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Graduate Student Theses, Dissertations, & Professional Papers Graduate School

2016

CORE ZONES, LIVESTOCK AND POPULATION ECOLOGY OF IN ’S GOBI STEPPE

Lars Stefan Ekernas

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This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. CORE ZONES, LIVESTOCK AND POPULATION ECOLOGY OF ARGALI IN

MONGOLIA’S GOBI STEPPE

By

LARS STEFAN EKERNAS

B.A. Dartmouth College, Hanover, NH, 2001 M.A. Columbia University, New York, NY, 2005 M.S. University of Montana, Missoula, MT, 2010

Dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Wildlife Biology

The University of Montana, Missoula, MT

September 2016

Approved by:

Scott Whittenburg, Dean of The Graduate School Graduate School

Joel Berger, Co-Chair Colorado State University

Paul M. Lukacs, Co-Chair Wildlife Biology Program

Jon Graham Department of Mathematical Sciences

John Maron Division of Biological Sciences

L. Scott Mills Wildlife Biology Program

© COPYRIGHT

By

Lars Stefan Ekernas

2016

All Rights Reserved

Ekernas, Lars Stefan, Ph.D., Autumn 2016 Wildlife Biology

Core zones, livestock, and population ecology of argali in Mongolia’s Gobi steppe

Co-Chair: Joel Berger

Co-Chair: Paul M. Lukacs

Core zones are established to reduce anthropogenic disturbance under the assumption that they protect biodiversity, yet this assumption has rarely been tested. In Central , increasing livestock density threatens 70% of large including in protected areas where livestock often constitute ~95% of biomass. A resulting conundrum is that local pastoralists are both key threats and crucial allies to conservation. Core zones, which reduce disturbance in small areas of important habitat, offer a potential solution to support wildlife and indigenous livelihoods. For my dissertation, I capitalize on a manipulation spanning 12 years to evaluate wild argali ( ammon) responses to reducing livestock density by 40% inside a core zone in Mongolia’s Gobi steppe. I investigate direct and indirect pathways through which pastoralists affect argali; quantify effects of livestock reduction on argali birth mass, survival, and population growth; and improve methods for monitoring argali populations throughout Central Asia. Because pastoralists influence plant, herbivore, and predator communities, they can affect argali through diverse pathways. Pastoralists alter predation pressure from both native and introduced carnivores, and their livestock probably compete with argali for food. I found that livestock reduction strongly affected argali, increasing argali birth mass by 18%, increasing juvenile survival from pre-reduction 19% to post-reduction 51%, and increasing argali population growth by 9% annually from 0.91 to 1.00. I found clear signals that argali are resource limited, since livestock reduction plus normalized difference vegetation index (NDVI) explained 97% of the annual variation in cohort lamb survival and explained 90% of the annual variation in asymptotic population growth. My analyses therefore reveal that livestock detrimentally affect argali and simultaneously provide empirical evidence that core zones can mitigate these effects. I also develop methods for monitoring argali populations using lamb:ewe ratios, from which I can infer population trend if adult survival at my study site is incorporated as a ceiling that can be attained but not surpassed at other locations. Lamb:ewe ratios are simple, inexpensive and can engage local communities in conservation efforts. In totality my dissertation advances conservation of argali while broadly yielding insight on a complex ecological process, interspecific competition.

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ACKNOWLEDGEMENTS

Completing – in fact even getting to – this dissertation was a long and circuitous route. I wouldn’t have gotten here without a staggering amount of help. First and foremost in guiding me has been my advisor Joel Berger. Joel has been an ardent supporter throughout the ups and the downs, has placed unwavering trust in me, offered up his time, house, beer, and coffee too generously on too many occasions to count, and for that I will always be deeply grateful. Joel’s phenomenal creativity, commitment to conservation, and speed up mountainsides provide goal posts that continue to push me. I am enormously indebted to Rich Reading, who offered me unfettered access to a dataset that took him almost 20 years and several million dollars of fundraising to collect. I hope my resulting contributions to argali conservation partially repay his graciousness.

Paul Lukacs took on the reins as my co-advisor in the last year, for which I am greatly appreciative. I also extend a deep thanks to my committee members Jon Graham,

John Maron, Scott Mills, and Dan Pletscher (emeritus) for their insights, valuable advice, and availability.

My wife Karen has been an unyielding source of strength in supporting me to both start and finish my Ph.D., which was without question harder on her than it was on me. As with all things, she has gone through this process with remarkable tenacity and grace. Despite me telling them, I don’t think my little ones Elin and Anders can ever understand how much inspiration and joy they continue to give me. I suspect the same is true for my loving parents Anders and Mariann, who probably didn’t expect the chips to fall quite this way when they fervently supported I follow my passions wherever they take me.

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Gana Wingard has been a phenomenal friend and collaborator in Mongolia and at

Denver Zoo. Gana, T. Selenge, and Sukh Amgalanbaatar introduced me to Mongolia and went out of their way to make all my trips smooth and productive. Onoloo, Oogi, Remo,

Batdorj, Ankhaa, Nandin, Chimidee, and all the other students and staff at Ikh Nart

Nature Reserve made it an absolute pleasure to work there. For much of the last four years I’ve put my office in Denver Zoo, and I feel tremendously fortunate to have been a part of that great team alongside Rich Reading, Gana Wingard, Kyoko Wilson, Erin

Stotz, Nanette Bragin, Matt Herbert, Amy Levine, Kel Rayens, Rebecca Garvoille, Erica

Garroutte, Heather Batts, Luis Ramirez, Dave Kenny, Kevin Fitzgerald, and Graeme

Patterson.

My Berger lab mates Wesley Sarmento, Theresa Laverty, and Nick Sharp have been true colleagues and friends. Through some strange aligning of the stars Wesley has meaningfully contributed field work to all four projects, spanning three continents, that

I’ve engaged in at various stages along the way to this dissertation. I hope he enjoyed it as much as I did. Cheryl Hojnowski and AJ Glueckert also volunteered their field work on some of those earlier projects. AJ put in many miles in the sagebrush and alpine with me, hauling mountain carcasses, checking perpetually empty jackrabbit traps at dawn, chasing a bear off his backpack, and counting hare poop on all fours without ever losing his positive attitude. AJ is the only person I know who is so genuine and enthusiastic that the simple phrase “How are you?” gets hikers to stop in their tracks to tell him how awesome their life is right now. Renee Seidler was a tremendous asset when

I worked in Wyoming, opening her house and going out of her way to show me the ropes in southern Greater Yellowstone.

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I sincerely thank Denver Zoological Foundation, Earthwatch Institute, and Trust

for Mutual Understanding for their long-term financial commitments to this project,

which spans 20 years for DZF. I feel very fortunate to have received as much financial

support as I did from Montana Ecology of Infectious Diseases (NSF grant DGE-

0504628), for which I am especially grateful to Bill Holben. I was also supported by the

Clancy Gordon Environmental Scholarship. During my time in southern Greater

Yellowstone I received funding from the Boyd Evison Graduate Research Fellowship

(organized by the Grand Teton Association) and the Montana Chapter of The Wildlife

Society.

Last I thank the people who call Ikh Nart home – Dandar, Uynga, Batbold,

Maikhant, Ulzii, Choka to name but a few – who have let me freely wander around their

home and audaciously interpret whatever I saw however I saw fit.

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TABLE OF CONTENTS ABSTRACT…………………………………………………………..………………..... iii ACKNOWLEDGEMENTS…….….……...…………………………………...………… iv TABLE OF CONTENTS………………………………………………………...………vii LIST OF TABLES…………...………………....…...……………………………….…… x LIST OF FIGURES……………………………………………………………………... xii CHAPTER 1. Introduction and overview……………………………………………….... 1 Background…………………………………………………………………………… 1 Research objectives……………………….……….……………………………….… 3 Summary of results……………….…………………………………………………... 8 Research significance…………….………………...……………………...………… 12 Conservation recommendation…………..…………….……………………………. 13 Develop schemes to reduce livestock and human-wildlife conflict…...... ………. 13 Implement and evaluate core zones……………………………………………... 13 Monitor argali population with age ratios...…………………………………..…. 14 Estimate survival for other to enable monitoring with age ratios...... 14 Dissertation format…………………………………………………………………... 15 Literature cited………………………………………………………………………. 15 CHAPTER 2. Desert pastoralists’ positive and negative effects on rare wildlife in the Gobi………………………………………………………………………………………21 Abstract……………………………………………………………………………… 21 Introduction………………………………………………………………………….. 22 Methods……………………………………………………………………………....24 Study site……………..…………………………………………………………. 24 Argali mortality, abundance, and diet…………………………………………… 25 Wolf diet………………………………………………………………………… 26 Assessing pastoralists’ attitudes towards wolves and argali……………...……... 27 Results………………………………………..……………………………………… 27 Domestic and native ungulate populations……………………………………… 27 Dietary overlap between livestock and argali………………………...…………. 28 Carnivore populations…………………………………………………...………. 28

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Wolf diet…………………………………………………………………....…… 29 Argali mortality causes……………………………………………………...…... 30 Livestock predation by wolves………………………………………………...... 31 Anthropogenic effects on wolves………………...…………………………….... 31 Attitudes of pastoralists…………………………..………………………………32 Discussion………………………….………………………………………………... 33 Key points of human-wildlife conflict……………………...…………………… 33 Indirect effects…...……………….…………………………………….……….. 36 Solutions to reduce human-wildlife conflict…………………………….………. 37 Conclusion………………………………………………………………………. 41 Acknowledgements……………..…………………………………………………… 42 Literature cited…………………………………………………………….………… 42 CHAPTER 3. Evaluating core zones in arid protected areas: argali in the Gobi steppe... 53 Abstract……………………………………………………………………………… 53 Introduction…………………………………………………………………………. 54 Methods…………………..…………………………………………………………. 57 Study site………………………………………………………………………… 57 Livestock manipulation………………………………………………….………. 58 The response variable: lamb birth mass.……………..………………….………. 59 Individual covariates: sex, Julian birthday, and age at capture…………….…… 60 Environmental covariates: NDVI, precipitation, and winter temperature…...….. 60 Statistical analysis…………………………………………………………….…. 62 Results……………………………………………………………..………………… 63 Lamb birth mass……………………………………………………………….… 63 Factors predicting lamb mass……………………………………………………. 63 Discussion………………………………………………………….……………...… 63 Acknowledgements…………….………………………………………………….… 66 Literature cited…………………………………………………………………….… 66 CHAPTER 4. Factors influencing survival of juvenile and adult argali in Mongolia’s Gobi steppe ...…………………………………………………………………………... 82 Abstract……………………………………………………………………………… 82

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Introduction………………….…………….………………………………………… 83 Methods………………………………………………………………………………86 Study site, core zone, and livestock reduction………….………….……………. 86 Argali captures………………………………………….……………………….. 87 Measuring environmental covariates: NDVI, precipitation, and winter temp.….. 87 Measuring argali survival: field and analytical methods…………………….….. 89 Results…………………………….…………………………………………………. 96 MCMC results……………………………….……………..……………………. 96 Survival of newborns, lambs, yearlings, and adults…………...………………… 96 Covariation between parameter estimates………………………………………. 97 Factors predicting survival…………………………….………………………… 97 Discussion………….………...……………………………………………………… 98 Acknowledgements………….………….………………………………………...... 101 Literature cited……………………………………………………………………... 101 CHAPTER 5. Livestock, core zones, and population dynamics of Gobi argali……….. 119 Abstract………………….….……………………………………………………… 119 Introduction…………….………….……………………………………………….. 120 Methods………………………….………………………………………………….122 Study site and livestock reduction………………..….………………………… 122 Statistical analyses and the integrated population model……………………… 123 Multistate mark-recapture survival analysis…………………………………… 123 Binomial survival analysis of skulls…………………………………………… 125 Retroactive population model: predict observed population vectors…….…..… 126 Stochastic population model to estimate population growth…………….…….. 132 Model construction…………………………………….…………...……… 132 Section I. Stochastic population growth over entire study, 2003-2013...….. 134

Section II. Estimating effect of livestock reduction on λs………………...... 137 Results……….………………………..……………….…………………………… 140 Improved vital rate estimates………………...………………………………… 140 Covariation between vital rates………………………………………………… 140 Vital rate sensitivities and elasticities...…………………...…………………… 140

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Effect of livestock reduction on vital rates…………………………………….. 141 Stochastic population growth…………………………….…………………….. 142 Discussion………………………………………………………………………….. 142 Literature cited……………………………………………………………………... 148 Appendix 5.1. Within-year correlations and one-year cross-correlations between argali vital rates…………..………………………………..…………………… 163 CHAPTER 6. Using group composition data to improve ungulate population monitoring in Central Asia………….……………………………………………………………… 164 Abstract……………………………………………………………………………. 162 Introduction………….…………………………………………………………….. 165 The mathematical model…………………………………………………………… 168 Key points for designing monitoring surveys…………...…………...………… 169 Case study: monitoring argali with limited survival data….…………...………….. 170 Background…………………………………………...... ……………………… 171 Survival, recruitment, and argali population growth at INNR….……………… 172 Using argali survival at INNR to inform population monitoring at other sites... 174 Discussion…………….……………………………………………………………. 177 Literature cited……………....………………………………….………………….. 179

LIST OF TABLES CHAPTER 2 Table 2.1. Prey remains at a wolf den in Ikh Nart Nature Reserve, Mongolia……… 49 Table 2.2. Cause-specific predation of VHF/GPS collared argali at Ikh Nart Nature

Reserve, Mongolia, from 2001-2013…………………………………………... 50

CHAPTER 3

Table 3.1. Studies evaluating effects of core zones on wildlife populations in arid regions

where the core zone represents only a fraction of target species’ home ranges……….. 76

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Table 3.2. General linear models predicting birth weight of argali lambs at Ikh Nart

Nature Reserve, Mongolia……………………………………………………… 78

CHAPTER 4

Table 4.1. Parameters estimated in the multistate survival model…………………. 107

Table 4.2. Candidate explanatory variables predicting yearly argali survival, specifying which age classes were affected, with what lag time(s), and what interaction effects we included……………………………………………...... 108 Table 4.3. MCMC results from the multistate model (n = 100,000 MCMC samples)……………………………………………………………………….. 109

Table 4.4. AICc comparison of general linear models predicting survival of argali (a) newborns (aged 0 months), and (b) lambs (aged 1-11 months), at Ikh Nart Nature Reserve, Mongolia, from 2003-2013…………………………………...……..111

CHAPTER 5 Table 5.1. Vital rate sensitivity and elasticity ……………………………………... 153

Table 5.2. Stochastic population growth (λs) pre- and post-livestock reduction as calculated using three methods………………………………………………... 154

CHAPTER 6 Table 6.1. Annual estimates of adult female argali (Ovis ammon) survival (S), pre- birth pulse lamb:ewe ratio (X), transient population growth rate from Equation 1 (λ), and status of livestock reduction at Ikh Nart Nature Reserve, Mongolia.... 190 Table 6.2. Age ratios reported from argali populations across Central Asia with inferred population trend (λ)…………………………………………………... 191 Table 6.3. Ungulate species native to Central Asia with published survival estimates and/or telemetry data, potentially enabling survival estimates and population monitoring via age ratios……………………………………………………… 194

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LIST OF FIGURES CHAPTER 2 Figure 2.1. In grazing systems where biomass (indicated by oval size) is dominated by pastoralists and their livestock and , wildlife interactions with pastoralists often intensify (bold arrows) while other interactions weaken (dotted arrows). Mechanisms through which pastoralists, native herbivores, and carnivores affect each other are listed next to arrows…………………………………………..… 50 Figure 2.2. Cause of death for VHF/GPS collared argali at Ikh Nart, 2001-2013…... 52

CHAPTER 3 Figure 3.1. Sampling design for argali lamb birth weights across a livestock before- after treatment in Ikh Nart Nature Reserve, Mongolia. Human and livestock density was reduced by 40% inside the core zone in 2006……………………...79 Figure 3.2. Argali lamb capture locations at Ikh Nart Nature Reserve, Mongolia, 2003-2013……………………………………………………………………….80 Figure 3.3. Argali lamb birth weights and NDVI at Ikh Nart Nature Reserve, Mongolia, 2003-2013…………………………………………………………... 81

CHAPTER 4 Figure 4.1. States and transitions for a single age class in the multistate model…... 113 Figure 4.2. Framework of the mark-recapture multistate model, incorporating both live recaptures and dead recoveries of collared (joint live-dead analysis, left column) but only live recaptures for uncollared animals (Jolly-Seber model, right column)…………………………………………………………………...114 Figure 4.3. Minimum convex polygon home ranges of GPS-collared adult argali (n = 10) in relation to Ikh Nart Nature Reserve, the core zone, and newborn capture locations (n=130). The core zone comprised 18-60% of most (n = 9) animals’ home ranges, but comprised only 1% of home range for one migratory individual……………………………………………………………………… 115 Figure 4.4. Histograms of posteriors from MCMC samples of simulated data…..... 116

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Figure 4.5. Monthly survival probability of argali adults, lambs, and newborns at Ikh Nart Nature Reserve, Mongolia, 2002-2012………………………………….. 117 Figure 4.6. Argali (a) newborn survival in the first month, and (b) lamb survival from1 month to 12 months (bars = standard error) in relation to Normalized Difference Vegetation Index at Ikh Nart Nature Reserve, Mongolia, from 2002- 2013…………………………………………………………………………… 118

CHAPTER 5 Figure 5.1. Components of the integrated population model………………………. 155 Figure 5.2. Retroactive population model that predicts observed population vectors (bold boxes) during 2003-2014 using survival rate parameters estimated from telemetry and skulls…………………………………………………………… 156 Figure 5.3. Lefkovitch matrix (A) and population vector (n) used in stochastic population model. R = reproductive rate, Sn = newborn survival, ySl = year-long lamb survival, ySy = year-long yearling survival, ySa = year-long adult survival………………………………………………………………………... 157 Figure 5.4. Parameter estimates and standard errors (bars) for vital rates calculated from mark-recapture analysis of telemetry data compared to results of the Integrated Population Model, which incorporates additional data sources…… 158 Figure 5.5. Sensitivity analysis for lower level vital rates. Slope of the regression is sensitivity, and r2 shows how much of the variation in λs each vital rate explains………………………………………………………………………... 159 Figure 5.6. (a) Argali newborn and (b) lamb survival at Ikh Nart Nature Reserve, Mongolia, in relation to NDVI and livestock reduction………………………. 160 Figure 5.7. Histograms of MCMC simulations showing effect of livestock reduction

on stochastic population growth (λs) as calculated using two techniques described in Methods Section IIA (Method 1) and Section IIB (Method 2)……….……. 161 Figure 5.8. NDVI in May in relation to asymptotic λ corrected for livestock reduction…………………………..…………………………………………... 162

CHAPTER 6

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Figure 6.1. Sites where we use reported argali (Ovis ammon) lamb:ewe age ratios to retrospectively infer transient population growth (shown in Table 6.2)…….... 195 Figure 6.2. Contour plot of transient population growth rates (λ) from paired adult female survival values and pre-birth pulse lamb:ewe ratios (following DeCesare et al. 2012). Values below the λ = 1 isocline represent negative population growth, and values above it represent positive population growth………...…. 196 Figure 6.3. Contour plot of transient population growth rates (λ) from adult female argali (Ovis ammon) survival and pre-birth pulse lamb:ewe ratios. We assume that long-term argali survival is maximized at our study site (Ikh Nart Nature Reserve) and set mean adult female survival at INNR ( = 0.844) as a ceiling that other locations can attain but not surpass………………………………… 197 Figure 6.4. Age ratios can immediately improve monitoring of Central Asian ungulates in the top row, for which adult female survival estimates have been published (Table 6.1); telemetry data but not survival estimates are available for species in the bottom two rows……………………………………………….. 198

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CHAPTER 1

INTRODUCTION AND OVERVIEW

BACKGROUND

In many of the world’s developing countries, livestock are central to rural livelihoods. Pastoralists have few economic opportunities and can most readily gain income by increasing livestock herds. Globalization of the cashmere market has accelerated these incentives, and in Mongolia cashmere-producing have increased from 5 million in 1990 to 19 million in 2013 (Berger et al. 2013; National Statistical

Office of Mongolia 2013). Current livestock densities have no historical antecedent and impose novel pressures on native biodiversity. IUCN (2015 Red List) classifies livestock as a “major threat” to 70% of Central Asia’s large species. Exacerbating the situation is that few refuges exist, since livestock account for ~95% of ungulate biomass in many protected areas across the region (Berger et al. 2013). The result is a conundrum wherein local pastoralists, who are often crucial allies in conservation, are also a primary threat to native biodiversity. Core zones that reduce human disturbance in small but biologically important areas have been posited as a solution to allow both wildlife and indigenous pastoralists to thrive (Mishra et al. 2010). However, core zones’ efficacy in conserving wildlife remains largely untested.

I use a combination of observational and experimental approaches to explore interspecific competition between livestock and native ungulates, and to evaluate whether core zones can alleviate potential detrimental effects. Interspecific competition is often considered a fundamental force shaping ecological communities (Hutchinson 1959).

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Demonstrating interspecific competition in communities has proven difficult

because most sympatric species have co-evolved to minimize competition by filling

different niches (Connell 1980). Theory predicts interspecific competition to be strong in

systems where competitors have had little chance to co-evolve and where few opportunities for niche separation exist. Potential competition between livestock and wild herbivores is in accord with this scenario, especially in arid rangelands outside the tropics where plant diversity and presumably niche space are restricted.

Some of the northern-most grasslands in the world are in Mongolia, where native herbivores have had limited opportunity to evolve in response to livestock which appeared 4000-5000 years ago (Ajmone-Marsan et al. 2010). The intensity of potential competition there is also unprecedented since livestock density is almost four times higher today than 20 years ago (Reading et al. 2010; National Statistical Office of

Mongolia 2013). Classic ecological theory predicts that when two sympatric species occupy the same niche, interspecific competition will drive one extinct (Gause 1934).

Preventing that fate is one of the central challenges facing Mongolia’s native ungulates and conservation practitioners.

Argali (Ovis ammon), the world’s largest sheep, occur in Central Asia’s deserts, steppes, and mountains. IUCN classifies the species as Near Threatened with range-wide population declines driven by poaching and livestock competition (Harris & Reading

2008). Available data suggest that competition between argali and livestock may be intense at my study site. Diet overlap between argali and domestic goats & sheep is high

(seasonally reaching 95% species overlap; Wingard et al. 2011a), livestock are ubiquitous in the areas where argali occur, they share the same small and scarce permanent water

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sources, and livestock outnumber argali roughly 50:1. These conditions provide an excellent system in which to investigate potential competitive effects and methods for mitigating competition.

To investigate these questions I performed field work spanning three seasons

(summer 2012, spring 2013, and fall 2013) at Ikh Nart Nature Reserve (“INNR”) in

Mongolia’s -steppe, and also relied on argali telemetry and demographic data collected by Denver Zoological Foundation over 12 years at the same study area. This is the largest dataset on any ungulate in Central Asia, and it encompasses a before-after livestock manipulation. Furthermore, INNR is the only site in Central Asia with concomitant socioecological data on pastoralists, native ungulates, and native carnivores.

These data offer unique opportunities to examine cause and consequence of multifaceted interrelationships among pastoralists and native species. My dissertation aims to identify and quantify these relationships, offer new insights about interspecific competition between livestock and native herbivores, and to enhance the possibility of conservation by clarifying the value of protected core zones.

RESEARCH OBJECTIVES

In designing this dissertation, my overarching goal has been to advance conservation in Central Asia and particularly for argali. To address this goal I investigate a pressing but elusive question: does interspecific competition with livestock detrimentally affect argali populations, and, if so, what can we do about it? I structured this dissertation to explicitly answer these questions while presenting readers with a synopsis of argali ecology and challenges to conservation. I begin by identifying

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numerous direct and indirect pathways through which pastoralists and livestock affect argali, focusing particularly on the role of predator-mediated effects (Chapter 2). In the next three chapters I explore the hypothesis that competition with livestock detrimentally affects argali, with each chapter testing one prediction (Chapters 3-5). I conclude by developing improved methods for monitoring argali populations across Central Asia, informed by data collected at INNR (Chapter 6).

The best way to identify effects of livestock on native species is to manipulate livestock density. In 2006, INNR’s Director (Sukh Amgalanbaatar, a co-author on all subsequent chapters) reduced human and livestock density by 40% inside a 71 km2 core zone of key argali habitat following the voluntary departure of several pastoral families.

Argali data collection began in 2002, and I treat livestock reduction as a before-after fixed effect while accounting for variation in environmental factors. I test three predictions using this manipulation, with predictions increasing in biological importance from a sub-vital rate, to a vital rate, to population growth: (1) reducing livestock density increases argali birth mass, (2) reducing livestock density increases survival of juvenile argali, and (3) reducing livestock density increases argali population growth.

I designed these predictions cognizant of my study design’s shortcomings. First is that the livestock reduction is neither replicated nor has a control site, which are problems that confound most studies of wild vertebrates in Asia. Lacking a control site means that environmental variation across the livestock treatment adds variation (noise) that I can only partially account for. Compounding this weakness, the livestock reduction underestimates livestock effects on argali because (1) domestics were reduced but not removed, and (2) reductions occurred only inside a core zone representing ~25% of

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occupied argali habitat. These latter two weaknesses decrease my ability to detect an effect, though they do not undermine any effects that I do detect. In other words the possibility exists for a Type II error, whereby I fail to detect a true effect. Indeed, if I find no effect of livestock reduction I cannot exclude the possibility of poor study design. On the other hand, a strength of my study design is that should I find any effects, I can infer both that livestock are the likely causal agent and that small core zones have potential to mitigate detrimental effects of livestock. Following are descriptions of my primary objective for each chapter.

 (Chapter 2) What are the direct and indirect pathways through which pastoralists

affect argali and wolves?

My first objective is to identify the multiple pathways by which pastoralists and their livestock affect argali, focusing particularly on predator-mediated effects. Gray wolves (Canis lupus) are the only native large carnivore at INNR capable of preying on adult argali, but pastoralists also keep domestic dogs (Canis familiaris) and these kill argali (Young et al. 2011). To identify effects of pastoralists on native wildlife, I synthesized socioecological data on pastoralists’ herding practices and husbandry; dog, wolf, livestock, and argali density; argali mortality causes; overlap between argali and livestock diet; and wolf diet and livestock predation.

 (Chapter 3) Does livestock reduction increase argali birth mass?

To explore the livestock competition hypothesis, I begin by investigating effects of livestock reduction on argali birth mass. Birth mass has numerous important health

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consequences and influences vital rates (Stanner et al. 1997). However, in terms of fitness, birth mass is almost certainly less consequential than vital rates such as survival and reproduction. Therefore birth mass should be more sensitive to changes in resource availability than vital rates, since parameters with low fitness effects generally encompass more variation (Pfister 1998). Birth mass also yields insight on causal mechanisms

underlying livestock effects because birth mass is a direct outcome of prenatal maternal

investment, which is a function of maternal body condition (Jones et al. 2005; Martin &

Festa-Bianchet 2010). Body condition is itself largely determined by resource availability

(Cook et al. 2004; Pettorelli et al. 2005). Increased birth mass following livestock reduction would logically be associated with a livestock-induced reduction in food available to argali.

 (Chapters 4 & 5) Does livestock reduction increase argali survival?

In Chapter 4 I test effects of livestock reduction on vital rates, namely survival of different age classes. I use telemetry data from n = 184 argali of all age-sex classes collected over 136 months at INNR. I analyze survival with a Bayesian multistate model that incorporates both live re-sightings and dead recoveries while accounting for imperfect detection of both. In addition to the parameters estimated by a standard joint live-dead analysis, my model estimates probability of VHF transmitter failure, which causes animals to transition to a state of lower detection probability. I use a combination of frequentist and Bayesian approaches to conduct model selection (following Kéry &

Royle 2015) and identify factors that predict temporal variation in survival, including

precipitation, winter temperature, normalized difference vegetation index (NDVI), lamb

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sex, birth mass, and livestock reduction in the core zone. In Chapter 5 I calculate survival using the same multistate model but also add information from other data sources that are independent from telemetry (see below).

 (Chapter 5) Does livestock reduction increase argali population growth? Which

argali vital rates are most important to population growth?

In Chapter 5 I translate effects of livestock reduction on vital rates (survival) to population growth, a parameter of paramount conservation concern. Specifically, I develop an integrated population model that incorporates multiple independent datasets to improve parameter estimates for vital rates, estimate stochastic population growth rate, and conduct sensitivity analyses for each vital rate. I also use these results to infer the degree to which argali are bottom-up limited by resource availability, which is important for understanding whether food competition with livestock occurs.

 (Chapter 6) What low-cost methods can reliably estimate argali population

growth?

In Central Asia, monitoring ungulate populations is hampered by few resources, poor infrastructure, difficult and variable terrain, and low density of target species. A few methods have been successfully implemented to assess population abundance – distance sampling transects (Young et al. 2010), mark resight (Wingard et al. 2011b), and double observer counts (Suryawanshi et al. 2012) – but results from these methods are usually too imprecise to measure population trend. Improving population monitoring methods is considered a “high priority” for ungulate conservation in Central Asia (Schaller et al.

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1998; Mallon et al. 2014). Building on methods developed in North America (Hatter &

Bergerud 1991; DeCesare et al. 2012), I demonstrate how to infer population growth from any argali population using young:female age ratios coupled with adult survival estimated at INNR set as a theoretical maximum. These methods substantially improve population monitoring methods for argali and potentially other ungulates in Central Asia.

Furthermore, I extend the ‘age ratios and survival’ method itself by demonstrating how to use it to infer population growth when knowledge about survival is incomplete.

SUMMARY OF RESULTS

 (Chapter 2) What are the direct and indirect pathways through which pastoralists

affect argali and wolves?

Pastoralists at INNR affect argali by decreasing forage availability, increasing disease risk, and increasing predation risk via introduced predators (dogs). Livestock outnumber argali 50:1 and remove approximately 10 times more forage, with ~90% overlap in key forage species during autumn, winter, and spring (Wingard et al. 2011a).

Disease accounts for 25% of collared adult argali mortalities, and livestock potentially amplify disease risks by serving as high density hosts. Pastoralists also keep dogs which kill argali of all age classes (Young et al. 2011), and dogs are by far the most abundant large carnivore since they outnumber wolves roughly 20:1.

Effects of pastoralists on wolves are both positive and negative. Although herders kill wolves, they also increase food supply for wolves via abundant livestock. All wolves

(n = 9) my collaborators and I sampled at INNR prey on livestock to varying extents, and livestock accounted for 96% of ungulate prey in the one wolf pack for which I have

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species-specific prey data. Wolves therefore benefit from livestock (Sharma et al. 2015).

On the detrimental side, wolves annually kill 1-4% of livestock at INNR (Davie et al.

2014) and pastoralists kill wolves in retribution. I do not have demographic data on

wolves to rigorously explore these relationships, but wolf density appears to be driven by

anthropogenic factors and decoupled from argali density. Consequently pastoralists can

have indirect effects on argali mediated by wolves. Pastoralists’ indirect effects may be

either positive if pastoralists decrease wolf predation on argali (apparent facilitation), or negative if pastoralists increase wolf density and predation on argali (apparent competition).

 (Chapter 3) Does livestock reduction increase argali birth mass?

I analyzed birth mass of newborn argali (n = 130) over 12 years before and after

livestock reduction while accounting for lamb sex and annual environmental variation, including NDVI, precipitation, and winter temperature. With effects of annual

environmental variation removed, livestock reduction increased lamb birth mass by 0.81

kg (95% CI: 0.27 – 1.33 kg), equivalent to an 18% increase in the mean (4.51 kg).

This effect size is substantial, exceeding effects of experimentally imposing

“severe” maternal undernutrition during gestation in domestic sheep Ovis aries (10%

decline in birth mass; Gardner et al. 2007) and matching effects of extreme hardship in

human populations (Siege of Leningrad: 17% decrease in birth mass; Stanner et al. 1997).

My results are similar to effects of intraspecific competition in feral Soay sheep on a

predator-free island, where a 40% decrease in sheep density predicts a ~18% increase in

birth mass (Clutton-Brock et al. 1992).

9

 (Chapters 4 & 5) Does livestock reduction increase argali survival?

Livestock reduction increased survival of argali juveniles, but not adults.

Livestock reduction increased newborn survival during the first 30 days by a raw 22%

(95%CrI: 7.5– 39.3%), increasing from 46% survival pre-reduction to 68% survival post-

reduction in an average NDVI year. Lamb survival over the subsequent 11 months

increased by a raw 34% (95%CrI: 16.0 – 46.9%), from 40% survival pre-reduction to

74% survival post-livestock reduction in an average NDVI year. General linear models

with only 2 explanatory variables – NDVI in May and livestock reduction – explain

97.3% of the cohort variation in newborn survival from 0 to 30 days, and they explain

97.6% of the cohort variation in lamb survival from age 1 month to 12 months. Livestock

reduction did not affect adult survival, which is not surprising given that adult survival

tends to vary less than other vital rates with lower sensitivity (Pfister 1998; Gaillard et al.

1998; Gaillard et al. 2000).

 (Chapter 5) Does livestock reduction increase argali population growth? Which

argali vital rates are most important to population growth?

The large changes in lamb and newborn survival following livestock reduction

also affected population growth, which I estimated using a stochastic population model.

After accounting for NDVI differences pre- and post- livestock reduction, as well as

covariation and cross-correlation between vital rates in a life stage simulation analysis, I estimate that livestock reduction increased argali population growth by 9% per year.

While overall stochastic population growth for the entire duration of my study 2003-2013

10

was λs = 0.96, there was a stark difference before and after livestock reduction.

Accounting for NDVI, population growth changed from pre-reduction λs = 0.91 to post- reduction λs = 1.00. I also found strong signals of bottom-up limitation – with 10% changes in NDVI predicting 2% changes in λs – suggesting that the argali population is susceptible to forage competition from livestock. Adult survival had the strongest effect on population growth, followed by yearling survival, lamb survival, and finally reproductive rate and newborn survival.

 (Chapter 6) What low-cost methods can reliably estimate argali population

growth?

DeCesare et al. (2012) show that population growth (λ) over the prior year can be estimated from adult survival (S) and recruitment (R), by

Equation 1 1

where R is calculated from field collected pre-birth pulse lamb:ewe ratios (X) via

0.5 Equation 2 1 0.5

INNR is the only site where argali survival has been estimated, and it is not reasonable to

assume that adult survival at other sites is similar to INNR. However, it is reasonable to

assume that argali survival at INNR is at a maximum since the population experiences

11

little poaching, persists at high density, and is subject to successful conservation operations; limited empirical evidence from skulls also indicate that adult survival at

INNR is indeed high relative to other locations. The integrated population model from

Chapter 5 estimates that mean survival of adult argali females at INNR is 0.844. Setting S

= 0.844 in Equation 1 intercepts λ = 1 at X* = 0.37. If adult survival is maximized at

INNR, then any argali population requires lamb:ewe ratios of at least 0.37 to be stable; age ratios lower than 0.37 likely indicate a declining population, whereas higher ratios are increasingly likely to indicate positive population growth. My proposed threshold rule of thumb is similar to management recommendations for (Ovis canadensis), whereby populations are considered “non-healthy” if they have consecutive years with lamb:ewe ratios below 0.2 (Western Association of Fish and Wildlife

Agencies 2015).

Collecting data on lamb:ewe ratios requires little training and equipment relative to other methods, and surveys can be conducted on a flexible schedule. For these reasons, age ratio data collection is amenable to involving local communities in participatory monitoring, which has numerous advantages (Singh & Milner-Gulland 2011). Age ratios can provide high-yield information at low cost while opening avenues for engaging local communities in conservation efforts.

RESEARCH SIGNIFICANCE

My dissertation offers empirical evidence that livestock detrimentally affect native ungulates and simultaneously supports a widely employed but rarely evaluated conservation strategy: core zones. Livestock abundance is increasing rapidly in Central

12

Asia, threatening 15 endangered large mammals by increasing conflict and intensifying forage competition (Suryawanshi et al. 2010; Berger et al. 2013; IUCN 2015). However, causality between livestock increases and wildlife declines was recently debated (Berger et al. 2014; von Wehrden et al. 2014). My study, by offering empirical evidence of livestock effects on argali populations, confirms a major threat to biodiversity in the region. At the same time, my study also provides a roadmap for a conservation solution that allows both native biodiversity and indigenous pastoralists to coexist.

CONSERVATION RECOMMENDATIONS

Develop schemes to reduce livestock density and human-wildlife conflict at INNR

The root cause of human-wildlife conflict at Ikh Nart is super-abundant livestock, which negatively affects argali and amplifies conflict with wolves. Yet livestock are key to indigenous livelihoods, creating a conundrum since local pastoralists are crucial allies in conserving biodiversity. There are no clear solutions to this crucible, and the most effective way forward will be to experiment with a variety of interventions aimed both at reducing proximate anthropogenic threats and at reducing livestock density.

Some technical solutions could ameliorate anthropogenic effects on INNR’s wildlife at low cost to pastoralists. Possible solutions include training dogs to not attack argali, and implementing a community insurance scheme for wolf predation on livestock

(Mishra et al. 2003). Alternately, managers could create incentives for pastoralists to reduce livestock herds. However, schemes to reduce livestock density have rarely been implemented in Central Asia. At this stage the most appropriate first step should be to

13

convene a panel of experts who can advise on best practices for designing effective

incentive programs.

Implement and evaluate core zones in protected areas across Central Asia

Core zones – where anthropogenic disturbance is reduced in relatively small areas

of key wildlife habitat inside a larger protected area – are incorporated in many protected

areas. Studies from other sites in Central Asia suggest that core zones might also work in these locations, but these studies have been hampered by poor controls and response variables such as diet and habitat use that have no direct relationship to vital rates or population growth (Suryawanshi et al. 2010; Kaczensky et al. 2011; Li et al. 2014;

Townsend et al. 2014). My dissertation therefore represents the best available evidence,

and that evidence suggests core zones should be implemented – and rigorously evaluated

– in protected areas where livestock are abundant.

Monitor argali populations with age ratios

Methods I develop in Chapter 6 can immediately improve population monitoring wherever argali occur. Data collection on age ratios can occur in tandem with methods to estimate population abundance such as distance sampling, mark-resight, and double observer counts. Monitoring with age ratios complements these population abundance

estimates, adding value at little to cost or disruption to ongoing field projects such as

those in and (Jumabay-Uluu et al. 2014; Valdez et al. 2016).

Estimate survival for other ungulates in Central Asia to enable monitoring with age ratios

14

In principle researchers can monitor all ungulate populations in Central Asia with

age ratios. The limiting factor to adopting this technique is lack of information on adult

survival for most of the region’s ungulate species. Adult survival has been estimated in

six species of Central Asian ungulates, for which age ratios can immediately improve

population monitoring. Telemetry has been conducted on a further 9 ungulates in Central

Asia. For these species research should focus on estimating survival, which would enable

substantially improved population monitoring via age ratios.

DISSERTATION FORMAT

Chapter 2 is “In Press” in Conservation Biology (Ekernas et al. In Press) and is

formatted for publication, but all other chapters are identically formatted. I worked with

collaborators on all chapters, with co-authors listed at the beginning of each chapter, and

for the remainder of the dissertation I switch from “I” to the collective “we.”

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CHAPTER 2

DESERT PASTORALISTS’ POSITIVE AND NEGATIVE EFFECTS

ON RARE WILDLIFE IN THE GOBI

L. STEFAN EKERNAS, University of Montana, Wildlife Biology Program, College of

Forestry and Conservation, Missoula, MT 59812, USA

WESLEY M. SARMENTO, University of Montana, Wildlife Biology Program, College

of Forestry and Conservation, Missoula, MT 59812, USA

HANNAH S. DAVIE, Nottingham Trent University, School of Animal, Rural and

Environmental Sciences, Nottingham NG1 4BU UK

RICHARD P. READING, University of Denver, Department of Biology & Graduate

School of Social Work, Denver, CO 80208 USA

JAMES MURDOCH, University of Vermont, Rubenstein School of Environment and

Natural Resources, Burlington, VT 05405 USA

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GANCHIMEG J. WINGARD, Denver Zoological Foundation, Conservation and

Research Department, Denver, CO 80205 USA

SUKH AMGALANBAATAR, Argali Wildlife Research Center, , Mongolia

JOEL BERGER, Wildlife Conservation Society, Bronx, NY 10460 USA & Colorado

State University, Fisheries, Wildlife, and Conservation Biology, Fort Collins, CO

80523 USA

ABSTRACT

Pastoralists and livestock commonly inhabit protected areas in arid regions of the developing world, resulting in human-wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between native herbivores, carnivores, and pastoralists. To elucidate relationships underpinning human-wildlife conflict, we synthesize 15 years of ecological and ethnographic research from Ikh Nart Nature

Reserve (“Ikh Nart”) in Mongolia’s Gobi steppe. Ikh Nart is a stronghold for wildlife and harbors one of Mongolia’s largest argali (Ovis ammon) populations. Similar to many protected areas in Central Asia, livestock comprise >90% of ungulate biomass and dogs

>90% of large carnivore biomass. Pastoralists exert both bottom-up and top-down forces on argali by decreasing forage availability, increasing mortality from dog predation, and potentially increasing disease risk. Gray wolves (Canis lupus) frequently prey on livestock, which comprise ~90% of diet in some wolves. Wolves annually kill 1-4% of

Ikh Nart’s livestock, and pastoralists kill wolves in retribution. Pastoralists reduce wolf survival but increase recruitment and carrying capacity by providing an abundant food source in livestock. Consequently wolf density is largely decoupled from argali density,

22

and pastoralists have indirect effects on argali that could be negative if pastoralists

increase wolf density (apparent competition) or positive if pastoralists decrease wolf

predation (apparent facilitation). Ikh Nart’s argali population is stable even in the face of

these threats, but livestock are increasingly dominant both numerically and functionally

relative to argali. We offer several solutions to reduce conflict, promote co-existence between pastoralists and wildlife, and simultaneously support pastoralists’ livelihoods.

INTRODUCTION

What happens when protected areas become dominated by livestock? Livestock

commonly range inside protected areas in arid regions of the developing world, including

large parts of Asia and Africa (Du Toit et al. 2010). Pastoralists generally have few

economic opportunities and can most readily enhance their livelihoods by increasing herd

size, resulting in rapid livestock increases over the last 30 years. Livestock now account

for > 90% of ungulate biomass in many protected areas in Central Asia (Berger et al.

2013). Yet these protected areas represent the last strongholds for native vertebrate

herbivores and carnivores. Human-wildlife conflict is inevitable.

At its core, conflict between pastoralists, native herbivores, and carnivores centers

on competition for resources. However, conflicts are multifaceted and involve numerous

direct and indirect pathways. For example, large livestock populations can reduce native

herbivore densities (Madhusudan 2004). Carnivores in turn may selectively target

livestock, which decouples predator-prey dynamics between native species (Novaro et al.

2000). Such changes can lead to unexpected relationships between pastoralists and

wildlife, including indirect positive effects of livestock on native herbivores via

23

reductions in predation (Sundararaj et al. 2012). Alternatively, large livestock populations can lead to increased predator populations and negative effects on native herbivores through apparent competition (DeCesare et al. 2010). Comprehensively understanding human-wildlife conflict therefore requires substantial ecological information on herbivores and carnivores as well as ethnographic information on pastoralists (Figure

2.1). These complementary datasets are rare in Central Asia.

To elucidate ecological relationships underpinning human-wildlife conflict, we present a detailed case study in Mongolia’s Gobi steppe, Ikh Nart Nature Reserve (“Ikh

Nart”). Ikh Nart typifies protected areas in Central Asia in that it is a stronghold for wildlife including argali (Ovis ammon) and gray wolves (Canis lupus) but livestock predominate. Wolves are Near Threatened in Mongolia, with a country-wide population of 10,000 - 62,000 animals and likely declining (Clark et al. 2006; Wingard & Zahler

2006). IUCN classifies argali, the world’s largest sheep, as globally Near Threatened with range-wide population declines (Harris and Reading 2008). Argali are endangered in

Mongolia with a population estimated at 18,000 individuals (Clark et al. 2006; Mallon et al. 2014). Here, we synthesize 15 years of research on ungulates, carnivores, and pastoralists to provide a comprehensive view of human-wildlife conflict at Ikh Nart and illuminate direct and indirect effects of pastoralists on native biodiversity.

METHODS

Study site

Ikh Nart (45.6oN, 108.7oE) encompasses 666 km2 in central Mongolia’s Gobi

steppe (Reading et al. 2011). The climate is harsh, spanning -40o C in winter to +43o C in

24

summer, with ~100 mm of average annual precipitation (Murdoch 2009). Ikh Nart

harbors resident argali and ( sibirica), as well as transient Asian wild ass (Equus hemionus), Goitered (Gazella subgutturosa), and

( gutturosa; Reading et al. 2011). Siberian marmots (Marmota sibirica), formerly common, now occur in small, fragmented colonies due to over-hunting (Clark et al. 2006; Murdoch et al. 2009). Tolai hare (Lepus tolai), Mongolian pika (Ochotona pallasi) and several small rodents and insectivores occur in variable but usually abundant

numbers (Reading et al. 2011).

Native carnivores include gray wolf, corsac (Vulpes corsac), (Vulpes vulpes), (Lynx lynx), manul (Otocolobus manul), Asian badgers (Meles leucurus) and marbled polecat (Vormela peregusna; Reading et al. 2011). Domestic dogs (Canis

lupus familiaris) commonly occur in Ikh Nart, since pastoralists use dogs for herding and

guarding. All these species except polecat kill neonate ungulates (Heptner & Naumov

1998; Murdoch et al. 2010; Murdoch & Buyandelger 2010), but only wolves, dogs, and

potentially lynx kill adult ungulates.

Slightly over 100 semi-nomadic pastoralist families live in and around Ikh Nart, with most families using the reserve only in winter. Pastoralists raise herds of goats

(Capra aegragus), sheep (Ovis aries), horses (Equus ferus caballus), cattle ( taurus), and (Camelus bactrianus), subsist on meat and milk from their animals, and sell meat, hides, and as their primary income (Davie et al. 2014a). Selling crafts to tourists and participating in paid conservation activities – such as repairing wells and assisting with argali captures – provides marginal income (< $200/year) to a minority of families.

25

Argali mortality, abundance, and diet

We have studied argali at Ikh Nart since 1998, including by capturing animals of all age-sex classes and tracking them with telemetry since November 2000 (Kenny et al.

2008; Reading et al. 2009). Denver Zoological Foundation, Argali Wildlife Research

Center, and Mongolian Academy of Sciences conducted captures using methods approved by Mongolian Academy of Sciences. Researchers monitor collared animals two weeks each month, including identifying cause of death by examining carcasses for injuries, body condition, tooth wear, bone marrow, disease, and carnivore signs.

Wingard et al. (2011a) estimated diet overlap between argali and domestic sheep / goats in each season using microhistological fecal analyses. Wingard et al. (2011b) also estimated argali abundance using distance sampling and mark-resight surveys.

Wolf diet

Stable isotope analysis

Davie (2013) estimated wolf diet using δ13C and δ15N stable isotope values from the hair of wolves and several prey species. Prey species were sorted into three isotopically distinct prey groups: sheep and goats; horses; and wild prey, which included argali, ibex, tolai hare, and marmot (Davie 2013; Davie et al. 2014c).

Prey remains at a den

We also measured wolf diet by identifying prey remains at a wolf den that pastoralists identified as being in active use during winter 2010 - 2011 (Ulziiduuren

26

personal communication). In August 2012, L.S.E. and W.M.S. searched a 2x3 m subsection of the cave by digging down to 15 cm and identifying all carcasses based on morphology (which was relatively simple because all carcasses retained skulls). We left the remainder of the cave undisturbed for future investigations. We did not attempt to date carcasses.

Prey remains in dens are often used to investigate carnivore diet, but data are potentially biased because predators do not return all prey to their dens (Palmqvist &

Arribas 2001). Our method underestimated small prey species that wolves consumed whole away from the den; therefore we interpret our results as ungulate selection by a single wolf pack.

Assessing pastoralists’ attitudes towards wolves and argali

Davie et al. (2014a,b) used a semi-structured questionnaire to interview 102 head- of-household pastoralists seasonally inhabiting Ikh Nart – a near census – about herding methods, livestock predation by wolves, attitudes towards wolves, and demographic data.

H.S.D. lived on-site for 15 months while conducting interviews. W.M.S. conducted a second set of interviews in 2012 while living on-site for 12 months (Sarmento & Reading

In Press). W.M.S. and a Mongolian student interviewed 55 head-of-household pastoralists, representing nearly all long-term residents of Ikh Nart, with a structured 22- item questionnaire focusing on attitudes towards argali and conservation.

RESULTS

Domestic and native ungulate populations

27

Interviews indicate a minimum livestock population of 27,620 sheep, 24,790 goats, 2,227 horses, 1,569 cattle, and 434 camels inhabiting Ikh Nart for part of the year

(H.S.D., unpublished data). Mongolia calculates grazing pressure using “sheep units” in which 1 sheep = 1 unit, 1 goat = 0.7 unit, 1 horse = 5 units, 1 cow = 4 units, and 1

= 7 units (Reading et al. 2011). These numbers correspond to livestock stocking density of 99 sheep units per km2, which represents the grazing pressure when all pastoralists are

camped in Ikh Nart simultaneously. After accounting for time pastoralists spend outside

the reserve, we approximate that year-round average livestock density inside Ikh Nart is

25 sheep units per km2.

Distance sampling and mark-resight surveys indicate that 600 argali reside in northern Ikh Nart (95% CI: 200 - 1200; Wingard et al. 2011b). From unsystematic surveys we guess that another 100 - 300 argali inhabit southern Ikh Nart. We lack rigorous estimates for ibex but guess that they number one-third that of argali in the north. Argali weigh about twice as much as sheep, and ibex weigh 1.5 times more than sheep, so we assume 1 argali = 2 sheep units and 1 ibex = 1.5 units (Wingard et al.

2011a). These figures translate total native ungulate density to roughly 2.6 sheep units per km2 (95% CI from argali surveys: 1.0 - 4.8). Stocking densities therefore indicate that

livestock remove 10 times more forage than native ungulates.

Dietary overlap between livestock and argali

Microhistological fecal analysis indicates substantial dietary overlap in key forage

species between argali and livestock: 95% species overlap in spring, 72% in summer,

88% in fall, and 92% in winter (Wingard et al. 2011a). Isotope analysis shows some

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broader differences, with livestock appearing to feed on a higher proportion of C4 plants than argali (Davie 2013; Davie et al. 2014c).

Carnivore populations

Large carnivores

Interviews by H.S.D. yielded a minimum count of 96 dogs at Ikh Nart, but 39% of

interviewees did not respond to questions about dogs. Extrapolating from these data, we

approximate that 200 dogs reside in Ikh Nart for part of the year. Many are untethered for

several hours each day and operate as free-ranging dogs (Davie et al. 2014b).

Wolf density at Ikh Nart is unknown but probably comparable to other areas of

Mongolia. The only site in Mongolia with published estimates of wolf density is a 1200

km2 area centered on Hustai Nuruu National Park with 2 - 3 wolf packs incorporating 20

- 50 wolves (Hovens et al. 2005; Van Duyne et al. 2009). With less than half the

precipitation and concomitantly lower prey density, Ikh Nart might support half that wolf

density. Since Ikh Nart is also half that area, we expect the total wolf population to be ½

density * ½ area ≈ ¼ wolf population of greater Hustai Nuruu NP. We therefore approximate

that Ikh Nart has 1 or 2 wolf packs encompassing 5 - 13 wolves (density = 0.7 - 1.9

wolves per 100 km2), which is consistent with our personal observations of wolf sign and

with reported wolf densities in ecologically similar regions of the former USSR (0.08 -

1.16 wolves per 100 km2; Heptner & Naumov 1998).

Small carnivores

29

Both red fox (density = 0.17/km2) and corsac fox (density = 0.2/km2) are common in Ikh Nart (Murdoch 2009). Densities of other small carnivores – lynx, manul, badger, and polecat – remain unknown. We rarely see but often find spoor of nocturnal badger and manul; lynx appear to be at lower density and are uncommonly, but consistently, reported (M. Lkhavgasuren, personal communication; Reading et al. 2011).

Wolf diet

Stable isotope analysis

Using stable isotope analysis, Davie (2013) found that all sampled wolves (n = 8) preyed on livestock to some extent. Isotope data could not distinguish specific prey species, but livestock contributed between ~10% and ~90% of diet for individual wolves

(Davie 2013).

Prey remains at a den

We located 25 carcasses in a wolf den, yielding species-specific data on prey selection (Table 2.1). Domestic sheep accounted for 21 of the carcasses. We could not positively identify one carcass of a juvenile Capra, which belonged to either an ibex or domestic goat. Livestock therefore accounted for 96 - 100% of ungulate prey. Argali, the most abundant native ungulate, were absent.

Argali mortality causes

We collared and tracked 227 argali from 2000 - 2013 and confirmed 104 mortalities (87 lambs, 7 yearlings, and 8 adults). Predation was the most common cause

30

of mortality for all age classes (Figure 2.2). Dogs or wolves were responsible for 45% of

lamb predation events that we could attribute to a specific carnivore, and predation

caused 48% of lamb mortalities (Table 2.2; Reading et al. 2009). Predation caused 57%

of yearling and 37% of adult mortalities, and only wolves, dogs, and possibly lynx kill

adult/yearling argali. We witnessed dogs killing one collared yearling and one collared

adult argali blind from disease. We also witnessed several other instances (n = 4) of dogs

killing non-collared argali (Young et al. 2011).

Starvation was the second most common mortality cause in all age classes,

causing one-quarter of mortalities among lambs and adults. Disease caused another one-

quarter of mortality in adults but had little effect on other age classes; we recently began

monitoring argali for disease but have not identified any pathogenic agents.

Livestock predation by wolves

In interviews, 31 of 102 pastoralists responded that they had lost livestock to

wolves in the previous year. Pastoralists also provided 44 locations of kill-sites with

physical evidence supporting predation by wolves (Davie et al. 2014a,b). Wolves almost

exclusively killed sheep and goats and rarely killed other livestock. In 2011 - 2012,

wolves predated 4% of livestock in small herds and 1% of animals in larger herds, and

one pastoralist lost 50% of his sheep and goats to wolves (Davie et al. 2014b).

Anthropogenic effects on wolves

Wolf depredation

31

In interviews, 21% of pastoralists at Ikh Nart answered “yes, I hunt wolves”

(Davie et al. 2014b). Direct observation of wolf kills and carcasses confirm that pastoralists kill wolves: in 2012 H.S.D. collected samples from 7 wolf pelts harvested at

Ikh Nart; H.S.D. also observed remains from pastoralists killing several wolf pups and destroying a den in 2013.

Increased prey base

Pastoralists have increased prey availability for wolves by providing a super- abundant food source in livestock. Livestock are subsidized in multiple ways that allow them to attain much higher density than wild ungulates, including provisions of veterinary care, well water, winter fodder, winter shelter, and guard dogs to protect against predators. All wolves we sampled (n = 9) fed on livestock to varying extents.

Increased prey density increases wolf recruitment and carrying capacity (Vucetich &

Peterson 2004), and we expect that livestock positively affect wolves at Ikh Nart (Sharma et al. 2015).

Overall effect on the wolf population

Pastoralists increase wolf recruitment and carrying capacity but simultaneously reduce survival of all wolf age classes. We do not know the overall effect on the wolf population. Indices of wolf abundance (track, sign, and incidental observations) have increased over the last five years, but these indices may not scale linearly with wolf abundance and are unreliable estimators of true population trend.

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Attitudes of pastoralists

Towards wolves

Half of interviewed pastoralists responded that “yes, wolves are a problem at Ikh

Nart” (Davie et al. 2014b). Several pastoralists highlighted the potential severity of wolf

predation events as especially problematic, since wolves kill up to 20 sheep in a single

event. Nonetheless, wolves remain important culturally. Stories told by pastoralists

emphasize that wolves are clever and powerful – traits held in high regard in Mongolian

society – and portray wolves as worthy adversaries rather than villains (Davie et al.

2014b).

Towards argali

Pastoralists voiced overwhelmingly positive attitudes towards argali. Pastoralists

nearly unanimously (96% of n = 55 respondents) answered “Yes, argali can co-exist with

livestock in the same area.” On a 1 - 5 scale, where 1 is unimportant and 5 is very

important, pastoralists ranked protecting argali at 4.8 (SE = 0.07; n = 55). Scoring threats

to argali on the same 1 - 5 scale, pastoralists considered climate change (3.8) and drought

(3.6) the most important threats, mining (3.3) a moderate threat, overgrazing (2.8) and wolves (2.3) low threats, and dogs (1.3) and hunting (1.1) unimportant threats (Sarmento

& Reading In Press).

DISCUSSION

Pastoralists at Ikh Nart exert both positive and negative effects on native wildlife.

Pastoralists kill wolves but simultaneously provide them with an abundant food source in

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livestock. Argali are negatively affected by reduced forage availability, increased

mortality from dogs, and potentially increased disease risk. Pastoralists also have indirect effects on argali mediated by wolves, and these indirect effects may be either positive or negative. Our results embody the central challenge to conservation in Central Asia: how to maintain native biodiversity in the face of overwhelming human presence.

Key points of human-wildlife conflict

Human-wolf conflict

Wolves are a key source of human-wildlife conflict at Ikh Nart, similar to other regions of Mongolia (Kaczensky et al. 2008). Wolves kill livestock, pastoralists kill wolves in retaliation, and both parties are harmed.

Anthropogenic effects on wolves

We lack data to estimate the wolf harvest rate at Ikh Nart, but it may be similar to other protected areas in Mongolia. In Great Gobi B Strictly Protected Area, pastoralists

kill wolves at a rate of 1 wolf per 230 km2 per year (Kaczensky et al. 2008); a similar rate

at Ikh Nart would mean 3.0 wolves killed per year, equivalent to 23 – 60% annual offtake given that we approximate the wolf population at 5-13 animals. In North America harvest

rates of 22% – 48% drive wolf population growth rate to λ ≤ 1 (Creel & Rotella 2010;

Gude et al. 2012). If pastoralists in Ikh Nart kill wolves at the same rate as in other

Mongolian protected areas, pastoralists potentially limit the wolf population.

Anthropogenic effects on native ungulates

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Pastoralists at Ikh Nart affect argali via three primary pathways. One is direct

killing, either by unregulated hunting or dogs. Hunting is well controlled at Ikh Nart, with

no reported poaching event in the last 5 years (Reading et al. 2011; G.W. unpublished

data). However, dogs appear to be a major source of argali mortality (Young et al. 2011).

Dogs outnumber wolves roughly 20:1; we have observed dogs killing argali adults and lambs; and predation is the leading cause of mortality for all age classes.

Second, livestock likely impose forage competition on argali. At Ikh Nart argali and livestock have a high degree of diet overlap, livestock range throughout the reserve, and livestock remove roughly ten times more forage than argali. Argali are also sensitive to forage availability: starvation is the second-most common mortality cause in all age classes, and year-to-year variation in birth mass, lamb survival, and asymptotic population growth closely track vegetation greenness (Chapters 3-5). Most convincingly, pseudo-experimental livestock reduction in a 71 km2 area of key habitat positively affected argali, strongly increasing lamb birth mass, survival, and population growth over a 12-year period (Chapters 3-5).

Third, disease transmission from livestock may negatively affect argali. Disease accounted for 25% of mortalities among collared adult argali, which is probably an underestimate because field identification of diseases is difficult. We have observed diseased animals go blind and walk in circles prior to dying, and we find bodies of dead animals that seem otherwise healthy. Whether argali diseases originate from livestock is unknown, but disease transmission from domestic to wild sheep is common in North

America

(Smith et al. 2014).

35

Pastoralists impose both top-down (e.g. predation) and bottom-up forces (e.g. food limitation) on argali, even without poaching. This renders some otherwise important questions less relevant. For example, determining whether dog predation mortality is

additive or compensatory does not change how we attribute anthropogenic mortality;

argali killed by dogs may be part of the ‘doomed surplus’ that would have died from food

shortages resulting from livestock grazing (Errington 1945), but anthropogenic factors

caused mortality either way. Furthermore, top-down and bottom-up forces can interact to

create much stronger population effects than either factor in isolation (Krebs et al. 1995).

If Ikh Nart’s argali population is indeed suppressed by the interaction of bottom-up and

top-down anthropogenic forces, then removing one forcing factor – such as dog predation

– can have unexpectedly large positive effects.

Indirect effects

Predator-prey dynamics between wolves and argali have been largely severed at

Ikh Nart. Pastoralists may suppress the wolf population through excessive harvest, or

they may increase wolf density by providing an abundant food supply in livestock. Either way, argali play only a secondary role. At first glance, pastoralists’ overall effect on

wolves appears to be dichotomously a conservation success (stable wolf population) or

failure (wolf population declining and threatened with extirpation). However, both of

these outcomes are rendered into partial conservation successes when we account for

pastoralists’ indirect effect on argali as mediated by wolves.

Apparent competition: wolves prosper, argali suffer

36

When human activity increases a native or exotic ungulate, predator populations

can increase due to increased food supply and thereby increase predation on rare

ungulates via apparent competition (DeCesare et al. 2010). If the overall effect of

pastoralists is to increase wolf abundance, then argali likely suffer from increased wolf

predation. A stable wolf population has many positive conservation aspects, but it puts

additional pressure on Ikh Nart’s argali population. Pastoralists negatively affect argali by

increasing exotic predators (dogs), decreasing food supply, and potentially increasing

disease risk. We do not know whether an increase in wolves would cause argali to

decline, but it is a possibility.

Apparent facilitation: wolves suffer, argali prosper

Alternately, pastoralists may exert positive indirect effects on argali by reducing

wolf predation. If pastoralists suppress wolf density through harvest, then native

ungulates benefit from decreased wolf predation (Leopold 1943). Sundararaj et al. (2012) recognized that a second mechanism can cause apparent facilitation: prey switching, whereby carnivores prey on livestock instead of native ungulates. At Ikh Nart some wolves preferentially select livestock over native ungulates, since livestock constituted 96

- 100% of ungulate prey in the one wolf pack for which we have species-specific data.

Extrapolating from a single wolf pack is fraught with uncertainty, but isotope data from n

= 8 wolves confirm that livestock comprise a majority of diet in some wolves. These

results, coupled with the real possibility that pastoralists suppress wolf density through

excessive harvest, show the potential for pastoralists to have indirect positive effects on

argali.

37

Solutions to reduce human-wildlife conflict

The fundamental cause of human-wildlife conflict at Ikh Nart is super-abundant livestock, which negatively affects both wild ungulates and carnivores. Several solutions can reduce proximate anthropogenic threats to wildlife with little or no cost to pastoralists, but they fail to address the root cause of conflict. Alternately, conservationists can aim to reduce livestock by creating incentives that exceed pastoralists’ losses in income, food, and raw material.

Create incentives to reduce livestock density

Two potential schemes can incentivize pastoralists to reduce livestock numbers.

First is green labeling, whereby consumers pay a higher price for products certified as having been produced using ecologically responsible methods. Implementing green labeling is difficult, since it requires developing a non-leaky supply chain and label- certification process, implementing a sophisticated marketing program to identify and inform potential consumers in international markets, and finding international distributors

(Piotrowski & Kratz 2005). A second, simpler, method is to improve access to markets and veterinary care in exchange for reduced livestock numbers. In remote areas, transportation costs to get animal products to distant markets can be substantial and few veterinarians are available. If conservation groups assume these transportation and veterinary costs, they could increase pastoralists’ profit margins and productivity and thus allow pastoralists to reduce livestock herds without foregoing income.

38

Reduce negative effects on wild ungulates

Spatially reconfiguring livestock away from key wildlife habitat can reduce negative effects on biodiversity without reducing overall livestock density. In 2006, Ikh

Nart’s Director (S.A.) worked with pastoralists to reduce human and livestock density by

40% inside a 71 km2 core zone of key argali habitat. The core zone effectively functions as a grass bank and blends ecological knowledge about argali with traditional semi- nomadic herding practices that emphasize movement and maintaining forage reservoirs

(Davie et al. 2014b). Livestock reduction in the core zone positively affected argali, increasing lamb birth mass by 18%, increasing juvenile survival from pre-reduction 19% to post-reduction 51%, and increasing argali population growth rate by 9% annually

(Chapter 5). However, the core zone is less effective for species with different habitat preferences (Murdoch et al. 2014).

We can also reduce dog predation on argali. Dogs serve an important household role in guarding livestock and property (Davie et al. 2014b), meaning that we cannot reduce dog density by asking pastoralists to give up their animals. However, dogs are trained to not hurt livestock, so training to not harass argali should be possible. Many pastoralists recognize that their dog kill argali, but do not realize the scope of the problem

(Sarmento & Reading In Press). We have begun educating pastoralists about the dangers dogs pose to argali, and requesting that they take steps to reduce that threat. Most pastoralists are willing to train their dogs to stop attacking argali; some have even given us permission to kill their dogs if we observe them killing argali, although that is a tactic we avoid for many reasons. Effective dog-training programs have the potential to strongly reduce dog predation on argali at little cost to pastoralists.

39

Increase Ikh Nart’s protected area status

An alternate solution is to prohibit or restrict livestock numbers in all of Ikh Nart, either through local government (soum) regulations or by uplisting Ikh Nart’s protected area status. Costs to local communities would be high, as pastoralists would lose access to Ikh Nart’s 666 km2 of grazing lands. Species ranging mostly within Ikh Nart would

presumably benefit, but effects on wide-ranging species – such as wolves, Asiatic wild

ass, and Mongolian gazelle – are less clear. Benefits to wildlife from removing livestock need to be carefully weighed against the costs to pastoralists, who need to be integrated in the decision making process.

Reduce human-wolf conflict

Two solutions could reduce human-wolf conflict in Ikh Nart and more broadly in

Mongolia. First, conflict in Ikh Nart is well-suited to a community insurance program.

Currently each individual herder faces the risk of ruinous losses (such as losing 50% of livestock) even though losses to the whole community are manageable (1 - 4% losses).

Community insurance could increase pastoralists’ financial stability and decrease individual risk, and it could thereby facilitate increased tolerance for wolves (Mishra et al. 2003).

Second, and broadly applicable to most of Mongolia, is to restore populations of wild prey favored by wolves: marmots and red ( elaphus). Overharvest has reduced Mongolia’s population by 92% since 1990 (Clark et al. 2006) and reduced Mongolia’s marmot population by 85% since 1940, with the most dramatic

40

declines occurring after 1990 (Murdoch et al. 2009). Wolves select both red deer and marmots out of proportion to their availability vis-à-vis livestock (Hovens et al. 2005;

Van Duyne et al. 2009). We recommend investigating the costs and benefits of restoring marmot and red deer populations to hotspots of human-wolf conflict in Mongolia.

Addressing pastoralists’ perception of human-wolf conflict is equally important as reducing economic harm from wolves. Attitudes and assumptions about conflict influence quantified estimates of wildlife damage, shape how people interpret that damage’s severity, and affect the intensity of responses (Dickman 2010). Denver

Zoological Foundation has, for over a decade, conducted community outreach and education targeting biodiversity conservation at Ikh Nart (Reading et al. 2011). Similar efforts should be integral to human-wolf conflict mitigation schemes.

Conclusion

Human-wildlife conflict poses a serious challenge to biodiversity conservation in

Central Asia, where many protected areas are dominated by pastoralists and their livestock. Conflict harms wildlife populations, undermines livelihoods, and erodes support for conservation. Conversely, communities that are vested in conflict resolution schemes can be powerful allies (Hazzah et al. 2014). Pastoralists at Ikh Nart strongly support argali conservation, which is partly a result of long-term community outreach.

The core zone in Ikh Nart has successfully alleviated some of the grazing competition imposed by livestock, and argali population growth is positive (Chapter 5). Nonetheless, rapidly increasing livestock threaten to overwhelm native ungulates’ functional role; argali’s small biomass relative to introduced ungulates (< 10%) and small contribution to

41

carnivore diet (< 10% for some wolves) are similar to areas of Patagonia where native

ungulates have been declared functionally extinct (Novaro et al. 2000). Low wolf density

coupled with diets focused on livestock means that wolves appear to have little effect on

the argali population, and dogs have replaced wolves as the functionally dominant large

carnivore. The root cause of these perturbations is high livestock density, which threatens

wildlife populations through a variety of direct and indirect pathways. The central challenge facing conservation in Ikh Nart and the rest of Central Asia is how well these

threats can be managed to allow both native biodiversity and indigenous pastoralists to

thrive.

ACKNOWLEDGMENTS

This work was supported by Denver Zoological Foundation, University of Montana,

University of Vermont, Wildlife Conservation Society, Argali Wildlife Research Center,

Earthwatch Institute, National Geographic Society (grant C201-11), the American Center

for Mongolian Studies under the US-Mongolia Field Research Fellowship Program, and

the National Science Foundation (grant DGE-0504628). We thank T. Selenge and S.

Batdorj for logistical support, Ulziiduuren for initially showing us a wolf den and

detailing his observations of wolf activity there, and numerous field assistants and

Earthwatch volunteers for their work collecting data. S. Mills, J. Maron, L. Samberg, and

T. Laverty greatly improved the manuscript with insightful comments.

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populations. BioScience 61: 125-132.

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Table 2.1 Prey remains at a wolf den in Ikh Nart Nature Reserve, Mongolia. Biomass of sheep and goats = 35 kg, Siberian marmot = 7 kg.

Species # Carcasses % of biomass

Sheep 21 87

Goat 2 8

Goat or Ibex 1 4

Siberian marmot 1 < 1

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Table 2.2 Cause-specific predation of VHF/GPS collared argali at Ikh Nart Nature

Reserve, Mongolia, from 2001-2013.

Carnivore Lambs: Adults + yearlings:

# predated % of total # predated % of total

Unknown 24 - 5 -

Dog 2 11 1 50

Wolf 1 6 0 0

Wolf or Dog 5 28 1 50

Fox 3 17 0 0

Raptor 1 6 0 0 Manul 6 33 0 0

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Figure 2.1 In grazing systems where biomass (indicated by oval size) is dominated by pastoralists and their livestock and dogs, wildlife interactions with pastoralists often intensify (bold arrows) while other interactions weaken (dotted arrows). Mechanisms through which pastoralists, native herbivores, and carnivores affect each other are listed next to arrows.

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Figure 2.2 Cause of death for VHF/GPS collared argali at Ikh Nart, 2001-2013.

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CHAPTER 3

EVALUATING CORE ZONES IN ARID PROTECTED AREAS:

ARGALI IN THE GOBI STEPPE

L. STEFAN EKERNAS, University of Montana, Wildlife Biology Program, College of

Forestry and Conservation, Missoula, MT 59812, USA

RICHARD P. READING, University of Denver, Department of Biology & Graduate

School of Social Work, Denver, CO 80208 USA

GANCHIMEG J. WINGARD, Denver Zoological Foundation, Conservation and

Research Department, Denver, CO 80205 USA

SUKH AMGALANBAATAR, Argali Wildlife Research Center, Ulaanbaatar, Mongolia

DAVID KENNY, Raptors Botswana, Maun, Botswana

JOEL BERGER, Wildlife Conservation Society, Bronx, NY 10460 USA & Colorado

State University, Fisheries, Wildlife, and Conservation Biology, Fort Collins, CO

80523 USA

ABSTRACT

Like national parks, core zones are frequently assumed to effectively protect populations,

yet this assumption has rarely been tested. In Central Asia, a major challenge to

conservation is that many endemic large mammals have vast home ranges that exceed

boundaries of protected areas. Increases in livestock densities aggravate the issue because

conflicts between pastoralists and native species increase, yet livestock are both

ubiquitous in Central Asia’s protected areas and critical to indigenous livelihoods. Core

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zones, which reduce anthropogenic disturbance in relatively small areas of key wildlife

habitat, present one potential solution for advancing conservation while supporting

traditional livelihoods. However, rigorous tests of core zones’ efficacy are rare. Here we utilize a before-after treatment spanning 12 years in Mongolia’s Gobi steppe to measure

effects on argali (Ovis ammon) of reducing human and livestock densities by 40% inside

a 71 km2 core zone of key habitat representing 18-60% of adult argali home ranges. We

focus on argali birth mass, which we expect to both have important fitness consequences and be sensitive to forage competition from livestock. Accounting for inter-year environmental variation (NDVI, precipitation, winter temperature, and core zone

treatment) and individual variables (sex, birthdate, and age at capture), we found that

livestock reduction increased argali birth mass by 0.81 kg (95% CI: 0.28 – 1.33 kg; n =

130), equivalent to an 18% increase from the mean. Our study provides empirical

evidence that reducing anthropogenic disturbance from small but biologically important

habitat can positively affect large mammals, and supports core zones as an effective

management strategy in the region.

INTRODUCTION

Central Asia harbors an impressive array of wildlife that includes at least 39

species of native ungulates and carnivores (Schaller 1998; Clark 2006; Wingard & Zahler

2006). Many are threatened by over-hunting and high livestock densities (Milner-Gulland

et al. 2003; Bhatnagar et al. 2007; Berger et al. 2013). Exacerbating these threats, wild

ungulates have large home ranges that often exceed boundaries of protected areas

(Kaczensky et al. 2011; Fleming et al. 2014). Livestock numbers in the region are

54

increasing rapidly, and high livestock density is frequently cited as a primary driver of

wildlife population declines in the region (Bagchi et al. 2004; Mishra et al. 2004; Berger

et al. 2013). Core zones, in which livestock densities and other anthropogenic disturbances are reduced inside relatively small areas, have been posited as a solution to allow wildlife to co-exist with pastoral communities (Mishra et al. 2010). Several countries in Central Asia have adopted core zones inside protected areas with abundant

livestock (e.g. Kaczensky et al. 2011; Li et al. 2014), yet core zones’ efficacy in

positively influencing wildlife – particularly large mammals – has rarely been rigorously

evaluated.

Protected areas in Central Asia often do not encompass ungulate home ranges that

are as large as 90,000 km2 (Mongolian gazelle Procapra gutturosa: Fleming et al. 2014)

or 70,000 km2 (Asiatic wild ass Equus hemionus: Kaczensky et al. 2011). Even when it is possible to design protected areas around home ranges of a target species, legislation in

Central Asia typically allows for livestock grazing and human settlements inside protected areas. An attractive approach within these constraints is to minimize livestock in core zones of key wildlife habitat, which are much smaller than target species home ranges (Mishra et al. 2010). Many protected areas in southern and East Africa are functionally similar in that they encompass only a small portion of migratory ungulates’ home ranges, usually dry season ranges while wet season ranges are not protected (or vice versa; Western et al. 2009; Fynn & Bonyongo 2011).

Little is known about core zones’ effects on wildlife. Core zones are clearly insufficient when development – such as fences, agriculture, or energy production –

severs migratory routes or degrades unprotected habitat (Bolger et al. 2008; Beckmann et

55

al. 2012; Ogutu et al. 2013; Ekernas & Berger 2016). Seasonally migratory ungulates in southern and East Africa as well as North America have been particularly affected by such development (Berger 2004; Harris et al. 2009; Fynn & Bonyongo 2011). But in

Central Asia landscapes are more intact because fences and crop agriculture are sparse, and less is known about the efficacy of core zones in this context. Most studies that have evaluated core zones are poorly controlled, which undermines our ability to attribute between-site differences to management practices rather than habitat differences (Table

3.1). Furthermore, many studies from Central Asia have relied on metrics (e.g. habitat selection or diet) that have no clear relationship to fitness, vital rates, or population viability.

Here, we use a before-after treatment spanning 12 years in Mongolia’s Gobi desert-steppe to investigate the effects of reducing livestock inside a core zone on argali

(Ovis ammon) at Ikh Nart Nature Reserve (INNR; Figure 3.1). We focus on lamb birth mass, which is both sensitive to competition and has important fitness consequences

(Fairbanks 1993; Jones et al. 2005; Griffin et al. 2011). Reproductive effort is one of the first vital rates to change in response to intraspecific competition (Gaillard et al. 1998,

2000; Eberhardt 2002; Martin & Festa-Bianchet 2010), and we therefore expect lamb birth mass to be sensitive to interspecific competition. Birth mass also has important fitness consequences. Low birth mass is associated with lower survival in several temperate ungulates (domestic sheep Ovis aries: Clutton-Brock et al. 1992, Jones et al.

2005; Antilocapra americana: Fairbanks 1993; Elk Cervus elaphus: Singer et al. 1997, Griffin et al. 2011). In addition, birth mass predicts adult body mass and size – important factors in male reproductive success – among bighorn sheep rams (Ovis

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canadensis) when population density is high (Festa-Bianchet et al. 2000). More detailed information on fitness consequences comes from humans and domestic animals, where low birth mass resulting from maternal undernutrition is associated with increased risk for a host of cardiovascular, pulmonary, psychological, and metabolic diseases, with some risks passed on to offspring (Greenwood & Bell 2003; Funston et al. 2010;

Roseboom et al. 2011). Since lamb birth mass is both sensitive to forage competition and has important fitness consequences, it is an excellent response variable for investigating core zone effects on wild ungulates.

METHODS

Study site

We studied argali at INNR (45.6oN, 108.7oE), which encompasses ~660 km2 in

central Mongolia’s Gobi desert-steppe (Reading et al. 2011). Temperatures span from -

40o C in winter to +43o C in summer, with ~100 mm average annual precipitation (Airag,

Bayanjargalan, and Choyr weather stations, 2014). Most precipitation occurs in the

summer months of June-August, with small amounts of snow accruing in winter (max

snow depth < 10 cm in most years).

INNR harbors roughly 800 argali, which represents one of the largest argali

populations in Mongolia (Wingard et al. 2011b; Reading et al. 2011). Argali have been

studied intensively at INNR since 2000 (Reading et al. 2005), and in 2009 the United

Nations Development Programme recognized INNR as a model Mongolian protected

area for its effective and collaborative management.

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Slightly over 100 semi-nomadic pastoralist families use INNR on a permanent or seasonal basis, setting ger camps and herding flocks of goats, sheep (Ovis aries), horses

(Equus ferus caballus), cattle (Bos taurus), and camels (Camelus bactrianus; Davie et al.

2014). Interviews conducted in 2012 provided minimum counts of 27,620 sheep, 24,790 goats, 2,227 horses, 1,569 cattle, and 434 camels inhabiting Ikh Nart for parts of the year

(Davie unpublished data). Livestock therefore vastly outnumber argali at INNR and consume roughly 10 times more forage (Wingard et al. 2011a; Chapter 2). Most pastoralist families also keep herding dogs, which are free-roaming for several hours each day and have been observed to attack and kill both adult and juvenile argali (Young et al.

2011; Davie et al. 2014).

Livestock manipulation

In 2006, INNR’s manager (S.A.) reduced human and livestock density inside a 71 km2 core zone of key argali habitat within INNR following the voluntary departure of three pastoralist families and their 500 livestock. Two families and their 700 livestock remained, and a ranger without livestock moved in. The net effect was that both human and livestock density were decreased by 40% inside the core zone (Figure 3.1). We emphasize that INNR’s total livestock, dog, and pastoralist populations were unchanged by core zone implementation; only their spatial distributions were altered to reduce their density inside the core zone.

The core zone contains key argali habitat, but represents only a small portion of argali home ranges. The core zone was delineated from surveys that found high argali densities in the area plus data on VHF-collared argali which showed that animals

58

consistently used the area (Reading et al. 2005). However, the core zone is relatively

small and covers only 18-60% of home ranges from GPS-collared adult argali (n = 9

individuals), representing approximately 25% of total occupied argali habitat at INNR.

Although we sampled lambs both inside and outside the core zone, we expect that

all mothers of sampled lambs utilized the core zone: all lambs were captured within 6 km

of the core zone, which is a relatively short distance for adult argali to traverse (Figure

3.2). We therefore lack data from a control site where livestock density was not

manipulated, and our dataset follows a simple before-after study design for livestock

reduction. Consequently we rely on climate and environmental covariates to account for

inter-year variation, and livestock reduction is one of several fixed environmental

variables – in addition to individual lamb variables such as sex and birthdate – we use to

predict lamb birth mass.

The response variable: lamb birth mass

We sampled argali lamb birth mass by capturing and weighing argali lambs at

INNR from 2003-2013 (Kenny et al. 2008; Reading et al. 2009). During the lambing

season researchers searched on foot for adult females, closely observed adults for

behavioral and morphological signs of having a neonate, and then searched areas around target females for neonate lambs. Newborn lambs were captured by hand, which is possible during the first days after birth while lambs still lie in hiding (Kenny et al. 2008).

Upon capture, lambs were weighed, measured for various morphological features such as body length and neck girth, sexed, aged to the nearest day based on morphology and behavior, fitted with a VHF collar, released, and subsequently tracked (Reading et al.

59

2009). We weighed lambs by placing them in a cloth bag attached to a hanging scale, and

measured weight to the nearest 0.1 kg. To reduce stress and disturbance, we minimized

handling times (mean handling time = 11.7 minutes) and immediately departed the

capture area after release. These data incorporate a before-after treatment for livestock

reduction in the core zone: lambs born in years 2003-2006 experienced prenatal

conditions at higher livestock densities in the core zone, whereas lambs born in 2007-

2013 experienced lower livestock densities in the core zone.

Captures took place during the peak lambing season in April, with the earliest

captures occurring in late March and the latest in early May. Capture dates roughly

matched the lambing season in a given year, but did not necessarily represent the full

range or distribution of lamb birth dates. Captures were conducted by Denver Zoo,

Mongolian Academy of Sciences, and National University of Mongolia, with permits and methods approved by Mongolian Academy of Sciences.

Individual covariates: sex, Julian birthday, and age at capture

During captures we recorded the sex and estimated age in days for each lamb. We

then calculated each individual’s birthdate based on our age estimate. Ovis lamb weights

are associated with all three of these factors (Clutton-Brock et al. 1992), and we include

them as fixed effects in our analysis.

We did not know the identity or reproductive history of mothers for the vast

majority of captured lambs. Maternal body condition, age, and reproductive history affect

Ovis lamb birth weights (Clutton-Brock et al. 1992; Festa-Bianchet & Jorgenson 1998).

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Maternal effects therefore caused variation to lamb birth weights that we were unable to account for, weakening our power to detect environmental and individual effects.

Environmental covariates: NDVI, precipitation, and winter temperature

In the Gobi desert, forage availability for ungulates is closely linked to precipitation and Normalized Differential Vegetation Index (NDVI; Berger et al. 2013).

We obtained NDVI readings for the years 2002-2013 (NASA Land Processes Distributed

Active Archive Center, MOD13Q1 data). NDVI readings were averaged inside two areas using QGIS (Quantum GIS Development Team 2014): all of INNR (660 km2), and the

smaller core zone (71 km2). For each of these two areas we focused on two specific

NDVI readings. First we used the NDVI reading from May 9 of each year, which is the

earliest date that NDVI detects green-up at INNR. Winters at INNR are long and harsh,

and spring represents the most difficult time of year for ungulates (Begzsuren et al.

2004). NDVI on May 9 therefore measures forage availability during a critical time of

year. Second, we measured integrated NDVI over the whole year, which represents

cumulative plant growth over the entire growing season, by calculating area under the

curve with NDVI value of 0.125 set as a floor; NDVI values over 0.1 can indicate green

forage availability in the Mongolian Gobi (Leisher et al. 2012), but ground-truthing

vegetation at our study site indicates that 0.125 is a more accurate minimum NDVI value

for green-up. NDVI readings from the core zone and all of INNR were strongly

correlated (May 9 NDVI r2 = 0.94; yearly integrated NDVI r2 = 0.83), and in our analyses we use NDVI values from only the core zone since all argali we have fitted with

61

GPS collars use the core zone whereas other sections of INNR are only used by some

individuals.

The closest weather station is located 45 km east of INNR in the town of Airag,

which has similar elevation and vegetation to INNR. We used daily readings of

precipitation as well as minimum and maximum temperature at the Airag weather station

from 2002-2013. Because severe winter temperatures are associated with lower birth

weights in Mongolian gazelle (Olson et al. 2005), we measured winter severity by

calculating the mean daily minimum temperature from December 1 – March 15. We

measured April precipitation by summing daily precipitation from April 1 to April 30,

and measured yearly precipitation by summing daily precipitation from January 1 –

December 31.

Summer forage availability potentially affects mass of lambs born in spring, but

with a one year lag time. Indeed at our study site argali lamb survival in the first month is

higher in years with increased precipitation during the prior April (Reading et al. 2009).

In our models we therefore include NDVI and precipitation values from the prior year.

Population density can affect birth mass of Ovis lambs (Clutton-Brock et al.

1992), but we lack precise year-to-year measurements of argali density and therefore do not include it in our analysis. In our surveys we have not observed large fluctuations in argali density or adult mortality, and we suspect density has remained fairly constant

year-to-year though gradual changes probably occurred.

Statistical analysis

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We used general linear models to predict lamb birth weight from individual (sex,

Julian birthday, and age at capture) and environmental explanatory variables (livestock

before/after, integrated NDVI, May NDVI, yearly precipitation, April precipitation, and

mean winter temperature). All explanatory variables were treated as fixed effects. We

chose candidate models a priori to the analysis and compared them using AICc, with

analyses performed in program R (R Development core team 2014).

RESULTS

Lamb birth mass

We obtained birth weights from n = 130 argali lambs born over 11 years spanning

2003-2013. Lambs were all less than 7 days old at capture, and average age at capture

was 1.5 days. Mean birth weight was 4.5 kg with a standard deviation of 1.06 kg (range:

2.3 – 8.2 kg).

Factors predicting lamb mass

Lamb birth mass was positively associated with precipitation and NDVI from the

prior year, and birth mass was significantly higher after livestock reduction (Figure 3.3).

Reduced livestock density in the core zone predicted lamb birth mass to increase by 0.81

kg (model weighted average; 95% CI: 0.28 – 1.33 kg), equivalent to an 18% increase

from the mean. Models that included livestock reduction as an explanatory variable

carried >99% of Akaike weight, and the top two AICc models had virtually no support

without livestock reduction as an explanatory variable (Table 3.2). Male lambs were

heavier than females by 0.37 kg (model weighted average; 95% CI: 0.05 – 0.69 kg). We

63

found little support for Julian birthday, average winter temperature during gestation, or

estimated age at capture predicting lamb birth mass.

DISCUSSION

We evaluated the effects on argali of reducing livestock density inside a core zone

at INNR with a before-after treatment, while accounting for inter-year climatic variation.

Reducing livestock and human density in the relatively small core zone increased argali

lamb birth mass by 0.81 kg, an 18% increase from the mean. Our results provide some of

the strongest evidence to date that core zones can be an effective management strategy for reducing detrimental effects of livestock on native ungulates.

Core zones have great potential for improving conservation in Central Asia because they represent a practical solution that combines ecological knowledge with traditional herding practices (Mishra et al. 2010). In Mongolia, semi-nomadic pastoralists move seasonally to maintain forage reservoirs that can be used later in the year (Bedunah

& Schmidt 2004; Davie et al. 2014). The core zone at INNR is similar in that it functions as a grass bank of reserve forage that pastoralists can use during droughts. The core zone therefore does not represent a complete loss in grazing lands for local pastoralists, but instead functions as a type of insurance that melds with traditional herding practices.

These features made pastoralists more receptive to setting aside a core zone. However, the endeavor was only possible because INNR’s director (S.A.) spent more than a decade building local relationships and collecting biological that demonstrated the importance of the area to argali. Long-term commitment to specific sites and communities can be critical to conservation success (Wyborn & Bixler 2013).

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Reducing livestock density in the core zone increased lamb birth mass by 18%

from the mean, which is substantial when compared to results from studies of other

species. In domestic sheep with similar mean birth mass as argali (4.7 kg compared to 4.5

kg for argali), experiments restricting maternal food intake indicate that “severe”

undernutrition is required to reduce birth mass by 0.5 kg (Gardner et al. 2007). Among

Soya sheep living on a predator-free island, birth weights decrease linearly with increasing population density and an 18% decline in birth weight is predicted with a

~40% increase in Soya sheep population density (Clutton-Brock et al. 1992). In human populations, only extreme hardship reduces birth weights to a similar degree as we observed for argali (Dutch famine: 7% reduction in birth weight, Painter et al. 2006;

Siege of Leningrad: 17% reduction in birth weight, Stanner et al. 1997). These comparisons suggest that an 18% change in birth mass is biologically significant and that livestock grazing has detrimental effects on argali.

Asking marginalized pastoralists to change their herding practices for the sake of wildlife requires strong evidence that livestock negatively affect wildlife (von Wehrden et al. 2014). Our study indicates that livestock impose forage competition on argali.

Livestock greatly outnumber argali at INNR and remove an order of magnitude more forage than argali (Wingard et al. 2011b). Dietary overlap between argali and livestock is also high, reaching 95% during the most critical time of year, spring (Wingard et al.

2011b). We found that argali lamb birth mass closely associates with NDVI and precipitation, which suggests that the argali population is bottom-up limited and susceptible to forage competition from livestock. Most convincingly, reducing livestock in the core zone increased argali birth mass, and altered forage availability is likely the

65

mechanism explaining livestock-associated changes in argali birth mass. Our study therefore supports the hypothesis that livestock, particularly domestic goats and sheep, impose forage competition on argali. Since goats and sheep are rapidly increasing throughout Central Asia, our results portend continuing declines in the region’s wildlife populations (Berger et al. 2013).

At the same time, we find reason for optimism in our results. Conservationists need to identify management solutions that don’t push pastoralists into more destructive livelihoods such as mining (von Wehrden et al. 2014; Berger et al. 2014), and managers at INNR increased argali birth mass without reducing pastoralists’ herd sizes. The core zone draws on traditional herding practices and now effectively functions as a grass bank

– a reservoir of forage that pastoralists can draw upon in case of drought. We believe

INNR’s core zone management strategy provides a model to maintain indigenous livelihoods and biodiversity that should be emulated and evaluated in other protected areas.

ACKNOWLEDGEMENTS

We are deeply grateful to the numerous field staff who assisted with capturing argali lambs. We thank T. Selenge for obtaining climate data and providing logistical support; B. Rosenbaum for graciously sharing movement data from GPS-collared argali;

H. Davie for providing data on livestock numbers at INNR; and W. Sarmento for the argali resource selection analysis. T. Laverty and W. Sarmento improved the manuscript with excellent comments. This work was supported by Denver Zoological Foundation,

University of Montana, Wildlife Conservation Society, Colorado State University, Argali

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Wildlife Research Center, Earthwatch Institute, and the National Science Foundation

(grant DGE-0504628).

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Table 3.1 Studies evaluating effects of core zones on wildlife populations in arid regions where the core zone represents only a fraction of target species’ home ranges. We exclude fully fenced reserves that historically had migratory populations that ranged outside the reserve but now only harbor animals whose movements are curtailed to inside the protected area. Migratory populations from Africa and North America are placed at the bottom of the table; populations in the top section are nomadic or sedentary populations in Central Asia (following definitions in Olson et al. 2010).

Site Country Core zone Core zone Portion of Response variable Species Key result Control? Ref size, km2 regulations home range Great Gobi B SPA Mongolia 1800 NS NL Large Habitat selection Equus hemonius Some use None 1

Edge Habitat selection Equus ferus przewalski Some use None

Myangan Ugalzat NP Mongolia 122 NS NL* Variable Occupancy Multiple Different spp in Cross-site 2

core vs buffer comparisonU

Hustai NP Mongolia 500 NS NL Large Pellet density Cervus elaphus ↑ Pellet density Cross-site 3

comparisonU

Sanjiangyuan NR 31,218 NS NL Small Habitat selection Panthera uncia Little use None 4

Spiti: Kibber WS 20 NL Small Young:female ratio Pseudois nayaur ↑ Recruitment Cross-site 5

Gramindoids in diet ↑ Graminoids comparisonU

Spiti India 5 NL Small Habitat selection Pseudois nayaur ↑ Use Before-after 6

Spiti India 14 RL Small Young:female ratio Pseudois nayaur ↑ Recruitment Cross-site 7

Density ↑ Density comparisonU

Graminoid biomass ↑ Gram. biomass

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Site Country Core zone Core zone Portion of Response variable Species Key result Control? Ref size, km2 regulations home range Nairobi NP Kenya 117 NS NL Dry season Abundance Migratory ungulates ↓ Abund. over time None 8, 9

Amboseli NP Kenya 392 NS NL Dry season Abundance Migratory ungulates ↓ Abund. over time None 8, 10

Tarangire NP Tanzania 2850 NS NL Dry season Abundance Migratory ungulates ↓ Abund. over time None 11

Central Kalahari GR Botswana 52,800 NS NL Wet years Abundance Connochaetes taurinus ↓ Abund. over time None 12

Grand Teton NP USA 1254 NS NL Summer Habitat availability Antilocapra americana ↓ Winter habitat ↑ Disturbance 13

Yellowstone NP USA 718 NS NL Summer Recruitment Cervus elaphus ↓ Recruitment ↑ Predators/ drought 14

+ control site

SPA = Strictly Protected Area NP = National Park NR = Nature Reserve WS = Wildlife Sanctuary GR = Reserve

NS = No settlements NL = No livestock RL = Reduced livestock *Not enforced; livestock and people present

Cross-site comparisonU = Uncontrolled comparison between two sites; lacks before-after treatment, replication, or other form of control

1 Kaczensky et al. 2008 2 Townsend et al. 2014 3 Thapaliya 2008 4 Li et al. 2014 5 Suryawanshi et al. 2010

6 Mishra et al. 2003 7 Mishra et al. 2004 8 Western et al. 2009 9 Ogutu et al. 2013 10 Ogutu et al. 2014

11 Bolger et al. 2008 12 Fynn & Bonyongo 2011 13 Beckmann et al. 2012 14 Middleton et al. 2013

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Table 3.2 General linear models predicting birth weight of argali lambs at Ikh Nart

Nature Reserve, Mongolia, showing number of parameters (k), log likelihood of each model (LL), change in AICc compared to the best-fitting model (∆AICc), Akaike model weight (w), and the parameter estimate with standard error for core zone implementation

(). The full model includes lamb age in days at capture (Age), lamb sex (Sex),

Julian day of lamb birthdate (JD), precipitation from the prior April (AprP), total precipitation from the prior year (YrP), integrated NDVI from the prior year (IntN),

NDVI reading on the prior May 9 (MayN), average low temperature during winter (WT), and before/after livestock reduction in the core zone (Core).

Rank Model k LL ∆AICc w (SE)

1 Sex+AprP+IntN+MayN+Core 7 -175.2 0 .36 0.70 (0.19)

2 Sex+AprP+YrP+IntN+MayN+Core 8 -174.4 0.53 .27 0.98 (0.29)

3 Sex+IntN+MayN+Core 6 -176.9 1.11 .20 0.72 (0.19)

4 Sex+JD+AprP+YrP+IntN+MayN+Core 9 -174.1 2.33 .11 0.91 (0.31)

5 AprP+IntN+MayN+Core 6 -178.7 4.60 .04 0.68 (0.19)

6 Age+Sex+JD+AprP+YrP+IntN+MayN+WT+Core 11 -173.8 6.41 .01 0.89 (0.32)

7 Sex+AprP+YrP+IntN+MayN 7 -180.2 9.84 0 -

8 Sex+AprP+IntN+MayN 6 -182.1 11.55 0 -

9 Sex+IntN+MayN 5 -184.2 13.43 0 -

10 Sex+AprP+YrP+Core 6 -184.8 16.85 0 0.06 (0.22)

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Figure 3.1 Sampling design for argali lamb birth weights across a livestock before-after treatment in Ikh Nart Nature Reserve, Mongolia. Human and livestock density was reduced by 40% inside the core zone in 2006.

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Figure 3.2 Argali lamb capture locations at Ikh Nart Nature Reserve, Mongolia, 2003-

2013.

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Figure 3.3 Argali lamb birth weights (bars = standard error) and NDVI at Ikh Nart

Nature Reserve, Mongolia, 2003-2013. The red vertical line indicates when livestock were reduced in the core zone.

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CHAPTER 4

FACTORS INFLUNCING SURVIVAL OF JUVENILE AND ADULT

ARGALI IN MONGOLIA’S GOBI STEPPE

L. STEFAN EKERNAS, University of Montana, Wildlife Biology Program, College of

Forestry and Conservation, Missoula, MT 59812, USA

GANCHIMEG J. WINGARD, Denver Zoological Foundation, Conservation and

Research Department, Denver, CO 80205 USA

SUKH AMGALANBAATAR, Argali Wildlife Research Center, Ulaanbaatar, Mongolia

RICHARD P. READING, University of Denver, Department of Biology & Graduate

School of Social Work, Denver, CO 80208 USA

JOEL BERGER, Wildlife Conservation Society, Bronx, NY 10460 USA & Colorado

State University, Fisheries, Wildlife, and Conservation Biology, Fort Collins, CO

80523 USA

ABSTRACT

Telemetry studies spanning multiple years typically experience loss or failure of very high frequency (VHF) transmitters, which are crucial to locating study animals.

Transmitter failure causes individuals to revert to a state of substantially lower detection probability, and researchers often deal with this complexity by censoring or truncating capture histories at time of transmitter failure. In studies where individuals can still be identified through other permanent marks such as ear tags, researchers may detect animals long after transmission failure. Censoring these data removes multiple animal-

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years of sampling effort. Here, we demonstrate how to avoid these data losses by explicitly modeling transmitter failure probability in a multistate mark-recapture model that transitions individuals with failed transmitters into states with lower live detection probability and nonexistent dead recovery. Our dataset focuses on argali Ovis ammon from Mongolia’s Gobi steppe in a staggered entry 136 month long telemetry study involving 184 individuals of all age classes, and we build a Bayesian multistate model that uses a hierarchical approach to model both the survival process and the observation process. We calculate survival of four age classes: newborns (0 months old), lambs (1-11 months), yearlings (12-23 months), and adults (≥ 24 months). In addition, we estimate effects of individual variables, environmental variation, and a livestock reduction on survival of all age classes. Livestock reduction and vegetation (normalized difference vegetation index, NDVI) positively associated with survival of newborns and lambs, but did not predict adult survival. We found large effects of livestock reduction on both newborn and lamb survival. In an average NDVI year, livestock reduction increased newborn survival in the first month by an absolute 17% and increased lamb survival in the subsequent eleven months by an absolute 64%. Lamb survival is largely driven by resource availability, since NDVI and livestock reduction explained 99% of the annual variation in lamb cohort survival. Adult females appear to reduce investment in offspring during low resource years, which may buffer their survival against environmental variation and livestock grazing.

INTRODUCTION

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Complex data often require complex models. Studies on rare, wide-ranging

species in developing countries rarely follow ideal study designs with comprehensive

sampling. Ignoring complexities in both biological and sampling processes leads to

oversimplified analyses, causing researchers to censor data points that obviously violate

fundamental assumptions of a particular analysis (DeCesare et al. 2016). An alternate

approach is to model the underlying complexity in both biological and sampling

processes, verifying the model by fitting it to stochastically simulated data generated

from known parameters.

Telemetry – whereby individual animals are fitted with a very high frequency

(VHF), Global Positioning System (GPS), or satellite transmitter and subsequently

tracked – is the most effective way to estimate survival in mobile, long-lived species

(Millspaugh & Marzluff 2001). Under ideal sampling schemes, marked animals can be

found with perfect detection probability = 1.0, allowing researchers to estimate survival

using known-fate models (Kaplan & Meier 1958; Pollock et al. 1989). When researchers

cannot detect marked animals with near certainty, analyses need to estimate both survival

and detection probabilities. A variety of factors can cause imperfect detection of animals

with VHF transmitters. For example animals may move outside the study area, or

researchers may not be able to comprehensively search large home ranges in a single day.

Relatively simple mark-recapture models (Jolly-Seber models, joint live-dead analysis) can incorporate these scenarios, including temporal variation in detection and survival

(Amstrup et al. 2010).

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A more pernicious problem is when VHF transmitters fail or are lost, causing animals to transition to a state with lower detection probability while remaining identifiable. Devineau et al. (2014) used a multistate model to address this problem in

Canada lynx (Lynx canadensis) that lost GPS satellite transmitters and subsequently transitioned into imperfect detection with VHF transmitters. Because detection probability was perfect with satellite transmitters, transmitter failure occurred at a known time point at which Devineau et al. (2014) manually transitioned animals into a new state.

However, when baseline detection is imperfect, transmitter failure can go undetected permanently or for many sampling periods, meaning that we cannot manually transition individuals. Furthermore, individuals whose transmitters fail can often be detected only alive but cannot be recovered dead since carcasses are difficult to find and scavengers destroy individual marks such as ear tags. Transmitter failure is common in multi-year telemetry studies, and researchers often respond by censoring or truncating capture histories (DeCesare et al. 2016). In studies where individuals are long-lived and occasionally detected after transmitter failure, such data censoring can remove multiple animal-years of sampling effort. We can avoid these data losses by explicitly modeling transmitter failure and differing detection probabilities in a mark-recapture multistate analysis.

Here, we use a Bayesian multistate model to identify factors influencing survival of argali (Ovis ammon) at Ikh Nart Nature Reserve (INNR), Mongolia. Previously we investigated whether livestock reduction inside a core zone at INNR affected argali lamb birth mass (Chapter 3); now we capitalize on the same before-after livestock reduction treatment to also investigate effects on argali survival, while accounting for

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environmental variation. The multistate model includes four age classes – newborns (0

months), lambs (1-11 months), yearlings (12-23 months), and adults (≥ 24 months) – and incorporates aging and two processes that transition animals into states with different detection probabilities. These two transition processes are VHF transmitter failure and temporary movements on and off the study area. Survival probability varies between years, and we calculate associations between survival and precipitation, vegetation

(normalized difference vegetation index, NDVI), and livestock reduction.

METHODS

Study site, core zone, and livestock reduction

INNR (660 km2 centered on 45.6oN, 108.7oE) lies in the central Mongolia’s Gobi

desert steppe. The climate is harsh, with temperatures ranging from -40o C in winter to

+43o C in summer and approximately 100 mm of precipitation in an average year (Airag weather station, 2014). Wingard et al. (2011a) estimate that 600 argali inhabit northern

Ikh Nart, and we guess that another 100-200 argali live in southern Ikh Nart.

Just over 100 semi-nomadic pastoralist families use INNR for all or part of the year. Livestock at INNR outnumber argali approximately 50:1, and livestock consume ten times more forage than argali (Ekernas et al. In Press; Wingard et al. 2011b). In 2006,

managers at INNR reduced livestock density in a 71 km2 core zone of key argali habitat

when three pastoral families voluntarily moved away with their livestock, effectively

reducing human and livestock density by 40% inside the core zone (Ekernas et al. In

Press).

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Argali captures

We captured argali of all age and sex classes from 2002-2013, fitted them with

VHF and/or GPS collars, and tracked them. We conducted captures twice per year: in

spring (late March through early May) when we hand-captured newborns in their first

week of life, and September when we used drive-nets to capture animals of all age classes

(Kenny et al. 2008). Upon capture, we weighed each animal, recorded age and sex,

measured various morphological features, marked them with unique ear tags, and fitted

all animals with a VHF transmitter and a subset with also a GPS or satellite transmitter.

We weighed animals by placing newborns in a cloth bag and older animals on a canvas tarp attached to a hanging scale, and measured weight to the nearest 0.1 kg. To reduce

stress and disturbance, we covered animals’ eyes, minimized handling times (mean

handling time = 11.7 minutes), and for newborns we immediately departed the capture

area after release. Denver Zoological Foundation, Mongolian Conservation Coalition,

Mongolian Academy of Sciences, and Argali Wildlife Research Center conducted

captures using methods approved by Mongolian Academy of Sciences.

Measuring environmental covariates: NDVI, precipitation, and winter temperature

In the Gobi Desert, forage availability for ungulates is closely linked to precipitation and NDVI (Berger et al. 2013). We obtained NDVI readings for the years

2002-2013 (NASA Land Processes Distributed Active Archive Center, MOD13Q1 data).

We averaged NDVI readings inside two areas using QuantumGIS (Quantum GIS

Development Team 2016): all of INNR (666 km2), and the smaller core zone (71 km2) inside INNR. For each of these two areas we focused on two specific NDVI readings.

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First, we used the NDVI reading from May 9 of each year, which is the earliest date that

NDVI detects green-up at INNR. Winters at INNR are long and harsh, and spring

represents the most difficult time of year for ungulates (Begzsuren et al. 2004; Tachiiri et al. 2008). NDVI on May 9 therefore measures forage availability during a critical time of year. Second, we measured integrated NDVI over the whole year, which represents cumulative plant growth over the entire growing season, by calculating area under the curve with NDVI value of 0.125 set as a floor; NDVI values over 0.1 can indicate green forage availability in the Mongolian Gobi (Leisher et al. 2012), but ground-truthing vegetation at our study site indicates that 0.125 is a more accurate minimum NDVI value for green-up. NDVI readings from the core zone and all of INNR were strongly correlated (May 9 NDVI r2 = 0.94; yearly integrated NDVI r2 = 0.83), and in our analyses we use NDVI values from only the core zone since all argali we fitted with GPS collars used the core zone whereas other sections of INNR were only used by some individuals.

The closest weather station is located 45 km east of INNR in the town of Airag, which has similar elevation and vegetation to INNR. We used daily readings of precipitation as well as minimum and maximum temperature at the Airag weather station from 2002-2013. Because severe winter temperatures are associated with lower birth mass in Mongolian gazelle (Olson et al. 2005), we measured winter severity by calculating the mean daily minimum temperature from December 1 – March 15. We measured April precipitation by summing daily precipitation from April 1 to April 30, and measured yearly precipitation by summing daily precipitation from January 1 –

December 31.

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Measuring argali survival: field and analytical methods

Telemetry

We fitted argali with one of two types of VHF transmitters: one for newborns and one for all other age classes. Newborn lambs received small VHF transmitters attached to expandable collars designed to stretch and eventually break off as the lamb’s neck girth increased with age (“lamb collars”; Diefenbach et al. 2003). Lamb collars typically fell off between ages 10-18 months. Collars fitted on older animals functioned for considerably longer, and battery depletion, transmitter failure, and collar breakage meant that VHF / GPS transmission lasted for variable periods of time lasting up to 9 years. We fitted lambs captured in September – 5 months old and approximately 40% the weight of an adult female – with either adult or lamb collars depending on collar availability and number of animals captured. We used livestock ear tags to permanently mark all animals captured, meaning we could still identify animals whose VHF transmitter had failed.

We tracked collared animals via telemetry for 1-3 weeks each month, with researchers recording the individual identity of the animal, cause of death for deceased animals, GPS location, and age-sex group composition. Our dataset spans 136 months from September 2003 through December 2013. Tracking occurred primarily on foot, and occasionally by vehicle. We limited most of our survey effort to a ~20km radius from the research camp (“the study area”). In total we captured and tracked 184 animals at INNR in a staggered entry design: 126 newborns, 11 lambs captured in September when approximately 5 months old, 7 yearlings, and 44 adult females. Our dataset spans 6332

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animal-months, and we recovered 89 confirmed mortalities: 75 lambs, 8 yearlings, and 6 adults.

Multistate parametrization

We used a multistate model to incorporate the complexity inherent to our sampling. We explicitly modeled collar failure probability (L) to allow individuals to

transition from a collared to uncollared state. From that point we parametrized the multistate model as a joint live-dead model (Kéry & Schaub 2012), with the following states for each age class: i) collared on the study site, ii) collared off the study site

(unobservable), iii) uncollared on the study site, iv) uncollared off the study site, v) newly

dead (defined as having died in the prior month, with recovery probability r), and vi) old

dead (unobservable and defined as having died before the prior month; Figure 4.1). We kept parameters specifying biological processes (survival S and movements F and F’) identical for collared and uncollared animals, but differed parameters specifying the observation process (detection and recovery probabilities pc, pu, rl and ra). Because we

had no dead recoveries of uncollared animals, these animals transitioned directly to the

unobservable state ‘old dead’ upon death. In total, our multistate model incorporates 16 states (Figure 4.2). Individuals could transition between states each month, and move into

new age classes each April to match the annual birth pulse. In the model, years

correspond to April 1 – March 31. Our model estimates 18 general parameters, 2 of

which encompassed yearly variation, for a total of 39 parameters (Table 4.1).

Differential detection probabilities across individuals, age classes, and geographic areas

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Several factors influence detection probability of marked individuals. First,

individual animals move in and out of the study area, which we confirmed from movements of GPS-collared individuals (Figure 4.3). While in the study area, an individual has a probability p of being detected each month, but when out of the study area it could not be detected (p = 0). We calculated movement probabilities for remaining in the study area (fidelity, F) or returning to the study area when outside it (F’).

Second, individuals lost collars or collar function over the course of the study, meaning that animals could transition from a state of high detection probability

(“collared”) to a state of low detection probability (“uncollared”). Uncollared animals

were more difficult to both locate in the landscape and individually identify since argali

are skittish and ear tags are difficult to discern at long distances. Detection probability for

collared animals (pc) was therefore much higher than detection probability for uncollared

animals (pu).

Furthermore, collared and uncollared animals had different dead recovery

probabilities (r). Of the 89 mortalities we recovered, all came from animals with functioning VHF collars; no ear-tagged but uncollared dead argali was recovered during the study. We therefore set recovery probability for uncollared animals equal to zero. In a mark-recapture framework, collared animal capture histories therefore follow a joint live- dead model where both live re-sightings and dead recoveries occur, whereas uncollared animals follow a Jolly-Seber model with only live re-sightings (Amstrup et al. 2010). To account for the possibility that recovery probabilities differed between age classes, we estimated separate recovery probabilities for lambs (rl) and adults (ra).

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Temporal variation

In the model survival varies between years for newborns, lambs, and adults. We lacked sufficient data on yearlings to estimate temporal variation in survival; for yearlings we therefore kept survival constant across years. For most large mammals, juvenile survival has more variance and is more sensitive to environmental variation than adult survival (Gaillard et al. 1998, 2000). We treated yearly variation differently in adults compared to juveniles. For adults, we treated year as a random effect. Observed temporal variation in survival is a consequence of both environmental process variance and sampling variance, but we are only interested in process variance. To separate sampling from process variance, we treated year as a random effect for adults, which provides an overall mean survival rate while dampening fluctuations between years

(Grosbois et al. 2008; Morris et al. 2011). For newborns and lambs, we allowed survival to vary between years as a function of both NDVI and the 2006 livestock reduction (see below for model selection techniques), but we treat year as a fixed effect because – unlike for adults – we are interested in explicitly comparing lamb survival from one year to the next.

We held all other parameters constant over time. Movement probabilities F and

F’ are difficult to estimate since the model must infer them from an unobservable state; we therefore kept F and F’ constant over time. Monitoring effort was consistent between years, as evidenced by researchers detecting similar numbers of argali groups between years (mean number groups recorded per year = 1355; standard deviation = 334; range:

992-1981; no trend over time). We assumed constant detection probabilities – both live re-sightings p and dead recoveries r – between years.

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Model implementation: Markov Chain Monte Carlo sampling

We analyzed the multistate model in a Bayesian framework, which provides two primary advantages over a frequentist approach. First, we could explicitly incorporate

prior knowledge about both argali ecology and telemetry sampling into our analysis.

Second and more importantly, a Bayesian approach allowed us to improve parameter

estimates by incorporating independent data (skulls and population vectors) in an

integrated population model to improve parameter estimates, although we do not present

those results here (see Chapter 5). We adapted code from Kéry & Schaub (2012) to build

a multistate model in program JAGS (Plummer 2003) that conducted Markov Chain

Monte Carlo (“MCMC”) called from program R.

We used prior probability distributions that restricted the model to biological

reality while giving the model more flexibility than we expect is needed. For example we

restricted mean monthly adult survival Sa to a minimum of 0.94 (= 0.48 yearly survival),

which is considerably lower than what we expect since we commonly observe adults older than 10 years. We set no restrictions on parameters for which we expected high variation and/or had little prior information (e.g. newborn survival Sn and fidelity F, each

given a uniform prior of 0 to 1).

The sampler ran three parallel MCMC chains, each with a burn-in period of

50,000 iterations followed by posterior distribution sampling from a further 100,000 iterations. MCMC sampling took 5 days to complete. We used median values of the posterior distribution as the closest estimate of truth since many of our posterior distributions were non-normal; parameters bounded by [0,1] often have non-normal

93

posterior distributions when parameter estimates fall close to the boundaries (e.g. monthly survival probability for adult argali).

Explanatory variables and model selection: identifying effects of livestock reduction

Numerous factors potentially influence argali survival, including sex, birth mass, forage availability, and winter severity. To identify the effect of the livestock reduction

on argali lamb survival, we included six explanatory variables (Table 4.2) and conducted

model selection to test whether livestock reduction predicted yearly variation in lamb

survival. To reduce total computation time we used a combination of Bayesian and

frequentist methods, following Kéry & Royle (2015), to identify associations between argali survival and explanatory variables including livestock reduction.

We conducted a three-step approach for model selection and estimating parameters. First we ran the Bayesian multistate model with no covariates, but allowing

survival of all age classes (except yearlings) to vary between years. Second, we used

yearly survival estimates from step 1 as the response variable, fit regression models to

these survival estimates, and conducted model selection for different explanatory

variables using a frequentist AICc approach; we ran separate models for newborn, lamb,

2 and adult survival. We also evaluated the top AICc model based on overall r and p-

values for each explanatory variable as an absolute measure of model fit to ensure that

2 the top AICc model had predictive power, rejecting models with r < 0.1 and models that incorporated explanatory variables with p > 0.1. Third, we entered variables from the top

AICc model into the multistate model, which conducted MCMC sampling to estimate

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parameter values for both argali survival and the effects of explanatory variables on survival.

Simulation results

We simulated three capture histories with the same sample size as our dataset to confirm that the multistate model could accurately identify parameters. From simulated data with known parameter values, the multistate model accurately portrayed overall patterns and the effects of livestock reduction and NDVI on lamb survival in both the first and subsequent 11 months (Figure 4.4). We expect to misidentify 2 or 3 parameters due to random chance with 95% credible intervals estimating 48 parameters. Models from simulated datasets missed between 3 and 7 parameters. Nearly all misses measured survival of a particular age class in a particular year, though one simulated dataset also missed parameters LL and rA. Misses were not consistent between datasets, suggesting

that missed parameters stemmed from low sample size rather than model bias. We knew

prior to analysis that sample size was limited for yearling survival, and simulation results

confirmed our expectations: precision was very low in all simulated datasets, and one

dataset did not contain the true value within the 95%CrI. Simulated data indicated that we

lacked sufficient precision to identify a significant difference in survival between male and female lambs. The model consistently estimated the true simulated effect of sex on lamb survival within its 95% credible interval, but in only one of the three simulated datasets did the model determine that the difference was significantly different from 0.

RESULTS

95

MCMC results

The three MCMC chains converged, with Gelman and Rubin’s (1992) diagnostic

< 1.06 for all parameters ( values below 1.1 indicate that chains converged; Table

4.3). Posterior distributions were all unimodal and distinctly different from prior

distributions for all parameters except one, indicating that priors did not affect posteriors

in all but one case. The exception was survival of yearlings Sy, for which the lower-bound

of the prior influenced the lower-bound of the posterior distribution; simulated data indicated that our sample size (n = 7 captured individuals) was too low to accurately estimate this parameter.

Survival of newborns, lambs, yearlings and adults

Survival increased, and variance in survival decreased, with age class (Figure

4.5). Yearlings potentially did not fit this pattern as the estimate for yearling survival was

lower than lamb survival, but we have little confidence in the yearling survival estimate

because of limited sample size. Adult survival had substantially lower year-to-year

variance than did newborn or lamb survival.

Covariation between parameter estimates

We ran single regression analyses with parameter estimates from each MCMC

run and found no associations between survival estimates for any age class and

parameters related to detection probability. However, several parameters related to

detection probability were associated with each other, indicating that the model had

difficulty isolating certain parameters inside shared parameter space. Fidelity to the study

96

2 area F was associated with detection probability for collared animals pc (r = 0.50, slope

2 = -0.89), whereas F’ was associated with detection probability for both collared pc (r =

2 0.47, slope = 0.31) and uncollared animals pu (r = 0.44, slope = -0.50).

Factors predicting survival

The factors that best predicted newborn survival during the first month were

livestock reduction and birth mass, although we note that these factors explained only a

small amount of the individual variation in survival (r2 = 0.09; Table 4.4a). We entered

these explanatory variables into the multistate model, which indicated that newborn

survival was higher after livestock reduction in 2006 (βcore = 3.33, 95% Credible Interval:

0.13 – 7.80) but found no significant effect of birth mass (βmass = 0.005, 95% Credible

Interval: -1.00 – 1.01; Table 4.3). Translating this β value to real survival, livestock

reduction increased newborn survival by a raw 17.5% (95% Credible Interval: 1.8% –

18.3%), from 46% survival pre-reduction to 63% survival post-reduction in an average

NDVI year.

NDVI and livestock reduction predicted lamb survival during months 1 through

11 (Table 4.4b; Figure 4.6). The multistate model found positive associations between lamb survival and both NDVI (βNDVI = 34.4, 95% Credible Interval: 11.4 – 64.9) and livestock reduction (βcore = 2.39, 95% Credible Interval: 1.27 – 4.01). Translated into real

survival, livestock reduction increased lamb survival from age 1 month to 12 months by a

raw 64%, from 19% survival pre-reduction to 83% survival post-reduction in an average

NDVI year. AICc model selection indicated that lamb sex also predicted survival, with

males having approximately 3% lower monthly survival than females, but the multistate

97

model found no significant difference between males and females (βmale = -3.34, 95%

Credible Interval: -9.48 – 2.19); simulated data indicate that our sample size was too small for the multistate model to detect a 3% difference in monthly survival between males and females. No factors predicted adult survival.

DISCUSSION

We found large effects of livestock reduction on both newborn and lamb survival.

In an average NDVI year, newborn survival in the first month increased by an absolute

17% and lamb survival in the subsequent eleven months increased by an absolute 64%.

These results provide strong evidence that livestock detrimentally affect argali.

Furthermore, since we reduced livestock density inside only a small core zone, our study design simultaneously provides a robust test of a widely adopted but rarely evaluated management strategy: core zones. Core zones, where anthropogenic disturbance is minimized in a small part of a larger protected area, are used in many protected areas across Central Asia including in Mongolia, China, and the Indian trans-Himalaya (Mishra et al. 2004; Kaczensky et al. 2008; Suryawanshi et al. 2010; Townsend et al. 2014; Li et al. 2014). Their efficacy in affecting wildlife vital rates has not been evaluated previously, to our knowledge.

Livestock likely impose forage competition on argali at INNR. Diet overlap between livestock and argali is high (Wingard et al. 2011b), livestock remove roughly ten

times more forage than argali (Chapter 2), livestock range in all areas of INNR where

argali are found, and at least some argali age classes are bottom-up limited and thus

susceptible to reductions in resource availability. Indeed, livestock reduction and NDVI

98

explain 99% of the annual cohort variation in lamb survival after the first month (Figure

4.6b). Newborns are more vulnerable to predation, which may be the reason why NDVI

and livestock reduction predict less (45%) of the annual variation in newborn survival

(Figure 4.5a). However, we caution that our parameter estimates for newborn survival likely encompass more sampling error than for lamb survival. Newborn survival spans

only a single sampling period each year, whereas lamb survival spans 11 sampling

periods (months) each year.

We could explain much more of the cohort variation in survival (r2 = 0.45 and

0.99 for newborns and lambs respectively) than the total variation (r2 = 0.14 and 0.63

respectively; Table 4.4). Total variation encompasses individual plus cohort variation,

and although we included lamb sex and birth mass as individual-level explanatory

variables, these did not have strong effects on survival. We did not know the identity of

mothers for the vast majority of VHF-collared lambs, and we had no information on

maternal factors, such as body condition and reproductive history, that influence lamb

survival in other wild and domestic sheep (Jones et al. 2005; Martin & Festa-Bianchet

2010). Maternal factors therefore added unexplained variation (‘noise’) to our data,

reducing our ability to identify effects of environmental factors on newborn and lamb

survival. Individual effects outweigh cohort effects on lamb survival in feral Soay sheep

(Ovis aries, Jones et al. 2005). That we found associations between survival and both

NDVI and livestock reduction despite lacking knowledge on many individual factors

speaks to the strength of environmental effects in our study system.

The multistate model had trouble identifying some parameters related to detection

probability. Low detection probability for uncollared animals pu leads to long periods of

99

non-detections in capture histories; the model had trouble isolating parameters when

multiple combinations of parameters relating to the observation process could explain

these results (for example low F and F’ values also predict long strings of undetection, as

does low probability for dead recovery r). Lack of clarity would be troublesome if it

affected the model’s ability to estimate survival. However, single regressions of results

from each MCMC run showed no association between parameters estimating survival

and parameters estimating the observation process. More problematic is that we were

unable to estimate yearling survival. Simulated data confirmed that our sample size was

not just too low to allow temporal variation, but too low to accurately estimate survival even in the absence of temporal variation. Of the n = 62 argali we captured in September, only 7 were yearlings. Newborn captures yielded little data on yearling survival, both because many animals died prior to reaching 12 months and because lamb VHF collars were designed to expand and eventually fall off as lambs’ neck circumference increased with age. Lack of data on yearling survival represents the biggest weakness in our dataset.

Effects from livestock reduction on lamb survival mirror the effects on lamb birth mass, which increased by 18% post-reduction after accounting for annual variation in precipitation and NDVI (Chapter 3). Interestingly, we found only weak associations between birth mass and survival. Reduced birth mass (which measures maternal investment in lambs during gestation) may be one pathway by which livestock reduction influenced lamb survival, but other mechanisms also appear to be at work. Just like birth mass, these other mechanisms presumably also function through maternal effects, since both livestock reduction and NDVI affected lamb survival in the next – not the current –

100

year. Bighorn sheep ewes (Ovis canadensis) restrict post-partum investment in lambs during years with low resources (Festa-Bianchet & Jorgenson 1998; Martin & Festa-

Bianchet 2010). Adult female argali similarly appear to reduce both gestational and post- partum investment in offspring to compensate for fluctuating resource availability, potentially explaining why neither livestock reduction nor NDVI predicted adult survival.

As with many other ungulates, argali adult survival was higher, less variable, and less susceptible to environmental factors than juvenile survival (Gaillard et al. 1998, 2000).

Natural selection generally promotes low variation in the vital rates with the highest sensitivity (Pfister 1998; Gaillard & Yoccoz 2003), which is adult survival in most long- lived iteroparous species including argali (Heppel et al. 2000; Oli & Dobson 2003).

ACKNOWLEDGEMENTS

We thank the numerous field staff, local community members, and Earthwatch volunteers who assisted with capturing argali. T. Selenge provided invaluable logistical support. This work was supported by Denver Zoological Foundation, University of

Montana, Wildlife Conservation Society, Colorado State University, Argali Wildlife

Research Center, Earthwatch Institute, and the National Science Foundation (grant DGE-

0504628).

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Table 4.1 Parameters we estimated in the multistate survival model. All parameters estimate the probability of occurrance each month. Shaded parameters represent sampling processes, while unshaded parameters represent biological processes.

Parameter Description Temporal Comments

variation

Sn Survival: newborns (0 mos) Year n=11 years

Sl Survival: lambs (1-11 mos.) Year n=12 years

Sy Survival: yearlings (12-23 mos.) None Low sample size: held constant

Sa Survival: adults (≥ 24 mos.) Year: random effect Overall mean Sa

2 σa Year-to-year variance: Sa -

F Animal stays on study area None Difficult to estimate: held constant

F’ Animal returns to study area None Difficult to estimate: held constant

L Losing adult VHF collar None

LL Losing lamb VHF collar None LL > L; lamb collars drop off

pc Detection: collared animals None

pu Detection: uncollared animals None

rl Dead recovery: lambs None

ra Dead recovery: adults None

βmN-n MayNDVIt-1: effect on Sn - MayNDVI from prior year

βcore-n CoreZone: effect on Sn - Core zone effect on newborn survival

βmN-l MayNDVIt-1: effect on Sl - MayNDVI from prior year

βcore-l CoreZone: effect on Sl - Core zone effect on lamb survival

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Table 4.2 Candidate explanatory variables predicting yearly argali survival, specifying which age classes were affected, with what lag time(s), and what interaction effects we included.

Explanatory Age classes Lag time Interactions

variable affected

MayNDVI Newborns t - 1 *CoreZ

Lambs t - 1, t *CoreZ

Adults t -

IntNDVI Newborns t - 1 -

Lambs t - 1 -

Adults t - 1 -

WintTemp Newborns t -

Lambs t -

Adults t -

CoreZ Newborns t *BirthMass + *MayNDVI

Lambs t *BirthMass + *MayNDVI

BirthMass Newborns NA *CoreZ

Lambs NA *CoreZ

Sex All NA -

108

Table 4.3 MCMC results from the multistate model (n = 100,000 MCMC samples). All parameters represent monthly probabilities; annual juvenile survival probability is

11 calculated by Sn * Sl . Shaded parameters represent sampling processes, while unshaded parameters represent biological processes. Standard error is the standard deviation of

MCMC posteriors. β’s represent logistic equation values, which we translate into real effects on survival in the text.

Parameter Median Standard 2.5% 97.5% Proportion

Error same sign

Sn 2003 0.79976 0.08335 0.58954 0.91645 1.0 1.00158

Sn 2004 0.63282 0.06447 0.48643 0.74431 1.0 1.00056

Sn 2005 0.33137 0.05226 0.24528 0.45264 1.0 1.00114

Sn 2006 0.46932 0.05989 0.35098 0.59318 1.0 1.00008

Sn 2007 0.66863 0.06701 0.53153 0.80361 1.0 1.00006

Sn 2008 0.53515 0.07739 0.39755 0.71121 1.0 1.00060

Sn 2009 0.86635 0.09063 0.67534 0.99857 1.0 1.00193

Sn 2010 0.57963 0.07108 0.44891 0.73566 1.0 1.00021

Sn 2011 0.62886 0.05744 0.51772 0.74863 1.0 1.00016

Sn 2012 0.73744 0.05681 0.61047 0.83865 1.0 1.00014

Sn 2013 0.73795 0.06104 0.60264 0.84266 1.0 1.00127

Sl 2002 0.84836 0.05913 0.69883 0.93178 1.0 1.00056

Sl 2003 0.96773 0.01763 0.92187 0.99004 1.0 1.00130

Sl 2004 0.93449 0.03123 0.84824 0.97068 1.0 1.00051

Sl 2005 0.82034 0.06774 0.64658 0.91006 1.0 1.00070

Sl 2006 0.77443 0.08151 0.57662 0.89039 1.0 1.00122

109

Parameter Median Standard 2.5% 97.5% Proportion

Error same sign

Sl 2007 0.96415 0.02154 0.90118 0.98747 1.0 1.00159

Sl 2008 0.97029 0.01493 0.93104 0.98902 1.0 1.00258

Sl 2009 0.96376 0.02443 0.89188 0.98589 1.0 1.00246

Sl 2010 0.98216 0.01433 0.93874 0.99378 1.0 1.00479

Sl 2011 0.98008 0.01208 0.94767 0.99310 1.0 1.00577

Sl 2012 0.97927 0.01144 0.94996 0.99396 1.0 1.00457

Sl 2013 0.98375 0.00963 0.95912 0.99502 1.0 1.00910

Sy 0.91499 0.01141 0.90078 0.94221 1.0 1.00466 meanSa 0.98671 0.00489 0.97539 0.99442 1.0 1.00393

2 σa 0.49671 1.69610 0.00225 4.87650 1.0 1.00658

F 0.88415 0.01340 0.85645 0.90902 1.0 1.01020

F’ 0.14184 0.03204 0.09150 0.21582 1.0 1.05466

L 0.01889 0.00370 0.01256 0.02702 1.0 1.00645

LL 0.04985 0.02886 0.00252 0.09749 1.0 0.99999 pc 0.90716 0.01809 0.87044 0.94127 1.0 1.02510 pu 0.20796 0.04307 0.14014 0.30595 1.0 1.02089 ra 0.31280 0.07551 0.18191 0.47649 1.0 1.00127 rl 0.96717 0.03148 0.88211 0.99833 1.0 1.00473

βbirthMass-Sn 0.00450 0.50290 -0.99609 1.00749 0.50356 1.00059

βcore-Sn 3.32881 1.99554 0.12770 7.79882 0.97954 1.00088

βsexMale-Sl -3.33929 2.89997 -9.47844 2.18725 0.89128 1.01030

βNDVI-Sl 34.41105 13.24932 11.41022 64.85003 0.99704 1.00439

βcore-Sl 2.38622 0.69351 1.26928 4.01378 0.99998 1.00365

110

Table 4.4 AICc comparison of general linear models predicting survival of argali (a)

newborns (aged 0 months), and (b) lambs (aged 1-11 months), at Ikh Nart Nature

Reserve, Mongolia, from 2003-2013. Columns show number of parameters (k), log

likelihood of each model (LL), AICc value, change in AICc compared to the best-fitting model (∆AICc), kaike model weight (w), and the top model’s multiple r2. The full model includes lamb sex (Sex), lamb birth mass (bMass), average NDVI inside the core zone on

May 9 of the prior year (mNDVI), before/after livestock reduction in the core zone

(Core), and interactions between the livestock reduction and birth mass as well as NDVI.

(a) Factors predicting argali newborn survival in the first month after birth. AICc

provided moderate support for a complex 8-parameter model in which several variables

had little predictive power (p > 0.05). We instead selected the second AICc ranked model

(bMass+Core) – in which all parameters were significantly associated with newborn

survival (p < 0.05) – for MCMC sampling in the multistate model.

2 Rank Model k LL AICc ∆AICc w r

1 Sex+mNDVI+bMass+Core+Core*mNDVI 8 -71.64 160.63 0 0.26 0.14

2 bMass+Core 4 -76.39 161.13 0.51 0.2 0.09

3 Sex+bMass+Core 6 -74.5 161.77 1.14 0.15

4 Sex+mNDVI+bMass+Core 7 -73.48 161.99 1.37 0.13

5 Sex+bMass+Core+Core*BirthMass 7 -73.91 162.85 2.22 0.09

6 Sex+mNDVI+bMass+Core+Core*bMass+Core*mNDVI 9 -71.62 162.93 2.31 0.08

7 Sex+mNDVI+bMass+Core+Core*bMass 8 -73.18 163.71 3.09 0.06

8 Sex+bMass 5 -77.83 166.21 5.59 0.02

9 mNDVI+Core 4 -80.55 169.42 8.8 0

10 Sex+mNDVI+Core 6 -78.43 169.57 8.94 0

11 Sex+Core 5 -81.45 173.41 12.79 0

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(b) Factors predicting argali lamb survival from 1-11 months. AICc unambiguously supported the Sex+MayNDVI+Core model, which we incorporated for MCMC sampling in the multistate model.

2 Rank Model k LL AICc ∆AICc wr

1 Sex+mNDVI+Core 5 178.1 -345.4 0.0 1 0.63

2 mNDVI+Core 4 171.1 -333.7 11.7 0

3 Sex+Core 4 165.0 -321.5 24.0 0

4 Sex+bMass+Core+Core*bMass 6 144.2 -275.0 70.5 0

5 Sex+mNDVI+bMass+Core+Core*bMass 7 144.7 -273.5 71.9 0

6 Sex+mNDVI+bMass+Core+Core*bMass+Core*mNDVI 8 144.7 -271.0 74.5 0

7 Sex+mNDVI+bMass+Core 6 139.5 -265.6 79.9 0

8 Sex+mNDVI+bMass+Core+Core*mNDVI 7 140.6 -265.3 80.1 0

9 Sex+bMass+Core 5 137.7 -264.5 81.0 0

10 bMass+Core 4 132.8 -257.0 88.4 0

11 Sex+bMass 4 111.3 -214.0 131.4 0

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Figure 4.1 States and transitions for a single age class in the multistate model.

Transitions occur monthly. Animals enter the study as alive, collared, on the study area

(top left box). The probability of remaining in that state into the next month is calculated as S*(1-L)*F: the animal must survive, not lose its collar, and stay on the study area.

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Figure 4.2 Framework of the mark-recapture multistate model, incorporating both live recaptures and dead recoveries of collared animals (joint live-dead analysis, left column)

but only live recaptures for uncollared animals (Jolly-Seber model, right column). Boxes represent states, and arrows represent transition probabilities. To reduce clutter, many possible transitions between boxes are not shown.

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Figure 4.3 Minimum convex polygon home ranges of GPS-collared adult argali (n = 10) in relation to Ikh Nart Nature Reserve, the core zone, and newborn capture locations

(n=130). The core zone comprised 18-60% of most (n = 9) animals’ home ranges, but comprised only 1% of home range for one migratory individual. The study area roughly

matches the core zone.

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Figure 4.4 Histograms of posteriors from MCMC samples of simulated data. Red bars represent the true simulated value for each parameter. Arrows indicate when the true value fell outside MCMC 95% Credible Intervals.

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Figure 4.5 Monthly survival probability of argali adults, lambs, and newborns at Ikh Nart

Nature Reserve, Mongolia, 2002-2012 (bars = standard error). Sampling for newborns began in 2003. Yearling survival is not included since low sample size prevented us from both accurately estimating survival and incorporating temporal variation.

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Figure 4.6 Argali (a) newborn survival in the first month, and (b) lamb survival from1 month to 12 months (bars = standard error) in relation to Normalized

Difference Vegetation Index at Ikh Nart Nature Reserve, Mongolia, from 2002-

2013. The red vertical line indicates livestock reduction in the core zone. We began sampling lamb survival in 2002 but newborn survival in 2003.

(a)

(b)

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CHAPTER 5

LIVESTOCK, CORE ZONES, AND POPULATION DYNAMICS OF

GOBI ARGALI

L. STEFAN EKERNAS, University of Montana, Wildlife Biology Program, College of

Forestry and Conservation, Missoula, MT 59812, USA

GANCHIMEG J. WINGARD, Denver Zoological Foundation, Conservation and

Research Department, Denver, CO 80205 USA

SUKH AMGALANBAATAR, Argali Wildlife Research Center, Ulaanbaatar, Mongolia

RICHARD P. READING, University of Denver, Department of Biology & Graduate

School of Social Work, Denver, CO 80208 USA

JOEL BERGER, Wildlife Conservation Society, Bronx, NY 10460 USA & Colorado

State University, Fisheries, Wildlife, and Conservation Biology, Fort Collins, CO

80523 USA

ABSTRACT

When evaluating a conservation intervention, a key arbiter for judging success is whether the intervention increases population growth. In Central Asia, rapid increases in livestock density are thought to threaten biodiversity, but to date no study has demonstrated direct links between livestock and population growth of native species. We previously demonstrated that a livestock reduction in Mongolia’s Gobi steppe affected wild argali (Ovis ammon), increasing lamb birth mass and juvenile survival. Here, we investigate whether observed changes in juvenile survival also affect population growth.

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To improve parameter estimates for vital rates, we incorporate three independent analyses into a single Bayesian integrated population model (IPM): mark-recapture survival analysis of telemetry data, a constant binomial (known fate) analysis of adult female survival from a sample of skulls, and a retroactive population model that sequentially predicts 11 years of observed population vectors at our study site from estimated vital rates. The model then places these vital rates into Lefkovitch matrices and stochastically projects populations 20 years into the future to estimate population growth λs. The IPM substantially improved parameter estimates for vital rates compared to telemetry data alone, isolating process variance and decreasing uncertainty. Population growth across the entire study period 2003-2013 was negative with λs = 0.96, but there was a stark difference in λs pre- and post- livestock reduction. Accounting for environmental differences and covariation between vital rates, livestock reduction increased annual population growth by 0.09 (95%CI: 0.03 – 0.15) from λs = 0.91 to λs = 1.00. We also found strong signals of bottom-up limitation – with 10% changes in normalized difference vegetation index (NDVI) predicting 2% changes in λs – suggesting that the argali population is indeed susceptible to forage competition from livestock. These results provide empirical evidence that livestock detrimentally affect argali, and simultaneously demonstrate that reducing livestock density inside even relatively small core zones of important wildlife habitat can improve conservation outcomes for native herbivores.

INTRODUCTION

Acquiring knowledge about population growth is key to understanding whether a conservation intervention is effective (Wisdom et al. 2000). To do so requires

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information on several parameters, such as vital rates or population size, that are subject

to both sampling and process noise (Caswell 2001; Mills 2012). Reducing uncertainty in

these parameters enhances our ability to accurately and precisely estimate population growth, especially when effect sizes may be small. An effective way to reduce sampling

error is to analyze multiple independent datasets that each measure the same suite of

parameters. Integrated population models (IPM) incorporate numerous analyses into a single model, yielding improved estimates of both vital rates and population growth

(Johnson et al. 2010a; Schaub & Abadi 2011).

In Central Asia, livestock pose a major threat to a large majority of the region’s

native large mammals (IUCN 2015). Numerous studies in arid regions have documented that livestock can affect wild ungulates by altering their diet (Suryawanshi et al. 2010),

displace them from pastures (Hibert et al. 2010; Chirichella et al. 2013), or change their habitat use (Stewart et al. 2002), and correlational studies have shown wildlife responses to changes in livestock density over space or time (Madhusudan 2004; Treydte et al.

2005; Wallgren et al. 2009; Ogutu et al. 2016). However, few studies have demonstrated

livestock effects on population growth of native ungulates. We previously demonstrated

that a livestock reduction in the Gobi steppe positively affected wild argali sheep (Ovis ammon), resulting in increased lamb birth mass (Chapter 3) and juvenile survival

(Chapter 4). Here, we incorporate these and additional analyses into a single IPM that calculates stochastic population growth. Translating changes in vital rates into population growth is critical for assessing livestock effects since the true measure of conservation interest is population change and not survival rates per se. Our primary goals are to: (1) translate effects of livestock reduction from vital rates to population growth, (2) evaluate

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a third line of evidence that livestock reduction in the core zone affected argali, (3)

measure argali population trend at our study site, and (4) improve parameter estimates of

argali vital rates.

We use three independent datasets to estimate argali vital rates, joining them in a

single Bayesian state-space model. Using these vital rates, we project populations into the

future with a three stage Lefkovitch matrix to calculate stochastic population growth, λs

(Caswell 2001). To calculate vital rates we use the multistate mark-recapture survival analysis of telemetry data presented in Chapter 4, and add two further datasets. First is a sample of adult female skulls collected at our study site from 2000-2010 that we use to estimate adult survival. Second, during monthly field surveys we recorded age-sex compositional data of each observed argali group (number of lambs, yearlings, adult females, and adult males). Summing data across groups yields an estimate of population vectors each month 2003-2014. We use these population vectors to create a retroactive population model that predicts successional population vectors from estimated vital rates.

METHODS

Study site and livestock reduction

We focused our analyses on the argali and livestock at Ikh Nart Nature Reserve

(INNR), in central Mongolia’s Gobi desert-steppe. INNR supports about 800 argali, but livestock outnumber argali approximately 50:1 (Wingard et al. 2011; Chapter 2). In 2006,

INNR’s manager (S.A.) decreased human and livestock density by 40% inside a core zone of key argali habitat following the voluntary departure of several pastoral families.

We provide a detailed description of the socioecological system in Chapter 2.

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Statistical analyses and the integrated population model

We conduct all analyses in program R (R Core Development Team 2016) and program JAGS, which is a Gibbs sampler for analyzing Bayesian models with Markov

Chain Monte Carlo simulations (MCMC; Plummer 2003). Bayesian hierarchical models are extremely flexible and can easily incorporate multiple analyses to estimate the same parameter (Kéry & Schaub 2012). We rely on three analyses to improve parameter estimates for vital rates – multistate mark-recapture, a binomial analysis of survival from skulls, and a retroactive population model – that we then place into a stochastic female- only population model to estimate population growth λs and how it is affected by livestock reduction (Figure 5.1). Below we provide details for each of these analyses.

Multistate mark-recapture survival analysis

We calculate survival of collared animals using a multistate parameterization of a joint live-dead analysis that incorporates live re-sightings and dead recoveries while accounting for imperfect detection of both. Details of the analysis are provided in Chapter

4, though we make a few minor revisions for the purpose of the IPM. First, we eliminate all individual effects on survival (sex and birth mass). In Chapter 4 we demonstrate that individual effects had little predictive power, meaning that we lose little information by eliminating these effects. Instead we focus only on cohort survival, which allows us to more accurately estimate effects of NDVI and livestock reduction on survival. Second, we allow yearling survival to vary over time. Our telemetry sample size was too small to allow temporal variation in yearling survival (n = 7 yearlings captured over 12 years), but

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in the IPM we incorporate population vector data that do allow us to estimate annual

temporal variation in yearling survival. We define survival of each age class in year t as:

logit , ∗NDVI ∗ livestock ,

logit , ∗NDVI ∗ livestock ,

logit , ,

where ~0, , ~0, and ~0, represent vectors of error terms

for newborns, lambs and adults that measure annual process variation in survival not explained by environmental factors. We constrain yearling survival in year t such that

, , ,

The state zi,k of each individual i at occasion k as a function of that individual’s

state in the previous occasion k-1, the survival S for the age class of that individual at

occasion k-1, probability of staying on the study area F and moving back into the study

area F’, collar loss probability L and LL, the vector of intercepts µ for each age class, the

vector of coefficients β for environmental factors, and annual process variation σ2 in

survival for each age class such that

Pr(, | ,,,,,,,,,,,, ,, ,,

Observations , of each individual i at occasion k depend on the state xi,k of the individual at that occasion, the live detection probability for collared and uncollared

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animals pc and pu, and the dead recovery probability for collared lambs and adults and

Pr(,| ,,,,,

The likelihood for the multistate mark-recapture process and data models is

Pr( | , ,,,,,, ,, ,,,,,,) =

Multistate survival and transitions Multinomial,| ,,,,,,,,, ,, ,

Telemetry observations

∗ Bernoulli,| ,,,,,

where I is the number of individuals in the study, K is the number of sampling occasions,

and ci is the capture occasion for individual i.

Binomial survival analysis of skulls

We collected skulls (n = 62) of adult females at Ikh Nart from 2000-2010, which

we used to estimate survival (Murie 1944). We estimated survival with a constant

binomial, which is functionally the same as conducting a known-fate analysis when

survival is constant over time (Cooch & White 2016). Calculating survival from skulls in

this manner implicitly assumes that population growth is constant across years, that the population is in stable age distribution, and that collected skulls are representative of

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deaths for the population as a whole (Sinclair et al. 2006). Although we believe our

sample of skulls is representative, we do not know whether skull data meet the other two

assumptions. Nonetheless we believe we are justified in incorporating these data in our

IPM because our data on skulls complement telemetry and other more reliable data.

Furthermore, we construct the model such that survival from skulls informs only overall

random effect mean adult survival without directly influencing estimates of adult survival in any particular year. We use the vector with ages of death of adult female skulls to estimate the random effect mean adult survival . The likelihood for the skulls process

and data models is

Pr( | ) =

Binomial survival Binomial 1 | 1

Where gh is the age of death for adult female skull h, and H is the number of adult female skulls in the sample. We translate monthly adult survival into annual survival via

, and the binomial calculates the odds of not surviving, (1 ). The number of

binomial draws is (gh - 1) because females become adults at age 2, meaning that the

number of adult survival trials for an animal that lives to age g is (g – 1).

Retroactive population model: predict observed population vectors using vital rates

Population vectors – indicating the proportion of lambs, yearlings, and adults –

can inform vital rate estimates. We observed population vectors in consecutive time steps

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and simultaneously estimated vital rates during and between both pre- and post- birth pulse surveys from 2003-2014. We include two time steps q per year: one in May after the birth pulse, and the second one in March immediately before the birth pulse. The population vector is defined as the proportion of each age class present at time step q

The Lefkovitch transition matrix of vital rates in the previous time step q-1

00

, 00 0, ,

where

, ∗ ∗,

and is the average number of newborn lambs that each adult female produces in year t during which the time step q occurs, which we define as

logit ∗NDVI ∗ livestock

Stage based population models (Caswell 2001) describe the biological process through which

relates to , summarized by

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We build a retroactive matrix population model that sequentially goes through

observed population vectors to determine what transition matrix A of vital rates could

predict each observed population vector. Stage based population models are typically used to infer population growth, but we do that separately with a stochastic population model (see below); the sole purpose of this retroactive population model is to improve parameter estimates for vital rates.

Model construction

We predict the entirety of our observed population vector data by building a combined pre-birth pulse and post-birth pulse population model, linking population

vectors with vital rates informed by telemetry and skulls (Figure 5.2). The model has two

time steps per year to explicitly incorporate newborn survival during the first 30 days,

which is substantially lower during the first 30 days than during the subsequent 11

months (Reading et al. 2009; Chapter 4). The first time step spans 2 months from March

1 – May 1 and encompasses the birth pulse which in the model occurs on April 1; the

second time step spans 10 months from May 1 – March 1.

The female-only model begins with pre-birth pulse population vector data

collected in March 2003, which incorporates only two age classes: lambs (aged 0.99

years), and adults combined with yearlings aged 1.99 years (yearlings of this age are

difficult to differentiate from adults in the field). The next population vector is from May

2003, after the birth pulse in April, and now incorporates 3 age classes: lambs (aged 0.1

years), yearlings (aged 1.1 years old and representing the surviving pre-birth pulse

lambs), and adults (≥ 2.01 years). In the model we assume all births occur on April 1, but

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in reality births occur over ~ 4 weeks in April, during which newborn mortality

continuously reduces the number of newborns. Consequently we cannot use age ratios to

directly observe per capita number of female lambs given birth to (reproductive rate R)

but instead infer it from age ratios observed in May, while accounting for survival of

newborns (). All survival rates are monthly, and we take their exponent to the

appropriate number of months in each time step. Mean per capita fecundity in year t is calculated as ∗,, representing number of female lambs surviving to 1 month

produced by an average adult female. Note that only adults that survive from March 1 to

April 1 reproduce; hence total number of lambs produced in May is ∗, ∗.

One subtlety not shown in Figure 5.2 is that yearlings do not reproduce; age of first reproduction for female argali is typically animals who have just turned 3 years old

(Fedosenko & Blank 2005). Therefore, 1.99 year-old yearlings do not contribute to lamb

recruitment even though they are lumped together with adults in March pre-birth pulse

surveys. Including these yearlings in our estimate of recruitment deflates our estimate of

adult per capita reproduction, which is problematic because we separate yearlings and

adults in the stochastic population model that we use to estimate population growth. To

account for 1.99 year-old yearlings not contributing to lamb recruitment we therefore

calculate recruitment using adults from the population vector from the prior May; only

adults who survive can reproduce, so we calculate fecundity each year as ∗, ∗

, multiplied by adults in the population vector from the prior May.

Vital rates in the Lefkovitch matrices

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Vital rates for survival are informed by telemetry data as well as skulls, as

detailed above, and the retroactive population model further refines these estimates. An

important book-keeping point is that the mark-recapture model estimates survival probability per month, and we need to adjust these survival probabilities to match the

length of the time step represented in each transition within the retroactive population

model. Animals transitioning from March to May therefore have to survive 2 time steps,

with probability S*S. May to March represents 10 months, and survival is therefore S10.

We were unable to accurately estimate yearling survival from telemetry because of low sample size. In many temperate bovids, yearling survival falls between adult and lamb survival (Clutton-Brock et al. 1992; Jorgenson et al. 1997; Festa-Bianchet & Côté

2012). We expect the same pattern in argali and therefore restrict yearling survival to fall between lamb survival and adult survival such that , , ,. As a prior, we

assign a uniform probability distribution within this restriction, meaning that yearling

survival is equally likely to fall on any value between , and ,.

Resampling group observations to estimate sampling variance in population vectors

Population vector data are derived from age-sex compositions of observed argali

groups; we calculate proportions based on summed totals of all lambs, yearlings, and

adults observed in a given month. A problem with these data is that an unknown number

of argali groups and individuals were double (or more) counted. Double counting does

not bias the sample mean as long as double-counted groups are randomly sampled and representative of the whole population, but it does artificially reduce variance.

Consequently we cannot measure variance with simple standard error or standard

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deviation. Instead we resample group observations – which simulates the observation

procedure that occurs in the field – and calculate mean and standard error from the

resampled data.

For each March and May 2003-2014, we sampled 30 argali groups with

replacement and summed individual lambs, yearlings, and adults to estimate population

vectors; we repeated this procedure 10,000 times, representing our resampling data.

Resampling was done in a separate analysis outside the IPM, results of which we

provided to the IPM as data. Specifically, we used the mean and standard deviation of resampling data as the mean and standard error in population vectors.

We chose to resample 30 groups because that is how many argali groups we guess

were typically present in our study area during any given month, even though field data

frequently contained more than 100 observed groups in a single month due to double

counts. Results from 30 resamples provide a balance between informing the model while

incorporating a reasonable degree of uncertainty, but we acknowledge that the number 30

is somewhat arbitrary. Sampling substantially more groups reduces standard error to an extent that we subjectively judge as unrealistic; conversely, sampling substantially fewer

groups produces large standard errors that effectively fail to inform the model.

We assume that the observed population vector at time step q is proportional to

the true population vector , and that sampling variance is normally distributed and

calculated from the resampling procedure such that

~ ,

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We use the time series of observed population vectors to estimate the transition matrices containing vital rates from each year. The likelihood for the retroactive

population process and data models is

Pr( | , , ) =

Retroactive population model Sampling variance in ∗ 0,

Where Q is the last time step in the time series, which was March 2014.

Stochastic population model to estimate population growth

Model construction

The above three analyses – multistate mark-recapture, skulls, and the retroactive

population model – estimate vital rates, which we now place into a stage based population model to estimate stochastic growth rate. We construct a post-birth pulse

population model with 3 age classes: lambs, yearlings, and adults (Figure 5.3). Vital rates

for newborns are incorporated into recruitment, shown in A[1,3], but newborns are not

included as a separate age class. Transitions occur over an entire year, from April 1 –

April 1, and survival is therefore measured in year-long rather than monthly increments

such that . Lambs, however, are recruited into the population one month

later on May 1. Recruitment therefore incorporates adult female per capita reproduction

R times one-month newborn survival , and year-long lamb survival occurs over

11 months rather than the full year, meaning . Also note that recruitment

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incorporates adult survival, since births occur at the end of the time step and only adults

who survive the year can reproduce.

We construct 11 A matrices, one for each year 2003-2013, using posteriors from

each vital rate. Although we collected telemetry data on lambs, yearlings, and adults

during 2002 we lack data on both newborns and the initial population vector during this

first year; we therefore begin the population model in 2003. Population vectors are

estimated from observed population vectors with mean and uncertainty calculated from resampling methods described above.

From these matrices we calculate non-asymptotic population growth over twenty years, which represents a conservation-relevant timeframe, while incorporating environmental stochasticity. We first calculate stochastic population growth rate λs for the whole period of the study (Section I) and then in Section (II) estimate the effect of livestock reduction on λs, which we calculate using three different methods (Sections IIA,

IIB, IIC). In Section (I) we calculate non-asymptotic population growth and vital rate

elasticities over the whole study period 2003-2013, effectively running a life stage

simulation analysis within the MCMC sampler (Wisdom et al. 2000; Mills 2012). In

Section (IIA) we calculate effects of the livestock reduction on λs by randomly drawing

Lefkovitch matrices before and after livestock reduction and then comparing λs-before to λs- after, which accounts for vital rate covariation but – critically – does not account for

environmental differences before/after livestock reduction. In Section (IIB) we compare

λs before and after livestock reduction while accounting for differences in environmental

variation, but without accounting for covariation between vital rates. An unfortunate

consequence of using MCMC sampling and Bayesian statistics for population analyses is

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that computing and implementing vital rate covariation is difficult. Consequently, in

Section (IIC) we move outside the MCMC sampler to compare λs-before to λs-after while

accounting for both environmental variation and vital rate covariation, using a life stage

simulation analysis (Wisdom et al. 2000; Johnson et al. 2010b).

Section I. Stochastic population growth λs over entire study, 2003-2013

We begin by estimating non-asymptotic λ over the entire 11-year study while

incorporating both sampling variance and environmental stochasticity. In each simulated

year the population model randomly draws (with replacement) one of the 11 A transition

matrices and multiplies it by the simulated population vector . The model is initiated by

* randomly choosing t as the initial year, and the initial simulated population vector

∗ ∗ where ∗ is the true population vector and the initial total population size

800. The model simulates 20 years, and we calculate stochastic λs as

, where population size at time t is

∗ ∗

We incorporate covariation between vital rates by drawing entire transition

matrices from each observed year (Morris & Doak 2002), obviating the need to compute

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covariation between individual vital rates. We assume that year-to-year environmental

conditions are independent and identically distributed, with no covariation between years.

The likelihood for the stochastic population growth process and data model is

Pr(| ,,,,) =

Sampling variance in observed population vectors | ,

Environmental stochasticity

∗ Bernoulli |

∗ Bernoulli|

Population growth process ∑ ∗ ∗ ∗ ∑ ∗ ∗

where Nt is the total population size at time t (Mills 2012). We set the initial population

size 800, approximating the argali population at INNR (Wingard et al. 2011).The general joint posterior for the IPM can be written as

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Pr(, , | , ,,,,,, ,,, ,,,,,,,,,,,,) ∝

Multistate mark-recapture process and data models Pr( | , ,,,,,, ,, ,,,,,,)

Skulls process and data models * Pr( | )

Retroactive population process and data models * Pr( | , , )

Stochastic population growth process and data models * Pr(| , , , , , ,)

Priors for survival and reproduction * Uniform| 0.94, 1 ∗ ,,| 0, 10 * Logistic| ,,, ∗ Logistic| ,,, * Logistic| , ∗ Uniform| , * Logistic| ,,,

Priors for parameters and process variance in survival * | 0, 100 ∗ | 0, 10

Priors for detection and state transitions * Uniform | 0, 0.5 ∗ Uniform | 0.5,1 * Uniform, | 0, 0.1 ∗Uniform,,,′ | 0,1

We calculate lower level elasticities (Wisdom et al. 2000) for each vital rate by regressing each vital rate against λs over all MCMC samples. Since λs is calculated from

multiple years of vital rates, for each vital rate we calculate the mean over all 11 years

and then correlate the mean vital rate against λs.

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Section II. Estimating effect of livestock reduction on λs

A. (Method 1) Sample Lefkovitch matrices from before compared to after livestock

reduction

The first method uses the approach presented in Section (I). The only difference is

that instead of sampling from all 11 years of Lefkovitch matrices, we instead establish

two separate populations and project one forward using only Lefkovitch matrices from

before livestock reduction whereas we project the second population with matrices from only after livestock reduction. For each population we track λs and then subtract the two lambdas to calculate an overall difference, λdiff = λbefore - λafter.

We emphasize that this approach ignores environmental variation. Consequently we expect to find a difference only if livestock reduction had stronger effect on λ than environmental variation. In addition, NDVI was higher in the years before livestock reduction than in the years after, and we therefore expect that this method underestimates the actual effect of livestock reduction. The advantage of this method is that it incorporates vital rate covariation by drawing entire Lefkovitch matrices.

B. (Method 2) Sample NDVI values and predict vital rates before and after livestock

reduction

Recall that in the first part of the IPM, which estimates vital rates, we include

both NDVI and livestock reduction as explanatory variables for newborn survival, lamb

survival, and reproductive rate:

logit , ∗NDVI ∗livestock ,

logit , ∗NDVI ∗livestock ,

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logit ∗NDVI ∗livestock ,

Here, in each simulated year we sample observed NDVI values and use them to predict the value of each vital rate with and without livestock reduction. In other words we use the above equations to calculate each vital rate from a set NDVI value, with

LivestockRed = 0 for populations without livestock reduction and LivestockRed = 1 for populations with livestock reduction. We then use these vital rates to construct new

Lefkovitch matrices, tracking separate populations with and without livestock reduction.

Note that we do not include livestock reduction or NDVI as explanatory variables for adult survival; neither factor predicts adult survival. In building Lefkovitch matrices, we instead use the estimated adult survival rate in the year with the sampled NDVI value.

Although adult survival varies between years, in any given year adult survival is the same for populations with and without livestock reduction – even though all other vital rates differ. Consequently this formulation accounts for NDVI-driven covariation between adult survival and other vital rates, but it does not account for covariation driven by livestock reduction. If vital rate covariation is mostly positive, then this method underestimates effect of livestock reduction; on the other hand if vital rate covariation is mostly negative, then this method overestimates effect of livestock reduction. Generating random correlated vital rates is relatively straightforward in program MATLAB (Morris

& Doak 2002 Box 8.10) but requires extracting the complete set of eigenvalues and eigenvectors via the eigen() function, which is not a function that has been implemented in program JAGS.

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C. (Method 3) Life stage simulation analysis

We therefore conduct the third and final analysis outside the MCMC simulations,

instead using MCMC results to inform a life stage simulation analysis (Wisdom et al.

2000; Johnson et al. 2010b; Mills 2012). The analysis randomly generates vital rates

based on their means and correlations, incorporating both within-year correlations and

cross-correlations between years. To run the life stage simulation analysis, we use R code

from Stubben et al. (2016, ‘vitalsim’ function in the ‘popbio’ R package), which

translates MATLAB code from Box 8.10 of Morris & Doak (2002), drawing 10,000

iterations.

We simulate outcomes with and without livestock reduction by running the life

stage simulation analysis twice: once with vital rates predicted with livestock reduction,

and once with vital rates predicted without livestock reduction. Similar to Method 2, we

provide different means and variance for , , and R based on their expected values from Equations (2). We provide identical within-year and cross-correlations and same means and variance for and in both models, and then compare stochastic λ. We

calculated within-year correlations and 1-year cross-correlations using methods in Morris

& Doak (2002, p. 290), averaging correlations from all A matrices generated by MCMC

sampling.

We analyzed vital rate sensitivity and elasticity using two methods. First, we

regressed each vital rate on λs across all MCMC samples and used the slope as the

sensitivity for each vital rate (Wisdom et al. 2000). Second, we estimated vital rate

elasticity using the ‘vitalsim’ function by simulating a one at a time 5% proportional

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increase in each mean vital rate while maintaining vital rate variances, and measured changes in λs (Johnson et al. 2010b).

RESULTS

Improved vital rate estimates

The IPM improved parameter estimates for all vital rates, reducing standard error uncertainty for all vital rates compared to results from mark-recapture data of telemetry data alone. Year-to-year variation in survival of all age classes also decreased in the IPM relative to stand-alone mark-recapture estimates, effectively smoothing fluctuations and reducing extreme values (Figure 5.4). Last, the IPM calculated yearly variation in yearling survival, whereas our telemetry data was too sparse to allow any temporal variation.

Covariation between vital rates

Within-year correlations for survival were all positive, such that survival of all ages classes tended to be higher in some years. Correlation between newborn and lamb survival was particularly high (0.79), which is expected since these vital rates are partly measured from the same individual animals. In contrast, reproductive rate was negatively correlated with survival of all age classes (Appendix 5.1).

Vital rate sensitivities and elasticities

By regressing each vital rate on λs we found that vital rate sensitivity increased with age class, such that adult survival had highest sensitivity (slope = 1.06) followed by

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yearling survival (slope = 0.46), lamb survival (slope = 0.35), newborn survival (slope =

0.01) and reproductive rate (slope = 0.01; Figure 5.5).

Manually adjusting each vital rate one at a time by 5% yielded somewhat

different results (Table 5.1). Adult survival had by far the highest elasticity, increasing λs by 4.1%, which is similar to what sensitivity analysis showed. Elasticity for all other vital rates were similar, each changing λs by 0.5 – 0.7%.

Effect of livestock reduction on vital rates

Livestock reduction significantly increased newborn and lamb survival and simultaneously decreased variance in these parameters. For newborns, livestock

reduction predicted an increase in survival of 0.224 (95%CrI: 0.075 – 0.393) from 0.464

survival pre- to 0.688 survival post-reduction. Livestock reduction predicted lamb

survival from age 1 month to 12 months to increase by 0.341 (95%CrI: 0.160 – 0.469),

from 0.401 survival pre-reduction to 0.745 survival post-livestock reduction. Multiplied together, juvenile survival from birth to 12 months increased from 0.186 to 0.512 following livestock reduction. Two explanatory variables – livestock reduction and

NDVI in May – explain the vast majority of year-to-year variation in both newborn and

lamb survival (Figure 5.6).

Livestock reduction did not affect other vital rates, including reproductive rate

and adult survival. We incorporated livestock reduction and NDVI as explanatory

variables for reproductive rate, but β for neither factor differed significantly from 0

(βLiveRed = -0.27, 95%CrI: -0.88 – 0.30; βNDVI = 2.67, 95%CrI: -9.63 – 18.77). We

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previously tested for livestock reduction and NDVI effects on adult survival and found no associations (Chapter 4).

Stochastic population growth

Over the entire eleven year period 2003-2013, the IPM estimated λs = 0.957 (95%

CrI: 0.898 – 1.008), with 94.9% of MCMC simulations showing negative population

growth. However, λs increased sharply after livestock reduction. Livestock reduction

increased λs by 0.07 – 0.09, depending on what method we used to calculate differences.

If we don’t control for environmental differences before versus after livestock reduction,

and estimate λs by simply drawing transition matrices A from pre- versus post- livestock reduction (Method 1 described in Section IIA above), λs increased by 0.075 (95%CrI:

0.036 – 0.111). Alternately, if we account for variation in NDVI but not vital rate

covariation (Method 2 described above in Section IIB), λs increased by 0.071 (95%CrI: -

0.001 – 0.181; Figure 5.7). Accounting for both environmental variation and vital rate

covariation (Method 3 in Section IIC) resulted in λs difference of 0.093 (95%CI: 0.032 –

0.151), with λs rising from 0.91 pre-reduction to 1.00 post-reduction.

Prior to livestock reduction all three methods found λs = 0.91, which increased to

λs ≈ 0.99 after livestock reduction. Post-livestock reduction, population growth was

positive (λs > 1) in 30-57% of simulations, depending on the method used (Table 5.2).

DISCUSSION

Livestock reduction increased argali newborn and lamb survival, which resulted

in population growth increasing by approximately 9% per year after accounting for both

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environmental differences and vital rate covariation. Prior to livestock reduction,

population growth was almost certainly declining: 99.7% of MCMC simulations

produced λs less than 1, with a median value of 0.91. After livestock reduction, population

growth was approximately stable, though Methods 1 and 2 produced more pessimistic

outcomes (~30% probability of an increasing population) than Method 3 (57%

probability of an increasing population). Given higher NDVI pre- than post- livestock

reduction, and the preponderance of positive correlations between survival rates, we are

not surprised that Methods 1 and 2 yielded lower population growth post-livestock

reduction than Method 3. Nonetheless, our most optimistic population model yields 43%

probability that the argali population is in decline post-livestock reduction. INNR has

been subject to 20 years of conservation efforts and was recently lauded by United

Nations Development Program as a model for protected areas in Mongolia (Sarmento &

Reading 2016), and still the argali population is tenuous.

That said, three lines of evidence suggest that true population growth is probably

higher than we estimate. First, we allowed more variation in yearling survival than

probably occurs in reality by allowing yearling survival to fall as low as lamb survival

(discussed in detail below). Annual variation in high-sensitivity vital rates decreases λs

(Pfister 1998), and that effect is particularly pronounced in our model because by constraining we effectively allowed the floor for yearling survival to vary

while the ceiling remained relatively constant. Second, we estimate apparent survival, not

true survival, since animals that permanently emigrate appear as deaths. Argali at INNR

occasionally emigrate to nearby areas, and that process negatively biases our survival

estimate. Adult and yearling survival have high sensitivity, meaning that even low

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emigration rates in these age classes affects our estimate of λs. Third, incorporating survival data from skulls lowered our estimate of adult survival by 0.01 annually, which also reduced λs by 0.01 (as expected since adult survival sensitivity = 1.06). Data from

skulls may have violated important assumptions of constant population growth rate, and arguably these data should therefore not have been included. We believe skull data add information, but acknowledge that incorporating them decreased our estimate of λs.

Incorporating multiple datasets substantially improved the population model.

Uncertainty in parameter estimates decreased compared to results from single analyses in isolation. Equally importantly, the IPM appeared to isolate process variance from observation variance. Year-to-year variance decreased for all survival rates compared to results from only the mark-recapture survival analysis, and reduced extremes to effectively smooth the data (Figure 5.4). These effects are expected from incorporating independent datasets, which reduces observation variance (Schaub & Abadi 2011). One outcome of this process, which we did not anticipate, is that the IPM predicted a weaker effect of livestock reduction on vital rates than did mark-recapture analysis in isolation.

The IPM reduced negative extremes, which all occurred pre-livestock reduction, and simultaneously reduced positive extremes, which all occurred post-livestock reduction.

Consequently, the IPM estimated that livestock reduction increased lamb survival by 0.34 whereas mark-recapture survival estimated that livestock reduction increased lamb survival by 0.64. The IPM removed sampling error, which was especially apparent in parameter estimates of newborn survival. The IPM found much closer association between newborn survival and NDVI plus livestock reduction than did the mark- recapture analysis, indicating that the IPM reduced sampling error. Bayesian analyses

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take much longer to complete than frequentist analyses, but their flexibility to incorporate

numerous analyses into a single model yields substantial advantages. The time costs for

Bayesian analyses are also miniscule compared to the time required to collect multiple

years of field data.

We found that yearling survival had fairly high sensitivity (second highest after

adult survival), but we did not have enough telemetry data to accurately estimate this

parameter. That is an unfortunate combination, and is the weakest aspect of our dataset.

We could partially adjust for this weakness by constraining yearling survival to fall between adult and lamb survival in the priors, which salvaged the problem to some extent and again shows the versatility of a Bayesian approach. Nonetheless we have no direct measure of annual variation in yearling survival, and our parameterization allowed yearling survival to vary to the same extent as lamb survival. In reality yearling survival probably varies less, and is consistently higher, than lamb survival, meaning that our parameterization allowed excessive variation in yearling survival. Furthermore, that variation probably biased yearling survival low because the ceiling (adult survival) was relatively constant whereas the floor (lamb survival) had high variance.

Positive correlations between survival of different age classes probably reflect resource availability in a given year, although correlations between survival of yearlings and other age classes is in part an artifact of how we parameterized yearling survival.

Positive correlations tend to amplify year-to-year variation and thus increased the effect of NDVI and livestock reduction; negative correlations between reproductive rate R and survival rates conversely dampen these fluctuations. We found negative correlations

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between R and survival rates, which may indicate that argali females experience tradeoffs

between investing in survival versus reproduction.

We found strong evidence that the argali population at INNR is affected by

bottom-up forces. NDVI plus livestock reduction explained nearly all the variation in

cohort survival for both lambs and newborns. For each 0.01 change in NDVI reading in

May, both newborn and lamb survival increase by 0.05. We can estimate effects on λs by multiplying these changes by the sensitivity of each vital rate (slope = 0.01 and 0.35 for newborns and lambs respectively). We therefore estimate that each 0.01 increase in

NDVI increases λs by an average of 0.018. As an alternate approach, we also built A

matrices for each year using median estimates for each vital rate and then calculating

asymptotic λ for each year. The general linear model:

∗ ∗

predicts livestock reduction to increase λ by 0.103, and predicts each 0.01 increase in

May NDVI to increase λ by 0.019 (Figure 5.8). Our point here is that we expect even

small changes in NDVI to affect λs, which suggests that the argali population is affected

by bottom-up forces. And if the argali population is affected by bottom-up forces, it is

susceptible to forage competition with livestock.

Indeed, we found strong effects of livestock reduction on argali population

growth. Results from the IPM provide the third, and strongest, line of evidence that

livestock detrimentally affect argali. We had previously shown that livestock reduction

increased argali birth mass (Chapter 3) and that livestock reduction increased survival of

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newborns and lambs (Chapter 4). With the IPM we demonstrate that these effects

translate to population growth. Argali population growth increased by 9% per year following a 40% livestock reduction in the core zone. Furthermore, our study design underestimate true effects of livestock because we (1) reduced but did not fully remove livestock, and (2) reduced livestock in only a relatively small area representing about

one-quarter of occupied argali habitat.

A key advantage of our study design is that it tests the efficacy of a common management strategy, core zones. Our results are unambiguous that livestock reduction in the core zone at INNR has strong positive effects on argali. We recommend that core zones should be a key management tool for maintaining native biodiversity alongside high livestock densities in Central Asia. However, we caution that core zones need to be designated such that they encompass important areas for wildlife. At INNR, the core zone was identified as important argali habitat following nearly 10 years of biological surveys.

Although core zones have been implemented in numerous protected areas in Central Asia

(Kaczensky et al. 2008; Suryawanshi et al. 2010; Li et al. 2014), many appear to be designated to simply encompass an inner portion of a protected area without much information about the area’s importance to wildlife. For example, core zones in several protected areas in China do not encompass important habitat for snow leopards (Panthera uncia; Li et al. 2014). Haphazardly located core zones will probably not be as effective as the core zone at INNR. Livestock are abundant in protected areas across Central Asia

(Berger et al. 2013). We provide empirical evidence that when livestock are reduced inside small but biologically important areas, native herbivores benefit.

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Table 5.1 Vital rate sensitivities and elasticities. We calculated sensitivity as the slope from regressing each vital rate on λs from each MCMC sample. We also manually increased each vital rate one at a time by 5% to determine its effect on λs after projecting the population 20 years into the future; the first row shows λs of the baseline population, and each subsequent row shows the effect on λs

Vital rate Sensitivity λs Absolute Percent

(Slope) change in λs change in λs

(Baseline population) - 0.972 - -

0.01 0.978 0.006 0.6%

0.35 0.978 0.006 0.6%

0.46 0.977 0.005 0.5%

1.06 1.012 0.039 4.1%

0.01 0.979 0.007 0.7%

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Table 5.2 Stochastic population growth (λs) pre- and post-livestock reduction as calculated using three methods. Last column indicates the percent of simulations with λs > 1 post- reduction.

Analysis λs Pre λs Post Probability (95%CrI) (95%CrI) λ > 1 s-post Method 1 0.912 0.986 30

(0.85-0.96) (0.94-1.04)

Method 2 0.910 0.988 33

(0.82-0.98) (0.93-1.04)

Method 3 0.909 1.003 57

(0.86-0.96) (0.97-1.04)

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Figure 5.1 Components of the integrated population model.

Livestock Multistate mark‐recapture survival reduction Movement Detection off/on study NDVI probabilities area

Collar Double S S S S failure counting Repro Newb Lamb Yearlg Adult

Age Capture ratios histories Retroactive population model

Skulls Binomial

R*Sn Lambs 00 Analysis *Sa Explanatory variable Yrlngs Sl 00 Parameter Adults 0 Sy Sa Data s Nuisance parameter Stochastic population model

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Figure 5.2 Retroactive population model that predicts observed population vectors (bold

boxes) during 2003-2014 using survival rate parameters (blue circles) estimated from

telemetry and skulls. The model incorporates two time steps each year: a 2-month time

step from March 1 – May 1 that incorporates the birth pulse modeled to occur on April 1, and a 10-month time step from May 1 – March 1. Vital rate parameters depicted are per capita number of female lambs given birth to by an average adult female (reproductive rate R), newborn survival (Sn), lamb survival (Sl), yearling survival (Sy), and adult survival (Sa), which are placed in the transition matrix . All survival rates are monthly probabilities, meaning that survival probability over the 10 months from May to March is

and over the 2 months from March to May is . Observed population vectors

relate to true population vectors via ~ ,, where is sampling variance.

0 0 ∗ 0, 0 ∗

00 ∗ 0, 0 ∗

0 0 ∗ 0, 0 ∗

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Figure 5.3 Lefkovitch matrix (A) and population vector (n) used in stochastic population model. R = reproductive rate, Sn = newborn survival, ySl = 11-month lamb survival, ySy

= year-long yearling survival, ySa = year-long adult survival.

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Figure 5.4 Parameter estimates and standard errors (bars) for vital rates calculated from mark-recapture analysis of telemetry data compared to results of the Integrated

Population Model, which incorporates additional data sources.

Adult survival

Mark-recapture estim 0.6 0.7 0.8 0.9 1.0 IPM es timate

2002 2004 2006 2008 2010 2012 Lamb survival

Mark-recapture estim IPM es timate 0.0 0.2 0.4 0.6 0.8 1.0

2002 2004 2006 2008 2010 2012 Newborn survival

Mark-recapture estim IPM es timate 0.2 0.4 0.6 0.8 1.0

2002 2004 2006 2008 2010 2012

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Figure 5.5 Sensitivity analysis for lower level vital rates. Slope of the regression is

2 sensitivity, and r shows how much of the variation in λs each vital rate explains.

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Figure 5.6 (a) Argali newborn and (b) lamb survival at Ikh Nart Nature Reserve,

Mongolia, in relation to NDVI and livestock reduction.

(a) survival month - 1

Newborn survival Newborn Livestock reduction

NDVI in prior May ear 0.13 0.15 0.17 0.19 y 0.0 0.2 0.4 0.6 0.8

2002 2004 2006 2008 2010 2012 rior p 9 y (b) NDVI on Ma on NDVI survival annual

Lamb Lamb survival Livestock reduction NDVI in prior May 0.13 0.15 0.17 0.19 0.0 0.2 0.4 0.6 0.8

2002 2004 2006 2008 2010 2012 Year

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Figure 5.7 Histograms of MCMC simulations showing effect of livestock reduction on stochastic population growth (λs) as calculated using two techniques described in

Methods Section IIA (Method 1) and Section IIB (Method 2). In the bottom diagram the arrow points to 0, representing no change in population growth following livestock reduction.

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Figure 5.8 NDVI in May in relation to asymptotic λ corrected for livestock reduction (r2

= 0.90, slope = 1.92, p = 0.0002).

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Appendix 5.1 (a) Within-year correlations and (b) one-year cross-correlations between argali vital rates at Ikh Nart Nature Reserve, 2003-2013. Sn = 1-month newborn survival, ySl = annual lamb survival, ySy = annual yearling survival, ySa = annual adult survival, R

= reproductive rate.

(a) Sn ySl ySy ySa R

Sn 1.0

ySl 0.787 1.0

ySy 0.539 0.717 1.0

ySa 0.034 0.097 0.223 1.0

R -0.323 -0.201 -0.182 -0.108 1.0

(b) Sn ySl ySy ySa R

Sn 0.462 0.511 0.400 0.073 -0.520

ySl 0.300 0.415 0.341 0.090 -0.501

ySy 0.189 0.282 0.147 0.047 -0.358

ySa 0.006 0.067 0.034 -0.086 -0.031

R -0.035 -0.089 -0.068 -0.012 0.315

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CHAPTER 6

USING GROUP COMPOSITIONAL DATA TO IMPROVE

UNGULATE POPULATION MONITORING IN CENTRAL ASIA

L. STEFAN EKERNAS, University of Montana, Wildlife Biology Program, College of

Forestry and Conservation, Missoula, MT 59812, USA

GANCHIMEG J. WINGARD, Denver Zoological Foundation, Conservation and

Research Department, Denver, CO 80205 USA

SUKH AMGALANBAATAR, Argali Wildlife Research Center, Ulaanbaatar, Mongolia

RICHARD P. READING, University of Denver, Department of Biology & Graduate

School of Social Work, Denver, CO 80208 USA

JOEL BERGER, Wildlife Conservation Society, Bronx, NY 10460 USA & Colorado

State University, Fisheries, Wildlife, and Conservation Biology, Fort Collins, CO

80523 USA

ABSTRACT

Central Asia harbors a diverse array of ungulates threatened by overharvest, burgeoning livestock populations, and habitat loss. Exacerbating these threats is an absence of tenable methods to reliably monitor ungulate population growth, undermining managers’ ability to identify at-risk populations or evaluate conservation interventions. However, researchers have recently developed an effective low-cost monitoring tool: female:young age ratios, which can accurately estimate population growth when adult survival is known. Age ratios are amenable to participatory monitoring by local communities, which

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is common in the region, because data can be collected on diverse terrain with little

training, minimal equipment, and without the need for time-intensive systematic surveys.

Age ratios provide detailed information on population growth, and thus complement

methods that estimate population size – such as double observer counts, distance

sampling, and mark-resight. Here, we highlight key points for properly designing age

ratio surveys. Next we expand on current knowledge by demonstrating how to broadly

infer population growth from age ratios when information on adult survival is incomplete, using a case study of argali (Ovis ammon) spanning 12 years. For argali, we

suggest a rule of thumb whereby lamb:ewe ratios below 0.37 likely indicate a declining

population. As a practicality, age ratios can immediately improve monitoring for six

ungulate species native to Central Asia for which survival estimates have been published.

Telemetry is the best method for estimating ungulate survival, and telemetry data are available from another nine species in the region – eight of which are threatened with extinction. Calculating survival for these species would unlock new avenues for meaningfully engaging local communities, improve monitoring, and enable researchers and associated governments to quantitatively evaluate population trends.

INTRODUCTION

Knowledge about population trend is critical for species conservation. A fundamental challenge to conservation in developing countries is that resources are scarce while methods for reliably estimating population trends are expensive. In Central

Asia, this challenge is exacerbated by mountainous terrain, lack of scientific training, low population density of many native species, and poor infrastructure for aerial surveys.

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Owing to these obstacles, methods that can accurately estimate ungulate population trend are largely unfeasible (Singh & Milner-Gulland 2011). Central Asia harbors a diverse array of endemic ungulates, and developing accurate low-cost population monitoring methods is considered a “high priority” for conservation (Schaller 1998; Mallon et al.

2014).

Several methods have recently been advanced to address ungulate population monitoring in Central Asia, but all have serious limitations. Mark-resight and distance sampling estimate population abundance but are generally too imprecise to yield much information on population trend (Young et al. 2010; Wingard et al. 2011). Double- observer ground counts work well when entire valleys are visible from a ridgeline

(Suryawanshi et al. 2012), but they are unsuitable to the rolling hills common to Central

Asia’s deserts and steppes where viewsheds are small and skittish animals run from observers, meaning that two observers separated spatially or temporally cannot reliably detect the same animal groups. Presence/absence data are simple to collect but have limited power to estimate population growth in most circumstances even when coupled to sophisticated patch occupancy models (Singh & Milner-Gulland 2011). Genotyping feces or other biological material and estimating population size with mark-recapture methods has been successfully used in Central Asia (Harris et al. 2010), but costs are prohibitive for use in long-term monitoring. Aerial surveys would be useful, but these are generally not available due to high costs, government prohibitions, and because most of the region has neither airplanes, airstrips, nor aviation fuel.

Instead, we suggest using young:female age ratios. Researchers have for decades used age ratios to estimate recruitment in ungulate populations, but translating this

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estimate into population growth is difficult because age ratios are a function of multiple

vital rates including fecundity, adult survival, juvenile survival, age of first reproduction,

and age structure of the population (Caughley 1974; McCullough 1994; Harris et al.

2008). However, DeCesare et al. (2012) – building on work by Hatter & Bergerud (1991)

-- show that recruitment R (measured with age ratios) can accurately estimate population

growth over the prior year when adult female survival S is known:

Equation 1 1

Female:young age ratios are relatively simple to collect and more robust to error

than other available methods, which is important for participatory monitoring in Central

Asia where field data collectors typically have little or no scientific training, no

specialized equipment, and varying degrees of motivation. For age ratios, data collectors

do not need to systematically follow transects or other rigid sampling schemes, and they

do not need any specialized equipment (e.g. GPS, compass, or rangefinder) beyond

binoculars. Pastoralists can therefore collect data while herding livestock without needing

to set aside blocks of time exclusively for data collection. Age ratios are also more robust

to variation in group-specific detection probability – both across the landscape and

between observers – than distance sampling, mark-resight, and double-observer counts,

all three of which explicitly assume equal detection probability across the landscape

and/or observers (Thomas et al. 2009; McClintock 2012; Suryawanshi et al. 2012). In

contrast, age ratios need to come from a representative sample of the population, but

systematic differences in detection probability do not inherently bias the results by

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violating foundational assumptions. Age ratios can therefore substantially improve

ungulate monitoring in Central Asia when information on adult female survival is

available.

The primary challenge with ‘age ratios and survival’ monitoring is that estimating

ungulate survival requires capturing, collaring, and tracking animals via telemetry, which

is expensive and logistically complex (Mills 2012). Age ratios are consequently most

useful for species in Central Asia where data on adult survival already exist or can be

collected. An additional challenge is that observers must avoid misclassifying young of

the year as yearlings (and vice versa), so observers should be trained to minimize these

errors

Here, we provide an overview of the age-ratio monitoring model, focusing on the

practical aspects of what data to collect, when to conduct surveys, and key points for

properly calculating population growth rate from field-collected age ratios. In addition,

we demonstrate how to use age ratios to infer population trend when survival data are incomplete, using a detailed case study from argali (Ovis ammon).

THE MATHEMATICAL MODEL

We provide an overview of the mathematical model, and refer readers to

DeCesare et al. (2012) for a detailed description including methods for using age ratios to build matrix models. The core equation estimates population growth (λ) in a given year

based on adult female survival (S) and recruitment (R):

Equation 1 1

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Survival S for adult female ungulates is typically calculated from capturing, radio-

collaring, and tracking individual animals (Millspaugh & Marzluff 2001). Recruitment

(R) is measured as the number of juvenile females (njf) per number of females (nf) at the end of the biological year immediately before a new cohort of juveniles is born to incorporate annual mortality. However, data collected in the field is typically the age ratio (X) of the number of juveniles (nj) per number of adult females (naf),

Equation 2

The age ratio must be adjusted to count only juvenile females, which means X

should be halved if we assume a 50:50 lamb sex ratio. Furthermore recruitment R is

correctly measured as juveniles per all females (adults+juveniles), not juveniles per adult

females (DeCesare et al. 2012). We therefore calculate R from the field-collected age

ratio X in the following manner:

0.5 Equation 3 1 0.5

where ~N(0, σ2) and σ2 is calculated from resampling group observations via a bootstrap

or other similar procedure (Chapter 5).

Key points for designing monitoring surveys

169

Age ratio data X should be collected immediately before the pulse birth to account for overwinter mortality. For example in argali the birth pulse occurs in April, meaning that March is the optimal time to survey age ratios. Surveys conducted at other times of year fail to account for overwinter lamb mortality and thus provide an inflated recruitment estimate.

Yearling females – which at the time of surveys are about to turn 2 years old

– are counted with adult females and included in the denominator of X in Equation

(2) even if yearlings do not reproduce. A main advantage of Equation (1) over matrix

models is that we can calculate λ with no knowledge about the age of first reproduction.

However, Equation (1) assumes yearlings have similar survivorship to adults. If yearlings

have lower survival than adults, consecutive years of age ratio data are needed to calculate the age structure of the population and build appropriate matrix models

(DeCesare et al. 2012). Age ratios that do not include yearlings in the denominator inflate recruitment estimates.

An important point is that Equation (1) measures transient population growth rate over the previous year. Transient population growth provides an accurate year-to-year measure of growth even for populations that are not in stable age distribution, but the downside is that yearly population growth may not reflect long-term trends. Surveys over multiple years are thus required to identify long-term trends, and long-term population growth can be calculated with the geometric mean of λ from multiple

years (DeCesare et al. 2012).

CASE STUDY: MONITORING ARGALI WITH LIMITED SURVIVAL DATA

170

Background

Argali, the world’s largest wild sheep, inhabit the mountains, steppes, and deserts of Central Asia from southern in the north to the Indian Himalaya in the south.

Nine subspecies are usually recognized (Geist 1991). IUCN classifies the species as Near

Threatened, though some subspecies are at greater risk of extinction, and populations are declining nearly everywhere as a consequence of overharvest and competition with abundant livestock (Harris & Reading 2008). Reducing both harvest and livestock competition are critical to maintaining stable argali populations, but conservation efforts are hampered by lack of effective monitoring methods (Mallon et al. 2014).

Monitoring age ratios and survival via Equation 1 has potential to improve argali conservation. However, a key challenge is that argali adult survival is known from only a single site – Ikh Nart Nature Reserve (INNR) in central Mongolia’s Gobi steppe (Figure

6.1). Survival presumably varies between sites, especially for argali with different

subspecies and potentially different life history strategies. Therefore we cannot assume

adult survival at INNR applies to other sites.

Nonetheless, survival data from INNR informs argali monitoring at other

locations. INNR is a strategically useful site because argali adult survival over the long

term is probably higher at INNR than elsewhere and thus represents a maximum. Three lines of evidence support this assumption. First, argali populations are declining nearly everywhere across their range except in central Mongolia surrounding INNR, where

populations are increasing (Harris & Reading 2008; Mallon et al. 2014) and colonizing

new habitats (R.P.R. unpublished data). These trends contrast directly with other regions

of argali range, where populations have been extirpated from sites they inhabited in the

171

recent past (western China and : Schaller & Kang 2008; northern China: Harris

et al. 2009). Second, argali management and conservation activities at INNR have been

particularly successful, whereas most argali populations have no management or

conservation program. Indeed, in 2010 the United Nations Development Program designated INNR as a model Mongolian protected area for its effective and collaborative management. Poaching has been nearly eliminated and local pastoralists are highly supportive of argali conservation at the site (Sarmento & Reading In Press). Also, management strategies in the form of a core zone have demonstrably increased argali vital rates and population growth (Chapters 4, 5). Third, limited empirical data on skull- derived age-specific mortality from different sites and subspecies suggest high argali survival at INNR. Skulls of male Marco Polo argali O.a. polii in far western China (n =

136) and Tibetan argali O.a. hodgsoni on the Tibetan plateau (n = 59) both have median age at death of ~6 years with max age of 10 (Schaller 1998, p. 91), whereas skulls of male Gobi argali O.a. darwini collected at INNR have median age at death of 8.5 years with max age 14 years (n = 71; L.S.E., G.W., R.P.R., S.A., & K. Fitzgerald unpublished data).

For these reasons we make the assumption that long-term adult argali survival at

INNR lies near a ceiling that other sites may attain but likely not surpass. As we explain below, this assumption allows us to make inferences about population growth using age ratios from any site in argali range.

Survival, recruitment, and argali population growth at INNR

Methods

172

Four years after INNR was established as a protected area in 1996, we commenced a long-term research project on argali. We have captured argali of all age-sex classes, fitted them with VHF, GPS, and/or satellite collars, and tracked them via

telemetry since 2002 (Kenny et al. 2008). Denver Zoological Foundation, Mongolian

Academy of Sciences, Argali Wildlife Research Center, and Mongolian Conservation

Coalition conducted captures using methods approved by Mongolian Academy of

Sciences. Researchers spent at least two weeks each month tracking collared animals, classifying individuals as alive, dead, or not seen. Our dataset spans 136 months,

September 2002 through December 2013. In 2006, INNR’s director (S.A.) reduced human and livestock density by 40% inside a core zone of key argali habitat (Ekernas et al. In Press). To demonstrate age ratios’ effectiveness in evaluating a conservation action, we calculated long-term population growth both before and after livestock reduction in the core zone.

We collected 6,332 animal-months of survival data from 184 individual argali,

with 3,200 animal-months of survival data from 49 adult females. We used these data to estimate yearly adult female survival at INNR in a Bayesian multi-state parameterization of a joint live-dead mark recapture analysis, which includes both live re-sightings and dead recoveries (Chapter 4). To improve parameter estimates, we incorporated additional analyses into an integrated population model, and here use results from that model

(Chapter 5). We assume adult survival at INNR represents the maximum long-term survival rate for any argali population.

Results

173

For adult females, we found a random-effect mean annual apparent survival of

0.844 ± 0.016 (SE). During individual years, adult survival estimates ranged from 0.83 to

0.87 and did not change after livestock reduction. Recruitment, on the other hand, did

increase after livestock reduction. We used these data to calculate transient and long-term

population growth rate for argali at INNR from 2002-2013 using Equation (1). We also

compared argali population growth before and after livestock reduction by calculating the

geometric mean survival and recruitment during the corresponding years, although we

note that this before-after comparison does not account for environmental differences

before versus after livestock reduction. Using this simple comparison we estimate that

livestock reduction increased long-term argali population growth by 5.0% annually from

pre-treatment mean 0.967 to post-treatment mean 1.017 (Table 6.1, Figure 6.2).

Using argali survival at INNR to inform population monitoring at other sites

INNR is the only site with high-quality data on argali survival. Nonetheless, we

can make broad inferences about argali population growth at any site based only on pre-

birth pulse age ratios if we assume that adult argali long-term survival is maximized at

INNR. When we insert adult survival from INNR ( = 0.844) as a ceiling on the contour

plot of Equation 1, everything above that horizontal line effectively disappears since we

consider it biologically implausible (Figure 6.3). If long-term adult survival is never

higher than 0.844, then the lamb:ewe age ratio must be at least X* = 0.37 to have a stable or increasing population, since that is where = 0.844 intersects the isocline for λ = 1.

Therefore, lamb:ewe ratios less than 0.37 (1 lamb per 2.7 ewes) likely indicate a declining population. Pre-birth pulse age ratios above 0.37 do not necessitate positive

174

population growth, since we don’t know argali adult survival at locations other than

INNR, but positive growth is increasingly likely the higher the lamb:ewe ratio. To

simplify how managers can interpret age ratios, we classify three general categories

based on these boundaries: age ratios below 0.37 likely indicate a declining population

(shaded red in Figure 6.3), between 0.37 – 0.55 indicate an approximately stable

population (shaded gray), and above 0.55 indicate an increasing population (shaded

green). These rules of thumb are similar to management recommendations for bighorn

sheep (Ovis canadensis), whereby populations are considered “non-healthy” if they have

consecutive years with lamb:ewe ratios below 0.2 (Western Association of Fish and

Wildlife Agencies 2015).

We advise two caveats to these inferences. First, age ratio data collected over

multiple years will provide much stronger conclusions than data from only one or a few

years. Our three categories primarily hold for lamb:ewe ratios collected over multiple

years. Equation (1) measures transient population growth over the prior twelve months,

so multiple years of data are needed to draw conclusions about long-term population

growth even with perfect information on annual survival. More pertinently to argali

where we only have data from INNR, at other sites adult survival in any individual year may be higher than the long-term mean at INNR; however, over the long term we expect lower or at best equal survival at other locations. Consequently, we can draw stronger inferences from data collected over multiple years. Second, boundaries between the green, gray, and red sections in Figure 6.3 should not be viewed as definitive but should instead be treated as rules of thumb to accommodate for uncertainty in both survival and

recruitment stemming from sampling and process variance alike. Our measure of adult

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survival at INNR has uncertainty (SE = 0.016), which translates to X* having a 95% confidence interval from 0.28 – 0.46. Compounding uncertainty due to sampling variance, process variance lowers survival in other argali populations by an unknown amount relative to INNR. Additionally, age ratio data invariably incorporate uncertainty stemming both from imperfect sampling and from observer error in classifying age classes of individual animals. Misclassifying age classes is especially problematic because it can introduce bias if certain observers systematically misclassify individual animals’ age classes. One potential way to reduce this bias is to have multiple observers classify the same animal groups and then analyze age ratios by treating “observer identity” as a random effect, which should be closer to truth if the distribution of observers’ bias is centered at 0. Despite these caveats, participatory monitoring with age ratios provides more information on population trend than other tenable methods and can complement data on abundance.

Retrospective analysis of transient argali population growth across Central Asia

Argali age ratios have been reported from multiple sites across Central Asia, and we use these data to retrospectively infer transient population growth (Table 6.2; Figure

6.1). In concurrence with IUCN and CMS assessments (Harris & Reading 2008; Mallon et al 2014), we found many instances of negative argali population growth and few instances of positive population growth. A recurring problem in the data is that researchers did not collect age ratios immediately before the birth pulse. This issue can be partially reconciled by recognizing that lambs have higher mortality rates than adult females, meaning that lamb:ewe ratios typically decrease over time until the next birth

176

pulse. Age ratios from summer, autumn, and early winter therefore represent a best case

scenario for recruitment and population growth. Since recruitment decreases by an

unknown amount during winter, age ratios collected during summer and autumn are

uninformative for population growth if the age ratio is > 0.37. However if the lamb:ewe

age ratio is < 0.37, transient population growth is likely negative regardless of when age

ratios were collected.

DISCUSSION

Incorporating age ratios into participatory monitoring represents a substantial

advancement for monitoring ungulate populations in Central Asia. For argali, age ratios

combined with adult survival at INNR provide a broad – though imprecise – estimate of

population growth from any site in Central Asia. Monitoring with age ratios complements

methods to estimate abundance, since age ratio data can be collected simultaneously with

distance sampling or double observer counts as long as these surveys are conducted

immediately before the birth pulse.

The main limitation to monitoring with age ratios is that researchers need

information on adult female survival, which is best achieved via telemetry (Millspaugh

and Marzluff 2001). Adult survival data are available from six ungulate species native to

Central Asia, and telemetry data are available from at least nine additional ungulate

species even though survival estimates, to our knowledge, have not been published

(Table 6.3; Figure 6.4). Of these fifteen species, thirteen are threatened with extinction

globally or regionally. Incorporating age ratios can immediately improve monitoring of

177

the six species with known survival, and we recommend that estimating survival should be a research priority for the nine species with telemetry data.

Estimating survival requires sustained investments in strategic populations.

Telemetry data involved low sample sizes for many of the nine species without survival estimates, while reliably estimating survival requires tracking at least 25 individuals over several years (Winterstein et al. 2001). Nonetheless, published telemetry studies demonstrate the logistic feasibility of capture operations, clearing a major obstacle.

Where telemetry is not feasible, two methods can yield information on survival.

First, we can conduct mark-recapture survival analyses for species with individually recognizable animals that are consistently re-sighted over multiple years even without telemetry. Some mountain ungulates with numerically small populations and geographically restricted home ranges meet these criteria (Hogg et al. 2006). In Central

Asia, researchers could potentially use this technique to monitor in the Indian

Kashmir (Capra falconeri; Bhatnagar et al. 2009) and some populations of blue sheep

(Pseudois nayaur; Namgail 2014). Where individuals cannot be identified, researchers can crudely estimate survival using a representative sample of skulls (Murie 1944).

Calculating survival from skulls requires making several assumptions that are often unrealistic for ungulate populations, including that population growth remains constant across years and that the population is in stable age distribution (Sinclair et al. 2006). In some cases estimates from skulls can be accurate, and known fate analysis of female argali skulls collected at INNR yielded a similar annual survival estimate ( = 0.840;

95% CI: 0.802 – 0.874; n = 62 skulls) as telemetry ( = 0.852). Nonetheless skulls yield less accurate and potentially biased estimates of survival and provide no information on

178

annual variation. Calculating survival from skulls may be appropriate when researchers

can compare results to telemetry data, otherwise we recommend using it only as a

preliminary or last resort option.

Age ratios provide a low-cost method for monitoring ungulate populations, but collecting detailed demographic data can generate substantially more information. For well-studied populations such as the argali population at INNR, age-structured population models, life stage simulation analysis, and integrated population models provide more appropriate tools for analyzing population dynamics and trajectories (Mills 2012).

Indeed, our estimates of stochastic population growth using an integrated population model (Chapter 5) produce somewhat different results compared to the methods presented here. Monitoring via age ratios alone is best suited for populations with limited demographic data.

Central Asia harbors a diverse array of globally threatened ungulates in need of monitoring to both identify populations at risk and evaluate conservation interventions.

Age ratios provide a cost effective method to monitor ungulate populations in resource-

limited settings where conservationists partner with local communities, but the method requires information on adult survival. Estimating adult survival unlocks new avenues for meaningfully engaging local communities, improves monitoring, and enables researchers to quantitatively evaluate the effectiveness of conservation actions. Calculating survival should be a research priority for ungulates in Central Asia.

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Table 6.1 Annual estimates of adult female argali (Ovis ammon) survival (S), pre-birth pulse lamb:ewe ratio (X), transient population growth rate from Equation 1 (λ), and status of livestock reduction at Ikh Nart Nature Reserve, Mongolia. We found no evidence that adult survival changed after livestock reduction and therefore use the overall random effect mean survival both pre- and post- reduction. For X and λ we report the pre- and post- geometric means.

Year S X λ Livestock

reduction

2002 0.85 0.24 0.947 Pre

2003 0.84 0.60 1.092 Pre

2004 0.85 0.32 0.987 Pre

2005 0.83 0.24 0.930 Pre

2006 0.84 0.11 0.891 Pre

2007 0.84 0.48 1.039 Post

2008 0.87 0.32 1.007 Post

2009 0.86 0.33 1.002 Post

2010 0.84 0.67 1.123 Post

2011 0.84 0.37 0.993 Post

2012 0.83 0.34 0.977 Post

2013 0.85 0.33 0.985 Post

Overall 0.84 0.281 0.996 -

Pre-reduction 0.84 0.228 0.967 Pre

Post-reduction 0.84 0.326 1.017 Post

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Table 6.2 Age ratios reported from argali populations across Central Asia with inferred population trend (λ). We can infer population trend of shaded populations but not unshaded populations where age ratios are greater than 0.35 but do not incorporate overwinter mortality.

Lamb:ewe Season Year Country Site Subspecies Inferred λ Reference

0.160 February 1979 Mongolia Altai O.a. ammon Declining 1,2

0.685 August 1979 Mongolia Altai O.a. ammon Increasing* 1,2

0.599 ? 1980-82 Mongolia Altai O.a. ammon Increasing* 1,3

0.481 Sep-Nov 1991-92 Mongolia Altai O.a. ammon Stable* 1,4

0.160 ? 1990 Mongolia Altai O.a. ammon Declining* 1,5

0.110 Aug-Sep 1993 Mongolia Altai O.a. ammon Declining* 1,5

0.420 November 2001 Mongolia Altai O.a. ammon Stable* 6

0.343 February 1979 Mongolia Altai O.a. ammon Declining 7

0.754 Summer 1979 Mongolia Altai O.a. ammon Increasing* 7

0.600 Summer 1983 Mongolia Altai O.a. ammon Increasing* 7

0.671 November 1982 Mongolia Gobi Altai O.a. ammon? Increasing* 1,8

0.263 November 2000 Mongolia Hangai O.a. ammon? Declining* 9

0.417 August 1997 Mongolia Hangai O.a. ammon? Stable* 10,11

0.631 October 1998 Mongolia Hangai O.a. ammon? Increasing* 10,12

0.478 July 1999 Mongolia Hangai O.a. ammon? Stable* 10,13

0.469 April 2009 Mongolia Multiple sites O.a. darwini Stable** 14

0.130 November 2000 Mongolia Gobi O.a. darwini Declining* 9

0.369 August 1994 Mongolia Gobi O.a. darwini Declining 1

0.750 Sep-Oct 1993 Mongolia Gobi O.a. darwini Increasing* 1,15

0.400 October 1998 Mongolia Ikh Nart N.R. O.a. darwini Stable* 16

191

Lamb:ewe Season Year Country Site Subspecies Inferred λ Reference

0.410 Summer 1987-88 China Tibetan O.a. hodgsoni Stable* 17

plateau

0.616 Summer 1991 China Qinghai O.a. hodgsoni Increasing* 18

0.625 Summer 1992 China Qinghai O.a. hodgsoni Increasing* 18

0.450 March-April 2003 India Ladakh O.a. hodgsoni Stable 19

0.310 March-April 2003 India Ladakh O.a. hodgsoni Declining 19

0.450 Multiple 2007 India Sikkim O.a. hodgsoni Stable* 20

0.380 Winter 2010 Tajikistan Pamirs O.a. polii Stable 21

0.620 Winter 2010 Tajikistan Pamirs O.a. polii Increasing 21

0.480 June-July 2003 Tajikistan Pamirs O.a. polii Stable* 22

0.460 Summer 2000 Tajikistan Pamirs O.a. polii Stable* 22

0.410 December 2010 Tajikistan Pamirs O.a. polii Stable* 23

0.602 August 2010 Tajikistan Pamirs O.a. polii Increasing* 24

0.738 ? 2003 Tajikistan Pamirs O.a. polii Increasing* 24

0.505 December 2010 Tajikistan Pamirs O.a. polii Stable* 25

0.306 December 2011 Tajikistan Pamirs O.a. polii Declining* 25

0.485 January 2012 Tajikistan Pamirs O.a. polii Stable* 25

0.100 June-July 2007 Afghanistan Big Pamir O.a. polii Declining* 26

0.045 Nov-Dec 2007 Afghanistan Big Pamir O.a. polii Declining* 26

0.104 May-July 2008 Afghanistan Big Pamir O.a. polii Declining* 26

0.43 June-July 2008 Afghanistan Big Pamir O.a. polii Stable* 27

0.233 Aug-Sep 2008 Afghanistan Big Pamir O.a. polii Declining* 28

0.66 October 2006 Afghanistan Wakhjir O.a. polii Increasing* 27

Valley

0.400 Nov+May 2005+06 China Western O.a. polii Stable* 22

0.425 July-Aug 1993 Kyrgyzstan Korunduk O.a. polii Stable* 29

* Best case scenario because age ratios do not incorporate overwinter mortality

192

** Possibly a mix of pre-birth pulse and post-birth pulse, though authors state that surveys were pre-birth pulse.

1 Reading et al. 1997 2 Dzieciolowski et al. 1980 3 Zhirnov & Ilyinksy 1986

4 Amgalanbaatar 1993 5 Luschekina 1994 6 Maroney 2003

7 Des Clers 1985 8 Davaa et al. 1983 9 Frisina et al. 2007

10 Johnson & Williams 2002 11 Frisina & Boldbaatar 1998 12 Frisina & Ulziimaa 1999

13 Frisina & Ulziimaa 2000 14 Frisina & Purevsuren 2009 15 Valdez & Frisina 1993

16 Frisina et al. 2004 17 Schaller 1998 18 Harris 1993

19 Namgail 2004 20 Chanchani et al. 2011 21 Valdez 2012

22 Schaller & Kang 2008 23 Michel & Muratov 2010 24 Moritz et al. 2010

25 Valdez et al. 2016 26 Harris et al. 2010 27 Winnie 2008

28 Habib 2006 29 Fedosenko et al. 1995

193

Table 6.3 Ungulate species native to Central Asia with published survival estimates and/or telemetry data, potentially enabling survival estimates and population monitoring via age ratios.

Common name Latin name IUCN Status in Adult Regional Ref

status Mongolia1 survival data

Argali Ovis ammon NT EN 0.84 Telemetry This study

Saiga Saiga tatarica CR EN 0.79 Telemetry 2,3

Mongolian gazelle Procapra gutturosa LC EN 0.64 Telemetry 4

Red deer Cervus elaphus LC CR 0.83-0.95* None 5-8

Moose Alces alces LC LC 0.87-0.95* None 8-10

Caribou Rangifer tarandus LC VU 0.88-0.93* None 11-13

Przewalski’s gazelle Procapra przewalskii EN - NA Telemetry 14

Goitered gazelle Gazella subgutturosa VU VU NA Telemetry 15

Chiru Pantholops hodgsonii EN - NA Telemetry 16

Siberian ibex Capra sibirica LC LC NA Telemetry 17

Takin Budorcas taxicolor VU - NA Telemetry 18

Himalayan Moschus leucogaster EN - NA Telemetry 19

Wild Camelus ferus CR EN NA Telemetry 20

Asiatic wild ass Equus hemionus NT EN NA Telemetry 21

Przewalski’s horse Equus ferus przewalskii EN CR NA Telemetry 21

* Estimates are from outside Central Asia

1 Clark et al. 2006 2 Milner-Gulland 1994 3 Berger et al. 2008 4 Olson et al. 2014

5 Benton et al. 1995 6 Sinclair 1989 7 Unsworth et al. 1993 8 Kunkel & Pletscher 1999

9 Ballard et al. 1991 10 Musante et al. 2010 11 Hebblewhite et al. 2007 12 DeCesare et al. 2012

13 McLoughlin et al. 2003 14 Hu et al. 2013 15 G.W. & R.P.R. unpub. 16 Buho et al. 2011

17 Reading et al. 2007 18 Guan et al. 2013 19 Kattel & Alldredge 1991 20 Kaczensky et al. 2014

21 Kaczensky et al. 2008 194

Figure 6.1 Sites where we use reported argali (Ovis ammon) lamb:ewe age ratios to retrospectively infer transient population growth (Table 6.2). Our study site, Ikh Nart

Nature Reserve in Mongolia, is represented by a black star; all other sites are represented by white stars. Background map courtesy of Google.

195

Figure 6.2 Contour plot of transient population growth rates (λ) from paired adult female

survival values and pre-birth pulse lamb:ewe ratios (following DeCesare et al. 2012).

Values below the λ = 1 isocline represent negative population growth, and values above it represent positive population growth.

Annual rates pre core zone Annual rates post core zone 1.3 Geometric mean pre-core zone Geometric mean post-core zone 1.2 1 .2  =1 1. 15

1. 1 05 Adult female survival (S)

1

0. 85 0.9 0.70 0.75 0.80 0.85 0.90 0.95 1.00 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Lamb:ewe ratio (X)

196

Figure 6.3 Contour plot of transient population growth rates (λ) from adult female argali

(Ovis ammon) survival and pre-birth pulse lamb:ewe ratios. We assume that long-term

argali survival is maximized at our study site (Ikh Nart Nature Reserve) and set mean

adult female survival at INNR ( = 0.844) as a ceiling that other locations can attain but

not surpass. Consequently, we can broadly infer population growth rate from any argali

population in Central Asia based on pre-birth pulse lamb:ewe ratios. Age ratios below X*

= 0.37 indicate a declining population (shaded red); age ratios between 0.37 and 0.55

indicate an approximately stable population (shaded gray); and age ratios above 0.55 indicate an increasing population (shaded green).

1.3

1.2 1 .2  =1 1. ^ 15 S

1. 1 05 Adult female survival (S)

1

0. 85 0.9

0.70 0.75 0.80 0.85 0.90 0.95 1.00 X* 0.00.10.20.30.40.50.60.7 Lamb:ewe ratio (X)

197

Figure 6.4 Age ratios can immediately improve monitoring of Central Asian ungulates in the top row, for which adult female survival estimates have been published (Table 6.1); telemetry data but not survival estimates are available for species in the bottom two rows.

Top row, left to right: moose (Alces alces ©author), saiga (Saiga tatarica ©Rich

Reading), argali (Ovis ammon ©author), Mongolian gazelle (Procapra gutturosa

©BBC), caribou (Rangifer tarandus ©B. Huffman), red deer (Cervus elaphus ©author).

Second row: (Gazella subgutturosa ©Altay Zhatkanbayev), Siberian ibex (Capra sibirica ©author), Himalayan musk deer (Moschus leucogaster ©Mandal

Ranjit), Przewalski’s horse (Equus ferus przewalskii ©author), Przewalski’s gazelle

(Procapra przewalskii ©Yilun Qiao). Bottom row: Asiatic wild ass (Equus hemonius

©Sumeet Moghe), takin (Budorcas taxicolor ©Chuck Dresner),

(Camelus ferus ©John Hare), and chiru (Pantholops hodgsonii).

198