Biology subjects

Salguero-Gomez, R.

Publications and source records attributed to Salguero-Gomez, R..

7 recordsLinked to original sources

bioRxiv2020

Towards a comparative framework of demographic resilience

In times of global biodiversity crisis, developing tools to define, quantify, compare and predict ecological resilience is essential for understanding species responses to global change. Disparate interpretations of ecological resilience have, however, hampered the development of a common currency to quantify and compare resilience across natural systems. Most frameworks of study have focused on upper levels of biological organisation, especially ecosystems or communities, which adds layers of complication to measuring resilience with empirical data. To overcome such limitations, we suggest quantifying resilience using demographic data. Surprisingly, a quantifiable definition of resilience does not exist at the demographic level. Here, we present a framework of demographic resilience with a set of metrics that are comparable across species, and facilitate cost-effective management decisions.

ecology↗

bioRxiv2019

Global analysis reveals complex demographic responses of mammals to climate change

Approximately 25 % of mammals are threatened globally with extinction, a risk that is amplified under climate change1. Persistence under climate change is determined by the combined effects of climatic factors on multiple demographic rates (survival, development, reproduction), and hence, on population dynamics2. Thus, to quantify which species and places on Earth are most vulnerable to climate-driven extinction, a global understanding of how demographic rates respond to climate is needed3. We synthesise information on such responses in terrestrial mammals, where extensive demographic data are available4. Given the importance of assessing the full spectrum of responses, we focus on studies that quantitatively link climate to multiple demographic rates. We identify 106 such studies, corresponding to 86 mammal species. We reveal a strong mismatch between the locations of demographic studies and the regions and taxa currently recognised as most vulnerable to climate change5,6. Moreover, we show that the effects of climate change on mammals will operate via complex demographic mechanisms: a vast majority of mammal populations display projected increases in some demographic rates but declines in others. Assessments of population viability under climate change therefore need to account for multiple demographic responses. We advocate to prioritise coordinated actions to assess mammal demography holistically for effective conservation worldwide.

ecology↗

bioRxiv2019

Tree demographic performance of European tree species at their hot and cold edges.

O_LISpecies range limits are thought to result from a decline in demographic performance at range edges. However, recent studies reporting contradictory patterns in species demographic performance at their edges cast doubt on our ability to predict climate change demographic impacts. To understand these inconsistent demographic responses at the edges, we need to shift the focus from geographic to climatic edges and analyse how species responses vary with climatic constraints at the edge and species ecological strategy. C_LIO_LIHere we parameterised integral projection models with climate and competition effects for 27 tree species using forest inventory data from over 90,000 plots across Europe. Our models estimate size-dependent climatic responses and evaluate their effects on two life trajectory metrics: lifespan and passage time - the time to grow to a large size. Then we predicted growth, survival, lifespan, and passage time at the hot and dry or cold and wet edges and compared them to their values at the species climatic centre to derive indices of demographic response at the edge. Using these indices, we investigated whether differences in species demographic response between hot and cold edges could be explained by their position along the climate gradient and functional traits related to their climate stress tolerance. C_LIO_LIWe found that at cold and wet edges of European tree species, growth and passage time were constrained, whereas at their hot and dry edges, survival and lifespan were constrained. Demographic constraints at the edge were stronger for species occurring in extreme conditions, i.e. in hot edges of hot-distributed species and cold edges of cold-distributed species. Species leaf nitrogen content was strongly linked to their demographic responses at the edge. In contrast, we found only weak links with wood density, leaf size, and xylem vulnerability to embolism. C_LIO_LISynthesis. Our study presents a more complicated picture than previously thought with demographic responses that differ between hot and cold edges. Predictions of climate change impacts should be refined to include edge and species characteristics. C_LI

ecology↗

bioRxiv2019

Not all seabird species can overcome marine threats when predator removal at their colonies is prioritised

Seabirds are globally threatened. In the face of multiple threats, it is critical to understand how conservation strategies that mitigate one threat intersect with others to impact population viability. Marine threats, including pollution, climate change, and fisheries could derail gains to seabird populations resulting from arduous predator eradication efforts. However, this potentially negative effect is yet to be evaluated. We test whether mortality from marine threats can subvert the on-going recovery of 17 seabird species from 37 colonies on islands worldwide where predators were removed. We use demographic modelling to estimate potential adult mortality from fisheries, plastic ingestion, and climate change. For 82% of the species we examine, marine threats do not impede recovery following predator eradication. However, for six colonies of three species, Calonectris diomedea, C. borealis, and Ardenna carneipes, mortality from multiple marine threats may interrupt their recovery. Combining our demographic approach with comparative phylogenetic methods, we explore whether foraging niche, range, and morphometric traits inform the vulnerability to marine threats using an expanded dataset of 81 seabird species. Our analyses reveal surface filtering and pursuit diving species, and species with smaller at-sea distributions to be most vulnerable to declines due to multiple threats. However, these traits do not necessarily predict species vulnerability to marine threats in the absence of predators at nesting colonies, suggesting that shared traits may not be useful to infer vulnerability to multiple marine threats. Post-eradication monitoring to determine whether species require additional conservation management following predator eradication are essential in the face of intensifying pressures in the marine environment.

ecology↗

bioRxiv2019

Testing Finch’s hypothesis: the role of organismal modularity on the escape from actuarial senescence

O_LIUntil recently, senescence was assumed to be a universal phenomenon. Evolutionary theories of senescence predict that no organism may escape the physiological decline that results in an increase in mortality risk and/or decline in fertility with age. However, evidence both in animals and plants has emerged in the last decade defying such predictions. Researchers are currently seeking mechanistic explanations for the observed variation in ageing trajectories.\nC_LIO_LIWe argue that the historical view on the inevitability of senescence is due, in part, to the development of its classical theories, which targeted primarily unitary organisms. In unitary species, the integration of resources and functions is high, and adult size is determined. In contrast, the architecture of modular organisms is indeterminate and built upon repeated modules. The isolation of mortality risk in species like hydra (Hydra spp.) or creosote brush (Larrea tridentata) may explain their null or even negative senescence.\nC_LIO_LICaleb Finch hypothesised three decades ago that species with the ability to compartmentalise risk may escape senescence. Here, we first review the evidence on organisms that slow down or even avoid senescence in the context of their architecture, along a continuum of unitarity-modularity. Then, we use open-access databases to comparatively analyse various moments of senescence and link longevity to the degree of anatomic modularity. Our analysis compares 138 plants and 151 animals. Our comparative analysis reveals that plant species that are more modular do indeed tend to escape from senescence more often than those that are unitary. The role of modularity in animal senescence is less clear.\nC_LIO_LIIn light of novel support for Finchs hypothesis across a large diversity of plant species, and with less conclusive findings in animals, we identify new research directions. We highlight opportunities related to age-dependent mortality factors. Other areas for further research include the role of modularity in relation to endocrine actions, and the costs of modular anatomies.\nC_LI O_QD\"The actinozooid is a living thing which knows no time of youthful vigour, no waxing to a period of adult life, no waxing to senility - it knows no age - it practically knows no natural death.\" - Wood-Jones (1912)\n\nC_QD

ecology↗

bioRxiv2019

Using a residency index to estimate the economic value of saltmarsh provisioning services for commercially important fish species

Every year, 100 hectares of saltmarsh in the United Kingdom are lost due to sea level rise. The remaining areas are threatened by land conversion, agricultural activities, and climate change. There are important economic consequences to saltmarsh loss, as saltmarsh provides valuable ecosystem services including flood protection, carbon sequestration, and nursery habitat for commercially fished species. Quantifying the economic value of these ecosystem services can help target policies for saltmarsh restoration, or managed realignment, of new saltmarsh areas. In this study, we quantify the economic value of saltmarsh as a habitat for commercially fished species by developing a residency index. The residency index weights the relative importance of saltmarsh along a species lifecycle by explicitly incorporating the target species life histories and the estimated proportion of time it spends in saltmarsh at juvenile and adult life stages. Using this index, we estimate the value of saltmarsh to UK commercial fisheries landings. We find that UK saltmarsh contributes annually between 16.7% and 18.2% of total UK commercial landings for European seabass (Dicentrarchus labrax), European plaice (Pleuronectes platessa), and Common sole (Solea solea). Our findings highlight the importance of saltmarsh protection and restoration. Furthermore, our approach provides a general framework that integrates population ecology methods and economic analyses to assess the value of saltmarsh and other coastal habitats for fisheries worldwide.

ecology↗

bioRxiv2019

Aquatic and terrestrial organisms display contrasting life history strategies as a result of environmental adaptations

AimsAquatic and terrestrial realms display stark differences in key environmental factors and phylogenetic composition. Despite such differences, their consequences for the evolution of species life history strategies remain poorly understood. Here, we examine whether and how life history strategies vary between terrestrial and aquatic species.\n\nLocationGlobal.\n\nTime periodVariable, the earliest year being in 1906 and the most recent in 2015.\n\nMajor taxa studiesMacroscopic animals and plants species.\n\nMethodsWe use demographic information for 638 terrestrial and 117 aquatic animal and plant species, to derive key life history traits capturing their population turnover, and investments in survival, development, and reproduction. We use phylogenetically corrected least squares regression to explore the differences in the trade-offs between life history traits in both realms. We then quantify the life history strategies of aquatic and terrestrial species using a phylogenetically corrected principal component analysis.\n\nResultsWe find that the same trade-offs structure terrestrial and aquatic life histories, resulting in two dominant axes of variation describing species pace- of-life and reproductive spread through time. Life history strategies differ between aquatic and terrestrial environments, with phylogenetic relationships playing a minor role. We show that adaptations of plants and animals to terrestrial environments have resulted in different life history strategies, particularly with their reproductive mode and longevity. Terrestrial plants display a great diversity of life history strategies, including the species with the longest lifespans. Aquatic animals, on the contrary, exhibit higher reproductive frequency than terrestrial animals, likely due to reproductive adaptations (i.e. internal fecundation) of the later to land.\n\nMain conclusionsOur findings show that aquatic and terrestrial species are ruled by the same life history principles, but have evolved different strategies due to distinct selection pressures. Such contrasting life history strategies have important consequences for the conservation and management of aquatic and terrestrial species.

ecology↗