Schueller NRE 509

What allowed your metapopulation to persist (not crash) even when populations Schueller NRE 509 Lecture 19: went extinct? Landscape Ecology Applied – High enough: ______1. Fragmentation 2. The Design of Reserves and Not too high:______Landscapes

Landscape Ecology APPLIED: Causes of fragmentation? 1. Fragmentation a. What is it/what does it look like? •Natural b. What causes it? - fires, floods, succession c. What are the consequences? •Anthropogenic - Previously continuous NOTICE Variation in patch & habitat is fragmented matrix type, and: into patches within a • Area matrix • Shape • Arrangement (connectivity)

The world’s ongoing fragmentation experiments

Haddad et al. 2015. Habitat fragmentation and its lasting impact on Causes of fragmentation? Earth’s ecosystems. Sci Adv. 1:e1500052 •Natural - fires, floods, succession,… •Anthropogenic

- agriculture, logging, development, oil & gas extraction, mining,…

- fences, roads, powerlines, dams, …

What are the consequences?

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• Largest and longest-running experiment to General findings: Ecological study fragmentation in tropical forests • Increased mortality of mechanisms? • Manaus, Brazil tree species • Started in 1979 • Loss of frugivorous Use your smarts to birds in small fragments • By logging, set up a series of forest patches, • Loss of large predators come up with specific ranging in size from 1 to 100 ha in small fragments hypotheses •Increase in generalist http://pdbff.inpa.gov.br/iarea.html species

What are the implications of fragmentation? 1. AREA effects (fragment size) How large is enough? What does it depend on?

Species-area For example, - Trophic level relationship • Butterflies that move less - Dispersion of Competition = than128 m in their lifetime resources in smaller populations the habitat = increased chance • Mice with home ranges of of extinction about half a hectare.

+ excludes species • Jaguars with home ranges 2 2 with large home of at least 10 km (4 mi ) range

What are the implications of fragmentation? But why do fragments have even fewer 2. EDGE effects species than controls - the same area Physical: altered microclimate within a forest? Biological: - Increased predation - Competition with EDGE edge species

Laurance, et al. 2002. Ecosystem Decay of Amazonian Forest Fragments: a 22-Year Investigation. Conservation Biology 16 (3): 605–618.

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What are the implications of fragmentation? 3. lack of DISPERSAL between fragments What are the implications of fragmentation? Generally: Loss of species that were there before

Why? 1. 2. 3.

Landscape Ecology Applied – Which is a “better” reserve design for diversity? 1. Fragmentation A or B Why? 2. The Design of Reserves and Landscapes Size

Can island biogeography and Number metapopulation theory help manage fragmented landscapes? Proximity

Arrangement

Connectivity p = 1 – e_ c Shape

Reserve design What if they’re not close? Acquire land to connect: create corridors

Are corridors effective?

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Corridors

Tewksbury, Haddad, and others Connected patches had higher movement of animals, pollen, and seeds

“Corridors work as a superhighway for plants • Will corridors still be effective when climate and animals and they use shifts? them a lot” - Haddad • Is just connecting enough to offset habitat loss? Tewksbury, et al.2002. Corridors affect plants, animals, and their interactions in fragmented landscapes. • Is managed relocation the future of conservation? Proceedings of the National Academy of Sciences 99:12923-12926. Haddad, et al. 2003. Corridor use by diverse taxa. Ecology 84 (3): 609–615.

Single Large Or Several Small? Reserve design: How many? The SLOSS debate Single large or several different small

Depends on: • Habitat heterogeneity (Beta diversity) • Minimum viable population size • Dispersal among small • Quality of the Matrix

E.g. different types of agriculture = effect dispersal and edge effects of tropical forest fragments

“Early findings drew our attention to the effects of creating an abrupt edge between forest and adjacent pasture. Over time, most of the cattle Species richness of ground-foraging ants pastures that originally isolated our reserves were in forest fragment >> conventional farm with little shade abandoned and let revert to second-growth forest. = organic farm with shade …we discovered .. the landscape around forest

reserves...can be more important than the size of Perfecto & Vandermeer . 2002. Quality of the reserve in determining what species will be Agroecological Matrix in a Tropical Montane Landscape: Ants in Coffee Plantations in Southern found in an isolated patch of forest.” Mexico. Conservation Biology 16(1): 174-182

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“As the theory states and empirical work confirms, regional extinctions will occur if there is no interfragment migration to The Matrix Matters! The Matrix is… balance the inevitable local extinctions. A focus on the matrix, through which these migrations must occur, is thus required if we are serious about solving the extinction crisis …and that matrix is usually an agroecosystem of some sort.” 2007. Conservation Biology Volume 21, No. 1, 274–277

How would you improve the Recommended reading quality of the matrix? What kind of 0.5 acre suburban backyard or 50 acre agricultural field would: • Increase connectivity (allow for re- colonization events and reduce inbreeding depression) among patches? • Minimize loss of interior/high quality habitat area and reduce edge effects? • Provide a stop-over site or corridor for migratory animals?

At a cocktail party or from a bathroom stall could you talk eloquently about:

• spatial scale • Fragmentation • Immigration • Corridors • Emigration • edge effect • Migration • filter effect • Colonization • Metapopulations • Dispersal • source-sink dynamics • landscape mosaic • island biogeography • species-area relationship • Metacommunity • The matrix (not the movie) • SLOSS debate • connectivity

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