ENM - CC1
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Hello everybody! I am going to present to you a broad perspective on how XXXXX niche model has been used for
understanding XXXXXXXXXXXXXXX regarding the effects of climate change on biodiversity
and the distribution of species
sorry for that
well, the way that you model the distribution of species in one time and then in anothr time is very simple
XXXXXXXXXX an exercise. you just need one set of variables for your time 1 and the same set of variables for a different time
either to the future or to the past continent environmental conditions
the you give your niche model and you calibrate calibrational time period which is in XXXXX one
and the you project this model on the 2 environmental scenarios
and produce the maps , one for the present time and one for the other alternative time
then what you do is, you have here in the map say for the presence and then for the future or for the past
and in GIS you overlay these 2 maps and what you get is a comparison of the ditributions of these 2 times
so you can see and calculate the differences in the 2 areas
and say which areas correspond an expansion
XXXXXXXXXXXX XXXXXXXXXX from time 1 to time 2
so it is very simple in terms of the way it's working
let's see how this has helped us to learn nor about the responses of species from XXXXXXXXXXX XXXXXX
there are several ways in which species can respond to climatic changes
and all of them have some XXXXXXX station at dstributional XXXXXXXXXXX
so depending on genetic plasticity of species they me adapt different routes when they face climatic changes
paleophysiology of genetics phenology is important in this XXXX adaptation
in relation to the distribution of species imagine we have this hypothetical area of species in green means that environment is XXXXXXXXX
and in blue means that it's occupied in that space before climatic change
then comes the warming and cooling
and this area becomes unsuitable which is indicated here in red
but some areas might become XXXXX
we here only put a XXXXXXX to make it more interesting
well, if a species can adapt to the changes what we can expect here is that there won't be very important variations in terms of
size and the position of the geographic matrix
and actually if the species is able to disperse across this XXXXX it might expand to the new suitable areas
well, when another strategy that species have followed to deal with climatic changes id by migrating or shifting XXXXXX
there are elements from the past and elements in the present that species have moved in these climatic change heads that we are XXXXX
actually this is a study that XXXXXXXXXXX did on the abundances of North American birds
trends in the abundances of hundreds of species of American birds
and we compared the distribution of abundances before and after the eighties
and we XXXXX the document that XXXXXX have shifted basically north for most of the species
this is an indication that species are shifting distributions
we are going to look for shifts on the distribution itself
in this case when we have the situation of migration but we would expect that the original former distribution would shift
local extinction to the XXXXX here will XXX colonize in new areas
so we would see a shift in the distribution
and when adaptation or migration don't happen we would expect that species or the first population and species go extinct
of course we have the extinction documentation for the species in the past
for those who we have documentation of extinction of populations and species XXXXXX in this XXXXXXXX
this is a very XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
they work in the extinction of several populations of XXXXXXXXXXXXXXX
and they attribute these extinctions to climate change
and of course this is the most famous phase of extinction XXXXXXX XXXXX due to climate change
this is the golden talk in XXXXXXXXXXXXXXXXXXXXXXXXXXXX
so we would expect from the distribution of XXXXXXXX is that first shrinking the distribution of species
and if this trend continues we would expect a whole collapse on the event of the extinction of the species
well, we have in the exercise of modern distribution of species in the phase of climate change
we have to mix several conditions in order to make it in a XXXXXX
first as we told you yesterday and before we need to use the same set of environmental variables
in time 1 as well as in time 2
and we have to make sure that the variables we are using are informal for distribution of the species
this is the case in which we use 9 variables and XXXXX here
this is the present and this is the future
we are using XXXXXXXXX of environmental variables
we may know since models
so it's very important that you pay attention to the information that you are using
another important aspect here is that the species you are modelling in the present for example
have to be in a very XXXXXXXXXXXX with the environment
This means that species is XXXXX that field of the potential distribution XXXXXXXX actual distribution
actually feeling of XXXXXXXXXXXXXXXXXX
otherwise if you have a species with very narrow distribution with a broad niche distribution
and you project that into the future you don't know if those changes are going to be well known for the species or not
so next thing is that you have to produce reliable models for the present
in order to be able to project into different times
if you are not able to do models on the present conditions it makes no sense to project the models to XXXXXXXX because
if the modelling present is wrong it's going to be even worse in different scenarios
but what you conjugate from that analysis is just XXXXXXXX
well there is a key assumption here
when we work with XXXXX models in time, niches are basically static
that's XXXXXXXXXXX assumption XXXXXXXXXX
and in relatively fast processes of climatic change this is a safe assumption for many species
basically for species with relatively slow XXXXXX rates
but think of this, the ecological niche modelling approach is a static method
we are like looking at one place or time and we are trying to model climatic processes in this case
so that's an increasing limitation of this approach for this problem
never the less it's probably the most popular approach for addressing climate change in such XXXXX