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
Instructor/Guide ____________________ Operator ___________________ Ship/Boat _________________
Date: _____________ Site: _________________________________ Time: ______ entry ______ exit
# groups/boat _______ # divers/group _______ # groups/site _______ Max Depth (m) _______
Current (direction)
___________________ Superficial
___________________ at _____ m
Nule
Soft
Moderate
Strong
Weather
Sunny
Cloudy
Drizzle
Rain
Sea
0) Calm
1) Choppy
2) White crests
3) Strong waves
Visibility _______ superficial
(m)
_______ at ______ m
Temp. (°C) _______ Superficial
______ at ______ m
Mark “X” in the cell that corresponds to the abundance (# of individuals) estimated by species
Key species for tourism
No
sighting
Single
(1)
Few
Many Abundant
(2-10) (11-100)
(>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
NS = not sightings
S = single
F = few
M = many
A = abundant
Entry
time
Exit
time
Weather
Sea
Current
Visibility
(m)
Temp
(˚C)
Depth
(m)
Seriola
rivoliana
Rhyncodon
Typus
APPENDIX 3
*Example of data interpretation for each species (Tropical Eastern Pacific)
.
Den
Den
HIGH
>3.0
Den
HIGH
>3.0
Den
LOW
<3.0
Den
LOW
<3.0
%SF
%SF
HIGH
>50
%SF
LOW
<50
%SF
HIGH
>50
%SF
LOW
<50
Interpretation
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
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
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
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