第１回JBONワークショップ

2009.05.08

東大駒場キャンパス

Hiroaki IKEDA and Hiroaki IKEDA and ShoriShori YAMAMOTOYAMAMOTOResearch Project for Agro-biodiversity AssessmentNational Institute for Agro-Environmental Sciences, JAPAN

Positive and negative relationships Positive and negative relationships between agricultural activities and between agricultural activities and

biodiversity in rice paddy landscapes biodiversity in rice paddy landscapes of Japanof Japan

MARCO Symposium 2012 / Plenary Session 1 (Tsukuba EPOCHAL, Sept. 25th, 2012)

1. The Status of Biodiversity in/around Farmlands of JapanThe 2020 Target of CBD (Aichi Biodiversity Targets) Four Crises for BiodiversityYear-to-year Changes in Agricultural Environment

2. Relationships between Agriculture and Biodiversity in Rice Paddy Landscapes of Japan

Negative Effects of Agriculture on BiodiversityPositive Effects of Agricultural Landscapes on Biodiversity

- Landscape mosaic through agricultural activitiesPositive Effects of Environment-friendly Farming on Biodiversity

CONTENTSCONTENTSCONTENTS

Convention on Biological DiversityConvention on Biological Diversity

CBDCBD--COP10 was held in Japan, Oct. 2010.COP10 was held in Japan, Oct. 2010.Three objectives of CBDThree objectives of CBD

1) Conservation of biological diversity2) Sustainable use of its components3) Fair and equitable sharing of the benefits (ABS)

Aichi Biodiversity Target (The Strategic Plan) Aichi Biodiversity Target Aichi Biodiversity Target (The Strategic Plan)(The Strategic Plan)

Strategic goal B:

Reduce the direct pressures and promote sustainable use.

Target 7: By 2020 areas under agriculture, aquaculture and forestry are managed sustainably, ensuring conservation of biodiversity.

Crises of Biodiversity Crises of Biodiversity (The National Biodiversity Strategy 2010)

1. Increase of Human Activities: Overuse-

Urbanization, land developments, etc.

2. Decrease of Human Activities: Underuse-

Satoyama (woodland/grassland rural areas) or paddy fields

3. New Crisis-

Alien species, chemical material use, etc.

4. Climate Change

Crises of Biodiversity in JapanCrises of Biodiversity in Japan

4

Many common species in rural areas have become endangeredMany common species in rural areas have become endangeredPaddy fields Semi-natural forest Semi-natural grassland

LanduseLanduse changes in Japanchanges in Japan

0

10

20

30

40

50

60

1975 1980 1985 1990 1995 2000 2005 2010Year

Are

a (1

03 k

m2 )

0

2

4

6

8

10

12

Aba

ndo

ned

area

(%)

Farmland area

Abandoned area

% Abandoned area

Areas of farmlands and abandoned farmlandsAreas of farmlands and abandoned farmlands

• Farmland area in Japan has been decreasing year by year.• Abandoned area has been increasing since the mid 1980s.

– The reduction of food self-sufficiency rate– The governmental policy of reducing cultivation acreage from 1971

Land improvements in JapanLand improvements in Japan

Land improvements of paddy fieldsLand improvements of paddy fields

• Land readjustment for the use of heavy agricultural machinery• Installing irrigation ditches, drainages and farm roads• Installing under-drainages to make well-drained systems

Before After

http://www.maff.go.jp/kyusyu/nn/kouka/gaiyo/04.html

Land improvements in JapanLand improvements in Japan

Percent of improved paddy fieldsPercent of improved paddy fields

• Percent of improved paddy fields has increased since the 1960s.• The area of improved paddy fields reached 60% in the 2000s, and

since then the percent of improvements has been leveled off.

Agricultural Intensification in JapanAgricultural Intensification in Japan

Use of agricultural chemicalsUse of agricultural chemicals

• Before the 1980s, the amount of chemical fertilizers and pesticides use had increased.

• Since the late 1980s, the amount of their use has decreased gradually.– Efficiency improvement by product developments– Impact levels of these chemicals on wildlife would be comparable.

0

5

10

15

20

25

30

35

40

45

1960 1970 1980 1990 2000 2010

Year

Inpu

t pe

r cro

p-pl

ante

d ar

ea

(t/km

2)

Fertilizers

Pesticides

AgricultureAgriculture

＋

sustainable use

＋

habitat supply

－

over chemical use

－

over development

－

diseases, pests

＋

variety of crop

＋ natural enemy＋ matter cycle

BiodiversityBiodiversity

Relationships between Agriculture & Biodiversity

Relationships between Relationships between Agriculture & BiodiversityAgriculture & Biodiversity

Negative Effects on Wading BirdsNegative Effects on Wading Birds• Amano et al. (2010, 2012)

investigated population changes of wading birds (snipes and plovers) using nationwide survey data in Japan between 1975 and 2008.

• In autumn, the populations of paddy field-dependent species increased by the mid 1980s, but decreased gradually to present.

• In autumn, the populations of species that are NOT dependent on paddy fields fluctuated over time, but have not declined.

• This pattern was not seen in spring.

Spring

Autumn

Geo

met

ric m

ean

of p

opul

atio

n in

dice

s

Year

These findings suggest the negative impact of land improvements on wading birds in paddy fields of Japan, because the improved rice fields have no/less water in autumn and winter.

Paddy field-dependent birds

Paddy field-independent birds

Paddy field-independent birds

Negative Effects on Aquatic PlantsNegative Effects on Aquatic Plants

These results indicate the negative impact of herbicide on aquatic plants distributed in paddy fields of Japan.

Effects of a rice herbicide, bensulfuronEffects of a rice herbicide, bensulfuron--methylmethyl

Azolla japonica(free-floating fern)

Salvinia natans(free-floating fern)

Test plants

Penthorum chinense (emergent dicot)

Toxic conc. (μg/L)

2.0(EC50)

0.22(EC50)

1.6(Acceptable

Conc.) River: 0-1 µg/L

Paddy field:>100 µg/L

Drainage:1-10 µg/L

Exposed concentration (μg/L)

All species tested will be extinct

80 0 80 160 m N

Agricultural activities form landscape mosaic, which promotes biAgricultural activities form landscape mosaic, which promotes biodiversity.odiversity.Legend

Paddy fieldUpland fieldDeciduous forest (secondary)Coniferous forest (plantation)Bamboo BushGrasslandMarshy grasslandGreenhouseOther open spacePondChannelHousePavement & road

Positive Effects of AgriculturePositive Effects of AgriculturePositive Effects of Agriculture

Landscape of paddy field with stream, grass, and forest

Relationship between butterfly species richness and landscape structure

High species richness

forest edge

grassland by cutting

edge species

Zephyrus

grassland species

fritillary

Positive Effects on Butterflies Positive Effects on Butterflies

Habitatsupply

Land Use on Another-side of Census Root(P) ● ● ●

(A) ● ●

(U) ● ● ● ●

(S)* ● ● ● ● ● ● ●

(G) ● ● ● ● ● ●

(F) ● ● ● ●

(E)** ●

(P) Paddy rice field 18 25 23 24 12 25 7 43 29 36 37 2 13 21(A) Abandoned paddy 23 18 17 16 9 16 20 25 23 8 21(M) Rice + Abandoned paddy 34 24 11 11(U) Upland field 8 5 15 24 13 10 20(F) Forest 16(G) Grassland in slope 15* Stream, ** Others.

Land Use onOne-sideof Census Root

Positive Effects on Birds Positive Effects on Birds • Amano et al. (2008)

investigated the effects of landscape structure on the species richness and the abundance of birds in rice paddy areas of central Japan.

• Agricultural wetland species particularly utilized rice fields in summer, but open water in winter.

• It is important to maintain a combination of rice fields and open water to satisfy multiple habitat requirements by agricultural wetland species throughout the year.

• The importance of temporal landscape complementation

Impo

rtanc

e of

land

scap

e ty

pe

Agricultural wetland species

Agricultural upland species

Ricefield

Fallowfield

Forest Openwater

Forestedge

Habitatdiversity

SummerWinter

Landscape type

EnvironmentEnvironment--friendly farming includes various practices...friendly farming includes various practices...Plant flowers in field margins

Biological weed control (ducks)Weed control with paper mulch

Weed control with rubber mulch

Biological pest control (pheromone)

Biological weed control (green mulch)

We focused on We focused on no pesticide applicationno pesticide application..from MAFF Japan HP

Effects of Environment-friendly FarmingEffects of EnvironmentEffects of Environment--friendly Farmingfriendly Farming

• Amano et al. (2011) used the abundance data of Tetragnatha spiders, a good indicator of farming practices, in 230 rice fields of Japan.

• Bayesian hierarchical models to predict the abundance of spiders for various pesticide applications with explanatory variables of site-specific factors.

Predicted abundance of Tetragnatha spiders per swing of a sweep net(A) Conventional farming (1 insecticide to fields and to nursery boxes + 3 herbicides)

(B) Environment-friendlyfarming (no pesticides)

Farming Practices on Farming Practices on TetragnathaTetragnatha SpidersSpiders

Survey fields(n = 230)

Tetragnatha caudiculaTetragnatha caudicula

It is important that the effectiveness of environment-friendly farming on biodiversity varies across regions.

Dependence on SiteDependence on Site--specific Factorsspecific Factors

It is important that the effects of environment-friendly farming on spider abundance can be altered by precipitation.

• Amano et al. (2011) also assessed the impact of site-specific factors on the effectiveness of environment-friendly farming on Tetragnatha spiders:

– Temperature– Precipitation– Elevation– Forest area

• Spider abundance was increased with reducing number of pesticide applications.

• This increase was particularly high in areas with high precipitation.

Increase

50% values forall 4 variables

50% values forall 4 variables

CONCLUSIONSCONCLUSIONSCONCLUSIONS1) The relationships between agriculture and biodiversity in rice paddy

landscapes of Japan suggest that farmland improvements and the use of pesticides have negative effects on biodiversity, but agricultural activities also form landscape mosaic which promotes biodiversity through landscape complementation.

2) It is important to sustain agricultural activities for maintaining the landscape mosaic with making a possible effort to minimize negative impacts of farming practices on biodiversity.

3) One option for that would be further extension of environment-friendly farming.

4) The effectiveness of environment-friendly farming practices for biodiversity conservation depended on landscape structure as well as on climatic factors, and environment-friendly farming would be increased more efficiently by taking those into account.

Thank You !Thank You !