SPECIES

DIVERSITY-Ecology-

Species diversity

INTRODUCTION(Palarca)

Species diversity

• Species- Largest group of organisms capable of interbreeding and producing fertile offspring.

• Diversity- A state of being diverse or variety. - A range of different things.

Species diversity

SPECIES DIVERSITY

- number or variety of species in a particular region.

Species diversity

- number of different species that are represented in a given community (a dataset)

-incorporates both the number of species in acommunity (species richness)and theevenness of species‘ abundances.

How many species are there?

Species diversity

Types of Species(Estose&Rabongue)

Species diversity

3 Types of Species:

• Endemic species - is one whose habitat is restricted to a particular

area; often endangered

- differs from “indigenous,” or “native,” (although itoccurs naturally in an area, is also found in otherareas.)

Species diversity

2 Types of Endemic Species:

• paleoendemic

-confined to just one area.

• neoendemic species.

-two populations evolve differently, because theycannot interbreed with one another, and eventuallythey are sufficiently different from one another to beclassified as separate species.

Species diversity

• Exotic Species-is any species intentionally or accidentallytransported and released by man into anenvironment outside its present range.

-most severe agents of habitat alteration anddegradation, and major cause of the continuing lossof biological diversity throughout the world.

• Cosmopolitan Species

-Pertinent or common to the whole world.

-Cosmopolitan distributions can be observed both in extinct and extant species.

Species diversity

Factors Affecting

Species Diversity(Corona)

Species diversity

Speciation-is the evolutionary process by which new biological species arise.

4 modes:

1. Allopatric- speciation that occurs when biologicalpopulations of the same species become isolated fromeach other to an extent that prevents or interferes withgenetic interchange.

Species diversity

• Parapatric

– relationship between organisms whose ranges donot significantly overlap but are immediatelyadjacent to each other; they only occur togetherin a narrow contact zone.

Species diversity

• Peripatric

– formation of new species through evolution.

Species diversity

Species diversity

• Sympatric

– is the process through which new species evolvefrom a single ancestral species while inhabitingthe same geographic region.

Species diversity

2 causes of Speciation:

• Geographic Isolation

– populations were prevented from interbreeding by geographic isolation.

– rivers change course, mountains rise, continents drift, organisms migrate.

Species diversity

Geographic isolation

Species diversity

• Reduction of Gene Flow

– a population extends over a broad geographicrange, and mating throughout the population isnot random. Individuals in the far west wouldhave zero chance of mating with individuals in thefar eastern end of the range.

Species diversity

Species diversity

• Extinction-is defined as “the reduction of a species to such low abundance that, although it is still present in the community, it no longer interacts significantly with other species.

Causes:

Taking for Profit

Hunting and Trapping

Overharvesting

Introduced Species

Destruction of Habitat

Pollution

Species diversity

Spotted Visayan Deer

Philippine Eagle

• Migration

- is the moving of individuals of a species from one place to another

• Immigration

- is the migration seen as the settling in one region (permanently or temporarily) of individuals coming from another region.

• Emigration

- is the migration seen as an exit of individuals from one region (to another where they will settle permanently or temporarily).

Species diversity

Positive impacts of alien

invasive species(Imperial)

Species diversity

• Helps to keep the environment in a naturalbalance

- an ecosystem which is species-rich is more resilientand adaptable to external stress than one in whichthe range of species is limited.

- In a system where species are limited, the loss ortemporary reduction of any one could disrupt acomplex food chain with serious effects on otherspecies in that same system.

Species diversity

• Provide beneficial products

- tropical rainforests, in particular, have providedmany beneficial products, from naturalmedicines to biological control agents foragriculture.

• Food

- access to a wide variety of species and geneswithin those species can be used to meet thechanging needs of the worlds population in manyways, by using techniques such as selective breedingcrossbreeding or even genetic manipulation.

Species diversity

Negative impacts of alien

invasive species(Salva , Jabol, Visto, Ebcas,Acle)

Species diversity

Invasive species

Species diversity

-is an organism that causes ecological or economic

harm in a new environment where it is not native.

Here are some ways invasive species impact native ecosystems:

• Habitat modification• Compete with native species for resources• Predation of native species• Herbivory on native plants• Bring in pathogens• Hybridize with natives, leading to loss of genetic diversity

• Economic

– loss or reduced efficiency of production.

– the introduction and spread of alien invasivespecies can have major implications for tradewhich will depend on the policy response oftrading partners.

• Predators

-reduce the population sizes of native species, oreven drive them extinct, because native prey speciesmay not have evolved defenses against the novelpredators

Species diversity

• Genes

- If introduced or spread into habitats with closelyrelated species, alien invasive species couldinterbreed with native species resulting in changesto the genetic makeup of either species

• Hybridization:

- species' genetic compositions can changedrastically by mating with closely related species,making the less common species extinct byhybridization.

Species diversity

• Species- Alien invasive species can influence species diversity,

richness, composition and abundance.

- At the species level, direct effects of alien invasivespecies occur through processes such as;

a. Predation

b. Competition

c. Pathogens/diseases

d. Parasite transmission to individual organisms

*eventually leading to population declines and speciesextinctions

Species diversity

• Habitats

- through their impacts on species andecosystem processes, alien invasive species canresult in;

a. Fragmentation

-is the process by which habitat loss results in thedivision of large, continuous habitats into smaller, moreisolated remnants.

Species diversity

b. Destruction

-is the process in which natural habitat is renderedfunctionally unable to support the species present.

c. Alteration

-is a change in land

d. Complete replacement of habitats

*which in turn affects pecies and ecosystem processes.

Species diversity

• Ecosystems

-the impacts of alien invasive species at theecosystem level include changes to;

a. trophic structures

b. changes in the availability of resources

- water

- nutrients

c. changes in the disturbance regimes.

Species diversity

• Social and Health

- a loss of food sources and traditionalmedicines may be experienced therebycompromising not only the health of local peoplebut also the livelihoods of those dependent on thecollection and sale of such items for income.

Species diversity

Measuring Species Diversity

(Awa & Andrino)

Species diversity

• Species Richness

-the number of species that live in a certain

location.

- a count of species, and it does not take into account the abundances of the species or their relative abundance distributions.

- only residents are counted

- treats common and rare species with the same weight

Species diversity

Desert Lizard Diversity

Lizard Species Number of

Individuals

Cnemidophorus tesselatus 3

Cnemidophorus tigris 15

Crotophytus wislizenii 1

Holbrookia maculata 1

Phrynosoma cornutum 10

Scleoporus magister 2

TOTAL Individuals 32

Desert Lizard DiversityLizard Species Number of

Individuals

Cnemidophorus tesselatus 3

Cnemidophorus tigris 15

Crotophytus wislizenii 1

Holbrookia maculata 1

Phrynosoma cornutum 10

Scleoporus magister 2

TOTAL Individuals 32

Species Richness

Species of Dogs

Species diversity

• Relative abundance

- also known as “Heterogeneity of Species”

-is the number of individuals of each species.

-refers to how common or rare a species is relative to other species in a defined location

Species diversity

Desert Lizard Diversity

Lizard Species Number of

Individuals

Cnemidophorus tesselatus 3

Cnemidophorus tigris 15

Crotophytus wislizenii 1

Holbrookia maculata 1

Phrynosoma cornutum 10

Scleoporus magister 2

TOTAL Individuals 32

Lizard Species Number of

Individuals

Cnemidophorus tesselatus 3

Cnemidophorus tigris 15

Crotophytus wislizenii 1

Holbrookia maculata 1

Phrynosoma cornutum 10

Scleoporus magister 2

TOTAL Individuals 32

Species RelativeAbundance

Desert Lizard Diversity

Formulas:

• Shannon Wiener Index:s

H’ = -∑pi logepi

i=l

H’ = Value of SW diversity index.

pi = Proportion of the ith species.

loge = Natural logarithm of pi.

s = Number of species in community.

Species diversity

• Shannon-Wiener diversity function

H' = - (pi) [ln(pi)]

H’ = Shannon-Wiener index of species diversity

s = number of species in community

pi = proportion of total abundance represented by ith species

Species diversity

Hotspots for Species Diversity

Species diversity

• The hottest spots for species diversity

are tropical rainforests.

Tropical rainforests comprise of only 7% of all land on Earth, yet are home to nearly 50% of all the species on Earth!