990 resultados para Alien Species
Resumo:
Artemisio annuae-Conietum maculati ass. nova is described from the lower valley of Llobregat and Bess rivers. Communities of this association, which is included into the Silybo-Urticion Sissingh 1950 alliance, are hygronitrophilous meadows up to 3 m high and more than 80% of vegetation cover. They are commonly restricted to the river bed and are made up almost exclussively by therophytes and hemicryptophytes. However, the mostcharacteristic trend of these herbaceous communities is the abundance of neophytes, which stand for 20% of the species but close to 50% of vegetation cover. Several widespread neophytes such as Aster squamatus, Conyza spp., Xanthium spp. are commonly found in these communities, and other rare aliens such as Artemisia annua, Rumex cristatus and R. palustris have recently been recorded. Ecological implications of the neophyte abundance in these communities are discussed in relation to the role of human disturbance and population biology of alien species in general.
Resumo:
Despite the increase of animal and plant introductions worldwide and the strong augmentation of the reptile trade, few invasive snake populations have been studied. Dice snakes (Natrix tessellata) were introduced to the shores of Lake Geneva (Switzerland) in the early 1920s, and are now well established. This region of introduction was previously inhabited by Viperine snakes (N. maura). Ever since these two species have been under monitoring (which began in 1996) the Viperine snake population has shown drastic decline. We examine here the possibility of trophic competition by analysing diet composition, prey size and trophic niche overlap. Spatial distribution is also assessed in order to address the question of spatial competitive exclusion. We found very similar diets, and thus a high trophic niche overlap, indicating no partitioning of the trophic resource. No arguments in favour of spatial competitive exclusion were found. Our study suggests that trophic competition may occur between the two natricines and that it may give an explanation for the drastic decline of the Viperine snake in this area. Other pathways potentially playing a role in the exclusion of the Viperine snake are discussed.
Resumo:
On Chichijima, one of the Ogasawara (Bonin) Islands located in the Western Pacific Ocean, land snails have declined, the suggested cause being predation pressure by an invasive flatworm (Platydemus manokwari). Soil fauna were investigated in areas where the snail survives, and where it has become extinct. Much of the fauna, dominated by introduced earthworms and ants, was undiminished, however, one undescribed but endemic carabid (Badister sp.), which selectively feeds on land snails, was absent in snail-extinct areas. The invasive flatworm P. manokwari has been reported to feed also on the carcasses of earthworms, as well as on live snails, and is therefore expected to occur in most parts of Chichijima Island. Among other groups, the density of isopods (also dominated by exotic species) was very low, in comparison with the reported ones 30 years ago. Community structure is currently reflected by dominance of earthworms and ants, decline of endemic isopods, and a high frequency of introduced or alien species.
Resumo:
Suomenlahden lisntynyt meriliikenne on herttnyt huolta meriliikenteen turvallisuuden tasosta, ja erityisesti Venjn ljyviennin kasvu on lisnnyt ljyonnettomuuden todennkisyytt Suomenlahdella. Erilaiset kansainvliset, alueelliset ja kansalliset ohjauskeinot pyrkivt vhentmn merionnettomuuden riski ja meriliikenteen muita haittavaikutuksia. Tm raportti ksittelee meriturvallisuuden yhteiskunnallisia ohjauskeinoja: ohjauskeinoja yleisell tasolla, meriturvallisuuden keskeisimpi stelijit, meriturvallisuuden ohjauskeinoja ja meriturvallisuuspolitiikan tulevaisuuden nkymi, ohjauskeinojen tehokkuutta ja nykyisen meriturvallisuuden ohjausjrjestelmn heikkouksia. Raportti on kirjallisuuskatsaus meriturvallisuuden yhteiskunnalliseen sntelyn rakenteeseen ja tilaan erityisesti Suomenlahden meriliikenteen nkkulmasta. Raportti on osa tutkimusprojektia SAFGOF - Suomenlahden meriliikenteen kasvunkymt 2007 - 2015 ja kasvun vaikutukset ympristlle ja kuljetusketjujen toimintaan ja sen typakettia 6 Keskeisimmt riskit ja yhteiskunnalliset vaikutuskeinot. Yhteiskunnalliset ohjauskeinot voidaan ryhmitell hallinnollisiin, taloudellisiin ja tietoohjaukseen perustuviin ohjauskeinoihin. Meriturvallisuuden edistmisess kytetn kaikkia nit, mutta hallinnolliset ohjauskeinot ovat trkeimmss asemassa. Merenkulun kansainvlisen luonteen vuoksi meriturvallisuuden sntely tapahtuu posin kansainvlisell tasolla YK:n ja erityisesti Kansainvlisen merenkulkujrjestn (IMO) toimesta. Lisksi mys Euroopan Unionilla on omaa meriturvallisuuteen liittyv sntely ja on mys olemassa muita alueellisia meriturvallisuuden edistmiseen liittyvi elimi kuten HELCOM. Joitakin meriturvallisuuden osa-alueita sdelln mys kansallisella tasolla. Hallinnolliset meriturvallisuuden ohjauskeinot sisltvt aluksen rakenteisiin ja varustukseen, alusten kunnon valvontaan, merimiehiin ja merityn tekemiseen sek navigointiin liittyvi ohjauskeinoja. Taloudellisiin ohjauskeinoihin kuuluvat esimerkiksi vyl- ja satamamaksut, merivakuutukset, P&I klubit, vastuullisuus- ja korvauskysymykset sek taloudelliset kannustimet. Taloudellisten ohjauskeinojen kytt meriturvallisuuden edistmiseen on melko vhist verrattuna hallinnollisten ohjauskeinojen kyttn, mutta niit voitaisiin varmasti kytt enemmnkin. Ongelmana taloudellisten ohjauskeinojen kytss on se, ett ne kuuluvat pitklti kansallisen sntelyn piiriin, joten alueellisten tai kansainvlisten intressien edistminen taloudellisilla ohjauskeinoilla voi olla hankalaa. Tieto-ohjaus perustuu toimijoiden vapaaehtoisuuteen ja yleisen tiedotuksen lisksi tieto-ohjaukseen sisltyy esimerkiksi vapaaehtoinen koulutus, sertifiointi tai meriturvallisuuden edistmiseen thtvt palkinnot. Poliittisella tasolla meriliikenteen aiheuttamat turvallisuusriskit Suomenlahdella on otettu vakavasti ja paljon tyt tehdn eri tahoilla riskien minimoimiseksi. Uutta sntely on odotettavissa etenkin liittyen meriliikenteen ympristvaikutuksiin ja meriliikenteen ohjaukseen kuten meriliikenteen shkisiin seurantajrjestelmiin. Mys inhimilliseen tekijn merkitykseen meriturvallisuuden kehittmisess on kiinnitetty lisntyviss mrin huomiota, mutta inhimilliseen tekijn osalta tehokkaiden ohjauskeinojen kehittminen nytt olevan haasteellista. Yleisimmin lkkeeksi esitetn koulutuksen kehittmist. Kirjallisuudessa esitettyjen kriteereiden mukaan tehokkaiden ohjauskeinojen tulisi tytt seuraavat vaatimukset: 1) tarkoituksenmukaisuus ohjauskeinojen tytyy olla sopivia asetetun tavoitteen saavuttamiseen, 2) taloudellinen tehokkuus ohjauskeinon hydyt vs. kustannukset tulisi olla tasapainossa, 3) hyvksyttvyys ohjauskeinon tytyy olla hyvksyttv asianosaisten ja mys laajemman yhteiskunnan nkkulmasta katsottuna, 4) toimeenpano ohjauskeinon toimeenpanon pit olla mahdollista ja sen noudattamista tytyy pysty valvomaan, 5) lateraaliset vaikutukset hyvll ohjauskeinolla on positiivisia seurannaisvaikutuksia muutoinkin kuin vain ohjauskeinon ensisijaisten tavoitteiden saavuttaminen, 6) kannustin ja uuden luominen hyv ohjauskeino kannustaa kokeilemaan uusia ratkaisuja ja kehittmn toimintaa. Meriturvallisuutta koskevaa sntely on paljon ja yleisesti ottaen merionnettomuuksien lukumr on ollut laskeva viime vuosikymmenien aikana. Suuri osa sntelyst on ollut tehokasta ja parantanut turvallisuuden tasoa maailman merill. Silti merionnettomuuksia ja muita vaarallisia tapahtumia sattuu edelleen. Nykyist sntelyjrjestelm voidaan kritisoida monen asian suhteen. Kansainvlisen sntelyn aikaansaaminen ei ole helppoa: prosessi on yleens hidas ja tuloksena voi olla kompromissien kompromissi. Kansainvlinen sntely on yleens reaktiivista eli ongelmakohtiin puututaan vasta kun jokin onnettomuus tapahtuu sen sijaan ett se olisi proaktiivista ja pyrkisi puuttumaan ongelmakohtiin jo ennen kuin jotain tapahtuu. IMO:n tyskentely perustuu kansallisvaltioiden osallistumiseen ja sntelyn toimeenpano tapahtuu lippuvaltioiden toimesta. Kansallisvaltiot ajavat IMO:ssa pasiallisesti omia intressejn ja sntelyn toimeenpanossa on suuria eroja lippuvaltioiden vlill. IMO:n kyvyttmyys puuttua havaittuihin ongelmiin nopeasti ja ottaa sntelyss huomioon paikallisia olosuhteita on johtanut siihen, ett esimerkiksi Euroopan Unioni on alkanut itse sdell meriturvallisuutta ja ett on olemassa sellaisia alueellisia erityisjrjestelyj kuin PSSA (particularly sensitive sea area erityisen herkk merialue). Merenkulkualalla toimii monenlaisia yrityksi: toisaalta yrityksi, jotka pyrkivt toimimaan turvallisesti ja kehittmn turvallisuutta viel korkeammalle tasolle, ja toisaalta yrityksi, jotka toimivat niin halvalla kuin mahdollista, eivt vlit turvallisuusseikoista, ja joilla usein on monimutkaiset ja epmriset omistusolosuhteet ja joita vahingon sattuessa on vaikea saada vastuuseen. Ongelma on, ett kansainvlisell merenkulkualalla kaikkien yritysten on toimittava samoilla markkinoilla. Vastuuttomien yritysten toiminnan mahdollistavat laivaajat ja muut alan toimijat, jotka suostuvat tekemn yhteistyt niiden kanssa. Vlinpitmtn suhtautuminen turvallisuuteen johtuu osaksi mys merenkulun vanhoillisesta turvallisuuskulttuurista. Verrattaessa meriturvallisuuden sntelyjrjestelm kokonaisuutena tehokkaiden ohjauskeinoihin kriteereihin, voidaan todeta, ett monien kriteerien osalta nykyist jrjestelm voidaan pit tehokkaana ja onnistuneena. Suurimmat ongelmat lienevt sntelyn toimeenpanossa ja ohjauskeinojen kustannustehokkuudessa. Lippuvaltioiden toimeenpanoon perustuva jrjestelm ei toimi toivotulla tavalla, josta mukavuuslippujen olemassa olo on selvin merkki. Ohjauskeinojen, sek yksittisten ohjauskeinojen ett vertailtaessa eri ohjauskeinoja keskenn, kustannustehokkuutta on usein vaikea arvioida, mink seurauksena ohjauskeinojen kustannustehokkuudesta ei ole saatavissa luotettavaa tietoa ja tuloksena voi olla, ett ohjauskeino on kytnnss pienen riskin eliminoimista korkealla kustannuksella. Kansainvlisen tason meriturvallisuus- (ja merenkulku-) politiikan menettelytavoiksi on ehdotettu mys muita vaihtoehtoja kuin nykyinen jrjestelm, esimerkiksi monitasoista tai polysentrist hallintojrjestelm. Monitasoisella hallintojrjestelmll tarkoitetaan jrjestelm, jossa keskushallinto on hajautettu sek vertikaalisesti alueellisille tasoille ett horisontaalisesti ei-valtiollisille toimijoille. Polysentrinen hallintojrjestelm menee viel askeleen pidemmlle. Polysentrinen hallintojrjestelm on hallintotapa, jonka puitteissa kaikentyyppiset toimijat, sek yksityiset ett julkiset, voivat osallistua hallintoon, siis esimerkiksi hallitukset, edunvalvontajrjestt, kaupalliset yritykset jne. Kansainvlinen lainsdnt mrittelee yleiset tasot, mutta konkreettiset toimenpiteet voidaan ptt paikallisella tasolla eri toimijoiden vlisess yhteistyss. Tmn tyyppisiss hallintojrjestelmiss merenkulkualan todellinen, kansainvlinen mutta toisaalta paikallinen, toimintaymprist tulisi otetuksi paremmin huomioon kuin jrjestelmss, joka perustuu kansallisvaltioiden keskenn yhteistyss tekemn sntelyyn. Tllainen muutos meriturvallisuuden hallinnassa vaatisi kuitenkin suurta periaatteellista suunnanmuutosta, jollaisen toteutumista ei voi pit kovin todennkisen ainakaan lyhyell thtimell.
Resumo:
Puutarhoista karanneet jttiputket, jttipalsami ja kurtturuusu ovat levinneet laajalti luontoon koko Suomessa. Nm lajit ovat luonnon monimuotoisuutta ja elinympristjen viihtyisyytt uhkaavia vieraslajeja. Jttiputket uhkaavat mys suoraan ihmisen terveytt. Lounais-Suomessa aloitettiin niden lajien jrjestelmllinen kartoitus ja kytnnn torjunta jo vuodesta 2008 alkaen. Aiemmista vieraslajihankkeista vuosina 2008-2010 on saatu merkittvsti tietoa jttiputkien, jttipalsamin ja kurtturuusun torjunnasta. Hankkeissa testattiin erilaisia torjuntamenetelmi, kuten kasvien kitkent, kaivamista juurineen, peittmist pressuilla ja kemiallista ksittely. Hankkeissa seurattiin eri torjuntatapojen tehokkuutta ja laskettiin niiden kustannuksia. Mys torjuntatyn jrjestmisen eri tapoja, kuten urakointi, torjuntatiimi ja talkoot, on seurattu ja niiden kustannuksia arvioitu. Tm raportti esitt Varsinais-Suomen ELY-keskuksen toiminta-alueella saatuja kokemuksia ja paikallisesti hyvksi havaittuja toimia jttiputkien, jttipalsamin ja kurtturuusun levimisen estmisess, mys vieraslajien torjunnasta aiheutuneita kustannuksia. Toivomme, ett raportti antaa evit vieraskasvilajien torjunnan suunnitteluun muilla alueilla ja auttaa arvioimaan toimintaan liittyvi kustannuksia. Raportti on osa Maa- ja metstalousministerin rahoittamaa ja useamman organisaation yhteistyn toteuttamaa Havina-hanketta (Haitallisten vieraslajien hallinta ja tietoisuuden lisminen).
Resumo:
This study is a part of the Ecologically Friendly Port Ust-Luga (EFP) project. The purpose of this study is to examine the environmental status of the Finnish ports and, more specifically, the Port of HaminaKotka. An analysis of the environmental status is performed mainly as a literature review, because the Finnish ports must comply with Finnish and EU legislation and with the binding international regulations and conventions created by different organizations. The International Maritime Organisation (IMO) has done groundbreaking work in the field of maritime safety and maritime environmental protection. The MARPOL convention has a great impact on decreasing pollution from international shipping and it applies to 99% of the worlds merchant tonnage. Pollution prevention covers: Oil pollution, Chemical pollution, Air pollution and GHG Emissions, Dumping of Wasted and Other Matters, Garbage, Sewage, Port Reception Facilities, Special Areas under MARPOL and Particularly Sensitive Sea Areas. There is also Pollution Prevention for other treaties like anti-fouling systems used on ships, the transfer of alien species by ships ballast water and the environmentally sound recycling of ships. There are more than twenty different EU and international regulations that influence ports and port operations in Finland. In addition, there is also national legislation that has an effect on Finnish ports. For the most part, the legislation for ports is common in the EU area, but the biggest and most important difference between the legislation in Finland and other EU countries is due to the Act on Environmental Impact Assessment Procedure. The Act states that the environmental impact assessment procedure shall be applied to projects that may have significant adverse environmental impacts, due to the special features of Finland`s nature and environment. In this Act, the term environmental impact refers to the direct and indirect effects inside and outside Finnish territory of a project or operations on human health, living conditions and amenity; soil, water, air, climate, organisms, interaction between them and biodiversity; community structure, buildings, landscape, townscape and cultural heritage; utilization of natural resources. In Finland, the Environmental Permit requires that ports collect all necessary information concerning environmental effects and make required reports to the Finnish authorities, stakeholders and the public. Commonly, environmental reporting is public and environmental achievements are emphasized in reporting and in media. At the moment, the problem in environmental reporting is that its difficult to compare data from different ports. There is enough data concerning the environmental effects and performance, but the manner of reporting and the quality of the data varies between ports. There are differences in the units and codes used, in some cases the information is not sufficient and it can even be rather unreliable. There are also differences regarding the subjects that are emphasized in reporting.
Resumo:
Alien plants are known to occur in Brazil since the 18th century when African grasses started to be recorded in pastures near Rio de Janeiro. In the beginning of the 19th century two royal decrees (July, 1809 and July, 1810) offered grants and tax exemption to everyone who would introduce plants of economic value. Nowadays, there are 117 plant species recognized as invasive or established and with invasive potential in Brazil and an unknown number of introduced plant species. Some of the most pervasive invasive species are Artocarpus heterophyllus Lam. and Hedychium coronarium Knig in tropical ombrophilous forest, Hovenia dulcis Thunb. in subtropical ombrophilous forest and subtropical semi-deciduous forest, Pinus taeda L. and Pinus elliottii Engelm. in subtropical ombrophilous forest and steppe, Prosopis juliflora (Sw.) DC. in stepic-savanna, Tecoma stans (L.) Juss. ex Kunth in tropical and subtropical semi-deciduous forest, Melinis minutiflora P. Beauv. in the Brazilian savannas, and Eragrostis plana Nees in the steppe. The purpose of this article is to fill a knowledge gap on alien species that are invasive in Brazil and where they are invading by summarizing data obtained by joint efforts of the Hrus Institute for Environmental Conservation and Development, The Nature Conservancy (TNC), the Inter-American Biodiversity Information Network (IABIN) invasive species thematic network (I3N), and the Brazilian Ministry of Environment (MMA) in the last six years.
Resumo:
We tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms, and nests are easily mimicked because they are scrapes containing no vegetation. The study was conducted in the spring of 2001 in forest and fallow fields of central Spain in Castilla La Mancha, Ciudad Real. We used 384 clutches of natural eggs that were white, white spotted, brown, or brown spotted. Within clutches, eggs were consistent in color and size; among clutches, color differences were distributed across habitats. Clutches were checked once after 2 wk of exposure. Cryptic coloration had a survival advantage that was dependent on the local suite of predators. Rodent predation was nonselective with respect to clutch color; however, avian predation was significantly higher for conspicuous clutches. In addition, there was an interaction of landscape and egg color for avian predation. In forest landscapes, the clutches with highest survival were brown spotted, whereas in fallow landscapes, brown and brown spotted clutches had higher survival than white and white potted clutches. Thus, both the predator suite and the landscape had significant effects on the value of cryptic egg coloration. Our study is relevant for conservationists and managers in charge of restocking programs in hunting areas. The release of other partridge species or their hybrids could result in hybridization with wild partridges, potentially leading to nonoptimal clutch pigmentation and reduced survival of the native species. We therefore recommend that local authorities, managers, and conservationists be cautious with the use of alien species and hybrids and release only autochthonous species of partridges within their natural ranges.
Resumo:
It is now accepted that some human-induced climate change is unavoidable. Potential impacts on water supply have received much attention, but relatively little is known about the concomitant changes in water quality. Projected changes in air temperature and rainfall could affect river flows and, hence, the mobility and dilution of contaminants. Increased water temperatures will affect chemical reaction kinetics and, combined with deteriorations in quality, freshwater ecological status. With increased flows there will be changes in stream power and, hence, sediment loads with the potential to alter the morphology of rivers and the transfer of sediments to lakes, thereby impacting freshwater habitats in both lake and stream systems. This paper reviews such impacts through the lens of UK surface water quality. Widely accepted climate change scenarios suggest more frequent droughts in summer, as well as flash-flooding, leading to uncontrolled discharges from urban areas to receiving water courses and estuaries. Invasion by alien species is highly likely, as is migration of species within the UK adapting to changing temperatures and flow regimes. Lower flows, reduced velocities and, hence, higher water residence times in rivers and lakes will enhance the potential for toxic algal blooms and reduce dissolved oxygen levels. Upland streams could experience increased dissolved organic carbon and colour levels, requiring action at water treatment plants to prevent toxic by-products entering public water supplies. Storms that terminate drought periods will flush nutrients from urban and rural areas or generate acid pulses in acidified upland catchments. Policy responses to climate change, such as the growth of bio-fuels or emission controls, will further impact freshwater quality.
Biosecurity in agriculture: an economic analysis of coexistence of professional and hobby production
Resumo:
One component of biosecurity is protection against invasive alien species, which are one of the most important threats worldwide to native biodiversity and economic profitability in various sectors, including agriculture. However, agricultural producers are not homogeneous. They may have different objectives and priorities, use different technologies, and occupy heterogeneous parcels of land. If the producers differ in terms of their attitude towards invasive pests and the damages they cause, there are probably external effects in the form of pest spread impacts and subsequent damages caused. We study such impacts in the case of two producer types: profit-seeking professional producers and utility-seeking hobby producers. We show that the hobby producer, having first set a breeding ground for the pest, under-invests in pest control. We also discuss potential policy instruments to correct this market failure and highlight the importance of considering different stakeholders and their heterogeneous incentives when designing policies to control invasive alien species.
Resumo:
Hot spots of endemism are regarded as important global sites for conservation as they are rich in threatened endemic species and currently experiencing extensive habitat loss. Targeting pre-emptive conservation action to sites that are currently relatively intact but which would be vulnerable to particular human activities if they occurred in the future is, however, also valuable but has received less attention. Here, we address this issue by using data on Endemic Bird Areas (EBAs). First, we identify the ecological factors that affect extinction risk in the face of particular human activities, and then use these insights to identify EBAs that should be priorities for pre-emptive conservation action. Threatened endemic species in EBAs are significantly more likely to be habitat specialists or relatively large-bodied than non-threatened species, when compared across avian families. Increasing habitat loss causes a significant increase in extinction risk among habitat specialists, but we found no evidence to suggest that the presence of alien species/human exploitation causes a significant increase in extinction risk among large-bodied species. This suggests that these particular human activities are contributing to high extinction risk among habitat specialists, but not among large-bodied species. Based on these analyses, we identify 39 EBAs containing 570 species (24% of the total in EBAs) that are not currently threatened with severe habitat loss, but would be ecologically vulnerable to future habitat loss should it occur. We show that these sites tend to be poorly represented in existing priority setting exercises involving hot spots, suggesting that vulnerability must be explicitly included within these exercises if such sites are to be adequately protected.
Resumo:
Hot spots of endemism are regarded as important global sites for conservation as they are rich in threatened endemic species and currently experiencing extensive habitat loss. Targeting pre-emptive conservation action to sites that are currently relatively intact but which would be vulnerable to particular human activities if they occurred in the future is, however, also valuable but has received less attention. Here, we address this issue by using data on Endemic Bird Areas (EBAs). First, we identify the ecological factors that affect extinction risk in the face of particular human activities, and then use these insights to identify EBAs that should be priorities for pre-emptive conservation action. Threatened endemic species in EBAs are significantly more likely to be habitat specialists or relatively large-bodied than non-threatened species, when compared across avian families. Increasing habitat loss causes a significant increase in extinction risk among habitat specialists, but we found no evidence to suggest that the presence of alien species/human exploitation causes a significant increase in extinction risk among large-bodied species. This suggests that these particular human activities are contributing to high extinction risk among habitat specialists, but not among large-bodied species. Based on these analyses, we identify 39 EBAs containing 570 species (24% of the total in EBAs) that are not currently threatened with severe habitat loss, but would be ecologically vulnerable to future habitat loss should it occur. We show that these sites tend to be poorly represented in existing priority setting exercises involving hot spots, suggesting that vulnerability must be explicitly included within these exercises if such sites are to be adequately protected.
Resumo:
Pollinators are a key component of global biodiversity, providing vital ecosystem services to crops and wild plants. There is clear evidence of recent declines in both wild and domesticated pollinators, and parallel declines in the plants that rely upon them. Here we describe the nature and extent of reported declines, and review the potential drivers of pollinator loss, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them. Pollinator declines can result in loss of pollination services which have important negative ecological and economic impacts that could significantly affect themaintenance of wild plant diversity, wider ecosystemstability, crop production, food security and human welfare.
Resumo:
The impacts of current and future changes in climate have been investigated for Irish vegetation. Warming has been observed over the last two decades, with impacts that are also strongly influenced by natural oscillations of the surrounding ocean, seen as fluctuations in the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. Satellite observations show that vegetation greenness increases in warmer years, a feature mirrored by increases in net ecosystem production observed for a grassland and a plantation forest. An ensemble of general circulation model simulations of future climates indicate temperature rises over the twenty-first century ranging from 1C to 7C, depending on future scenarios of greenhouse gas emissions. Net primary production is simulated to increase under all scenarios, due to the positive impacts of rising temperature, a modest rise of precipitation and rising carbon dioxide concentrations. In an optimistic scenario of reducing future emissions, CO2 concentration is simulated to flatten from about 2070, although temperatures continue to increase. Under this scenario Ireland could become a source of carbon, whereas under all other emission scenarios Ireland is a sink for carbon that may increase by up to three-fold over the twenty-first century. A likely and unavoidable impact of changing climate is the arrival of alien plant species, which may disrupt ecosystems and exert negative impacts on native biodiversity. Alien species arrive continually, with about 250 dated arrivals in the twentieth century. A simulation model indicates that this rate of alien arrival may increase by anything between two and ten times, dependent on the future climatic scenario, by 2050. Which alien species may become severely disruptive is, however, not known.
