No room to roam: King Cobras reduce movement in agriculture

Benjamin Michael Marshall,Surachit Waengsothorn,Cameron Wesley Hodges,Taksin Artchawakom,Pongthep Suwanwaree,Matt Crane,Colin Thomas Strine,Inês Silva,Matt Goode,Max Dolton Jones

doi:10.1186/s40462-020-00219-5

Benjamin Michael Marshall, Surachit Waengsothorn + Show 8 more

Open Access

https://doi.org/10.1186/s40462-020-00219-5

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Abstract

BackgroundStudying animal movement provides insights into how animals react to land-use changes. As agriculture expands, we can use animal movement to examine how animals change their behaviour in response. Recent reviews show a tendency for mammalian species to reduce movements in response to increased human landscape modification, but reptile movements have not been as extensively studied.MethodsWe examined movements of a large reptilian predator, the King Cobra (Ophiophagus hannah), in Northeast Thailand. We used a consistent regime of radio telemetry tracking to document movements across protected forest and adjacent agricultural areas. Using dynamic Brownian Bridge Movement Model derived motion variance, Integrated Step-Selection Functions, and metrics of site reuse, we examined how King Cobra movements changed in agricultural areas.ResultsMotion variance values indicated that King Cobra movements increased in forested areas and tended to decrease in agricultural areas. Our Integrated Step-Selection Functions revealed that when moving in agricultural areas King Cobras restricted their movements to remain within vegetated semi-natural areas, often located along the banks of irrigation canals. Site reuse metrics of residency time and number of revisits appeared unaffected by distance to landscape features (forests, semi-natural areas, settlements, water bodies, and roads). Neither motion variance nor reuse metrics were consistently affected by the presence of threatening landscape features (e.g. roads, human settlements), suggesting that King Cobras will remain in close proximity to threats, provided habitat patches are available.ConclusionsAlthough King Cobras displayed individual heterogeneity in their response to agricultural landscapes, the overall trend suggested reduced movements when faced with fragmented habitat patches embedded in an otherwise inhospitable land-use matrix. Movement reductions are consistent with findings for mammals and forest specialist species.

Highlights

Examining animal movement can provide important information on conspecific interactions [1], predator-prey dynamics [2, 3], reproductive behaviours [4], and responses to anthropogenic threats [5, 6]
We examined how site-reuse patterns changed in relation to anthropogenic landscape features
King Cobras occupied an average of 524 ± 104.5 unique locations, covering large areas in both protected and unprotected areas (Table 1; Fig. 1), with adult males tending to move more than our single tracked female and two tracked juveniles

Summary

Introduction

Examining animal movement can provide important information on conspecific interactions [1], predator-prey dynamics [2, 3], reproductive behaviours [4], and responses to anthropogenic threats [5, 6]. Anthropogenic land-use can alter the landscape’s ecology, changing resources [11], modifying behaviour [12], and introducing novel threats [13]. Such changes can result in increased mortality of species, or subtler sublethal costs [14,15,16]. Recent reviews show a tendency for mammalian species to reduce movements in response to increased human landscape modification, but reptile movements have not been as extensively studied

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