Large-bodied Species Research Articles

Warmer temperature decreases the maximum length of six species of marine fishes, crustacean, and squid in New Zealand

As global oceans continue to warm and deoxygenate, it is expected that marine ectotherms will reduce in body size resulting from the interactive effects of temperature and dissolved oxygen availability. A temperature-size response describes how wild populations of ectothermic species grow faster and reach a smaller size within warmer temperatures. While temperature-size responses are well observed in marine ectotherms, the mechanisms underpinning such a reduction in body size remain debated. Here, we analyse the relative influence of temperature, dissolved oxygen concentration, and geographic location (which encompasses multiple latent variables), on the maximum body length of four fish, one crustacean, and one squid species, which inhabit shallow to deep sea (1000 m) New Zealand waters across a temperature gradient of 1.5 to 18 °C. We found that all study species displayed a temperature-size response, with the strongest response exhibited by the largest species, hoki (Macruronus novaezelandiae). We also found that temperature was more important than dissolved oxygen concentration in determining maximum body length, as dissolved oxygen levels were at or near saturation in the study area. Our results suggest that larger-bodied species may experience the strongest temperature-size responses, and support expectations from the gill-oxygen limitation theory (GOLT) and the oxygen and capacity limited thermal tolerance (OCLTT) concept that increases in oxygen demand may be size- and temperature-dependent, thus driving a reduction in maximum body length of marine ectotherms with warming.

Miniaturization in Direct-Developing Frogs from Mexico with the Description of Six New Species

The Craugastor mexicanus series (Anura: Craugastoridae) includes six species of direct-developing frogs that occur in Mexico and Guatemala. Notably, two of these species have small adult body sizes (<18 mm snout to vent length) and several have intraspecific polymorphism in color pattern. Using a geographic sampling focused on eastern Mexico (the location of most type localities), we conducted a molecular phylogenetic analysis of two mitochondrial (12S, 16S) and two nuclear (RAG1, TYR) gene fragments. This analysis revealed two widespread species, C. mexicanus and C. pygmaeus, along with evidence of multiple undescribed taxa from the states of Oaxaca, Mexico, Guerrero, and Jalisco. Interestingly, the widespread species have stratified geographic distributions with the larger bodied clade restricted to high elevations and the smaller bodied clade to low elevations. We also identify regions of Guerrero and Oaxaca where multiple species co-occur. To reevaluate the quality of characters that have been previously used to diagnose species, we tested for heterochrony and sexual dimorphism using microcomputed tomography and linear measurements. We found evidence for paedomorphosis as the mechanism of miniaturization in small-bodied taxa. Linear measurements confirmed that tympanum and body size are sexually dimorphic traits in both small- and large-bodied species. We used this enhanced understanding of morphological variation in the group to describe six new species. Despite this progress, we suspect that additional species await discovery, particularly in western Mexico and east of the Isthmus of Tehuantepec where our sampling efforts were limited.

A global indicator of utilized wildlife populations: Regional trends and the impact of management

A global indicator of utilized wildlife populations: Regional trends and the impact of management

Stride frequency or length? A phylogenetic approach to understand how animals regulate locomotor speed.

Speed regulation in animals involves stride frequency and stride length. While the relationship between these variables has been well documented, it remains unresolved whether animals primarily modify stride frequency or stride length to increase speed. In this study, we explored the interrelationships between these three variables across a sample of 103 tetrapods and assessed whether speed regulation strategy is influenced by mechanical, allometric, phylogenetic or ecological factors. We observed that crouched terrestrial species tend to regulate speed through stride frequency. Such a strategy is energetically costly, but results in greater locomotor maneuverability and greater stability. In contrast, regulating speed through stride length is closely tied to larger arboreal animals with relatively extended limbs. Such movements reduce substrate oscillations on thin arboreal supports and/or helps to reduce swing phase costs. The slope of speed on frequency is lower in small crouched animals than in large-bodied erect species. As a result, substantially more rapid limb movements are matched with only small speed increases in crouched, small-bodied animals. Furthermore, the slope of speed on stride length was inversely proportional to body mass. As such, small changes in stride length can result in relatively rapid speed increases for small-bodied species. These results are somewhat counterintuitive, in that larger species, which have longer limbs and take longer strides, do not appear to gain as much speed increase out of lengthening their stride. Conversely, smaller species that cycle their limbs rapidly do not gain as much speed out of increasing stride frequency as do larger species.

Annual variation in waterbird clutch initiation date in relation to spring thaw in Arctic Russia.

To test for the degree of species-specific variation in clutch initiation date in relation to spring thaw, we recorded first egg dates in 1433 nests of seven large bodied long-distance migratory waterbird species breeding on Ayopechan Island in the Chaun Delta, Chukotka, in the Russian Arctic during 2002-2020. Pacific Loon Gavia pacifica, Sandhill Crane Grus canadensis and Glaucous Gull Larus hyperboreus all adjusted timing of clutch initiation completely to annual variation in first frost-free dates. First egg dates of Spectacled Eider Somateria fischeri also significantly advanced in warmer springs, but the rate of change was significantly less than unity, implying a reduced capacity to accommodate change in vernal thaw that may not be able to keep up with greater change in the future. Long-tailed Duck Clangula hyemalis and Vega Gull Larus vegae showed a tendency for earlier first egg dates in years with earlier first frost-free date, but for both species, the relationship failed to reach statistical significance. Bewick's Swan Cygnus columbianus showed almost no change in mean first egg date across the observed variation in first frost-free dates. Based on these data, we suggest that while all seven species showed signs of plasticity in their timing of onset of breeding, Pacific Loon, Sandhill Crane and Glaucous Gull showed greater adaptability to adjust the timing of their breeding season to recent variation in spring thaw than the other four species studied here over this period.

A skeleton from the Middle Jurassic of Scotland illuminates an earlier origin of large pterosaurs

Pterosaurs were the first vertebrates to evolve flight1,2 and include the largest flying animals in Earth history.3,4 While some of the last-surviving species were the size of airplanes, pterosaurs were long thought to be restricted to small body sizes (wingspans ca. <1.8-1.6 m) from their Triassic origins through the Jurassic, before increasing in size when derived long-skulled and short-tailed pterodactyloids lived alongside a diversity of birds in the Cretaceous.5 We report a new spectacularly preserved three-dimensional skeleton from the Middle Jurassic of Scotland, which we assign to a new genus and species: Dearc sgiathanach gen. et sp. nov. Its wingspan is estimated at >2.5 m, and bone histology shows it was a juvenile-subadult still actively growing when it died, making it the largest known Jurassic pterosaur represented by a well-preserved skeleton. A review of fragmentary specimens from the Middle Jurassic of England demonstrates that a diversity of pterosaurs was capable of reaching larger sizes at this time but have hitherto been concealed by a poor fossil record. Phylogenetic analysis places D.sgiathanach in a clade of basal long-tailed non-monofenestratan pterosaurs, in a subclade of larger-bodied species (Angustinaripterini) with elongate skulls convergent in some aspects with pterodactyloids.6 Far from a static prologue to the Cretaceous, the Middle Jurassic was a key interval in pterosaur evolution, in which some non-pterodactyloids diversified and experimented with larger sizes, concurrent with or perhaps earlier than the origin of birds. VIDEO ABSTRACT.

Taming the temperature: Sagebrush songbirds modulate microclimate via nest-site selection

Abstract Understanding species’ responses to temperature via behavior, and the factors affecting the extent of behavioral responses, is a critical and timely endeavor given the rapid pace at which the climate is changing. The young of altricial songbirds are particularly sensitive to temperature, and parents may modulate temperatures at nests via selection of nest sites, albeit to a largely unknown extent. We examined whether sagebrush-obligate songbirds, that reproduce within an open ecosystem with wide temperature fluctuations and span a range of body sizes, selected their nest sites on the basis of temperature. We further investigated whether nest predation risk and ambient conditions modulated temperature-based choices. We placed temperature loggers at nest sites and in unused but available nest niches and nest shrubs along a known predation-risk gradient and used nearby weather stations to determine ambient temperatures. The two smaller-bodied birds, Brewer’s Sparrow (Spizella breweri) and Sagebrush Sparrow (Artemisiospiza nevadensis), selected nest shrubs and niches that were warmer and less variable relative to unused sites whereas the larger bodied species, Sage Thrashers (Oreoscoptes montanus), did not. Brewer’s Sparrows and Sage Thrashers dampened selection for warmer nest sites when temperatures experienced during the nest-site prospecting period were warmer. None of the three species altered nest-site selection with respect to temperature in response to ambient temperature variability or our index of nest predation risk. The microhabitat characteristics that most influenced temperatures at nests varied across species. Our results suggest that songbirds can modulate temperatures at nests to some extent, and such responses can vary depending on the conditions experienced prior to nest initiation. Responses also varied across species, likely reflecting different physiological tolerances. The extent to which breeding birds will be able to continue to proximately influence temperature via nest-site choices likely will depend on the extent and rate of future climatic shifts.

The Reproductive Success of Triturus ivanbureschi × T. macedonicus F1 Hybrid Females (Amphibia: Salamandridae).

Simple SummaryTwo moderately related large-bodied newt species endemic to the Balkan Peninsula, the Balkan crested newt (Triturus ivanbureschi) and the Macedonian crested newt (T. macedonicus), coexist and hybridize in central Serbia. Many generations of mutual hybrid crossings and backcrossings with parental species shaped the genetic composition of hybrid populations. Natural populations have admixed nuclear DNA (nuDNA) of parental species and T. ivanbureschi mitochondrial DNA (mtDNA), which is usually maternally inherited. The mechanisms that direct gene flow and shape the first generations of hybrids could explain the formation of hybrid zones and their maintenance in nature. We followed and compared life history traits related to reproduction of the first generation of reciprocal hybrids obtained by experimental crossing. Our results suggested that possible incompatibilities between mitochondrial and nuclear genomes, which could lead to the exclusion of T. macedonicus mtDNA in natural populations, most likely act at later stages of development or subsequent hybrid generations. Results from this study add to the growing knowledge of Triturus hybrid biology and ecology, which is the baseline for conservation programs necessary to protect these highly endangered amphibians.Two large-bodied newt species, Triturus ivanbureschi and T. macedonicus, hybridize in nature across the Balkan Peninsula. Consequences of hybridization upon secondary contact of two species include species displacement and asymmetrical introgression of T. ivanbureschi mtDNA. We set an experimental reciprocal cross of parental species and obtained two genotypes of F1 hybrids (with T. ivanbureschi or T. macedonicus mtDNA). When hybrids attained sexual maturity, they were engaged in mutual crossings and backcrossing with parental species. We followed reproductive traits over two successive years. Our main aim was to explore the reproductive success of F1 females carrying different parental mtDNA. Additionally, we tested for differences in reproductive success within female genotypes depending on the crossing with various male genotypes (hybrids or parental species). Both female genotypes had similar oviposition periods, number of laid eggs and hatched larvae but different body and egg sizes. Overall reproductive success (percentage of egg-laying females and viability of embryos) was similar for both genotypes. The type of crossing led to some differences in reproductive success within female genotypes. The obtained results suggest that processes that led to exclusion of T. macedonicus mtDNA in natural populations may be related to the survival at postembryonic stages of F2 generation or reproductive barriers that emerged in subsequent hybrid generations.

Spermatogonia From Cryopreserved Testes of Critically Endangered Chinese Sturgeon Efficiently Colonized and Preferentially Proliferated in the Recipient Gonads of Yangtze Sturgeon.

The critically endangered Chinese sturgeon, Acipenser sinensis, presents late sexual maturity and has a large body size. Germ cell transplantation is a powerful technique for the production of gametes from large-bodied species in closely related recipients with a smaller body size and shorter generation time. To accelerate reproduction of Chinese sturgeon, donor spermatogonia collected from the cryopreserved testes of 3-year-old Chinese sturgeon were intraperitoneally transplanted into 7-8 days post-hatch larvae of Yangtze sturgeon (Acipenser dabryanus) with shorter generation interval. At 2 months post-transplantation (mpt), donor spermatogonia had colonized in the 81.25% of recipient gonads, with average numbers about two times those of endogenous primordial germ cells. Within the next 2 months, the rate of endogenous germ cell division in females (2-3 times) was faster than that in males (once), whereas colonized donor-derived spermatogonia divided about 2-3 times and twice in recipient females and males, respectively. Furthermore, the expression of germ cell-related genes, dazl, dead end, and vasa, in transplanted fish was higher than that in non-transplanted fish, suggesting the incorporation and proliferation donor spermatogonia in recipient. At 18 mpt, donor-derived spermatogonia survived in the 75.00% of recipient gonads. These results showed that the somatic microenvironment of Yangtze sturgeon gonad can support the long-term colonization, proliferation, and survival of xenogeneic germ cells. Thus, this study suggested that small-bodied Yangtze sturgeon is promising recipient as surrogate for Chinese sturgeon gamete production.

Alien fish ascendancy and native fish extinction: ecological history and observations on the Lower Goodradigbee River, Australia

Context The Murray–Darling Basin – Australia’s largest river system – is heavily dominated by alien fish. Native fish species have suffered numerous localised extinctions and ∼47% are listed on federal and/or state threatened species lists. Aims This paper explores the hypothesis that alien fish and alien fish stockings can be the primary cause of decline and localised extinction of large-bodied native fish species, as opposed to habitat degradation and river regulation. The Lower Goodradigbee River, which is unregulated, in excellent instream health over the great majority of its course, and replete with high quality habitat, is utilised as a case study. Methods I investigated the hypothesis by synthesising historical records with contemporary scientific research and recent field observations. The role of alien fish species, particularly alien trout species (Oncorhynchus mykiss and Salmo trutta) and constant stockings of them, were closely examined. Results Data support the hypothesis that domination by alien trout species and their continual stocking have lead to historical declines and localised extinctions of large-bodied native fish species. Continued alien trout stockings, along with more recent invasions of alien carp (Cyprinus carpio) and alien redfin perch (Perca fluviatilis), are inhibiting native fish recovery. A suspected field sighting of the alien fish pathogen atypical Aeromonas salmonicida is reported, and the status of the declining native crayfish Murray cray (Euastacus armatus), and potential alien fish impacts upon them, are examined. Conclusions The impacts of alien fish and alien fish stocking in Australia require major re-evaluation and dedicated research. Implications It is strongly recommended that stocking of alien trout into the Lower Goodradigbee River for angling cease in order to conserve surviving native fish and Murray cray populations. Conservation stockings to effect a Murray cod (Maccullochella peelii) recovery in the Lower Goodradigbee River are warranted.

Community structures of mid-sized to large-bodied mammals in tropical lowland and lower montane forests in Gunung Pueh National Park, Western Sarawak, Borneo

Habitat types are closely associated with altitude gradients in tropical rainforests and play an essential role in species assemblages where terrain heterogeneity is often used to understand effects of climate change on species distribution. The response of larger mammals to habitat variation along altitudes is largely unexplored in Borneo. This study has utilised camera traps to better understand the community structure of larger mammals in Gunung Pueh National Park. Gunung Pueh National Park (1550 m a.s.l.) contains two major habitat types, which include lowland forests (&lt; 1100 m a.s.l.) and the lower montane (&gt; 1100 m a.s.l.) forests. The spatio-temporal niches of mid-sized to large-bodied mammal species across these altitude gradients and habitats were assessed. Cameras located at 23 locations, along varying altitude gradients, resulted in 3109 trap nights. Using these cameras, the collected recordings have revealed a total of 22 mid-sized to large-bodied mammals, including 19 species recorded in lowland forest areas, and 18 species in the lower montane forest areas; 15 species were found in both habitats. Four species were exclusively detected in the lowland forest, namely Rusa unicolor, Viverra tangalunga, Presbytis chrysomelas, and Hystrix brachyura. Three species were detected only in the lower montane forest, namely Herpestes semitorquatus, Mustela nudipes, and Hemigalus hosei. In the lowland forest, Macaca nemestrina was recorded with the highest naïve occupancy (naïve ψ = 1.00), while Hemigalus derbyanus had the highest naïve occupancy (naïve ψ = 0.93) in the lower montane forest. The temporal diel activity patterns of selected species in the two habitats have shown relatively close similarities, with overlapping patterns ranging between 67–90%. The further conservation of a large area, which encompasses mountainous ranges, is recommended to facilitate the conservation efficacy of such Protected Areas and for supporting diverse, mid-sized to large-bodied mammals in Borneo.

Managing yards for mammals: Mammal species richness peaks in the suburbs

Increased urbanization drives habitat loss, yet residential land-use represents significant habitat potential for mammals and could provide connectivity between patches of green spaces. Diverse mammal communities exist across urban gradients, but it is unclear how mammal community composition varies within residential lands. We conducted a camera trapping study in 36 residential yards across an urban gradient to assess the relative contributions of the degree of urbanization in the land-use context versus parcel habitat features, such as vegetation structure, on mammal community diversity and composition. We hypothesized that land-use context would more strongly influence mammal community metrics than parcel features, and that there would be species-specific differences in response. We detected 14 non-domesticated mammal species and found that species richness peaked in the suburbs and tapered off at the rural and urban ends of the gradient in accordance with patterns seen in other taxonomic groups, yet rarely quantified in mammals. Large-bodied interior forest species were associated with rural sites, urban-dwelling species were associated with urban sites, and suburban sites had an overlap of species types. Although composition of mammal species in residential yards appears to be strongly related to land-use context, which is often outside of residents’ control, management of parcel habitat features such as retention of large mature trees may facilitate connectivity between patches of habitat across urbanizing landscapes. Informed residential yard management remains an important tool for urban wildlife management in an era of global change.

Intrinsic and extrinsic motivations governing prey choice by hunters in a post-war African forest-savannah macromosaic.

Overhunting typically increases during and after armed conflicts, and may lead to regional-scale defaunation. The mitigation of hunting impacts is complex because, among other reasons, several intrinsic and extrinsic motivations underpin the elevated deployment of hunting practices. Here we present the first study focusing on these motivations in a post-war zone. Following persistently heavy hunting pressure during the 27-year Angolan civil war, the offtake of small to medium-bodied species has increased recently as a result of large mammal depletion. However, prey choice associated with different motivations varied in terms of species trophic level and body size. While most residents hunted large-bodied species to maximize revenues from wildlife trade, many low-trophic level smaller species were harvested to meet local subsistence demands because they were more palatable and could be captured using artisanal traps near hunters' households. Mainly low-trophic level species were killed in retaliation for crop-raiding or livestock depredation. Considering all game species sampled in this study, 96% were captured to attend two or more motivations. In addition, hunting associated with different motivations was partitioned in terms of age and gender, with prey acquisition for the wildlife trade primarily carried out by adult men, while hunting to meet local subsistence needs and inhibit human-wildlife conflicts were carried out by adult men and women, children and even the elderly. In natural savannah areas lacking fish as a source of protein, a higher number of species was selected to supply both the meat trade and subsistence, while more species in forest areas were targeted for trade in animal body parts and conflict retaliation. Finally, local commerce in bushmeat and other body parts accrued higher domestic revenues compared to any alternative sources of direct and indirect income. However, these financial benefits were at best modest, largely unsustainable in terms of prey population collapses, and generated high long-term costs for the local to regional scale economy and native biodiversity.

Levantine overkill: 1.5 million years of hunting down the body size distribution

Multiple large-bodied species went extinct during the Pleistocene. Changing climates and/or human hunting are the main hypotheses used to explain these extinctions. We studied the causes of Pleistocene extinctions in the Southern Levant, and their subsequent effect on local hominin food spectra, by examining faunal remains in archaeological sites across the last 1.5 million years. We examined whether climate and climate changes, and/or human cultures, are associated with these declines. We recorded animal abundances published in the literature from 133 stratigraphic layers, across 58 Pleistocene and Early Holocene archaeological sites, in the Southern Levant. We used linear regressions and mixed models to assess the weighted mean mass of faunal assemblages through time and whether it was associated with temperature, paleorainfall, or paleoenvironment (C3 vs. C4 vegetation). We found that weighted mean body mass declined log-linearly through time. Mean hunted animal masses 10,500 years ago, were only 1.7% of those 1.5 million years ago. Neither body size at any period, nor size change from one layer to the next, were related to global temperature or to temperature changes. Throughout the Pleistocene, new human lineages hunted significantly smaller prey than the preceding ones. This suggests that humans extirpated megafauna throughout the Pleistocene, and when the largest species were depleted the next-largest were targeted. Technological advancements likely enabled subsequent human lineages to effectively hunt smaller prey replacing larger species that were hunted to extinction or until they became exceedingly rare.

Species richness and identity both determine the biomass of global reef fish communities

Changing biodiversity alters ecosystem functioning in nature, but the degree to which this relationship depends on the taxonomic identities rather than the number of species remains untested at broad scales. Here, we partition the effects of declining species richness and changing community composition on fish community biomass across >3000 coral and rocky reef sites globally. We find that high biodiversity is 5.7x more important in maximizing biomass than the remaining influence of other ecological and environmental factors. Differences in fish community biomass across space are equally driven by both reductions in the total number of species and the disproportionate loss of larger-than-average species, which is exacerbated at sites impacted by humans. Our results confirm that sustaining biomass and associated ecosystem functions requires protecting diversity, most importantly of multiple large-bodied species in areas subject to strong human influences.

Profiling insular vertebrates prone to biological invasions: What makes them vulnerable?

Invasive alien species (IAS) are a major threat to insular vertebrates, although the ecological characteristics that make insular communities vulnerable to IAS are poorly understood. After describing the ecological strategies of 6015 insular amphibians, birds, lizards, and mammals, we assessed the functional and ecological features of vertebrates exposed to IAS. We found that at least 50% of insular amphibian functional richness was hosted by IAS-threatened amphibians and up to 29% for birds. Moreover, all IAS-threatened groups except birds harbored a higher functional richness than species groups threatened by other threats. Disentangling the ecological strategies threatened by IAS, compared to those associated with other threats, we showed that birds, lizards, and mammals were more likely to be terrestrial foragers and amphibians to have larval development. By contrast, large-bodied species and habitat specialists were universally threatened. By considering the functional aspect of threatened insular diversity, our work improves our understanding of global IAS impacts. This new dimension proves essential for undertaking relevant and effective conservation actions.

Using interview surveys and multispecies occupancy models to inform vertebrate conservation.

Species distribution data are an essential biodiversity variable requiring robust monitoring to inform wildlife conservation. Yet, such data remain inherently sparse because of the logistical challenges of monitoring biodiversity across broad geographic extents. Surveys of people knowledgeable about the occurrence of wildlife provide an opportunity to evaluate species distributions and the ecology of wildlife communities across large spatial scales. We analyzed detection histories of 30 vertebrate species across the Western Ghats biodiversity hotspot in India, obtained from a large-scale interview survey of 2318 people who live and work in the forests of this region. We developed a multispecies occupancy model that simultaneously corrected for false-negative (non-detection) and false-positive (misidentification) errors that interview surveys can be prone to. Using this model, we integrated data across species in composite analyses of the responses of functional species groups (based on disturbance tolerance, diet, and body mass traits) to spatial variation in environmental variables, protection, and anthropogenic pressures. We observed a positive association between forest cover and the occurrence of species with low tolerance of human disturbance. Protected areas were associated with higher occurrence for species across different functional groups compared with unprotected lands. We also observed the occurrence of species with low disturbance tolerance, herbivores, and large-bodied species was negatively associated with developmental pressures, such as human settlements, energy production and mining, and demographic pressures, such as biological resource extraction. For the conservation of threatened vertebrates, our work underscores the importance of maintaining forest cover and reducing deforestation within and outside protected areas, respectively. In addition, mitigating a suite of pervasive human pressures is also crucial for wildlife conservation in one of the world's most densely populated biodiversity hotspots.

Dietary flexibility of Wood Storks in response to human-induced rapid environmental change

Human-induced rapid environmental change (HIREC) has altered landscape processes and negatively impacted many species globally. Some of the most dramatic changes have been in wetlands where flows have been disrupted, and new wetlands have been created to retain runoff. In response to disrupted natural wetland conditions, Wood Stork (Mycteria americana) populations in South Florida have significantly declined over the past several decades. Despite the well-documented sensitivity of Wood Storks to natural wetland conditions, Wood Storks are often observed foraging in roadside created wetlands; however, the availability of prey in created wetlands is currently unknown. We sampled natural and created wetlands to determine aquatic fauna available for foraging Wood Storks. To determine prey use, we collected food boluses from Wood Storks in both natural wetland and urban landscapes. Historical studies found nonnative fish were absent in Wood Stork diet prior to the dominance of created wetlands in the landscape; however, we found nonnative fish frequently in both created wetlands and boluses. Furthermore, urban nesting Wood Storks consumed large-bodied prey species that were more characteristic of created wetlands whereas Wood Storks nesting in natural wetlands consumed large-bodied prey more characteristic of natural wetlands. Overall, Wood Storks consumed prey that were more similar to the fish community in created wetlands than those in natural wetlands. These dietary patterns suggest that Wood Storks have behavioral plasticity in both foraging habitat and prey use to cope with HIREC. Conservation efforts for species existing in both natural and urban habitats should consider the importance of novel prey and foraging habitats, as they may assist in sustaining populations in a rapidly changing world.

Environmental drivers of sympatric mammalian species compositional turnover in giant panda nature reserves: Implications for conservation

The charismatic giant panda (Ailuropoda melanoleuca) is an iconic species of wildlife conservation worldwide. As the most effective measure to protect giant pandas and their habitats, China has established 67 giant panda nature reserves (GPNR) during the last five decades, which also bring benefits to many sympatric medium- and large-bodied mammals (MLM). To better inform the planning of the GPNR network with the view of preserving regional MLM diversity, we investigated the zeta diversity (a novel index to measure species compositional turnover considering the contributions of both rare and common species) patterns (i.e. zeta decline and retention rate curve) of MLMs across 40 GPNRs. The effects of species’ body mass and conservation status on the zeta diversity patterns were tested. Further, we applied the multi-site generalized dissimilarity modelling (MS-GDM) framework to explore the impacts of environmental and geographic distances on MLM turnover. The results indicated that there are a core set of 17 MLM species sympatric with the giant panda in the GPNRs. Species’ body mass can affect the patterns of zeta decline and retention rate curves, and the number of large-bodied species shared by multiple GPNRs is higher than that of medium-bodied species across zeta orders. The MS-GDM revealed the important roles of difference in habitat heterogeneity and spatial distance between GPNRs in driving MLM turnover. Consequently, we advocate maintaining and increasing the diversity of (natural) habitats in GPNRs to protect giant panda's sympatric MLM diversity. The government should consider optimizing the GPNR network (e.g. incorporating multiple small GPNRs into one single large reserve) to capture the most turnover of MLMs, and the newly-established Giant Panda National Park is relevant to fulfilling this long-term goal.

Human disturbance and shifts in vertebratecommunity compositionin a biodiversity hotspot.

Understanding how human modification of the landscape shapes vertebrate community composition is vital to understanding the current status and future trajectory of wildlife. Using a participatory approach, we deployed the largest camera-trap network in Mesoamerica to date to investigate how anthropogenic disturbance shapes the occupancy and co-occurrence of terrestrial vertebrate species in a tropical biodiversity hotspot: the Osa Peninsula, Costa Rica. We estimated species richness in different categories of land protection with rarefaction analysis and estimated the expected occupancy with a joint species distribution model that included covariates for anthropogenic disturbance, land protection, habitat quality, and habitat availability. Areas with the most stringent land-use protections (e.g., Corcovado National Park, 24 species [95% CI 23-25]) harbored significantly more species than unprotected areas (20 species [19.7-20.3]), mainly due to a reduced presence of large-bodied species of conservation concern in unprotected areas (e.g., jaguar Panthera onca and white-lipped peccary Tayassu pecari). Small-bodied generalist species, such as opossums (Didelphidae) and armadillos (Dasypus novemcinctus), in contrast, were more common at disturbed sites, resulting in a significant difference in vertebrate community composition between sites with low and high disturbance. Co-occurrence of species was also mainly associated with response to disturbance. Similar responses to disturbance create two groups of species, those whose site-level occupancy usually increased as anthropogenic disturbance increased and those whose estimated occupancy decreased. The absence of large-bodied species entails an important loss of ecological function in disturbed areas and can hinder forest development and maintenance. Efforts to protect and restore forested landscapes are likely having a positive effect on the abundance of some threatened species. These efforts, however, must be sustained and expanded to increase connectivity and ensure the long-term viability of the wildlife community.