Spatio-temporal Dynamics of Population in Shanghai: A Case Study Based on Cell Phone Signaling Data

Abstract Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species affected the rank order of plots regarding richness of red-listed species, using two different national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the effect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation effectiveness over time than for more common species, and particularly at finer scales.

Download Full-text

Fishing for euros: how mapping applications can assist in maintaining revenues under the Landing Obligation

ICES Journal of Marine Science ◽

10.1093/icesjms/fsaa116 ◽

2020 ◽

Author(s):

Julia Calderwood ◽

Kristian Schreiber Plet-Hansen ◽

Clara Ulrich ◽

David G Reid

Keyword(s):

Temporal Dynamics ◽

Species Distributions ◽

Fishing Effort ◽

Fishing Industry ◽

Fishing Activity ◽

Spatio Temporal ◽

Catch Rates ◽

Demersal Species ◽

High Catch

Abstract With the introduction of the Landing Obligation (LO) in EU fisheries, there is an increasing need for fishers to avoid unwanted catches while maximizing revenues. Improving understanding of the spatio-temporal dynamics of unwanted catches could assist the fishing industry optimize catches by altering where they fish. How following such advice relates to revenues and fishery dynamics requires more consideration. We take an existing hotspot mapping methodology and examine how it could be used to identify fishing opportunities under the LO in Irish (Celtic Sea) and Danish (North Sea and Skagerrak) demersal fisheries. We consider if fishing effort can be relocated to avoid unwanted catches while maintaining revenues. The value per unit effort of fishing activity in both areas was often linked to high catch rates of key demersal species (cod, haddock, hake, and whiting). Our analyses indicated, however, that there are options to fish in areas that could provide higher revenues while avoiding below minimum conservation reference size catches and choke species. This was evident across both case study areas demonstrating that hotspot mapping tools could have wide applicability. There does, however, remain a need to explore how the displacement of vessels may further alter species distributions and fleet economics.

Download Full-text