- [Moderator] Aaron weed's presentation.
He a program manager of the Northeast Temperate Inventory
and Monitoring Program with the National Park Service.
He will be presenting today about community trends
in forest bird abundance within
northeastern national parks - [Aaron] Yeah thanks so much.
Thanks for the introduction and everybody
for sticking around today and joining us today.
So I'm gonna, as a title talks about, mentions.
I wanna talk about birds and I'm not gonna spend a ton
of time talking about sort of the nature of our program
because Kate Miller in the plenary yesterday
did an excellent job of giving an overview
of the monitoring that we do and why we do it
and particularly focused a lot
on summarizing some of the trends in forest health
which are obviously directly relevant
to the discussion I'm gonna have today.
So, today I'm gonna talk
about a program that really is a compliment
in many ways to the forest health monitoring
and I also sort of provide sort of a couple
of disclaimers here that have a lot
of information to talk about
and so it would be hard to maybe go
into super amount of detail
but I'll be happy to answer as many questions as possible
but the goal here is just to provide a kind
of an overview at the community level.
I'm actually gonna shut
off my video in case that causes any interruptions too.
Okay,
so,
as Kate mentioned yesterday in the plenary, very nicely
our parks in the northeast are pretty unique
in terms of forest structure and because
of the protection that they have through the park service.
However, we do have some key forest health issues such
as invasive plants and pests, deer overabundance and
lacking regeneration in a few parks
and so in addition to understanding forest monitoring
and sort of those,
effects in the vegetation community, we have
another program looking
at landbird breeding birds within these forests
so that we can get another dimension
of what is going on in these forests
and then so ultimately
that we can begin connecting the dots
so to speak of how some of these trends
and forest health may be influencing other levels
of organizations such as birds
and so our landbird monitoring program
which has been presented a little bit
in the past few years
in this conference was
initiated back in
around 2005 or 2006, with the help
of Steve Faccio at Vermont Center of Ecostudies
and so Steve, this is before my time
but Steve helped develop the protocol
within these parks that are depicted in the screen here
but what I wanna just give a basic update and sort
of a background of what that protocol is,
and then I'm gonna sort of go right
into some of the trend results.
So in general, the objectives of the program are
to evaluate trends and abundance of species breeding
in our park, forest and grasslands.
Today, I'm gonna specifically focus
on the forest level monitoring,
but we do have a few routes in a couple
of parks that are specific to grasslands
some secondary objectives of this program.
We're also sort of trying to evaluate what we're finding
in the forest and how that's influencing the birds as well
and I'll talk a little bit about how we evaluated that
in our analysis,
and our sampling design is a pretty common point count.
It's a 10 minute point count variable radius where
we have a number of permanent sites across our parks.
The number of the sites that we have in each
of our parks is proportional to the forest area.
All of our sites are separated by, roughly 250 meters
and across the entire network of parks, we have just
under 250 permanent point count stations that have
been monitored annually since roughly 2006 or 2007,
depending on the park
and for the most part these sites are,
we try to get them visited at least once a year
and some of them actually have repeat visits
and at each of the points, of course observers are recording
the number of birds that they've heard
or that they have seen
within approximate distance bans from them, as well
as recording when during the 10 point count
they've encountered the individuals
and that's important in sort of assessing
the detection component when estimating abundance
which I'll talk about in just a little bit.
Other thing that's important to know
about this program is that that each
of our longterm bird monitoring points is co-located
with the forest monitoring plot
which we'll take advantage of in the coming analysis
and the last point that I'll make is
that this is a volunteer based data collection program
and so of the 70 or so names that you've see here
these are all folks that have contributed in some fashion
over the last 15 or so years to collecting bird data for us
and without this great effort and dedication
in many ways of these folks, we wouldn't be able to do this.
I also, a major sort of shout out to Steve Faccio
who from the beginning has pulled this program together
and helped sort of maintain it at least
for the first 13 to 14 years of it
and so one thing that I do wanna mention is
that this has been a really ingrained engagement piece
for our parks.
We have professional birders perhaps, some of them
you might know their names that are listed here
but these sort of very
in terms of being trained
to more or less professional birders
that are within our parks
and so I just wanted to say
thank you for all of that commitment
and we encourage you guys to keep coming back
because this has really been a real fun program for us.
Okay so now turning to certain sort
of the specific analysis questions that we had
we're basically looking, this program is as a part
of the inventory monitoring program is we're sort of
as any of these programs are
we're required to do trend analysis
and so not only so
that we can understand what's going on with these resources
but those provide us obviously scientific evidence to know
whether or not we're meeting our protocol objectives
and so that's really sort of the context of this analysis.
We looked at, what are the trends in forest bird richness
and abundance at the park and network scale
and then looking at the effects
of local forest structure on bird abundance and
on this paper, we had a number
of really great colleagues from Michigan State University.
I worked with Andy Finley there,
one of his PhD students approached me
about developing this model so
that he could to analyze these data.
So Kate Miller and myself
and these folks are on this collaborative project together
and I should mention
that this is the lion's share of Jeff's sort of work
and these guys are the real math geniuses
behind a lot of this.
So I don't have a lot of time to go
into specifics about sort of the details of the model
am happy to address questions if people have those
but for those folks that are familiar with working
with bird point count data or any wildlife datas such
as the prior presentation,
these can be challenging data to analyze, and
they sometimes take challenging models to actually fit
but because we were interested in sort of looking
at the effects of estimating trends in bird abundance
and looking at different scales, we brought in sort
of a multi-level or a hierarchical model that looks
that model is essentially the species
as a community and also at different regions.
One of the things that was probably
I hope apparent in Kate's talk yesterday is
that our parks are very different,
in terms of forest structure
and so this model provides us abilities to evaluate that.
The other thing that it does is it's modeling it
as a community
and the benefit of that is that it's sharing information
across species in terms of their detection probability
and for us, that allows us to get better inference
on species that are rarely detected
or parks that are sparsely sampled
and so if you look at sort of this table, you can see
that we have a couple of parks, like Weir Farm
which is near the New York border
in Connecticut only has five sites in it.
Saint-Gaudens in Cornish New Hampshire
only around roughly eight.
So this model sort of brings in sort
of an allows us to provide that estimation
across those different scales and areas and species.
So in addition to understanding and estimating the abundance
of species and the trend in those species
this also does have this model does account
for imperfect detection, sort of following kind
of a classic removal monitoring protocol using
the time period of first observation.
So that's where sort of
the countdown information comes into the point count.
We also evaluated, within the detection covariates looking
at time since sunrise
of the counts and the day of year
some of this might be all very common to many
of you may, maybe not, again, I'm happy to,
answer more questions if there are interests.
Another noble aspect of this model is
that in addition to sort of the detection components
we've actually looked at the effects
of local forest structure on forest bird abundance
at the site level, we use three covariates in the model.
One of them was percent forest cover
from a national land cover data base
of within one kilometer of the site.
We also were able to use Kate's the long-term
monitoring plots to estimate the total regeneration density
at the site and also the basal area
and unfortunately, I don't have the time to go
in sort of all
of the details of those local forest structure covariates
but if anybody has any specific questions
I have a slide that I can kind of review over
if folks are interested in that, but I'm really gonna stick
to some of the big patterns
and trends that we're seeing across the network.
Okay so just to kind of walk through those trends well
in the results right now.
So just to give you a sense
of these are the number of observed species that we've seen
across the parks over time, across all of the years.
So across the network, we're seeing, oops
we were seeing a hundred
and this model is estimating abundance
of 106 species with Saratoga, Stillwater New York
and Acadia National Park in Bar Harbor Maine bringing
in roughly around 70 species
and then fewer species in some of our smaller sample parks.
What's important to note here is that these aren't all
of the bird species that are using these parks.
These are the ones that are being detected
and primarily within 50 meters of the observer
and thought to be breeding within the parks
during sort of that specific pre peak breeding period
and so to talk a little bit
about some of the trend estimates
so I just wanna walk you through this figure.
So basically, as he said, this is a hierarchical model.
So it allows us to estimate what's going on
at the network level all the way
down to the park and species level
and so what we're seeing here, basically these numbers
are showing you the quantitative it's the slope estimate
of the changes in abundance of all of the birds over time
and again, does the top is at the network level or NETN
which this white bar basically shows
that the population abundance across all species is stable
but that when we look at the park scale, we have
we see geographical variation
in the directions of the trends.
We have three parks that show us statistical increases
and those were in Roosevelt Vanderbilt
and the Hudson River Valley
and New York Saratoga National Store Park Battlefield
in Stillwater New York
and then Weir Farm, which is in Connecticut
and we have three parks that are showing statistically
significant declines in overall forest bird abundance
and that's in
Marsh-Billings-Rockefeller National Historic Park
in Woodstock Vermont, Acadia national park in Maine
and then Morristown in New Jersey
and then we have two parks
in the middle of there that are basically stable.
I won't have time to go into all of the
sort of the species specific details
but what we're seeing just in general is
that when we are seeing statistically significant declines
in a park, that's actually happening
across the entire community, which is obviously
not great news for some of these parks
and the last point that I'll mention from this analysis is
that the trends in richness are largely mirroring those
in abundance as well.
Another way to look at this data is
if we characterize the trends
of the species within these different guilds
and so what's basically depicted here
in the Y-axis are the guilds and their names
and so these are these functionally similar species
that are grouped by where they forage,
how they eat and where they nest and their origin
whether they're exotic or not
and then what's depicted sort of in the
with the color is, again
is similar to the last slide where the red boxes
are indicating negative or trends in abundance over time
and overall abundance with the guild where
blue is significant increases, excuse me
and the significance of the trend
has being different from zero as denoted by the asterisks.
So what's pretty apparent here is that
we're seeing significant declines where
or changes they're happening
across the entire bird community
which basically I think means is that the entire
the forest condition is having a fairly consistent effect
across the entire bird community.
Even despite seeing the lack of exotic species in some
of these parks where we're seeing declines, there
we're seeing overall more or less a consistent decline
in these forest specialist species
and some of these parks to the left
whereas we're seeing increases over to the right
but what I think is particularly
depressing and I guess I would say is
if we look at these data
in another way, and so a common way to sort of
to summarize
these species data is to basically
calculate what's called a bird community index
and basically what that does is
that a higher bird community index indicates a species
excuse me, an area forest, a site that is represented
by a higher, a
number of special forest bird specialists
whereas a lower bird community index rating
is a bird community
that's has a greater proportion of generalist species
and so if We look at this chart,
basically what we're finding is
that the average site level of BCI or bird community index
again, better higher, more high integrity communities
are over to the right than to the left.
If we look at, if we regress that against
the average trend estimate direction,
we basically find that the abundance
of our specialists bird communities, or are
in our parks that are more high integral are
actually declining faster,
which is obviously not what we wanna see.
I think it's suggests, and it's suggesting
that we're obviously seeing our increases in a lot
of these increases are probably happening within some
of these more general species or these forest
that aren't having as high
ecological integrity, excuse me
and so for the last few minutes, I kinda of wanted to turn
to something that's a little bit sort of closer to home
in Vermont here for me and compare some of our results
to the Vermont bird monitoring program
which this publication, many of you might be familiar
with that Steve and his colleagues put
out a couple of years ago
and so what I basically did is I've sort of pulled it.
I'm just wanted to, this is some level of validating some
of the results of our trend analysis to see
whether or not what the consistency is
within the Vermont forest bird monitoring program
which is in the first row here compared
to the specific monitoring that we're doing
at Marsh-Billings in Woodstock.
A couple of caveats I should mention upfront here
is obviously the periods
of observation of the trends are different
not exactly the same, but they do overlap
and the other thing to mention here to note is
that Marsh-Billings is actually one
of the sites within this forest
for a monitoring protocol and so, or program.
So there could be some expectation for similarities as well
but the point is, is that Marsh-Billings,
we have 25 sites that we're monitoring there
and then there's many hundreds of sites across the state
and I just wanted to do a broad,
comparison of that.
So all of the species of the 34 species that Steve
and his colleagues were looking at in that analysis
they basically analyze across the state
of the forest birds and said
that there is 13 of those or 38% of those 34 species
are showing significant statistically significant declines.
Whereas 14
of them are showing statistically significant increases
and then 38% of them are showing no trend.
If we compare that to what we're looking
at in Marsh-Billings, we were only able to look
at 32 species that are comparable between both
of the datasets that were detected in the park.
Basically we're finding
that a lot of the species, there's no trend in abundance
and part of this is because the detection history
of them is quite low, but what's kind of
I think is kind of staggering is that over half of
or nearly half of the species
we're finding statistically significant declines
in abundance
and there's only one species that we're
actually seeing an increase
but what I think is also a little bit more staggering
from my point of view is that 90%
of the forest birds that we monitor
in Marsh-Billings are showing they might not
be statistically significant declines, but over time
their relative abundance are declining.
So just sort of to kind of wrap
up this kind of Vermont centric evaluation
what we're seeing is,
is comparisons to what's going on
in our bird monitoring to the statewide is
that we see are seeing similar declines
in Blackburnian Warbler compared to
the state Common Yellowthroat, Eastern Wood-Peewee
and Rose-breasted Grosbeak excuse me
that's consistent
between the two programs and both programs seem to be
at least last I looked to seem to be showing is
statistically significant increases in Pileated Woodpecker.
What I find to be the most challenging
or maybe even depressing thing
or what we're trying to understand here more
is why that there's many species that have been in the
for Vermont forest
for a monitoring protocol that seemed to be
at least stable or increasing
across the state are actually declining in Marsh-Billings
and these are some of our very common species such
as Ovenbird, and Red-eyed Vireo.
We have Wood Thrush, Yellow-bellied Sapsucker,
Hairy woodpecker,
Black-throated Green Warbler, Brown creeper and
American Robin.
So
I'll just conclude,
apologies for this is actually not great news
but this is the way that it is
but I do wanna mention that,
the long-term commitment of our partners
and volunteer support has made this work possible.
I sort of look at sort of our data and our analysis
as a working hypothesis so this is what our monitoring is
and I think it's really valuable that we're able
to compare this to other programs
and I wanna continue doing that
but we can't do this without the work of all of those folks
and so I want to thank them, individually
for their contributions,
in general
while we're seeing that our network level trends are stable
we have a couple
of parks where we're seeing some really,
important declines of these forest specialist species
which is obviously concerning this isn't a new pattern
but it is something that we haven't really
been able to share with our parks before
and so this is something that we're gonna be working
further to understand why are these patterns happening?
What are the underlying mechanisms?
And to kind of, to dovetail off a little bit
of Kate's points in the plenary is
our program is really a position
to trying to understand these changes
and make practical recommendations
to these parks for management
and so we're looking to dig deeper
into some of the mechanisms and understanding
and also the species specific level,
natural history requirements, so that there
perhaps there are ways that they're promoting regeneration
promoting a better forest health
that we can promote actions, excuse me, that will lead
to better forest health that will hopefully
have some concurrent benefits to these birds
but we'll continue doing this work and continue monitoring
and engaging you folks on all of this in our parks.
So that, I just wanna say, thanks for listening.
I'm sorry.
If I went over a little bit
there is our contact information.
If you have any questions now I'm happy to take them.
Thanks.
- [Moderator] Here we go from Pete Kirby Miller
the decline your document is concerning
what research might be necessary to develop understanding
for adaptive management strategies to combat those declines.
- I knew you gonna have to read that one is what research
might be needed necessary to develop.
Well, yeah, so that's a really good question.
I think that there are probably others listening that are
probably better poised to answer that than I am.
We have, what's one of the interesting sort
of experiments that's happening in our network parks is
that Marsh-Billings, which some of you may know
has actually been doing silver culture for years.
So it's actually one
of those parks where we're able to actively manipulate
and have actively manipulated the over story
and some respects the understory.
So I think that we can utilize some of that information to
be assessing inference of how,
time since disturbance or changes in certain features
of the canopy are influencing those forest birds
but I also think that there is an opportunity here
and that looking,
using the forest bird monitoring program and other areas
across new England, that we can correlate
this information to get,
a better understanding of how manipulations
in the forest are influencing forest birds.
It can't be understated that,
Hubbard Brook has a real, roughly 50 years
of data when we are very similar communities
and so I think that it's our,
the opportunity is to combine some
of these data sets to be able to ask some
of those questions, but we do have some very
specific species specific management
at Marsh-Billings in particular that Kyle Jones
who was the resource manager there for years to set
up and sort of, looking at,
the responses for example
a Chestnut-sided warbler to different types of
treatments.
So it's a really good question that
I hope that we begin to answer and essentially
be able to develop these adaptive management frameworks
to address.
Thanks for the question.