Adaptive grazing management to optimize cattle performance and rangeland bird diversity and abundance

David Augustine Author

10/14/2016 Added

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Part of the 2016 Fall Seminar Series in the School of Natural Resources

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[00:00:00.938]All right, well, thanks EJ for inviting me here.
[00:00:02.277]Thanks for the opportunity to meet many of you today,
[00:00:05.792]and hear about the work happening here at UNL.
[00:00:08.500]I'm gonna take the next 45 minutes
[00:00:10.324]to talk to you about work that I've been doing
[00:00:11.859]mostly in eastern Colorado over the past decade,
[00:00:15.396]working for the Rangeland Resources Unit within the USDA.
[00:00:20.067]I think the reason I'm so interested about rangelands,
[00:00:22.275]particularly here in the United States
[00:00:24.727]and in the Great Plains is because
[00:00:26.982]it's this huge part of our country,
[00:00:28.722]in terms of land mass, that's being used
[00:00:30.727]to both produce food for people,
[00:00:33.638]through livestock agriculture,
[00:00:36.604]but it's doing this in a landscape
[00:00:38.957]that still retains the vast majority
[00:00:40.764]of the biodiversity that existed in them
[00:00:43.703]prior to European settlement.
[00:00:46.730]The subtitle I have up here,
[00:00:47.834]trade-offs and synergies in managing
[00:00:49.110]for beef and biodiversity in the Great Plains,
[00:00:51.328]I think captures the work I've been doing,
[00:00:53.848]trying to think about how these landscapes
[00:00:56.447]both produce food for us and conserve biodiversity.
[00:01:01.369]Before I get started, I should also acknowledge
[00:01:04.186]a number of cooperators, Justin Derner and Lauren Forensky
[00:01:06.537]are with USDA-ARS, working in the same
[00:01:09.742]research unit as myself,
[00:01:12.444]and Susan Skagen is an avian ecologist with USGS,
[00:01:15.473]Maria Fernandez-Gimenez and Hailey Wilmer
[00:01:17.520]are with the Range Department at Colorado State University,
[00:01:21.110]and they've all contributed substantially
[00:01:22.912]to the work I'll present today.
[00:01:26.412]So, for a road map, what I'll talk about here,
[00:01:28.257]first of all, why do we care about
[00:01:29.289]heterogeneity in rangelands?
[00:01:32.915]I'll try to answer that question very briefly,
[00:01:34.912]and then talk about management paradigms
[00:01:37.103]in Great Plains rangelands,
[00:01:39.588]and then the bulk of the talk,
[00:01:41.043]I will focus on quantifying trade-offs
[00:01:42.688]between management for biodiversity
[00:01:44.236]versus livestock production.
[00:01:48.149]Over the past ten years, I'd say,
[00:01:49.655]the first five years of that I focused
[00:01:52.252]mainly on livestock-fire-prairie dog interactions.
[00:01:54.671]A lot of that work's been published,
[00:01:56.526]but I wanted to present it here
[00:01:58.593]to understand how it's led in
[00:01:59.880]to the work that we're doing today,
[00:02:01.891]and then I'll talk about a more recently developed
[00:02:04.480]adaptive grazing management experiment
[00:02:07.066]where we're looking at managing
[00:02:08.338]for rangeland heterogeneity.
[00:02:12.354]So, why heterogeneity?
[00:02:14.258]As we go from all kinds of different ecosystems,
[00:02:17.907]from alpine zone, to forest,
[00:02:19.100]to savannas, to grasslands,
[00:02:22.606]it's widely recognized by ecologists
[00:02:24.596]that heterogeneity, both in the landform
[00:02:29.078]and in vegetation structure and composition
[00:02:32.190]is the basis for conservation of biodiversity
[00:02:34.138]of broad spacial scales.
[00:02:36.022]I think one paper that really,
[00:02:39.008]if I had to pick one paper that really
[00:02:40.563]demonstrates this clearly,
[00:02:41.862]it's a nice reviewed paper by Tews, et al,
[00:02:44.286]published in 2004 in the Journal of Biogeography,
[00:02:47.896]and what they showed is, based on a worldwide review,
[00:02:50.729]85% of published studies across
[00:02:52.639]a wide range of taxa and a wide range of ecosystems,
[00:02:55.679]this is focusing mainly on animal taxa,
[00:02:57.811]arthropods and mammals and birds,
[00:03:02.079]they found a positive correlation between
[00:03:03.745]biodiversity and habitat heterogeneity,
[00:03:05.873]when we're looking at habitat heterogeneity
[00:03:07.369]as variability in the three-dimensional structure
[00:03:10.707]of plant communities.
[00:03:13.395]The thing about applying this to rangelands,
[00:03:16.173]this is a fairly widely cited paper
[00:03:18.814]that was published by Sam Fuhlendorf and David Engle
[00:03:21.298]about 15 years ago, where they said
[00:03:23.554]we really need to be thinking about
[00:03:24.789]how we can be restoring heterogeneity
[00:03:26.813]in our rangelands here in the Unites States.
[00:03:29.984]In thinking about ecosystem management
[00:03:31.958]or rangeland management based on
[00:03:33.333]evolutionary grazing patterns,
[00:03:35.881]and they made a very simple proposal
[00:03:37.882]that I think is really shaking things up
[00:03:40.284]in rangeland management since this publication.
[00:03:43.420]They propose a paradigm that enhances heterogeneity
[00:03:46.412]instead of homogeneity to promote biological diversity
[00:03:48.989]and wildlife habitat on rangelands grazed by livestock.
[00:03:53.401]How exactly you go about managing
[00:03:56.332]for heterogeneity and homogeneity, however,
[00:03:58.046]is not at all straightforward,
[00:04:01.039]and so a lot of the work that I've been trying to do
[00:04:03.235]over the past ten years is address,
[00:04:05.075]how do we actually manage for heterogeneity
[00:04:08.000]in the western part of the Great Plains,
[00:04:10.135]and what are the costs of doing that?
[00:04:14.294]So, what I would call traditional
[00:04:15.942]homogeneity-based rangeland management
[00:04:18.573]is primarily focused on increased animal production
[00:04:22.540]through homogeneous utilization of vegetation.
[00:04:24.869]So, anybody that was brought up in
[00:04:26.249]a traditional range science department or background,
[00:04:30.190]this is what we've been taught.
[00:04:31.505]We need to figure out how to get our animals
[00:04:33.301]distributed evenly across the landscape,
[00:04:36.347]and make a homogeneous and fairly even
[00:04:38.123]utilization of available forage.
[00:04:40.390]In the part of the world where I work,
[00:04:41.843]in eastern Colorado, this is a stocking rate guide
[00:04:43.768]that was published in 1969 by Bement,
[00:04:47.675]and what he's showing here is based on
[00:04:50.409]about 20 years of grazing trials in eastern Colorado.
[00:04:53.974]He equates ungrazed herbage, varying from low to high
[00:04:57.880]at the end of the grazing season
[00:04:59.848]with your stocking rate, again going from high to low.
[00:05:03.371]If we graph gains per head,
[00:05:05.630]so daily gain per individual animal,
[00:05:08.177]as a function of this X-axis,
[00:05:09.839]it goes up and then levels off,
[00:05:12.619]and if we calculate gains per hectare,
[00:05:15.333]it has a peak here, and then it declines.
[00:05:17.067]This intersection of these two curves
[00:05:18.658]is our optimal stocking rate if
[00:05:20.314]we want to maximize animal production.
[00:05:24.776]This is old, it was published in 1969,
[00:05:27.527]and yet this graphic here still guides
[00:05:30.469]most of the management of the national grasslands
[00:05:32.449]in the western Great Plains today.
[00:05:35.195]National grasslands in Colorado,
[00:05:36.904]this intersection point occurs at
[00:05:38.471]300 pounds per acre, approximately.
[00:05:41.169]That's when the cattle go home from
[00:05:42.454]the national grasslands.
[00:05:43.701]If they get below 300 pounds per acre,
[00:05:45.450]cattle come off our national grasslands.
[00:05:47.240]So I would say yes, this is an old publication,
[00:05:50.714]but it's still guiding our management today.
[00:05:54.659]Second thing we do a lot of is
[00:05:56.143]use fencing and water to achieve
[00:05:57.419]proper livestock distribution.
[00:05:59.503]It's a huge part of what NRCS does
[00:06:01.729]in the western Great Plains.
[00:06:03.149]The 528 prescribed grazing program,
[00:06:06.508]a lot of funding and cost share
[00:06:08.032]from the Farm Bill being spent on fencing and water
[00:06:11.255]to achieve improved livestock distribution.
[00:06:15.310]In terms of fire management, again,
[00:06:17.240]focused on even utilization of landscapes,
[00:06:19.513]on the left had side we have most of the Great Plains,
[00:06:21.984]most of the mixed and short grass steppe
[00:06:24.165]in the western Great Plains,
[00:06:25.737]fires are widely suppressed
[00:06:28.430]and rarely used to manage rangeland.
[00:06:30.699]It's changing here in Nebraska,
[00:06:32.755]I understand hearing from Jack
[00:06:34.342]that they were talking about fire management
[00:06:36.479]at the football game, so that is a big change
[00:06:38.941]from a few years ago.
[00:06:41.766]Southern tall grass prairie is
[00:06:42.844]the only place I know of in the Great Plains
[00:06:44.705]where fire is frequently used,
[00:06:47.566]and there you're burning essentially the whole landscape.
[00:06:49.990]Burns are used to encourage uniform utilization
[00:06:53.598]of the landscape by the livestock.
[00:06:56.566]This is a photograph from the foothills in Kansas.
[00:07:00.852]You can see that under this management
[00:07:02.887]of annual complete burning with
[00:07:05.013]intensive early stocking with yearlings,
[00:07:08.078]you get this nice, smooth, homogeneous landscape.
[00:07:11.012]Here, even with all the topographic heterogeneity,
[00:07:13.999]the entire landscape is dominated
[00:07:15.520]by a single grass species, big bluestem.
[00:07:19.026]My part of the world, eastern Colorado,
[00:07:21.183]fire suppression, moderate stocking rates,
[00:07:23.858]even cattle distribution, you get a landscape
[00:07:26.208]with a lot of subtle topographic heterogeneity,
[00:07:29.289]but dominated by just two or three grass species.
[00:07:34.228]So, Bement's stocking rate guide was published in 1969.
[00:07:38.412]About 25 years after that, Fritz Knopf from the USGS
[00:07:41.976]published a book chapter and a series of articles,
[00:07:44.976]one of which contains graphics shown on the right.
[00:07:48.589]Again, these two graphics shown here
[00:07:52.061]have had a huge influence on people's thinking
[00:07:54.011]about management in the Great Plains.
[00:07:55.698]This graphic on the right has been shown
[00:07:57.029]at almost every conference I've been to
[00:07:58.855]talking about grassland birds in the past five years,
[00:08:01.933]even though it's a fairly old publication.
[00:08:05.802]What Fritz proposed with this graphic here
[00:08:08.640]is that variation of vegetation structure,
[00:08:12.145]going from barren to a mixed tall grass shrub mosaic
[00:08:16.758]is needed to sustain habitat for the full suite
[00:08:18.953]of grassland bird species.
[00:08:20.266]Each grassland bird species can be arrayed
[00:08:22.161]in terms of its breeding habitat requirements
[00:08:24.574]along this gradient, and he also,
[00:08:27.096]in this diagram, equated grazing pressure
[00:08:29.840]from none to excessive across here.
[00:08:32.440]So we have a conflict.
[00:08:33.623]We have traditional range management
[00:08:35.210]saying we need to be managing for
[00:08:36.559]the single point in the middle.
[00:08:38.258]If we manage for the single point in the middle,
[00:08:39.861]we're losing habitats for bird species
[00:08:43.141]on either end of the gradient.
[00:08:45.951]And it's also been pointed out that
[00:08:47.968]species on both sides of that gradient
[00:08:49.561]have been declining for a long time.
[00:08:52.014]The two species on the left here,
[00:08:53.275]mountain plover and McCown's longspur
[00:08:54.862]are associated with that short end of the gradient.
[00:08:57.713]This is breeding bird survey data
[00:08:59.207]showing that they've been declining steadily
[00:09:01.679]for the past four decades.
[00:09:04.075]On the right side, we've got lark bunting
[00:09:05.332]and grasshopper sparrows, again,
[00:09:07.984]both species that have been declining steadily
[00:09:10.258]for four decades.
[00:09:12.274]You've got all four of these species
[00:09:13.993]breeding in the western part of Nebraska, as well.
[00:09:17.605]So, what's going on here?
[00:09:19.954]It's been called an unfolding conservation crisis.
[00:09:23.195]It's been pointed out that grassland birds in general
[00:09:25.396]are the most rapidly declining guild
[00:09:27.679]of birds in North America.
[00:09:30.880]There's been this call for understanding
[00:09:32.236]ecological processes in different regions
[00:09:34.548]to understand these declines.
[00:09:39.200]I also want to talk about habitat loss,
[00:09:42.124]loss of rangelands in the western Great Plains.
[00:09:44.645]This is the National Land Cover Database from 2011,
[00:09:48.417]and I've colored this to make it really apparent
[00:09:52.585]where the grasslands are located,
[00:09:55.876]relative to the crop lands, let's see here.
[00:10:00.935]This yellow here is my estimate of the outline
[00:10:03.733]of the Great Plains, and you can see
[00:10:05.913]the northeastern Great Plains, yes,
[00:10:07.711]were largely converted to croplands,
[00:10:09.506]and most of it, most of the declines
[00:10:13.033]in biodiversity in that region
[00:10:14.438]are related to just complete habitat loss.
[00:10:17.707]But I want to point out also that
[00:10:19.462]throughout the Great Plains,
[00:10:20.424]there are some huge chunks of
[00:10:21.471]remaining grasslands, mostly privately owned,
[00:10:24.312]being managed for livestock production.
[00:10:26.347]Here in the northwestern part,
[00:10:27.871]the mixed grass prairie, the sand hills of Nebraska,
[00:10:31.179]and then also a huge chunk of land down here
[00:10:33.395]that I refer to as the short grass steppe
[00:10:34.821]because it's warm and arid,
[00:10:37.431]and then the tall grass prairies in
[00:10:39.583]the Flint Hills of Kansas and Oklahoma.
[00:10:42.083]So there are still big parts of these landscapes
[00:10:44.546]that are in grassland, haven't been converted
[00:10:46.874]in the past 40 years, and yet we're seeing
[00:10:48.565]steady declines in many grassland bird species.
[00:10:53.037]So there's been a call to think about,
[00:10:54.188]how did the disturbance regimes affect these habitats?
[00:10:57.798]In the tall grass prairie, a lot of emphasis
[00:11:00.064]has been placed on the interaction
[00:11:01.340]between large grazers and fire.
[00:11:04.408]On my side of the Great Plains, the dry side of it,
[00:11:07.315]I think that drought and prairie dogs
[00:11:08.870]are also two important disturbances
[00:11:10.421]that we need to think about in terms of
[00:11:13.157]how they influence variation and heterogeneity
[00:11:15.107]in these landscapes.
[00:11:16.730]So it's the interaction between these four things
[00:11:18.467]that I've been particularly interested in,
[00:11:20.852]and I've been working mostly in northeastern Colorado.
[00:11:24.308]The research group that I work for
[00:11:26.275]owns the Central Plains Experimental Range,
[00:11:28.319]which is a 16,000 acre experimental ranch
[00:11:32.106]in Weld County, Colorado, and that's located
[00:11:34.060]right next to the Pawnee National Grassland,
[00:11:36.314]so the work I'll show you is
[00:11:38.264]conducted mostly on our experimental ranch,
[00:11:40.259]and also on the adjacent national grassland.
[00:11:44.132]One species we've been really interested in
[00:11:45.723]is the mountain plover, this was proposed
[00:11:47.383]for listing under endangered species act in the late '80s
[00:11:50.640]and went through a whole series of litigation
[00:11:52.531]about that listing in the early 2000s,
[00:11:55.047]so there's a lot of politics surrounding this species.
[00:11:58.578]It requires very short vegetation structure
[00:12:01.002]and a substantial amount of bare ground for nesting
[00:12:03.133]because it uses bare ground as camouflage,
[00:12:06.279]and this is, if you can see in this red circle,
[00:12:09.188]that's a mountain plover sitting on its nest.
[00:12:13.073]It's a ground nesting bird,
[00:12:14.543]and when they pull the head down
[00:12:15.677]and you can't see that beak there,
[00:12:17.005]it pretty much disappears, it's amazing to watch
[00:12:19.288]them out foraging on these kinds of habitats.
[00:12:21.299]When they're facing you, you can see the white breast.
[00:12:22.914]When they turn around with their back to you,
[00:12:24.315]they suddenly vanish.
[00:12:27.983]So, why is this species declining?
[00:12:30.373]If we think about this gradient here from right to left,
[00:12:34.038]when I first started working on the species,
[00:12:35.666]it seemed pretty straightforward here.
[00:12:37.047]All we needed to do was overgraze
[00:12:38.378]a bunch of rangelands and we'll be fine.
[00:12:42.257]However, a number of ecologists in the '90s
[00:12:45.294]also pointed out that when the species is in migration,
[00:12:49.730]they tend to make a lot of use of
[00:12:51.274]the few wildfires that have occurred
[00:12:53.630]in the western Great Plains.
[00:12:55.561]And then there's a population of this bird in Montana,
[00:12:57.914]Phillips County, Montana that has been
[00:12:59.490]under study for about 20 years,
[00:13:01.091]and that population breeds exclusively
[00:13:02.622]on prairie dog colonies.
[00:13:05.518]So there was some, a lot of discussion and controversy.
[00:13:08.952]Is it that we have suppressed disturbances
[00:13:11.051]like fire and prairie dogs throughout
[00:13:13.310]most of the range of this species,
[00:13:14.635]or do we just need more cattle grazing?
[00:13:17.750]A lot of the ranchers that I work with
[00:13:19.481]that graze on the Pawnee, when this species
[00:13:22.727]came up for listing, came to us and said, hey,
[00:13:24.791]we can produce habitat for this species,
[00:13:26.668]just let us graze heavy,
[00:13:27.805]and we'll take care of things for you.
[00:13:31.667]Other folks, NGOs associated with the grasslands
[00:13:34.886]said wait a minute, let's think about how
[00:13:36.188]we can use these kinds of disturbances.
[00:13:38.352]So we started a study about 10 years ago
[00:13:41.507]that compared these four treatments.
[00:13:43.618]We had very heavy spring cattle grazing
[00:13:45.379]with supplemental feed, this was double
[00:13:47.118]the recommended stocking rate from March until May,
[00:13:50.462]so in the spring when the birds are migrating in.
[00:13:52.985]We had a second treatment that was
[00:13:54.060]double the recommended stocking rate
[00:13:55.853]from May until October, so very heavy summer cattle grazing.
[00:14:00.518]With the spring, we also have to provide supplement,
[00:14:02.742]because there's not enough protein in the food at that time.
[00:14:05.589]And then we also compared this to prescribed burns.
[00:14:07.878]We did both patch burning and larger scale burns,
[00:14:10.388]patch burning in an experimental context on our range,
[00:14:14.057]and then the large scale burns being conducted
[00:14:16.190]by the Forest Service, and we also went out
[00:14:18.518]and found allotments that had
[00:14:20.364]prairie dog colonies in them and studied those,
[00:14:22.776]and compared all of this to past years
[00:14:24.420]managed with moderate summer cattle grazing.
[00:14:29.229]Very briefly, I don't want to go
[00:14:30.557]too far into the details of these two figures,
[00:14:32.634]but this top graph shows cover and bare soil
[00:14:37.121]under the different treatments,
[00:14:38.310]and the bottom graph shows vegetation height.
[00:14:41.340]We quantified this over a four year period,
[00:14:44.359]and let's see, I lost my mouse.
[00:14:45.927]Over a four year period,
[00:14:46.916]this is the average of the four years.
[00:14:48.819]What you see, these blue colors here,
[00:14:51.502]with very heavy cattle grazing,
[00:14:54.867]either in the spring or in the summer,
[00:14:56.630]we were able to slightly increase
[00:14:58.751]the amount of bare soil exposure on these pastures,
[00:15:01.763]and we were able to slightly decrease
[00:15:04.133]the vegetation height, but the problem was
[00:15:06.547]that in wet years, cattle could not
[00:15:09.200]keep up with the vegetation.
[00:15:12.880]As a result, burns and prairie dog colonies,
[00:15:14.987]shown in green and yellow, produced much higher levels
[00:15:17.559]of bare soil and much shorter vegetation, on average,
[00:15:21.389]and over this four year period,
[00:15:22.973]I and a crew of technicians went out
[00:15:24.780]and surveyed all of these treatments very intensively
[00:15:28.094]for mountain plover individuals
[00:15:30.251]and mountain plover nest sites.
[00:15:32.484]About 90% of the nests that we found
[00:15:34.817]were located on prairie dog colonies or burns,
[00:15:38.218]and these birds were selecting nest sites
[00:15:40.134]that had about the same amount of bare soil
[00:15:42.432]as random locations on prairie dog colonies and burns.
[00:15:45.896]So, we haven't done a lot of work
[00:15:48.609]quantifying the fitness components,
[00:15:50.586]but we see these birds really are selecting
[00:15:53.253]areas in the landscape with a lot of bare soil,
[00:15:55.208]short vegetation, and the only treatments
[00:15:58.418]that seem capable of getting us to that
[00:16:00.947]are burns and prairie dog colonies.
[00:16:03.584]So, why such a different response?
[00:16:06.498]So first of all, what I want to show with this graphic is,
[00:16:09.340]producing short vegetation is not a simple thing,
[00:16:12.488]as suggested by that original Knopf diagram.
[00:16:16.950]When you load up with a lot of cattle,
[00:16:19.192]we get increased dominance of blue grama,
[00:16:21.485]this top panel, we're looking down on short grass steppe
[00:16:24.272]that's been grazed very heavily
[00:16:25.856]for 10 years at double the recommended stocking rates,
[00:16:29.480]and you can see, there's not a lot of bare soil there.
[00:16:31.199]What happens is, blue grama is so resistant
[00:16:33.320]to that grazing that it maintains
[00:16:34.835]a short stature of almost a sod.
[00:16:37.360]It increases its basal cover,
[00:16:39.771]because it maintains a short layer
[00:16:43.549]that is essentially ungrazable by cattle.
[00:16:47.215]With burning, we can produce a one year pulse of bare soil
[00:16:50.927]by burning off the litter in the surface layer.
[00:16:53.743]This is a mountain plover nest in the middle here.
[00:16:56.534]But we have no effect on blue grama,
[00:16:58.333]and we actually have no effect on
[00:16:59.375]the plant species composition,
[00:17:00.698]it's just a short term result.
[00:17:02.744]And then, with prairie dog colonies,
[00:17:04.248]what we get over an increasing number of years
[00:17:06.383]of prairie dog colonization,
[00:17:08.323]we have, eventually start to get death of blue grama,
[00:17:12.389]transition to a more form dominated community.
[00:17:15.620]Again, a lot of bare soil where
[00:17:17.345]we find mountain plovers' nests.
[00:17:20.616]So effects of heavy grazing, prairie dogs and fire
[00:17:22.766]are different in this landscape.
[00:17:24.016]These differences are recognized by native species
[00:17:26.492]like the mountain plover,
[00:17:28.260]and then the last part of our work
[00:17:29.419]is they also have different
[00:17:30.653]economic implications for producers.
[00:17:33.556]One of our goals was to quantify that.
[00:17:36.021]In this upper treatment, this double stocking rate,
[00:17:39.032]this is completely economically unviable.
[00:17:41.238]At that doubling of stocking rate,
[00:17:44.398]the cattle are essentially losing weight
[00:17:46.379]for most of the summer.
[00:17:47.439]We were actually having to rotate cattle in and out.
[00:17:49.673]We couldn't leave the same individual animals
[00:17:51.401]on that pasture all summer, because they were losing weight.
[00:17:54.108]This is something a producer could never even do.
[00:17:57.082]They would have to be given significant incentives
[00:17:59.151]to stock at that rate.
[00:18:02.153]In terms of patch burns and livestock production,
[00:18:04.474]this is an example of one of our patch burns.
[00:18:06.678]In this study, we were burning
[00:18:08.381]a quarter of each pasture each year.
[00:18:11.033]This is a burn patch, and surrounding adjacent unburned.
[00:18:15.084]So with 25% of the pasture burned each year
[00:18:17.526]over a four year period,
[00:18:20.041]patch burned pastures are shown in red,
[00:18:22.842]and control unburned pastures are shown in blue,
[00:18:25.279]and this is livestock weight gains
[00:18:27.178]over that May to October grazing season.
[00:18:31.035]The pastures were burned for these four years,
[00:18:33.159]2008 through 2011, and over that time period,
[00:18:36.888]three of the four years, we had no effect,
[00:18:39.467]and then in 2010, which is an especially productive year
[00:18:41.848]with a lot of residual dead matter
[00:18:44.351]carried over from 2009, in that year
[00:18:46.854]we got a 10% increase in cattle weight gains with burning.
[00:18:49.574]So no negative effects, and at least in one year,
[00:18:52.177]a significant, and this 10% increase
[00:18:54.667]doesn't sound like a lot,
[00:18:55.921]but that is economically important.
[00:18:58.261]Then we hit a real drought in 2012,
[00:19:00.148]we didn't burn in this last year
[00:19:01.423]because of the drought, and that is the reason
[00:19:04.167]for this drop in weight gains,
[00:19:06.863]but there was no negative effects, again,
[00:19:09.023]of having previously burned in those pastures
[00:19:11.117]for the prior four years.
[00:19:14.452]In terms of prairie dogs,
[00:19:15.915]I'm currently running an experiment
[00:19:17.439]looking at prairie dog-cattle competition,
[00:19:19.259]and don't have those results worked up.
[00:19:20.917]This is a previous publication
[00:19:22.947]by my colleague Justin Derner,
[00:19:24.709]and what he showed is that
[00:19:25.812]as the percentage of a pasture
[00:19:27.343]got colonized by prairie dogs
[00:19:28.950]increases from zero to 60%,
[00:19:30.822]you get about a 15% decline in weight gains of yearlings,
[00:19:36.313]and my more recent work suggests
[00:19:38.815]this is going to be most important in drought years,
[00:19:42.565]and least detectable in wet years,
[00:19:45.015]but we're still working on quantifying that precisely.
[00:19:48.747]So in terms of conservation-production trade-offs,
[00:19:52.984]mountain plover conservation appears to be
[00:19:54.968]dependent on maintaining prairie dogs in the landscape
[00:19:58.877]and incorporating burning into management.
[00:20:02.054]The cost of prescribed burns,
[00:20:03.197]no negative effects of patch burning
[00:20:04.947]on forage or livestock production,
[00:20:07.376]even an enhancement in wet years,
[00:20:08.711]but then we have this effect of implementing,
[00:20:11.257]or this issue of implementation costs and feasibility.
[00:20:14.508]By feasibility, I mean really just the perception
[00:20:16.389]of risk by ranchers and whether they're willing to do it,
[00:20:19.519]and so, in my part of the world,
[00:20:21.656]there's a pretty strong negative perception of fire
[00:20:24.483]by the ranching community,
[00:20:26.514]and that still remains a pretty big impediment
[00:20:28.759]to using it as a management tool.
[00:20:31.877]In terms of prairie dogs, losses are dependent
[00:20:33.501]on the proportion of a pasture occupied
[00:20:37.117]and also likely to vary with weather.
[00:20:40.957]We see reduced livestock weight gains
[00:20:42.938]or if you're running a cow calf operation,
[00:20:45.139]you're going to have to have reduced stocking rates.
[00:20:47.838]And then in addition, when you get into those years
[00:20:49.736]where prairie dogs are particularly abundant,
[00:20:52.645]you have additional costs of controlling them
[00:20:54.629]if you don't want them to expand further.
[00:20:59.391]Okay, so that's all focused on a single species here,
[00:21:02.866]mainly precipitated by the fact that
[00:21:04.389]it was the rarest species and most likely to be
[00:21:06.545]listed under the endangered species act.
[00:21:08.852]But how do these different management strategies
[00:21:10.978]affect the full suite of grassland birds?
[00:21:13.879]We've also done some work looking across
[00:21:15.716]all six of these species shown here.
[00:21:18.009]They are ranged left to right in terms of
[00:21:19.966]their association with vegetation structure,
[00:21:23.757]so mountain plover, then McCown's longspur,
[00:21:25.762]horn lark, lark bunting, western meadowlark
[00:21:28.385]and grasshopper sparrows.
[00:21:30.109]Here in Colorado, we think of grasshopper sparrows
[00:21:33.467]and meadowlarks as nesting in tall grass.
[00:21:35.825]I assume here in Nebraska you think of them
[00:21:37.831]as perhaps the opposite,
[00:21:40.639]but they're a tall grass species.
[00:21:43.519]In terms of these two species,
[00:21:45.159]lark bunting and grasshopper sparrows,
[00:21:47.562]what we found is if you look across a gradient
[00:21:50.067]of burn age, from recent burns to three year old burns,
[00:21:53.720]lark buntings are significantly reduced in abundance.
[00:21:58.141]Grasshopper sparrows disappear when
[00:22:00.303]you implement burns for the first two years.
[00:22:02.715]Still severely reduced on three year burns,
[00:22:05.547]and most abundant in pastures managed without burning.
[00:22:09.802]So we see these species on the other side
[00:22:12.149]of the structural gradient not responding to
[00:22:15.299]the prescribed burning, or the patch burning management
[00:22:18.637]in a way that we had hoped,
[00:22:21.046]and what we found, patch burning does generate
[00:22:23.178]short structure habitat in recently burned
[00:22:25.211]and grazed areas, but it does that without
[00:22:27.683]increasing structure in unburned areas,
[00:22:29.658]so it's not pulling the cattle off of
[00:22:31.251]unburned areas enough to allow that vegetation
[00:22:33.857]to increase and provide habitat for
[00:22:35.849]other types of species.
[00:22:38.383]So an effective management strategy
[00:22:40.027]for mountain plover conservation
[00:22:41.276]that doesn't sustain the full suite
[00:22:43.117]of grassland bird species.
[00:22:46.616]So this leads into work that we've started
[00:22:48.798]more recently, started thinking about,
[00:22:50.885]what other management strategies can we use
[00:22:53.144]to produce this broader suite of rangeland heterogeneity?
[00:22:59.727]Another thing I learned from my patch burning work,
[00:23:03.224]I learned a lot about how people think
[00:23:05.616]and react to new information.
[00:23:08.060]Basically, most of the ranchers that I work with,
[00:23:10.015]in spite of the fact that we know each other pretty well,
[00:23:12.956]when I bring them results from my burning research
[00:23:15.947]or show them results, it was pretty much,
[00:23:17.986]well, I just don't like that result, or I don't believe you.
[00:23:22.599]So, for the second round of work,
[00:23:24.611]what we decided is to try a more collaborative approach
[00:23:27.154]that would bring people into our research station
[00:23:30.309]and have them help design the experiments
[00:23:32.571]and conduct the experiments with us.
[00:23:35.892]So we put together this Collaborative Adaptive
[00:23:37.460]Grazing Management for Beef and Birds project.
[00:23:41.897]What it involves, we have 11 stakeholders.
[00:23:44.339]I'll tell you who they are in a moment.
[00:23:45.836]It involves ten square miles of land that
[00:23:48.015]we set aside for the experiment,
[00:23:51.440]and uses about 450 steers in a ten year time frame.
[00:23:54.753]Another thing we found is,
[00:23:56.581]trying to conduct management research
[00:23:58.766]on the time frame of a graduate degree
[00:24:01.389]is really not feasible, and we often don't see
[00:24:04.721]effects in the short time scale
[00:24:06.567]because of the amount of weather fluctuation
[00:24:08.626]we get in the short grass steppe.
[00:24:10.539]So, this experiment, we are fortunate in ARS
[00:24:12.922]to commit to a 10 year time frame.
[00:24:16.070]This is how it looks.
[00:24:17.879]We've set up, we have ten pastures in yellow
[00:24:20.525]that are assigned to a traditional
[00:24:21.912]grazing management treatment.
[00:24:23.513]This is a continuous, season-long grazing treatment,
[00:24:27.336]very much like how allotments are managed
[00:24:29.301]on most of the national grasslands,
[00:24:30.809]and so cattle come in in May and they leave in October,
[00:24:35.245]and each yellow pasture gets its own herd.
[00:24:39.532]For the blue pastures, we say,
[00:24:40.684]we're gonna give this land to the stakeholder group,
[00:24:42.771]and we're gonna give you the same number of cattle,
[00:24:45.278]and you can manage it however you want.
[00:24:47.546]First you have to decide what you want to manage it for,
[00:24:50.034]and then you can decide how
[00:24:52.066]you want to go about managing it.
[00:24:54.249]So they met, the stakeholder group has four ranchers,
[00:24:57.423]they provide the cattle for the study,
[00:25:00.322]and then we have three NGO representatives,
[00:25:02.604]Nature Conservancy, Environmental Defense Fund,
[00:25:05.481]and Bird Conservancy of the Rockies,
[00:25:07.664]and then we have four representatives from agencies,
[00:25:09.889]NRCS, Forest Service, State Land Board,
[00:25:15.021]and CSU extension.
[00:25:17.218]So these eleven folks meet three times a year.
[00:25:19.541]The first couple of meetings, they decided on
[00:25:22.228]goals and objectives collectively.
[00:25:24.887]They decided that they had three broad sets of goals,
[00:25:28.019]vegetation, profitable ranching, and wildlife,
[00:25:31.427]and then they developed a suite of
[00:25:34.173]specific objectives that they wanted to see
[00:25:36.308]this land produce over the next ten years.
[00:25:39.762]Some of these, one I want to focus on here
[00:25:41.867]is this increased variation of vegetation structure,
[00:25:44.739]composition and density.
[00:25:46.694]So the NGOs in particular and, to some extent,
[00:25:49.485]the agency folks really wanted to focus on
[00:25:51.940]managing for this heterogeneity goal,
[00:25:55.163]as a proxy for biodiversity, but of course,
[00:25:59.147]we wanted to maintain or increase livestock weight gain.
[00:26:02.893]Another big deal for the ranchers was
[00:26:04.358]to reduce economic impact with drought years,
[00:26:06.570]so stabilize livestock numbers over time,
[00:26:10.872]and then manage for the full suite
[00:26:12.711]of grassland bird species.
[00:26:16.618]So what they decided to do for
[00:26:18.690]the initial few years of this study
[00:26:20.971]was to group all of their cattle
[00:26:23.309]into one herd of 225 steers,
[00:26:25.403]is approximately where they started.
[00:26:26.982]They can also adjust stocking rate annually
[00:26:28.598]however they like.
[00:26:31.106]They decided they want to rest
[00:26:32.499]two of these pastures each year,
[00:26:34.428]managing for this taller structure end of the gradient,
[00:26:37.547]and then rotate or move cattle among
[00:26:39.566]the remaining eight pastures based on,
[00:26:41.929]adaptively based on precipitation,
[00:26:44.822]forage biomass, species composition and seasonality.
[00:26:49.955]The way this worked out, so 2013,
[00:26:51.480]we did pre-treatment measurements on all these pastures
[00:26:53.870]and managed them all the same,
[00:26:55.006]continuous, season-long to get an initial baseline,
[00:26:58.547]and then we've been running this for three years,
[00:27:00.119]so 2014 through 16, we've been through
[00:27:02.617]two wet years so far, and one slightly dry year, 2016.
[00:27:07.442]So we certainly haven't had any drought to deal with.
[00:27:11.863]Most of the adjustments year to year so far
[00:27:13.908]have been in terms of the exact criteria used
[00:27:16.587]to move cattle among the pastures.
[00:27:19.703]In terms of monitoring, I've been measuring
[00:27:22.182]livestock responses, vegetation responses,
[00:27:25.449]vegetation in terms of cover, composition and structure,
[00:27:28.940]and we were also monitoring abundance and,
[00:27:31.270]to some extent, the reproductive success
[00:27:33.534]of grassland bird species.
[00:27:37.400]This is just an example of what it looked like in 2014.
[00:27:40.750]Because it was wet, we actually only ended up
[00:27:43.476]needing to use seven of the ten pastures,
[00:27:46.291]so the cattle rotated through like this,
[00:27:48.649]based on the criteria that the stakeholders set,
[00:27:51.020]and these three were rested, and then each year,
[00:27:53.711]they're planning different pastures for rest.
[00:27:58.222]Okay, so what have we seen so far?
[00:28:00.556]So in terms of cattle weight gains,
[00:28:01.927]to me, this is the most surprising result.
[00:28:04.754]I expected that when you group cattle up
[00:28:06.698]into a big herd that you're going to have
[00:28:09.139]some impacts on foraging selectivity.
[00:28:11.835]Selectivity of foraging is going to go down,
[00:28:14.060]and it can have some negative effects on weight gain.
[00:28:16.858]What I didn't expect was how big it would be.
[00:28:18.430]So in 2013 pre-treat, or both sides managed the same way,
[00:28:23.660]we get the same weight gains.
[00:28:25.639]2014, we see that our adaptively managed herd
[00:28:28.557]has 15% lower weight gains than the traditional approach,
[00:28:32.490]and that continues all the way out,
[00:28:33.915]so we're losing about 10 to 15% of the production
[00:28:37.969]on this adaptive herd, compared to
[00:28:39.854]spreading the animals out evenly.
[00:28:42.251]This speaks to why it's a traditional
[00:28:44.998]grazing management approach,
[00:28:46.817]and why we spread them out evenly.
[00:28:51.628]And the mechanisms underlying this,
[00:28:53.647]we also every Friday, there's a graduate student
[00:28:56.915]who gets to go out and collect fresh poop samples
[00:28:59.434]from all the herds, and we send those to
[00:29:02.999]the GanLab at Texas A & M,
[00:29:04.911]get accrued protein in the diet,
[00:29:07.322]and you can see here, the red bars,
[00:29:09.638]that's the traditionally managed herds,
[00:29:12.006]really high forage quality,
[00:29:13.697]especially early in the spring,
[00:29:14.976]because they're able to forage very selectively,
[00:29:17.322]because they're at a lower stock density.
[00:29:20.365]This higher stock density herd in the black
[00:29:22.944]is foraging less selectively
[00:29:24.397]and getting less accrued protein,
[00:29:25.673]and this difference early in the season
[00:29:27.089]is probably related most to those weight gain differences.
[00:29:31.321]Then we also have GPS collars on about 10%
[00:29:34.194]of the animals in the experiment.
[00:29:36.781]This is an example of foraging distributions,
[00:29:39.497]this is two steers tracked every five minutes
[00:29:42.710]for the dates shown here at the top.
[00:29:45.122]The top is two steers in a herd of 22,
[00:29:48.064]and this is two steers in a herd of 225.
[00:29:52.596]And you can really see a difference
[00:29:54.312]in the foraging patterns.
[00:29:56.020]This is what I call the clumpy foraging pattern,
[00:29:58.708]and this is what I call the spiderweb foraging pattern.
[00:30:01.763]You can just see, there's more straight lines
[00:30:05.005]and more distinct foraging pathways,
[00:30:07.405]compared to what you see up here
[00:30:09.215]under the traditional management.
[00:30:12.430]This really reflects the same thing we're seeing
[00:30:14.959]with the forage quality.
[00:30:16.687]When they're in these large herds,
[00:30:17.999]this is another example,
[00:30:20.349]this is the large herd and the small herd.
[00:30:23.523]Here they're foraging in more tortuous pathways,
[00:30:26.874]and here they're foraging in more straight line patterns
[00:30:28.886]and being less selective.
[00:30:30.787]To quantify this, this is from four pairwise comparisons
[00:30:33.294]that I've just had time to calculate
[00:30:36.234]from the 2015 grazing season.
[00:30:38.712]You can see this adaptive herd is
[00:30:40.775]spending less time foraging, more time ruminating
[00:30:44.343]compared to the traditional herd.
[00:30:46.614]They're foraging in straighter pathways,
[00:30:49.030]so their foraging angles are closer to 180 degrees
[00:30:51.643]compared to these guys who are foraging
[00:30:53.180]in more tortuous pathways.
[00:30:56.150]They're moving a longer straight line distance
[00:31:00.726]during the times when they're grazing.
[00:31:05.104]I'm looking forward to looking more at these data,
[00:31:06.735]but this is all I've gotten to so far.
[00:31:09.306]So other objectives, in terms of vegetation heterogeneity,
[00:31:12.993]what did we get out of this?
[00:31:15.399]We did, we were quite successful in
[00:31:17.241]increasing heterogeneity at the scale of the landscape,
[00:31:20.219]so variance among all pastures,
[00:31:22.583]among all 10 AGM pastures is about four times higher
[00:31:26.796]than the variance in traditionally managed pastures,
[00:31:29.584]and this is a measurement of vegetation structure
[00:31:31.225]in October, at the end of the grazing season,
[00:31:33.684]and that vegetation structure you have in the fall
[00:31:36.518]sets the stage for what kind of habitats
[00:31:38.319]you have for birds the following spring.
[00:31:41.139]And then various variants among all the plots,
[00:31:43.415]we have four to six monitoring sites in each pasture.
[00:31:46.801]If we look at variance among all those monitoring sites,
[00:31:49.761]it's about two times higher under
[00:31:51.068]adaptive management compared to traditional.
[00:31:53.553]So we're increasing vegetation heterogeneity.
[00:31:56.312]Are we getting anything out on the grassland bird side?
[00:31:59.714]Well, this is when we get into
[00:32:02.010]the time scale of experiments.
[00:32:04.908]We haven't seen responses of
[00:32:06.217]most of the bird species so far.
[00:32:07.939]The only species that we've seen a response
[00:32:10.308]is the grasshopper sparrow, and that really is
[00:32:12.294]just here in year three of the experiment.
[00:32:14.625]So the first three years, first two years,
[00:32:17.514]2014 and '15, abundance of grasshopper sparrows
[00:32:20.925]in both treatments remained quite similar,
[00:32:23.958]almost on top of each other, but a divergence here,
[00:32:26.681]and this is directly related to a large number
[00:32:29.311]of pastures being rested in 2015
[00:32:31.667]because it was a productive year,
[00:32:33.780]and so we had a statistically significant,
[00:32:36.726]or significantly greater grasshopper sparrow abundance
[00:32:38.975]in those pastures that were rested the previous year
[00:32:42.070]during the 2016 breeding season.
[00:32:46.390]So the tradeoffs we see so far,
[00:32:47.800]we do see a clear tradeoff.
[00:32:49.656]We're losing cattle weight gain,
[00:32:52.391]we're enhancing landscape scale heterogeneity,
[00:32:54.463]which was set out as one of
[00:32:55.479]the goals from the beginning,
[00:32:57.267]and we're increasing habitat for grasshopper sparrows,
[00:32:59.794]but we are also wondering about future drought mitigation.
[00:33:04.268]Coming into this next grazing season,
[00:33:05.878]the ranchers on the stakeholder group
[00:33:07.885]have agreed to continue moving forward
[00:33:09.254]with the same management,
[00:33:10.290]they don't want to change it quite yet,
[00:33:12.055]because they really want to see
[00:33:13.597]what they're going to get in a drought year
[00:33:15.784]out of this past management.
[00:33:18.130]So yes, we have lost, there have been some
[00:33:20.243]significant losses in terms of weight gain
[00:33:22.287]with the first three years,
[00:33:23.697]but we would like to see what happens
[00:33:25.385]with future drought mitigation.
[00:33:29.331]Okay, so some conclusions from all of this.
[00:33:31.271]First of all, I think very generally,
[00:33:32.716]enhancing spacial heterogeneity on the landscape
[00:33:34.782]is really important for grassland bird conservation,
[00:33:37.623]and I think this is well known
[00:33:39.050]for tall grass prairies, there's been a lot
[00:33:40.514]published on that out of Oklahoma and Kansas,
[00:33:43.486]but I think we're starting to see that
[00:33:45.555]it really is a general principle,
[00:33:47.132]at least across the Great Plains,
[00:33:48.433]including the semi-arid parts of it.
[00:33:51.758]However, there's no one optimal management regime or tool.
[00:33:55.797]I think a lot of what we do in extension
[00:33:58.674]is try to promote a single way of fixing things
[00:34:01.278]or making things better on rangelands,
[00:34:03.903]when it might be more valuable
[00:34:05.765]from a biodiversity standpoint to think about
[00:34:07.366]how can we be promoting a diversity of management regimes.
[00:34:11.435]In terms of the western Great Plains,
[00:34:13.817]on my dry side of the world,
[00:34:16.320]what we see with these three different,
[00:34:18.216]these three different management strategies
[00:34:20.288]have all generated increased heterogeneity
[00:34:22.411]on the landscape and all contributed
[00:34:23.817]in some way to enhancing populations
[00:34:26.156]of grassland birds that we care about.
[00:34:28.347]What are their consequences?
[00:34:29.703]So, with patch burn grazing,
[00:34:31.144]we have no lost beef production,
[00:34:32.476]but we've got burn implementation issues.
[00:34:34.779]Prairie dog restoration, we've got losses
[00:34:37.117]anywhere from zero to 15% in terms of beef production
[00:34:41.096]and most of your issues in drought,
[00:34:44.888]and then also issues with population control
[00:34:47.195]when they become abundant.
[00:34:49.172]With rest rotation grazing, we've got 10 to 15% loss
[00:34:51.670]of weight gain in wet years, and fence and water improvement
[00:34:54.556]and infrastructure costs as well.
[00:34:57.266]So I think what this means is
[00:34:58.194]if we want to enhance heterogeneity of the landscape,
[00:35:00.386]we really do need to be thinking about
[00:35:02.431]financial or other types of incentives
[00:35:04.686]in how can we offset the cost to livestock production,
[00:35:09.417]and then finally, for me, as an applied ecologist
[00:35:13.333]who doesn't think a lot about human dimensions,
[00:35:16.297]I've been learning a lot more about them
[00:35:17.883]through this collaborative approach,
[00:35:19.436]and yet collaborative research does seem to be
[00:35:21.704]increasing trust and communication among
[00:35:23.764]NGOs and the ranching community,
[00:35:26.719]but it is certainly a frustratingly slow process.
[00:35:31.089]So that's all I'll say, if you're interested more
[00:35:32.595]in the adaptive grazing management experiment,
[00:35:35.500]because I work for a federal agency,
[00:35:36.789]we can't make decent websites,
[00:35:39.739]so we always have a strange URL,
[00:35:42.374]so if you want to find us, just try Googling
[00:35:44.540]ARS adaptive grazing management,
[00:35:47.325]and I'd be happy to answer questions,
[00:35:50.319]now and also through email, if you have them.
[00:35:52.957]Thanks.
[00:35:54.987](applause)
[00:35:58.250]Thanks, David.
[00:35:59.604]With the collaborative process,
[00:36:01.433]they all agreed on priorities in those
[00:36:05.040]three different categories.
[00:36:07.788]What was the process like of thinking about
[00:36:10.061]how to prioritize those priorities?
[00:36:13.720]Yeah, so, very good question.
[00:36:17.220]There was, that process doesn't exist.
[00:36:21.918]I mean, at the first set of meetings,
[00:36:23.878]it was basically, here's what we think
[00:36:25.689]we can manage for all these things at the same time.
[00:36:29.570]And that was really the discussion that the group had.
[00:36:32.845]I was sitting there thinking, this is not possible,
[00:36:36.152]to manage for all these things at the same time,
[00:36:38.670]but okay, I'm just gonna see what happens here.
[00:36:41.443]And so we haven't set, we haven't, like,
[00:36:45.359]put numbers to the value of all these different objectives.
[00:36:50.923]We thought about doing that,
[00:36:52.160]but I think that would've been
[00:36:53.411]a very stressful experience for the stakeholders
[00:36:56.055]and could've derailed the project completely.
[00:37:00.007]We may do that, now that everybody knows each other
[00:37:02.348]a lot better, and things are moving forward.
[00:37:04.690]I think they're starting to realize now that
[00:37:06.178]at some point, we're gonna have to talk about that,
[00:37:09.585]or we'll have to use dollars as a way
[00:37:12.638]of quantifying what we're using, so I mean,
[00:37:15.067]what we have so far, I could probably
[00:37:16.628]take what we have right now and say
[00:37:18.378]I lost this much in beef production,
[00:37:20.588]go to an economist, find out the dollar value
[00:37:22.813]of that from 2016 and tell you exactly
[00:37:26.506]what it cost per grasshopper sparrow
[00:37:28.854]to get that increase in grasshopper sparrows,
[00:37:31.441]and I think if they knew what that cost,
[00:37:33.862]no one would want to pay that for grasshopper sparrows.
[00:37:38.127]But that's the way I can see it being quantified,
[00:37:41.825]in terms of the tradeoffs.
[00:37:59.561]So, I was curious if you have,
[00:38:01.844]or maybe someone else in your group
[00:38:03.084]has ringed any of your bird, your study species,
[00:38:06.452]and what these management techniques,
[00:38:08.534]how they might affect site fidelity,
[00:38:10.786]so return to the similar nesting area each season?
[00:38:15.244]And whether you think it'll have an effect,
[00:38:16.523]if you haven't studied this?
[00:38:18.164]Yeah, I think that's another important issue,
[00:38:20.744]and a good question.
[00:38:23.539]We don't have good data on that.
[00:38:25.365]One graduate dtudent is studying
[00:38:26.712]McCown's longspur at the site,
[00:38:28.583]and we have very small numbers of,
[00:38:30.644]she's been banding as many birds as she can
[00:38:33.747]during the first two years, and this year she,
[00:38:37.006]about 50% of the birds she banded in the first two years,
[00:38:39.593]she recaptured in the third year,
[00:38:42.144]which just amazed me, I mean, this tiny little bird,
[00:38:45.721]it's coming back to the same breeding territory
[00:38:48.639]the next year, so I think we are seeing
[00:38:50.948]more site fidelity than we thought,
[00:38:52.793]in the longspurs, and that raises the question,
[00:38:56.705]should you be managing the same pastures for them,
[00:38:59.355]year in and year out, instead of moving
[00:39:01.635]the structure around on the landscape,
[00:39:03.494]because they're always coming back to the same pasture,
[00:39:05.518]and they're finding the same birds in the same pasture,
[00:39:08.776]year after year, so that's an important question.
[00:39:11.219]The other species, like grasshopper sparrows
[00:39:13.197]and lark buntings I think do not have
[00:39:15.237]much site fidelity at all, they're very nomadic,
[00:39:18.362]and clearly the magnitude of population fluctuations
[00:39:21.290]that we're seeing on our site
[00:39:22.527]can not be explained by reproduction,
[00:39:25.436]and we just don't have a way of measuring
[00:39:27.781]or looking at that yet, because they're too small
[00:39:29.696]to carry GPS collars, probably soon,
[00:39:31.965]right, we can get them down.
[00:39:36.520]So if you're lucky enough
[00:39:37.667]to have a drought, like in 2012,
[00:39:39.832]during this 10-year experiment,
[00:39:41.378]what do you think the results would be then, for that year?
[00:39:46.889]I think it will depend in part
[00:39:48.366]in where they go with stocking rates,
[00:39:50.088]but if they maintain high stocking rates,
[00:39:52.183]if they're willing to maintain
[00:39:54.344]reasonably high stocking rates through the drought,
[00:39:57.080]I think you'll see improved production
[00:40:00.168]in the AGM treatment, because there is
[00:40:02.705]some grass banking going on there,
[00:40:04.394]and because of having long term rested pastures
[00:40:08.462]that you can turn cattle into towards
[00:40:10.192]the end of the grazing season,
[00:40:13.434]so I'd be interested to see that.
[00:40:15.641]If the stocking rates aren't high enough,
[00:40:17.339]it may not buy you much, so it depends.
[00:40:24.095]Yeah.
[00:40:26.612](audience member asking question without microphone)
[00:40:48.363]Yes, the problem is you can't measure everything,
[00:40:51.222]right, we've got several large grants
[00:40:53.584]supporting this, and I'm very happy
[00:40:55.181]of what we're able to monitor.
[00:40:58.495]I think that the reason we included heterogeneity
[00:41:03.685]in plant species composition and structure
[00:41:06.609]was as an attempt to, as an index of
[00:41:09.627]that overall value to biodiversity,
[00:41:14.251]and several of the NGOs involved
[00:41:16.608]recognized that from the outset,
[00:41:17.992]and that's why they wanted that heterogeneity objective
[00:41:20.531]included in the experiment,
[00:41:22.211]because they knew we can't measure everything,
[00:41:23.809]so let's at least have some index there.
[00:41:25.982]Pollinators would be interesting,
[00:41:28.115]there's also mammals, I'd love to know how,
[00:41:29.980]we have quite a few swift foxes on the site,
[00:41:33.267]I'd like to now how they're responding to the experiment.
[00:41:36.739]Antelope, there's all kinds of groups
[00:41:39.137]that could be responding, but the grassland bird
[00:41:41.429]was the one that we were able to get funded,
[00:41:45.587]and that there was the most interest in, for monitoring.
[00:41:49.964]So David, relative to that question,
[00:41:53.014]or related to that question then,
[00:41:54.807]you report two to four times
[00:41:57.861]greater heterogeneity in terms of
[00:42:00.062]structure and composition across that
[00:42:02.833]adaptive grazing management area,
[00:42:06.172]so why aren't you seeing much or any response
[00:42:09.378]from the bird community?
[00:42:13.367]Well, we do see a response, we have seen a response.
[00:42:17.064]I think what I showed there with the effects
[00:42:18.669]on grasshopper sparrows really is a response
[00:42:20.519]to that increase in heterogeneity
[00:42:21.983]on the tall structure side,
[00:42:23.610]so the adaptive grazing management treatment
[00:42:25.302]has rested pastures, pastures that were not
[00:42:27.409]grazed at all the previous year,
[00:42:29.167]and those are the pastures where we didn't really
[00:42:30.477]see a significant increase in grasshopper sparrows
[00:42:32.949]relative to the traditional,
[00:42:35.020]their paired traditional management sites.
[00:42:38.869]On the other side of the gradient,
[00:42:40.251]there was intensively grazed sites,
[00:42:42.979]the more intensively grazed pastures,
[00:42:44.554]we haven't seen a response from the short grass species,
[00:42:48.627]and I think that's simply because we
[00:42:49.708]haven't grazed it heavy enough,
[00:42:51.225]we're not able to get there, and it may be related,
[00:42:54.797]in part, to that site fidelity issue that we're,
[00:42:57.615]where intensive grazing in one year
[00:42:59.928]was not in those pastures that would have
[00:43:02.124]been best intensively grazed for the short grass species,
[00:43:05.666]so we're still working through,
[00:43:07.165]how can we do this better in future years?
[00:43:14.029]Yeah.
[00:43:16.141](audience member asking question without microphone)
[00:43:36.465]Yes, yes, I agree.
[00:43:38.284]We don't know what's driving those
[00:43:39.568]long term declines, but you know,
[00:43:42.478]I really don't think the magnitude of those declines
[00:43:44.963]can be explained by habitat loss, outright habitat loss.
[00:43:49.847]It certainly could be something on the winter range,
[00:43:52.199]and the Bird Conservancy of the Rockies,
[00:43:54.167]that group that they have a representative
[00:43:55.949]on the stakeholder group, they have several folks
[00:43:59.795]that are working on full life cycle analyses
[00:44:02.008]for grasshopper sparrows and I think Baird's sparrows,
[00:44:06.130]so they have people, the folks that are working,
[00:44:09.422]basically tracking the birds up on
[00:44:11.694]their breeding range, then going down to Mexico,
[00:44:13.455]tracking them on the winter range
[00:44:15.164]and really trying to separate out the effects there.
[00:44:19.080]My argument is, I can't do anything in Mexico,
[00:44:22.815]so I'll do what I can on this side.
[00:44:27.893]Question about woody shrubs
[00:44:29.917]and heterogeneity, because if you read papers
[00:44:33.170]like from Sevilleta LTER in the 1980s,
[00:44:36.309]Schlesigner's paper in Science, the desertification,
[00:44:39.681]islands of fertility, you get shrub encroachment,
[00:44:41.920]you get too much heterogeneity,
[00:44:43.799]and you start to get this matrix of impoverishment,
[00:44:49.673]and so in these arid or semi-arid grasslands,
[00:44:55.420]is it clear whether, is there a threshold there?
[00:44:57.656]Can you get, can you go too far
[00:44:59.536]with this heterogeneity, and you start to get
[00:45:01.241]a woody species desertification phenomenon?
[00:45:05.705]I think it depends on where you are.
[00:45:08.159]Let me get my map of the U.S.
[00:45:12.784]It's a good question, but I don't think anything
[00:45:16.618]that's been done in Sevilleta
[00:45:21.717]really applies well, so Sevilleta's here,
[00:45:24.507]this is the northern Chihuahuan Desert.
[00:45:26.698]Actually, Schlesinger's work
[00:45:27.858]was out of Jornada.
[00:45:29.028]Jornada, yes.
[00:45:29.861]But yes, same point.
[00:45:30.851]But Sevilleta and Jornada are both
[00:45:32.075]in the Chihuahuan Desert biome, and yeah,
[00:45:34.968]they've got major issues there with shrub encroachment,
[00:45:37.411]long term transitions and permanent transitions
[00:45:40.005]from grassland to shrubland,
[00:45:43.508]but it's really a different climate
[00:45:45.701]down in that part of the world,
[00:45:47.915]and this is what I call the short grass steppe,
[00:45:49.564]this big zone right here,
[00:45:51.438]eastern Colorado, coming up in Nebraska,
[00:45:53.653]the very edge of the panhandle of Nebraska
[00:45:55.414]and down through eastern New Mexico,
[00:45:58.040]and this entire region here is where
[00:45:59.977]blue grama is the dominant grass species.
[00:46:03.333]I'm just always amazed by blue grama.
[00:46:05.527]It is such a grazing resistant species,
[00:46:07.776]and that's why we see the responses that we do
[00:46:09.887]in our really heavy grazing treatments,
[00:46:11.332]we don't get any, what you would call desertification
[00:46:15.465]or any kind of patch, bare soil patch formation
[00:46:19.281]that would increase connectivity of bare soil.
[00:46:23.549]Blue grama is just very good at
[00:46:25.274]maintaining basal cover across that region,
[00:46:27.702]as long as you're on soils that aren't really sandy.
[00:46:31.992]So yeah, I guess the answer is,
[00:46:33.655]it really depends on where you are
[00:46:36.542]and what the evolutionary history of
[00:46:37.994]those grasslands are relative to grazing.
[00:46:39.664]These Great Plains grasslands have 10,000 years
[00:46:42.878]of pretty intensive grazing history,
[00:46:44.717]and the Chihuahuan Desert grasslands don't,
[00:46:46.596]so I think that plays a role.
[00:46:59.158]And on a completely different subject,
[00:47:02.684]while these collaborative, were you part
[00:47:04.192]of the collaborative discussions,
[00:47:05.491]kind of a fly on the wall, or taking part?
[00:47:09.684]Interestingly, I usually get stuck being the facilitator.
[00:47:12.814]I don't know how that happened,
[00:47:14.603]because I'm probably the worst person to do that.
[00:47:17.545]Yeah, I'm involved, but I'm not officially a stakeholder.
[00:47:21.073]You say you're dabbling more
[00:47:22.305]in human dimensions, so I'll throw this question at you.
[00:47:24.974]So, the occupation of the wildlife refuge
[00:47:28.391]over grazing issues occurred in Oregon
[00:47:30.838]during the evolution of this collaborative group.
[00:47:35.748]What were the discussions like?
[00:47:39.491]Is the collaboration serving a political role
[00:47:44.407]of helping to depolarize some of these
[00:47:46.540]other issues in the West?
[00:47:49.559]I think that the ranchers we're working with
[00:47:53.841]are clearly a much more reasonable group of people.
[00:47:56.486]They weren't Bundys.
[00:48:00.755]I do think that there is animosity
[00:48:02.833]and mistrust between the ranching communities
[00:48:05.179]in eastern Colorado and the front range urban communities,
[00:48:08.057]and this project is bringing those two groups together,
[00:48:11.907]but it's nothing like what was observed there in Oregon.
[00:48:16.144]I don't think, you know, all of the ranchers
[00:48:18.006]in our project, and there's a broader group,
[00:48:20.810]two grazing associations that we work with,
[00:48:23.285]they're all grazing on public land,
[00:48:25.646]but they don't have this attitude that we should own it.
[00:48:28.796]So I guess that's the difference, they realize,
[00:48:30.494]they seem to accept that their state has urban zones,
[00:48:34.536]and those urban people care about public lands,
[00:48:37.112]and they're going to have to deal with them.
[00:48:39.513]So I guess that's, maybe a fundamental difference
[00:48:43.703]between the two areas.
[00:48:45.307]It did come up, and they mostly
[00:48:46.426]just kind of laughed about it.
[00:48:57.769]Okay, well, thank you for speaking.
[00:49:01.657]No more questions, okay, thanks.
[00:49:06.723](applause)

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Adaptive grazing management to optimize cattle performance and rangeland bird diversity and abundance

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