scholarly journals Consequences of barriers and changing seasonality on population dynamics and harvest of migratory ungulates

2020 ◽  
Vol 13 (4) ◽  
pp. 595-605
Author(s):  
Bram Van Moorter ◽  
Steinar Engen ◽  
John M. Fryxell ◽  
Manuela Panzacchi ◽  
Erlend B. Nilsen ◽  
...  

AbstractMany animal populations providing ecosystem services, including harvest, live in seasonal environments and migrate between seasonally distinct ranges. Unfortunately, two major sources of human-induced global change threaten these populations: climate change and anthropogenic barriers. Anthropogenic infrastructure developments present a global threat to animal migrations through increased migration mortality or behavioral avoidance. Climate change alters the seasonal and spatial dynamics of resources and therefore the effects of migration on population performance. We formulated a population model with ideal-free migration to investigate changes in population size and harvest yield due to barriers and seasonal dynamics. The model predicted an increasing proportion of migrants when the difference between areas in seasonality or carrying capacity increased. Both migration cost and behavioral avoidance of barriers substantially reduced population size and harvest yields. Not surprisingly, the negative effects of barriers were largest when the population benefited most from migration. Despite the overall decline in harvest yield from a migratory population due to barriers, barriers could result in locally increased yield from the resident population following reduced competition from migrants. Our approach and results enhance the understanding of how global warming and infrastructure development worldwide may change population dynamics and harvest offtake affecting livelihoods and rural economies.

Author(s):  
Roberto Ambrosini ◽  
Andrea Romano ◽  
Nicola Saino

Studies of the timing (phenology) of bird migration provided some of the first evidence for the effects of climate change on organisms. Since the rate of climate change is uneven across the globe, with northern latitudes experiencing faster warming trends than tropical areas, animals moving across latitudes are subject to diverging trends of climate change at different stages of their annual life cycle, and, consequently, they can become mistimed with the local ecological conditions, with potentially negative effects on population size. This chapter reviews the modifications induced by climate change in different migration traits, like the timing of migration events, the distribution of organisms, and the direction and the speed of movements. It also considers the effects of ecological carry-over effects and migratory connectivity on the response of birds to climate change.


Author(s):  
Bernt-Erik Sæther ◽  
Steinar Engen ◽  
Marlène Gamelon ◽  
Vidar Grøtan

Climate variation strongly influences fluctuations in size of avian populations. In this chapter, we show that it is difficult to predict how the abundance of birds will respond to climate change. A major reason for this is that most available time series of fluctuations in population size are in a statistical sense short, thus often resulting in large uncertainties in parameter estimates. We therefore argue that reliable population predictions must be based on models that capture how climate change will affect vital rates as well as including other processes (e.g. density-dependences) known to affect the population dynamics of the species in question. Our survey of examples of such forecast studies show that reliable predictions necessarily contain a high level of uncertainty. A major reason for this is that avian population dynamics are strongly influenced by environmental stochasticity, which is for most species, irrespective of their life history, the most important driver of fluctuations in population size. Credible population predictions must therefore assess the effects of such uncertainties as well as biases in population estimates.


2020 ◽  
Vol 1 (4) ◽  
pp. 141-156
Author(s):  
Attila J. Trájer

The Pliocene era could be the last time when sandfly (Diptera: Psychodidae) species were widespread in Europe. Within the Pliocene, the mid-Pliocene period is an important model period in the investigation of the future effects of anthropogenic climate change. In this study, the mid-Pliocene potential distribution of six Mediterranean sandfly species was modelled based on the M2 mid-Pliocene cold and mid-Pliocene warm paleoclimatic reconstructions. It was found that the cold period’s potential occurrence of sandfly species could be notably more extended than the distribution of the taxa in the warm period. The difference is less expressed in the case of the West Mediterranean species, but it is particularly visible in the circum-Mediterranean and East Mediterranean taxa. It can be concluded that not the changes in the mean annual temperature, but the increase of the precipitation patterns and the wetter climate of the mid-Pliocene warm period resulted in the observed differences. The results imply that the use of mid-Pliocene warming as a model of the present climatic changes can be handled with caution in the performing of biogeographic proxies for vector sandflies related to the anthropogenic climate change.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5568 ◽  
Author(s):  
Amaël Borzée ◽  
Desiree Andersen ◽  
Yikweon Jang

Amphibian populations fluctuate naturally in size and range and large datasets are required to establish trends in species dynamics. To determine population trends for the endangered Suweon Treefrog (Dryophytes suweonensis), we conducted aural surveys in 2015, 2016, and 2017 at each of 122 sites where the species was known to occur in the Republic of Korea. Despite being based on individual counts, the focus of this study was to establish population trends rather than population size estimates, and we found both environmental and landscape variables to be significant factors. Encroachment was also a key factor that influenced both the decreasing number of calling individuals and the negative population dynamics, represented here by the difference in the number of calling individuals between years. Generally, most sites displayed minimal differences in the number of calling males between years, although there was a large fluctuation in the number of individuals at some sites. Finally, when adjusted for the overall population size difference between years, we found the population size to be decreasing between 2015 and 2017, with a significant decrease in the number of calling individuals at specific sites. High rate of encroachment was the principal explanatory factor behind these marked negative peaks in population dynamics.


2016 ◽  
Vol 6 (2) ◽  
pp. 1 ◽  
Author(s):  
Ross Gittell ◽  
Josh Stillwagon

<p>This paper explores the influence of US state-level policies meant to address climate change on clean technology industry development. The largest influence of climate change policies is identified as being on energy research employment. Only some policies seem to contribute positively to clean tech employment while other policies appear to discourage employment growth. The magnitudes of the short term effects, even when statistically significant, are modest. Negative impacts on employment are identified for several mandate-oriented, so called command and control, policies including vehicle greenhouse gas standards, energy efficiency resource standards, and renewable portfolio standards with the former two having increasing negative effects over time. The findings suggest that climate change policy advocates should be careful to not assume that there will be positive clean tech employment benefits from state-level energy and environmental policies. Instead, the benefits from these policies may derive primarily from other considerations beyond the scope of this paper, including health and environmental benefits and reduction of dependence on foreign energy sources.</p>


2021 ◽  
Vol 13 (6) ◽  
pp. 1180
Author(s):  
Da Guo ◽  
Xiaoning Song ◽  
Ronghai Hu ◽  
Xinming Zhu ◽  
Yazhen Jiang ◽  
...  

The Hindu Kush Himalayan (HKH) region is one of the most ecologically vulnerable regions in the world. Several studies have been conducted on the dynamic changes of grassland in the HKH region, but few have considered grassland net ecosystem productivity (NEP). In this study, we quantitatively analyzed the temporal and spatial changes of NEP magnitude and the influence of climate factors on the HKH region from 2001 to 2018. The NEP magnitude was obtained by calculating the difference between the net primary production (NPP) estimated by the Carnegie–Ames Stanford Approach (CASA) model and the heterotrophic respiration (Rh) estimated by the geostatistical model. The results showed that the grassland ecosystem in the HKH region exhibited weak net carbon uptake with NEP values of 42.03 gC∙m−2∙yr−1, and the total net carbon sequestration was 0.077 Pg C. The distribution of NEP gradually increased from west to east, and in the Qinghai–Tibet Plateau, it gradually increased from northwest to southeast. The grassland carbon sources and sinks differed at different altitudes. The grassland was a carbon sink at 3000–5000 m, while grasslands below 3000 m and above 5000 m were carbon sources. Grassland NEP exhibited the strongest correlation with precipitation, and it had a lagging effect on precipitation. The correlation between NEP and the precipitation of the previous year was stronger than that of the current year. NEP was negatively correlated with temperature but not with solar radiation. The study of the temporal and spatial dynamics of NEP in the HKH region can provide a theoretical basis to help herders balance grazing and forage.


2021 ◽  
Vol 13 (12) ◽  
pp. 6517
Author(s):  
Innocent Chirisa ◽  
Trynos Gumbo ◽  
Veronica N. Gundu-Jakarasi ◽  
Washington Zhakata ◽  
Thomas Karakadzai ◽  
...  

Reducing vulnerability to climate change and enhancing the long-term coping capacities of rural or urban settlements to negative climate change impacts have become urgent issues in developing countries. Developing countries do not have the means to cope with climate hazards and their economies are highly dependent on climate-sensitive sectors such as agriculture, water, and coastal zones. Like most countries in Southern Africa, Zimbabwe suffers from climate-induced disasters. Therefore, this study maps critical aspects required for setting up a strong financial foundation for sustainable climate adaptation in Zimbabwe. It discusses the frameworks required for sustainable climate adaptation finance and suggests the direction for success in leveraging global climate financing towards building a low-carbon and climate-resilient Zimbabwe. The study involved a document review and analysis and stakeholder consultation methodological approach. The findings revealed that Zimbabwe has been significantly dependent on global finance mechanisms to mitigate the effects of climate change as its domestic finance mechanisms have not been fully explored. Results revealed the importance of partnership models between the state, individuals, civil society organisations, and agencies. Local financing institutions such as the Infrastructure Development Bank of Zimbabwe (IDBZ) have been set up. This operates a Climate Finance Facility (GFF), providing a domestic financial resource base. A climate change bill is also under formulation through government efforts. However, numerous barriers limit the adoption of adaptation practices, services, and technologies at the scale required. The absence of finance increases the vulnerability of local settlements (rural or urban) to extreme weather events leading to loss of life and property and compromised adaptive capacity. Therefore, the study recommends an adaptation financing framework aligned to different sectoral policies that can leverage diverse opportunities such as blended climate financing. The framework must foster synergies for improved impact and implementation of climate change adaptation initiatives for the country.


2021 ◽  
Vol 260 ◽  
pp. 109187
Author(s):  
Quezia Ramalho ◽  
Luara Tourinho ◽  
Mauricio Almeida-Gomes ◽  
Mariana M. Vale ◽  
Jayme A. Prevedello

Author(s):  
Jerelle A. Jesse ◽  
M. Victoria Agnew ◽  
Kohma Arai ◽  
C. Taylor Armstrong ◽  
Shannon M. Hood ◽  
...  

AbstractDiseases are important drivers of population and ecosystem dynamics. This review synthesizes the effects of infectious diseases on the population dynamics of nine species of marine organisms in the Chesapeake Bay. Diseases generally caused increases in mortality and decreases in growth and reproduction. Effects of diseases on eastern oyster (Crassostrea virginica) appear to be low in the 2000s compared to effects in the 1980s–1990s. However, the effects of disease were not well monitored for most of the diseases in marine organisms of the Chesapeake Bay, and few studies considered effects on growth and reproduction. Climate change and other anthropogenic effects are expected to alter host-pathogen dynamics, with diseases of some species expected to worsen under predicted future conditions (e.g., increased temperature). Additional study of disease prevalence, drivers of disease, and effects on population dynamics could improve fisheries management and forecasting of climate change effects on marine organisms in the Chesapeake Bay.


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