The per­ils (or ben­e­fits) of flood­ing for wildlife

Macclesfield Express - - THE LAUGHING BADGER - SEAN WOOD

THE re­cent down­pours set so­cial me­dia alight, as peo­ple com­plained about ex­tended jour­neys home, flooded streets and flat­tened gar­dens, but spare a thought for the wildlife, be­cause sud­den spates as we ex­pe­ri­enced can be dev­as­tat­ing.

For ex­am­ple, many hedge­hogs will have drowned in their sleep while set­tling into hi­ber­na­tion. Of course, there is noth­ing we, or in­deed they, can do about it, and it got me think­ing about how the flash floods could have af­fected other an­i­mals.

Barn owls: Night af­ter night of wet weather means barn owls can’t get out to hunt with­out their del­i­cate (and silent) plumage be­com­ing wa­ter­logged.

Wa­ter voles and ot­ters: Wa­ter voles spend much of the win­ter in their bur­rows where they store food. But wa­ter lev­els can rise so fast that voles are flooded out of bur­rows and washed away. De­spite their name, they are not strong swim­mers so may try and take refuge on higher ground, where un­for­tu­nately they are easy prey for preda­tors such as Amer­i­can mink and birds of prey. Ot­ter holts may also be flooded in such con­di­tions.

Foxes, badgers and hares: Gen­er­ally speak­ing these an­i­mals can es­cape if their dens, sets or their fields are flooded but there are times when they get caught out and have to swim for it.

Fish-eat­ing birds: The deep, fast-flow­ing rivers and streams that are also cloudy due to the sed­i­ment loads make hunt­ing dif­fi­cult for birds such as herons and king­fish­ers.

Snipe and other wad­ing birds: Although they like damp mead­ows, flood­ing can se­verely hin­der their feed­ing.

Fish: The eggs of mi­gra­tory fish such as At­lantic sal­mon and brown trout that have been laid in grav­els on the river bed are at risk of being washed away.

The way land and rivers are now man­aged causes prob­lems for wildlife. The fact that many of our species and habi­tats are frag­mented is a ma­jor prob­lem dur­ing these ex­treme events. In a large area of wet­land, there is usu­ally some­where for species like wa­ter voles to take refuge that is still fairly safe. If the wet­land is just a lin­ear strip of habi­tat along­side the river, there is nowhere for voles to go. Where big em­bank­ments line rivers (to al­low farm­land to be drained as part of his­toric flood de­fences), flood­wa­ter that over-tops the banks gets trapped for long pe­ri­ods of time.

This ly­ing wa­ter can drown all the worms and in­sects that live in the soil which are vi­tal food for birds like waders (and the farm­ers can lose their grass). The land drainage em­bank­ments which al­low land to be farmed more in­ten­sively also push wa­ter down­stream in­creas­ing the risk of flood­ing to com­mu­ni­ties down­stream.

Deeper, wider ditches that are ex­ca­vated in an at­tempt to re­duce flood­ing will re­sult in lower ground wa­ter lev­els through­out the rest of the year, which may af­fect a wide range of plant com­mu­ni­ties and the species that de­pend on them

Heavy rain­fall causes storm sew­ers to open, re­leas­ing pol­lu­tion - un­treated waste and toxic sub­stances that peo­ple pour down drains. When this ends up in our rivers it has dis­as­trous con­se­quences for wildlife. In­ten­sive agri­cul­ture causes high lev­els of silt build-up caus­ing poor wa­ter qual­ity.

In gen­eral, how­ever, flood­ing is a nat­u­ral process and when it is not ex­ces­sive, can ben­e­fit many species.

Flood­wa­ters help plants and an­i­mals to dis­perse across the land­scape. Seeds are moved around in flood­wa­ters, set­tling in new places and al­low­ing plants to colonise new ar­eas. Un­for­tu­nately this also means that prob­lem (in­va­sive) plants like Gi­ant Hog­weed or Hi­malayan Bal­sam spread down­stream in such flood events.

Some of the rare wa­ter snails need flood­ing to move from one lo­ca­tion to an­other. Anisus vor­tic­u­lus - the lit­tle ramshorn whirlpool snail is a rare species that of­ten oc­curs in ditches in wet fields that flood in win­ter, flood­ing is thought to be im­por­tant in en­abling young snails to colonise new ditches.

The smaller tem­po­rary ponds that are cre­ated dur­ing flood­ing pro­vide breed­ing sites for the com­mon frog. Flooded ar­eas en­able ducks such as pochard, tufted duck and teal to feed in new ar­eas of open wa­ter.

On a lighter note, there were un­usual scenes at the RSPB’s Old Moor Re­serve in the North of Eng­land af­ter a re­cent down­pour. The war­den, who was stranded on his own in the Vis­i­tor Cen­tre, the only bit of the re­serve above the wa­ter, was soon joined by all man­ner of mam­mal refugees, in­clud­ing, squir­rels, rab­bits, voles, moles, hares, mice and shrews... oh, and rats.

A snipe feed­ing in flooded fields

The Laugh­ing Badger Gallery, 99 Platt Street, Pad­field, Glos­sop

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