Species, Area, & the Equilibrium Theory of Island Biogeography as a foundation paradigm in conservation biology Part 2…

Preserve Design Guidelines

IBT & Design A. Large is better than smallA. Large is better than small B. Undivided is better than dividedB. Undivided is better than divided C. If divided, close is better than farC. If divided, close is better than far D. If divided, distances should be equalD. If divided, distances should be equal E. Corridors are better than no corridorsE. Corridors are better than no corridors F. Circular is better than narrow (low perimeter to area ratio)F. Circular is better than narrow (low perimeter to area ratio)

Size Better Worse

Fragmentation Better Worse

Distance Better Worse

Clustered Better Worse

Connectivity Better Worse

Shape Better Worse

IBT & Design

The SLOSS Debate S ingle L arge O r S everal S mall of the same total area

Several Small > Single Large Florida scrub vertebrates--McCoy & Mushinsky 1994 Butterflies, Spain--Baz & Garcia-Boyera 1996 Plants, Norway--Saetersdal 1994 Plants in mires, Finland--Virolainen et al Birds--Loman & von Schantz 1991

Area Plants Birds From Stohlgren & Quinn 1993

Megareserves for large predators >10 6 ha 100 km linear extent

Simberloff & Abele 1976 Island A becomes Archipelago AIsland A becomes Archipelago A Island B becomes Archipelago BIsland B becomes Archipelago B For A, SS > SLFor A, SS > SL For B, SL > SSFor B, SL > SS

Simberloff & Abele 1976 Area m 2 Spp A A A A38047 A Archipelago A > 77!!

Simberloff & Abele 1976 Area m 2 Spp B B17136 B28732 Archipelago B < 56!!

Immediate Complaints Diamond, Terborgh, Whitcomb Not all spp equalNot all spp equal –Some extinction prone, Total Spp not the best measure of success –Large predators need 100s-1000s km 2 –Colonial nesters, Migrating spp, Spp dependent on core Small reserves loose the same Spp, so become more similar to each other, more overlap, Spp lists are nestedSmall reserves loose the same Spp, so become more similar to each other, more overlap, Spp lists are nested

SLOSS?? It depends! Several Small Species overlap (similarity) among islands Simberloff & Abele 1972

The Diamond IslesThe Diamond Isles The Lack ArchipelagoThe Lack Archipelago The Tallahassee ArchipelagoThe Tallahassee Archipelago

Scale dependence

CONSERVATION STRATEGY Both grain and extent are critical! Grain: Ecological integrity, Population viability Hydrology, Black bears, Vagile species Extent: variation in environment and history Local endemics, Poorly dispersed species Representativeness SLOSS is here to stay because grain & extent maximize different contributions to biodiversity

The Umbrella Concept Protecting large animals that require large areas & play important ecosystem roles --large bird & mammalian predators— protects all species

Does the Umbrella Species Idea Work? Carnivore plan would protect 43% of North American invertebrates No better than random placement Kerr 1997 Plants > birds as the umbrella group for other taxa, S California Ryti 1992 Vertebrates missed lower plant diversity Portugal Araujo 1999 Rare species captured common species; Common species did not capture rare Rebelo & Siegfried 1992

Other island-like models Gene flowGene flow MetapopulationsMetapopulations Landscape ecologyLandscape ecology

Other SLOSS-like debates GLOSS: Is it better to sample genes from one population or from several small populations of the same total size (number of individuals sampled)?GLOSS: Is it better to sample genes from one population or from several small populations of the same total size (number of individuals sampled)? SLOPP: Is it better to protect one large population or several small populations of the same total size?SLOPP: Is it better to protect one large population or several small populations of the same total size? FLOSS: Is it better to introduce a species as one large release or several small releases?FLOSS: Is it better to introduce a species as one large release or several small releases?

Conservation as sampling By definition we conserve a subset of the originalBy definition we conserve a subset of the original What is the best conservation sample?What is the best conservation sample? What are the consequences of fragmentation?What are the consequences of fragmentation? Thing and processThing and process

The Two Triangles The Constraint of Size A continuum of area sensitivity Starting with large predators, 10 6 ha Headwaters of streams Disturbance regimes, pattern and process Dependence on multiple habitats; seasonal movements Exceptions: rare species dependent on rare habitat; air pollution; alien invasions; climate synchronization; long distance migration Size: completeness, wholeness, integrity, health Costs of management and conservation success Conservation as sampling: bigger areas are better samples Feasible restoration goals depend on size BUT any site can play a role…dependent on size

The Two Triangles Continued Small areas Small area requiring species, habitats Connectors, stepping stones Representation: more places Air, Water, Soil quality Environment: temperature Human-nature connections Human well-being