Terrestrial protected areas (PAs) are cornerstones of global biodiversity conservation. Their efficacy in terms of maintaining biodiversity is, however, much debated. Studies to date have been unable ...to provide a general answer as to PA conservation efficacy because of their typically restricted geographic and/or taxonomic focus, or qualitative approaches focusing on proxies for biodiversity, such as deforestation. Given the rarity of historical data to enable comparisons of biodiversity before/after PA establishment, many smaller scale studies over the past 30 years have directly compared biodiversity inside PAs to that of surrounding areas, which provides one measure of PA ecological performance. Here we use a meta-analysis of such studies (N = 86) to test if PAs contain higher biodiversity values than surrounding areas, and so assess their contribution to determining PA efficacy. We find that PAs generally have higher abundances of individual species, higher assemblage abundances, and higher species richness values compared with alternative land uses. Local scale studies in combination thus show that PAs retain more biodiversity than alternative land use areas. Nonetheless, much variation is present in the effect sizes, which underscores the context-specificity of PA efficacy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Body size is a key feature of organisms and varies continuously because of the effects of natural selection on the size‐dependency of resource acquisition and mortality rates. This review provides a ...critical and synthetic overview of body size variation in insects from a predominantly macroecological (large‐scale temporal and spatial) perspective. Because of the importance of understanding the proximate determinants of adult size, it commences with a brief summary of the physiological mechanisms underlying adult body size and its variation, based mostly on findings for the model species Drosophila melanogaster and Manduca sexta. Variation in nutrition and temperature have variable effects on critical weight, the interval to cessation of growth (or terminal growth period) and growth rates, so influencing final adult size. Ontogenetic and phylogenetic variation in size, compensatory growth, scaling at the intra‐ and interspecific levels, sexual size dimorphism, and body size optimisation are then reviewed in light of their influences on individual and species body size frequency distributions. Explicit attention is given to evolutionary trends, including gigantism, Cope's rule and the rates at which size change has taken place, and to temporal ecological trends such as variation in size with succession and size‐selectivity during the invasion process. Large‐scale spatial variation in size at the intraspecific, interspecific and assemblage levels is considered, with special attention being given to the mechanisms proposed to underlie clinal variation in adult body size. Finally, areas particularly in need of additional research are identified.
Lizard thermal trait variation at multiple scales: a review Clusella-Trullas, Susana; Chown, Steven L.
Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology,
01/2014, Letnik:
184, Številka:
1
Journal Article
Recenzirano
Thermal trait variation is of fundamental importance to forecasting the impacts of environmental change on lizard diversity. Here, we review the literature for patterns of variation in traits of ...upper and lower sub-lethal temperature limits, temperature preference and active body temperature in the field, in relation to space, time and phylogeny. Through time, we focus on the direction and magnitude of trait change within days, among seasons and as a consequence of acclimation. Across space, we examine altitudinal and latitudinal patterns, incorporating inter-specific analyses at regional and global scales. This synthesis highlights the consistency or lack thereof, of thermal trait responses, the relative magnitude of change among traits and several knowledge gaps identified in the relationships examined. We suggest that physiological information is becoming essential for forecasting environmental change sensitivity of lizards by providing estimates of plasticity and evolutionary scope.
Determining organismal responses to climate change is one of biology’s greatest challenges. Recent forecasts for future climates emphasize altered temperature variation and precipitation, but most ...studies of animals have largely focused on forecasting the outcome of changes in mean temperature. Theory suggests that extreme thermal variation and precipitation will influence species performance and hence affect their response to changes in climate. Using an information-theoretic approach, we show that in squamate ectotherms (mostly lizards and snakes), two fitness-influencing components of performance, the critical thermal maximum and the thermal optimum, are more closely related to temperature variation and to precipitation, respectively, than they are to mean thermal conditions. By contrast, critical thermal minimum is related to mean annual temperature. Our results suggest that temperature variation and precipitation regimes have had a strong influence on the evolution of ectotherm performance, so that forecasts for animal responses to climate change will have to incorporate these factors and not only changes in average temperature.
Antarctica is widely regarded as one of the planet's last true wildernesses, insulated from threat by its remoteness and declaration as a natural reserve dedicated to peace and science. However, ...rapidly growing human activity is accelerating threats to biodiversity. We determined how well the existing protected-area system represents terrestrial biodiversity and assessed the risk to protected areas from biological invasions, the region's most significant conservation threat. We found that Antarctica is one of the planet's least protected regions, with only 1.5% of its ice-free area formally designated as specially protected areas. Five of the distinct ice-free ecoregions have no specially designated areas for the protection of biodiversity. Every one of the 55 designated areas that protect Antarctica's biodiversity lies closer to sites of high human activity than expected by chance, and seven lie in high-risk areas for biological invasions. By any measure, including Aichi Target 11 under the Convention on Biological Diversity, Antarctic biodiversity is poorly protected by reserves, and those reserves are threatened.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Heat freezes niche evolution Araújo, Miguel B.; Ferri-Yáñez, Francisco; Bozinovic, Francisco ...
Ecology letters,
September 2013, Letnik:
16, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Climate change is altering phenology and distributions of many species and further changes are projected. Can species physiologically adapt to climate warming? We analyse thermal tolerances of a ...large number of terrestrial ectotherm (n = 697), endotherm (n = 227) and plant (n = 1816) species worldwide, and show that tolerance to heat is largely conserved across lineages, while tolerance to cold varies between and within species. This pattern, previously documented for ectotherms, is apparent for this group and for endotherms and plants, challenging the longstanding view that physiological tolerances of species change continuously across climatic gradients. An alternative view is proposed in which the thermal component of climatic niches would overlap across species more than expected. We argue that hard physiological boundaries exist that constrain evolution of tolerances of terrestrial organisms to high temperatures. In contrast, evolution of tolerances to cold should be more frequent. One consequence of conservatism of upper thermal tolerances is that estimated niches for cold‐adapted species will tend to underestimate their upper thermal limits, thereby potentially inflating assessments of risk from climate change. In contrast, species whose climatic preferences are close to their upper thermal limits will unlikely evolve physiological tolerances to increased heat, thereby being predictably more affected by warming.
Marine food webs destabilized Chown, Steven L.
Science (American Association for the Advancement of Science),
08/2020, Letnik:
369, Številka:
6505
Journal Article
Recenzirano
A combination of warming and acidification threaten marine biomass and productivity
Forecasting the ecological consequences of climate change requires both observations and experiments. Among the ...most informative experiments are manipulations of ecosystems, either through large outdoor interventions or through the construction of mesocosms (
1
)—replicas of the natural world that enable conditions to be carefully controlled. Mesocosms typically mimic the complexity of natural ecosystems, enabling researchers to disentangle how these systems work now and what path they might follow as future conditions change. They can also be replicated, enabling signal to be distinguished from the variability that is an inherent feature of natural systems. On page 829 of this issue, Nagelkerken
et al.
(
2
) report on their use of mesocosms to better understand the future of marine systems and the ecological services they deliver. They find that marine benthic ecosystems have limited capacity to respond to a future combination of warming and acidification, with considerable degradation a potential outcome.
Rate dynamics of ectotherm responses to thermal stress Kovacevic, Aleksandra; Latombe, Guillaume; Chown, Steven L
Proceedings of the Royal Society. B, Biological sciences,
05/2019, Letnik:
286, Številka:
1902
Journal Article
Recenzirano
Odprti dostop
Critical thermal limits (CTLs) show much variation associated with the experimental rate of temperature change used in their estimation. Understanding the full range of variation in rate effects on ...CTLs and their underlying basis is thus essential if methodological noise is not to overwhelm or bias the ecological signal. We consider the effects of rate variation from multiple intraspecific assessments and provide a comprehensive empirical analysis of the rate effects on both the critical thermal maximum (CT
) and critical thermal minimum (CT
) for 47 species of ectotherms, exploring which of the available theoretical models best explains this variation. We find substantial interspecific variation in rate effects, which takes four different forms (increase, decline, no change, mixed), with phylogenetic signal in effects on CT
, but not CT
. Exponential and zero exponential failure rate models best explain the rate effects on CT
. The majority of the empirical rate variation in CT
could not be explained by the failure rate models. Our work demonstrates that rate effects cannot be ignored in comparative analyses, and suggests that incorporation of the failure rate models into such analyses is a useful further avenue for exploration of the fundamental basis and implications of such variation.
1. Terrestrial ectotherms are likely to face increased periods of heat stress as mean temperatures and temperature variability increase over the next few decades. Here, we consider the extent to ...which changes in upper thermal limits, through plasticity or evolution, might be constrained, and we survey insect and reptile data to identify groups likely to be particularly susceptible to thermal stress. 2. Plastic changes increase thermal limits in many terrestrial ectotherms, but tend to have less effect on upper limits than lower limits. 3. Although comparisons across insect species have normally not taken into account the potential for plastic responses, mid-latitude species seem most prone to experience heat stress now and into the future, consistent with data from lizards and other groups. 4. Evolutionary adaptive potential has only been measured for some species; there is likely to be genetic variation for heat responses in populations, but selection and heritability experiments suggest that upper thermal limits may not increase much. 5. Although related species can differ by several degrees in their upper thermal limits, there is strong phylogenetic signal for upper limits. If these reflect evolutionary constraints, substantial molecular changes may be required to increase upper thermal limits. 6. Findings point to many terrestrial ectotherms having a limited potential to change their thermal limits particularly within the context of an average predicted temperature increase of 2—4 °C for mid-latitude populations over the next few decades.
Antarctic biodiversity is much more extensive, ecologically diverse and biogeographically structured than previously thought. Understanding of how this diversity is distributed in marine and ...terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of diversity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic biodiversity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewhere.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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