Conservation outside Protected Areas and the Effect of Human‐Dominated Landscapes on Stress Hormones in Savannah Elephants

Biodiversity conservation strategies are increasingly focused on regions outside national protected areas, where animals face numerous anthropogenic threats and must coexist with human settlements, livestock, and agriculture. The effects of these potential threats are not always clear, but they could have profound implications for population viability. We used savannah elephants (Loxodonta africana) as a case study to assess the physiological stress associated with living in a human‐livestock‐dominated landscape. We collected samples over two 3‐month periods in 2007 and 2008. We used fecal DNA to identify 96 individual elephants in a community conservation area (CCA) and measured fecal glucocorticoid metabolite (FGM) concentrations as a proxy for stress. The CCA is community Maasai land managed for livestock and wildlife. We compared the FGM concentrations from the CCA to FGM concentrations of 40 elephants in Amboseli National Park and 32 elephants in the Maasai Mara National Reserve, where human settlements and intense livestock grazing were absent. In the CCA, we found no significant individual differences in FGM concentrations among the elephants in 2007 (p = 0.312) or 2008 (p = 0.412) and no difference between years (p = 0.616). The elephants in the CCA had similar FGM concentrations to the Maasai Mara population, but Amboseli elephants had significantly lower FGM concentrations than those in either Maasai Mara or the CCA (Tukey pairwise test, p < 0.001), due primarily to females excreting significantly lower FGM relative to males (p = 0.025). In the CCA, there was no relation among female group size, average pairwise group relatedness, and average group FGM concentration. We found no clear evidence of chronic stress in elephants living on CCA communal land, which is encouraging for conservation strategies promoting the protection of animals living outside protected areas. Conservación Fuera de Áreas Protegidas y el Efecto de Paisajes Dominados por Humanos sobre Hormonas del Estrés en Elefantes Africanos     

The consequences of poaching and anthropogenic change for forest elephants

Poaching has devastated forest elephant populations (Loxodonta cyclotis), and their habitat is dramatically changing. The long‐term effects of poaching and other anthropogenic threats have been well studied in savannah elephants (Loxodonta africana), but the impacts of these changes for Central Africa's forest elephants have not been discussed. We examined potential repercussions of these threats and the related consequences for forest elephants in Central Africa by summarizing the lessons learned from savannah elephants and small forest elephant populations in West Africa. Forest elephant social organization is less known than the social organization of savannah elephants, but the close evolutionary history of these species suggests that they will respond to anthropogenic threats in broadly similar ways. The loss of older, experienced individuals in an elephant population disrupts ecological, social, and population parameters. Severe reduction of elephant abundance within Central Africa's forests can alter plant communities and ecosystem functions. Poaching, habitat alterations, and human population increase are probably compressing forest elephants into protected areas and increasing human–elephant conflict, which negatively affects their conservation. We encourage conservationists to look beyond documenting forest elephant population decline and address the causes of these declines when developing conversation strategies. We suggest assessing the effectiveness of the existing protected‐area networks for landscape connectivity in light of current industrial and infrastructure development. Longitudinal assessments of the effects of landscape changes on forest elephant sociality and behavior are also needed. Finally, lessons learned from West African elephant population loss and habitat fragmentation should be used to inform strategies for land‐use planning and managing human–elephant interactions.     

Effects of Economic Downturns on Mortality of Wild African Elephants

Abstract: Declines in economic activity and associated changes in human livelihood strategies can increase threats of species overexploitation. This is exemplified by the effects of economic crises, which often drive intensification of subsistence poaching and greater reliance on natural resources. Whereas development theory links natural resource use to social‐economic conditions, few empirical studies of the effect of economic downturns on wild animal species have been conducted. I assessed the relations between African elephant (Loxodonta africana) mortality and human‐caused wounds in Samburu, Kenya and (1) livestock and maize prices (measures of local economic conditions), (2) change in national and regional gross domestic product (GDP) (measures of macroeconomic conditions), and (3) the normalized difference vegetation index (NDVI) (a correlate of primary productivity). In addition, I analyzed household survey data to determine the attitudes of local people toward protected areas and wild animals in the area. When cattle prices in the pastoralist study region were low, human‐caused wounds to and adult mortality of elephants increased. The NDVI was negatively correlated with juvenile mortality, but not correlated with adult mortality. Changes in Kenyan and East Asian (primary market for ivory) GDP did not explain significant variation in mortality. Increased human wounding of elephants and elephant mortality during periods of low livestock prices (local economic downturns) likely reflect an economically driven increase in ivory poaching. Local but not macroeconomic indices explained significant variation in mortality, likely due to the dominance of the subsistence economy in the study area and its political and economic isolation. My results suggest economic metrics can serve as effective indicators of changes in human use of and resulting effects on natural resources. Such information can help focus management approaches (e.g., antipoaching effort or proffering of alternative occupational opportunities) that address variation in local activities that threaten plant and animal populations.     

Tracking Chinese newspaper coverage of elephant ivory through topic modeling

Mass media worldwide has contributed to increasing awareness of the illegal wildlife trade and its significant impact on wildlife conservation. We used mass media coverage as a proxy for macro-level public opinion to analyze the media framing of elephant ivory in 6394 Chinese newspaper articles published from 2000 to 2021 and thus determine the effects of wildlife policies on public opinion. We focused on 2 events: the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) approval of China as a trading partner in the purchase and import of ivory stockpiles from Africa in July 2008 and the Chinese government's announcement of a domestic ivory ban in December 2016. Using latent Dirichlet allocation topic modeling, we identified 8 topics about elephant ivory and grouped them into 3 frames: ivory arts and culture, ivory crimes, and elephant conservation. Over the last 2 decades, topics related to ivory crimes remained the most prevalent in news articles. Topics about ivory arts and culture showed a significant shift in media salience before and after the 2 events (from 0.44 to 0.19 and from 0.08 to 0.15, respectively, p < 0.05), whereas the other 2 frames did not change significantly. Contrary to popular belief, our results indicated that Chinese macro-level public opinion on ivory had become more negative following the CITES approval of ivory importation and less negative after the ivory ban announcement, at least for certain periods. The relationship between mass media, public opinion, and wildlife trade policies is complex and requires further examination of the sociopolitical dynamics that influence media narratives. Our results showed the value of topic modeling in monitoring and assessing media representations of wildlife issues in the era of big data. Conservationists should remain vigilant of mass media coverage and collaborate with media practitioners to produce comprehensive narratives on wildlife issues if resources permit.     

Using Genetic Profiles of African Forest Elephants to Infer Population Structure,Movements, and Habitat Use in a Conservation and Development Landscape in Gabon

Conservation of wide‐ranging species, such as the African forest elephant (Loxodonta cyclotis), depends on fully protected areas and multiple‐use areas (MUA) that provide habitat connectivity. In the Gamba Complex of Protected Areas in Gabon, which includes 2 national parks separated by a MUA containing energy and forestry concessions, we studied forest elephants to evaluate the importance of the MUA to wide‐ranging species. We extracted DNA from elephant dung samples and used genetic information to identify over 500 individuals in the MUA and the parks. We then examined patterns of nuclear microsatellites and mitochondrial control‐region sequences to infer population structure, movement patterns, and habitat use by age and sex. Population structure was weak but significant, and differentiation was more pronounced during the wet season. Within the MUA, males were more strongly associated with open habitats, such as wetlands and savannas, than females during the dry season. Many of the movements detected within and between seasons involved the wetlands and bordering lagoons. Our results suggest that the MUA provides year‐round habitat for some elephants and additional habitat for others whose primary range is in the parks. With the continuing loss of roadless wilderness areas in Central Africa, well‐managed MUAs will likely be important to the conservation of wide‐ranging species. Utilización de Perfiles Genéticos de Elefantes Africanos para Inferir su Estructura Poblacional, Movimientos y Uso del Hábitat en un Paisaje con Conservación y Desarrollo en Gabón Resumenfgs     

Legal ivory trade in a corrupt world and its impact on African elephant populations

Illegal hunting of African elephants (Loxodonta africana) for ivory is causing rapid declines in their populations. Since 2007, illegal ivory trade has more than doubled. African elephants are facing the most serious conservation crisis since 1989, when international trade was banned. One solution proposed is establishment of a controlled legal trade in ivory. High prices for ivory mean that the incentives to obtain large quantities are high, but the quantity of tusks available for trade are biologically constrained. Within that context, effective management of a legal ivory trade would require robust systems to be in place to ensure that ivory from illegally killed elephants cannot be laundered into a legal market. At present, that is not feasible due to corruption among government officials charged with implementing wildlife‐related legislation. With organized criminal enterprises involved along the whole commodity chain, corruption enables the laundering of illegal ivory into legal or potentially legal markets. Poachers and traffickers can rapidly pay their way out of trouble, so the financial incentives to break the law heavily outweigh those of abiding by it. Maintaining reliable permitting systems and leak‐proof chains of custody in this context is challenging, and effective management breaks down. Once illegal ivory has entered the legal trade, it is difficult or impossible for enforcement officers to know what is legal and illegal. Addressing corruption throughout a trade network that permeates countries across the globe will take decades, if it can ever be achieved. That will be too late for wild African elephants at current rates of loss. If we are to conserve remaining wild populations, we must close all markets because, under current levels of corruption, they cannot be controlled in a way that does not provide opportunities for illegal ivory being laundered into legal markets. Comercio Legal de Marfil en un Mundo Corrupto y su Imapacto sobre Poblaciones de Elefantes     

Use of Acoustic Tools to Reveal Otherwise Cryptic Responses of Forest Elephants to Oil Exploration

Abstract: Most evaluations of the effects of human activities on wild animals have focused on estimating changes in abundance and distribution of threatened species; however, ecosystem disturbances also affect aspects of animal behavior such as short‐term movement, activity budgets, and reproduction. It may take a long time for changes in behavior to manifest as changes in abundance or distribution. Therefore, it is important to have methods with which to detect short‐term behavioral responses to human activity. We used continuous acoustic and seismic monitoring to evaluate the short‐term effects of seismic prospecting for oil on forest elephants (Loxodonta cyclotis) in Gabon, Central Africa. We monitored changes in elephant abundance and activity as a function of the frequency and intensity of acoustic and seismic signals from dynamite detonation and human activity. Elephants did not flee the area being explored; the relative number of elephants increased in a seasonal pattern typical of elsewhere in the ecosystem. In the exploration area, however, they became more nocturnal. Neither the intensity nor the frequency of dynamite blasts affected the frequency of calling or the daily pattern of elephant activity. Nevertheless, the shift of activity to nocturnal hours became more pronounced as human activity neared each monitored area of forest. This change in activity pattern and its likely causes would not have been detected through standard monitoring methods, which are not sensitive to behavioral changes over short time scales (e.g., dung transects, point counts) or cover a limited area (e.g., camera traps). Simultaneous acoustic monitoring of animal communication, human, and environmental sounds allows the documentation of short‐term behavioral changes in response to human disturbance.     

Beehive fences as a multidimensional conflict‐mitigation tool for farmers coexisting with elephants

Increasing habitat fragmentation and human population growth in Africa has resulted in an escalation in human–elephant conflict between small‐scale farmers and free‐ranging African elephants (Loxodonta Africana). In 2012 Kenya Wildlife Service (KWS) implemented the national 10‐year Conservation and Management Strategy for the Elephant in Kenya, which includes an action aimed at testing whether beehive fences can be used to mitigate human–elephant conflict. From 2012 to 2015, we field‐tested the efficacy of beehive fences to protect 10 0.4‐ha farms next to Tsavo East National Park from elephants. We hung a series of beehives every 10 m around the boundary of each farm plot. The hives were linked with strong wire. After an initial pilot test with 2 farms, the remaining 8 of 10 beehive fences also contained 2‐dimensional dummy hives between real beehives to help reduce the cost of the fence. Each trial plot had a neighboring control plot of the same size within the same farm. Of the 131 beehives deployed 88% were occupied at least once during the 3.5‐year trial. Two hundred and fifty‐three elephants, predominantly 20–45 years old entered the community farming area, typically during the crop‐ ripening season. Eighty percent of the elephants that approached the trial farms were kept out of the areas protected by the beehive fences, and elephants that broke a fence were in smaller than average groups. Beehive fences not only kept large groups of elephants from invading the farmland plots but the farmers also benefited socially and financially from the sale of 228 kg of elephant‐friendly honey. As news of the success of the trial spread, a further 12 farmers requested to join the project, bringing the number of beehive fence protected farms to 22 and beehives to 297. This demonstrates positive adoption of beehive fences as a community mitigation tool. Understanding the response of elephants to the beehive fences, the seasonality of crop raiding and fence breaking, and the willingness of the community to engage with the mitigation method will help contribute to future management strategies for this high human–elephant conflict hotspot and other similar areas in Kenya.     

Distribution of a Community of Mammals in Relation to Roads and Other Human Disturbances in Gabon,Central Africa

We present the first community‐level study of the associations of both roads and other human disturbances with the distribution of mammals in Gabon (central Africa). Our study site was in an oil concession within a littoral mosaic landscape. We conducted surveys along 199 line transects and installed camera traps on 99 of these transects to document mammal presence and abundance. We used generalized linear mixed‐effect models to document associations between variables related to the ecosystem (land cover, topography, and hydrology), roads (coating, width of rights of way, condition, type of vehicle used on the road, traffic level, affiliation of users, and general type of road), and other human disturbances (urbanization, agriculture, hunting, logging, gathering, and industrial activities) and the abundance or presence of 17 species or groups of mammals including elephant (Loxodonta cyclotis), buffalo (Syncerus caffer), sitatunga (Tragelaphus spekei), red river hog (Potamochoerus porcus), smaller ungulates, gorilla (Gorilla gorilla), chimpanzee (Pan troglodytes), side‐striped jackal (Canis adustus), carnivores, monkeys, and large rodents. Some types of roads and other human disturbances were negatively associated with the abundance or presence of elephants, buffalos, gorillas, sitatungas, some monkeys, and duikers. The pattern of associations of mammals with roads and other human disturbances was diverse and included positive associations with road presence (red river hog, some monkeys, and duikers), agriculture (sitatunga, small carnivores, and large rodents) and industrial activities (sitatunga, red river hog, red duikers, and side‐striped jackal). Our results suggest that the community of mammals we studied was mostly affected by hunting, agriculture, and urbanization, which are facilitated by road presence. We recommend increased regulation of agriculture, hunting, and road building in the area. Distribución de una Comunidad de Mamíferos en Relación a Carreteras y Otras Perturbaciones Humanas en Gabón, Africa Central     

Ecological consequences of forest elephant declines for Afrotropical forests

Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant‐free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long‐term conservation will require land‐use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging.     

Noninvasive Stress and Reproductive Measures of Social and Ecological Pressures in Free-Ranging African Elephants

Abstract: The African elephant (   Loxodonta africana ) experienced a poaching-related 60% population decline between 1979 and 1988 that was inordinately concentrated on adults. This, coupled with political pressures to delist the elephant, has created a need for noninvasive physiological measures that can quantify the long-term effects of past mortality patterns of this long-lived species. We collected fresh fecal samples from 16 female elephants in three different groups over 23 months at Tarangire National Park, Tanzania, and analyzed them for fecal progesterone and cortisol metabolites. Social and ecological measures were collected concurrently. Fecal progesterone metabolite measures corresponded significantly with stage of gestation, and appear to be able to confirm pregnancy in female elephants from as early as 3 months of gestation. We found that progesterone metabolite concentrations were significantly lower during the dry season than during the wet season after controlling for stage of gestation. Fecal cortisol metabolite concentrations showed the opposite seasonal pattern, being significantly higher in the dry season and inversely correlated with rainfall across seasons. Fecal cortisol metabolite concentrations also increased with group size and were correlated positively with dominance rank in the largest group. Our results suggest that measures of progesterone and cortisol metabolites in feces provide indices of reproductive function and physiological stress that can quantify both natural and human disturbances in African elephants. These measures are ideally suited for monitoring the long-term effects of social disruption from poaching and a variety of other management concerns.     

Mechanistic understanding of human–wildlife conflict through a novel application of dynamic occupancy models

Crop and livestock depredation by wildlife is a primary driver of human–wildlife conflict, a problem that threatens the coexistence of people and wildlife globally. Understanding mechanisms that underlie depredation patterns holds the key to mitigating conflicts across time and space. However, most studies do not consider imperfect detection and reporting of conflicts, which may lead to incorrect inference regarding its spatiotemporal drivers. We applied dynamic occupancy models to elephant crop depredation data from India between 2005 and 2011 to estimate crop depredation occurrence and model its underlying dynamics as a function of spatiotemporal covariates while accounting for imperfect detection of conflicts. The probability of detecting conflicts was consistently <1.0 and was negatively influenced by distance to roads and elevation gradient, averaging 0.08–0.56 across primary periods (distinct agricultural seasons within each year). The probability of crop depredation occurrence ranged from 0.29 (SE 0.09) to 0.96 (SE 0.04). The probability that sites raided by elephants in primary period t would not be raided in primary period t + 1 varied with elevation gradient in different seasons and was influenced negatively by mean rainfall and village density and positively by distance to forests. Negative effects of rainfall variation and distance to forests best explained variation in the probability that sites not raided by elephants in primary period t would be raided in primary period t + 1. With our novel application of occupancy models, we teased apart the spatiotemporal drivers of conflicts from factors that influence how they are observed, thereby allowing more reliable inference on mechanisms underlying observed conflict patterns. We found that factors associated with increased crop accessibility and availability (e.g., distance to forests and rainfall patterns) were key drivers of elephant crop depredation dynamics. Such an understanding is essential for rigorous prediction of future conflicts, a critical requirement for effective conflict management in the context of increasing human–wildlife interactions.     

Evolutionary Distinctiveness,Threat Status,and Ecological Oddity in Primates

Abstract: The EDGE (evolutionarily distinct and globally endangered) conservation program ( http://www.edgeofexistence.org ) uses a composite measure of threat and phylogenetic isolation to rank species for conservation attention. Using primates as a test case, we examined how species that rank highly with this metric represent the collective from which they are drawn. We considered the ecological and morphological traits, including body mass, diet, terrestriality, and home range size, of all 233 species of primates. Overall, EDGE score and the level of deviance from the mean of 20 different ecological, reproductive, and morphological variables were correlated (mean correlation r =0.14, combined p =1.7 × 10^?14). Although primates with a high EDGE score had characteristics that made them seem odd, they did not seem to express more ancestral characteristics than expected. Sets of primate species with high EDGE scores will, therefore, collectively capture a broader than expected range of the biology of the clade. If similar patterns hold in other groups, the EDGE metric may be useful for prioritizing biodiversity for conservation.     

Female choice contributes to offspring fitness in the field cricket,Gryllus bimaculatus (De Geer)

Summary Females of the field cricket, Gryllus bimaculatus, are known to mate non-randomly with respect to male size. The reproductive output of females allowed to choose their mates was compared with that of females allocated mates. Females allowed to choose their mates laid a greater proportion of their available eggs, thereby investing more heavily in reproduction. Female choice did not appear to influence hatching success, suggesting that no short term benefits are derived from non-random mating. However, the offspring of females allowed to choose their mates developed more rapidly and began their own reproductive output before those of females who had been allocated mates. Furthermore, the faster developing offspring of females who chose their mates tended to have a consistantly higher survival rate as well as a lower variance in survival (i.e. less risk of mortality) at adult eclosion. Female choice may therefore contribute to offspring fitness and thus to long term reproductive success. Females allocated large males as mates did not equal those of females allowed to choose their mates, in terms of reproductive output and offspring fitness. This suggests that females may choose their mates with regard to a mixture of characters of which male size is only one.     

Molecular genetic and behavioral analysis of social organization in the Asian elephant (Elephas maximus)

We report on the genetic evaluation and behavioral study of social organization in the Asian elephant (Elephas maximus). Although Asian elephants and African elephants (Loxodonta africana) were previously thought to have similar social organizations, our results demonstrate a substantial difference in the complexity and structure of Asian elephant social groupings from that described for African savanna elephants. Photographic cataloging of individuals, radio telemetry, and behavioral observations in Ruhuna National Park, Sri Lanka, enabled us to assign associated females and young to four groups with overlapping ranges. Genetic sampling of individuals from the four groups in Ruhuna National Park and three other groups in surrounding areas, conducted through PCR amplification and sequencing of mitochondrial DNA from dung, supported the matriarchal nature of female groups and the lack of inter-group transfer of females. Behaviorally and genetically, the identified social groups were best described as ”family groups”. We did not find any evidence for the existence of social groups of higher complexity than family groups. Received: 25 March 2000 / Received in revised form: 28 March 2000 / Accepted: 1 April 2000     

Dominance,kinship and reproductive value in female Barbary macaques (Macaca sylvanus) at Affenberg Salem

Summary In the course of a long-term study on social organization of semi-free-ranging Barbary macaques (Macaca sylvanus) at Affenberg Salem, genealogical and cross-genealogical rank relations of adult and adolescent females in three social groups were studied. Female rank was highly dependent on maternal rank, but the process of rank acquisition was also affected by age/size differences between members of different families. Mother-daughter rank reversal was rare, but all old, postreproductive matriarchs were outranked by their adult daughters. Contrary to findings of other studies on macaques, younger sisters seldom outranked older sisters. There was no genealogy with a strict age-inversed hierarchy among adult sisters as described for rhesus and Japanese macaques. Rank reversals between sisters were more frequent in genealogies with old or dead matriarchs, in large clans, and in dyads with an age difference of more than 1 year, indicating that demographic variables influence intra-genealogical dominance relations. It is suggested that close, long-lasting relationships between sisters and mothers and doughters impede rank reversals. Previous evolutionary models of female dominance relations in primates that explain rank relations among sisters as a function of their reproductive value or as a strategy of the mother to maintain her own status are not supported by the data. The results of this and other studies indicate that rank reversal between sisters is not as universal for Old World monkeys, or even macaques, as frequently proposed.     

Reach and messages of the world's largest ivory burn

Recent increases in ivory poaching have depressed African elephant populations. Successful enforcement has led to ivory stockpiling. Stockpile destruction is becoming increasingly popular, and most destruction has occurred in the last 5 years. Ivory destruction is intended to send a strong message against ivory consumption, both in promoting a taboo on ivory use and catalyzing policy change. However, there has been no effort to establish the distribution and extent of media reporting on ivory destruction events globally. We analyzed media coverage of the largest ivory destruction event in history (Kenya, 30 April 2016) across 11 nation states connected to ivory trade. We used an online‐media crawling tool to search online media outlets and subjected 5 of the largest print newspapers (by circulation) in 5 nations of interest to content analysis. Most online news on the ivory burn came from the United States (81% of 1944 articles), whereas most of the print news articles came from Kenya (61% of 157 articles). Eighty‐six to 97% of all online articles reported the burn as a positive conservation action, whereas 4–50% discussed ivory burning as having a negative impact on elephant conservation. Most articles discussed law enforcement and trade bans as effective for elephant conservation. There was more relative search interest globally in the 2016 Kenyan ivory burn than any other burn in 5 years. Ours is the first attempt to track the reach of media coverage relative to an ivory burn and provides a case study in tracking the effects of a conservation‐marketing event.     

Sex‐Biased Inbreeding Effects on Reproductive Success and Home Range Size of the Critically Endangered Black Rhinoceros

A central premise of conservation biology is that small populations suffer reduced viability through loss of genetic diversity and inbreeding. However, there is little evidence that variation in inbreeding impacts individual reproductive success within remnant populations of threatened taxa, largely due to problems associated with obtaining comprehensive pedigree information to estimate inbreeding. In the critically endangered black rhinoceros, a species that experienced severe demographic reductions, we used model selection to identify factors associated with variation in reproductive success (number of offspring). Factors examined as predictors of reproductive success were age, home range size, number of nearby mates, reserve location, and multilocus heterozygosity (a proxy for inbreeding). Multilocus heterozygosity predicted male reproductive success (p< 0.001, explained deviance >58%) and correlated with male home range size (p < 0.01, r² > 44%). Such effects were not apparent in females, where reproductive success was determined by age (p < 0.01, explained deviance 34%) as females raise calves alone and choose between, rather than compete for, mates. This first report of a 3‐way association between an individual male's heterozygosity, reproductive output, and territory size in a large vertebrate is consistent with an asymmetry in the level of intrasexual competition and highlights the relevance of sex‐biased inbreeding for the management of many conservation‐priority species. Our results contrast with the idea that wild populations of threatened taxa may possess some inherent difference from most nonthreatened populations that necessitates the use of detailed pedigrees to study inbreeding effects. Despite substantial variance in male reproductive success, the increased fitness of more heterozygous males limits the loss of heterozygosity. Understanding how individual differences in genetic diversity mediate the outcome of intrasexual competition will be essential for effective management, particularly in enclosed populations, where individuals have restricted choice about home range location and where the reproductive impact of translocated animals will depend upon the background distribution in individual heterozygosity. Efectos de la Endogamia Sesgada por el Sexo sobre el Éxito Reproductivo y el Rango del Tamaño de Hábitat del Rinoceronte Negro, Especie en Peligro Crítico     

The role of life histories and trophic interactions in population recovery

Factors affecting population recovery from depletion are at the focus of wildlife management. Particularly, it has been debated how life‐history characteristics might affect population recovery ability and productivity. Many exploited fish stocks have shown temporal changes towards earlier maturation and reduced adult body size, potentially owing to evolutionary responses to fishing. Whereas such life‐history changes have been widely documented, their potential role on stock's ability to recover from exploitation often remains ignored by traditional fisheries management. We used a marine ecosystem model parameterized for Southeastern Australian ecosystem to explore how changes towards “faster” life histories might affect population per capita growth rate r. We show that for most species changes towards earlier maturation during fishing have a negative effect (3–40% decrease) on r during the recovery phase. Faster juvenile growth and earlier maturation were beneficial early in life, but smaller adult body sizes reduced the lifetime reproductive output and increased adult natural mortality. However, both at intra‐ and inter‐specific level natural mortality and trophic position of the species were as important in determining r as species longevity and age of maturation, suggesting that r cannot be predicted from life‐history traits alone. Our study highlights that factors affecting population recovery ability and productivity should be explored in a multi‐species context, where both age‐specific fecundity and survival schedules are addressed simultaneously. It also suggests that contemporary life‐history changes in harvested species are unlikely to increase their resilience and recovery ability.     

Effects of Invasive Cordgrass on Presence of Marsh Grassbird in an Area where It Is Not Native

The threatened Marsh Grassbird (Locustella pryeri) first appeared in the salt marsh in east China after the salt marsh was invaded by cordgrass (Spartina alterniflora), a non‐native invasive species. To understand the dependence of non‐native Marsh Grassbird on the non‐native cordgrass, we quantified habitat use, food source, and reproductive success of the Marsh Grassbird at the Chongming Dongtan (CMDT) salt marsh. In the breeding season, we used point counts and radio‐tracking to determine habitat use by Marsh Grassbirds. We analyzed basal food sources of the Marsh Grassbirds by comparing the δ¹³C isotope signatures of feather and fecal samples of birds with those of local plants. We monitored the nests through the breeding season and determined the breeding success of the Marsh Grassbirds at CMDT. Density of Marsh Grassbirds was higher where cordgrass occurred than in areas of native reed (Phragmites australis) monoculture. The breeding territory of the Marsh Grassbird was composed mainly of cordgrass stands, and nests were built exclusively against cordgrass stems. Cordgrass was the major primary producer at the base of the Marsh Grassbird food chain. Breeding success of the Marsh Grassbird at CMDT was similar to breeding success within its native range. Our results suggest non‐native cordgrass provides essential habitat and food for breeding Marsh Grassbirds at CMDT and that the increase in Marsh Grassbird abundance may reflect the rapid spread of cordgrass in the coastal regions of east China. Our study provides an example of how a primary invader (i.e., cordgrass) can alter an ecosystem and thus facilitate colonization by a second non‐native species. Efectos de Spartina alterniflora Invasora Sobre Locustella pryeri en un Área Donde No Es Nativa