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1.
Oecologia ; 198(2): 531-542, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34999944

RESUMO

Ecosystem engineers affect other organisms by creating, maintaining or modifying habitats, potentially supporting species of conservation concern. However, it is important to consider these interactions alongside non-engineering trophic pathways. We investigated the relative importance of trophic and non-trophic effects of an ecosystem engineer, red deer, on a locally rare moth, the transparent burnet (Zygaena purpuralis). This species requires specific microhabitat conditions, including the foodplant, thyme, and bare soil for egg-laying. The relative importance of grazing (i.e., trophic effect of modifying microhabitat) and trampling (i.e., non-trophic effect of exposing bare soil) by red deer on transparent burnet abundance is unknown. We tested for these effects using a novel method of placing pheromone-baited funnel traps in the field. Imago abundance throughout the flight season was related to plant composition, diversity and structure at various scales around each trap. Indirect effects of red deer activity were accounted for by testing red deer pellet and trail presence against imago abundance. Imago abundance was positively associated with thyme and plant diversity, whilst negatively associated with velvet grass and heather species cover. The presence of red deer pellets and trails were positively associated with imago abundance. The use of these sites by red deer aids the transparent burnet population via appropriate levels of grazing and the provision of a key habitat condition, bare soil, in the form of deer trails. This study shows that understanding how both trophic and non-trophic interactions affect the abundance of a species provides valuable insights regarding conservation objectives.


Assuntos
Cervos , Mariposas , Animais , Ecossistema , Plantas , Solo
2.
J Anim Ecol ; 86(4): 960-971, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28390110

RESUMO

Understanding why heterogeneity exists in animal-habitat spatial relationships is critical for identifying the drivers of animal distributions. Functional responses in habitat selection - whereby animals adjust their habitat selection depending on habitat availability - are useful for describing animal-habitat spatial heterogeneity. However, they could be yielded by different movement tactics, involving contrasting interspecific interactions. Identifying functional responses in animal movement, rather than in emergent spatial patterns like habitat selection, could disentangle the effects of different movement behaviours on spatial heterogeneity in animal-habitat relationships. This would clarify how functional responses in habitat selection emerge and provide a general tool for understanding the mechanistic drivers of animal distributions. We tested this approach using data from GPS-collared woodland caribou (Rangifer tarandus), a prey species under top-down control. We tested how caribou selected and moved with respect to a key resource (lichen-conifer stands) as a function of the availability of surrounding refuge land-cover (closed-conifer stands), using step selection functions. Caribou selected resource patches more strongly in areas richer in refuge land-cover - a functional response in habitat selection. However, adjustments in multiple movement behaviours could have generated this pattern: stronger directed movement towards resource patches and/or longer residency within resource patches, in areas richer in refuges. Different contributions of these behaviours would produce contrasting forager spatial dynamics. We identified functional responses in both movement behaviours: caribou were more likely to move towards resource patches in areas richer in refuge land-cover, and to remain in these patches during movement steps. This tactic enables caribou to forage for longer in safer areas where they can rapidly seek refuge in dense cover when predators are detected. Our study shows that functional responses in movement can expose the context-dependent movement decisions that generate heterogeneity in animal-habitat spatial relationships. We used these functional responses to characterise anti-predator movement tactics employed by a large herbivore, but they could be applied in many different scenarios. The movement rules from functional responses in movement are well-suited to integration in spatial explicit individual-based models for forecasting animal distributions in landscapes undergoing environmental change.


Assuntos
Distribuição Animal , Meio Ambiente , Rena , Animais , Ecossistema , Movimento
3.
Glob Chang Biol ; 20(12): 3872-82, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24957266

RESUMO

The altitudinal shifts of many montane populations are lagging behind climate change. Understanding habitual, daily behavioural rhythms, and their climatic and environmental influences, could shed light on the constraints on long-term upslope range-shifts. In addition, behavioural rhythms can be affected by interspecific interactions, which can ameliorate or exacerbate climate-driven effects on ecology. Here, we investigate the relative influences of ambient temperature and an interaction with domestic sheep (Ovis aries) on the altitude use and activity budgets of a mountain ungulate, the Alpine chamois (Rupicapra rupicapra). Chamois moved upslope when it was hotter but this effect was modest compared to that of the presence of sheep, to which they reacted by moving 89-103 m upslope, into an entirely novel altitudinal range. Across the European Alps, a range-shift of this magnitude corresponds to a 46% decrease in the availability of suitable foraging habitat. This highlights the importance of understanding how factors such as competition and disturbance shape a given species' realised niche when predicting potential future responses to change. Furthermore, it exposes the potential for manipulations of species interactions to ameliorate the impacts of climate change, in this case by the careful management of livestock. Such manipulations could be particularly appropriate for species where competition or disturbance already strongly restricts their available niche. Our results also reveal the potential role of behavioural flexibility in responses to climate change. Chamois reduced their activity when it was warmer, which could explain their modest altitudinal migrations. Considering this behavioural flexibility, our model predicts a small 15-30 m upslope shift by 2100 in response to climate change, less than 4% of the altitudinal shift that would be predicted using a traditional species distribution model-type approach (SDM), which assumes that species' behaviour remains unchanged as climate changes. Behavioural modifications could strongly affect how species respond to a changing climate.


Assuntos
Altitude , Migração Animal/fisiologia , Mudança Climática , Ecossistema , Comportamento de Retorno ao Território Vital , Modelos Biológicos , Ruminantes/fisiologia , Animais , Itália , Especificidade da Espécie
4.
Am Nat ; 180(6): 823-30, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23149406

RESUMO

Age-dependent reproductive timing has been observed in females of a number of species; older females often breed earlier in the season and experience higher reproductive success as a result. However, to date, evidence for within-season variation in reproductive effort (RE) for males has been relatively weak. Males are expected to time RE in light of intraseasonal variations in the availability of receptive females and competition with other males. Young males, which are typically smaller and less experienced, might benefit from breeding later in the season, when male-male competition is less intense. Using a long-term data set of Alpine chamois Rupicapra rupicapra, we sought to evaluate the hypothesis that younger males allocate highest RE late in the breeding season, at a time when older male RE has decreased substantially. Our results support this hypothesis, which suggests that intraseasonal variation in RE may be an adaptive life-history trait for males as well as females.


Assuntos
Peso Corporal , Rupicapra/fisiologia , Comportamento Sexual Animal , Fatores Etários , Animais , Itália , Masculino , Estações do Ano
5.
Conserv Sci Pract ; 3(2): e316, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33655201

RESUMO

Conservation conflicts are damaging for humans and wildlife, with differences in people's objectives fuelling challenges of managing complex, dynamic systems. We investigate the relative importance of economic, psychological (affect, trust and risk perception) and ecological factors in determining farmers' management preferences, using Greenland barnacle geese (Branta leucopsis) on Islay, Scotland, as a case study. Barnacle geese reduce agricultural productivity on Islay, negatively impacting household economies. Since 1992, farmers have received partial compensation but a new culling scheme has escalated conflict between conservation and agricultural interests. Using a questionnaire, we collected data from 75% of the farmers receiving goose payments. We found that affect was a strong driver of both risk perception and management preferences. However, we revealed complexity in these relationships, with trust and economic factors also influencing decision-making. Psychological and economic factors surrounding wildlife management must be understood if we are to achieve conservation objectives in human dominated landscapes.

6.
Ecol Evol ; 9(19): 11089-11101, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31641457

RESUMO

Conflict between stakeholders with opposing interests can hamper biodiversity conservation. When conflicts become entrenched, evidence from applied ecology can reveal new ways forward for their management. In particular, where disagreement exists over the efficacy or ethics of management actions, research clarifying the uncertain impacts of management on wildlife can move debates forwards to conciliation.Here, we explore a case-study of entrenched conflict where uncertainty exists over the impacts of multiple management actions: namely, moorlands managed for the shooting of red grouse (willow ptarmigan) Lagopus lagopus in the United Kingdom (UK). Debate over how UK moorlands should be managed is increasingly polarized. We evaluate, for the first time at a regional scale, the relative impacts of two major moorland management practices-predator control and heather burning-on nontarget bird species of conservation concern.Birds were surveyed on 18 estates across Northern England and Southeast Scotland. Sites ranged from intensively managed grouse moors to moorland sites with no management for grouse shooting. We hypothesised that both targeted predator control and burning regimes would enhance ground-nesting wader numbers and, as a consequence of this, and of increased grouse numbers, nontarget avian predators should also be more abundant on heavily managed sites.There were positive associations between predator control and the abundance of the three most widespread species of ground-nesting wader: strong effects for European golden plover Pluvialis apricaria and Eurasian curlew Numenius arquata and, less strongly, for common snipe Gallinago gallinago. These effects saturated at low levels of predator control. Evidence for effects of burning was much weaker. We found no evidence of enhanced numbers of nontarget predators on heavily managed sites.

7.
Conserv Lett ; 12(1): e12450, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31007719

RESUMO

The management of conflicts between wildlife conservation and agricultural practices often involves the implementation of strategies aimed at reducing the cost of wildlife impacts on crops. Vital to the success of these strategies is the perception that changes in management efforts are synchronized relative to changes in impact levels, yet this expectation is never evaluated. We assess the level of synchrony between time series of population counts and management effort in the context of conflicts between agriculture and five populations of large grazing birds in northern Europe. We reveal inconsistent patterns of synchrony and asynchrony between changes in population counts and impact management effort relating to population harvesting, monetary payments, or scaring practices. This variation is likely due to differing management aims, the existence of lags between management decisions and population monitoring, and the inconsistent use of predictive models across case studies. Overall, our findings highlight the need for more adaptive and timely responses of management to changes in target species numbers so as not to unexpectedly increase social conflicts and jeopardize the status of wildlife populations.

8.
Conserv Lett ; 11(6): e12460, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30774714

RESUMO

Conservation conflict is widespread, damaging, and has proved difficult to manage using conventional conservation approaches. Conflicts are often "wicked problems," lacking clear solutions due to divergent values of stakeholders, and being embedded within wickedly complex environments. Drawing on the concept of wicked environmental problems could lead to management strategies better suited to tackling conflict. However, it is unclear whether managers are embracing ideas from the wicked problems concept. There is currently a lack of guidance for applying strategies to tackle particular wicked problems, such as conservation conflict. We explored the suitability of wicked problems-inspired management, using eight contemporary conflict case studies. Conservation conflict was managed predominantly using conventional approaches suited to tackling single objectives in simple environments, rather than balancing competing objectives in complex environments. To deal with different characteristics of wickedness, we recommend that managers develop strategies combining distributed decision-making, diverse opinions, pattern-based predictions, trade-off-based objectives, and reporting of failures. Recent advances in conservation conflict research have focused on improving interactions among stakeholders. We believe that such stakeholder-focused approaches would dovetail with the whole-system focus of a wicked problems framework, allowing conservationists to move toward a holistic strategy for managing conservation conflict.

10.
PLoS One ; 6(11): e28002, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22125651

RESUMO

BACKGROUND: A fundamental life history question is how individuals should allocate resources to reproduction optimally over time (reproductive allocation). The reproductive restraint hypothesis predicts that reproductive effort (RE; the allocation of resources to current reproduction) should peak at prime-age, whilst the terminal investment hypothesis predicts that individuals should continue to invest more resources in reproduction throughout life, owing to an ever-decreasing residual reproductive value. There is evidence supporting both hypotheses in the scientific literature. METHODOLOGY/PRINCIPAL FINDINGS: We used an uncommonly large, 38 year dataset on Alpine chamois (Rupicapra rupicapra) shot at various times during the rutting period to test these two hypotheses. We assumed that body mass loss in rutting males was strongly related to RE and, using a process-based approach, modelled how male relative mass loss rates varied with age. For different regions of our study area, we provide evidence consistent with different hypotheses for reproductive allocation. In sites where RE declined in older age, this appears to be strongly linked to declining body condition in old males. In this species, terminal investment may only occur in areas with lower rates of body mass senescence. CONCLUSIONS/SIGNIFICANCE: Our results show that patterns of reproductive allocation may be more plastic than previously thought. It appears that there is a continuum from downturns in RE at old age to terminal investment that can be manifest, even across adjacent populations. Our work identifies uncertainty in the relationship between reproductive restraint and a lack of competitive ability in older life (driven by body mass senescence); both could explain a decline in RE in old age and may be hard to disentangle in empirical data. We discuss a number of environmental and anthropogenic factors which could influence reproductive life histories, underlining that life history patterns should not be generalised across different populations.


Assuntos
Peso Corporal/fisiologia , Modelos Biológicos , Reprodução/fisiologia , Rupicapra/fisiologia , Envelhecimento/fisiologia , Algoritmos , Animais , Feminino , Geografia , Itália , Estágios do Ciclo de Vida , Masculino , Rupicapra/crescimento & desenvolvimento , Fatores de Tempo
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