create_ecospace {ecospace}

Create Ecospace Framework.

Description

Create ecospace frameworks (functional trait spaces) of specified structure.

Usage

create_ecospace(
  nchar,
  char.state,
  char.type,
  char.names = NA,
  state.names = NA,
  constraint = Inf,
  weight.file = NA
)

Arguments

nchar

Number of life habit characters (functional traits).

char.state

Numeric vector of number of character states in each character.

char.type

Character string listing type for each character. See 'Details' for explanation. Allowed types include:

• numeric for numeric and binary characters,

• ord.num for ordered numeric characters,

• ord.fac for ordered factor characters, or

• factor for factor characters.

char.names

Optional character string listing character names.

state.names

Optional character string listing character state names.

constraint

Positive integer specifying the maximum number of "multiple presences" to allow if using multistate binary/numeric character types. The default Inf allows all possible permutations (except for "all absences"). See 'Details' for additional explanation.

weight.file

Data frame (species X trait matrix) or a vector (of mode numeric, integer, or array) of relative weights for ecospace character-state probabilities. Default action omits such probabilities and creates equal weighting among states. If a data frame is supplied, the first three columns must be (1) class [or similar taxonomic identifier], (2) genus, and (3) species names (or three dummy columns that will be ignored by algorithm).

Details

This function specifies the data structure for a theoretical ecospace framework used in Monte Carlo simulations of ecological diversification. An ecospace framework (functional trait space) is a multidimensional data structure describing how organisms interact with their environments, often summarized by a list of the individual life habit characters (functional traits) inhabited by organisms. Commonly used characters describe diet and foraging habit, mobility, microhabitat, among others, with the individual diets, modes of locomotions, and microhabitats as possible character states. When any combination of character states is allowed, the framework serves as a theoretical ecospace; actually occurring life-habit combinations circumscribe the realized ecospace.

Arguments nchar, char.state, char.type specify the number and types of characters and their states. Character names and state names are optional, and assigned using numeric names (i.e., character 1, character 2, etc.) if not provided. The function returns an error if the number of states and names is different than numbers specified in provided arguments.

Allowed character types include the following:

• numeric for numeric and binary characters, whether present/absent or multistate. See below for examples and more discussion on these implementations.

• ord.num for ordered numeric values, whether discrete or continuous. Examples include body size, metabolic rate, or temperature tolerance. States are pulled as sorted unique levels from weight.file, if provided.

• ord.fac for ordered factor characters (factors with a specified order). An example is mobility: habitual > intermittent > facultative > passive > sedentary. (If wish to specify relative distances between these ordered factors, it is best to use an ordered numeric character type instead).

• factor for discrete, unordered factors (e.g., diet can have states of autotrophic, carnivorous, herbivorous, or microbivorous).

Binary characters can be treated individually (e.g., states of present = 1/absent = 0) or can be treated as multiple binary character states. For example, the character 'reproduction' could be treated as including two states [sexual, asexual] with exclusively sexual habits coded as [0,1], exclusively asexual as [1,0], and hermaphrodites as [1,1]. The constraint argument allows additional control of such combinations. Setting constraint = 2 only allows a maximum of "two-presence" combinations (e.g., [1,0,0], [0,1,0], [0,0,1], [1,1,0], [1,0,1], and [0,1,1]) as state combinations, but excludes [1,1,1]; setting constraint = 1 only allows the first three of these combinations; the default behavior (Inf) allows all of these combinations. In all cases, the nonsensical "all-absence" state combination [0,0,0] is disallowed.

Character states can be weighted using the optional weight.file. This is useful so that random draws of life habits (functional-trait combinations) from the ecospace framework are biased in specified ways. If not provided, the default action assigns equal weighting among states. If a vector of mode array, integer, or numeric is provided, character states (or character-state combinations, if multistate binary) are assigned the specified relative weight. The function returns an error if the supplied vector has a length different that the number of states allowed.

If a data frame is supplied for the weight file (such as a species-by-trait matrix, with species as rows and traits as columns, describing a regional species pool), weights are calculated according to the observed relative frequency of states in this pool. If such a data frame is supplied, the first three columns must be (1) class [or similar taxonomic identifier], (2) genus, and (3) species names, although these can be left blank. In all cases, character state probabilities are calculated separately within each character (including only those allowed by the specified constraint).

Value

Returns a list of class ecospace describing the structure of the theoretical ecospace framework needed for running simulations. The list has a length equal to nchar + 1, with one list component for each character, plus a final list component recording constraints used in producing allowable character states.

Each character component has the following list components:

char

character name.

type

character type.

char.space

data frame listing each allowable state combination in each row, the calculated proportional weight (pro), frequency (n) of observed species with such state combination in species pool (weight.file, if supplied).

allowed.combos

allowed character state combinations allowed by constraint and weight.file, if supplied.

The last component lists the following components:

constraint

constraint argument used.

wts

vector of character-state weights used.

pool

species by trait matrix used in assigning character-state weights, if supplied. Note that this matrix may differ from that supplied as weight.file when, for example, the supplied file includes character-state combinations not allowed by constraint]. It also excludes taxonomic identifiers (class, genus, species).

Note

If you have trouble matching the characters with char.state and char.type, see data.frame in first example for easy way to trouble-shoot. If you have trouble supplying correct length of char.name, state.name and weight.file, consider producing an ecospace framework with defaults first, then using these to supply custom names and weights.

Author(s)

Phil Novack-Gottshall [e-mail]

References

Bambach, R. K. 1983. Ecospace utilization and guilds in marine communities through the Phanerozoic. Pp. 719-746. In M. J. S. Tevesz, and P. L. McCall, eds. Biotic Interactions in Recent and Fossil Benthic Communities. Plenum, New York.

Bambach, R. K. 1985. Classes and adaptive variety: the ecology of diversification in marine faunas through the Phanerozoic. Pp. 191-253. In J. W. Valentine, ed. Phanerozoic Diversity Patterns: Profiles in Macroevolution. Princeton University Press, Princeton, NJ.

Bambach, R. K., A. M. Bush, and D. H. Erwin. 2007. Autecology and the filling of ecospace: key metazoan radiations. Palaeontology 50(1):1-22.

Bush, A. M. and R. K. Bambach. 2011. Paleoecologic megatrends in marine Metazoa. Annual Review of Earth and Planetary Sciences 39:241-269.

Bush, A. M., R. K. Bambach, and G. M. Daley. 2007. Changes in theoretical ecospace utilization in marine fossil assemblages between the mid-Paleozoic and late Cenozoic. Paleobiology 33(1):76-97.

Bush, A. M., R. K. Bambach, and D. H. Erwin. 2011. Ecospace utilization during the Ediacaran radiation and the Cambrian eco-explosion. Pp. 111-134. In M. Laflamme, J. D. Schiffbauer, and S. Q. Dornbos, eds. Quantifying the Evolution of Early Life: Numerical Approaches to the Evaluation of Fossils and Ancient Ecosystems. Springer, New York.

Novack-Gottshall, P.M. 2007. Using a theoretical ecospace to quantify the ecological diversity of Paleozoic and modern marine biotas. Paleobiology 33: 274-295.

Novack-Gottshall, P.M. 2016a. General models of ecological diversification. I. Conceptual synthesis. Paleobiology 42: 185-208.

Novack-Gottshall, P.M. 2016b. General models of ecological diversification. II. Simulations and empirical applications. Paleobiology 42: 209-239.

Examples

# Create random ecospace framework with all character types
set.seed(88)
nchar <- 10
char.state <- rpois(nchar, 1) + 2
char.type <- replace(char.state, char.state <= 3, "numeric")
char.type <- replace(char.type, char.state == 4, "ord.num")
char.type <- replace(char.type, char.state == 5, "ord.fac")
char.type <- replace(char.type, char.state > 5, "factor")
# Good practice to confirm everything matches expectations:
data.frame(char = seq(nchar), char.state, char.type)
ecospace <- create_ecospace(nchar, char.state, char.type, constraint = Inf)
ecospace

# How many life habits in this ecospace are theoretically possible?
seq <- seq(nchar)
prod(sapply(seq, function(seq) length(ecospace[[seq]]$allowed.combos)))
# ~12 million

# Observe effect of constraint for binary characters
create_ecospace(1, 4, "numeric", constraint = Inf)[[1]]$char.space
create_ecospace(1, 4, "numeric", constraint = 2)[[1]]$char.space
create_ecospace(1, 4, "numeric", constraint = 1)[[1]]$char.space
try(create_ecospace(1, 4, "numeric", constraint = 1.5)[[1]]$char.space) # ERROR!
try(create_ecospace(1, 4, "numeric", constraint = 0)[[1]]$char.space) # ERROR!

# Using custom-weighting for traits (singletons weighted twice as frequent
#   as other state combinations)
weight.file <- c(rep(2, 3), rep(1, 3), 2, 2, 1, rep(1, 4), rep(2, 3), rep(1, 3),
rep(1, 14), 2, 2, 1, rep(1, 4), rep(2, 3), rep(1, 3), rep(1, 5))
create_ecospace(nchar, char.state, char.type, constraint = 2,
  weight.file = weight.file)

# Bambach's (1983, 1985) classic ecospace framework
# 3 characters, all factors with variable states
nchar <- 3
char.state <- c(3, 4, 4)
char.type <- c("ord.fac", "factor", "factor")
char.names <- c("Tier", "Diet", "Activity")
state.names <- c("Pelag", "Epif", "Inf", "SuspFeed", "Herb", "Carn", "DepFeed",
  "Mobile/ShallowActive", "AttachLow/ShallowPassive", "AttachHigh/DeepActive",
  "Recline/DeepPassive")
ecospace <- create_ecospace(nchar, char.state, char.type, char.names, state.names)
ecospace
seq <- seq(nchar)
prod(sapply(seq, function(seq) length(ecospace[[seq]]$allowed.combos)))
# 48 possible life habits

# Bush and Bambach's (Bambach et al. 2007, bush et al. 2007) updated ecospace
#   framework, with Bush et al. (2011) and Bush and Bambach (2011) addition of
#   osmotrophy as a possible diet category
#   3 characters, all factors with variable states
nchar <- 3
char.state <- c(6, 6, 7)
char.type <- c("ord.fac", "ord.fac", "factor")
char.names <- c("Tier", "Motility", "Diet")
state.names <- c("Pelag", "Erect", "Surfic", "Semi-inf", "ShallowInf", "DeepInf",
  "FastMotile", "SlowMotile ", "UnattachFacMot", "AttachFacMot", "UnattachNonmot",
  "AttachNonmot", "SuspFeed", "SurfDepFeed", "Mining", "Grazing", "Predation",
  "Absorpt/Osmotr", "Other")
ecospace <- create_ecospace(nchar, char.state, char.type, char.names, state.names)
ecospace
seq <- seq(nchar)
prod(sapply(seq, function(seq) length(ecospace[[seq]]$allowed.combos)))
# 252 possible life habits

# Novack-Gottshall (2007) ecospace framework, updated in Novack-Gottshall (2016b)
#   Fossil species pool from Late Ordovician (Type Cincinnatian) Kope and
#   Waynesville Formations, with functional-trait characters coded according
#   to Novack-Gottshall (2007, 2016b)
data(KWTraits)
head(KWTraits)
nchar <- 18
char.state <- c(2, 7, 3, 3, 2, 2, 5, 5, 2, 5, 2, 2, 5, 2, 5, 5, 3, 3)
char.type <- c("numeric", "ord.num", "numeric", "numeric", "numeric", "numeric",
  "ord.num", "ord.num", "numeric", "ord.num", "numeric", "numeric", "ord.num",
  "numeric", "ord.num", "numeric", "numeric", "numeric")
char.names <- c("Reproduction", "Size", "Substrate composition", "Substrate
  consistency", "Supported", "Attached", "Mobility", "Absolute tier", "Absolute
  microhabitat", "Relative tier", "Relative microhabitat", "Absolute food
  microhabitat", "Absolute food tier", "Relative food microhabitat", "Relative
  food tier", "Feeding habit", "Diet", "Food condition")
state.names <- c("SEXL", "ASEX", "BVOL", "BIOT", "LITH", "FLUD", "HARD", "SOFT",
  "INSB", "SPRT", "SSUP", "ATTD", "FRLV", "MOBL", "ABST", "AABS", "IABS", "RLST",
  "AREL", "IREL", "FAAB", "FIAB", "FAST", "FARL", "FIRL", "FRST", "AMBT", "FILT",
  "ATTF", "MASS", "RAPT", "AUTO", "MICR", "CARN", "INCP", "PART", "BULK")
ecospace <- create_ecospace(nchar, char.state, char.type, char.names, state.names,
  constraint = 2, weight.file = KWTraits)
ecospace
seq <- seq(nchar)
prod(sapply(seq, function(seq) length(ecospace[[seq]]$allowed.combos)))
# ~57 billion life habits

ecospace <- create_ecospace(nchar, char.state, char.type, char.names, state.names,
  constraint = Inf)
ecospace
seq <- seq(nchar)
prod(sapply(seq, function(seq) length(ecospace[[seq]]$allowed.combos)))
# ~3.6 trillion life habits