Bugs ‘n’ brates need sav­ing too


Creepy crawlies and all those other lit­tle guys may be creepy and crawly, but com­prise a truly in­te­gral por­tion of an ecosys­tem... So, let’s talk about New Zealand’s stream in­ver­te­brates.

We have all heard of the un­der threat whio and wry­bill, but have you ever thought about what they eat? Of­ten when we speak of con­ser­va­tion, we look at cud­dlier crea­tures to which the public re­lates. Do not mis­un­der­stand, these birds are im­por­tant to the ecosys­tem; how­ever, we do tend to over­look the tinier species that are re­quired for any suc­cess­ful ecosys­tem to per­pet­u­ate.

Most of us could list sev­eral species, unique to New Zealand, that are en­dan­gered, but I bet that not many of us could list many (if any) in­sects, crus­taceans, snails or worms that are equally at risk as our wa­ter ways be­come less pris­tine.

For­est & Bird Manawatu is cur­rently host­ing a se­ries of monthly lec­tures on fresh­wa­ter con­ser­va­tion. The first talk in Septem­ber had An­drew Watt from Hori­zons speak­ing on ‘Fresh­wa­ter pests – their im­pact and con­trol’ and how dif­fer­ent in­tro­duced al­gae species are im­pact­ing on our fresh­wa­ter ecosys­tems. The ul­ti­mate im­pact of course is on our na­tive birds and fish.

The spread of weeds (e.g. didymo and horn­wort) into our fresh­wa­ter streams and rivers is dis­plac­ing in­ver­te­brates from their nat­u­ral habi­tats, leav­ing fish and birds with­out their food source.

Fresh­wa­ter in­ver­te­brates are be­com­ing well recog­nised as in­di­ca­tor species in de­ter­min­ing the health of our wa­ter­ways.

The com­po­si­tion of this minute com­mu­nity is shaped by a com­bi­na­tion of phys­i­cal habi­tat and wa­ter qual­ity fac­tors. Sev­eral stud­ies have shown that the amount of fish at a par­tic­u­lar site is sig­nif­i­cantly af­fected by in­ver­te­brate biomass, or pop­u­la­tion size. There are many pro­grammes ask­ing the com­mu­nity to pitch in and help iden­tify and mon­i­tor in­ver­te­brates in lakes, rivers, and streams, so that we can learn more about our wa­ter­courses.

For an in­side ac­count of the in­te­gral part in­ver­te­brates play in our en­vi­ron­ment, all are welcome to hear Dr. Rus­sell Death, Pro­fes­sor in Fresh­wa­ter Ecol­ogy, Massey Univer­sity, speak to For­est & Bird next Tues­day evening Oc­to­ber 13 from 7.30pm, in City Li­brary on Ge­orge St.


Ne­samele­tus – swimming mayfly nymph. An abun­dance of Ne­samele­tus sug­gests good habi­tat and wa­ter qual­ity con­di­tions, es­pe­cially if other mayfly or stone­fly groups are also abun­dant.

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