Coastal winds and larval fish abundance indicate a recruitment mechanism for southeast Australian estuarine fisheries

Coastal winds transport water masses and larval fish onshore or offshore which may influence estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we combine datasets from a historical database of larval fish off southeast Australia with a high-resolution atmospheric reanalysis model to show that normalised abundance of coastally spawned larvae increased with weak to moderate upwelling favourable winds 14 days prior to sampling. The increase in abundance may reflect increased nutrient and plankton availability for larval fish. Normalised larval abundance decreased following strong upwelling favourable winds but increased after onshore (downwelling favourable) winds, due to wind-driven transport. By combining a commercial estuarine fisheries catch-rate dataset (4 species, 8 estuaries, 10 years) and the high-resolution atmospheric reanalysis model, we show that negative effects of upwelling favourable winds during the spawning period can be detected in lagged estuarine commercial fisheries catch rates (lagged by 2–8 years depending on species' growth rates), potentially representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may have reduced larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the southeast Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds.     

Woodland networks in a changing climate: Threats from land use change

Landscape adaptation to climate change requires policies that facilitate species dispersal, to counteract the effects of fragmentation and allow tracking of a species’ ‘climatic niche’. Expanding existing ecological networks is often proposed as a measure to maintain functional connectivity for forest species in multi-functional landscapes.In the next decades, however, such networks will be threatened by climate change through its effects on land use change, as global drivers are likely to have an increasing influence on national land use policy. Evaluation of indirect effects of climate change, on habitat networks, mediated by land use change, is therefore needed. We used an approach integrating climate, soil properties, and landscape resistance to dispersal, the latter estimated using Circuit Theory, to evaluate the vulnerability to land use change of forest habitat networks in Scotland, given two scenarios of land use change. In Scotland a combination of high food prices and improved land capability for agriculture could lead to decreased landscape connectivity for woodland species, especially in the East and South, with potentially large trade-offs between agriculture and woodland connectivity in the case of loss of woodland on prime agricultural land. We suggest that planning of ecological networks needs to account for future land use change. Adaptation and mitigation strategies across multiple sectors should be reconciled. Woodland networks will benefit from minimising creation of new woodlands on future prime agricultural land, the protection of existing patches, and the creation of wide-scale dispersal pathways along climatic gradients, i.e. in the N–S and E–W directions.     

Beyond predictions: biodiversity conservation in a changing climate

Climate change is predicted to become a major threat to biodiversity in the 21st century, but accurate predictions and effective solutions have proved difficult to formulate. Alarming predictions have come from a rather narrow methodological base, but a new, integrated science of climate-change biodiversity assessment is emerging, based on multiple sources and approaches. Drawing on evidence from paleoecological observations, recent phenological and microevolutionary responses, experiments, and computational models, we review the insights that different approaches bring to anticipating and managing the biodiversity consequences of climate change, including the extent of species' natural resilience. We introduce a framework that uses information from different sources to identify vulnerability and to support the design of conservation responses. Although much of the information reviewed is on species, our framework and conclusions are also applicable to ecosystems, habitats, ecological communities, and genetic diversity, whether terrestrial, marine, or fresh water.     

Long-distance signaling in nodulation directed by a CLAVATA1-like receptor kinase

Proliferation of legume nodule primordia is controlled by shoot-root signaling known as autoregulation of nodulation (AON). Mutants defective in AON show supernodulation and increased numbers of lateral roots. Here, we demonstrate that AON in soybean is controlled by the receptor-like protein kinase GmNARK (Glycine max nodule autoregulation receptor kinase), similar to Arabidopsis CLAVATA1 (CLV1). Whereas CLV1 functions in a protein complex controlling stem cell proliferation by short-distance signaling in shoot apices, GmNARK expression in the leaf has a major role in long-distance communication with nodule and lateral root primordia.     

The effect of male absence on the larval production of the spider crab Maja brachydactyla Balss, 1922

The spider crab Maja brachydactyla, Balss 1922 can produce three consecutive broods per breeding season in the wild, whereas females in captivity can spawn up to four times in the absence of males. The effect of male absence on the larval production of the spider crab M. brachydactyla was studied in a 2‐year experiment in which females were kept in captivity in the presence or absence of males. The broodstock were maintained under natural photoperiod conditions, temperature (18.5 ± 1.0°C) and salinity (34.8 ± 0.7 g L^?1). The number of larvae, and when possible, the dry weight and proximate biochemical composition of each larval batch were calculated and the data grouped seasonally. The larval production (P < 0.001) and protein content (P = 0.037) were significantly lower in the absence of males. However, considering that the larval production in male presence decreased due to the low female survival rate, particularly in the last part of the experiment, the presence of males should be managed to maintain a high larval production and condition without jeopardizing the survival of females. Therefore, we recommend keeping females segregated from males and transferring males to female tanks only to mate.     

Modelling the oceanic habitats of two pelagic species using recreational fisheries data

Defining the oceanic habitats of migratory marine species is important for both single species and ecosystem‐based fisheries management, particularly when the distribution of these habitats vary temporally. This can be achieved using species distribution models that include physical environmental predictors. In the present study, species distribution models that describe the seasonal habitats of two pelagic fish (dolphinfish, Coryphaena hippurus and yellowtail kingfish, Seriola lalandi), are developed using 19 yr of presence‐only data from a recreational angler‐based catch‐and‐release fishing programme. A Poisson point process model within a generalized additive modelling framework was used to determine the species distributions off the east coast of Australia as a function of several oceanographic covariates. This modelling framework uses presence‐only data to determine the intensity of fish (fish km^?2), rather than a probability of fish presence. Sea surface temperature (SST), sea level anomaly, SST frontal index and eddy kinetic energy were significant environmental predictors for both dolphinfish and kingfish distributions. Models for both species indicate a greater fish intensity off the east Australian coast during summer and autumn in response to the regional oceanography, namely shelf incursions by the East Australian Current. This study provides a framework for using presence‐only recreational fisheries data to create species distribution models that can contribute to the future dynamic spatial management of pelagic fisheries.