landscape ecology

landscape ecology

the study of the effect of spatial patterns on ecological processes and how those processes in turn create environmental patterns

"the study of the effects of pattern on process"

strong inference

testing a null against many possible alternatives provides the strongest evidence b/c it allows multiple hypotheses to be rejected at once

domains of scale

as one scale changes, scaling relationships are usually not continuous.

mechanisms differ within and outside domains

(Krummel et al. 1987)

scale

spatial or temporal dimension of an object or process, characterized by both grain and extent

grain

the finest level of spatial resolution possible within a given data set (spatial res. cares more about quality instead of quantity)

extent

the size of the study area or the duration of time under condition (how big the picture is, likes size instead of details)

paradigm

preconceived notions, your set of beliefs and values; reflects your culture

hypothesis (null & alternative)

hypothesis has to be falsifiable

null hypothesis- says nothing changed

alternative hypothesis- change happened

you want null hyp. to fail; want to disprove null hyp.

statistics

Collection of methods for planning experiments, obtaining data, organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on data.

paradigm shift

when enough people say their results are contrary to the norm then paradigm change occurs (doesn't change over night, could take years)

scientific revolution

new way of thinking about the natural world based on careful observation and a willingness to question

mu

an alternative answer to yes or no; the grey area in a black and white situation

conceptual evolution

understanding of nature's complexity; is a gradual shift

(Robert Paine 2002)

scientific method

a method of investigation involving observation and theory to test scientific hypotheses

natural experiment

An experiment in which the researcher does not control the situation

(sensu Diamond 1986)

P-value

proportion (or probability) of a certain cover type on a landscape

hypothetico-deductive approach

a proposed description of scientific method

normal science

defines the problems we find interesting so we work on it. We subconsciously suppress the things we think "are a waste of time."

(Thomas Kuhn 1970)

Type I error

null hypothesis is true but you did not think it is; you reject the null hypothesis which is incorrect

thinking something changed when it didn't

Type II error

null hypothesis is false but you think nothing changed; you accept the null hypothesis which is incorrect

something changed but you didn't think it did

autocorrelation vs. stationarity

In statistics, the autocorrelation of a random process describes the correlation between values of the process at different times, as a function of the two times or of the time difference. Stationarity is uniformity of pattern

peer review

the process in which experts in a given field examine the results and conclusions of a scientist's study before that study is accepted for publication.

intellectual chauvinism

people who are not open enough for others ideas and thoughts; do not accept any new data or ideas

control

the standard for comparison in an experiment

experiment

the act of conducting a controlled test or investigation

pseudoreplication

a false replication due to not knowing all the information about a piece of land; not knowing the history of land when trying to perform a replication. Analysis of variance terminology as the testing for treatment effects with an error term inappropriate to hypothesis being considered in manipulative experiments where inferential statistics are used, treatments are not replicated and replicates are not independent.

(Hurlburt 1984)

scaling vs. extrapolation & interpolation

scaling- is transfer of information across scales

extrapolation- the process of estimating, beyond the original observation interval

interpolation- which produces estimates between known observations

landscape

the visible features of an area of land, including the physical elements of landforms, living elements of land cover and transitory elements such as lighting and weather conditions.

patch

continuous region of the same habitat type; cluster of continuous maps cells of the same cover type

matrix

the background land-use type

corridor

a linear landscape elements that provides for movement between habitat patches

boundary

the transition zone between two distinct landscape elements

edge effect

the condition in which, at ecosystem boundaries, there is greater species diversity and biological density than there is in the heart of ecological communities

Aldo Leopold (1933)

"ecological trap"

a location that seems to be high quality habitat but puts the organism at a higher risk of predation.

land use

anthropogenic(man made) feature

e.g. cropland, pasture, urban...

land cover

natural landscape

e.g. forest, wetland....

ecotone

blend of a patch and matrix

(habitat) fragmentation

habitat loss, isolation of habitat remnants, and habitat transformation

disturbance

DISCRETE event in SPACE and TIME that DISRUPTS ecosystem, community or population structure and CHANGES resources, substrate, or the physical enviroment

palynology

the study of pollen and spores

(M. Davis)

sere (& climax community)

sere (seral stage) = each community stage

climax community = self-perpetuating community, not replaced unless disturbed

species-area relationship

the larger the area, the more species it can handle

area-sensitive species

need minimum amount of space to survive or reproduce, of the fragment is smaller than their minimum requirements, they will go extinct

intermediate disturbance hypothesis

diversity (y-axis) & disturbance (x-axis)

effects of disturbance are usually nonlinear

(Connell 1978)

composition

number of patch types represented on a landscape, and their relative abundance (p value)

configuration

the spatial arrangement, position, orientation, or shape complexity of patches on the landscape

connectivity

how patches are linked on the landscape

p

percent land use or cover type

S (richness)

number of land use or land cover types (dominance)

microcosm

small scale fragmentation experiment

e.g. Huffaker- put mites on oranges

mesocosm

medium scale fragmentation experiment

e.g. ECOTRON

shifting mosaic

disturbance creates a mosaic and b/c disturbances reoccur over time, undisturbed areas become disturbed, disturbed areas recover, and so forth

p's the same, but the configuration changes

mosaic

mosaic approach considers amount, placement, and connectivity of landscape

succession (primary & secondary)

succession = change in species composition in an area after disturbance

primary = e.g. no substrate or soil, but a seed bank and it creates new land

secondary = soil already present

extinction debt

the inevitable extinction of many species in coming years as the result of current human activities

(time-lagged effects)

habitat

land use and land cover

for an organism: an area that possesses resources necessary for it to survive and reproduce there

habitat selection

an active choice; not at random in where to live

use vs. availability

use is greater than availability

it is what is selected not always what is preferred

percolation

passive movement of water through the soil

also means connected when looking at landscapes

Markov model

one way to summarize landscape change is to simple tally all the instances, on a cell by cell basis, in which a cell (pixel) changed cover types in that time interval

source & sink

source = where it comes from

usually birth rate is higher than death rate

sink = where it goes to

usually death rate is higher than birth rate

neutral landscape model (NLM)

provides a neutral benchmark that serves as the framework of the interpretation of the real, observed landscape pattern

Pcrit

critical threshold where the landscape goes from fragmented to connected

model (& types)

to provide a framework for comparison across scales where direct empirical work may be difficult or impossible

1. conceptual 2. analytical 3. simulation

4. representational 5. neutral

despotic distribution (DD)

an aggressive ruler, whose followers do the ruler says; the ruler's family separates themselves from the people; wants to live in the good area and forces everyone else to the bad areas

ideal free distribution (IFD)

organisms are "free" to choice the habitat they want to live in and "free" to move from habitat to habitat in their quest to find the best habitat. (crowding can be troublesome)

stationarity

transition probabilities that are assumed to be constant (stay the same over time)

movement (vs. dispersal vs. migration)

movement = any form of motion

dispersal = form of movement that carries mover away from natal site usually for reproductive success

migration = form of movement that consists of a round-trip journey

patch context

patch context within the matrix has profound implications on the patterns observed within the patch/reserve

context involves placement (location) & design

percolation cluster (spanning cluster)

if a cluster of occupied cells reaches from one side of the map to another and the the organism is said to percolate

keystone species

a species that is critical to the functioning of the ecosystem in which it lives because it affects the survival and abundance of many other species in its community

umbrella approach

tends to focus on one species; it is used to represent the other species and the landscape

patch-matrix

patches are viewed as islands being surrounded by an inhospitable matrix; its roots are in island biogeography. It is useful for terrestrial animals but not overall

ecological footprint

is an accounting tool for ecological resources; categories of human consumption are translated into areas of productive land required to provide resources and assimilate waste products.

landscape (3 definitions)

1. the umbrella concept

2. a regional perspective

3. the important of a matrix

heat island

urbanization is occurring mainly on former cropland, so an increase in urbanization usually means a concomitant decrease in agricultural land; this means that more food (for a burgeoning population) must be grown on marginal land, which usually necessitates agricultural intensification

gradient analysis

The most common approach to studying urban ecosystems is a form of a standard approach taken to studying "natural" ecosystems

biotic homogenization

via trade or intentional transport is likely to contribute to the establishment of invasive species

-positive relationship between shipping activity and invasion rate→ exotic species more prevalent than ever before

metapopulation (sensu stricto & sensu lato)

stricto = spatially subdivided population who subpopulation (members w/in a patch) are characterized by winking dynamics and are linked by dispersal

lato (broad sense) = spatially subdivided population

design principles

designed for preservation of maximum richness; based on island biogeography.

e.g. large > small, cluster > isolated, connected > isolated & round > linear

(Diamond 1975)

greedy, rarity & annealing (connectivity) algorithms

greedy- emphasizes richness

rarity- evenness (rare species)

annealing - connectivity

SLOSS

Single Large OR Several Small

the goal is to maximum species richness which is better to save

island biogeography

describes patterns in species richness on islands as a function of island area and isolation (distance from the mainland).

(MacArthur & Wilson 1963, 1967)

landscape continuum

An alternative to the patch-matrix approach.

In landscapes where patches are not discrete or obviously defined, patches may not be easily differentiated from the matrix.

(Sue McIntyre and Richard Hobbs 1994, 1999)

Carl Troll

Introduced the term "landscape ecology", motivated by aerial photography. LE was to understand the relationship among elements within a landscape, in terms of pattern and process, in a holistic fashion

Karl Popper

The British philosopher responsible for the concept of falsifiability.

formalized the hypothetico-deductive method

John Wiens

performed a meta-analysis of papers published in the journey for LE over its first five years. former president of the International Association for LE

most associated with the mosaic approach

Risser et al. 1984 (Allerton park workshop)

served as the organizational moment for this fledgling science in America. It focused on areas that unite landscape and ecology: spatial pattern and ecological process; spatial and temporal scales; the effect of heterogeneity on fluxes and disturbance; changing patterns; and a framework for natural resource management.

Thomas Kuhn

said paradigms cannot be tested b/c they cannot be true or false

wrote The Structure of Scientific Revolution (1970) and defined "normal science"

Robert Paine

famous for keystone species, also came up with conceptual evolution

Krummel et al. 1987

coined the term domains of scale-

as one changes scale, scaling relationships are usually not continuous

Robert Pirsig

developed concept of "mu" (1974)

Frank Golley

first editor of the journal called LE

Richard Forman

known for land mosaics

looked at nestedness in island biogeography

Pickett & White 1985

described terms of a few defining attributes to disturbance

e.g. magnitude, frequency, predictability, synergisms, contagion and feedbacks

Summerville & Crist 2001

wrote a paper about fragmentation saying:

Results may not be as dramatic as anticipated if remaining habitat is high in quality (can offset loss of habitat):

Margaret Davis

pollen studies (palynology) from soil/sediment cores from the bottom of various lakes

Until Davis' work, most studies of succession were conducted within the paradigm of the inherent balance of nature

B. Van Horne

metapopulation: psuedosinks, sinks and sources

density as a misleading indicator of habitat quality

wrote a paper about despotic deposition (DD)

H. Caswell

Neutral Landscape Models

defined NLM as: models of community assembly and diversity structure vs. a model that was neutral with respect to species interactions

Davies et al.

performed a large fragmentation experiment in Wog Wog system in Australia