class: center, middle, inverse # Plant coexistence: models for the generation and maintenance of diversity
.footnote[follow along at
wcornwell.github.io
] --- .left-column[ ## What is an community? ] .right-column[ - *Population*: Interacting individuals of the same species - *Community*: Interacting populations of different species - *Ecosystem*: Communities and the environment where they live ] --- class: center, inverse # Gause's competitive exclusion principle
-- ## If two species are using the same thing, one will (eventually) win and the other will go (locally) extinct --- name: how layout: false .left-column[ ] .right-column[ # The paradox ```remark # Angiosperms 304,419 species* --- # Gymnosperms 1,104 species* ``` .slides[ .first[ Gymnos
] .second[ Angios
] ] .footnote[* source [the plant list](http://www.theplantlist.org/)] ] --- class: center, middle, inverse # The paradox of diversity
--- ## A few observations about diversity: Darwin's "abominable mystery": ### Some clades are more diverse than others, even with the same amount of evolutionary time: ```remark # Angiosperms 304,419 species* --- # Gymnosperms 1,104 species* ``` .slides[ .first[ Gymnos
] .second[ Angios
] ] --- ### Some places are more diverse than others, even with the same number of individuals:
1 ha of the Yasuni forest in, Equador, there are 644 tree species --- # The thing we are trying to explain -- "Ecology is the study of the distribution and abundance of organisms" --
--- # All community ecology explanations fall into 4 (and only 4) categories -- ## 1. *Speciation* --- 3 species becomes 4 species -- ## 2. *Dispersal* (immigration) --- An individual arrives from somewhere else -- ## 3. *Drift* --- random increase or decrease in a population -- ## 4. *Selection* --- non-random or "deterministic" increase or decrease in a population --- # All community ecology explanations fall into 4 (and only 4) categories -- ## 1. *Speciation* --- next 10 minutes -- ## 2. *Dispersal* (immigration) --- Covered in later lectures -- ## 3. *Drift* --- Covered in later lectures -- ## 4. *Selection* --- 15 minutes after that --- # Speciation gradients: stop and think 1. What causes speciation? 2. Would that process be more common in some places than others ---
--
--- class: center, middle, inverse ## Evolution: net diversification differences across clades
--- Research in BEES: Poore et al. in press PNAS: herbivore clades are more diverse than their sister groups .left-column[
] .right-column[
] --- ## *Selection* --- non-random or "deterministic" increase or decrease in a population --- class: center, middle, inverse ## Ecological niche differences All plants use the same resources (nutrients, water, light, space) but there still may be spatial or temporal specialization ("niches") in the uptake and use of these resources
--- ##Importance of the regneration niche (Grubb 1977) When an individual dies, it may or may not be replaced by an individual of the same species.
Difference in who wins at that key moment is what matters --- ## 4 Different regeneration/life-cycle traits that may promote co-existence, despite adults using the same resources (*sensu* Gause's competitive exclusion principle) -- 1. Production of viable juveniles (including the sub-stages of flowering, pollination and seed-set), -- 2. dispersal, in space and time, -- 3. growth, -- 4. reproduction. --- class: inverse ## One useful way to categorize species' regneration niches: shade-tolerant versus light-demanding versus shade-demanding
--- class: center, middle, inverse ## From Rainforest to Oil Palms and back again: a Daintree Rainforest Rescue in far north Queensland
--- class: inverse ## The regeneration niche is temporal as well as spatial
--- class: inverse
--- class: center, middle, inverse
< --- class: center, middle, inverse
---
---
--- class: center, middle, inverse
--- # All community ecology explanations fall into 4 (and only 4) categories ## 1. *Speciation* --- 3 species becomes 4 species ## 2. *Dispersal* (immigration) --- An individual arrives from somewhere else ## 3. *Drift* --- random increase or decrease in a population ## 4. *Selection* --- non-random or "deterministic" increase or decrease in a population --- # Within selection: important concepts -- 1. Competitive exclusion principle (Gause) -- 2. Niche in space and time (versus "neutral" processes) -- 3. Regeneration niche (Grubb) -- - Pulses of resources, especially in deserts -- - Fire dynamics (depends on intensity / timing of the fire) -- - Tree fall gaps in forest ecosystems --- class: center, middle, inverse #Next Lecture on Island Biogeography including dispersal and drift ##See you then