Restoration Ecology and the Conservation of Biodiversity

Restoration Ecology and the Conservation of Biodiversity Basic principles of ecology have practical use for solutions to human problems NRES 420 Restoration Ecology Objectives • Human transformation of landscape created need • Illinois – a state in great need • Restoration ecology & conservation biology • Blending science into practice • Important ecological principles for restoration • Practice of restoration Landscape Transformation 1870‟s Advent of clay drainage tile systems Decreased rail transportation costs Legislation to create drainage districts 1903 First flight 1956 Interstate Highway System 1800 1840 1880 1920 1960 2000 1836 Steel plow invented 1869 Transcontinental railroad 1923 First commercial hybrid maize 1970s Environmental protection legislation 1850 Swamp & Overflowed Lands Act 1893 First gasoline automobile 1862 Homestead Act 1999 Executive Order 13112 (invasive species) Early Settlement 1800 1820 Start of Agriculture 1840 1860 1880 Prairie Drainage 1900 Diversified Farming 1920 1940 1960 Monoculture 1980 Elk Bison Black Bear Mountain Lion Gray Wolf CHANGES IN MAJOR LANDSCAPE ELEMENTS IN ILLINOIS SINCE 1800 AND IMPACTS ON SELECTED MAMMALS Fisher Deer Beaver Bobcat Otter Coyote Hectares (millions) in Illinois 8.0 6.4 4.8 Dry Prairie Wet Prairie / Marsh Forests Pasture 3.2 1.6 0 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 Year Habitat Loss Fragmentation FOREST PARCELS BY AREA CATEGORY NUMBER OF HIGH QUALITY PRAIRIES REMAINING IN ILLINOIS CLASSIFIED BY SIZE CATEGORY >240 120 Area Category (ha) 40-240 Number of Sites 20-40 80 4-20 40 0.4-4 <0.4 0 100 0-0.5 0.5-2 2-4 4-8 8-20 20-40 >40 1,000 10,000 100,000 1,000,000 Prairie Size (ha) Number of Parcels Invasive Species Non-Natives in the Illinois Flora* % of Illinois Flora 30 20 10 0 1846 1950 1986 2004 *2004: 961 non-native of 3,074 taxa 97 of 173 families (56%) lack nonnative taxa Spread of Alliaria petiolata Illinois in Need • Clearly a need – – Remaining habitat: • 0.01% prairie • 9.9% wetland • 31.4% forest – U.S. Rank: • Indiana 48 • Illinois 49 • Iowa 50 Restoration Ecology Using research to better understand ecological processes within highly disturbed ecosystems in order to enhance their complexity and long-term persistence POPULATION ECOLOGY COMMUNITY ECOLOGY RESTORATION ECOLOGY ECOSYSTEM ECOLOGY LANDSCAPE ECOLOGY Ecosystem function Ecosystem structure A. D. Bradshaw, “Reclamation of Land and Ecology of Ecosystem Improving the Ecology of a Disturbed Area by: • Reclamation – increase diversity in highly disturbed system • Rehabilitation – reintroduction of ecosystem function • Restoration – reestablishment of functions and characteristic species, communities, and structure • Reconstruction – starting restoration from scratch van Diggelen, Grootjans & Harris (2001) Restoration Ecology Applying ecological principles within a social context to revitalize habitats and conserve species POLICY POPULATION ECOLOGY COMMUNITY ECOLOGY SOCIETY ECOLOGICAL RESTORATION ECONOMICS ECOSYSTEM ECOLOGY LANDSCAPE ECOLOGY POLITICS What is your idea about Restoration? • “…like rearranging the deck chairs on the Titanic” • “…a forgery of nature” • “…seeks to construct nature like a museum diorama” • “…same as restoring an antique tractor” • „…a kind of intellectual junkpicking” Ecology Theory Relevant to Restoration • Population Ecology – Vulnerability of small populations • Genetic depression, swamping • Metapopulation theory + MVP size • Community Ecology • Species-area relationships – Island biogeography theory – Problems with fragmented habitats • Intermediate disturbance hypothesis • Succession & community assembly • Diversity-stability theory • Landscape Ecology • Ecosystem Ecology Population Ecology • Species survival depends on • maintaining minimum viable population levels (>500). • maintaining genetic diversity. • using locally adapted genotypes. How do the size & genetic diversity of a founding population influence the establishment, growth, & evolutionary potential of the population? Local ecotypes for soil type? How much genetic diversity is needed in the founding population? Nursery Ecotype? How much influence does local adaptation have on population success? Will non-local seed sources pollute the local population? Or will they enhance diversity & reduce inbreeding? Species-Area Curve S = c + z log A S = c Az log S = log c + z log A Island Biogeography Theory Immigration Extinction Small Large Near Number of Species Far Patch relationships: What is take-home message? (From Forman, 1995) Ecological Disturbance: Dimensions 1 2 3 (D.T. Krohne, „General Ecology‟) Intermediate Disturbance Hypothesis Competitive exclusion Disturbance Rate Small species pool Selected Natural & Anthropogenic Disturbances • Natural Events** – – – – – – – – – • Anthropogenic Events** – – – – – – – – – Residential development Road, trail, railroad line Telephone line, electrical power line Dam, water diversion, canal Commercial development Modern agriculture Mining Logging Grazing Fire Disease epidemic Flood Herbivory Drought Hurricane, tornado, windstorm Avalanche, landslide Volcanic eruption Ice storm ** Entries in italics connote reversible disturbances; others represent long-term or permanent conversion of habitat. Succession • an orderly change in relative abundances of dominant species in a community following a disturbance until a stable community („climax‟like predisturbance) results  1° succession begins on mineral soils  2° succession begins on soils with seeds • Influence of facilitation, inhibition, & tolerance on community development – Facilitation – early species make environment less suitable for themselves, but more suitable for later species -- nurse crops Succession: Species-Species Interactions - Tolerance - early species make environment less suitable for recruitment of similar early species, but they neither help nor hinder later species - Inhibition - early species make environment inhospitable to later-arriving species Early prairie reconstructions overly dominated by warm season grasses Community Assembly • development of the ecological community is determined by random variation in species' colonization of a disturbed area & subsequent species interactions Succession vs. Community Assembly • Succession – Deterministic – Internal interactions & environment determine outcome • Assembly – Stochastic – Supply of propagules determines outcome – Multiple stable assemblies Hierarchy of Succession General causes Site availability Species availability Contributing processes Disturbance Dispersal Propagules Resources Modifying factors Size, severity, time, dispersion Landscape configuration, dispersal agents Land use, time since last disturbance Soil, topography, site history Germination requirements, assimilation rates, growth rates, genetic differentiation Allocation, reproductive timing & mode Climate, site history, prior occupants Competition, herbivory, resource availability Soil chemistry, microbes, neighboring species Climate, predators, plant defenses & vigor, community patchiness Species performance Ecophysiology Life history Stress Competition Allelopathy Herbivory Restoration: Managing Succession Designed Disturbance Managing Succession Controlled Colonization Controlled Species Performance Managing Succession: in Practice Designed Disturbance Controlled Colonization Controlled Species Performance Burning Bulldozing, Scraping, Topsoil Mixing Cabling Burning Broadcast seeding, Drill seeding, Direct planting Cutting Burning Cabling Grazing, Excluding grazers Chopping, Clipping Flooding & draining Herbicide application Plowing Solarization (thermal shock) Soil compaction Grazing Fertilization, Herbicide spraying Irrigation, Water level change Topsoiling & live soiling Rotovating Scraping Soil fabrics Fertilization, Reducing soil fertility Herbicide application Mowing, Selective cutting Irrigation, Water level change Diversity/Complexity/Stability • An increase in the structural diversity of vegetation increases species diversity. Full restoration of native plant communities sustains diverse wildlife populations. A high diversity of plant species assures a year-round food supply for the greatest diversity of wildlife • • Landscape Ecology • How does the landscape context of the restoration influence everything discussed earlier? Spatial Principles • • • • • • • • Large areas sustain more species than small areas. Many small patches in an area will help sustain regional diversity. Patch shape is as important as size. Fragmentation of habitats, communities, and ecosystems reduces diversity. Isolated patches sustain fewer species than closely associated patches. Species diversity in patches connected by corridors > than for disconnected patches. A heterogeneous mosaic of community types sustains more species & is more likely to support rare species than a single homogeneous community. Ecotones between natural communities support a variety of species from both communities & species specific to the ecotone. Minimum Dynamic Area in Restoration Design  Largest patch size  Patch longevity  Disturbance frequency  Habitat requirements Ecosystem Ecology Interactions between the biotic & abiotic components of the ecosystem