Utility of Pop-Up Satellite Archival Tags to Study the Summer Dispersal and Habitat Occupancy of Dolly Varden in Arctic Alaska

In Arctic Alaska, Dolly Varden Salvelinus malma is highly valued as a subsistence fish; however, little is known about its marine ecology. New advances in electronic tagging, such as pop-up satellite archival tags (PSATs), provide scientists with a fishery-independent means of studying several aspects of this species’ movement and ecology. To evaluate the usefulness of this technology, we attached 52 PSATs to Dolly Varden in the Wulik River, which flows from northwestern Alaska into the Chukchi Sea, to study several characteristics of the marine habits of this species. Overall, PSATs provided unprecedented information about summer dispersal of Dolly Varden, including the first evidence of offshore dispersal in the Chukchi Sea, as well as previously documented dispersal types such as movement to other rivers and southerly nearshore movements in northwestern Alaska. On the basis of minimal observable evidence of tag-induced behavioral effects, as well as movements of more than 450 km by fish at liberty (i.e., between tag deployment and release or recapture), we conclude that PSATs offer an effective alternative method for studying several aspects of Dolly Varden dispersal and ecology in areas where it is not practical or feasible to capture these fish, such as coastal and offshore regions of Arctic Alaska

Distribution of vascular plant species in woodland patches of Ojców National Park (southern Poland) in relation to seed dispersal

<p>Plant diaspore dispersal is a fundamental process affecting the development of forest vegetation and its natural regeneration, especially with regard to typical woodland species, which spread slowly and form short-term soil seed banks. Most of these species have poor seed dispersal mechanisms, which is the major cause of their very slow expansion.</p><p>The following questions were asked: (<em><strong>i</strong></em>) is there a relationship between the age of a woodland and the presence of forest vascular plant species representing different seed dispersal types; (<em><strong>ii</strong></em>) how do the proportions change between species representing different seed dispersal types in relation to the age of woodland; (<em><strong>iii</strong></em>) what factors determine the presence of species representing a given seed dispersal type; (<em><strong>iv</strong></em>) which factors affect the presence and which ones influence the abundance of selected woodland species? A multiple regression models were developed based on data obtained from 144 woodland patches designated for the study. A probit regression analysis was performed for selected species exhibiting various seed dispersal models.</p><p>Woodland plants of all seed dispersal types show a significant relationship with the age of woodland, starting from the strongest linkage: anemochores, myrmecochores, endozoochores, epizoochores, barochores, autochores. As the woodland ages, the proportion of forest myrmecochores and anemochores grows, whilst the proportion of autochores, epizoochores and endozoochores shrinks. Results obtained indicate that the direct proximity of ancient woodland has a major effect on the occurrence of more poorly dispersing plants in recent woodlands, such as myrmecochores and heavy anemochores.</p>