1. Ainhoa Magrach, Asier R. Larrinaga, Luis Santamaria
Changes in Patch Features May Exacerbate or Compensate for the Effect of Habitat Loss on Forest Bird Populations
Ainhoa Magrach, Asier R. Larrinaga, Luis Santamaria

2. Chiloe Islands Chile has many islands Second largest island on Chile
Temperature and humid climate
Evergreen trees with understory of vines,
epiphytes and bamboos
Darwin listed Chiloe as island covered with one
great forest but not anymore
Reduction of forests by 41% after 1999

3. Why Study – Habitat fragmentation
“A state of discontinuity in the spatial distribution of resources and conditions that affects occupancy, reproduction, or survival in a particular set of species”
Direct and indirect consequences
Complex mechanism consisting of:
Patch area – area of the patch
Isolation – distance between the patches
Patch shape – major contributor of habitat Fragmentation
Edge effects – effect of side by side contrast of different habitats
Internal characteristics of patches – tree size and epiphyte abundance

4. Elaenia
Chucao
Hummingbird
Rayadito
Blackbird
Thrush

5. Methods Studied species 80% of total avifauna of Chilean forest
Seed dispersal and pollination: Study system
Chucao – understory bird, limited dispersal. Do not go into open habitat
Elaenia – migrant, main seed disperser
Hummingbird – main pollinator and most abundant. Found in surrounded matrix and all over the forest
Rayadito – large tree user. Dispersal decreases when patches not connected by forest
Blackbird – near the edges
Thrush – frugivores, forest and bush areas
Bird survey :
Surveys in 22 forest fragments at least 2 hec
Cue – count point surveys
Eat forest patch divided into 8 census points. List birds seen or heard in 10 minutes
Epiphyte surveys:
Angiosperm epiphytes on all the census points
Produces fleshy fruits that birds eat
Landscape and patch metrics
Statistical analyses

7. Results Point – level bird densities Changes at landscape scale
Patch – level bird densities
Abundance for four species except thrush and blackbird determined by patch isolation
Patch shape had major effects on chucao, hummingbird and elaenia
Habitat characteristics only affected chucao
Patch area did not affect any species
Point – level bird densities
Hummingbird density increased from edge to center
elaenia density increased with epiphyte abundance
Changes at landscape scale
Reduction of forest lead to smaller, isolated and less irregular patches
Negative effect on elaenia population
No effect on chucao population
Positive effect on hummingbird population
Patch shape and isolation major factors that determine the bird densities in austral rainforests
Internal features of patches only affected hummingbirds and chucao
Effect of deforestation ranged from negative, balanced to positive

8. Chucao densities declined with increasing patch elongation and isolation Elaenia densities higher in more irregularly- shaped patches and in less isolated ones hummingbird density increased with decreasing patch elongation

9. No effect on population
Distributed all over the
Study sites
Abundance
In clusters
Decreased population
Due to changes in
landscape
Increased population
Bird moved to patches
Where it was not earlier

10. Citation
Magrach A, Larrinaga AR, Santamarıa L (2011) Changes in Patch Features May Exacerbate or Compensate for the Effect of Habitat Loss on Forest Bird Populations.