69 research outputs found
Izbor staniŔta sekundarnih dupljaŔica u poplavnim nizinskim Ŕumama uz rijeku Dravu u Hrvatskoj
The correlation between secondary hole-nesters community characteristics and floristic and structural characteristics of their habitat was studied in riverine forest stands near river Drava in Croatia. Standard point count method was used for bird community sampling and circular plot method for habitat sampling. Sampling was carried out on 66 points. PCA analysis that included 28 independent habitat variables was used, followed by Spearman rank correlation between principal component scores and bird community variables (number of species and number of pairs). Tree basal area was used as an indication of stand maturity and to classify studied points into four forest types (ash, poplar, alder and mixed). Eight secondary hole-nesting species and 14 tree species were recorded. The average forest age was 59.8 Ā± 20.5 years, with ash and mixed stands being on average older than alder and poplar stands. Shannon-Wiener index of secondary hole-nesters diversity was highest in stands with dominant ash and was increasing with stand maturity. A significant positive correlation was found between number of bird species as well as number of pairs and older stands with lower number of tree species and lower relative number of poplar and alder. It can be concluded that diversity of secondary hole-nesting bird species as well as their abundance is correlated with structural habitat characteristics and that older stands show greater bird biodiversity and abundance.Korelacija izmeÄu karakteristika zajednica sekundarnih dupljaÅ”ica te floristiÄkih i strukturalnih karakteristika staniÅ”ta istražena je u nizinskim poplavnim Å”umama uz rijeku Dravu u Hrvatskoj. Standardna metoda prebrojavanja u toÄki koriÅ”tena je za istraživanje zajednica ptica, a metoda kružnih ploha za istraživanje staniÅ”ta. Mjerenja su provedena na ukupno 66 toÄaka. KoriÅ”tena je analiza primarnih komponenti sa 28 varijabli staniÅ”ta te Spearman rank korelacija izmeÄu skorova primarnih komponenti i varijabli zajednica ptica (broj vrsta i broj parova). Bazalna povrÅ”ina stabala koriÅ”tena je kao indikator starosti, ali i za klasifikaciju istraživanih toÄaka u Äetiri skupine (sastojine jasena, topole, johe i mijeÅ”ane sastojine). Zabilježeno je ukupno osam vrsta sekundarnih dupljaÅ”ica i 14 vrsta drveÄa. ProsjeÄna starost istraživanih toÄaka bila je 59,8 Ā± 20,5 godina. Sastojine jasena i mijeÅ”ane sastojine u prosjeku su bile starije od sastojina johe i topole. Shannon-Wiener indeks raznolikosti bio je veÄi u sastojinama s dominantnim jasenom i poveÄavao se sa starosti Å”ume. ZnaÄajna pozitivna korelacija dobivena je izmeÄu broja vrsta te brojnosti ptica i starijih sastojina s manjim brojem vrsta drveÄa i manjim relativnim brojem jedinki topole i johe. Možemo zakljuÄiti da sastav zajednica sekundarnih dupljaÅ”ica u nizinskim poplavnim Å”umama ovisi o strukturnim karakteristikama Å”uma, pri Äemu stare sastojine pokazuju veÄu brojnost i raznolikost
Disperzija bijele rode Ciconia ciconia u Parku prirode Lonjsko polje, Hrvatska
Dispersal of the White Stork Ciconia ciconia in the Lonjsko polje Nature Park, Croatia
There are two main types of dispersal: natal and reproductive. Natal dispersal is more common and individuals travel a greater distance than during reproductive dispersal. Direction and distances depend on various factors. Dispersal of the White Storks, Ciconia ciconia, was analysed using resightings of colour-ringed individuals in the Lonjsko polje Nature Park, Croatia. 36.7% observed individuals did not disperse outside the natal settlement, while only 14.3% covered a distance longer than 50 km. The median dispersal distance was 4.21 km (IQR = 0 - 8.8, n = 49); the correlation of dispersion with the number of nests in settlements and the size of the settlements was studied. Results have shown that storks are dispersing from settlements with a small number of nest to settlements with a large number of nests and that dispersal does not depend on the size of the settlement.Postoje dva tipa disperzije: natalna i reproduktivna. Natalna disperzija je ÄeÅ”Äa i jedinke prelaze puno veÄe udaljenosti nego tijekom reprodukcijske disperzije. Smjer i udaljenost na kojoj jedinka disperzira ovisi o gustoÄi populacije, kvaliteti staniÅ”ta, spolu, vjerojatnosti parenja u srodstvu ili dominantnosti drugih jedinki. Jedinke mnogih vrsta su vjerne mjestu gniježÄenja, stoga reproduktivna disperzija nije Äesta i najÄeÅ”Äe se odvija nakon slabog reprodukcijskog uspjeha ili gubitka partnera. Roda je ptica selica i redovita gnjezdarica u Hrvatskoj. Istraživana je disperzija bijele rode Ciconia ciconia u Parku prirode Lonjsko polje. Analizom nalaza roda oznaÄenih prstenovima u boji, utvrÄena je koliko je zastupljena natalna disperzija u odnosu na reproduktivnu te postoji li utjecaj brojnosti gnijezda u naseljima te veliÄine naselja na udaljenost i smjer disperzije. 36.7% jedinki nije disperziralo izvan naselja u kojem se izleglo, dok je samo 14.3% preÅ”lo udaljenosti veÄe od 50 km. Te su ptice naÄene u istoÄnoj Hrvatskoj, Austriji i MaÄarskoj. Srednja udaljenost disperzije bila je 4,21 km (IQR = 0 ā 8,8, n = 49). Rezultati su pokazali da rode natalnom disperzijom odlaze iz naselja s malim u naselja s velikim brojem gnijezda Å”to indicira da su socijalno privuÄene drugim jedinkama te da disperzija ne ovisi o veliÄini naselja (odnosno raspoloživom prostoru za gniježÄenje)
Dictionary of Croatian bird names
RjeÄnik standardnih hrvatskih ptiÄjih naziva s 11.308 vrsta i podvrsta, ureÄen prema BirdLife 2018 taksonomiji može se preuzeti na stranici: http://info.hazu.hr/hr/oakademiji/jedinice/zavod_za_ornitologiju/nazivlje/The dictionary of Croatian bird names with 11,308 species and subspecies, following BirdLife 2018 taxonomy can be downloaded from the webpage: http://info.hazu.hr/hr/oakademiji/jedinice/zavod_za_ornitologiju/nazivlje
Application of 2D-correlation UV/VIS spectroscopy for detection of color additives in fruit juices
U radu je istražena primjena 2D-korelacijske spektroskopije za detekciju umjetnih bojila u voÄnim sokovima crnog ribiza. Spektrofotometrijski su snimani uzorci soka, bojila i soka sa dodatkom bojila u podruÄju pH vrijednosti od 3,5 do 5,0 s rezolucijom od 1 nm u podruÄju valnih duljina od 400 do 700 nm. Dobiveni spektri su filtrirani Savitzky-Golayevom metodom, derivirani i koriÅ”teni za izradu sinkronih i asinkronih korelacijskih mapa. Usporedbom dobivenih korelacijskih mapa u podruÄju valnih duljina veÄih od 530 nm mogu se jasno detektirati spektalne promjene uzrokovane dodatkom umjetnog bojila u sok.This work explores the application of 2D-correlation spectroscopy for the detection of color additives in fruit juices of black currant. The samples of juice, azo-dyes and juice with azo-dyeswere spectroscopically examined in the pH range from 3.5 to 5.0, with a resolution of 1 nm in the wavelength range from 400 to 700 nm. Collected spectra were smoothed by the Savitzky-Golay method, numerically derived and employed for calculation of synchronous and asynchronous correlation maps. Spectral changes caused by the addition of azo-dyes to the juice can be clearly detected by comparing the obtained correlation maps in the wavelength range greater than 530 nm
Rare Birds in Croatia (2nd Report of Croatian Rarities Committee)
The second report of the Croatian Rarities Committee presents 37 records of rare birds received after 2002. Four species and one subspecies: Western Reef-egret Egretta garzetta gullaris, Bewickās Swan Cygnus columbianus, Terek Sandpiper Xenus cinereus,
Ring-billed Gull Larus delawarensis and Yellow-browed Warbler Phylloscopus inornatus were added to the list of Croatian birds and one, Arctic Redpoll Acanthis hornemanni was omitted, giving the total number of 381 bird species recorded in Croatia. Two species, White-billed Diver Gavia adamsii and Little Bustard Tetrax tetrax were observed for the first time in last 50 years. The list of rare species now includes 50 species. Checklist of bird species is given in the Appendix of this Report
Application of 2D-correlation UV/VIS spectroscopy for detection of color additives in fruit juices
U radu je istražena primjena 2D-korelacijske spektroskopije za detekciju umjetnih bojila u voÄnim sokovima crnog ribiza. Spektrofotometrijski su snimani uzorci soka, bojila i soka sa dodatkom bojila u podruÄju pH vrijednosti od 3,5 do 5,0 s rezolucijom od 1 nm u podruÄju valnih duljina od 400 do 700 nm. Dobiveni spektri su filtrirani Savitzky-Golayevom metodom, derivirani i koriÅ”teni za izradu sinkronih i asinkronih korelacijskih mapa. Usporedbom dobivenih korelacijskih mapa u podruÄju valnih duljina veÄih od 530 nm mogu se jasno detektirati spektalne promjene uzrokovane dodatkom umjetnog bojila u sok.This work explores the application of 2D-correlation spectroscopy for the detection of color additives in fruit juices of black currant. The samples of juice, azo-dyes and juice with azo-dyeswere spectroscopically examined in the pH range from 3.5 to 5.0, with a resolution of 1 nm in the wavelength range from 400 to 700 nm. Collected spectra were smoothed by the Savitzky-Golay method, numerically derived and employed for calculation of synchronous and asynchronous correlation maps. Spectral changes caused by the addition of azo-dyes to the juice can be clearly detected by comparing the obtained correlation maps in the wavelength range greater than 530 nm
Izbor staniÅ”ta i sliÄnosti zajednica ptica pjevica u Å”umama parkova prirode Medvednica i Žumberak ā Samoborsko gorje
The effect of floristic and structural characteristics of vegetation on the forest songbird communities in two Nature Parks: Medvednica andŽumberak ā Samoborsko gorje was studied. The point-count method was used for analyzing songbird communities and circular plot method for habitat mapping, on 101 points at both sites. Non-parametric test were used (Kruskalā Wallis and Kendal Tau). The tree basal area was used to classify studied points into five forest types (beech, oak, mixed deciduous, coniferous and mixed coniferous forests) and as indication of the stand maturity. The total of27 and 32 songbird species were recorded on Medvednica and Žumberak āSamoborsko gorje respectively. Diversity was higher on Žumberak ā Samoborsko gorje due to greater habitat fragmentation, while population density of songbirds was greater on Medvednica. Among structural characteristics, those related to forest age (average tree basal area and number of the small trees) had the most pronounced effect to the total songbird density and densities of different ecological groups of birds. Sorensen index showed that in spite of the differences in floristic composition between particular forest types in two studied areas (0.475 Ā± 0.120), songbird communities showed high similarity (0.872 Ā± 0.070). The highest similarity of songbird communities between Parks was recorded in beech and oak stands. Oak stands showed the lowest similarity in tree species composition and no significant difference in structural characteristics, while beech stands had many different structural features and several differences in densities of ecological groups of birds. The greatest difference of bird densities in the particular forest type between two Parks was found in beech and mixed coniferous stands. High structural differences between these two forests were the result of the forest age; bird populations had higher densities in older stands.Istraživanja zajednica ptica pjevica Å”umskih staniÅ”ta ukazuju da na njihovu strukturu i gustoÄu populacija mogu utjecati floristiÄka i strukturalna svojstva vegetacije. U ovom istraživanju željeli smo, usporedbom zajednica ptica Å”umskih staniÅ”ta dvaju parkova prirode, utvrditi utjecaj floristiÄkih i strukturalnih svojstava vegetacije na zajednicu ptica gnjezdarica. Istraživanje je provedeno tijekom 2006. i 2007. u Parkovima prirode Medvednica i Žumberak ā Samoborsko gorje. Å ume pokrivaju oko 60 % povrÅ”ineu oba parka, ali su kontinuirane na Medvednici i neÅ”to rascjepkanije na Žumberku. Istraživanje ptica provedeno je metodom prebrojavanja u toÄki, a uzorkovanje staniÅ”ta metodom kružnih ploha. Istraživanje je provedeno na ukupno101 toÄki: 49 na Medvednici i 52 na Žumberku. Pri statistiÄkoj obradi koriÅ”teni su neparametrijski testovi (KruskalāWallis i Kendal Tau). Udio temeljnice stabala koriÅ”ten je za odreÄivanje pripadnosti pojedinom Å”umskim tipu: bukovoj, hrastovoj, mjeÅ”ovitoj listopadnoj i mjeÅ”ovitoj crnogoriÄnoj Å”umi. ProsjeÄna temeljnica stabla koriÅ”tena je kao indikator starosti Å”ume. Istraživanjem je zabilježeno ukupno 27 vrsta ptica pjevica u Å”umama Medvednice i32 na Žumberku (Tablica 1). Å est vrsta ptica bilo je vezano uz odreÄeni tip Å”ume, s viÅ”e od 40 % parova zabilježenih u tom Å”umskom tipu. Diverzitet vrstabio je viÅ”i na Žumberku, dok je gustoÄa populacija ptica pjevica bila veÄa na Medvednici (Slika 2). Sorensenov indeks pokazao je da zajednice ptica istog tipa Å”ume izmeÄu dva podruÄja pokazuju znatno veÄu sliÄnost nego floristiÄki sastav (Slika 3). NajveÄa sliÄnost u zajednicama ptica izmeÄu dva Parka zabilježena je u bukovim i hrastovim sastojinama. Hrastove sastojine pokazuju najmanju floristiÄku sliÄnost, ali nemaju znaÄajnih razlika u strukturalnim svojstvima niti u ekoloÅ”kim skupinama ptica. Bukove sastojine naprotiv pokazuju znaÄajne strukturalne razlike i u njima je, kao i u mjeÅ”ovitim crnogoriÄnim sastojinama, zabilježena najveÄa razlika meÄu ekoloÅ”kim skupinama ptica izmeÄu dva Parka. Strukturalne razlike tih Å”uma izmeÄu dva Parka su rezultat razliÄite starosti sastojina, a ptice su imale veÄe gustoÄe u starijim Å”u-mama. MeÄu strukturalnim svojstvima vegetacije, ona vezana uz starost Å”ume (prosjeÄna temeljnica i broj mladih stabala) bile su znaÄajno korelirane s ukupnom gustoÄom populacija pjevica i s gustoÄom razliÄitih ekoloÅ”kih skupina. ZakljuÄak je ovog istraživanja da floristiÄki sastav Å”uma ima utjecaj na odabir tipa Å”ume u kojoj Äe se neke vrste ptica pjevica gnijezditi, dok na odabir samog podruÄja gniježÄenja veÄi utjecaj imaju strukturalna svojstva Å”ume
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