Dear Marmam subscribers,
We are pleased to announce the publication of two articles on environmental niche modelling of cetaceans in the Azores (Central North Atlantic). Both articles are open access and can be downloaded directly from the respective journals’ webpages using the DOI links provided below. 1. Tobeña, M.*, Prieto, R.*, Machete, M., and Silva, M.A. (2016). Modeling the potential distribution and richness of cetaceans in the Azores from fisheries observer program data. Frontiers in Marine Science 3. doi: http://dx.doi.org/10.3389/fmars.2016.00202. * These authors have contributed equally to this work. Abstract: Marine spatial planning and ecological research call for high-resolution species distribution data. However, those data are still not available for most marine large vertebrates. The dynamic nature of oceanographic processes and the wide-ranging behavior of many marine vertebrates create further difficulties, as distribution data must incorporate both the spatial and temporal dimensions. Cetaceans play an essential role in structuring and maintaining marine ecosystems and face increasing threats from human activities. The Azores holds a high diversity of cetaceans but the information about spatial and temporal patterns of distribution for this marine megafauna group in the region is still very limited. To tackle this issue, we created monthly predictive cetacean distribution maps for spring and summer months, using data collected by the Azores Fisheries Observer Programme between 2004 and 2009. We then combined the individual predictive maps to obtain species richness maps for the same period. Our results reflect a great heterogeneity in distribution among species and within species among different months. This heterogeneity reflects a contrasting influence of oceanographic processes on the distribution of cetacean species. However, some persistent areas of increased species richness could also be identified from our results. We argue that policies aimed at effectively protecting cetaceans and their habitats must include the principle of dynamic ocean management coupled with other area-based management such as marine spatial planning. 2. Prieto, R.*, Tobeña, M.*, and Silva, M.A. (2016). Habitat preferences of baleen whales in a mid-latitude habitat. Deep Sea Research Part II: Topical Studies in Oceanography. doi: http://dx.doi.org/10.1016/j.dsr2.2016.07.015. * These authors have contributed equally to this work. Abstract: Understanding the dynamics of baleen whale distribution is essential to predict how environmental changes can affect their ecology and, in turn, ecosystem functioning. Recent work showed that mid-latitude habitats along migratory routes may play an important role on the feeding ecology of baleen whales. This study aimed to investigate the function of a mid-latitude habitat for blue (Balaenoptera musculus), fin (Balaenoptera physalus) and sei (Balaenoptera borealis) whales occurring in sympatry during spring and summer months and to what extent their environmental niches overlap. We addressed those questions by developing environmental niche models (ENM) for each species and then making pairwise comparisons of niche overlap and relative habitat patch importance among the three species. ENMs were created using sightings from the Azorean Fisheries Observer Program from May to November, between 2004 and 2009, and a set of 18 predictor environmental variables. We then assessed monthly (April–July) overlap among ENMs using a modified Hellinger׳s distance metric (I). Results show that the habitat niches of blue and fin whales are strongly influenced by primary productivity and sea surface temperature and are highly dynamic both spatially and temporally due to the oceanography of the region. Niche overlap analyses show that blue and fin whale environmental niches are similar and that the suitable habitats for the two species have high degree of spatial coincidence. These results in combination suggest that this habitat may function as a mid-latitude feeding ground to both species while conditions are adequate. The sei whale model, on the other hand, did not include variables considered to be proxies for prey distribution and little environmental niche overlap was found between this species and the other two. We argue that these results suggest that the region holds little importance as a foraging habitat for the sei whale. With the very best regards to all, Rui Prieto MARE – Marine and Environmental Sciences Centre; IMAR Centre at the University of the Azores 9901-862 Horta Portugal Tel: (351) 292200475 Fax: (351) 292200411 E-mail: rpri...@mare-centre.pt http://www.whales.uac.pt
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