Traditional fishing activities enhance the abundance of selected waterbird species in a wetland in India

Background:Waterbirds are globally declining as a result of habitat loss, alteration or degradation. Fishing activities may affect waterbird distribution, abundance and diversity, and traditional fishing activities often enhance waterbird abundance. We tested this hypothesis by studying the abundance and diversity of selected common waterbird species in the Kadalundi–Vallikkunnu Community Reserve, a globally significant wetland in southwestern India in relation to fishing activities.Methods:We monitored waterbird abundance four times a month from 2012 to 2015 using direct observation method during low tide. Traditional bamboo fish traps were deployed during the first and third weeks of each month. ANOVAs(one-way and multi-way) were used to examine how waterbird counts diversity varied in relation to years, seasons and period of fishing traps. Additionally we conducted a linear regression to examine the relationship between fish occurrence and waterbird counts and diversity.Results:Waterbird counts varied with years and seasons, with the maximum counts being recorded during the postmonsoon(winter). Individual species varied in their responses to trap deployment. Small waterbird species usually forage in shallow shorelines, increased during trap deployment whereas the larger waterbirds were not affected by trap deployment because they tend to hunt in deeper waters. The total fish captured was an important predictor of both waterbird abundance and diversity.Conclusion:In this study we documented a positive association between traditional fish trap deployment and waterbird counts and diversity. Providing high quality habitats for waterbirds as well as effective sustainable livelihoods through traditional fisheries is a critical management issue.

Breeding biology of a relictual Maghreb Magpie(Pica mauritanica)population in Tunisia

Background:The Maghreb Magpie(Pica mauritanica)is an endemic North African species.Available knowledge on this species is limited to historic descriptive data with no ecological information provided.Populations continue to dramatically decline in Tunisia,where only one relic population survives.Investigating the breeding biology of this species is essential for conservation purposes.The purpose of this study was to increase our understanding of the Tunisian relic population and provide detailed data on breeding biology over two breeding seasons(2017 and 2018).Methods:This study occurred on a private farm of 650 ha,located 10 km from Dhorbania village at Kairouan Governorate,in central Tunisia.Active nests were monitored weekly during egg laying period and twice a week during hatching period.The Ivlev's electivity index was used to assess whether the frequency of use of nesting trees and bushes matched their availability in the study area.We recorded nest measurements and positions,and compared them using Wilcoxon signed-rank test.Variations of breeding parameters as number of eggs laid,hatchlings,and fledglings over years were performed using Mann–Whitney U-test andχ^(2) tests.We used a Generalized Linear Mixed Model(GLMM)to investigate how egg volume varied with clutch size and laying date.Results:We investigated clutch size,egg size,hatching and fledging success,and evaluated how these parameters varied according to laying date and nest characteristics.Clutch size averaged 5.00±0.19 but was significantly greater nest.Causes of nest failure included the depredation of nestlings by shrikes,cobras and rats(e.g.Lanius meridionalis,Naja haje and Rattus rattus),death of parents by the Black-shouldered Kite(Elanus caeruleus)and nest parasitism by the Great Spotted Cuckoo(Clamator glandarius).Clutch size,brood size and fledgling success were unaffected by laying date,nest volume and nest elevation.Egg volume decreased with laying date but was unaffected by clutch.Conclusion:Our study provides the first and only detailed data on reproductive parameters of the Maghreb Magpie in its entire geographic range(North Africa).Information gleaned from this study provides valuable information for monitoring and long-term conservation plans of the endangered Tunisian Magpie population.Additionally,our data provide an avenue of large-scale comparative studies of the reproductive ecology of the magpie complex.