Unproductive Habitats Research Articles

Fitness and niche differences are both important in explaining responses of plant diversity to nutrient addition.

Plant species loss due to eutrophication is a common phenomenon in temperate perennial grasslands. It occurs in a non-random fashion and is usually explained by increased competitive size asymmetry between co-occurring winner (tall species with optima in productive habitats) and loser species (small-statured plants typical for unproductive habitats). It remains unclear why nutrient addition decreases diversity in communities consisting of losers only, whereas it has little effect on winner-only communities. Here, I used the framework of modern coexistence theory to explore fertilization-driven changes in fitness and niche differences between different combinations of field-identified winner (W) and loser (L) species. I experimentally estimated competition parameters for plant species pairs constructed from a pool of eight species, including pairs of species from the same (WW, LL) and different species categories (LW) grown for approximately two years in control and fertilized conditions. Concurrently, I also followed plant species diversity in mesocosm communities constructed from the same species pool (four-species communities including winners, losers, or both) exposed to control and nutrient addition. I found that nutrient addition can reduce but, unexpectedly, also promote species coexistence depending on the type of species pairs. Whereas nutrient addition eroded coexistence of losers with winners, but also with other losers, treatment had the opposite effect on the persistence of winner species. Fertilization induced large fitness differences between species in loser-winner and loser-loser combinations, but had little effect on the fitness differences of species within the winner-winner combination. In addition, the persistence of winner pairs was promoted by larger niche differences compared to loser species, irrespective of soil nutrients. The differences in how nutrient addition modified coexistence at the pairwise level was reflected by differences in evenness of multispecies communities assembled from the corresponding species categories. These results suggest that the effect of eutrophication on plant species richness cannot simply be explained by an increased competitive asymmetry. To fully understand the effect of fertilization on the diversity of temperate grasslands, interspecific and intraspecific interactions should be explored while considering differences in species' ecological optima. This article is protected by copyright. All rights reserved.

Stem Trait Spectra Underpin Multiple Functions of Temperate Tree Species.

A central paradigm in comparative ecology is that species sort out along a slow-fast resource economy spectrum of plant strategies, but this has been rarely tested for a comprehensive set of stem traits and compartments. We tested how stem traits vary across wood and bark of temperate tree species, whether a slow-fast strategy spectrum exists, and what traits make up this plant strategy spectrum. For 14 temperate tree species, 20 anatomical, chemical, and morphological traits belonging to six key stem functions were measured for three stem compartments (inner wood, outer wood, and bark). The trait variation was explained by major taxa (38%), stem compartments (24%), and species within major taxa (19%). A continuous plant strategy gradient was found across and within taxa, running from hydraulic safe gymnosperms to conductive angiosperms. Both groups showed a second strategy gradient related to chemical defense. Gymnosperms strongly converged in their trait strategies because of their uniform tracheids. Angiosperms strongly diverged because of their different vessel arrangement and tissue types. The bark had higher concentrations of nutrients and phenolics whereas the wood had stronger physical defense. The gymnosperms have a conservative strategy associated with strong hydraulic safety and physical defense, and a narrow, specialized range of trait values, which allow them to grow well in drier and unproductive habitats. The angiosperm species show a wider trait variation in all stem compartments, which makes them successful in marginal- and in mesic, productive habitats. The associations between multiple wood and bark traits collectively define a slow-fast stem strategy spectrum as is seen also for each stem compartment.

The hidden half of the fine root differentiation in herbs: nonacquisitive belowground organs determine fine‐root traits

Plants rely on roots for absorption of nutrients from the soil. Differences in traits of fine roots and of the root system in general thus underlie differences among individual species in their ability to live in habitats differing in nutrient status and interactions with other species. Here we examine to what extent structure of the root system is determined by whole‐plant parameters, namely the expected life span of the rooting units (either genetic individuals or ramets in clonally growing plants) and the type of belowground nonacquisitive organs such as rhizomes. By using phylogenetic comparative techniques we confirm the existence of two independent directions of variation in root traits, namely fast–slow continuum and cooperation continuum and show that the fast–slow continuum is associated with the increasing lifespan of the plant's rooting units (from annuals and stoloniferous species through rhizomatous species up to nonclonal perennial species). Lifespan of the rooting unit thus determines a range of root traits, namely root mass fraction (proportion of roots from the total biomass) and root tissue density. This shared continuum in root traits, life span of the rooting units and the type of belowground nonacquisitive organs is correlated with the environment where the species typically occur, with fast end (annual and stoloniferous species) occurring in productive and disturbed, and slow end (nonclonal perennials) in unproductive habitats. Further, clonal species have slightly shallower and thinner roots as their roots are relieved from the transport function which is served by horizontal stem‐derived organs (stolons and rhizomes). This confirms that plant lifespan and belowground nonacquisitive organs must be considered as determinants for (fine) root traits in herbs.

Putting non-structural compounds on the map of plant life history strategies: a commentary on Schoonmaker et al.

The seminal works of J. Philip Grime established that long-lived plants, like trees, have evolved a continuum of life strategies, spanning from competitors to stress tolerators, that optimize the capture and use of resources under habitats ranging from high to low productivity, respectively (Grime 1977, 2006). Competitors succeed in productive habitats by quickly capturing resources and colonizing space; resources are invested in new biomass to foster further capture. Conversely, the stress- tolerant strategy succeeds in unproductive habitats through a slow and costly-to-construct biomass, which does not require high rates of resource inputs but at the same time is highly resistant against potential losses of the invested resources (e.g., herbivory). These two strategies are comparable to the two end points of the leaf- or plant-economic spectrum, spanning from slow-growing–resource conservative to fast-growing–resource acquisitive (Reich et al. 1997, Westoby et al. 2002, Diaz et al. 2004...

Refrigeration or anti-theft? Food-caching behavior of wolverines (Gulo gulo) in Scandinavia

Food-caching animals can gain nutritional advantages by buffering seasonality in food availability, especially during times of scarcity. The wolverine (Gulo gulo) is a facultative predator that occupies environments of low productivity. As an adaptation to fluctuating food availability, wolverines cache perishable food in snow, boulders, and bogs for short- and long-term storage. We studied caching behavior of 38 GPS-collared wolverines in four study areas in Scandinavia. By investigating clusters of GPS locations, we identified a total of 303 food caches from 17 male and 21 female wolverines. Wolverines cached food all year around, from both scavenging and predation events, and spaced their caches widely within their home range. Wolverines cached food items on average 1.1 km from the food source and made between 1 and 6 caches per source. Wolverines cached closer to the source when scavenging carcasses killed by other large carnivores; this might be a strategy to optimize food gain when under pressure of interspecific competition. When caching, wolverines selected for steep and rugged terrain in unproductive habitat types or in forest, indicating a preference for less-exposed sites that can provide cold storage and/or protection against pilferage. The observed year-round investment in caching by wolverines underlines the importance of food predictability for survival and reproductive success in this species. Increasing temperatures as a consequence of climate change may provide new challenges for wolverines by negatively affecting the preservation of cached food and by increasing competition from pilferers that benefit from a warmer climate. It is however still not fully understood which consequences this may have for the demography and behavior of the wolverine.Significance statementFood caching is a behavioral strategy used by a wide range of animals to store food for future use. Choosing appropriate caching sites appears important for slowing down decomposition rates and minimizes competition. In this study, we demonstrate that the wolverine, an opportunistic predator and scavenger, utilizes available carrion to create caches all year around. By following wolverines with GPS collars, we registered that they carried food far away to cache it in secluded and cold places, which are often located on steep slopes or in forest. However, when scavenging other carnivores’ prey, they move food in shorter distances, possibly to be able to quickly return for more. The observed efficiency in wolverine caching behavior is likely vital for their survival and reproductive success in the harsh and highly seasonal environment in which they live.

Long‐term impacts of changed grazing regimes on the vegetation of heterogeneous upland grasslands

Abstract Marginal agricultural land, which in the UK refers to upland grazings in particular, is going to see changes in management driven by markets, subsidies, grants and environmental change with implications for biodiversity. Using a large‐scale, long‐term grazing experiment in the UK uplands we assessed the impact of intensification (tripling sheep numbers), abandonment (removal of sheep) and grazer diversification (partial replacement of sheep by cattle) on vegetation composition in a heterogenous area of grassland. Species benefiting from increased grazing included sweet vernal grass (Anthoxanthum odoratum), mat grass (Nardus stricta) and deer grass (Trichophorum cespitosum). Species that benefitted from the removal of grazing included bog asphodel (Narthecium ossifragum), bracken (Pteridium aquilinum) and blaeberry (Vaccinium myrtillus). Responses differed between vegetation communities; more productive acid grassland communities showed little change when grazing was removed, whilst less productive mire communities contained species, capable of increasing after grazing removal. Increased grazing and, to a lesser extent, the introduction of cattle increased species diversity. Synthesis and applications. Marginal agricultural grassland will likely see management change driven by markets, subsidies and environmental change. Vegetation change in these relatively infertile grasslands is slow and features shuffling dominance amongst species in the initial vegetation. Initial structural changes affect other trophic levels in this experiment; the slow change in composition will affect the system over longer timescales. Management decisions in the uplands encompass complex trade‐offs between production, biodiversity and a range of ecosystem services. Predicting the consequences of decisions is difficult given the slow dynamics of unproductive habitats.

Vegetation structure and decreased moth abundance limit the recolonisation of restored habitat by the European Nightjar

Woodland ecosystems of Europe have undergone major transitions in the last centuries. Changes in land use and the loss of natural forest dynamics have often led to structurally poor, uniform and dense stands. Not surprisingly, open forest species relying on a heterogeneous stand structure have suffered dramatic population declines. The European Nightjar Caprimulguseuropaeus, a nocturnal insectivorous bird, has undergone such a decline in its main Swiss stronghold in Valais. Despite the species’ potential to colonize new sites and habitat restoration measures implemented since 2001, recolonisation of restored sites has not taken place, suggesting problems with the current habitat restoration strategy. In order to refine management recommendations, we compared habitat structure and moth abundance, a key Nightjar food source, at sites that are still occupied and at sites that had been abandoned but have recently been restored. Vegetation structure was more heterogeneous and moth abundance greater at occupied than at abandoned sites. More specifically, occupied sites harboured a greater coverage of bare ground, while abandoned sites exhibited a higher amount of regeneration and intermediate shrub layer. The occurrence of natural perches was also higher in occupied sites. Abandoned sites are thus characterised by lower prey abundance and denser vegetation cover, the combination of which is likely to lead to lower prey availability for hunting Nightjars. Restoration action would benefit from maintaining snags and dead branches and by targeting unproductive habitats characterised by mineral soils, thereby slowing down regeneration and shrub regrowth. For future successful management of Nightjar habitats, it seems thereby essential trying to find the balance between actions that allow opening the lower and mid-strata of the forest while sustaining high moth populations.

Long-term functional structure and functional diversity changes in Scottish grasslands

Abstract Analysis of changes in functional traits and functional diversity offers a means of identifying the main environmental drivers of change, the impacts of that change on community assembly and the consequence of change on ecosystem function and service delivery. Changes in key traits and functional diversity in Scottish grasslands were analysed for a resurvey of 561 grasslands sampled an average of 40 years apart and these changes correlated with changes in environmental drivers. There were clear differences between the responses of different grassland habitats; more productive habitats showed evidence of increased agricultural utilisation, whereas more unproductive habitats showed evidence of reduced exploitation. This was echoed in an increase in Functional Richness in unproductive habitats and a decrease in productive ones; the latter indicating increased habitat filtering in the heavily utilised, productive habitats. There were also overall shifts to later-flowering species and less availability of resources for pollinators in less productive habitats. Models relating changes in traits to the environment had little power, but did indicate the importance of pollution and that recovery from the peak in livestock numbers between the surveys had not fully worked through. Similarly, changes in functional diversity were poorly explained by changes in environmental drivers, though increased rainfall had positive impacts on Functional Evenness and Richness. Functional Divergence (measured by Rao’s Q) was, however, strongly linked to changes in species traits over time. Scottish grasslands have diverged in how they have been utilised; more productive grasslands have been exploited more, resulting in shifts towards species with more exploitative growth strategies, a narrower range of growth and investment strategies, but a reduction in competitive dominance. The less productive grasslands appear to be utilised less, with shifts towards more conservative growth strategies and reduced habitat filtering, and the potential to deliver greater ecosystem multifunctionality. Resource declines for pollinators appeared to be universal across all grassland habitats.

Changes in the Spatial Configuration and Strength of Trophic Control Across a Productivity Gradient During a Massive Rodent Outbreak

Understanding the determinants of spatial and temporal differences in the relative strength of consumer–resource interactions is an important endeavour in ecology. Here, we explore the necessary conditions for temporal shifts in the relative strength of rodent–plant interactions in an area characterised by profound spatial differences in trophic control, with predator–prey interactions prevailing in productive habitats and rodent–plant interactions dominating unproductive habitats of the forest–tundra ecotone. We report data obtained during the exceptionally massive rodent outbreak of 2010–2012 in northernmost Fennoscandia, including an experimental manipulation of herbivore access to vegetation plots across a large-scale productivity gradient, multiple observational measures of plant–rodent interactions linked to rodent abundance data and a large-scale survey of breeding avian predators and mammalian predator activity. Unexpectedly, rodent grazing impacts documented during the rodent outbreak were uniformly strong across the landscape, regardless of habitat productivity. The runaway response in rodent populations was facilitated by a high population growth rate in the early phase of the outbreak due to the extended absence of predators in productive habitats, concomitant with an exceptionally long-lasting lemming outbreak in unproductive habitats. Our results showed that spatio-temporal variation in trophic control also occurs in ecosystems structured according to the exploitation ecosystems hypothesis and emphasises the importance of long-term studies to capture nonlinear and stochastic features that shape ecosystem functioning. In this context, the temporary release from top–down regulation in productive habitats caused strong grazing impacts that may be crucial for the resilience of tundra ecosystems under the threat of climate change-driven shrub encroachment.

Seedling recruitment in subalpine grassland forbs: Predicting field regeneration behaviour from lab germination responses

Environmental cueing that restricts seed germination to times and places where mortality risk is relatively low may have considerable selective advantage. The predictive power of lab germination responses for field regeneration behaviour is rarely tested. We screened 11 alpine grassland forbs for germination behaviour predictive of microsite and seasonal selectivity, and seed carry-over across years. The predictions were tested in a field experiment. Germination in the lab ranged from 0.05% to 67.9%, and was affected by light (5 species), temperature (6 species), fluctuating temperatures (4 species), moist chilling prior to germination (cold-stratification) (6 species), and dormancy-breaking by means of gibberellic acid (8 species). Seedling emergence in the field varied from 0.1% to 14.1%, and increased in low-competition microsites (bare-ground gaps and cut vegetation; 7 species), and showed seasonal timing (1 species in autumn and 1 species in spring), and seed carry-over across years (7 species). Lab germination responses successfully predicted microsite selectivity in the field and to some extent seed carry-over across years but not seasonal timing of germination. Gap-detecting species were generally small-seeded, low-growing, and found in unproductive habitats. Larger-seeded species germinated in all of the microsites but experienced increased mortality in high-competition microsites. Seed carry-over across years was lower for alpine specialists than for more widely-distributed species.

Inter‐annual fluctuations in rainfall shift the functional structure of Mediterranean grasslands across gradients of productivity and disturbance

AbstractQuestionsHow do inter‐annual fluctuations in water availability affect the functional trait patterns along spatial gradients of resource availability and disturbance?LocationMediterranean grasslands in central Spain, near Madrid.MethodsWe surveyed plant communities from 66 sites under different grazing regimes (from heavy grazing to grazing abandonment) in productive and unproductive habitats (corresponding to upper and lower topographic zones) in 2 yr with contrasting rainfall conditions. Community weighted mean (CWM) and Rao quadratic entropy for three key plant ecological strategy traits (specific leaf area, height and seed mass) were calculated for each community. We used null models to estimate functional richness (FR) and functional divergence (FD), the two components of functional diversity with the highest power to detect changes in community assembly processes across environmental gradients.ResultsThe patterns of CWM remained rather constant across years, with the only exception being seed mass, which experienced considerable temporal changes that suggested that heavy‐seeded species are favoured under stressful conditions. Patterns for FR were consistent across years. They revealed both trait convergence and divergence depending on the niche axis and context. Convergence was observed for vegetative traits in unproductive habitats and seed mass in productive ones, and divergence for seed mass in unproductive habitats and vegetative traits in productive ones. In contrast, the patterns of FD of the vegetative traits changed considerably between years, as shown by increased divergence during the wet year in unproductive habitats and decreased divergence in grazing‐abandoned productive habitats.ConclusionsTemporal changes in Mediterranean grassland composition depend on complex interactions between species traits, resource availability and disturbance. Increased rainfall appeared to have contrasting effects on assembly processes in stressful and productive habitats. In stressful habitats we found evidence that increased rainfall promoted niche complementarity, while in productive habitats, especially in the absence of disturbance, it increased trait convergence.

Clonal and bud bank traits: patterns across temperate plant communities

AbstractQuestionsWe examine patterns of clonal traits and below‐ground bud bank traits in plant communities over a large set of temperate vegetation types. We asked (i) how clonal traits are distributed in different community types and (ii) what are within‐community patterns of these traits as an indication of their role in species coexistence and community assembly.LocationCzech Republic.MethodsWe use a stratified set of more than 20,000 vegetation records from the Czech National Phytosociological Database as a source of species co‐occurrence and habitat type data, and combined it with data on clonal and bud bank traits from the CLO‐PLA database. We calculated both community trait means and dispersions for all records in the database and used a series of randomization tests to assess effects of environmental filtering and within‐community assembly.ResultsHabitat filtering was stronger in bud bank traits than in clonal traits. The key factors driving structure of clonal traits in Central Europe seem to be differences in productivity and in wetness. These gradients are responsible for a major change in clonal growth parameters, from clonal plants with short and persistent connections in dry and unproductive habitats to plants with long‐ and short‐lived connections in wet and productive sites. Size of the bud bank is rather uncorrelated with this gradient: species with small below‐ground bud bank size prevail in highly disturbed and in water habitats. None of the traits showed significant overdispersion, either at the level of the whole data set, or at the level of individual habitat types.ConclusionsCapacity for clonal growth occurs under many different environmental regimes and can give rise to very different growth forms. Therefore, using capacity for clonal growth as a proxy for clonal reproduction, capture of horizontal space or resprouting capacity may hinder understanding of its role. Absence of overdispersion after accounting for habitat filtering means that we found no evidence that clonal traits play a role in niche‐based coexistence processes.

Experimental demonstration of accelerated extinction in source-sink metapopulations.

Population extinction is a fundamental ecological process which may be aggravated by the exchange of organisms between productive (source) and unproductive (sink) habitat patches. The extent to which such source-sink exchange affects extinction rates is unknown. We conducted an experiment in which metapopulation effects could be distinguished from source-sink effects in laboratory populations of Daphnia magna. Time-to-extinction in this experiment was maximized at intermediate levels of habitat fragmentation, which is consistent with a minority of theoretical models. These results provided a baseline for comparison with experimental treatments designed to detect effects of concentrating resources in source patches. These treatments showed that source-sink configurations increased population variability (the coefficient of variation in abundance) and extinction hazard compared with homogeneous environments. These results suggest that where environments are spatially heterogeneous, accurate assessments of extinction risk will require understanding the exchange of organisms among population sources and sinks. Such heterogeneity may be the norm rather than the exception because of both the intrinsic heterogeneity naturally exhibited by ecosystems and increasing habitat fragmentation by human activity.

Can We Distinguish Plant Species that are Rare and Endangered from Other Plants Using Their Biological Traits?

Understanding the factors responsible for species rarity is crucial for effective species conservation. One possible approach to obtaining information about causes of species rarity is to compare rare and common species. We analyzed the biological and ecological traits of critically endangered (CR) plant species of the Czech Republic. We compared the vegetative, generative and ecological traits of CR species with: i) common closely related species (a form of phylogenetic correction), ii) common closely related species sharing the same habitat (i.e., excluding pairs not sharing the same habitat, because many differences in species traits can be caused by adaptation to a specific habitat type) and iii) all plants of the Czech Republic. Information about species traits was mainly obtained from literature and databases. Comparison with common closely related species showed that CR species are smaller, flower for shorter periods, and have higher proportions of self-compatibility and higher terminal velocities. CR species also differ in their mode of dispersion, and their ecology and distribution. Comparison with species from the same habitat gave similar results. Comparison with the whole flora produced slightly different results, with additional differences in pollination mode and seed mass. The results of all three types of comparison suggest that critically endangered species of the Czech Republic are small, competitively inferior species, with some differences in the generative part of their life cycle, and occur mainly in open, unproductive habitats.

Habitat quality influences population distribution, individual space use and functional responses in habitat selection by a large herbivore

Identifying factors shaping variation in resource selection is central for our understanding of the behaviour and distribution of animals. We examined summer habitat selection and space use by 108 Global Positioning System (GPS)-collared moose in Norway in relation to sex, reproductive status, habitat quality, and availability. Moose selected habitat types based on a combination of forage quality and availability of suitable habitat types. Selection of protective cover was strongest for reproducing females, likely reflecting the need to protect young. Males showed strong selection for habitat types with high quality forage, possibly due to higher energy requirements. Selection for preferred habitat types providing food and cover was a positive function of their availability within home ranges (i.e. not proportional use) indicating functional response in habitat selection. This relationship was not found for unproductive habitat types. Moreover, home ranges with high cover of unproductive habitat types were larger, and smaller home ranges contained higher proportions of the most preferred habitat type. The distribution of moose within the study area was partly related to the distribution of different habitat types. Our study shows how distribution and availability of habitat types providing cover and high-quality food shape ungulate habitat selection and space use.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-011-2072-3) contains supplementary material, which is available to authorised users.

The formation of species pools: historical habitat abundance affects current local diversity

Aim Explanations of biogeographic diversity patterns have emphasized the role of large-scale processes that determine species pools, whereas explanations of local patterns have not. We address the hypothesis that local diversity patterns are also primarily dependent on the size of the available species pools, which are expected to be large when the particular habitat type has been evolutionary more abundant, or in unproductive habitats due to shorter generation time and hence higher diversification rates.

Density dependence in an experimental boreal forest understory community

Density-dependent regulation in plants may occur at the level of the entire community and may differ in magnitude and direction at different life history stages such as germination, survival and growth, and under different abiotic conditions. We constructed semi-natural communities of boreal forest understory species planting 10 of the most abundant species. The experimental communities were established from seed or from cuttings and grown in sandboxes at six densities that extended far above and below average natural field density, while maintaining constant relative species proportions (a community density series (CDS)). We used two watering and fertilization levels in a factorial design. At the community level, both emergence and final per-plant shoot mass were negatively density dependent, while survival to the end of the season was facilitative. The effect of water was positive at seed emergence, whereas fertilizer negatively affected survival. Species-specific responses were also dependent on life stage. We demonstrated that density dependence is important in structuring this unproductive boreal understory habitat. The CDS approach allows us to quantify the effects of plant competition at the community and species levels, and to determine whether the importance of these biotic interactions depend on abiotic factors.

Reversed effects of grazing on plant diversity: the role of below‐ground competition and size symmetry

Grazing is known as one of the key factors for diversity and community composition in grassland ecosystems, but the response of plant communities towards grazing varies remarkably between sites with different environmental conditions. It is generally accepted that grazing increases plant diversity in productive environments, while it tends to reduce diversity in unproductive habitats (grazing reversal hypothesis). Despite empirical evidence for this pattern the mechanistic link between modes of plant–plant competition and grazing response at the community level still remains poorly understood. Root‐competition in particular has rarely been included in theoretical studies, although it has been hypothesized that variations in productivity and grazing regime can alter the relative importance of shoot‐ and root‐competition. We therefore developed an individual‐based model based on plant functional traits to investigate the response of a grassland community towards grazing. Models of different complexity, either incorporating only shoot competition or with distinct shoot‐ and root‐competition, were used to study the interactive effects of grazing, resource availability, and the mode of competition (size‐symmetric or asymmetric). The pattern predicted by the grazing reversal hypothesis (GRH) can only be explained by our model if shoot‐ and root‐competition are explicitly considered and if size asymmetry of above‐ and symmetry of below‐ground competition is assumed. For this scenario, the model additionally reproduced empirically observed plant trait responses: erect and large plant functional types (PFTs) dominated without grazing, while frequent grazing favoured small PFTs with a rosette growth form. We conclude that interactions between shoot‐ and root‐competition and size symmetry/asymmetry of plant–plant interactions are crucial in order to understand grazing response under different habitat productivities. Our results suggest that future empirical trait surveys in grassland communities should include root traits, which have been largely ignored in previous studies, in order to improve predictions of plants’ responses to grazing.

Thermoregulation in monotremes: riddles in a mosaic

The three extant genera of the Monotremata have evolved, probably from a pre-Cretaceous Gondwanan origin, independently of the Theria to display a variety of ancestral and derived features. A comparison of their thermoregulation reveals a diversity of physiology that might represent both plesiomorphic and apomorphic elements within this mosaic. In the tachyglossids, the echidnas Tachyglossus and Zaglossus, body temperature is often labile, rising as a result of activity and allowed to decline during inactivity. This daily heterothermy, which is not necessarily torpor, may combine with typical mammalian hibernation to provide substantial energy economy in a wide variety of often unproductive habitats. Only when incubating do free-ranging echidnas display classic mammalian thermoregulation, the facultative nature of which suggests echidna-like physiology as an example of a protoendothermic stage in the evolution of endothermy. Similarly, physiological response to heat in Tachyglossus, at least, may be plesiomorphic, relying on the cyclic loss of heat stored during activity. Tachyglossids neither exhibit a panting response nor spread saliva to facilitate evaporative cooling and Tachyglossus, though not Zaglossus, lacks functional sweat glands. By contrast, the only extant ornithorhynchid, the platypus Ornithorhynchus, does not utilise heterothermy of any kind and maintains its body temperature more tightly than several semiaquatic eutherians. Although not necessarily required, it responds to heat via sweating, but not panting or saliva spreading. The classic nature of ornithorhynchid thermoregulation stands in marked contrast to the more diverse thermoregulatory responses shown by the tachyglossids, making it difficult to determine which aspects of monotreme thermoregulation are plesiomorphic and which are apomorphic.

The Great Gobi B Strictly Protected Area in Mongolia ‐ refuge or sink for wolves Canis lupus in the Gobi

AbstractThe Mongolian hunting law does not mention the wolf Canis lupus, which is generally interpreted in the way that wolves can be hunted anytime and anywhere, including in protected areas. We investigated whether the Great Gobi B Strictly Protected Area (SPA), a strict nature reserve in southwestern Mongolia, acts as a refuge or a sink for wolves in the Gobi. Our expectations were that wolves in the Gobi 1) have large ranges similar to those in other equally unproductive habitats, 2) experience a high hunting pressure, and 3) have recently become an important export item for cross‐border trade to China. We combined GPS positions of two adult wolves, wolf harvest data and a market survey on wildlife products to address the above questions. Range use of the two collared wolves was huge, but varied widely between the two animals (6,670 km2 for an adult female and 26,619 km2 for an adult male) and over time. Reproductive status and residency status were only known during the initial 8‐months monitoring period of the female. During this ‘resident’ period her range size was 1,275 km2. Both wolves showed a clear preference of mountainous terrain over flat steppe, suggesting that only 21% of the SPA constitute preferred wolf habitat. Annual harvest in the park and its vicinity averaged 1 wolf/265 km2 in 2002/03, 1 wolf/120 km2 in 2003/04 and 1 wolf/310 km2 in 2004/05. However, hunting pressure was unequally distributed and particularly high in the northeastern corner of the park. During the active monitoring period of wolf F1, 35 wolves were killed within her ‘resident’ range, suggesting a high hunting pressure. Most wolves were shot from motorised vehicles, possibly explaining the preference of wolves for mountainous terrain which is inaccessible for vehicles. The market surveys revealed products from ∼2,000 wolves on the two border markets, a huge discrepancy to only 150 CITES permits officially issued annually. Although our data are insufficient to allow a truly quantitative assessment of the impact of human induced mortality on wolf conservation status in the Great Gobi B SPA, it points towards a potentially severe conservation problem requiring further attention.