biodiversity conservation in landscape mosaics of central america: segregate or integrate? celia a....

Biodiversity conservation in landscape mosaics of Central

America: Segregate or integrate?

Celia A. Harvey, Center for Applied Biodiversity Science (CABS)

Conservation [email protected]

World Congress of Agroforestry, August 2009

mailto:[email protected]

(

intensive agriculture or pasture

natural forest

integrated, agroforestry landscape: crops, trees, and

forest patchesTree plantations

intensive

extensive

Agr

ofor

estr

y

Agr

icu

ltu

re

F

ores

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Segregate Integrate functions

‘Segregation or Integration’: which are the implications for biodiversity conservation?

?

Key questions

1. How does biodiversity compare across forest, pasture and silvopastoril systems?

2. Within silvopastoril systems, what factors influence patterns of biodiversity?

3. How does the biodiversity within silvopastoril landscapes compare to that of forest landscapes?

Important implications for land planning and conservation efforts

The FRAGMENT project: Understanding the role of silvopastoril landscapes in biodiversity conservation and

farm productivity

Landscape structure and composition

Effects of land use and tree cover on farm productivity

Local knowledge and management of tree cover and agroforestry

Biodiversity present in different land uses and landscape configurations

Opportunities and challenges for conservation and production efforts in silvopastoril landscapes

Rivas, Nicaragua

Cañas, Costa Rica

Rio Frio, Costa Rica

Matiguas, Nicaragua

4 mosaic landscapes (10,000 ha each), dominated by cattle production

(original vegetation= forest)

All four are highly fragmented landscapes, dominated by pastures, but with abundance trees and live fences in pastures

Cañas Río Frío Rivas Matiguás

% pasture 48.4 47.0 56.7 68.2

% secondary forest

15.3 15.9 15.6 6.9

% riparian forest 7.9 6.0 5.9 1.4

Mean tree density in pastures (per ha)

8 23 17 33

Mean density of live fences (m per ha)

108 290 59 160Live fences

Dispersed trees

Biodiversity methods

Riparian forest (RF)

Live fences (LF)

Pastures with low tree cover (< 5%, PL)

Pastures with high tree cover (16-25%, PH)

Forest Fallows (young secondary succession,FF)

Secondary forest (SF)

In each landscape= 6 tree cover types x 8 plots/tree coverIdentical studies in all 4 landscapes

Silvopastoril systems

Sampling efforts (per plot) within forests, pastures and silvopastoril habitats

(sampling effort per plot; see Harvey et al. 2006 for details)

In each landscape:

14,408 trees

12,318 birds

9,648 bats

2,976 butterflies

50,251 dung beetles

What have we learned from the FRAGMENT project that can help us understand the impacts of ‘segregation’ versus ‘integration’ on biodiversity conservation?

intensive agriculture

natural forest

Silvopastoril systems Tree plan-

tationsintensive

extensive

Agr

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0

10

20

30

40

50

60

SF RF FF LF PH PL

tree cover type

# sp

ecie

s birds

bats

dung beetles

butterflies

1. All types of habitats (forests, pastures and silvopastoril systems) are used by animal species...

(SF= secondary forests, RF= riparian forests, FF= forest fallows, LF= live fences,PH=pastures with high tree cover, PL= pastures with low tree cover)

Rivas

CH

CañasCañas

However, there are clear differences in the value of different habitats for different species...

For example, bat diversity was greater in riparian forests (RF) and live fences than in other habitats

Riparian forests

Live fences

Pastures with low tree cover

Bird species richness was also generally higher in habitats with high tree cover, than in habitats with low tree cover

Forests and riparian forests

Forest fallows

Live fencesPastures with low tree cover

(There were also significant differences in species composition)

Matiguas, Nicaragua


natural forest

Integrated agroforestry

systems Agr

ofor

estr

y


What does this suggest for the ‘segregate’ versus ‘integrate’ debate? At the plot level….

Highest priority for conservation: -greatest # of species-more forest-dependent species-more species of conservation concern

Intermediate priority for conservation: -Intermediate to high # species-some forest dependent species-some species of conservation concern

Open pastures: low priority for conservation: -Low species richness-Mainly generalist species- -No species of conservation concern

Agr

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2. What factors influence the biodiversity within individual silvopastoril systems?

Figure 1. Species accumulation curves of birds in complex versus simple live fences(red) in Rio Frio, Costa Rica (Lang et al. 2005)

Complex live fences

Simple live fences

a) Floristic composition and structural complexity

0 3 5 8 10

Mean live fence crown width (m)

0

10

20

30

40

# bi

rd s

pp

Management

Number of bird species in live fences in Rio Frio, Costa Rica as function of crown width (Lang et al. 2003)

81 bird spp.45 bird spp.

b. Management

c) Tree density within the silvopastoril system

Figure 1. Number of species found in pastures with different levels of tree cover (Harvey et al., in prep.)

PL: 0-5% tree cover

PH: 16-25% tree cover

d) the location of the silvopastoril plot within the broader landscape (e.g., closeness and connectivity to forest patches)

N

1 0 1 2

Kilómetros

Parcelas de muestreo

$ Bosque ripario$ Bosque secundario

$ Charral

$ Cerca viva

$ Potrero de alta cobertura

$ Potrero de baja cobertura

Usos del sueloArboles en lineaAsentamientos humanosBosqueBosque riparioCallesCharralesCuerpos de aguaCultivos anuales

No clasificadoPasto alta coberturaPasto baja coberturaPasto media coberturaPlantacionesTacotales

Cultivos perennes

$

$

$

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Área de estudio

Costa Rica

#

Arboles en lineaAsentamientos humanosBosqueBosque riparioCallesCharralesCuerpos de aguaCultivos anualesCultivos perennesNo clasificadoPasto alta coberturaPasto baja coberturaPasto media coberturaPlantacionesTacotales

# Punto de muestreo

100 m

250 m

(Garcia et al., in review)


natural forest

Silvopastoril systems Tree plan-

tationsintensive

extensive

Agr

ofor

estr

y

Agr

icu

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Adding to the segregate versus integrate debate:

Characteristics of the silvopastoril system:-Plant species composition-Structural diversity

-Management (e.g., pollarding)

Landscape context:- Amount of forest nearby-Connectivity to forest patches

?

3. How does the biodiversity within an agroforestry landscape compare to that of intact, forested landscape?

The agroforestry landscape retained a significant portion of the original forest biodiversity

• 68% of bird spp.• 91% of the bat spp.• 68% of dung beetle spp.• 48% of butterfly spp. registered in the Santa Rosa National Park

Agroforestry landscape of Cañas, Costa Rica (10,000 ha)

(48.3 % pastures, 15.3% secondary forest)

0

50

100

150

200

250

birds bats dungbeetles

butterflies

animal group

# sp

ecie

sCanas

Santa Rosa

The rate of species accumulation within agroforestry landscapes may be similar to that of intact forest landscapes (for some taxa), but…

Figure 1. Species accumulation curves for birds in Río Frío agroforestry landscape compared to La Selva Biological Station. (Taylor et al., in prep.)

Rio Frio

(>40% pasture)

La Selva

10 bird species (ranked) most commonly captured in each landscapes

Agroforestry landscape of Río Frío La Selva (intact forest)

Variable Seedeater (Sporophila americana) 1 *Red-capped Manakin (Pipra mentalis)

Clay-colored Robin (Turdus grayi) 2 Ochre-bellied Flycatcher (Mionectes oleagineus)

Passerini’s Tanager (Ramphocelus passerinii) 3 Wedge-billed Woodcreeper (Glyphorynchus spirurus)

Wedge-billed Woodcreeper (Glyphorynchus spirurus)

4 White-collared Manakin (Manacus candei)

Buff-throated Saltator (Saltator maximus) 5 Wood Thrush (Hylocichla mustelina)

Blue-gray Tanager (Thraupis episcopus) 6 *White-throated Manakin (Corapipo altera)

**Tennessee Warbler (Vermvora peregrina) 7 *Bicolored Antbird (Gymnopithys leucaspis)

**House Wren (Troglodytes aedon) 8 Swainson’s Thrush (Catharus ustulatus)

White-collared Manakin (Manacus candei) 9 *White-breasted Wood-Wren (Henicorhina leucosticta)

Blue-black Grassquit (Volatinia jacarina) 10 Orange-billed Sparrow (Arremon aurantiirostris)

…but the species composition may be quite distinct

(Taylor et al., in prep.)














(Taylor et al., in prep.)*Not present in Río Frío captures














(Taylor et al., in prep.)*Not present in Río Frío captures** Not present in La Selva


natural forest

Integrated agroforestry landscapes

Tree plantations

intensive

extensive

Agr

ofor

estr

y

Agr

icu

ltu

re

F

ores

try


Adding to the segregate versus integrate debate:

At the landscape level…

(no landscape data- but plot data suggests that biodiversity would be very depauperate and dominated by generalist species)

Intact forest landscapes have high species richness and more of the original forest taxa…

…while the silvopastoril landscape may have comparable species richness, but more generalist species and fewer forest species

What we still don’t know:

• Within individual silvopastoril systems, are there thresholds of tree density, diversity or connectivity, below which they have little value for biodiversity?

(Most farmers keep tree densities below 25%, to reduce shade- so there are few pastures of higher tree cover available for study)

What we still don’t know (cont’d)• At the landscape level: Are there thresholds in forest cover (area,

connectivity) below which abrupt changes occur in the biodiversity?

• Are there optimal spatial arrangements of forest patches, pastures, and agroforestry systems for biodiversity?

% pasture

% f

ores

t

Matiguas

RivasCanas

Rio Frio

(difficult to find landscapes along the gradient)

??

Conclusions

• While biodiversity conservation in Central America can be best achieved by maintaining existing forest cover, silvopastoril landscape also hold considerable scope for conservation

• It is possible to provide broad principles to guide conservation efforts within silvopastoril landscapes…but we are still far from being able to provide recommendations on the optimal spatial structure and composition

• In addition, we also need to carefully consider how landscape composition, structure and management will impact farm productivity, rural livelihoods, and the provision of other ecosystem services, as there will be both synergies and tradeoffs among different goals.

Key references• Chacón, M. and C. A. Harvey. 2006. Live fences and landscape connectivity in a neotropical

agricultural landscape. Agroforestry Systems, 68: 15-26

• Harvey, C. A. et al. 2005. Contribution of live fences to the ecological integrity of agricultural landscapes in Central America. Agriculture, Ecosystems and Environment, 111: 200-230.

• Harvey, C. A., et al. 2006. Patterns of animal diversity associated with different forms of tree cover retained in agricultural landscapes. Ecological Applications 16(5): 1986-199

• Harvey, C.A. and J.C. Saénz. 2007. Evaluación y conservación de biodiversidad en paisajes fragmentados de Mesoamérica. Editorial UNA, Heredia, Costa Rica.

• Harvey, C.A., et al. 2008 Integrating Agricultural Landscapes with Biodiversity Conservation in the Mesoamerican Hotspot: Opportunities and an Action Agenda. Conservation Biology 22(1):8-15.

• Medina, A., et al. 2007. Bat diversity and movement in a neotropical agricultural landscape. Biotropica, 39(1): 120-128.

• PARTNERS:

Opportunities for enhancing biodiversity conservation within these agricultural

landscapes?

A. Maintain exisiting tree cover (riparian forests, forest patches, fallow areas, live fences and dispersed trees)

- Forest patches and riparian forests key for conservation efforts

- Retain highest # of tree, bird and bat species- Most diverse vegetation types

- Other types of on-farm tree cover play complementary roles

- Provide additional habitat and resources- Help maintain landscape connectivity

B. Increase and diversify tree cover within landscapes

– promote natural regeneration in pastures to replace old or harvested trees

– Increase tree densities within pastures

( Current levels of tree cover within pastures can be increased to at least 20% without affecting pasture production)

-diversify and increase density of live fences

- enhance connectivity at the landscape level by connecting live fences (and other linear features) to remaining forest patches

Converting existing wooden fences to live fences can greatly enhance on-farm tree cover, as well as landscape connectivity

C. Identify activities or management practices that have a negative impact on tree cover and biodiversity conservation promote alternative management practices

- non- sustainable harvesting of firewood and timber from remaining forest patches- indisriminate removal of regenerating trees in pastures

D. Provide incentives, laws and policies that promote on-farm tree management for conservation purposes– Payments for environmental services (carbon, water, biodiversity) – Reforestation incentives– GEF project “Integrated Silvopastoril Approaches to Ecosystem Management” already

successfully applying environmental incentive schemes on cattle farms

biodiversity conservation in landscape mosaics of central america: segregate or integrate? celia a....

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