OT­TERS RE­TURN TO THE DON

Yorkshire Post - - FEATURES & COMMENT -

IT IS a blink-and-you’ll-miss-it mo­ment. How­ever, while the first ever on-screen ap­pear­ance of an ot­ter in the Peak District might last just a few sec­onds, its en­vi­ron­men­tal sig­nif­i­cance could be much more long last­ing.

The footage, show­ing an ot­ter mark­ing its ter­ri­tory on the banks of a river, was filmed by Dr Dou­glas Ross, a vol­un­teer on a project be­ing led by the Univer­sity of Sh­effield, which is help­ing to chart the slow but steady resur­gence of the crea­tures once on the verge of ex­tinc­tion in the UK.

“It’s amaz­ing to watch,” says Dr Deb­o­rah Daw­son, who is based at the univer­sity’s depart­ment of an­i­mal and plant sciences. “Ot­ters are noc­tur­nal crea­tures. Even in ar­eas where we know they ex­ist they are in­cred­i­bly dif­fi­cult to spot, so the fact that this is the first one caught on cam­era in the Peak District is some­thing re­ally special.”

Ot­ter num­bers crashed in the UK from the mid-1950s on­wards, with the in­tro­duc­tion of pow­er­ful agri­cul­tural pes­ti­cides partly blamed for their dec­i­ma­tion. By the 1970s, as residues from these chem­i­cals be­gan to build up in wa­ter­ways, ot­ters had all but dis­ap­peared from large parts of the coun­try. The North of Eng­land was par­tic­u­larly badly hit and many feared that the an­i­mals were gone for­ever.

“Fifty years ago, the River Don was one of the most pol­luted rivers in Europe and as a re­sult it wiped out the pop­u­la­tion of ot­ters which had been liv­ing in the re­gion,” says Dr Daw­son. “It wasn’t alone. Over a rel­a­tively short pe­riod, Bri­tain’s’ wa­ter­ways had re­ally taken a hit and by the time peo­ple started to an­a­lyse what was go­ing on much of the nat­u­ral habit was al­ready in crit­i­cal con­di­tion.”

The first na­tional ot­ter sur­vey, which was car­ried out be­tween 1977 and 1979, con­firmed the worst. Of the 2,940 sites looked at, just five per cent were still home to ot­ters and the news sparked a ma­jor con­ser­va­tion ef­fort.

“There isn’t one sin­gle rea­son why ot­ter num­bers have in­creased, rather it is a com­bi­na­tion of cir­cum­stances,” says Dr Daw­son. “Bans on var­i­ous pes­ti­cides were in­tro­duced, there has been in­creased le­gal pro­tec­tion, more gen­eral im­prove­ments in wa­ter qual­ity as well as tar­geted con­ser­va­tion ef­forts.

“To­gether these have all cre­ated an en­vi­ron­ment where ot­ters can thrive. How­ever, even with all those mea­sures, re­cov­ery has still been slow in the North of Eng­land. We are not en­tirely sure why, but our aim now is to work out what we can do to en­cour­age more of them to come back.”

Ear­lier this year, signs of ot­ter life were de­tected in South York­shire when re­searchers con­ducted the first ever DNA sur­vey of num­bers in the North of Eng­land.

Work­ing in col­lab­o­ra­tion with the Univer­sity of Leeds and the Sh­effield and Rother­ham Wildlife Trusts, Dr Daw­son and her team be­gan analysing ot­ter drop­pings, known as spraint, which re­vealed that a small pop­u­la­tion had re­turned to the Sh­effield stretch of the river for the first time in al­most half a cen­tury.

“We were able to de­tect seven ot­ters, in­clud­ing at least two males,” she says. “In­ter­est­ingly our re­search also showed that ot­ters were pop­ping up in ur­ban, subur­ban and ru­ral lo­ca­tions across the whole of the South York­shire re­gion with one fe­male de­tected in quite re­mote area north of the city.

“Fe­males can travel up to six miles, males up to 24 miles and pre­vi­ous stud­ies have sug­gested that ot­ters can have very large ter­ri­to­ries that do not over­lap. While it is there­fore un­likely that more than one adult male or one mother with cubs is res­i­dent in Sh­effield, if we are go­ing to sup­port the ot­ter pop­u­la­tion to grow then we have to make sure the pas­sage through the city and along the River Don re­mains as clear as pos­si­ble.

“If that is to hap­pen, we have to hope that many of the cur­rent and planned river­side de­vel­op­ments can be done sym­pa­thet­i­cally to al­low the cur­rent wildlife pop­u­la­tions to thrive.”

The ot­ter come­back is one of English na­ture’s real suc­cess sto­ries. Be­tween 2000 and 2002 when the fourth ot­ter sur­vey was car­ried out, more than 36 per cent of the orig­i­nal sites re­vealed traces of the an­i­mal. Six years ago when ot­ters were found it Kent, the an­i­mal had a pres­ence in all coun­ties in Eng­land once again.

Much of the in­crease has been down to nat­u­ral re­cov­ery, but in the early 1980s Nat­u­ral Eng­land, work­ing with the Ot­ter Trust, also de­vel­oped a rein­tro­duc­tion pro­gramme to re­pop­u­late parts of East­ern Eng­land with cap­tive-bred ot­ters.

Be­tween 1983 to 1999, 117 cap­tive­bred ot­ters were re­leased mostly on East Anglian rivers and a sep­a­rate pro­gramme saw 59 wild ot­ters, which had been re­ha­bil­i­tated af­ter be­ing or­phaned or in­jured, given a new home in York­shire.

By the early 1990s it was de­cided that rein­tro­duc­tions were no longer nec­es­sary. How­ever, the var­i­ous ot­ter pop­u­la­tions still need mon­i­tor­ing to en­sure their long-term health and now Dr Daw­son is look­ing to se­cure fund­ing to con­tinue the DNA project.

“We were for­tu­nate that we had a vis­it­ing MSc stu­dent to help with the ini­tial anal­y­sis and now we are look­ing for a fur­ther £2,500 so we can re­ally make the most of this project,” she says. “To be able to use ge­netic anal­y­sis to in­ves­ti­gate ot­ters on the River Don and learn more about this very elu­sive mam­mal has been our amaz­ing ex­pe­ri­ence. Our re­sults match well with pre­vi­ous records of ot­ter pres­ence which had been based on sight­ings around Sh­effield, but we were able to take this fur­ther to pro­duce the first DNA-based es­ti­mate of ot­ter num­bers in the re­gions.”

Once com­plete, it is hoped the project will help pin­point likely bar­ri­ers pre­vent­ing the ot­ters mov­ing into dif­fer­ent ar­eas and pro­vide con­ser­va­tion groups with a blueprint to map other pop­u­la­tions in dif­fer­ent parts of the coun­try.

While the orig­i­nal threats of pol­lu­tion may be no more, the fu­ture of the ot­ter is not en­tirely as­sured with se­vere flood­ing, in­creased road traf­fic and habi­tat loss all hav­ing been iden­ti­fied as caus­ing po­ten­tial harm to ex­ist­ing pop­u­la­tions.

“The fact they are in the River Don demon­strates that there must have been sig­nif­i­cant im­prove­ments to the wa­ter qual­ity, but through the DNA anal­y­sis we can also iden­tify what their diet con­sists of. Once we know what other species are present then that will give us an even more de­tailed pic­ture of the health of the river.”

Dr Ross said: “See­ing this footage and know­ing the ot­ters are mov­ing around the Peak District is re­ally ex­cit­ing and the po­ten­tial to use spraint DNA to iden­tity the spe­cific in­di­vid­ual and its diet makes it all the more per­sonal.”

Dr Daw­son is keen to find out more about Sh­effield’s ot­ter dis­tri­bu­tion in the Peak District. Any­one in­ter­ested in the project, in­clud­ing po­ten­tial spon­sors, can email d.a.daw­son@ sh­effield.ac.uk

To watch the ot­ter footage go to york­shire­post.co.uk

Ot­ters were on the brink of ex­tinc­tion, but have made a re­mark­able come­back.

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