USPOREDBA BROJNOSTI PREDATORA I RAZNOLIKOSTI RIBA U ZAŠTIĆENIM PODRUČJIMA (NP KORNATI, HRVATSKA) I SUSJEDNIM PODRUČJIMA U KOJIMA JE DOZVOLJEN RIBOLOV

Fishing activities and other anthropogenic influences have direct and indirect effects on fish community structure. One expectation may be that with increasing fishing pressure and decreasing size selectivity of fisheries all predator populations decline and consequently fish assemblages change. Comparisons of MPAs with unprotected areas are considered valid natural experiments to test hypotheses on how predation structures communities. Here we report on the use of a lure-assisted visual census in the Central Croatian Adriatic to assess and compare fish assemblages in MPA sites (Kornati NP) with adjacent unprotected sites. We detected a significant protection effect on mesopredator abundance and overall fish diversity/richness and that protection status explained a significant portion of the fish assemblage variability, all independent of additional predictor variables, like habitat and depth. As we continue to expand the spatiotemporal scale and magnitude of the approach, we hope that it will eventually provide us with a long-term data series needed for testing many hypotheses in coastal ecology, including the effects of MPAs, coastal development, fishing and global climate change on the species interactions, abundance, diversity and assembly of animal species across multiple spatial scales.Ribolovne i druge antropogene aktivnosti izravno i neizravno utječu na sastav zajednica riba. Jedna od pretpostavki je da povećani ribolovni napor dovodi do smanjenja populacije predatorskih vrsta riba što dovodi do promjena u sastavu zajednica riba. Usporedba zaštićenih i nezaštićenih područja smatra se vjerodostojnom eksperimentalnom metodom za testiranje hipoteze na koji način struktura predatora utječe na zajednicu riba. Ovdje predstavljamo rezultate korištenja metode vizualnog cenzusa uz pomoć mamca na području srednjeg Jadrana kako bi procijenili i usporedili sastav zajednica riba u zaštićenom području (NP Kornati) i susjednim nezaštićenim područjima. Zabilježili smo značajan utjecaj zaštite na brojnost meso-predatora i na ukupnu raznolikost/brojnost riba kao i to da je zaštitom moguće objasniti značajan dio varijabilnosti u sastavu zajednica riba, neovisno o drugim faktorima poput tipa staništa ili dubine. Daljnjim proširivanjem naših istraživanja na prostornoj i vremenskoj skali, očekujemo da ćemo prikupiti vrijedne i dugotrajne podatke koji su potrebni kako bismo testirali mnoge pretpostavke u ekologiji priobalne zone, uključujući one o u utjecaju zaštićenih područja, razvoju obale, ribolovu, dostupnosti staništa te globalnim klimatskim promjenama na odnose među različitim vrstama, brojnost, raznolikost i sastav životinjskih vrsta na raznim prostornim skalama

Submerged Speleothemes - Expect the Unexpected. Examples from the Eastern Adriatic Coast (Croatia)

With the intention of reconstructing Late Pleistocene – Holocene sea-level changes along the Eastern Adriatic coast, a series of speleothems were collected from several submerged caves and pits, in order to constrain periods of their deposition and ceased growth related to sea-level fluctuations. For that purpose, stalagmites provide more reliable records than stalactites, due to their successive layers deposited perpendicularly to the growth direction. Therefore, stalagmites have been collected preferably. But, two of 17 speleothems displayed unexpected interior morphology – speleothem L-1 collected at the depth of 1.5 m in Medvjeđa spilja Cave on Lošinj Island, and speleothem M-25 from Pit near Iški Mrtovnjak Islet collected at the depth of 25 m. Both of the samples were taken from the cave floor, in the growth position of the stalagmite. But the insight into the perpendicular cut with evident central tube revealed their true (stalactitic) origin and additional confirmations were obtained by longitudinal cut and U-Th and 14C dating. Just as the causes of their breakdowns were probably different, so were their falls; speleothem M 25 (together with several other speleothems around it) stuck in the marine sediment in its primary position, while L-1 turned upside-down and even continued crystallizing during the lower sea level. These events are possible in the continental caves, as well. Evidently, it is much easier to recognize and avoid these problems in air-filled caves than in the submarine ones where the speleothems are almost always covered with marine overgrowth, which disguises their outer morphology. Additionally, the bases of the stalagmites are also sometimes covered with marine sediment, which makes correct estimation rather difficult

USPOREDBA BROJNOSTI PREDATORA I RAZNOLIKOSTI RIBA U ZAŠTIĆENIM PODRUČJIMA (NP KORNATI, HRVATSKA) I SUSJEDNIM PODRUČJIMA U KOJIMA JE DOZVOLJEN RIBOLOV

Fishing activities and other anthropogenic influences have direct and indirect effects on fish community structure. One expectation may be that with increasing fishing pressure and decreasing size selectivity of fisheries all predator populations decline and consequently fish assemblages change. Comparisons of MPAs with unprotected areas are considered valid natural experiments to test hypotheses on how predation structures communities. Here we report on the use of a lure-assisted visual census in the Central Croatian Adriatic to assess and compare fish assemblages in MPA sites (Kornati NP) with adjacent unprotected sites. We detected a significant protection effect on mesopredator abundance and overall fish diversity/richness and that protection status explained a significant portion of the fish assemblage variability, all independent of additional predictor variables, like habitat and depth. As we continue to expand the spatiotemporal scale and magnitude of the approach, we hope that it will eventually provide us with a long-term data series needed for testing many hypotheses in coastal ecology, including the effects of MPAs, coastal development, fishing and global climate change on the species interactions, abundance, diversity and assembly of animal species across multiple spatial scales.Ribolovne i druge antropogene aktivnosti izravno i neizravno utječu na sastav zajednica riba. Jedna od pretpostavki je da povećani ribolovni napor dovodi do smanjenja populacije predatorskih vrsta riba što dovodi do promjena u sastavu zajednica riba. Usporedba zaštićenih i nezaštićenih područja smatra se vjerodostojnom eksperimentalnom metodom za testiranje hipoteze na koji način struktura predatora utječe na zajednicu riba. Ovdje predstavljamo rezultate korištenja metode vizualnog cenzusa uz pomoć mamca na području srednjeg Jadrana kako bi procijenili i usporedili sastav zajednica riba u zaštićenom području (NP Kornati) i susjednim nezaštićenim područjima. Zabilježili smo značajan utjecaj zaštite na brojnost meso-predatora i na ukupnu raznolikost/brojnost riba kao i to da je zaštitom moguće objasniti značajan dio varijabilnosti u sastavu zajednica riba, neovisno o drugim faktorima poput tipa staništa ili dubine. Daljnjim proširivanjem naših istraživanja na prostornoj i vremenskoj skali, očekujemo da ćemo prikupiti vrijedne i dugotrajne podatke koji su potrebni kako bismo testirali mnoge pretpostavke u ekologiji priobalne zone, uključujući one o u utjecaju zaštićenih područja, razvoju obale, ribolovu, dostupnosti staništa te globalnim klimatskim promjenama na odnose među različitim vrstama, brojnost, raznolikost i sastav životinjskih vrsta na raznim prostornim skalama

Taksonomski sastav i sezonska raspodjela mikrofitoplanktona u estuariju rijeke Krke

Microphytoplankton taxonomic composition and cell density distribution were investigated at three representative stations along the highly stratified Krka River estuary on the eastern Adriatic coast. Samples were collected at approximately monthly intervals from March 1988 to April 1989. One hundred thirty six taxa were determined by light microscopy: 108 marine species (1 chrysophyte, 5 prymnesiophytes, 55 diatoms, 1 euglenophyte, 46 dinoflagellates) and 28 freshwater species (1 chrysophyte, 21 diatoms, 1 dinoflagellate, 3 chlorophytes, 2 cyanophytes). The seasonal distribution of microphytoplankton cell densities is influenced by the freshwater inflow through the Krka River and the ecological properties of the karstic salt-wedge-stratified estuary. Anthropogenic influence is notable in the lower reach of the estuary, around Šibenik.U radu je prikazan taksonomski sastav i raspodjela gustoće stanica mikrofitoplanktona na tri reprezentativne postaje u visoko stratificiranom estuariju rijeke Krke. Uzorci su sakupljeni u mjesečnim intervalima od ožujka 1988. do travnja 1989. godine. Svjetlosnim je mikroskopom određeno stotinu trideset i šest mikrofitoplanktonskih vrsta: 108 morskih (1 krizoficeja, 5 primnezioficeja, 55 dijatomeja, 1 euglenoficeja, 46 dinoflagelata) i 28 slatkovodnih vrsta (1 krizoficeja, 21 dijatomeja, 1 dinoflagelat, 3 kloroficeje, 2 cijanoficeje). Na sezonsku raspodjelu gustoće stanica mikrofitoplanktona utječe dotok vode rijeke Krke i ekološki uvjeti u estuariju. Utjecaj čovjeka vidljiv je u donjem dijelu estuarija, oko Šibenika

Draft Guidelines for Inventoring and Monitoring of Dark Habitats

UNEP(DEPI)/MED WG. 431/Inf.12Dark habitats1 are distributed throughout the Mediterranean basin from the sea surface (i.e. caves) to the deep-sea realm. Various habitats of unique scientific and conservation interest are included in this broad habitat category, such as dark caves, submarine canyons, seamounts and chemo-synthetic features supporting sensitive assemblages which require special protection. Therefore, dark habitats were considered under the Action Plan adopted in the Eighteenth Ordinary Meeting of the Contracting Parties to the Barcelona Convention (Turkey, December 2013). In the context of implementation schedule of the Dark Habitats Action Plan (UNEP-MAP-RAC/SPA, 2015a) a set of guidelines should be identified aiming to reduce the imminent pressures and threats affecting these vulnerable assemblages. This document aims to establish guidelines for inventorying and monitoring Mediterranean deep-sea habitats and marine caves in order to settle the basis for a regional-based assessment

COMPARING PREDATOR ABUNDANCE AND FISH DIVERSITY IN MPA SITES (KORNATI NP, CROATIA) AND ADJACENT SITES EXPLOITED BY FISHERIES

Fishing activities and other anthropogenic influences have direct and indirect effects on fish community structure. One expectation may be that with increasing fishing pressure and decreasing size selectivity of fisheries all predator populations decline and consequently fish assemblages change. Comparisons of MPAs with unprotected areas are considered valid natural experiments to test hypotheses on how predation structures communities. Here we report on the use of a lure-assisted visual census in the Central Croatian Adriatic to assess and compare fish assemblages in MPA sites (Kornati NP) with adjacent unprotected sites. We detected a significant protection effect on mesopredator abundance and overall fish diversity/richness and that protection status explained a significant portion of the fish assemblage variability, all independent of additional predictor variables, like habitat and depth. As we continue to expand the spatiotemporal scale and magnitude of the approach, we hope that it will eventually provide us with a long-term data series needed for testing many hypotheses in coastal ecology, including the effects of MPAs, coastal development, fishing and global climate change on the species interactions, abundance, diversity and assembly of animal species across multiple spatial scales

Error, Power, and Blind Sentinels: The Statistics of Seagrass Monitoring.

We derive statistical properties of standard methods for monitoring of habitat cover worldwide, and criticize them in the context of mandated seagrass monitoring programs, as exemplified by Posidonia oceanica in the Mediterranean Sea. We report the novel result that cartographic methods with non-trivial classification errors are generally incapable of reliably detecting habitat cover losses less than about 30 to 50%, and the field labor required to increase their precision can be orders of magnitude higher than that required to estimate habitat loss directly in a field campaign. We derive a universal utility threshold of classification error in habitat maps that represents the minimum habitat map accuracy above which direct methods are superior. Widespread government reliance on blind-sentinel methods for monitoring seafloor can obscure the gradual and currently ongoing losses of benthic resources until the time has long passed for meaningful management intervention. We find two classes of methods with very high statistical power for detecting small habitat cover losses: 1) fixed-plot direct methods, which are over 100 times as efficient as direct random-plot methods in a variable habitat mosaic; and 2) remote methods with very low classification error such as geospatial underwater videography, which is an emerging, low-cost, non-destructive method for documenting small changes at millimeter visual resolution. General adoption of these methods and their further development will require a fundamental cultural change in conservation and management bodies towards the recognition and promotion of requirements of minimal statistical power and precision in the development of international goals for monitoring these valuable resources and the ecological services they provide

Minimum detectable difference, random-plot design.

<p>Minimum detectable difference in habitat cover for the indicated number of random plots per monitoring event and power for detection of the difference in a two-sample, one-sided <i>t</i>-test, <i>α</i> = 0.05.</p

Threshold in classification error at which field labor is equalized for estimating 10% loss.

<p>Threshold in classification error at which field labor is equalized for direct versus map estimation of cover loss, for the indicated values of starting habitat cover (<i>α</i> = <i>β</i> = 0.05).</p