Survival strategies on a semi-arid island: submersion and desiccation tolerances of fiddler crabs from the Galapagos Archipelago

AbstractDuring tidal cycles, semi-terrestrial fiddler crabs are subject to alternating periods of submersion and desiccation. Here, we compare physiological and biochemical adjustments to forced submersion and desiccation in two fiddler crabs from the Galapagos archipelago: the indigenous Leptuca helleri, and Minuca galapagensis. We examine ecological distributions and habitat characteristics using transect analysis; survival after 6 h forced submersion at different salinities (0, 21 and 42 ‰S), and after 6 or 12 h desiccation challenge, including alterations in hemolymph osmolality; and, oxidative stress responses in the gills and hepatopancreas, accompanying glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) activities, and lipid peroxidase (LPO). We provide an integrated biomarker response (IBR) index for each species based on oxidative stress in each tissue and condition. Our transect study revealed that L. helleri occupies an intertidal niche while M. galapagensis is supralittoral, L. helleri being less resistant to submersion and desiccation. After 6 h submersion, L. helleri survived only at 21 ‰S while M. galapagensis survived at all salinities. Hemolymph osmolality decreased at 0 ‰S in M. galapagensis. After 6 h desiccation, osmolality decreased markedly in L. helleri but increased in M. galapagensis. Enzyme assays were not performed in L. helleri owing to high mortality on submersion/desiccation challenge. After submersion in M. galapagensis, hepatopancreas GPx activities decreased in 0 and 21 ‰S while GR activity was strongly inhibited at all salinities. Gill LPO decreased in 42 ‰S. On desiccation in L. helleri, GPx activity was inhibited in the hepatopancreas but increased in the gills. GST activity increased while LPO decreased in both tissues. After desiccation in M. galapagensis, hepatopancreas GPx activity increased. Both hepatopancreas and gill GST and GR activities and LPO were strongly inhibited. The IBR indexes for L. helleri were highest in fresh caught crabs, driven by gill and hepatopancreas LPO. For M. galapagensis, submersion at 21 ‰S contributed most to IBR, LPO in both tissues responding markedly. Leptuca helleri appears to be a habitat specialist adapted to a narrow set of niche dimensions while M. galapagensis survives over a much wider range, exhibiting little oxidative stress. The species’ physiological flexibilities and limitations provide insights into how fiddler crabs might respond to global environmental change on semi-arid islands.

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The Role of Social Networks as Survival Strategies in Agro-Pastoral Communities in Arid And Semi-Arid Lands in Tanzania

Asian Development Policy Review ◽

10.18488/journal.107.2017.52.90.99 ◽

2017 ◽

Vol 5 (2) ◽

pp. 90-99

Author(s):

Rematus Rusomyo ◽

He Junlin ◽

Catherine Mangare

Keyword(s):

Social Networks ◽

Arid Lands ◽

Survival Strategies ◽

Pastoral Communities ◽

Semi Arid

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Dealing with drought: social implications of different smallholder survival strategies in semi-arid rangelands of Northern Patagonia, Argentina

The Rangeland Journal ◽

10.1071/rj09071 ◽

2010 ◽

Vol 32 (2) ◽

pp. 247 ◽

Cited By ~ 22

Author(s):

Marcos H. Easdale ◽

Heber Rosso

Keyword(s):

Arid Regions ◽

Social Impact ◽

Animal Husbandry ◽

Survival Strategies ◽

Farm Income ◽

Farm Productivity ◽

Farm Production ◽

Gross Income ◽

On Farm ◽

Semi Arid

Drought is a constant part of rangeland dynamics in arid and semi-arid regions, and has enormous impacts on extensive livestock production by reducing outputs as well as by generating short-term farm decapitalisation (e.g. when livestock die). Since rural people rely on animal husbandry for their livelihood, productive losses become a social problem. Approaches to deal with drought have generally been focused on the livestock–range management linkage, with many suggestions originating from different disciplines. However, fewer efforts had been made to understand the adaptive capacity of households to cope with drought, through changing from on-farm to off-farm approaches. We assessed the implications for household gross income of different smallholder survival strategies, in the context of a severe regional drought. Three strategies were selected: (i) social networks involving partnerships, (ii) income diversification, and (iii) farm production diversification. While drought impacted homogeneously on the production indicators among the different strategies, differences were apparent in household economic performance. Better prices obtained from associated sales and off-farm income strategies registered better household gross income levels. For these cases the effect of drought on farm productivity could be decoupled from household income. Results provide new insights in understanding the social impact of drought on rangelands, challenging current ideas about how governments can support poorest and most vulnerable farmers in rural arid and semi-arid regions.

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Climate Variability, Climate Change and Social Vulnerability in the Semi-arid Tropics

10.1017/cbo9780511608308 ◽

1996 ◽

Cited By ~ 42

Keyword(s):

Climate Change ◽

Climate Variability ◽

Social Vulnerability ◽

Semi Arid

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Ferrihydrite dissolution at the root zone of crops under semi-arid condition controls the plant uptake of uranium and arsenic

10.1021/scimeetings.0c03694 ◽

2020 ◽

Author(s):

Arindam Malakar ◽

Michael Kaiser ◽

Daniel D. Snow ◽

Harkamal Walia ◽

Chittaranjan Ray

Keyword(s):

Plant Uptake ◽

Root Zone ◽

Arid Condition ◽

Semi Arid

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Analytic Survival Strategies

PsycEXTRA Dataset ◽

10.1037/e404652005-016 ◽

1996 ◽

Author(s):

Maureen Murphy ◽

Karen Rosica

Keyword(s):

Survival Strategies

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Life strategies in a semi-arid grassland community — mechanisms of dispersal and reproduction within Lapiedro martinezii-Stipetum tenacissimae (Southeastern Spain)

Feddes Repertorium ◽

10.1002/fedr.4921100310 ◽

1999 ◽

Vol 110 (3-4) ◽

pp. 265-285 ◽

Cited By ~ 1

Author(s):

I. Hensen

Keyword(s):

Life Strategies ◽

Grassland Community ◽

Southeastern Spain ◽

Semi Arid

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Sustainable Illegality: Gagauz Women in Istanbul

MIGRATION LETTERS ◽

10.33182/ml.v8i1.150 ◽

2014 ◽

Vol 8 (1) ◽

pp. 17-25 ◽

Cited By ~ 1

Author(s):

Bayram Unal

Keyword(s):

Police Officers ◽

Ethnic Origin ◽

Social Processes ◽

Survival Strategies ◽

Preferential Treatment ◽

National Group ◽

Turkish Migrants ◽

Illegal Migrants ◽

Sociological Inquiry ◽

The Social

This study deals with survival strategies of illegal migrants in Turkey. It aims to provide an explanation for the efforts to keep illegality sustainable for one specific ethnic/national group—that is, the Gagauz of Moldova, who are of Turkish ethnic origin. In order to explicate the advantages of Turkish ethnic origin, I will focus on their preferential treatment at state-law level and in terms of the implementation of the law by police officers. In a remarkable way, the juridical framework has introduced legal ways of dealing with the illegality of ethnically Turkish migrants. From the viewpoint of migration, the presence of strategic tools of illegality forces us to ask not so much law-related questions, but to turn to a sociological inquiry of how and why they overstay their visas. Therefore, this study concludes that it is the social processes behind their illegality, rather than its form, that is more important for our understanding of the migrants’ survival strategies in destination countries.

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THE CLASSIFICATION OF LAND ACCORDING TO THE DEGREE OF RABBIT INFESTATION IN CENTRAL OTAGO

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1987.48.1792 ◽

1987 ◽

pp. 65-70

Author(s):

I.G.C. Kerr ◽

J.M. Williams ◽

W.D. Ross ◽

J.M. Pollard

Keyword(s):

Carrying Capacity ◽

Mediterranean Climate ◽

Natural Habitat ◽

Public Funding ◽

Soil Survey ◽

European Rabbit ◽

Cultural Modification ◽

Classification Information ◽

Semi Arid

The European rabbit (Oryctolagus cuniculus) introduced into New Zealand in the 183Os, has consistently flourished in Central Otago, the upper Waitaki, and inland Marlborough, all areas of mediterranean climate. It has proved difficult to manage in these habitats. The 'rabbit problem' is largely confined to 105,000 ha of low producing land mostly in semi arid areas of Central Otago. No field scale modifications of the natural habitat have been successful in limiting rabbit numbers. The costs of control exceed the revenue from the land and continued public funding for control operations appears necessary. A system for classifying land according to the degree of rabbit proneness is described. Soil survey and land classification information for Central Otago is related to the distribution and density of rabbits. This intormation can be used as a basis for defining rabbit carrying capacity and consequent land use constraints and management needs. It is concluded that the natural rabbit carrying capacity of land can be defined by reference to soil survey information and cultural modification to the natural vegetation. Classification of land according to rabbit proneness is proposed as a means of identifying the need for, and allocation of, public funding tor rabbit management. Keywords: Rabbit habitat, rabbit proneness, use of rabbit prone land.

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