4. 3 Name of the Indicator: Abundance of key species Description of the indicator




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4.3 Name of the Indicator: Abundance of key species

1. Description of the indicator (objective, methodological general aspects and utility):

This indicator aims to evaluate temporal and spatial trends in the abundance of key species. The goal is to collect useful information in order to make decisions concerning use of the sites in the MPA. This indicator allows establishing comparisons among different MPAs with common species.



2. Measurement unit of the indicator:

Categories of abundance of key species, where:

Single (S) = 1 individual

Few (F) = 2-10 individuals

Many (M) = 11-100 individuals

Abundant (A) = more than 100 individuals



3. Methodological description:

Prior steps to implement the indicator:

  1. Select sites and species to monitor based on the following criteria: (1) they are highly attractive to tourists, (2) they are threatened or endangered, (3) they have reduced distribution ranges, (4) they can be reached or touched by tourists, (5) their watching season or areas are coincident with courtship, mating, birth or feeding activities, (6) they are easy to see and frequent to encounter. The higher the numbers of criteria accomplished by a species, the most appropriate it is as a focal species. Limit the list of species to those that are really important for tourism, trying to keep a low number of key species (it is recommended the number is not higher than 20 and focuses mainly on mega-fauna).

  2. Try to include all visitors’ sites. If this is not possible, at least include the most frequently visited and the less frequently visited, ideally with similar biophysical characteristics which can be useful for comparisons.

  3. Use abundance categories suggested instead of counts of number of individuals. These categories are standardized for fish counts (http://www.reef.org)

  4. Design field forms to collect data (see Appendix 1).

  5. Design the database to store and process collected data. Use a friendly software such as Excel (see Appendix 2)

  6. Carry out continuous monitoring of species abundance at the selected visitor’ sites. This should be carried out at least one a month at each site, so that temporal comparisons are consistent

  7. With the data collected, temporal comparisons (among months and years) and spatial comparisons (among sites or among MPAs) can be performed. Data should be entered into a database and periodically analyzed to assess any existing trend. For an example of data interpretation see Appendix 3.

3.1. Process to calculate the indicator (steps):

This indicator is formed by two parameters: Density Index (DEN) and Sighting Frequency (%SF).


Density Index (DEN): is a measure of how many individuals of each species are observed based on a scale of 1 to 4, which represents the abundance category that was registered more frequently for the species when it was observed. Values of the abundance categories are: Single=1, Few=2, Many=3, y Abundant=4. For example, DEN = 2.2 indicates that a given species was more frequently observed at category 2 (Few) but because DEN is higher than 2, it can be deduced that there were also records of that species at categories 3 and 4.
Sighting frequency (%SF): is a measure of how frequent a species is observed. Indicates the percentage of times a species is registered in relation to the total number of times monitoring was carried out.
By multiplying the sighting frequency (%SF) by the density index (DEN), based on the equation presented on section 3.2, an estimate of the relative abundance of the species per site can be obtained, at any desired temporal scale (month, year, etc)

3.2. Formula of the indicator (in case this is useful to simplify the indicator measurement):

Density index (Den):




(S * 1) + (F * 2) + (M * 3) + (A * 4)

Den = ----------------------------------------------------------------------------

(Number of times monitoring took place)



Sighting frequency (%SF):


S + F + M + A (for each species)

%SF = 100 * ------------------------------------------------

(Total monitoring)





3.3. Presentation of the results (graphs, figures, tables, etc. that allow visualizing the results clearer):

With the obtained values comparative bar graphs can be made, of the abundance of each species and of all species evaluated at each site, as well as per month and per year. It is also possible to make graphs based on the %SF values which can be useful to decide where to take visitors according to their expectations, i.e.: if they are interested in sharks, take them to sites where %SF is higher for shark species.



3.4. Possible methodological limitations of the indicator:

This indicator can be biased by environmental variables (both meteorological and oceanographic), as well as by the change of observer. It is necessary that the observer has an adequate knowledge of the selected species for monitoring



4. Variation and influence ranges:

4.1. Relation with other indicators:

This indicator can relate directly or indirectly to other indicators, such as:

- Number of introduced and invasive species

- Negative visual impact factors in the visit sites

- Behavioral reactions in key mega-fauna to human behavior

- Average evaluation score in different aspects of the visit

- Number of visits to the protected area and its sites
5. Data availability:

5.1. Are there available data? (Yes) (No) In which format/state are they? (Printed, digital, field data sheets, analyzed, published, etc):

There is a digital database for Galápagos Marine Reserve, but not analyzed. There is some data collected for SFF Malpelo, partially analyzed. There is no data for PNN Gorgona



6. Responsible institutions of the indicator (including potential ones):

Management of the MPA, tourism operators



7. References related to the indicator:

Adult, E. y G.J. Edgar (Eds.). 2002. Reserva Marina de Galápagos. Línea Base de la Biodiversidad. Fundación Charles Darwin/Servicio Parque Nacional Galápagos, Santa Cruz, Galápagos, Ecuador. 484 pp.

Plan básico de manejo 2005-2009, Parque Nacional Natural Gorgona. 2004. Parques Nacionales Naturales de Colombia. Dirección Territorial Suroccidente. Cali (Valle). 229 p.

Plan básico de manejo 2005-2009, Santuario de Fauna y Flora Malpelo. 2004. Parques Nacionales Naturales de Colombia. Dirección Territorial Suroccidente. Cali (Valle). 126 pp

http://www.reef.org/data/interpret.htm

8. Comments (methodological limitations included):

Methods are adapted of those used by The Reef Environmental Education Foundation - REEF



Fecha: February 2007 Autor: Luis Chasqui Velaso

E-mail: lchasqui@hotmai.com

APPENDIX 1
MONITORING OF DIVE SITES AT PNN GORGONA

Mark “X” in the cell that corresponds to the abundance (# of individuals) estimated by species


Key species for tourism

No

sighting

Single

(1)

Few

(2-10)

Many

(11-100)

Abundant (>100)

Octopus
















Sea cucumbers (Holothuroidea)
















Black urchin (Diadema sp.)
















Pencil urchin (Hesperocidaris sp.)
















Seastars (Asteroidea)
















Puffers (Arothron sp.)
















Boxfish (Ostracion sp.)
















Butterfly fish (Chaetodontidae)
















Trigger fish (Balistidae)
















Goliath grouper (Epinephelus itajara)
















Groupers (Serranidae)
















Parrotfish (Scaridae)
















Angel fish (Pomacanthidae)
















Moorish idol (Zanclus cornutus)
















Morays (Muraenidae)
















Porcupine fish (Diodontidae)
















Flounders (Bothidae)
















Tuna fishes (Scombridae)
















Barracudas (Sphyraenidae)
















Surgeon fish (Acanthuridae)
















Snappers (Lutjanus sp.)
















Jacks (Caranx sp.)
















Amber jacks (Seriola rivoliana)
















Whitetip reef shark (Triaenodon obesus)
















Whale shark (Rhincodon typus)
















Devil Manta (Manta birostris)
















Eagle ray (Aetobatus sp.)
















Hawksbill turtle
















Black turtle
















Marine mammals (sp., # ind., prof.):

Odd species (sp, #, prof.):


Data collected by: _____________________________________________________________________________
APPENDIX 2


Year

Month

Site

Entry time

Exit time

Weather

Sea

Current

Visibility (m)

Temp (˚C)

Depth (m)

Seriola rivoliana

Rhyncodon Typus







































NS = not sightings

S = single

F = few


M = many

A = abundant



APPENDIX 3

*Example of data interpretation for each species (Tropical Eastern Pacific)

.


Den

%SF

Interpretation

Den HIGH
>3.0

%SF

HIGH >50



Species is often observed and observed at high densities. Species is seen > 50% of the time and when it is seen the abundance category most often recorded is M or A. Species example: yellowfin damselfish

Den

HIGH >3.0



%SF LOW <50

Species is not often seen, but when it is seen, it is observed at high densities. Species is seen < 50% of the time and when it is seen the abundance category most often recorded is M or A. Species example: garden eel

Den

LOW <3.0


%SF

HIGH >50


Species is often observed, but always at low densities. Species is seen > 50% of the time and when it is seen the abundance category most often recorded is F or S. Species examples: Pacific trumpet fish, three-banded butterfly fish

Den

LOW <3.0


%SF LOW <50

Species is not often observed and when it is observed, it is at very low densities. Species is seen < 50% of the time and when it is seen the abundance category most often recorded is F or S. Species example: zebra moray

From http://www.reef.org/data/interpret.htm



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