NPPP 2022 SEA Scoping Report: Topic 4 Soils and Geodiversity

Cairngorms Nation­al Park Part­ner­ship Plan, SEA scop­ing Baseline inform­a­tion Top­ic 4 – Soils and geodiversity

Con­tents

Ques­tions for con­sulta­tion author­it­ies | 1 Con­text | 2 Land cap­ab­il­ity for agri­cul­ture | 2 Car­bon rich soils | 3 Con­tam­in­a­tion | 5 Soil erosion | 5 Geo­di­versity | 6 Pro­posed SEA object­ives | 9

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Ques­tions for con­sulta­tion authorities

1. Is there any­thing miss­ing from the Top­ic baseline?
2. Are there any errors in what is presented?
3. Are there any new ini­ti­at­ives, research pro­jects, plans, pro­grammes or strategies or oth­er things that will be report­ing / imple­men­ted over the next 12 – 18 months that are rel­ev­ant to the Top­ic, which may need to be included as the SEA progresses?

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Con­text

Soils cov­er much of the sur­face of the earth, form­ing the found­a­tion of all ter­restri­al eco­sys­tems and ser­vices. They sup­port key pro­cesses in bio­mass pro­duc­tion, atmo­spher­ic and hydro­lo­gic­al sys­tems. Nearly all of the food, fuel and fibres used by humans are pro­duced in soil. The func­tions provided by soil depend on a mul­ti­tude of soil organ­isms, which makes soil an import­ant part of our biod­iversity. Soil is second only to the oceans as a car­bon sink, with the poten­tial to play an import­ant role in the slow­ing of cli­mate change.

Although soils are a con­tinu­ally evolving, liv­ing and dynam­ic medi­um respond­ing to extern­al pres­sures and man­age­ment, their recov­ery from some dam­aging activ­it­ies such as devel­op­ment or pol­lu­tion may not take place with­in human times­cales. This means soils are a finite and essen­tially non-renew­able resource.

Land cap­ab­il­ity for agriculture

It is dif­fi­cult to value the dir­ect fin­an­cial con­tri­bu­tion that healthy soils make to our eco­nomy. How­ever it is now widely acknow­ledged that the sus­tain­able man­age­ment of soils, and the pro­tec­tion of the abil­ity of soil to deliv­er a wide range of envir­on­ment­al and eco­lo­gic­al ser­vices, is essen­tial to achiev­ing sus­tain­able eco­nom­ic growth.

Land Cap­ab­il­ity Clas­si­fic­a­tion for Agri­cul­ture map­ping provides detailed inform­a­tion on soil, cli­mate and topo­graphy for those involved in the man­age­ment of land use and resources. The clas­si­fic­a­tion ranks land from I to 7 on the basis of its poten­tial pro­ductiv­ity and crop­ping flex­ib­il­ity determ­ined by the extent to which its phys­ic­al char­ac­ter­ist­ics (soil, cli­mate and topo­graphy) impose restric­tions on its agri­cul­tur­al use. Land clas­si­fied from I to 3.1 is con­sidered to be prime agri­cul­tur­al land, while land clas­si­fied as 3.2 to 7 is con­sidered to be non-prime.

There are no areas of prime agri­cul­tur­al land with­in the Park, although there are areas of land in Strath Spey and Deeside with­in the 3.2 clas­si­fic­a­tion, around 1.2% of the total area of the Park (fig­ure 1). This indic­ates non-prime land that is lim­ited by mod­er­ate cli­mat­ic factors, which may yield a mod­er­ate range of crops with aver­age pro­duc­tion, but poten­tially high yields of bar­ley, oats and grass. How­ever the major­ity (around 73%) of land with­in the Park is clas­si­fied as 6 (rough graz­ing only) or 7 (very lim­ited agri­cul­tur­al value).

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Car­bon rich soils

Soil organ­ic mat­ter is plays a vital role in con­trib­ut­ing to a range of soil func­tions. Organ­ic car­bon is the dom­in­ant com­pon­ent of soil organ­ic mat­ter (around 50%), so man­age­ment of soil has import­ant wider con­sequences in the con­text of green­house gas emis­sions and cli­mate change. Soil organ­ic mat­ter also con­tains a wide range of nutri­ents such as nitro­gen and phos­phor­us, as well as trace ele­ments, all of which are essen­tial for plant growth and health.

Car­bon rich soils are import­ant car­bon sinks that if exposed, start to release car­bon back into the atmo­sphere. Car­bon diox­ide (CO2) release occurs via soil res­pir­a­tion or erosion caus­ing degrad­a­tion, but oth­er green­house gases can also be emit­ted as a res­ult of soil organ­ic mat­ter decom­pos­i­tion, for example meth­ane (CH4) and nitrous oxide (N2O). Although most CO2 is returned to soils as a con­sequence of the pho­to­syn­thet­ic activ­ity of plants, the dif­fer­ence between gains and losses of car­bon from land sur­faces may still be large. This is par­tic­u­larly the case for car­bon rich soils such as those cre­ated by peat­land hab­it­ats, which are very slow to regen­er­ate due to the cool wet con­di­tions stunt­ing plant growth. The soils of the Park are par­tic­u­larly rich in soil organ­ic mat­ter because the cool, moist cli­mate encour­ages the reten­tion of decom­posed organ­ic mater­i­als. Peat, the most car­bon rich soil, cov­ers an extens­ive area of the Park (fig­ure 2).

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Issues caused by cli­mate change may be com­poun­ded by unsus­tain­able land use activ­it­ies, peat extrac­tion and built devel­op­ment. Many of the most organ­ic rich soils of the Park are loc­ated on its moor­lands, large areas of which are man­aged for game. Deer can cause com­pac­tion and erosion by tramp­ling, so it is neces­sary to man­age the deer pop­u­la­tion towards a sus­tain­able level. Grouse shoot­ing requires man­age­ment of the moor­land hab­it­at such that a bal­ance of young heath­er is avail­able for grouse to for­age. This is nor­mally done by burn­ing (muir­burn), typ­ic­ally in patches that are burnt every 10 – 20 years. Poorly man­aged burn­ing can res­ult in dam­age to the under­ly­ing car­bon rich soils, res­ult­ing in green­house gas emissions.

Con­tam­in­a­tion

Soil con­tam­in­a­tion can come in many forms and sources. How­ever, not all are of con­cern with­in the Park. While small amounts of con­tam­in­a­tion from metals, organ­ic chem­ic­als, radio­act­ive sub­stances and patho­gens may occur with­in Park, due to the small scale of poten­tial sources, they are not of an order that is likely to cause sig­ni­fic­ant harm to the environment.

How­ever, because of its poten­tial effects on hab­it­at and biod­iversity, soil acid­i­fic­a­tion is of sig­ni­fic­ance. Typ­ic­ally, this pol­lu­tion ori­gin­ates from gaseous emis­sions of sul­phur diox­ide and oxides of nitro­gen that travel through the air before dis­solv­ing in rain to form sul­phur­ic and nitric acids that are sub­sequently depos­ited on soil, caus­ing soil acid­i­fic­a­tion. Excess depos­ition of nitro­gen can also lead to soil eutroph­ic­a­tion (although fer­til­iser applic­a­tion in excess of crop require­ments is more likely to be the cause of soil eutroph­ic­a­tion in lower lying soils used for agri­cul­tur­al and forestry).

Due to the absence of major indus­tri­al sources with­in or in close prox­im­ity to the Park, the main sources of aer­i­al acid­i­fic­a­tion are likely to be far out­with the Park, although emis­sions from traffic with­in the Park will con­trib­ute to a less­er extent (see Top­ic 2, Air).

Acid­i­fic­a­tion and eutroph­ic­a­tion impacts are often greatest in upland areas as a res­ult of high rain­fall. They are exacer­bated by pre­dom­in­antly poorly-buf­fered and nutri­ent-poor soils, with plants adap­ted to the loc­al nutri­ent poor con­di­tions being more sens­it­ive to changes in soil con­di­tions. How­ever, low­land soils, espe­cially those asso­ci­ated with eco­sys­tems of high con­ser­va­tion value, may also be affected by acid­i­fic­a­tion and eutroph­ic­a­tion. Acid­i­fic­a­tion can impact on soil nutri­ent cyc­ling, caus­ing crit­ic­al load exceedance and a reduc­tion in the abil­ity of soils to fil­ter con­tam­in­ants. Con­tam­in­ates may there­fore more read­ily enter water bodies.

Soil erosion

Soil erosion by water or wind is the pro­cess where soil particles become detached and are trans­por­ted with­in the land­scape. Fea­tures of soil erosion can be found through­out the Park. For example, land­slides and debris flows are a rel­at­ively com­mon occur­rence on many of the hill slopes shaped by ancient glaciers.

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As well as weath­er events caus­ing erosion, it can also be caused dir­ectly by human activ­ity, such as con­struc­tion, agri­cul­tur­al or forestry works, as well as indir­ectly through the effects of over­graz­ing caus­ing tramp­ling by live­stock and deer.

One of the most import­ant factors in the pro­tec­tion of soils from erosion is veget­a­tion cov­er, as roots bind soil particles togeth­er and plants pro­tect soil from dir­ect rain­drop impact, as well as dis­rupt­ing over­land flow. Where veget­a­tion cov­er is sparse, or soils are bare, the incid­ence of land­slides and soil erosion (by wind and water) is great­er. The rate of soil loss via erosion and the incid­ence of land­slides can be increased by remov­ing the veget­a­tion cov­er that pro­tects the soil such as plough­ing to grow crops or defor­est­a­tion, as well as through engin­eer­ing works.

In some upland areas of the Park, heavy graz­ing by sheep and deer has caused a decline in heath­er cov­er, which has then been replaced by tus­sock form­ing grasses with poorer soil bind­ing abil­it­ies. How­ever, there is dif­fi­culty in estab­lish­ing links between soil erosion (in par­tic­u­lar, the erosion of peat) and graz­ing as his­tor­ic stock­ing dens­it­ies, which are gen­er­ally unknown, may have had more influ­ence on the rate of erosion than cur­rent stock­ing densities.

Due to the pop­ular­ity of the Park as a vis­it­or and tour­ist des­tin­a­tion, the effects of recre­ation are also a factor in erosion in the Park. As well as increas­ing rates of erosion on exist­ing routes, recre­ation activ­ity can lead to the expan­sion of desire lines away from exist­ing routes. Where these go through sens­it­ive envir­on­ments, usu­ally upland areas where nat­ur­al regen­er­a­tion of the veget­a­tion is slow, the effects can be exaggerated.

Cli­mat­ic factors such as extreme rain­fall events play an import­ant part in the erosion pro­cess, by expos­ing soil and increas­ing run off that car­ries soil from the land into water­courses. Cli­mate change (see Top­ic I, cli­mat­ic factors) is there­fore likely to lead to an increase in the fre­quency of land­slides and in the intens­ity of soil erosion.

Geo­di­versity

Under­pin­ning, and in some instances, part of, soils is geo­di­versity. Many of the issues affect­ing soils also affect geo­di­versity, for example acid­i­fic­a­tion, erosion and unsym­path­et­ic land man­age­ment. Geo­di­versity is the vari­ety of rocks and soils laid down over mil­len­nia, which com­bine to cre­ate that land­forms that are the basis for landscapes.

Large scale Brit­ish Geo­lo­gic­al Soci­ety (BGS) map­ping is avail­able for Scot­land and there­fore the Park, how­ever detailed geo­mor­pho­lo­gic­al inform­a­tion is more lim­ited. SNH along with the BGS have com­piled a spa­tial invent­ory of the geo­mor­pho­logy of the Cairngorm Moun­tains core area (fig­ure 3). How­ever this offers only par­tial cov­er­age, mostly for the moun­tain­ous centre of the Park. As geo­di­versity is part of the spe­cial qual­it­ies of the Park, the par­tial cov­er­age is still a use­ful con­tri­bu­tion to the baseline.

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More detailed inform­a­tion is avail­able for Sites of Spe­cial Sci­entif­ic Interest (SSSI) and Geo­lo­gic­al Con­ser­va­tion Review (GCR) sites (fig­ure 4). These sites aim to safe­guard wider geo­di­versity with­in the Park.

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Pro­posed SEA objectives

SEA main object­ive	Sub-object­ives
4a: Min­im­ise con­tam­in­a­tion and safe­guard and improve soil, peat qual­ity and geodiversity	Will there be an effect on car­bon rich soils, in par­tic­u­lar peat?
	Will there be an effect on soil seal­ing, soil struc­ture and soil loss?
	Will there be an effect on the levels of soil contamination?
	Will there be an effect on soil erosion and landslides?
	Will there be an effect on geo­di­versity interests (eg GCRs)?