1. the status of the world’s
land and marine mammals :
diversity, threat, and
knowledge
Article written by: Jan Schipper, Janice S. Chanson, Federica Chiozza, et al.
Presentation by: Carolina Fernandez

2. Vocabulary
 Taxonomy: orderly classification of plants and animals
according to their presumed natural relationships
 Estuarine(estuary):An estuary is a partly enclosed
coastal body of brackish water with one or more rivers
or streams flowing into it, and with a free connection to
the open sea.
 Invasive species- non-native species.
 Discontinuity: A distinct break in physical continuity or
sequence in time.

3. Context
This article was written in order to inform people about the most
current news concerning the mammals we coexist with. Every couple of
years an assessment of all the newest and oldest mammals is taken.
The IUCN remains committed to providing the world with the most
objective, scientifically based information on the current status of global
biodiversity. The IUCN stands for the International Union for
Conservation of Nature, formerly the World Conservation Union. They
also focus on investigating which animals are at risk of extinction and
what we as neighbors of mammals could do to prevent their extinction.
The current dataset on mammals is the product of a similar initiative to
undertake a global, comprehensive assessment of the conservation
status of all mammalian species. Prior to this assessment, the last time
all mammals were assessed globally was in 1996(4), and the majority
of those assessments are out-of-date. Overall, the article includes a
load of information, incorporating data on distribution, population
numbers and trends, habitat, life history, threats, conservation actions,
conservation status, and utilization for each individual wild mammal
species.

4. Experimental Design
Data were analyzed using a geodesic discrete global grid system
which consists of a set of regions that form a partition of the
earth’s surface, where each region has a single point contained in
the region associated with it. The maps take the form of broad
polygons that join known locations. A species’ distribution map can
consist of more than one polygon where there is an obvious
discontinuity in suitable habitat. For some range-restricted
mammals, they tried to map distribution ranges with a higher
degree of accuracy, sometimes down to the level of individual
subpopulations. The range of each species was converted to the
hexagonal grid for analysis purposes, with land and marine cells
(and their species) analyzed separately. Coastal cells were clipped
to the coastline into land and marine sections. The ranges of
‘cross-realm’ species were also clipped to the coastline into land
and marine sections, and analyzed accordingly with land and
marine cells. The maps created in each analysis have patterns for
marine species mapped on a blue scale, and patterns for land
species mapped on a brown scale. Different numerical scales are
used for land and marine, as the numbers of species differ by more
than an order of magnitude. Patterns of species richness (were
mapped by counting the number of species in each cell (or cell
section, for species with a coastal distribution).
The IUCN Species Survival Commission is an established
knowledge network of ~8,000 volunteer members working in
almost every country of the world. SSC members are deployed in
more than 120 Specialist Groups and Task Forces, with some
2,000 members being part of the mammal Specialist Group
network. Currently, there are 29 Specialist Groups with a
taxonomic focus on mammals (6), and one stand-alone Red List
Authority. For the purpose of conducting careful detailed review of
all mammal assessments, a series of 28 workshops were
conducted in 18 countries around the world (and usually in
collaboration with existing Specialist Groups).

5. Presentation of Data
Number and percentage of species affected by each of six main threat
categories. Species can be affected by more than one threat category;
being affected by a threat does not necessarily imply that the species
is globally threatened (Vulnerable, Endangered, or Critically
Endangered).
For each species, data was collected on species, genus, family,
order, taxonomic authority, English and other common names (if
any), and taxonomic notes (if needed, normally used to clarify
difficult or confusing issues). Although the IUCN Red List is not
intended to be a definitive taxonomic source, it strives to be
taxonomically coherent and consistent at all ranks.

6. The separation between
land and marine species
was purely based on their
mapped ranges, not on
the habitats that they use.
As a result, some that use
marine habitats were
mapped completely in
land. These include
freshwater and/or
estuarine species that
occupy a marine area that
is too narrow to map, for
example: Eurasian Otter
(Lutra lutra), which in
some parts of its range
forages within a few
hundred meters offshore
(36); Water Rat
(Hydromys chrysogaster),
a mainly freshwater and
brackish water species
that also uses coastal
mangroves (37).

7. Diversity
Land species have particularly high levels of species richness in the
Andes and in the Afromontane regions in Africa such as the
Albertine Rift. High species richness could also be found in Asia,
mostly in the Hengduan mountains of southwestern China. The
ranges of many large mammals have recently contracted
significantly in tropical Asia, so local diversity has decreased in
recent years. Overall the species richness in land mammals is
similar to that found for birds and amphibians which suggests that
diversity is similarly driven by energy availability and topographic
complexity.
Marine mammals concentrate in tropical and temperate coastal
platforms, as well as in offshore areas in the Tasman and
Caribbean seas, east of Japan and New Zealand and west of
Central America, and in the Southern Indian Ocean.
The range of most marine mammals is smaller than one-fifth of the
Indian ocean.

8. Extinction and New life
Twenty five percent of all mammals for which data has
been collected are threatened with extinction. The exact
threat level is unknown. Critically endangered species also
face a high probability of extinction, and for some(about 29
species) it may already be too late for salvation. Species
not classified as threatened aren’t particularly excluded
from endangerment. Many species have experienced large
range and population declines in the past.
Although mammals are among the best known organisms,
they are still being discovered. The number of recognized
species has increased by 19% since 1962 and includes 349
newly discovered species. Newly described mammals are
poorly known, which has a negative impact on their survival
rate, concerning researchers with the fact that certain
species may be extinct before even being discovered.

9. Data Analysis
These trends indicate that the overall conservation status of
mammals will likely deteriorate further in the near future,
unless appropriate actions are taken to guide the future in
another direction. On the bright side, at least 5% of
currently threatened species have stable or increasing
populations. These results paint an ugly picture of the
global status of mammals worldwide. It is estimated that
one in four species is threatened with extinction and that
the population of one in two is declining. Despite a general
decline in the status of mammals, there is a possibility of
progress through our own conservation efforts.

10. Unanswered Questions
 What kind of steps must we take in order to really
protect these mammals?
 Do we have an equal or bigger part in the extinction of
species than the natural process or climate?

11. References
Supporting Online Material (SOM) for:
The status of the world’s land and marine mammals:
diversity, threat, and knowledge. (PDF)