Chruściki (Trichoptera) jezior Polski

Po obronie pracy magisterskiej (chruściki rzeki Pasłęki - badania trzyletnie) chciałem kontynuować tematykę rozmieszczenia siedliskowego chruścików w rzekach pojezierza, z myślą o pracy doktorskiej. Promotor zdecydował jednak inaczej i skierował mnie na jeziora. Ale nie ma tego złego, co na dobre by obrócić nie było można :). W tym czasie dysponowałem już materiałem z Jeziora Wulpińskiego oraz Skanda.

Do zasadniczych badań wybrałem jeziora, które poznałem... w czasie wakacyjnej wyprawy w okresie liceum: jeziora Narckie, Warchałdzkie i Brajnickie. Dołączyłem także jezioro Skadna  w Olsztynie. Rozpoczął się okres systematycznych wyjazdów terenowych i poszukiwania publikacji. Okazało sie że problematyka siedliskowego rozmieszczenia larw chruścików w jeziorach jest słabo poznana.

Po obronie pracy doktorskiej tematykę chruścików jeziornych kontynuowałem (obok innych watków hydrobiologicznych i chruścikarskich). Dotarłem  do dr Wandy Szczepańskiej z Mikołajek (Stacja Hydrobiologiczna Instytutu Ekologii PAN), która przekazała mi swoje bogate zbiory i notatki z badań na jeziorach mazurskich z lat 60. i 70. XX w. Korzystałem także z rozmaitych możliwości uzupełniania matreiału z różnych części Polski a także z Obwodu Kaliningradzkiego i Białorusi. Współpracowałem także z Instytutem Rybactwa Śródlądowego w Olsztynie, w badaniach Jeziora Żarnowieckiego. 

Tak powstała monografia o chruścikach jezior Polski, ale z wieloma uniwersyalnymi i ponadregionalnymi wnioskami.

Badania terenowe, Jezioro Wygoda na Pomorzu. Przebieranie materiału.

Po habilitacji i wydaniu momnografii jeszcze dozbierało mi się zupełnie nowych danych, w tym bogaty materiał z jezior lobeliowych. Daje to pełniejszy i bardziej uniwersalny obraz siedliskowego i regionalnego rozmieszczenia chruścików w jeziorach a także zmiany wynikające z eutrofizacji oraz rekultywacji jezior.

Pojawil się także zupełnie nowy problem wynorzystania bentosu w biomonitorungu jezior. Powoli przymierzam się do podsumowania zebranych danych oraz pokuszenia się o opracowanie metody biondykacji dla jezior. Tradycyjne indeksy biotyczne w przypadku jezior się nie sprawdzają z różnych względów.

Jezioro Trzcinno k. Łężan, najnowsze okazjonalne chruścików jezior
- przy okazji oceny bioróżnorodności w uprawach wierzby energetycznej.

Wybrane publikacje, dotyczace chruscików jezior:

• Czachorowski S., 1989. Vertical distribution of Trichoptera in three Masurian lakes - results of initial research. Pol. Arch. Hydrobiol., 36, (3): 351 - 358. 
• Czachorowski S., 1993. Vertical distribution of caddis larvae in various types of lake littoral. Braueria 20: 7-9. 
• Czachorowski S., 1993. Distribution of Trichoptera larvae in vertical profile of lakes. Pol. Arch. Hydrobiol., 40: 139-163 
• Czachorowski S., R. Kornijów. 1993. Analysis of the distribution of caddis larvae (Trichoptera) in the elodeid zone of two lakes of East Poland, based on the concept of habitatual islands. Pol. Arch. Hydrobiol., 40: 165-180. 
• Czachorowski S., 1994. Habitat distribution of caddis larvae in the north-eastern Polish lakes. Braueria, 21: 15-16. 
• Czachorowski S., 1994. Chruściki jezior lobeliowych - wyniki wstępnych badań. W: M. Kraska (ed.) Jeziora lobeliowe, charakterystyka, funkcjonowanie i ochrona, cz. II. Idee Ekologiczne, t. 7, ser. Szkice, nr 5: 59-73. 

• Czachorowski S., 1994. Larwy chruścików (Trichoptera) z jezior Pojezierza Pomorskiego. Przeg. Przyr., 5 (1): 35-42. 
• Czachorowski S., 1994. Concomitance of caddis fly (Trichoptera) larvae in four Masurian lakes differing trophically (north-eastern Poland). Acta Hydrobiol., 36: 213-225. 
• Czachorowski S., 1995. Larwy chruścików (Trichoptera) czterech jezior różniących się trofią (północna Polska). Przeg. przyr., 6: 21-52. 
• Czachorowski S., A. Kurzątkowska, 1995. Chruściki (Trichoptera) i pluskwiaki (Heteroptera) wodne zanikającego zbiornika koło Żabiego Rogu (Pojezierze Mazurskie). Przeg. Przyr., 6: 53-60. 
• Czachorowski S., 1996. Caddis flies (Trichoptera) of the Zehlau Peatbog - results of preliminary studies. Kaliningrad, Flora i fauna bolota Celau, tezisy dokladov mezdunarodnoj naucnoj konferencji, str. 49-51. 

• Czachorowski S., 1997. Skąd się wzięły chruściki (Trichoptera) w jeziorach Polski - analiza strategii życiowych. W: T. Puszkar i L. Puszkar (red.) Współczesne kierunki ekologii - ekologia behawioralna, Wyd. UMCS, Lublin, str.: 175-178. 
• Czachorowski S. 1998. Chruściki (Trichoptera) jezior Polski - charakterystyka rozmieszczenia larw. Wyd. WSP Olsztyn, 156 str. 
• Czachorowski S., 2003. Caddisflies (Trichoptera) of Polish lakes – ask about origin lake species and post-glacial colonization. In: Lake ecosystems: biological processes, anthropogenic transformation, water quality. Materials of the II Inter. Sci. Conf., Minsk: 543-545. 
• Pietrzak L., S. Czachorowski, 2004. Jak rekultywacja wpływa na owady wodne? Przykład chruścików (Trichoptera) z Jeziora Długiego w Olsztynie. W: Wiśniewski R., Jankowski J. (red.) Ochrona i rekultywacja jezior. Pol. Zrzesz. Inż. i Tech. Sanitarnych, Oddz. Toruń, str.: 187-194. 
• Czachorowski S., Pietrzak L., Zawal A., 2007. Chruściki (Trichoptera) rezerwatu „Jezioro Szare” i jego otuliny. Parki nar. i Rez. Przyr., 26 (4): 105-114. 
• Szymańska U., Czachorowski S., Markiewicz A., Bonar A., Zębek E., 2010. Chruściki (Trichoptera jako organizmy wskaźnikowe zabiegów rekultywacyjnych prowadzonych na jeziorze Jeziorak Mały (Caddisflies Trichoptera as indicator organizm of restoration works carried out in the Lake Jeziorak Mały. W: R. Wiśniewski (red.) Ochrona i rekultywacja jezior. Toruń, str.: 127-140. 
• Czachorowski S., 2010. Caddisflies (Trichoptera) of Lobelian Lakes of the Pełcznica Nature Reserve (Pomeranian Lakeland, Poland). Acta Biologica nr 17: 59-71.

Gdzieś na Pomorzu.

Cadisflies (Trichoptera) of Polish lakes - ask about origin lake species and post-glacial colonization

Caddisflies (Insecta: Trichoptera) are one of the most important aquatic groups that inhabit a lake littoral. The ecological significance of Trichoptera in lakes results from the large quantity of larvae, their relatively large partition in the littoral macrobenthos biomass and their presence among most functional feeding groups.

It will be presented the results if multi-year research into caddis-flies inhabiting Polish lakes, including the  species composition and the structure of habitat distribution. It is also an attempt to answer the following questions: what are the species occur in Polish lakes, what is the grade of specify of lake fauna  and there any differences in larvae distribution in lakes differing in regional location, in trophy type and catchment’s basin? The question of fauna origin, including the regions, environmental and life-history styles was brought up. The author also tried to formulate the general patterns of caddis larvae distribution in lakes. This work is the first to provide relatively full characteristics of larvae distribution in Polish lakes and the first such work on European lakes. Due to the fact that littoral distribution of other invertebrates have not been described well, this work opens the discussion on macrobenthos distribution in lakes.

The research material comprises close to 70 thousands caddis larvae and adults, collected between 1951 and 1997 from around 200 lakes located across Poland. Main results were published [Czachorowski 1998]. Now, it will be compared with some data on caddislies from Belarussian lakes and lowland rivers.

The analysis of the available data showed that 60% of the species (154 species) of the national caddisfly fauna is co-related to lakes. The author suggests distinguishing three ecological groups as follows: limnepbionts (lake species, exclusively or mainly occurring in lakes), limnephilous (often and numerously occurring in lakes) and limnexens (accidentally occurring in lakes) bearing in mind that division lines between them are not sharp. Among the 49 limnepbionts, almost all species occur widely in regions located in lowlands. Most of the limnebionts inhabit the elodaids (32 species), a large number of them inhabit helophytes (25) and few of them inhabit the shallowest littoral. Among the 39 limnephilous, as many as 31 occur widely and a few of them occur in narrow areas and mountains. The largest quantity of limnephilous are connected with the potamal zone (25 species), less with rhitral (7), small water bodies (4) or with peat-bog waters (2). Limnephilous inhabit mainly the shallowest, not overgrown littoral (10 species) and the helophytes (15), more seldom elodeis (5). In the group of limnexens (66 species) only around half of the species occurred widely and 8 species occurred in narrower ranges and in mountains. Seven of the limnexens are connected with springs (crenal), 20 of them with steams (rhitral zone), 23 with rivers (potamal zone), 10 of the with small water bodies and 6 with marsh waters. Clearly most of the species are connected with the shallowest, not overgrown littoral (30 species), less with the helophytes (15) and only 4 with elodeids. 22 species were also distinguished in relation to dystrophic and marsh waters (tyrphobionts and tyrphilous).

Analyzed caddisfly fauna can be described as relatively eurytopic and widely-occurring with numerous species of northern distribution. The most specific fauna inhabits dipper littoral of lakes (elodeids zone) and to a lesser extent the helophytes. The largest quantity of accidental species is present in the shallowest, not overgrown littoral (mainly in mountain lakes with low trophy).

Three levels of differentiation could be distinguished in the larvae distribution characteristics: geographic (regional), landscape (lake type and influence of the surrounding) and habitatual (habitats in lakes). The levels illustrate the three dispersion aspects. The geographical differentiation may result from climatic and historic differences (post-glacial species dispersion). The landscape differentiation may have been caused by the influence of fauna migration from the other water habitats neighbouring with lakes (e.g. from rivers, peat-bogs, fens, canals) and it could be also interpreted as adaptation to life in a changing landscape, or possibility as living in water habitats of different types which neighbour with each other in the Lakeland landscape and in a valley of big lowland rivers (lakes, rivers, temporary pools etc.).

Based on collected information, several synecological groups were distinguished which differed  in biological adjustment to life in lake, in habitat distribution and in the origin (the different species of the shallowest not overgrown littoral, the species of the helophyte zone and the species of the elodeid zone). Several smaller groups were also distinguished which lie along the trophy gradient and the stability of lake habitats. The differences in the average size of larvae between the dipper and shallowest littoral, phonological differences in life cycles and taking up seasonal migration by larvae of some species are interpreted also as adjustment to pupation on water surface or overwater parts of plants and as adaptation to avoiding predators.

The influence of the lake trophy is expressed by the vertical distribution of caddis larvae and in the contents of typical species for the elodeid zone. Differences in the dominance and quantity of larvae of some species were also observed. In lakes with lower trophy, the winter quantity reduction of caddis larvae in the elodeid zone was observed clearly smaller than in lakes with higher trophy. During eutrophication, species characteristic for the elodeids and rheophilous species inhabiting rocky and sandy bottom in the shallowest littoral are eliminated first. Clear changes in species quantity in the zone of the helophytes are only visible in extremely euthrophicated lakes.

The present caddisfly fauna of Polish and Belorussian lakes is relatively young and could be described as post-glacial. It mainly consists of species with wide range of distribution and with wide habitat preferences. The species existing in the Polish and Belorussian lakes to a large extent originate from small waters habitats (fens, forest pools). This is mainly true for species of the helophyte zone. A part of them apparently originates from potamal (mainly the species of the elodeids), other from the rhitral zone (mainly the species of the not overgrown littoral). The northern origin of some species has its expression in their adjustment to life in shallow lake zone and small water-bodies.

Trichoptera inhabiting the lakes recruits from taxons formed in the Tertiary, however from the origin point of view they are species such as mountain, boreal and arboreal. The oreal species were formed in mountains and their existence in lakes is accidental. It is surely an old group adjusted to flowing waters, existing only in oligotrophic or mesotrophic lakes (especially coldwater) with, in turn, may be connected with a large amount of oxygen. From  the habitat point of view, these species are related mainly the rhitral zone. The boreal species were formed in the North Palearctic. They species adapted to life in low temperatures, in temporary pools, peat-bogs and in the helophyte zone. Some of them are small water-body limnexens. Considering their habitats, these boreal species are tightly connected with temporary waters and marshes. The arboreal species, however, are connected with the zone of deciduous forests. In this group of caddiflies clear adaptation to detritus and autumn leaf fall consumption could be observed. Limnebionts consist the largest part of the arboreal species group. They are mainly connected with the potamal and permanent still waters, to a lesser extent with small forest pools and marshes. The arboreal species have a wide geographical distribution.

The author describes the changes in caddisfly fauna during lake succession both in harmonic and disharmonic sequence with the attention to two main succession mechanisms such as ability to colonize free habitats and the ability to survive in conditions of strong competition. Faunal changes during lake succession were also compared to the fauna changes in the longitudinal river zoning with attention to the similarities in trophy changes, habitat differentiation and environmental stability. Relatively large number of limnephilous and limnexens shows the lack of clearly adaptations to life in lake habitats which may be the result to relative young age of lakes.

It could be expected that the eurytop (opportunistic) character of species and wide distribution extent are caddisflies adjustments to life in changing post-glacial landscape (formation and disappearance of lakes) and the landscape of river ravine on lowlands where there are flowing waters, still water reservoirs (old river-beds among them) and temporary flooding valleys exist in parallel. Boreal and arboreal species have possibility to coexistence in valleys of large lowland rivers.