Prostorsko-časovne premene habitatov obmorskih mokrišč kot posledica primarne sukcesije in dvigovanja morske gladine

doktorska disertacija

Danijel Ivajnšič (Author), Mitja Kaligarič (Mentor), Lovrenc Lipej (Thesis defence commission member), Lučka Kajfež-Bogataj (Thesis defence commission member)

Abstract

Razumevanje vzrokov za prostorsko razporeditev rastlin je eden od glavnih ciljev ekologije. Prav slednje je zelo pomembno, kadar želimo ustvariti novo podlago za razvoj vegetacije v naravovarstvene namene. V primeru Škocjanskega zatoka so bili novi poloji pazljivo načrtovani in ustvarjeni v različnih oblikah na različni mikro-nadmorski višini z namenom doseči spontani razvoj vsaj dveh ali treh ciljnih habitatnih tipov (muljasti in peščeni poloji brez vegetacije, halofitne enoletnice in halofitne trajnice z vsemi vmesnimi oblikami) ob upoštevanju procesa sukcesije. Na ta način je študija v Škocjanskem zatoku po eni strani predstavljala poseben prostorski eksperiment (spremljanje primarne sukcesije na novo ustvarjenih polojih) in po drugi strani praktičen naravovarstveni ukrep za renaturacijo degradiranega območja. Ta uspešno načrtovan, izveden in opazovan "ekološki eksperiment" v vrednosti 0.45 milijonov evrov lahko v splošnem velja za primer dobre prakse pri renaturaciji halofitnih rastlinskih združb oziroma prednostnih habitatov EU na sedimentnih obalah v obmorskih mokriščih širom Evrope. Pomembnost takšnih študij se znatno poveča ob upoštevanju vse resnejše grožnje, s podnebnimi spremembami pospešenega, dvigovanja morske gladine in vse večjega antropogenega pritiska na obalne predele - posledica tega je proces, ki ga v angleščini imenujemo "coastal squeeze". Zaradi omenjenih groženj in pritiskov je halofitna vegetacija sedimentnih obal že sedaj pretežno omejena na obstoječa zavarovana območja, ki pa so obdana s številnimi cestami, z nasipi, s kanali, z intenzivnimi kmetijskimi površinami in urbanimi območji. Na ta način nadomestitev kopenske migracije ciljnih halofitnih habitatov evropskih obal s prihrankom območij, ki so brez fizičnih barier in omogočajo premik teh ekosistemov, ni preprosta. Študija v Škocjanskem zatoku je tako dokaz, da s pazljivo pripravo umetnih površin na ustrezni mikro-nadmorski višini, pod rednim vplivom plimovanja, dosežemo postopni razvoj ciljnih ogroženih habitatov po pretežno deterministični sukcesijski poti. Hkrati je model premene habitatov, ki temelji na mikro-nadmorski višini, pokazal bistvene spremembe v prihodnji prostorski razporeditvi obalnih habitatov v Škocjanskem zatoku in Sečoveljskih solinah zaradi dvigovanja morske gladine. Predviden je postopni umik muljastih in peščenih polojev ter halofitnih enoletnic ob upoštevanju ali lokalnega trenda ali globalnih modelnih napovedi dvigovanja morske gladine (IPCC AR4). Do srede 21. stoletja se lahko drastično zmanjša površina halofitnih trajnic. Po scenariju A1FI (tehnologija fosilnih goriv) bi le-te lahko v Škocjanskem zatoku do leta 2100 celo popolnoma izginile. Modelne napovedi tako kažejo 42-odstotno zmanjšanje vseh Natura 2000 habitatov do leta 2060 na obeh območjih raziskave. Posledično v študiji predlagamo tri protiukrepe za ohranjanje ciljnih habitatnih tipov. Najbolj ''naravni'' omilitveni ukrep je premik obalnih habitatov z uporabo varovalnih pasov (1), kjer so le-ti na voljo. Druga rešitev, izvedljiva v obeh zavarovanih območij, je gradnja umetnih otočkov z uporabo lokalnega izkopanega materiala (2). V Sečoveljskih solinah bi 22 otočkov in okopnitvena cona na ustreznih legah, primernih za habitate, katerim model napoveduje zmanjšanje površine, lahko nudilo dodatnih 10 ha za halofitno vegetacijo. 21 otočkov in 2 polotoka (skupaj 13 ha) na dveh različnih mikro-višinah bi lahko zagotovilo preživetje trem različnim habitatom v Škocjanskem zatoku. Na območju Sečoveljskih solin bi lahko z umetno regulacijo morja v opuščenem predelu na način, podoben polderjem, pridobili ustrezno površino za ciljne Natura 2000 habitate (3). Z uporabo naštetih protiukrepov bi ohranili 32 ha zavarovanih habitatov. Sklepamo lahko, da je ustrezne strateške načrte v obalnih mokriščih, ki lahko vsebujejo naštete protiokrepe, potrebno pripraviti pazljivo in predvsem pravočasno.

Keywords

dvig morske gladine;halofiti;obalna mokrišča;klimatske spremembe;potencialne gnezditvene površine;sukcesija;Sečoveljske soline;Škocjanski zatok;disertacije;Rastlinstvo;Ekologija rastlin;Vegetacijski pasovi;Morska obala;Halofiti;Habitati;Morska gladina;Slovenija;

Data

Language:	Slovenian
Year of publishing:	2015
Typology:	2.08 - Doctoral Dissertation
Organization:	UM FNM - Faculty of Natural Sciences and Mathematics
Publisher:	D. Ivajnšič]
UDC:	574.2:581.524(252.6)(497.472)(043.3)
COBISS:	279981568
Views:	1330
Downloads:	198
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Spatio-temporal shifts of coastal wetland habitats driven by primary successon and sea level rise
Secondary abstract:	One of the main aims of plant ecology is to understand the causes for patterns in plant distribution. This is especially important when we want to create new grounds for vegetation development for conservational purposes. It was carefully planned that new mudflats were created (in different shapes) on a gradient of different microaltitudes, aiming to achieve the spontaneous development of at least three target habitat types (mudflats, halophyte annuals and perennials, including the transitional forms between them) through the primary succession pathways. Thus, the study in Škocjan Inlet Nature Reserve was actually projected as a field experiment on one side and a practical conservation measure, to recover degraded area, on another side. This successfully planned, carried out and monitored "ecological experiment" worth 0,45 million Euros might have concrete implications on restoration or re-creation of halophyte plant communities on sedimentary seacoasts, all priority habitats of European Union, in general. This is especially important from the angle of climate change-driven sea level rise, which will certainly cause the s.c. "coastal squeeze" phenomenon. Owing to all the threats and pressures to coastal habitats and halophyte vegetation of sedimentary coasts in particular (beside sea level rise also anthropogenic impacts), the valuable areas are limited to the current protected areas, which are mainly bordered by roads, dykes, channels, intensive agriculture or urban areas. Thus, the landward migration of habitats on European coasts is not easy to accommodate simply by setting aside areas that are free of physical barriers for the retreat of these ecosystems. Our study proved that carefully planned ranges of microelevation gradient, with the pre-condition of a regular tidal regime, is leading to gradual development of target habitats following a deterministic successional pathway. Additionally, a habitat transition model, based on the correlation between individual habitats and micro-elevation intervals, showed substantial changes in the future spatial distributions of coastal habitats in Škocjan Inlet Nature Reserve and Sečovlje Salina Nature Park. Shifts between habitats will occur, but a general decline of 42 % for all Natura 2000 habitats is projected by 2060, according to local or global (IPCC AR4) sea level rise predictions. Three different countermeasures for the longterm conservation of targeted habitat types were proposed. The most "natural" is displacement of coastal habitats using buffer zones (1) were available. Another solution is construction of artificial islets, made of locally dredged material (2); a feasible solution in both protected areas. Twenty-two islets and a dried salt pan zone at the desired elevations suitable for those habitats that have been projected to decease in area would offer an additional 10 ha in the Sečovlje Salina. Twenty-one islets and two peninsulas at two different micro-altitudes would ensure the survival of 13 ha of three different habitats. In the area of Sečovlje Salina, abandoned salt pans could be terrestrialized by using permanent, artificial sea barriers, in a manner close to poldering (3). By using this countermeasure, another 32 ha of targeted habitat could be preserved. It can be concluded that, for each coastal area, where wetland habitats will shrink, strategic plans involving any of the three solutions should be prepared well in advance. The specific examples provided might facilitate adaptive management of coastal wetlands in general. Finally, climate change is expected to result in an acceleration in current rates of sea level rise, inundating many low-lying coastal and intertidal areas. This could have important implications for organisms that depend on these sites, including seashorebirds that rely on them for feeding habitat during their migrations, as a breeding ground or for overwintering.
Secondary keywords:	sea level rise;halophytes;coastal wetlands;climate change;potential nesting area;succession;Sečovlje Salina Nature Park;Škocjan Inlet Nature Reserve;dissetations;
URN:	URN:SI:UM:
Type (COBISS):	Doctoral dissertation
Thesis comment:	Univ. v Mariboru, Fak. za naravoslovje in matematiko, Oddelek za biologijo
Pages:	XII, 92 str.
ID:	8731439