and climate change conditions using the MaxEnt model. Additionally, a Principal Component Analysis (PCA) was used to reduce the autocorrelation between environmental variables. The effects of the natural distribution of the host plants in terms of natural distribution from the perspective of niche similarities and extrapolation detection were considered by filtering the most influential hosts: Krascheninnikovia ceratoides (Linnaeus), Gueldenstaedt, and Nitraria sibirica Pall. Additionally, the change trends in these hosts based on climate change conditions combined with the change trends in C. salsa were used to identify a core protection area of 126483.5 km². In this article, we corrected and tried to avoid some of the common mistakes found in species distribution models based on the findings of previous research and fully considered the effects of host plants for multiple-host holoparasitic plants to provide a new perspective on the prediction of holoparasitic plants and to provide scientific zoning for biodiversity conservation in desert ecosystems. This research will hopefully serve as a significant reference for decision-makers.

First assessment of floating marine litter abundance and distribution in the Bay of Biscay from an integrated ecosystem survey

In the Bay of Biscay, regional monitoring programmes and data on abundance and distribution of floating marine litter are scarce, contrary to many other European marine regions. Here, a joint analysis of multiyear observations (2017-2019) of floating micro and macrolitter and oceanographic conditions was conducted for the Bay of Biscay by combining microlitter samplings with neuston nets and vessel-based macrolitter observations. Results show spatiotemporal abundance and distribution patterns. The density of floating microlitter increased from 26,056 items/km² in 2017 to 1,802,4611 items/km² in 2019; floating macrolitter densities barely varied amongst year (2.52 items/km² in 2017 and 3.70 items/km² in 2019). No significant correlation was found between densities of micro and macrolitter, neither for the oceanographic variables. We conclude that longer micro and macrolitter monitoring periods and standardized datasets based on the cross-border cooperation are needed to collect more comparable information, evaluate trends, and support decision making in the area.

Predicting the distribution of foraging seabirds during a period of heightened environmental variability

Quantifying the links between the marine environment, prey occurrence, and predator distribution is the first step towards identifying areas of biological importance for marine spatial planning. Events such as marine heatwaves result in an anomalous change in the physical environment, which can lead to shifts in the structure, biomass, and distribution of lower trophic levels. As central-place foragers, seabirds are vulnerable to changes in their foraging grounds during the breeding season. We first quantified spatiotemporal variability in the occurrence and biomass of prey in response to an abrupt change in oceanography as a result of a marine heatwave event. Secondly, using multivariate techniques and machine learning, we investigated if differences in the foraging technique and prey of seabirds resulted in varying responses to changes in prey occurrence and the environment over a 2.5-yr period. We found that the main variables correlated with seabird distribution were also important in structuring the occurrence and biomass of prey; sea-surface temperature (SST), current speed, mixed-layer depth, and bathymetry. Both zooplankton biomass and the occurrence of fish schools exhibited negative relationships with temperature, and temperature was subsequently an important variable in determining seabird distribution. We were able to establish correlations between the distribution of prey and the spatiotemporal distribution of albatross, little penguins and common-diving petrels. We were unable to find a correlation between the distribution of prey and that of short-tailed shearwaters and fairy prions. For high-use coastal areas, the delineation of important foraging regions is essential to balance human use of an area with the needs of marine predators, particularly seabirds.

Spatial ecology of endangered roseate terns and foraging habitat suitability around a colony in the western North Atlantic

Predicting habitat suitability and understanding habitat utilization are important to inform and orient conservation and management decisions for the recovery of endangered species. In North America, the roseate tern Sterna dougallii is listed as endangered in both the northeastern USA and Canada, where little is known about the foraging spatial ecology of the species. We equipped breeding roseate terns with miniature GPS tracking devices during incubation at North Brother Island, the main Canadian colony. Our aim was to characterize the spatial foraging ecology of the species, identify marine zones of importance, and develop a habitat suitability model around the colony. Our results provide novel, high resolution information on individual foraging trips, notably showing that individuals restricted their range around the colony (15.4 km) while performing multiple foraging trips: up to 11 daytime trips and a maximum total of 152.9 km travelled per day. Roseate terns concentrated their foraging effort around the colony and further south along the coast to the Cockerwit Passage. Using distance from colony, sea surface temperature, distance from land, bathymetry, and subtidal substrate type as covariates in a habitat suitability model, a high proportion of the deviance was explained (72.4%); the model also predicted high occurrence of foraging near the colony, in Cockerwit Passage, and at additional sites to which the birds were not tracked. Along with the description of important marine areas for roseate terns nesting on North Brother Island, this habitat suitability model provides a relevant and essential context for understanding roseate tern habitat use in a broad sense, but with a focus on habitat requirements during incubation.

Of power and despair in cetacean conservation: estimation and detection of trend in abundance with noisy and short time-series

Many conservation instruments rely on detecting and estimating a population decline in a target species to take action. Trend estimation is difficult because of small sample size and relatively large uncertainty in abundance/density estimates of many wild populations of animals. Focusing on cetaceans, we performed a prospective analysis to estimate power, type-I, sign (type-S) and magnitude (type-M) error rates of detecting a decline in short time-series of abundance estimates with different signal-to-noise ratio. We contrasted results from both unregularized (classical) and regularized approaches. The latter allows to incorporate prior information when estimating a trend. Power to detect a statistically significant estimates was in general lower than 80%, except for large declines. The unregularized approach (status quo) had inflated type-I error rates and gave biased (either over- or under-) estimates of a trend. The regularized approach with a weakly-informative prior offered the best trade-off in terms of bias, statistical power, type-I, type-S and type-M error rates and confidence interval coverage. To facilitate timely conservation decisions, we recommend to use the regularized approach with a weakly-informative prior in the detection and estimation of trend with short and noisy time-series of abundance estimates.